Michael T. Mengak

Small mammal microhabitat use on young loblolly pine regeneration areas

Abstract Loblolly pine ( Pinus taeda L.) regeneration or establishment impacts a large area over the southern US but few studies have examined the microhabitat relationship of small mammals on young pine stands. We collected over 1600 small mammals on natural and artificial loblolly pine regeneration areas. Twenty-five habitat variables describing cover, forage, and structure were measured or derived at each trap station. We used discriminant function analysis (DFA) to construct microhabitat utilization models for the six most abundant small mammal species common to young loblolly pine regeneration areas including the southern short-tailed shrew ( Blarina carolinensis ), golden mouse ( Ochrotomys nuttalli ), white-footed mouse ( Peromyscus leucopus ), cotton mouse ( P. gossypinus ), harvest mouse ( Reithrodontomys humulis ), and cotton rat ( Sigmodon hispidus ). We compared vegetation characteristics at stations where each species was captured versus stations where it was not captured. Models of species microhabitat associations helped explain observed differences in species succession and abundance. Coarse woody debris (i.e. logs and stumps) was found to be an important microhabitat component for O. nuttalli . Logs and stumps were important to P. gossypinus , P. leucopus and S. hispidus . Shrew capture stations had a significantly taller canopy and significantly greater biomass of vines than did non-shrew captures sites. Golden mouse capture stations had significantly longer logs, shorter distance to nearest log, and lower herbaceous profile diversity. Distance to nearest tree was significantly greater while tree height and vine cover were significantly lower at white-footed mouse capture stations. Cotton mouse microhabitat variables describing woody biomass were greater and stump size, tree height and distance to logs were significantly lower at capture stations. Harvest mice capture stations were characterized as having significantly lower tree height than non-capture stations. Cotton rat microhabitat was characterized by twelve variables but cotton rats were collected almost exclusively on the youngest stands with the greatest grass and herbaceous structure. Numerous variables play an important role in determining habitat quality for the array of small mammal species commonly found in early successional pine habitats in the southeast. Microhabitat models help to explain some of the patterns of species occurrence and succession. While the methods used in this study do not necessarily demonstrate preferred habitat, our results allow identification of areas of use.

Movements of allegheny woodrats in relation to timber harvesting

The Allegheny woodrat (Neotoma magister) occurs in the Appalachian Mountains, forming colonies in rock outcrops, cliffs, and caves. Populations on the northern and western peripheries of the range have experienced drastic declines in the past 20-30 years. Dependence upon rock outcrops makes Allegheny woodrats vulnerable to land-use practices that alter habitats surrounding colonies. To examine the impacts of timber harvesting on Allegheny woodrat behavior, we radiotracked 37 adults during summer 1998 and 1999 in clearcut, diameter-limit, and intact forest stands in the central Appalachians of West Virginia. Home range size and foraging movements generally,were greatest at diameter-limit sites and smallest in intact forests in 1998, following a poor mast crop. We detected no differences among harvest methods in 1999 when mast was abundant. We believe that when hard mast was scarce, woodrats increased foraging movements and home range size to locate mast or sufficient alternative foods. Additionally, woodrats used clearcut and adjacent forested areas in proportion to availability. Our results suggested that clearcutting has minimal impact on woodrat movements, home range, and habitat use if sufficient intact forest is retained adjacent to colonies. Harvesting methods that selectively remove important mast-producing species may represent the greatest disturbance to Allegheny woodrats from forest management.

Allegheny Woodrat (Neotoma magister) Food Habits in the Central Appalachians

Abstract Declining Allegheny woodrat (Neotoma magister) populations suggest a need for more basic ecological information about the species for proper management. Within the core of the Allegheny woodrats distribution in the central Appalachians, food habits and food resource availability are poorly understood. We collected fecal material from known Allegheny woodrats between November 1997 and December 1998 and used microhistological techniques to describe seasonal food habits in the oak (Quercus spp.), dominated forests of the Ridge and Valley and the northern hardwood forests of the Allegheny Plateau physiographic provinces. We examined dietary differences among seasons within and between provinces. Green vegetation, hard mast, soft mast and fungi were present in Allegheny woodrat diets in both provinces in all seasons. Presence of fungi and soft mast in the diet was higher and more widespread seasonally in the Allegheny Plateau than the Ridge and Valley due, in part, to the more mesic forest conditions and more extensive early successional forest habitat in the Allegheny Plateau. Presence of hard mast in the diet tracked acorn production and availability in both provinces in 1997 and 1998. Significant acorn use on the Allegheny Plateau, where oak-dominated forest stands are rare, highlights the importance of hard mast to Allegheny woodrats. Based on food habits we describe, managers seeking to enhance Allegheny woodrat habitat need to provide a mix of habitat conditions containing abundant green vegetation and optimize production and availability of hard mast, soft mast and fungi.

Evaluation of factors restricting distribution of the endangered Key Largo woodrat.

