Biodiversity Commons^™

Monitoring Extinction Risk And Threats Of The World's Fishes Based On The Sampled Red List Index, Rafael Miranda, Imanol Miqueleiz, William Darwall, Catherine Sayer, Nicholas K. Dulvy, Kent E. Carpenter, Beth Polidoro, Nadia Dewhurst-Richman, Caroline Pollock, Craig Hilton-Taylor, Robin Freeman, Ben Collen, Monika Böhm

Biological Sciences Faculty Publications

Global biodiversitytargets require us to identify species at risk of extinction and quantify status and trends of biodiversity. The Red List Index (RLI) tracks trends in the conservation status of entire species groups over time by monitoring changes in categories assigned to species. Here, we calculate this index for the world’s fishes in 2010, using a sampled approach to the RLI based on a randomly selected sample of 1,500 species, and also present RLI splits for freshwater and marine systems separately. We further compare specific traits of a worldwide fish list to our sample to assess its representativeness. Overall, 15.1% …

Global Extinction Risk For Seahorses, Pipefishes And Their Near Relatives (Syngnathiformes), Riley A. Pollom, Gina M. Ralph, Caroline M. Pollock, Amanda C.J. Vincent

Biological Sciences Faculty Publications

Few marine taxa have been comprehensively assessed for their conservation status, despite heavy pressures from fishing, habitat degradation and climate change. Here we report on the first global assessment of extinction risk for 300 species of syngnathiform fishes known as of 2017, using the IUCN Red List criteria. This order of bony teleosts is dominated by seahorses, pipefishes and seadragons (family Syngnathidae). It also includes trumpetfishes (Aulostomidae), shrimpfishes (Centriscidae), cornetfishes (Fistulariidae) and ghost pipefishes (Solenostomidae). At least 6% are threatened, but data suggest a mid-point estimate of 7.9% and an upper bound of 38%. Most of the threatened species are …

The Natural History Of The Marsh Rice Rat, Oryzomys Palustris, In Eastern Virginia, Robert K. Rose

Biological Sciences Faculty Publications

The marsh rice rat, Oryzomys palustris, is a common rodent in tidal marshes of eastern Virginia, including those on the barrier islands. It also is present in grassy old fields in upland habitats in the coastal plain and parts of the piedmont of Virginia. This report summarizes what has been learned in recent decades about the population biology of this species in Virginia, including aspects of behavior, density, diet, distribution, genetics, habitats, mammal associates, and reproduction.

Natural History Of The Eastern Harvest Mouse In Southeastern Virginia, Robert K. Rose

Biological Sciences Faculty Publications

The Eastern Harvest Mouse, Reithrodontomys humulis, has been studied extensively in southeastern Virginia since 1979, using a combination of live and pitfall trapping methods. This smallest rodent of eastern North America also is one of most versatile, occupying a range of habitats in southeastern Virginia from old fields in different stages of succession, brushy edges, and forests of different types. As with other species of Reithrodontomys, R. humulis often is associated with the Hispid Cotton Rat, Sigmodon hispidus, with both reaching modest densities in old fields. Two capture-mark-release studies of small mammal communities in southern Chesapeake lasting …

Natural History Of The Southern Bog Lemming In Southeastern Virginia, Robert K. Rose

Biological Sciences Faculty Publications

The isolated subspecies of Southern Bog Lemming of southeastern Virginia, Synaptomys cooperi helaletes, has been studied extensively since its "rediscovery" in the Great Dismal Swamp in 1980. Multiple studies using pitfall traps, starting in the Great Dismal Swamp National Wildlife Refuge and then extending elsewhere in southeastern Virginia and adjacent northeastern North Carolina, have revealed lemmings to be much more widespread and often more common than previously believed, with their presence now confirmed as far west as Surry and Sussex counties, about 30 km east of Petersburg, Virginia. When present, lemmings often are among the most numerous members of …

The Small Mammals Of Southeastern Virginia As Revealed By Pitfall Trapping, Robert K. Rose

Biological Sciences Faculty Publications

Pitfall trapping is a poor method to catch small mammals but the only way to catch and study the Southeastern Shrew (Sorex longirostris), the primary mammal of interest in the field studies reported here. While learning much about its distribution and abundance, still more was learned about the other small mammals present in forests and fields of eastern Virginia. A total of 15 species was captured at 19 locations during the 1990-2013 period, including five shrews, two moles, and eight rodents, representing all but one of the common small mammals in eastern Virginia.

