APPENDIX F ECOLOGY AND BIOLOGICAL ASSESSMENT
This appendix contains two major sections. Section F.1 is a discussion of the ecological characteristics at the LLNL Livermore site, LLNL Site 300, and SNL, Livermore (referred to collectively as the study sites); and presents information and data on the flora and fauna in the upland areas (see Appendix G for a detailed analysis of wetlands at the study sites). This section focuses on the biological features of LLNL Site 300 because this 7000-acre site is largely undeveloped and represents the most biologically diverse area under study. In contrast, the LLNL Livermore site and SNL, Livermore are developed areas that provide only marginal wildlife habitat because of the high degree of human activity and the few areas of undisturbed vegetation.
Section F.2, a biological assessment, complies with the U.S. Department of Energy (DOE) guidelines requiring that a biological assessment be prepared in conjunction with an environmental impact statement. Prepared pursuant to Section 7(c) of the U.S. Endangered Species Act and to the State of California Endangered Species Act, this biological assessment includes a description of existing biological conditions; the status of threatened and endangered species and other species of concern at the study sites; the impacts, if any, of operations on these species; a determination if effects would occur to species of concern; and mitigation measures where appropriate.
The relationship of Appendix F to other appendices and to Sections 4 and 5 of the EIS/EIR is illustrated in Figure F-1. While analyses prepared for the biological assessment provide the basis for the discussion of impacts of the proposed action as described in the EIS/EIR section 5.1.7.3, the biological assessment analyzes a broader scope of actions than does the EIS/EIR. This broader description, including analysis of the biological impacts of existing operations, is appropriate to DOE requirements as well as state and federal endangered species acts.
Flora references in section F.1 are generally made using scientific names since common names of plant species are not always available. For fauna references in sections F.1 and F.2, the reverse is generally the case, with common names preceding the scientific names, which are in parentheses.
F.1 ECOLOGY
F.1.1 Flora and Vegetation
The flora and vegetation at LLNL Site 300 have been described in Taylor and Davilla (1986a, 1986b). Because of the extensive scope of this previous study no additional studies of flora and vegetation other than surveys for rare plants were conducted in 1991. A limited amount of information regarding flora and vegetation at the LLNL Livermore site and SNL, Livermore has been collected.
F.1.1.1 Methods
A plant species list for LLNL Site 300 was generated during the 1986 rare plant surveys (conducted on foot beginning on March 30, 1986, and continuing at biweekly intervals through mid-May 1986) (Taylor and Davilla, 1986b). All plant species observed during these surveys were recorded on the plant species list.
Sampling to typify vegetation composition was conducted in 1986 using a rapid, descriptive technique generally termed as "the relevé method" (Mueller-Dombois and Ellenberg, 1974). Sites that qualified for relevé sampling were judged to possess homogeneous physiography and edaphic characteristics. Relevé size was determined by the rate of observation of the new species within a homogeneous patch of vegetation with the relevé boundary being the point where observation of new species ceased (Daubenmire, 1968).
Cover of vascular plant species within the relevé was estimated according to the following scale of precision:
| Observed Cover Value | Estimated to the Nearest |
| <1% | 0.1% |
| 1–10% | 1.0% |
| >10% | 5.0% |
Mean percent cover was determined as the average for all relevés in which a given species occurred, not the mean for all relevés. Constancy and importance values for plant species found within each plant community type were also calculated. Constancy is the percentage of all relevés in which a given species is encountered. Importance values are the sum of constancy and mean cover. As such, the importance value is a parameter that represents the frequency at which a species is observed added to the percent of groundcover of this particular species.
The survey also recorded the elevation, slope, exposure, and edaphic characteristics at each relevé site. Soil texture was estimated using visual and tactile methods (U.S. Department of Agriculture, 1951).
Data Analysis
The purpose of the analysis of vegetation data was to provide an ecological description of the LLNL Site 300 plant communities based on quantitative methods. The ecological characterization presented below is adapted from the 1986 report by Taylor and Davilla (1986a). Data collected in this study was analyzed using a variety of univariate and multivariate techniques. The object of these analyses was to quantify patterns of vegetative variation in relation to environmental factors. A detailed discussion of the methods used appears in Taylor and Davilla (1986a).
Vegetation Mapping
A standard map of habitat types was prepared for LLNL Site 300 by dividing a color photograph of the site into polygons (Avery, 1968), each corresponding to a structurally homogeneous expanse of vegetation. The available image was made at an appropriate stage of plant growth for mapping purposes (late April) when contrast between xeric (dry) and mesic (moist to wet) habitats was best developed. Mapped boundaries of each vegetation polygon were transferred to a base map using a stereo zoom transfer scope. Relevés within each polygon were compared in order to derive more detailed map units.
F.1.1.2 Results
Flora
From the 1986 survey, a total of 342 plant taxa were identified at LLNL Site 300 (Taylor and Davilla, 1986b) (Table F-1); 308 of these were recorded from the 218 relevés sampled (Figure F-2), representing a sampling intensity of 8.1 relevés/km2 (21.0 relevés/mi2). Relevé density varied from 5.1 to 121.7 relevés/km2 (13.2 to 315.2 relevés/mi2); more relevés were sampled in the southwestern portion of LLNL Site 300 because of its diverse topography and vegetation.
Of the 308 plant taxa identified in the 218 relevés, 88 species (29 percent) occurred on at least 4 relevés (Table F-2 ). The non-native grass species, Avena barbata, was the most frequently encountered plant occurring in more than 87 percent of all relevés and having a mean cover of approximately 37 percent, more than three times higher than the species with the next highest cover. Other frequently encountered species were Bromus mollis, B. diandrus, Erodium cicutarium, B. rubens, and Vulpia myuros, all non-native annuals introduced from Europe (Robbins, 1940). Collectively, these six taxa are dominant in annual grasslands over much of lowland California (Heady, 1977).
The proportion and relative importance of native versus introduced species in the vegetation on LLNL Site 300 are similar to patterns documented in other cismontane annual grassland communities, where a handful of introduced species dominate and native species are less common (Heady, 1958; Talbot et al., 1939; Pitt, 1975).
Poa scabrella was the most important native grass identified, occurring on nearly 39 percent of all relevés with an average cover of about 8 percent. Other important native species included the annual herbs Trifolium tridentatum, Orthocarpus purpurascens, Lotus subpinnatus, and Amsinckia intermedia.
Community Type Classification
Plant community classification analysis and ordination techniques resulted in the delineation of 14 plant community types that were combined to form five major types (Figure F-3, Table F-3). Of the 218 relevés sampled, 6 could not be placed in the classification scheme. Of these relevés, two were from the vernal pool and the remaining four were in other unique habitats (a clay scald, a Quercus lobata stand, an unusual landslide deposit dominated by Grindelia camporum, and a Melica californica sward) for which no replicate samples could be obtained.
Characteristics of the plant community types including number of stands sampled, elevation, aspect, soil, and number of species per stand are presented in Table F-4. The cover of the various life forms within each plant community type is on Table F-5.
Coastal Sage Scrub Community
The scrub communities identified from LLNL Site 300 can be characterized as mixtures of the soft-chaparral shrubs Artemisia californica, Eriogonum fasciculatum, Salvia mellifera, and Gutierrezia bracteata. These four taxa form the nucleus of coastal sage scrub vegetation, which is most commonly associated with the outer south coast ranges of California (Westman, 1981; Mooney, 1977). The mean number of species for coastal sage scrub community types is generally higher than other types on LLNL Site 300 (Table F-4). These community types occur in the southwestern part of LLNL Site 300 (Figure F-3) and cover approximately 108 acres.
Community type 1 (Artemisia californica-Salvia mellifera/Herniaria cinerea) is typified by high cover (approximately 44 percent) of the shrubs Gutierrezia bracteata, Artemisia californica, Eriogonum fasciculatum, and Salvia mellifera (Table F-5). Understory vegetation is dominated by introduced grasses (37 percent cover), predominantly Avena barbata (Table F-5). The large proportion of bare ground present in most stands of this type can be attributed to the combined effects of allelopathy and rabbit grazing (Halligan, 1975; Muller et al., 1964; Bartholomew, 1970). Community type 1 occurs on rocky outcrops of resistant sandstone or on alluvial conglomerates on moderate to steep slopes facing south to west (Table F-4).
The composition and structure of community type 1 most closely resembles coastal sage scrub communities from coastal southern California as described by Kirkpatrick and Hutchinson (1980), Wells (1962), and Westman (1981). Internal percentage similarity between stands of this type is 66 percent (Table F-4).
Community type 2 (Artemisia californica/Bromus mollis) is a restricted vegetation unit on LLNL Site 300, occurring only along the slopes and on the bottoms of gullies in the southern half of the site, whose structure is intermediate between those of typical coastal sage scrub and grassland. Shrub cover averages about 23 percent, and grass cover averages about 64 percent (Table F-5). Artemisia californica is the dominant shrub species, while predominant grass species (all introduced) are Bromus mollis, B. diandrus, Avena barbata, Vulpia myuros, and B. rubens. Internal percentage similarity averages 63 percent within this community type (Table F-4).
Community type 3 (Gutierrezia bracteata/Avena barbata), also a transitional type between coastal sage scrub and grassland, typically consists of a sparse shrub cover (14 percent) dominated by Gutierrezia bracteata. Grass cover, almost entirely of introduced grasses, is approximately 58 percent (Table F-5), with Avena barbata being the most common species. This vegetation is typical of ridges and flat terraces on moderate slopes underlain by hard conglomerates exhibiting poorly developed soils (Table F-4).
Oak Woodland Community
A single oak-woodland community type, community type 4 (Quercus douglasii/Avena barbata), is found on LLNL Site 300. Stands are restricted to north-facing slopes in southern canyons on the site (Figure F-3) and cover approximately 150 acres. This type includes a sparse cover of Quercus douglasii (averaging 13 percent) and a complete grass–dominated understory (Table F-5). Important grasses include Avena barbata, Bromus mollis, and B. diandrus. Only one native grass, Elymus triticoides, is important in this vegetation. As is typical of other California oak woodland communities (Griffin, 1977), the spatial distribution of understory grasses is patchy correlating with the effect of shade and litterfall associated with a canopy (and formerly, with the leisure habits of cattle) (Holland, 1973).
