Comparison between plant species in bushy-tailed woodrat middens and in the habitat

Bushy-tailed woodrats ( Neotoma cinera ) collect vegetation and store it in middens. We asked to what extent plant species collected by woodrats reflect the array of species growing in the habitat. Species composition of plant clippings at 20 bushy-tailed woodrat middens in central Colorado were compared to vegetation growing within 30 m of the dens. Amount of overlap between midden and habitat species was low (28-49%) when all taxa were included; however, if only woody taxa were considered, overlap was 71-89%. Sorensen's Index of Similarity exhibited a like pattern; the index increased markedly if only woody taxa were included. Only one plant species not found within 30 m of a den occurred in significant amounts of the middens. Bushy-tailed woodrats collected a wide array of species but were more selective the greater the habitat plant diversity. Results of this and other studies indicate the concordance between midden contents and habitat vegetation decreases with increasing habitat plant diversity. Ancient woodrat middens are nonetheless useful to paleontologists seeking to reconstruct past vegetation associations in woody vegetation is well represented in middens.     

The relation between species numbers and island characteristics for habitat islands in a volcanic landscape

Within the Craters of the Moon Lava Flow in southeastern Idaho are kipukas, islands of sagebrush habitat isolated by relatively barren lava. In 1979 I counted the number of species of plants, small mammals, and reptiles for a series of kipukas. The degree of isolation of a kipuka was not related to numbers of species found there; thus, these data do not support the equilibrium theory of island biogeography. For most of the study organisms lava is not a significant barrier to dispersal. Larger kipukas support larger numbers of species. For plants this relationship likely is a result of the increased topographic variety of larger kipukas, whereas for small mammal species minimum area requirements for maintaining populations are met only by larger kipukas. More distant kipukas showed increased density of small mammals possibly as a result of reduced predation. Patterns of distribution in this ecosystem are best explained, not by any all-inclusive community mechanism, but through the agglomerative contributions of a variety of population and community functions.     

Den and relocation site characteristics and home ranges of Peromyscus truei in the White Mountains of California

We used ratio telemetry to describe nighttime movements and daytime den sites of pinyon mice ( Peromyscus truei ) in the White Mountains of California, 1991-1993. Characteristics of nighttime relocations and den sites for mice concurred with previously reported habitat-use information for the species and supported the claim that pinyon mice use multiple daytime sites. However, males and females were associated with different habitat characteristics at den sites, indicating differential microhabitat selection by the sexes, perhaps related to reproductive constraints on females. Pinyon mice also exhibited high variability in den site habitat use in the summer, but low variability in the fall and winter. The dens of male mice were farther apart than those of females, and home range areas averaged 2.9 ha ( s = 4.27 ha) for 8 males , and 0.8 ha ( s = 0.76 ha) for 7 females (overall ￣ x = 1.7 + 2.97 ha). These areas were larger than those reported for other species of Peromyscus . The combined effects of drought and reduced food availability may have contributed to the larger areas used.     

The distribution and habitat preferences of the Afro-European species of Dynamene (Crustacea: Isopoda)

Summary

The geographical distribution of the genus Dynamene is described in the light of the recent discovery of three new species. D. bidentata appears to have a Boreal distribution whilst that of D. edwardsi and D. magnitorata is Atlanto-Mediterranean. D. torelliae, D. bifida, and D. tubicauda have a Mediterranean distribution but the first species may extend into the Black Sea. Only one species, D. ramuscula, has been recorded outside the Afro-European region, in S.E. Australia. The ranges and habitat preferences of those species outside the Mediterranean overlap as do some of those within the Mediterranean, particularly in the Naples Bay region. Juveniles of D. bidentata inhabit and feed on intertidal algae while adults shelter in crevices and empty tests of Balanus perforatus, mainly below MTL. Settlement of males into barnacle tests appears to be random, but females show some degree of aggregation, perhaps to other females. Other species show the same change of habitat at sexual maturity and all inhabit intertidal or inshore localities.     

Notes on mycophagy in four species of mice in the genus Peromyscus

We examined stomach contents of 426 Clethrionomys , 217 C. californicus from western Oregon and 209 C. gapperi from widely scattered areas across North America. Clethrionomys californicus consumed fungi of 28 genera. Clethrionomys gapperi from the Rocky Mountains westward consumed fungi of 23 genera, whereas C. gapperi east of the Rocky Mountains consumed fungi of 7 genera. This study supports the conclusions of an earlier study, limited to Oregon and Washington, that food habits of C. californicus and C. gapperi are more closely related to habitat than to species or subspecies of vole.     