Range Extension For The Dismal Swamp Southern Bog Lemming, Synaptomys Cooperi Helaletes, In Eastern Virginia, Robert K. Rose

Biological Sciences Faculty Publications

The distribution of the Dismal Swamp Southern Bog Lemming is extended to include three counties west of the Dismal Swamp in southeastern Virginia, long considered its only location in the state. Evidence of lemmings was detected at 10 of 27 survey sites, and confirmed by trapping at three of five sites, all dominated by herbaceous vegetation.

Instructions For Building Two Live Traps For Small Mammals, Robert K. Rose

Biological Sciences Faculty Publications

The two live traps described herein, tested in the field over a period of 10 years, are sturdy, long-lasting, and relatively inexpensive to build with readily available materials and simple tools.

Small Mammals In The Great Dismal Swamp Of Virginia And North Carolina, Robert K. Rose, Roger K. Everton, Jean F. Stankavich

Biological Sciences Faculty Publications

Small" mammals were surveyed in a range of habitats in the Great Dismal Swamp of Virginia and North Carolina. The survey is based on three chronologically overlapping studies, each lasting 15-18 months and for which the results have been reported separately. A different trapping method was used in each of the three studies: nest boxes, Fitch live traps, or pitfall traps. Only two species of mammals, both arboreal, were taken in nest boxes, compared with 10 and 9 species in Fitch live traps and pitfall traps, respectively. The Fitch live traps had a much higher catch rate per 1,000 trap-nights …

Reproduction In The Hispid Cotton Rat, Sigmodon-Hispidus Say And Ord (Rodentia: Muridae), In Southeastern Virginia, Robert K. Rose, Michael H. Mitchell

Biological Sciences Faculty Publications

The hispid cotton rat, Sigmodon hispidus Say and Ord, a species of the southwestern United States that has been moving northward and eastward in this century, was first observed in Virginia in 1940. In this study of the cotton rat in southeastern Virginia, most males were reproductively competent from February through November, embryos were recorded from March through October, and litter sizes were comparable to those from other locations except Kansas. Also unlike the cotton rat in Kansas, animals grew at substantial rates during the winter in Virginia. The hispid cotton rat seems to have adjusted its breeding season in …

Comparative Analysis Of The Effects Of Visual And Auditory Stimuli On Avian Mobbing Behavior, C. Ray Chandler, Robert K. Rose

Biological Sciences Faculty Publications

Both visual and auditory stimuli elicit avian mobbing behavior, but there is little comparative information on their isolated and additive effects. Using three combinations of two experimental stimuli (mount and tape of an Eastern Screech-Owl, Otus asio) we tested the effects of stimuli on the frequency, intensity, and duration of avian mobbing behavior. Of 169 mount-only trials, only 11 (6.5%) were successful in attracting birds. Tape-only (n = 169) and mount-and-tape (n = 170) were equally successful in attracting birds (approximately 85% of all trials), but mount-and-tape trials were more likely to initiate mobbing behavior. Birds responding …

Use Of Woody Vegetation By Beavers In Southeastern Virginia, John L. Echternach, Robert K. Rose

Biological Sciences Faculty Publications

Nonbreeding and sometimes transient beavers, Castor canadensis, cut a variety of woody plants throughout the year during a 15-month study at three sites in southeastern Virginia. Ten species of trees were cut in proportions greater than would be expected according to their availabilities. Beavers heavily used viburnum, alder, ironwood, bayberry, tulip poplar, and dogwood. Winter food caches were constructed but were only lightly used.