Internal similarity is low compared to that of most other community types in this study, whereas species richness is relatively high (Table F-4). Ecologically, oak woodland dominated by Q. douglasii is most often located in slightly more mesic sites than those supporting annual grasslands (Baker et al., 1981).
Introduced Grassland Communities
The four introduced grassland community types from LLNL Site 300, covering approximately 5647 acres, are variously proportioned mixtures of introduced annual grasses (Figure F-3). The most important species are Avena barbata, Bromus diandrus, B. mollis, and B. rubens.
Community type 5 (Juniperus californica/Bromus diandrus-Lotus subpinnatus) is essentially a grassland with scattered shrubs (mean percent cover of 26 percent) dominated by Juniperus californica (the other three introduced grassland types lack an overstory). Mean percent grass cover is 76 percent, and the introduced species, Bromus diandrus and Avena barbata, are the most common. Internal percentage similarity between stands of this type is low relative to that of other community types on LLNL Site 300 and the number of species is intermediate (Table F-4). This type characteristically occurs at the base of north-facing canyon slopes with a clay-enriched soil (Table F-4), a combination of factors found only in the southern half of LLNL Site 300.
Community types 6, 7, and 8 form the bulk of the vegetation on LLNL Site 300. Minor changes in community composition were noted along edaphic and successional gradients. Community type 6 (Avena barbata-Brassica geniculata-Lotus subpinnatus) is typically found on ridgecrest or spur topographic positions; community type 7 (Avena barbata-Bromus diandrus) is an early successional type that develops in a variety of sites following soil disturbance; while community type 8 (Avena barbata-Triteleia laxa) is found on more mesic sites (such as north-facing slopes) or on sites where recent soil disturbance is not indicated.
Community type 6 stands have lower Brassica biomass than the annual grasslands described elsewhere in lowland California (Bell and Muller, 1973). Stands on LLNL Site 300 typically exhibit moderate species richness (an average of 15.7 species per stand) (Table F-4), as diversity is not being inhibited by strong Brassica competition. Observation of sites adjacent to LLNL Site 300 suggest that Brassica-dominated vegetation is better developed where heavy grazing is the rule. The lack of Brassica stands on LLNL Site 300 may correlate to the greater frequency of fires there than on comparable inner Coast Range sites (see section F.1.1.3). Internal percentage similarity between stands for community type 6 is high relative to that of other grassland communities (Table F-4).
Community type 7 vegetation is characterized by codominance of only two introduced grasses, Avena barbata and Bromus diandrus, whereas the other introduced grassland community types on LLNL Site 300 often have four or five codominants. This type is most extensive in areas of past or ongoing soil disturbance, such as those sections of the facility with dense road networks. Elsewhere in lowland California, Bromus diandrus dominated vegetation is a general indicator of severe disturbance in ruderal sites (Frenkel, 1970). Internal percentage similarity between stands and species richness is the lowest of all vegetation types at LLNL Site 300 (Table F-4).
Community type 8 vegetation exhibits high cover of the introduced grasses (89.0 percent, Table F-5) dominated by Avena barbata and Bromus mollis. Forb cover is 30 percent, with native species exhibiting slightly more cover than non-native species (Table F-5). Amsinckia intermedia and Erodium cicutarium are conspicuous forbs.
Native Grassland Communities
The four grassland community types, dominated by mostly native perennial grasses, exhibit low compositional variation relative to introduced grassland community types. Internal percentage similarity ranged from 63 to 72 percent (Table F-4). These types cover approximately 723 acres at LLNL Site 300.
Poa scabrella, the most characteristic dominant of native grassland communities on LLNL Site 300, displayed from 20 to 43 percent average cover by community. Community type 9 (Avena barbata-Poa scabrella-Erodium cicutarium) is transitional between annual and perennial grasslands, and is the only native grassland type with a higher percent cover of introduced species over native species (Table F-5). This type is found on a variety of sites and exposures, consistent with the interpretation that it represents an intermediate stage in the vegetation succession. Of the native grassland communities, community type 9 exhibits the lowest average species richness (Table F-4).
Community type 10 (Poa scabrella-Lasthenia minor) is an unusual vegetation unit in which native forbs comprise the majority of plant cover, 56 percent (Table F-5); with Lasthenia minor, Trifolium tridentatum, Orthocarpus purpurascens, Amsinckia intermedia, and L. californica the most important. Native grass cover averages about 47 percent followed by introduced grass at 22 percent and introduced forbs at 11 percent (Table F-5). This type occurs in clay soils at the base of slopes with a northeastern exposure (Table F-4).
North-facing toe slopes typically support community type 11 (Poa scabrella-Triteleia laxa) (Table F-4). Native grasses exhibit the highest percent cover at 56 percent (Table F-5), with Poa scabrella exhibiting its highest cover at 43 percent. Introduced grass covers 43 percent, with Avena barbata being the most common species.
Community type 12 (Poa scabrella-Sitanion jubatum community) has the fewest introduced annual species on LLNL Site 300. This type is characteristic of upper topographic positions on sandy soils, and is best developed on north-facing slopes (Table F-4). Cover of native grasses and forbs is 70 percent, while introduced species coverage is 34 percent (Table F-5). Some stands are mixtures of five native perennial grasses: Poa scabrella, Sitanion jubatum, Stipa pulchra, Koeleria nitida, Melica californica.
Stands of native grasslands on LLNL Site 300 are confined mainly to the northern half of the facility (Figure F-3). Occurrence of native grass–dominated vegetation correlates with annual controlled burning.
The native grass–dominated communities on LLNL Site 300 represent a unique resource. The plant species composition of this community type suggests two patterns of variation that may illuminate the structure of pristine California grasslands; (1) most investigators such as Heady (1977) and Barry (1972) agree with Clements (1920) that Stipa pulchra should dominate native grassland communities, as it often does on very sandy soils (Hull and Muller, 1977; Robinson, 1968); however, as discussed by Bartolome and Gemmil (1981), this conclusion may not be accurate. Dominance by Poa scabrella of LLNL Site 300 native grasslands specifically contradicts the notion that Stipa would dominate California grasslands in the absence of grazing and introduced annuals; and (2) the role of native forbs in native grassland communities has not received much study (Heady, 1977). Data from LLNL Site 300 suggest that both native annual and perennial forbs can assume an important role under the conditions of frequent burning and no grazing and thus may once have been important dominants or codominants of California grassland communities.
Seeps and Springs
Seeps and springs, rare on LLNL Site 300, are most frequently found where porous sandstone formations intersect gullies. Two seep plant community types were sampled in the 1986 survey. They are dominated by Elymus triticoides (see Figure G-8 in Appendix G for the location of spring-fed wetlands). Community type 13 (E. triticoides-Polypogon interruptus) is found where standing water is absent for extended periods, whereas community type 14 (E. triticoides-Typha latifolia) is found where standing water is often present.
Internal percentage similarity between stands of the two spring plant communities is high, about 75 percent (Table F-4). Mesophytes occurring as associates in these types include Juncus oxymeris, Elymus glaucus, Mimulus guttatus, and Distichilis spicata. Spring and seep vegetation is generally restricted to canyons on the southern half of LLNL Site 300.
Unusual or Restricted Communities
Vernal pools are a conspicuous, floristic unit in lowland grassland sites in California (Holland and Jain, 1977). Important dominants at the vernal pool at LLNL Site 300 are Boisduvalia glabella, Downingia insignis, Deschampsia danthonioides, and Plagiobothrys stipitatus. Figure G-8 in Appendix G shows the location of the vernal pool.
The northern riparian woodland community dominated by woody plants is rare at LLNL Site 300. Extensive Populus fremontii–dominated riparian vegetation occurs along Corral Hollow Creek adjacent to the facility. A wooded riparian shrub community characterized by Ribes divaricatum, Sambucus mexicana, Prunus virginiana, and Baccharis pilularis occurs north of Elk Ravine; while a riparian area dominated by Salix laevigata and S. mexicana occurs along the ravine.
Several relevés sampled onsite are typical of a distinctive habitat characteristic of the arid inner south Coast Range. Erosional patterns along gullies produce steep, often clay-rich badland topography dominated by a diverse mixture of native forbs. Such habitats, frequent in Corral Hollow and other surrounding areas, are poorly developed on LLNL Site 300. This type of habitat, however, was sampled at two sites in the extreme southwestern portion of the facility. Characteristic species of this habitat are Eriogonum angulosum, Amsinckia vernicosa, Mentzelia affinis, and Camissonia boothii.