An extant, indigenous tortoise population in Baja California Sur, Mexico, with the description of a new species of Xerobates (Testudines: Testudinidae)

An extant, indigenous desert tortoise population is reported from the cape region of Baja California Sur, Mexico. This population is described and figured as a new species, Xerobates lepidocephalus , distinct from all other North American tortoises including Xerobates agassizii , X. berlandieri , Gopherus flavomarginatus , and G. polyphemus . Xerobates lepidocephalus , or the scaly-headed tortoise, whose range is known only from an extremely small area in the gulf-drainage mountains just south of La Paz, appears to be a peninsular relict whose closest living relative is probably X. agassizii . However, carpal bone affinities connote a close relationship between X. lepidocephalus and the Oligoeene species X. laticunea from Wyoming and Colorado, suggesting that the former species may be one of the more primitive contemporary tortoises of the Xerobates lineage. Such evidence indicates that X. lepidocephalus is not of vicariant origin resulting from the formation of the cape of Baja California. Scaly-headed tortoises likely ranged, and may yet be discovered, in other medium-elevation mountain ranges of the cape.     

Meristic studies of the Gulf of California species of Merluccius,with a description of a new species

Two distinct species of hake are found in the Gulf of California, and in view of the commercial importance of at least one of these, a detailed taxonomical study was carried out. A new species of hake is described from the northern Gulf of California: Merluccius hernandezi. A new population of Merluccius angustimanus was located off the coast of the state of Sinaloa, Mexico. A provisional examination of specimens from this population shows that it differs in important characteristics from the specimens described by Garman (1899) from Panama.

Merluccius hernandezi and M. angustimanus from Sinoloa are immediately separable by the shape of their caudal fin and the lengths of their pectoral fins: in M. hernandezi the caudal fin has a central lobe and in larger specimens it is truncate, while in M. angustimanus it is emarginate; the pectoral fin projects well beyond the anus in M. hernandezi but not in M. angustimanus.

A meristic index was devised which can be used successfully to distinguish between the two species in the field: only 4·13% of specimens studied would have been wrongly identified using this index.     

A new endemic ground beetle species of the genus Tapinopterus Schaum (Pterostichini: Carabidae: Coleoptera) from the Balkan Peninsula,with some notes on its ecology

A new ground beetle species, Tapinopterus (Tapinopterus) macedonicus sp. nov. (from Northern Macedonia, Mount Karad?ica, ?pela Bozguni Cave) is described and diagnosed. Male and female genitalia and other taxonomically important characters are illustrated. A comparison is carried out between the new species and the most closely related taxa. The new species is clearly distinct from its closest congeners and represents an endemic relict inhabiting a limited area in the southern part of the Balkan Peninsula. In addition, its current distribution and some notes on its ecology are also presented.     

Genetic variation of woodrats ( Neotoma cinerea ) and deer mice ( Peromyscus maniculatus ) on montane habitat islands in the Great Basin

Seventeen loci were examined for polymorphism in four populations of Neotoma cinerea and Peromyscus maniculatus on isolated mountain ranges in the Great Basin, one population of each in the Sierra Nevada, and one of each in the Rocky Mountains. All Peromyscus populations had higher levels of heterozygosity than syntopic Neotoma populations.     

Plecoptera and Trichoptera species distribution related to environmental characteristics of the metal-polluted Arkansas River, Colorado

The Upper Arkansas catchment has been polluted with heavy metals from mining for almost 140 yr. Adult Plecoptera and Trichoptera species distributions were recorded from 22 stations along 259 km of main river during 1984-85 so that these could be related to metal deposition and other environmental characteristics. Chemically or physically perturbed sites had poor species richness compared with adjacent sites. There was no sequential downstream increase in species numbers. Filter-feeders proportionally increased downstream as predators declined; these proportions were reset at a high-energy site before the trend resumed. Using canonical correspondence analysis, we found that species composition was most strongly related to changes in distance/altitude and to temperature, particularly after regulatory flows entered the river. The proportion of biological variation explained by river measurements indicated that collected adults were largely derived from the main Arkansas River. Species tolerant of high sedimentary metal concentrations were identified while some other species appeared to be sensitive. The study provides a disturbed-state reference for monitoring effects of remedial actions begun in 1991, and for comparisons with other Colorado rivers.     