Distribution And Current Status Of The Threatened Dismal Swamp Southeastern Shrew, Sorex Longirostris Fisheri, Robert K. Rose, Roger K. Everton, Thomas M. Padgett

Biological Sciences Faculty Publications

The Dismal Swamp southeastern shrew, Sorex longirostris fisheri, was given "Threatened" status by the U.S. Fish and Wildlife Service in 1986 because of its limited distribution and the potential threat of interbreeding with the nearby upland subspecies, Sorex l. longirostris. Known from about 20 specimens collected before 1980 and a few dozen taken since then, "fisheri" seems to have morphologically diverged from the smaller upland "longirostris" in association with the development of the Dismal Swamp. The detection of southeastern shrews that are intermediate in size between the two subspecies, coupled with the location of these collection sites on …

The Identification Of The Threatened Southeastern Shrew Using Multivariate Statistical Techniques, Thomas M. Padgett, Roger K. Everton, Robert K. Rose

Biological Sciences Faculty Publications

The threatened subspecies of the southeastern shrew, Sorex longirostris fisheri, is endemic to the Great Dismal Swamp of southeastern Virginia. Previous studies based on discriminant analysis of external measurements determined that intergrades with the upland form, Sorex l. longirostris, exist along the periphery of the Swamp. To better discriminate among these populations, a study of cranial morphology was initiated. Fifteen cranial measurements were taken, using 59 specimens of Sorex collected previously form southeastern Virginia, including the Dismal Swamp. Both Principal Component and Cluster Analyses revealed no significant cranial variation or morphometric patterns within the specimens examined, but a …

Reproductive Strategies Of Meadow Voles, Hispid Cotton Rats, And Eastern Harvest Mice In Virginia, Robert K. Rose

Biological Sciences Faculty Publications

Patterns of reproduction in small mammals in Virginia were examined by autopsying samples of meadow voles (Microtus pennsylvanicus) collected for 23 months near Charlottesville, of hispid cotton rats (Sigmodon hispidus) collected for 14 months in Portsmouth, and by evaluating live-caught eastern harvest mice (Reithrodontomys humulis) trapped for 15 months in Suffolk and for 12 months in Chesapeake. The meadow vole, a microtine rodent with a north temperate and sub-arctic distribution throughout North America, suspended breeding during the winter of peak density but not of declining density. High metabolic rates and other adaptations for winter …

An Evaluation Of Small Rodents In Four Dismal Swamp Plant Communities, F. Elizabeth Breidling, Frank P. Day Jr., Robert K. Rose

Biological Sciences Faculty Publications

Diversity and density of small rodents in the Dismal Swamp are believed to be low. Reasons for this may be excessive predation, heavy interspecific pressure from large rodents, lack of suitable habitat, low food availability or flooding.

Rodent populations were evaluated using live-traps and pitfall traps in four different Dismal Swamp plant communities. Habitat was compared on the basis of phytomass studies previously reported. Flood levels were recorded during live-trapping sessions. Mast from trees was collected in modified mast collectors, and fed to Peromyscus leucopus in the laboratory.

Only two small rodent species were captured: Ochrotomys nuttalli and Peromyscus leucopus …

Small Mammals In Openings In Virginia's Dismal Swamp, Robert K. Rose

Biological Sciences Faculty Publications

In a study of small mammals of openings in the Dismal Swamp of Virginia, seven species were obtained using pitfall traps. Samples included several species rarely caught in the Swamp - seven specimens of the Dismal Swamp subspecies of the southern bog lemming, Synaptomys cooperi helaletes, the first collected in this century; two least shrews, Cryptotis parva; and 15 southeastern shrews, Sorex longirostris fisheri . Results are compared to previous studies, conducted primarily in forested habitats, in which the white-footed mouse, Peromyscus leucopus, and the golden mouse, Ochrotomys nuttalli, were numerically dominant.