Table F-1 Vascular Plants Observed at LLNL Site 300
| Scientific Name | Common Name |
| Pteridophyta Adiantaceae |
|
| Pellaea andromedaefolia Pityrogramma triangularis |
|
| Gymnospermae
Cupressaceae |
|
| Juniperus californica | California juniper |
| Angiospermae
Amaranthaceae |
|
| Amaranthus blitoides | Amaranth |
| Anacardiaceae | |
| Toxicodendron diversilobum | Poison oak |
| Apiaceae | |
| Apiastrum angustifolium Bowlesia incanaa Lomatium caruifoliuma Lomatium utriculatuma |
Wild celery |
| Sanicula crassicaulis | Sanicle |
| Sanicula bipinnata | Poison sanicle |
| Sanicula bipinnatifida | Purple sanicle |
| Torilis nodosab Yabea microcarpaa |
Hedge-parsley |
| Asclepiadacea | |
| Asclepias fascicularis | Milkweed |
| Asteraceae | |
| Achillea millefolium var. californica Achyrachaena mollis Agoseris grandiflora Agoseris heterophylla Artemisia californica Baccharis pilularis var. consanguinea Baccharis viminea Carduus pycnocephalusb Centaurea melitensisb Centaurea solstitialisb Cirsium proteanum |
Yarrow Blow-wives Mountain dandelion Mountain dandelion California sagebrush Chaparral broom Mule fat Italian thistle Tocalote Star thistle Thistle |
| Cirsium vulgareb
Conyza canadensis Coreopsis calliopsidea Ericameria linearifoliaa Erigeron inornatus var. angustatus Evax caulescensa Evax sparsifloraa Filago californicaa Gnaphalium palustre Grindelia camporum Gutierrezia bracteata Hemizonia kelloggii Hemizonia lobbii Heterotheca echioides Holocarpha obconica Hypochoeris glabrab Hypochoeris radicatab Lactuca serriolab Lagophylla glandulosaa Lasthenia californicaa Lasthenia chrysostomaa Lasthenia microglossaa Lasthenia minora Layia gaillardioidesa Layia platyglossa Logfia gallicaa,b Madia gracilis Malacothrix coulteri Matricaria matricarioides Micropus californicusa Microseris douglasii ssp. tenellaa Microseris lindleyi a Monolopia major a Pentachaeta alsinoidesa Picris echioidesb Psilocarphus brevissimusa Psilocarphus tenellusa Rafinesquia californicaa Senecio breweri Senecio vulgarisb Silybum marianumb Solidago canadensisb Sonchus asper b Sonchus oleraceusb Stylocline filagineaa,b |
Bull thistle Horseweed Coreopsis Fleabane Cubweed Gum-plant Snakeweed Tarweed Tarweed Golden aster Tarweed Cat's ear Cat's ear Prickly lettuce Tidy tips Gumweed Snake's head Pineapple weed Ox tongue Groundsel Groundsel Milk thistle Canada goldenrod Sow thistle Sow thistle |
| Stylocline gnaphalioidesa Taraxacum officinaleb Xanthium strumarium var. canadense |
Dandelion Cocklebur |
| Boraginaceae | |
| Amsinckia grandiflora Amsinckia intermedia Amsinckia menziesii Amsinckia tessellata Amsinckia vernicosa Cryptantha flaccidaa Cryptantha intermediaa Cryptantha microstachysa Heliotropium curassavicum var. oculatum Pectocarya penicillataa Plagiobothrys canescensa Plagiobothrys hystriculusa Plagiobothrys stipitatusa Plagiobothrys tenellusa Plagiobothrys tener a |
Large-flowered fiddleneck Fiddleneck Fiddleneck Fiddleneck Fiddleneck Seaside heliotrope |
| Crassicaceae | |
| Alyssum alyssoidesa,b Athysanus pusillusa Brassica geniculatab Brassica nigrab Capsella bursa-pastorisb Cardaria pubescensb Caulanthus flavescens Caulanthus lasiophyllus Descurainia sophiab Erysimum capitatum Lepidium nitidum var. insigne Nasturtium officinaleb Sisymbrium altissimum Sisymbrium officinaleb Thelypodium lemmonii a Thysanocarpus curvipes Thysanocarpus elegans |
Wild mustard Black mustard Shepherd's-purse Whitetop Prince's plume Prince's plume Tansy-mustard Wall flower Peppergrass Watercress Tumble-mustard Hedge-mustard Lace-pod Lace-pod |
| Callitrichaceae | |
| Callitriche vernaa | |
| Campanulaceae | |
| Downingia insignisa | |
| Caprifoliaceae | |
| Lonicera interrupta Sambucus mexicana |
Honeysuckle Elderberry |
| Caryophyllaceae | |
| Cerastium glomeratumb Herniaria cinereaa,b Loeflingia squarrosaa Minuartia californica Minuartia douglasii Sagina decumbens ssp. occidentalis Silene antirrhina Silene gallicab Spergularia marina Stellaria mediab Stellaris nitens |
Mouse-ear chickweed Sandwort Sandwort Pearlwort Catchfly Catchfly Sand-spurrey Common chickweed Chickweed |
| Chenopodiaceae | |
| Atriplex patula Atriplex semibaccatab Chenopodium californicum Chenopodium rubrumb Chenopodium vulvariab Monolepis nuttallianaa Salsola kali b |
Saltbush Australian saltbush Pigweed Pigweed Pigweed Russian thistle |
| Crassulaceae | |
| Crassula erecta | Pigmy-weed |
| Cucurbitaceae | |
| Marah fabaceus var. agrestis | Wild cucumber |
| Euphorbiaceae | |
| Eremocarpus setigerus
Euphorbia spathulata |
Turkey mullein Spurge |
| Fabaceae | |
| Astragalus asymmetricus Astragalus didymocarpus Lotus humistratus Lotus subpinnatus Lupinus albifrons Lupinus benthemii Lupinus bicolor var. umbellatus Lupinus densiflorus var. aureus Lupinus densiflorus var. palustris Lupinus densiflorus var. lacteus Lupinus succulentus Medicago polymorphab Melilotus albab Melilotus indicusb Trifolium albopurpureum Trifolium amplectens Trifolium dichotomum Trifolium gracilentum Trifolium microdon Trifolium oliganthum Trifolium tridentatum Vicia tetraspermab Vicia villosa ssp. variab |
Milkvetch Milkvetch Bird's foot trefoil Bird's foot trefoil Lupine Lupine Lupine Lupine Lupine Lupine Lupine Bur-clover White sweet-clover Sweet-clover Clover Clover Clover Clover Clover Clover Clover Vetch Winter vetch |
| Fagaceae | |
| Quercus douglasii Quercus lobata |
Blue oak Valley oak |
| Geraniaceae | |
| Erodium botrysb Eriodium brachycarpumb Erodium cicutarium ssp. jacquinianumb Erodium moschatumb Geranium molleb |
Storksbill Storksbill Storksbill Storksbill Cranesbill |
| Hippocastanaceae | |
| Aesculus californica | California buckeye |
| Hydrophyllaceae | |
| Eriodictyon californicum Nemophila menziesii Nemophila pedunculataa Phacelia ciliataa Phacelia distansa Phacelia douglasii a Phacelia imbricataa Phacelia tanacetifoliaa Pholistoma membranaceuma |
Yerba santa Baby blue-eyes |
| Lamiaceae | |
| Lamium amplexicaule
Marrubium vulgareb Pogogyne serpylloidesa Salvia columbariae Salvia mellifera Stachys albens Trichostema lanceolatum |
Henbit Horehound Sage Black sage Hedge-nettle Vinegar weed |
| Linaceae | |
| Hesperolinon californicum | Flax |
| Loasaceae | |
| Mentzelia affinis | Blazing-star |
| Loranthaceae | |
| Phoradendron villosum | Mistletoe |
| Malvaceae | |
| Eremalche parryi a Malva parviflorab Malvella leprosaa |
Cheeseweed |
| Oleaceae | |
| Forestiera neomexicana | Desert olive |
| Onagraceae | |
| Boisduvalia glabellaa
Camissonia boothii ssp. decorticans Camissonia cruciata Camissonia graciliflora Camissonia hirtella Clarkia affinisa Clarkia purpureaa Clarkia tembloriensisa Clarkia unguiculataa Epilobium canum ssp. mexicana Epilobium paniculatum |
Evening primrose Evening primrose Evening primrose Evening primrose Willow-herb Willow-herb |
| Orobanchaceae | |
| Orobanche californica
Orobanche uniflora var. minuta |
Broom-rape Broom-rape |
| Papaveraceae | |
| Eschscholzia californica Platystemon californicus Stylomecon heterophyllaa |
California poppy Cream cups |
| Plantaginaceae | |
| Plantago bigelovii Plantago erecta Plantago eriopoda Plantago lanceolatab |
Plantain Plantain Plantain Ribgrass |
| Plantanaceae | |
| Platanus racemosa | Sycamore |
| Polemoniaceae | |
| Allophyllum divaricatuma Eriastrum plurifloruma Gilia capitata var. abortanafoliaa Gilia capitata var. staminea a Gilia tricolor Linanthus bicolor a Linanthus dichotomus Microsteris gracilisa Navarretia nigellaeformisa |
Bird's eye gilia Evening snow |
| Polygonaceae | |
| Eriogonum angulosuma Eriogonum fasciculatum var. polifolium Eriogonum nuduma Eriogonum wrightii var. trachygonuma Polygonum aviculare Pterostegia drymarioidesa Rumux conglomeratusb Rumex crispusb Rumex salicifolius |
California buckwheat Common knotweed Sorrel Curly dock Sorrel |
| Portulacaceae | |
| Calandrinia ciliata Claytonia parviflora Claytonia perfoliata Claytonia spathulata var. exigua Claytonia spathulata var. tenuifolia |
Red maids Miner's lettuce Miner's lettuce Miner's lettuce Miner's lettuce |
| Primulaceae | |
| Androsace elongata ssp. acutaa Dodecatheon hendersonii |
Shooting star |
| Ranunculaceae | |
| Delphinium gypsophilum ssp. gypsophilum Delphinium hesperium Delphinium patens Ranunculus canus var. laetus Ranunculus hebecarpus Ranunculus sceleratus |
Larkspur Larkspur Larkspur Buttercup Buttercup Buttercup |
| Rosaceae | |
| Alchemilla arvensisa Heteromeles arbutifolia Prunus virginianavar. demissa Rubus leucodermis |