Stephonyx californiensis sp. nov. (Amphipoda: Lysianassoidea: Uristidae), a new bathyal scavenger species from the Central Gulf of California,Mexico, and comments on the bathymetric and geographic distribution of the Stephonyx species group

A new species of scavenger amphipod of the genus Stephonyx is described and illustrated. The specimen was caught at 1150 m depth with a modified rectangular lobster trap positioned on the sea bottom in the central Gulf of California, Mexico. The new species is characterised by the absence of eyes; the lateral cephalic lobes medially developed and acute; antennae subequal in length; gnathopod 1 chelate, dactylus simple with three distal stout setae, inner margin sinuous with minute setae; gnathopod 2 subchelate, carpus with ventral margin crenulate, propodus subovate, palm deeply excavate, and dactylus slightly shorter than palm; maxilliped inner plate laceolate, with seven marginal nodular robust setae, distally; telson, each lobe with two dorsal robust setae, distal margin truncated, with one penicillate and two simple setae, in addition to two short spines. Stephonyx californiensis sp. nov. is morphologically similar to S. arabiensis, S talismani, S. laqueus and S. perexcavatus. The new species increases the number of Stephonyx species around the world to 14, with one species inhabiting from the continental shelf to abyssal depths (to 3000 m), 11 species occurring in bathyal depths (201–2000 m), and two other species restricted to abyssal depths (2001–4000 m).

www.zoobank.org/urn:lsid:zoobank.org:pub:346C3B15-E56A-4E17-9C5F-C9FDBB2AED92     

Temporal and spatial patterns of small mammal density and species composition on a radioactive waste disposal area: the role of edge habitat

Small mammal populations inhabiting radioactive waste disposal areas could be important vectors of contaminant redistribution, given sufficiently high numbers. Earlier studies conducted at the Subsurface Disposal Area (SDA) in southeastern Idaho found small mammal densities equaling or exceeding densities in native habitat. Our live-trapping study was conducted in 1988 and 1989 to assess the role of edge habitat (where SDA crested wheatgrass [ Agropyron cristatum ] plantings and native sagebrush habitat are separated by an earthen dike) in facilitating use of this highly modified site by small mammals. Small mammals had a significantly greater density in SDA edge habitat than in the interior. Total density of small mammals and immediately around the SDA appeared to be less variable over time than density in native sagebrush habitat for years when data were available. This phenomenon was largely attributable to steady or increasing SDA population densities of the most common species, Peromyscus maniculatus and Perognathus parvus , during 1988-89, when most small mammal species had below-average densities in surrounding areas. The variety of foraging options in edge habitat may have allowed these relatively opportunistic species to avoid widespread population declines associated with drought years in 1988-89. Movements by P. manicualtus across the boundary were common, suggesting that this species did indeed utilize both habitat types. Preferences for edge habitat could potentially be used to formulate strategies that reduce use of waste site by small mammals.     

Species composition and habitat associations of benthic algal assemblages in headwater streams of the Sierra Nevada, California

Despite their trophic importance and potential importance as bioindicators of stream condition, benthic algae have not been well studied in California. In particular there are few studies from small streams in the Sierra Nevada. The objective of this study was to determine the standing crop of chlorophyll- a and benthic algal species assemblages present in the small 1st- and 2nd-order streams of the Kings River Experimental Watersheds (KREW, watersheds of Bull, Providence, Duff, and Teakettle Creeks) and determine the associations of these measures with stream habitat. We collected samples of benthic algae from rock substrata in September 2002 (7 sites) and 2005 (the same 7 sites plus 5 additional sites). Habitat and water-quality data were collected concurrently. Chlorophyll- a values ranged from 0.2 to 3.2 mg ? m –2 . Chlorophyll- a in the Bull Creek watershed was generally lower than in the other watersheds. Benthic algal assemblages were dominated by diatoms and cyanobacteria. We collected 79 taxa of diatoms in 2002 and 126 taxa in 2005. Diatom taxa richness in individual samples ranged from 15 to 47. Nonmetric multidimensional scaling analysis of arcsine square-root transformed proportional abundances of diatoms identified 3 groups of sites. Bull Creek sites were generally different from other sites (group 1), and the sites from Bull Creek were different in 2002 (group 2) and 2005 (group 3). Five taxa appeared to be particularly important in distinguishing groups: Achnanthidium minutissimum , Cocconeis placentula , Eunotia incise , Eunotia pectinalis var. minor , and Planothidium lanceolatum . Elevation, water temperature, pH, specific conductance, and canopy were habitat variables correlated with the differences in diatom assemblages among sites. Our results provide a valuable baseline for future studies of benthic algae in Sierra Nevada headwater streams and will be particularly important in understanding the effects of different forest restoration management strategies being tested in the KREW project.     