Christmas-berry Chock cherry Western raspberry |
| Rubiaceae | |
| Galium aparineb Galium porrigens var. tenue |
Bedstraw Bedstraw |
| Salicaceae | |
| Populus fremontii Salix laevigata |
Fremont cottonwood Willow |
| Saxifragaceae | |
| Lithophragma affinis Ribes divaricatum Ribes malvaceum Saxifraga californica |
Woodland-star Currant Chaparral currant Saxifrage |
| Scrophulariaceae | |
| Castilleja foliolosa Collinsia heterophylla Collinsia sparsifloraa Collinsia sparsiflora var. collinaa Linaria texana Mimulus aurantiacus Mimulus guttatus Mimulus latidens Mimulus nasutus Orthocarpus attenuatusa Orthocarpus purpurascens Scrophularia californica Veronica peregrina ssp. xalapensis |
Paint-brush Chinese houses Toad flax Monkey-flower Seep-spring monkey-flower Monkey-flower Monkey-flower Red owl clover Figwort Speedwell |
| Solanaceae | |
| Nicotiana bigelovii Nicotiana glaucab Solanum nodifloruma,b Solanum umbelliferuma |
Tobacco Tree tobacco |
| Uticaceae | |
| Hesperocnide tenellaa Urtica dioica var. holosericea Urtica urensb |
Nettle Dwarf nettle |
| Valerianaceae | |
| Plectritis ciliosaa
Plectritis congestaa |
|
| Violaceae | |
| Viola quercetorum | Violet |
| Monocotyledoneae | |
| Cyperaceae | |
| Cyperus eragrostis Eleocharis palustris Scirpus acutus Scirpus fluviatilis |
Umbrella-sedge Spike-rush Common tule River bullrush |
| Juncaceae | |
| Juncus balticus Juncus bufonis Juncus oxymeris Juncus patens Juncus tenuis var. congestus |
Baltic rush Toad rush Rush Rush Rush |
| Liliaceae | |
| Allium crispum Allium serratum Brodiaea elegans Calochortus clavatus ssp. palidus Calochortus venustus Chlorogalum pomeridianum Dichelostemma pulchella Fritillaria biflora Triteleia hyacinthina Triteleia elegansa Triteleia laxa |
Wild onion Wild onion Harvest brodiaea Mariposa lily Mariposa lily Soap plant Blue dicks Chocolate lily White hyacinth Grass nut |
| Lemnaceae | |
| Lemna minuta | Duckweed |
| Poaceae | |
| Alopecurus howellii
Avena barbatab Avena fatuab Bromus arenariusb Bromus diandrusb Bromus japonicus Bromus madritensisb Bromus marginatus Bromus molliformis Bromus mollisb Bromus rubensb Bromus sterilisb Bromus tectorum |
Foxtail Slender oat Wild oat Australian cress Ripgut brome Japanese cress Bromegrass Bromegrass Bromegrass Soft cress Foxtail Bromegrass Downy cress |
| Deschampsia danthonioides
Distichlis spicata var. stricta Elymus glaucus Elymus triticoides Hordeum depressum Hordeum geniculatum Hordeum leporinumb Hordeum pusillum Koeleria cristatab Koeleria gerardii b Koeleria nitida Lamarckia aureab Lolium multiflorumb Melica californica var. nevadensis Poa annuab Poa bulbosab Poa palustrisb Poa scabrella Polypogon interruptusb Polypogon monspeliensisb Schismus arabiscusa,b Sitanion hystrix Sitanion jubatum Stipa cernua Stipa pulchra Taeniatherum caput-medusaea,b Vulpia microstachys var. confusa Vulpia microstachys var. pauciflora Vulpia myurosb Vulpia octoflora |
Annual hairgrass Seashore saltgrass Blue wild-rye Alkalie wild-rye Barley Barley Barley Little barley Junegrass Junegrass Junegrass Goldentop Italian ryegrass Melicgrass Annual bluegrass Bulbous bluegrass Fowl bluegrass Pine bluegrass Ditch polypogon Rabbitfoot grass Squirreltail Big squirreltail Needlegrass Purple needlegrass Fescue Fescue Fescue Fescue |
| Potomogetonaceae | |
| Potamogeton crispus | Pondweed |
| Scheuchzeriaceae | |
| Lilaea scilloides | Flowering quillwort |
| Typhaceae | |
| Typha angustifolia Typha domingensis Typha latifolia |
Cattail Cattail Soft-flag |
a No common name.
b Introduced and naturalized vascular plant species.
Source: Taylor and Davilla, 1986b.
Table F-2 Constancy, Cover, and Importance Values for the More Important Plant Taxa at LLNL Site 300
| Species | Constancy | Cover | Importance Value | |
| Mean | Standard Error | |||
| Avena barbata | 87.62 | 36.66 | 2.17 | 124.28 |
| Bromus mollis | 73.85 | 7.27 | 0.72 | 81.12 |
| Bromus diandrus | 62.84 | 11.73 | 1.25 | 74.57 |
| Erodium cicutarium | 65.60 | 3.62 | 0.58 | 69.21 |
| Bromus rubens | 61.47 | 6.17 | 0.68 | 67.64 |
| Vulpia myuros | 55.96 | 5.66 | 0.68 | 61.62 |
| Poa scabrella | 38.53 | 7.98 | 1.33 | 46.52 |
| Trifolium tridentatum | 43.12 | 2.44 | 0.44 | 45.56 |
| Orthocarpus purpurascens | 39.91 | 0.89 | 0.39 | 40.80 |
| Lotus subpinnatus | 38.07 | 0.87 | 0.18 | 38.94 |
| Amsinckia intermedia | 36.70 | 1.26 | 0.26 | 37.95 |
| Gutierrezia bracteata | 27.52 | 1.43 | 0.31 | 28.95 |
| Brassica geniculata | 27.52 | 0.93 | 0.23 | 28.45 |
| Sanicula bipinnata | 26.61 | 0.23 | 0.07 | 26.83 |
| Grindelia camporum | 25.69 | 1.04 | 0.27 | 26.73 |
| Vulpia microstachys | 23.85 | 1.71 | 0.31 | 25.56 |
| Trifolium gracilentum | 22.94 | 1.33 | 0.37 | 24.26 |
| Triteleia laxa | 22.02 | 0.57 | 0.17 | 22.58 |
| Herniaria cinerea | 20.64 | 0.35 | 0.13 | 20.99 |
| Lupinus bicolor | 19.73 | 0.41 | 0.17 | 20.14 |
| Artemisia californica | 17.89 | 1.69 | 0.38 | 19.58 |
| Astragalus didymocarpus | 18.81 | 0.69 | 0.22 | 19.49 |
| Holocarpha obconica | 18.81 | 0.59 | 0.37 | 19.40 |
| Clarkia purpurea | 18.81 | 0.12 | 0.03 | 18.93 |
| Achillea millefolium | 16.97 | 0.47 | 0.12 | 17.44 |
| Amsinckia testillata | 15.14 | 0.13 | 0.04 | 15.27 |
| Galium aparine | 14.68 | 0.26 | 0.07 | 14.94 |
| Elymus triticoides | 9.63 | 3.25 | 0.96 | 12.88 |
| Eriogonum fasciculatum | 11.93 | 0.88 | 0.25 | 12.80 |
| Allium serra | 12.39 | 0.08 | 0.03 | 12.46 |
| Matricaria matricarioides | 11.93 | 0.35 | 0.19 | 12.28 |
| Marah fabaceus agrestis | 11.47 | 0.10 | 0.03 | 11.56 |
| Crassula erecta | 11.47 | 0.09 | 0.05 | 11.55 |
| Stipa pulchra | 10.55 | 0.70 | 0.23 | 11.25 |
| Stellaria nitens | 11.01 | 0.09 | 0.05 | 11.10 |
| Delphinum hesperium | 10.55 | 0.10 | 0.04 | 10.65 |
| Dichelostemma pulchellum | 10.58 | 0.03 | 0.01 | 10.57 |
| Hemizonia kelloggii | 10.09 | 0.47 | 0.30 | 10.56 |
| Claytonia perfoliata | 10.09 | 0.32 | 0.13 | 10.41 |
| Carduus pychnocephalus | 10.09 | 0.23 | 0.12 | 10.33 |
| Lupinus succulentus | 10.09 | 0.17 | 0.05 | 10.27 |
| Sonchus oleraceus | 10.09 | 0.04 | 0.02 | 10.13 |
| Senecio vulgaris | 10.09 | 0.01 | 0.00 | 10.11 |
| Eschscholzia californica | 9.63 | 0.23 | 0.11 | 9.86 |
| Collinsia heterophylla | 9.17 | 0.26 | 0.12 | 9.43 |
| Eriogonum nudum | 9.17 | 0.21 | 0.08 | 9.38 |
| Lupinus densiflorus lacteus | 9.17 | 0.14 | 0.04 | 9.31 |
| Chlorogalum pomeridianum | 8.72 | 0.15 | 0.06 | 8.86 |
| Sonchus aspera | 8.72 | 0.03 | 0.02 | 8.75 |
| Pterostegia drymerioides | 8.72 | 0.04 | 0.02 | 8.75 |
| Caulanthus lasiophyllus | 8.72 | 0.03 | 0.01 | 8.75 |
| Eremocarpus setigerus | 8.72 | 0.03 | 0.01 | 8.74 |
| Lasthenia californica | 8.26 | 0.28 | 0.16 | 8.53 |
| Eriogonum angulosum | 7.80 | 0.11 | 0.05 | 7.91 |
| Delphinium gypsophilum | 7.34 | 0.32 | 0.17 | 7.65 |
| Gilia tricolor | 7.34 | 0.10 | 0.05 | 7.44 |
| Plantago eriopoda | 7.34 | 0.05 | 0.03 | 7.39 |
| Gilia capitata abortanifolia | 7.34 | 0.03 | 0.01 | 7.37 |
| Juniperus californicus | 6.88 | 0.47 | 0.28 | 7.35 |
| Polypogon interruptus | 6.42 | 0.70 | 0.36 | 7.13 |
| Monolophia major | 6.88 | 0.24 | 0.13 | 7.12 |
| Erodium botrys | 6.88 | 0.10 | 0.05 | 6.98 |
| Silene antirrhinam | 6.88 | 0.10 | 0.04 | 6.98 |
| Brassica nigra | 6.88 | 0.08 | 0.05 | 6.96 |
| Bromus madritensis | 6.42 | 0.42 | 0.16 | 6.84 |
| Melica california nevadensis | 6.42 | 0.29 | 0.13 | 6.71 |
| Centaurea melatensis | 6.42 | 0.22 | 0.13 | 6.64 |
| Trifolium oliganthum | 6.42 | 0.13 | 0.05 | 6.55 |
| Stylocline gnaphalioides | 6.42 | 0.07 | 0.03 | 6.49 |
| Typha latifolia | 5.05 | 1.26 | 0.48 | 6.30 |
| Microseris lindleyi | 5.96 | 0.01 | 0.01 | 5.98 |
| Sitanion hystrix | 5.51 | 0.34 | 0.14 | 5.84 |
| Salvia mellifera | 5.05 | 0.68 | 0.26 | 5.72 |
| Mimulus guttatus | 5.51 | 0.20 | 0.12 | 5.70 |
| Microseris douglasii | 5.51 | 0.15 | 0.08 | 5.66 |
| Linanthus bicolor | 5.51 | 0.16 | 0.09 | 5.66 |
| Claytonia parviflora | 5.51 | 0.05 | 0.03 | 5.56 |
| Quercus douglasii | 5.05 | 0.50 | 0.20 | 5.55 |
| Logfia gallica | 5.51 | 0.04 | 0.02 | 5.55 |
| Calochortus invenustus | 5.51 | 0.02 | 0.01 | 5.52 |
| Hordeum leporinum | 5.05 | 0.12 | 0.06 | 5.16 |
| Amsinckia menziesii | 5.05 | 0.03 | 0.02 | 5.08 |
| Delphinium patens | 5.05 | 0.03 | 0.02 | 5.08 |
| Stylocline filaginea | 5.05 | 0.03 | 0.01 | 5.07 |
| Microsteris gracilis | 5.05 | 0.02 | 0.01 | 5.07 |
| Achyrachoena mollis | 4.59 | 0.22 | 0.21 | 4.81 |
| Silene gallica | 4.59 | 0.08 | 0.05 | 4.67 |
| Schismus arabicus | 4.59 | 0.07 | 0.03 | 4.65 |
Source: Taylor and Davilla, 1986a.
Table F-3 Plant Community Types at LLNL Site 300
| Plant Community Type | Major Plant Community Types |
| Coastal Sage Scrub | |
| Type 1 Type 2 Type 3 |
Artemisia californica-Salvia
mellifera/Herniaria cinerea
Artemisia californica/Bromus mollis Gutierrezia bracteata/Avena barbata |
| Oak Woodland | |
| Type 4 | Quercus douglasii/Avena barbata |
| Introduced Grasslands | |
| Type 5
Type 6 Type 7 Type 8 |
Juniperus californica/Bromus diandrus-Lotus
subpinnatus
Avena barbata-Brassica geniculata-Lotus subpinnatus Avena barbata-Bromus diandrus Avena barbata-Triteleia laxa |
| Native Grasslands | |
| Type 9
Type 10 Type 11 Type 12 |
Avena barbata-Poa scabrella-Erodium
cicutarium Poa scabrella-Lasthenia minor Poa scabrella-Triteleia laxa Poa scabrella-Sitanion jubatum |
| Seeps and Springs | |
| Type 13
Type 14 |
Elymus triticoidos-Polypogon interruptus Elymus triticoidos-Typha latifolia |
Source:Taylor and Davilla, 1986a.
Table F-4 Site Characteristics of Plant Community Types on LLNL Site 300
| Plant Community Typesa | Number of Species | Elevation (feet) | Mean Aspect | Typical Topographic Position | Typical Substrate/ Soil | Number of Species Per Stand | Mean Internal Percent Similarity Within Type | ||
| Mean ± S.E.b | Range | Mean ± S.E. | Range | ||||||
| Coastal Sage Scrub | |||||||||
| Type 1 | 14 | 1067±99 | 730–1460 | Southwest | Slopes | Sandstone rock | 23.4±2.3 | 10–35 | 66 |
| Type 2 | 9 | 978±72 | 780–1200 | Southwest | Gullies | Sandstone rock | 22.5±3.9 | 13–41 | 63 |
| Type 3 | 10 | 884±86 | 700–1240 | All exposures | Ridges | Conglomerate | 17.8±2.5 | 9–27 | 67 |
| Oak Woodland | |||||||||
| Type 4 | 8 | 1030±97 | 740–1400 | North & west | Steep slopes | Silty loam | 21.8±2.2 | 15–31 | 54 |
| Introduced Grassland | |||||||||
| Type 5 | 5 | 1018±32 | 900–1080 | North | Lower slopes | Clay loams | 17.2±1.1 | 14–20 | 52 |
| Type 6 | 27 | 1148±127 | 680–1675 | South | Ridges/spurs | Rocky-sandy | 15.7±2.3 | 9–32 | 68 |
| Type 7 | 34 | 1212±93 | 840–1600 | Various | Lower slopes | Loams | 14.0±2.7 | 3–30 | 51 |
| Type 8 | 48 | 1148±106 | 740–1700 | North | Toe slopes | Clay | 16.9±2.7 | 6–34 | 58 |
| Native Grassland | |||||||||
| Type 9 | 15 | 1244±112 | 790–1680 | Various | Various | Sandy clay | 15.8±2.0 | 9–23 | 63 |
| Type 10 | 7 | 1185±75 | 1060–1560 | Northeast | Toe slopes | Clay | 18.0±2.6 | 11–25 | 65 |
| Type 11 | 13 | 1185±116 | 830–1485 | North | Toe slopes | Clay loam | 21.6±3.9 | 11–39 | 66 |
| Type 12 | 7 | 1212±88 | 900–1420 | North | Upper slopes | Sandy loam | 22.7±2.4 | 14–32 | 72 |
| Seeps and Springs | |||||||||
| Type 13 | 5 | 838±48 | 650–940 | All aspects | Ravines | Silty sand | 16.2±4.8 | 10–36 | 75 |
| Type 14 | 12 | 985±99 | 700–1540 | All aspects | Springs | Silty clays | 14.0±2.9 | 7–32 | 76 |
a Corresponds with plant community types
listed in Table F-3.
b S.E. = Standard error. Source: Taylor
and Davilla, 1986a.
Table F-5 Percent Cover by Life-Form for Community Types Found on LLNL Site 300a
| Plant CommunityType b | Trees | Shrubs | Grasses | Forbs | Grass and Forbs | ||||||
| Total | Native | Introduced | Total | Native | Introduced | Total | Native | Introduced | |||
| Coastal Sage Scrub | |||||||||||
| Type 1 Type 2 Type 3 |
0 0 0 0 |
43.8 23.4 13.9 |
42.9 63.9 57.6 |
5.9 2.2 0.3 |
37.0 61.7 57.3 |
9.7 8.7 18.3 |
6.0 3.0 6.8 |
3.7 5.7 11.5 |
52.6 72.6 75.9 |
11.9 5.2 7.1 |
40.7 67.4 68.8 |
| Oak Woodland | |||||||||||
| Type 4 | 13.0 | 0.3 | 112.8 | 10.5 | 102.3 | 10.0 | 7.9 | 2.1 | 122.8 | 18.4 | 104.4 |
| Introduced Grasslands | |||||||||||
| Type 5 Type 6 Type 7 Type 8 |
0 0 0 0 |
25.8 0.5 0.7 0.5 |
76.2 94.4 96.5 97.3 |
0.0 5.8 3.8 8.3 |
76.2 88.6 92.7 89.0 |
3.8 23.8 10.4 30.3 |
1.8 17.4 6.1 16.0 |
2.0 6.4 4.3 14.3 |
80.0 118.2 106.9 127.6 |
1.8 23.2 9.9 24.3 |
78.2 95.0 97.0 103.3 |
| Native Grasslands | |||||||||||
| Type 9 Type 10 Type 11 Type 12 |
0 0 0 0 |
0.0 0.0 0.0 0.0 |
101.1 68.6 98.8 81.3 |
24.2 47.1 56.3 49.4 |
76.9 21.5 42.9 31.9 |
24.6 66.7 43.1 22.3 |
19.2 56.1 32.3 20.5 |
5.4 10.6 10.8 1.8 |
125.7 135.3 141.9 103.6 |
43.4 103.2 88.6 69.9 |
82.3 32.1 53.7 33.7 |
| Seeps and Springs | |||||||||||
| Type 13 Type 14 |
0 0 |
0.0 0.0 |
100.0 84.8 |
61.3 52.8 |
38.7 32.0 |
3.1 18.8 |
0.3 11.4 |
2.8 7.4 |
103.1 103.6 |
61.6 64.2 |
41.5 39.4 |
a Percent cover may be greater than 100 percent due to overlap of vegetation of different heights.
b Corresponds with plant community types listed in Table F-3.
Source: Taylor and Davilla, 1986a.
F.1.1.3 Impacts of Current Operations
Disturbances to vegetation on LLNL Site 300 from current operations are much less than the impacts of land use practices on private lands nearby, where upland and riparian plant communities have been altered by grazing and other agricultural activities. Impacts at LLNL Site 300, however, do include the direct loss of vegetation by construction of facilities such as testing sites, firing tables, closed landfills, wastewater facilities, maintenance buildings, security facilities, fences, and roads. These disturbed areas, totaling about 220 acres, are almost devoid of vegetation. Facilities in the southern half of the site have disturbed mostly introduced grassland plant communities. The generally small facilities in the northern half of the site have not significantly disturbed large areas of land even when adjacent to native grassland habitats.
Other operational practices on LLNL Site 300 include the exclusion of grazing and other agricultural practices; construction and maintenance of fire roads and breaks; vegetation management using controlled burning for fire control and weed control along roads, power poles, and security fence perimeters using herbicides and disking; and minor construction in or adjacent to existing facilities.
Because no livestock grazing has been permitted since 1953, baseline comparisons of the flora on LLNL Site 300 with that of neighboring, grazed parcels show a greater complement of native grasses and herbs on LLNL Site 300. Slopes and substrates show less instability and erosion, probably the result of a more stable plant cover and the retention of soil-binding native plant species.
Most of the property has not been disked or dry-farmed since it was acquired. The limited disking for fire control has had a minor impact on the overall vegetation of LLNL Site 300. Currently, only a narrow swath of land is disked along the northern, and part of the western and eastern boundaries of the site. This perimeter disking is done in May, providing added protection during controlled burning against the possible escape of fire to offsite properties. The disked areas favor establishment and maintenance of introduced grasses and moderate cover of tarweeds (Holocarpha obconica, Hemizonia kelloggii, H. lobbii).
For weed and fire control, herbicides such as Roundup® and Amitrol® are applied in the fall and winter along paved roads, and Hyvar-X® is used around security fences, power poles, and on a 90-ft-wide strip surrounding Building 829, a high explosives burn unit. Herbicides have favored the introduction and maintenance of ruderal type vegetation in these areas (Frenkel, 1970).