Effects of habitat type and degradation on avian species richness in Great Basin riparian habitats

The overwhelming majority of bird species in the Great Basin region are found in riparian habitats. However, most previous research on the impact of change in habitat condition through degradation on these bird communities failed to account for the large intersite differences, in both habitat type and extent of degradation. We examined songbird communities in 4 riparian habitat types (meadows, willow-birch-, and aspen-dominated forest stands) during summers 1994 (last year of a 7-yr drought) and 1995 (following the 6th wettest winter recorded) in the Toiyabe Mountain Range of central Nevada. Habitat degradation significantly influenced bird species richness in riparian areas, but the impact was dependent upon habitat type. While meadow bird communities were affected adversely by habitat degradation, with significant drops in species richness on degraded sites, bird species richness in forested riparian habitats was consistently greater on degraded sites. Data for the 6 most common species seen during our study indicated that degradation may have influenced distribution of American Robins ( Turdus migratorius ) and Yellow Warblers ( Dendroica petechia ), but habitat type was the best predictor of abundance for House Wrens ( Troglodytes aedon ), Red-naped Sapsuckers ( Sphyrapicus nuchalis ), Warbling Vircos ( Vireo gilvus ), and Brewer's Blackbirds ( Euphagus cyanocephalus ). Avian species diversity in meadow habitats may be linked to moisture levels during specific times of the year. Diversity increased during the pre-migratory period of the dry year (1994) when compared with that of the breeding season, but was unchanged in the wet year (1995).     

Chironomidae (Diptera) species distribution related to environmental characteristics of the metal-polluted Arkasas River, Colorado

Mining in the Upper Arkansas catchment has polluted the river with heavy metals for 140 yr. Pupal and adult chironomid species distribution and sedimentary metal concentrations are provided for 22 stations along 259 km of main river during 1984-85. Complete species identification was achieved only recently. This has produced an unprecedented record of chironomid species distribution for a comparable length of river in the USA. Chemically or physically perturbed sites had poor species richness compared with the next site downstream, suggesting that larvae may drift through unfavorable habitats to benign ones. Using canonical correspondence analysis, we found species composition to be most strongly related to variables expressing the longitudinal axis of the river (distance/altitude, temperature, latitude), while toxicity to zinc was a significant secondary correlate. These river-related environmental variables accounted for a greater proportion of pupal species variation than for adults. This was considered to result from a proportion of adults emerging from habitats beyond the main river. Multivariate analysis identified metal-tolerant and -intolerant species. Generic data revealed the same major trends but indicator taxa were lost. The study provides a disturbed-state reference for monitoring effects of remedial actions begun in 1991, and for comparisons with other Colorado rivers.     

Distribution and ecological characteristics of Lewisia longipetala (Piper) Clay, a high-altitude endemic plant

Lewisia longipetala (Piper) Clay is a high-altitude endemic found in the northern Sierra Nevada. The characteristics of 12 sites with L. longipetala , which represent all known populations, were studied to define habitat requirements of the species. Meso- and microscale characteristics of the habitat were examined, including characteristics of the associated plant community. Average plant size and plant density of L. longipetala were also determined for each population. Similar measurements were made on 6 populations of Lewisia pygmaea (A. Gray) Robinson, a more common Lewisia . Populations of L. longipetala that had larger plants and higher plant density were associated with gently sloped, north-facing sites that were near large, persistent snowbanks and had low vegetative cover. Plant species associated with populations of L. longipetala were similar among the 12 sites and were indicative of mesic, rocky alpine sites. These types of plant communities found near persistent snowbanks are often termed snow-bed vegetation. In contrast, L. pygmaea was found to be less site specific. Lewisia pygmaea was found adjacent to or interspersed with L. longipetala at 5 sites, but was found in areas associated with a higher percentage of herbaceous cover and a wider variety of species. This integration of ecological community information for L. longipetala populations contributes to the interim management and long-term monitoring of this species by providing needed information concerning its habitat and environmental specificity.     

Species composition, emergence, and habitat preferences of Trichoptera of the Sagehen Creek Basin, California, USA

An extensive study of larvae and adult Trichoptera of the Sagehen Creek basin. Sierra Nevada, California, USA, revealed 77 species representing 14 families and 41 genera. Twenty-six species were restricted to small water bodies (spring sources, seeps, spring streams, temporary ponds, and intermittent streams); 27 were restricted to Sagehen Creek, a second-order stream, and the mouths of two large spring streams. Similarity between species caught at black lights and those in emergence traps was 43%. There were two major peaks in adult emergence by species, midsummer and late summer-fall. A few species emerged during winter or throughout most of the year. The species composition of the community showed affinity with Oregon, the Great Basin, and the Rocky Mountains but very little similarity with the California Coast Range. Four of the most abundant species in the basin have very restricted distributions. Ecological separation of several groups of closely related species could be explained by major differences in larval habitats or by different emergence periods.