Controlled burning is conducted annually as a means of wildfire control. LLNL Site 300 began a burning program in the northeastern half of the site in the 1950s and has continued the program annually since 1960. All areas of the site have been burned at least once since 1960. The northern half of the site is burned annually, whereas the southern half has been burned only four times since 1960 (and portions of sections 21 and 28 have been burned twice). Burning typically begins about the middle of May and lasts several weeks, though this schedule depends on the length of the growing season and amount of rainfall.
Fire limits the development of coastal sage scrub vegetation on LLNL Site 300 to rocky sites, and also influences the composition and distribution of native grasslands. Restriction of coastal sage scrub to rocky sites is associated with reduced dry grass fuel levels and increased patchiness of all fuels. Although vegetation in rocky areas is subject to local fires, the rocks offer some protection and the vegetation may not be burned in every fire. Shrubs that would otherwise be eliminated then increase in importance. Native grassland communities on LLNL Site 300 occur almost exclusively in areas with annual controlled burning.
Remarkably little quantitative ecological literature exists on the role of fire in establishing and restoring native grassland communities in California (Heady, 1977); however, both Barry (1972) and Heady (1972) indicate that frequent fire is required to establish and maintain grasslands dominated by native grasses in lowland California. This conclusion is borne out by grassland vegetation found at LLNL Site 300. Figure F-4 shows the distribution of native grassland vegetation in relation to the limits of annual controlled fires, with a high correspondence between them. Not all plant communities within the perimeter of annual controlled fire on LLNL Site 300 are native grass–dominated, but the lack of introduced grasses on some habitats strongly correlates with the pattern and frequency of fires (Taylor and Davilla, 1986a).
A comprehensive inventory of native grasslands has not been conducted for California. Notably, Barry (1972) did not mention the presence of native grasslands in the vicinity of LLNL Site 300. An estimated 723 acres of native grassland communities occur on LLNL Site 300. Using the evaluation criteria established by Barry (1972), LLNL Site 300 could be judged one of the largest native grasslands of this kind currently known in California.
F.1.2 Fauna
The fauna at the study sites have been described in a number of previous reports (DOE, 1982; UC, 1987; Orloff, 1986; Environmental Science Associates, 1990) and in surveys conducted in 1991 for this EIS/EIR. The 1991 surveys were conducted to assess the status of threatened and endangered species and other sensitive species, and to map wetlands. The surveys were not conducted to provide comprehensive fauna species list or assess the ecological characteristics of nonthreatened or endangered species; nonetheless, all species of wildlife observed were noted, resulting in a comprehensive inventory of amphibians, reptiles, and mammals, especially at LLNL Site 300 where the majority of the field work occurred. Many species of breeding birds were noted because most of the field work occurred during the nesting season. Observation of additional migrant and wintering species would be expected if surveys occurred during other seasons.
F.1.2.1 Methods
Species of wildlife observed during field work were recorded when possible. In addition, during threatened and endangered surveys, sensitive species surveys, and wetlands surveys notes were kept on species of amphibians, reptiles, birds, and mammals observed. Notes on all wildlife species observed were also kept during night spotlighting, scent station maintenance, and small mammal trapping.
F.1.2.2 Results
Amphibians and Reptiles
A total of 20 species of amphibians and reptiles including two subspecies of the whipsnake were observed in 1986 (Orloff, 1986) and 1991 at LLNL Site 300; three species were recorded at the LLNL Livermore site and SNL, Livermore (Table F-6). The scarcity of permanent water limits the potential for the study sites to support more than a few species of amphibians. Ponds occur along the perimeter of LLNL Site 300, and some of the drainages onsite contain aquatic vegetation supported by underground springs and seeps. Two species of salamanders were observed at LLNL Site 300: the California slender salamander (Batrachoseps attenuatus) and the tiger salamander (Ambystoma tigrinum californiense). Frog and toad species known to occur on site are the western toad (Bufo boreas), Pacific treefrog (Hyla regilla), and the red-legged frog (Rana aurora draytoni ). The Pacific treefrog was the only amphibian species recorded at the LLNL Livermore site and SNL, Livermore.
Conditions are far more favorable for reptiles than amphibians at LLNL Site 300. Grassland provides ideal habitat for racers (Coluber constrictor) and gopher snakes (Pituophis melanoleucus). Rock sites provide suitable habitat for such species as the western fence lizard (Sceloporus occidentalis), western skink (Eumeces skiltonianus), common kingsnake (Lampropeltis getulus), and the western rattlesnake (Crotalus viridis). The western rattlesnake have been observed to be widespread and abundant in all habitats on LLNL Site 300. Seeps and springs provide excellent habitat for the northern alligator lizard (Gerrhonotus coeruleus). Side-blotched lizards (Uta stansburiana) and California horned lizards (Phrynosoma coronatum frontale), more commonly found in southern California, frequent areas with more open vegetation and sandy soils. The western fence lizard and gopher snake were the only two reptile species observed at the LLNL Livermore site and SNL, Livermore.
The California Department of Fish and Game Ecological Preserve along the Corral Hollow drainage adjacent to LLNL Site 300 was established to protect the unusual diversity of reptiles and amphibians. Species more typical of southern deserts have been found, including the glossy snake (Arizona elegans), long-nosed snake (Rhinocheilus lecontel ), and the coachwhip (Masticophis flagellum). Of the three species, only the coachwhip has been observed onsite.
One federal candidate species and state species of special concern, the red-legged frog, was recorded at LLNL Site 300 in 1991. A state species of special concern, the California horned lizard was also observed. Details regarding the results of surveys for these species are provided in Section F.2.
Birds
A total of 75 species of birds were observed at the study sites; this includes 70 species observed at LLNL Site 300, and 31 species at the LLNL Livermore site and SNL, Livermore (Table F-7). These species were recorded during springtime surveys for threatened and endangered species in 1986 (Orloff, 1986) and 1991, and concurrent with 1991 wetland surveys.
LLNL Site 300, with its interspersion of several different habitats and its abundance of seeds and insects, supports a variety of birds. The western meadowlark (Sturnella neglecta), horned larks (Eremophila alpestris), and savannah sparrow (Passerculus sandwichensis) were the most common small birds seen throughout the open grassland areas. Vegetation at springs and seeps provides nesting habitat for red-winged blackbirds (Agelaius phoeniceus) and tricolored blackbirds (A. tricolor). Tricolored blackbirds were observed onsite in 1986 but not in 1991 (see section F.2 for more details regarding the tricolored blackbird). These water sources attract a greater number of birds than normally found in the adjacent grasslands. For example, the mourning dove (Zenaida macroura), cliff and barn swallow (Hirundo pyrrhonota and H. rustica), and California quail (Callipepla californica) all require water daily.
Oak woodlands and a few cottonwoods provide nesting habitat for the western kingbird (Tyrannus verticalis), northern oriole (Icterus galbula), loggerhead shrike (Lanius ludovicianus), and American goldfinch (Carduelis tristis). Coastal sage scrub supports the scrub jay (Aphelocoma coerulescens), Anna's hummingbird (Calypte anna), rufous-crowned sparrow (Aimophila ruficeps), and white-crowned sparrow (Zonotrichia leucophrys). Ecotones of sage scrub and grassland provide ideal habitat for the mourning dove, California quail, lazuli bunting (Passerino amoena), and lark sparrow (Chondestes grammacus). Rocky outcrops and cliffs provide breeding sites for white-throated swift (Aeronautes saxatalis), cliff swallow, Say's phoebe (Sayornis saya), and rock wren (Salpinctes obsoletus).
LLNL Site 300 also supports a population of nesting raptors. Several great horned owl (Bubo virginianus) and barn owl (Tyto alba) nests were found on rock ledges of steeper cliffs. The great horned owl was recorded nesting onsite in 1986 and 1991 while the barn owl was recorded only in 1986. The cliffs onsite may also be suitable for golden eagles (Aquila chrysaetos) and prairie falcons (Falco mexicanus), although no nests were observed. Red-tailed hawk (Buteo jamaicensis) nests were found in 1986 and 1991. This species nested in large trees and on a utility pole in 1991. Areas with taller grasses may also allow ground-nesting raptors such as the northern harrier (Circus cyaneus) and short-eared owl (Asio flammeus) to successfully breed onsite (Orloff, 1986); however, these species were not observed to nest onsite in 1991.
Six sensitive raptor species were observed onsite during either the 1986 or the 1991 field survey: burrowing owl (Athene cunicularia), short-eared owl, golden eagle, northern harrier, black-shouldered kite (Elanus caeruleus), and prairie falcon. These species are of concern to the federal and/or state government, and are discussed in the biological assessment (section F.2).
Bird species nesting at the LLNL Livermore site and SNL, Livermore include those recorded in the building areas, the security zone, and Arroyo Seco. Species nesting in the builtup area are those typical of suburban areas, and include the killdeer (Charadrius vociferus), rock dove (Columbia livia), scrub jay, American crow (Corvus brachyrhynchos), American robin (Turdus migratorius), European starling (Sturnus vulgaris), house finch (Carpodacus mexicanus), and house sparrow (Passer domesticus). Species observed in the grass–dominated security zones include the western kingbird (Tyrannus verticalis), horned lark, and western meadowlark. Species recorded from the wooded portion of Arroyo Seco were the mourning dove, acorn woodpecker (Melanerpes formicivorus), western wood pewee (Canotopus sordidulus), plain titmouse (Parus inornatus) and northern oriole. The only raptors observed at these sites were the turkey vulture (Cathartes aura), red-tailed hawk, and barn owl.
Mammals
A total of 26 species of mammals were recorded during threatened and endangered species surveys in 1986 (Orloff, 1986) and 1991. All the species were seen at LLNL Site 300, and 10 species were observed at the LLNL Livermore site and SNL, Livermore (Table F-8). The investigation included ground surveys in all open areas, night spotlighting, establishment of scent stations, and small mammal trapping.
Productive and diverse grasslands on LLNL Site 300 support an abundance of rodents and lagomorphs (rabbits and hares). Conditions are ideal for California ground squirrels (Spermophilus beecheyi ) in the northern portion of LLNL Site 300 where the terrain is less rugged. Other common rodents include the house mouse (Mus musculus), deer mouse (Peromyscus maniculatus), Heermann's kangaroo rat (Dipodomys heermanni ), valley pocket gopher (Thomomys bottae) and, in the higher grass cover, the California vole (Microtus californicus) and western harvest mouse (Reithrodontomys megalotis). Lagomorphs such as black-tailed hares (Lepus californicus) and desert cottontails (Sylvilagus audubonii ) are also widespread and abundant, with the latter tending to occupy areas with more cover.
Rocky areas with associated coastal sage scrub support the California pocket mouse (Perognathus californicus) and desert woodrat (Neotoma lepida). The woodrat occurs primarily in rocky areas in this northern extreme of its range.
Many mammalian predators are supported by the rich prey base. Grassland predators include the long-tailed weasel (Mustela frenata), western spotted skunk (Spilogale gracilis), striped skunk (Mephitis mephitis), coyote (Canis latrans), badger (Taxidea taxus), and bobcat (Lynx rufus). Only the badger is restricted to open grasslands. Red foxes (Vulpes vulpes), which have been reported from nearby areas to the east and north of the site (California Department of Fish and Game, 1983; Bio-Tech, 1983), have greatly expanded their range in the Central Valley in recent years. They show a preference for more disturbed areas, often denning in roadside culverts, and were observed near LLNL Site 300 in 1991. Sage scrub, wooded, and riparian habitats attract other mammalian predators not normally found in grasslands including bobcat, gray fox (Urocyon cinereoargenteus), raccoon (Procyon lotor), and mountain lion (Felis concolor). Although these habitats are preferred, they are relatively limited on LLNL Site 300; consequently, grassland areas are used as well. Only minor areas of riparian vegetation are associated with the seeps and springs that occur along the canyon bottoms. Black-tailed deer (Odocoileus hemionus) prefer these habitats but are frequently seen in the open grasslands.
The most commonly recorded mammal species during 1991 night spotlighting at LLNL Site 300 were the desert cottontail, Heermann's kangaroo rat, black-tailed deer, and black-tailed hare (Table F-9). Feral house cat (Felis domesticus) tracks were relatively frequent at the scent stations but only one was observed during night spotlighting. Medium-sized predators recorded included the coyote and bobcat.
Small-mammal trapping took place May 5 to 8, 1986, at LLNL Site 300 and totaled 415 trap nights (a trap night equals one trap set out for one night). Species trapped included the western harvest mouse, house mouse, deer mouse, desert woodrat, and Heermann's kangaroo rat (Table F-10) with deer mice being the most common species captured.
Surveys were conducted in 1991 at the LLNL Livermore site, LLNL Site 300, and SNL, Livermore for one endangered species, the San Joaquin kit fox (Vulpes macrotis mutico), and at LLNL Site 300 for two federal candidate species, the San Joaquin pocket mouse (Perognathus inornatus) and the riparian woodrat (Neotoma fuscipes riparia). Of the three species only the San Joaquin pocket mouse was observed; the San Joaquin kit fox was not observed onsite. Results of surveys for these species are provided in section F.2.
A total of 10 species of mammals were recorded at the LLNL Livermore site and SNL, Livermore (Table F-8). Common species recorded during night spotlighting and at scent stations were the feral house cat, desert cottontail, black-tailed hare, red fox, and gray fox. In addition, the Virginia opossum was recorded frequently at the scent stations (Table F-9).
Table F-6 Amphibian and Reptile Species Observed at the LLNL Livermore Site, LLNL Site 300, and SNL, Livermore
| Species | Study Site | ||
| Scientific Name | Common Name | LLNL Site 300 | LLNL Livermore Site and SNL, Livermore |
| Ambystoma tigrinum californiense | Tiger salamander | X | |
| Batrachoseps attenuatus | California slender salamander | X | |
| Bufo boreas | Western toad | X | |
| Hyla regilla | Pacific treefrog | X | X |
| Rana aurora draytoni | Red-legged frog | X | |
| Sceloporus occidentalis | Western fence lizard | X | X |
| Sceloporus graciosus | Sagebrush lizard | X | |
| Uta stansburiana | Side-blotched lizard | X | |
| Phrynosoma coronatum frontale | California horned lizard | X | |
| Eumeces skiltonianus | Western skink | X | |
| Eumeces gilberti | Gilbert's skink | X | |
| Cnemidophorus tigris | Western whiptail | X | |
| Gerrhonotus coeruleus | Northern alligator lizard | X | |
| Coluber constrictor | Racer | X | |
| Masticophis flagellum | Coachwhip | X | |
| Masticophis lateralis euryxanthus | Alameda whipsnake | X | |
| Masticophis lateralis lateralis | California whipsnake | X | |
| Pituophis melanoleucus | Gopher snake | X | X |
| Lampropeltis getulus | Common king snake | X | |
| Thamnophis sirtalis | Common garter snake | X | |
| Crotalus viridis | Western rattlesnake | X | |
Table F-7 Bird Species Observed at the LLNL Livermore Site, LLNL Site 300 and SNL, Livermore
| Species | Study Site | ||
| Scientific Name | Common Name | LLNL Site 300 | LLNL Livermore Site and SNL, Livermore |
| Bucephala clangula | Common goldeneye | X | |
| Anas platyrhynchos | Mallard | X | |
| Rallus limicola | Virginia rail | X | |
| Ardea herodias | Great blue heron | X | |
| Butorides striatus | Green-backed heron | X | |
| Cathartes aura | Turkey vulture | X | X |
| Elanus caeruleus | Black-shouldered kite | X | |
| Circus cyaneus | Northern harrier | X | |
| Buteo jamaicensis | Red-tailed hawk | X | X |
| Accipiter cooperii | Cooper's hawk | X | |
| Aquila chrysaetos | Golden eagle | X | |
| Falco sparverius | American kestrel | X | |
| Falco mexicanus | Prairie falcon | X | |
| Callipepla californica | California quail | X | |
| Charadrius vociferus | Killdeer | X | X |
| Columba livia | Rock dove | X | X |
| Zenaida macroura | Mourning dove | X | X |
| Geococcyx californianus | Greater roadrunner | X | |
| Tyto alba | Barn owl | X | X |
| Bubo virginianus | Great horned owl | X | |
| Athene cunicularia | Burrowing owl | X | |
| Asio flammeus | Short-eared owl | X | |
| Chordeiles minor | Common nighthawk | X | |
| Aeronautes saxatalis | White-throated swift | X | |
| Calypte anna | Anna's hummingbird | X | |
| Selasphorus rufus | Rufous hummingbird | X | |
| Selasphorus sasin | Allen's hummingbird | X | |
| Melanerpes formicivorus | Acorn woodpecker | X | X |
| Colaptes auratus | Northern flicker | X | X |
| Tyrannus verticalis | Western kingbird | X | X |
| Myiarchus cinerascens | Ash-throated flycatcher | X | |
| Contopus sordidulus | Western wood-pewee | X | X |
| Empidonax difficilis | Western flycatcher | X | |
| Sayornis nigricans | Black phoebe | X | |
| Sayornis saya | Say's phoebe | X | |
| Eremophila alpestris | Horned lark | X | X |
| Hirundo pyrrhonota | Cliff swallow | X | |
| Hirundo rustica | Barn swallow | X | X |
| Aphelocoma coerulescens | Scrub jay | X | X |
| Corvus brachyrhynchos | American crow | X | X |
| Corvus corax | Common raven | X | X |
| Parus inornatus | Plain titmouse | X | X |
| Salpinctes obsoletus | Rock wren | X | |
| Turdus migratorius | American robin | X | |
| Catharus guttatus | Hermit thrush | X | |
| Mimus polyglottos | Northern mockingbird | X | X |
| Anthus rubescens | American pipit | X | |
| Lanius ludovicianus | Loggerhead shrike | X | X |
| Sturnus vulgaris | European starling | X | X |
| Vireo huttoni | Hutton's vireo | X | |
| Dendroica petechia | Yellow warbler | X | |
| Dendroica coronata | Yellow-rumped warbler | X | |
| Oporornis tolmiei | MacGillivray's warbler | X | |
| Wilsonia pusilla | Wilson's warbler | X | |
| Piranga ludoviciana | Western tanager | X | |
| Passerina amoena | Lazuli bunting | X | |
| Pheucticus melanocephalus | Black-headed grosbeak | X | |
| Pipilo crissalis | California towhee | X | |
| Aimophila ruficeps | Rufous-crowned sparrow | X | |
| Pooecetes grammineus | Vesper sparrow | X | |
| Chondestes grammacus | Lark sparrow | X | |
| Passerculus sandwichensis | Savannah sparrow | X | |
| Passerella iliaca | Fox sparrow | X | |
| Melospiza melodia | Song sparrow | X | |
| Zonotrichia atricapilla | Golden-crowned sparrow | X | |
| Zonotrichia leucophrys | White-crowned sparrow | X | |
| Agelaius phoeniceus | Red-winged blackbird | X | X |
| Agelaius tricolor | Tricolored blackbird | X | |
| Sturnella neglecta | Western meadowlark | X | X |
| Euphagus cyanocephalus | Brewer's blackbird | X | X |
| Molothrus ater | Brown-headed cowbird | X | |
| Icterus galbula | Northern oriole | X | X |
| Carpodacus mexicanus | House finch | X | X |
| Carduelis tristis | American goldfinch | X | X |
| Passer domesticus | House sparrow | X | X |
Table F-8 Mammal Species Observed at the LLNL Livermore Site, LLNL Site 300, and SNL, Livermore
| Species | Study Site | ||
| Scientific Name | Common Name | LLNL Site 300 | LLNL Livermore Site and SNL, Livermore |
| Didelphis virginiana | Virginia opossum | X | X |
| Tadarida brasiliensis | Mexican free-tailed bat | X | |
| Sylvilagus audubonii | Desert cottontail | X | X |
| Lepus californicus | Black-tailed hare | X | X |
| Spermophilus beecheyi | California ground squirrel | X | X |
| Thomomys bottae | Valley pocket gopher | X | |
| Perognathus californicus | California pocket mouse | X | |
| Perognathus inornatus | San Joaquin pocket mouse | X | |
| Dipodomys heermanni | Heermann's kangaroo rat | X | |
| Reithrodontomys megalotis | Western harvest mouse | X | |
| Peromyscus maniculatus | Deer mouse | X | |
| Neotoma lepida | Desert woodrat | X | |
| Microtus californicus | California vole | X | |
| Mus musculus | House mouse | X | |
| Canis latrans | Coyote | X | X |
| Vulpes vulpes | Red fox | X | X |
| Urocyon cinereoargenteus | Gray fox | X | X |
| Procyon lotor | Raccoon | X | X |
| Mustela frenata | Long-tailed weasel | X | |
| Taxidea taxus | Badger | X | |
| Spilogale gracilis | Western spotted skunk | X | |
| Mephitis mephitis | Striped skunk | X | X |
| Felis concolor | Mountain lion | X | |
| Felis domesticus | Feral house cat | X | X |
| Lynx rufus | Bobcat | X | |
| Odocoileus hemionus | Black-tailed deer | X | |
Table F-9 Species and Numbers of Individual Mammals Recorded During Night Spotlighting and at Scent Stations at the LLNL Livermore Site, LLNL Site 300, and SNL, Livermore in April, May, and June 1991
| Species | Spotlighting | Scent Station | ||
| LLNL Site 300a | LLNL Livermore Site and SNL, Livermore b | LLNL Site 300c | LLNL Livermore Site and SNL, Livermore c | |
| Virginia opossum | --- | --- | --- | 8 |
| Desert cottontail | 32 | 31 | 1 | --- |
| Black-tailed hare | 14 | 24 | --- | --- |
| Heermann's kangaroo rat | 32 | --- | --- | --- |
| California ground squirrel | --- | --- | 7 | --- |
| Coyote | 9 | 1 | --- | --- |
| Red fox | --- | 24 | --- | 7 |
| Gray fox | --- | 3 | --- | 26 |
| Raccoon | --- | 1 | --- | 1 |
| Long-tailed weasel | --- | --- | 1 | --- |
| Badger | --- | --- | 1 | --- |
| Western spotted skunk | --- | --- | 2 | --- |
| Striped skunk | 1 | 1 | --- | 4 |
| Bobcat | 2 | --- | --- | --- |
| Feral house cat | 1 | 37 | 14 | 19 |
| Black-tailed deer | 22 | --- | --- | --- |
a Six surveys from April 30 through May
8, 1991.
bNine surveys from May 10 through June 5,
1991.
cSix surveys from April 30 through May 9,
1991.
Table F-10 Small Mammal Trapping Results at LLNL Site 300 During May 1986
| Trap Location | Trap Habitat | Trap Nights | Number and Species | Success |
| Drop tower | Annual grasslands low to high vegetation density | 150 | 5 deer mice | 3% |
| Northwest corner | Annual grassland, sandy soils, low to high vegetation density | 200 | 7 deer mice
2 western harvest mice 1 house mouse |
5% |
| Facility 845 | Perennial grassland, medium to high vegetation density | 60 | 2 deer mice
1 western harvest mouse 1 Heermann's kangaroo rat |
7% |
| Do-all Road | Rocky outcrops | 5 | 1 desert woodrat | 20% |
| Total: | 415 | 20 | 5% | |
Source: Orloff, 1986.
F.1.2.3 Impacts of Current Operations
Program activities for LLNL Site 300 are discussed in section 3.1 and Appendix A. The activities discussed in section F.1.1 for vegetation would also impact wildlife at LLNL Site 300, as would vehicle traffic, fencing of facilities, explosives testing, surface impoundments, and the sewage lagoon.
Controlled Burn
The controlled burn generally has a positive effect on wildlife. Animals living underground (ground squirrels, burrowing owls, and pocket mice) or animals such as lizards, which escape into crevices and holes, are unlikely to be directly affected by fast-moving grass fires. Rodents inhabiting this region are adapted to periodic grass fires, so burning should not have an adverse impact on them. Burns stimulate new vegetative growth and create range conditions that probably support a greater diversity of wildlife than if the area were not burned. These newly burned areas provide excellent foraging habitat for open-country raptors. Annual burning provides a diversity of habitat for ground-nesting bird species, including raptors, but also may result in mortality for the young before they have fledged.
Lack of Livestock Grazing
LLNL Site 300, which is surrounded on three sides by heavily grazed lands, has not been grazed for almost 40 years. Studies have suggested that grazing may increase habitat stability for rodent species including the California ground squirrel (Balestreri, 1981; Laughrin, 1970; Jensen, 1972; Orloff, in press). Other studies have indicated that heavy grazing lowers the density of some rodent species such as kangaroo rats and pocket mice (O'Farrell and McCue, 1981; O'Farrell et al., 1981). The exclusion of grazing on LLNL Site 300 appears to have resulted in an abundance of several granivorous rodents (e.g., kangaroo rats and pocket mice) that no longer need to compete with livestock for food. Despite the lack of grazing, however, ground squirrel populations have remained plentiful in the flatter, northern half of the site. Many herbivorous animals generally prefer perennial grasses to the less nutritious annuals (Sampson et al., 1951). These perennial grasslands have developed in areas where grazing has been excluded and where annual controlled burns occur.
The exclusion of livestock grazing may have a mixed effect on the bird population. Ground-nesting species including raptors probably benefit from the resultant tall grass. Foraging suitability for other open-country raptors, such as golden eagles, is enhanced by the presence of low cover perennial grasslands; in other areas, foraging suitability is reduced where tall annuals obscure ground visibility. Overall, however, raptor habitat potential is excellent onsite.
The exclusion of livestock grazing also has a positive impact because springs and associated wetlands that are important to many species of wildlife have not been degraded or destroyed by livestock.
Ground Squirrel Poisoning
Ground squirrel poisoning has been conducted annually at LLNL Site 300 on an as-needed basis for almost a decade, using fumarin poison (grain treated with 0.025 percent fumarin). Some 20 acres at existing facilities were poisoned during 1984 and 1985. The use of fumarin has been replaced by sulfur cartridges placed directly into active ground squirrel burrows. Presently, there is no active control program, except for the surface impoundment area where a poisoning regime has been established and will be maintained annually.
Poisons such as fumarin, an anticoagulant, not only can reduce populations of their primary prey but can also poison predators such as foxes, coyote, or raptors. Poisoned bait can also kill other species that feed on it. The San Joaquin pocket mouse, for example, is probably affected much more severely by rodenticides than are the target species.
As long as the use of sulfur cartridges is confined to the high explosive wastewater impoundments, impacts are expected to be insignificant. The high explosive impoundment area is in the southern portion of the site in an area of relatively high human activity, and the impoundments are fenced to prevent access to most species of wildlife. This poison is not used in other areas onsite.
Disking, Grading Fire Roads, and Applying Herbicides to Contain Fires
As mentioned for vegetation, the disking of the 150-ft wide perimeter firebreaks on the northern, and part of the western and eastern boundaries of LLNL Site 300 has taken place since 1980. For several years before that, the same areas were sprayed annually with herbicides. Herbicides also have been applied along paved roads and around some facilities. Approximately 85 miles of fire roads are graded every spring along existing routes.
Some ground-dwelling species could be adversely impacted by disking and grading if they occupy dens in the disturbed areas. The same areas are graded or disked every year, so the impacts would be minimal.
The open space created by dirt roads within the grassland increases the visibility of prey species and hence the suitability of the habitat for many land and air predators. Herbicide applications are currently so minor that only very slight impacts would be expected on herbivorous rodents with small home ranges such as the San Joaquin pocket mouse.
Vehicle Traffic
Vehicles traveling along the paved roads and the better fire trails could cause wildlife mortality. This cause of wildlife mortality, however, would be minimal along the dirt roads and fire trails in the more remote and biologically diverse areas.
The nocturnal seasonal migrations of amphibians such as the tiger salamander and red-legged frogs could result in mortality along roads. But again, impacts should be minimal as nighttime vehicle traffic is sparse and migrations are infrequent.
Fencing of Facilities
The cyclone fencing around the site and around several of the facilities on LLNL Site 300 should not prevent most wildlife from traversing the area, since the fences have many openings through which large mammals can travel. However, fencing around the surface impoundments mentioned below exclude most species of wildlife. On the contrary, fences provide perches for many species of birds, including burrowing owls.
Explosive Testing
At LLNL Site 300, all three primary explosives testing facilities are approximately 1 mile from the site's northern border where explosives testing is conducted almost entirely during the day. The explosions are relatively infrequent (an average of one every 3.5 days in 1990), and wildlife exist near these facilities with minimal impact.
Diurnal raptors that forage directly over the facilities are the species most vulnerable to flying debris and shock overpressure; these include the golden eagle, prairie falcon, northern harrier, black-shouldered kite, ferruginous hawk, and red-tailed hawk. A stunned golden eagle, which may have been injured as the result of explosives testing at Building 801, was discovered in 1985; however, the exact cause of this injury was not determined. This bird recovered and was subsequently released (Orloff, 1986). Warning sounds have been and will continue to be broadcast prior to explosives testing. This serves to discourage raptor use of the area during explosives testing.
High Explosive Process Water Surface Impoundments and Sewage Lagoon
Visual inspection of the high explosive process water surface impoundments revealed few life forms existing within the waters. The impoundments are lined with plastic. A few scattered cattail were observed in one small area; the remainder of this shoreline is devoid of vegetation. Shorebirds have been seen foraging along the edge. Although LLNL Site 300 personnel have reported seeing dead birds in the impoundments on occasion, these deaths cannot be conclusively linked to the impoundments, which have recently passed a water quality control test for fish species (California Assessment Manual-Bioassay-Title 22 screening). Amphibians might use these impoundments, but they are considered suboptimal habitats because they lack submergent and emergent vegetation. Amphibian use of the impoundments probably would be strictly transitory with accompanying minimal impacts. The impenetrable fenced perimeter screens out many species of wildlife.
The highly eutrophic sewage lagoon supports many aquatic species, including a nesting pair of mallards. Wading birds such as the green-backed heron and amphibians such as the red-legged frog have also been observed at this lagoon. Observations in 1991 indicated that a dense stand of bullrush (Scirpus sp.) grows in a small portion of the lagoon.
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