Abstract We examined a suite of models in an information theoretic framework to identify factors restricting presence of the endangered Key Largo woodrat (Neotoma floridana smalli) throughout its remaining habitat. Models containing variables related to availability of nest sites and mammalian predator abundances were supported by our data. Abundance of natural (large overstory trees) and artificial (rock and debris piles) nest substrate were the most important predictor variables, followed by indices of feral cat and raccoon (Procyon lotor) abundance. We recommend increasing abundance of nest substrate in the short term through addition of artificial nest substrate and in the long term through continued protection of remaining forest habitat.

Reproduction, Juvenile Growth and Recapture Rates of Allegheny Woodrats (Neotoma magister) in Virginia

Abstract I studied the natural history of the Allegheny woodrat (Neotoma magister) in Virginia. The species is considered endangered, threatened or of special concern by Natural Heritage Programs in every state in its range. Important details of the woodrats life history, specifically reproduction, growth rate and juvenile survival, are unclear. I trapped 163 juveniles and subadults 416 times over 10,107 trap nights (TN) during an 11-y study. Forty seven percent of juveniles were caught in May and June, whereas 48% of subadults were caught in September or October. Neither juveniles (P < 0.01) nor subadults (P < 0.01) were caught in proportion to trap effort in each month. Based on six litters of 14 juveniles, the average litter size was 2.3 pups. Based on captures and observations, I concluded that woodrat reproduction occurs throughout the year. The average daily weight gain (±se) for a woodrat first caught as a juvenile was 1.26 g/d (±0.23g/d). The average daily weight gain (±se) for a woodrat first caught as subadult was 0.94 g/d (±0.21g/d). Fifty-five percent of all juveniles were never caught after their initial capture. Year to year recapture rate for juveniles was 19%. Twenty-three of 39 (59%) juvenile males were caught only once or on consecutive days in a trap session and never caught again. Sixteen of 31 (48%) juvenile females were caught only once or on consecutive days in a trap session and never caught again.

Influence of Acorn Mast on Allegheny Woodrat Population Trends in Virginia

Abstract Neotoma magister (Allegheny Woodrat) is a medium-sized rodent associated with rock outcrops, talus slopes, caves, cliffs, and boulder fields in the central and southern Appalachians and Allegheny Plateau physiographic provinces. It is currently classified as a G3G4 species and is considered threatened, endangered, or a species of concern in almost every state in which it occurs. As part of a 12-yr study on the status and distribution of the Allegheny Woodrat in Virginia, we collected data on woodrat ecology and population demographics. Herein, we investigate the relationship between acorn production and an index of woodrat abundance for several woodrat populations in Virginia. Woodrat population size was estimated using the Lincoln-Peterson index. Acorn mast surveys were conducted by the Virginia Department of Game and Inland Fisheries from 1989 to 2002 to index mast abundance. Woodrat population estimates were positively correlated (P < 0.05) to the previous years mast crop index at 2 of 4 monitoring sites. Woodrat populations were not correlated to the mast crop two years prior. Acorn production alone does not appear to account for decline in woodrat populations. Range-wide declines in Allegheny Woodrats are likely due to a combination of local and landscape factors, but forest managers should consider acorn production when writing management prescriptions if woodrats are present within the management unit.

ARMADILLO HABITAT SELECTION IN SOUTHWESTERN GEORGIA

Abstract Nine-banded armadillos (Dasypus novemcinctus) have undergone a dramatic range expansion within the last 150 years, yet few quantitative data are available describing their habitat selection patterns, and only a single population has received the vast majority of research attention in general. Because armadillos may negatively impact native fauna, improved knowledge of their habitat selection patterns is needed to better understand their ecology and improve estimates of their future distribution. We used radiotelemetry to monitor 31 armadillos at a site in southwestern Georgia during 2005–2006. Males and females selected habitats similarly. Armadillos were located farther than expected from mature pine habitats within their home ranges, but individual variation in this measure was high, which we suspect may be a fire-dependent response. Armadillos did not prefer hardwood hammocks, as has been reported for other populations, and we suspect this surprising result may have gone undetected had we not used radiotelemetry. Overall, armadillos did not exhibit much evidence of habitat selection at all. It therefore appears that factors other than habitat type, such as temperature and precipitation, may be more important in determining future armadillo distributions and negative impacts may be more widespread than previously thought.

Distribution and Status of Uncommon Mammals in the Southern Appalachian Mountains

Abstract Knowledge of species distribution is fundamental to conservation and management efforts. Unfortunately, distribution of many mammal species in the southeastern United States, including some considered endangered, threatened, or of special concern, has been and remains poorly documented. We queried museums, reviewed the published literature, and searched state Natural Heritage Inventory databases to obtain distributional information for 13 mammal species considered rare (Global Rank G1–G3 or State Rank S1–S3) or of other conservation concern in the Southern Appalachian region. We constructed distribution maps for selected mammal species within the region based on 7 state Natural Heritage Inventory databases and 1539 county records from 26 museums and 57 published sources. Napaeozapus insignis (Woodland Jumping Mouse), Mustela nivalis (Least Weasel), and Tamiasciurus hudsonicus (Red Squirrel) exhibited large (>150 km) geographic differences from currently accepted range maps. Sorex dispar (Rock Shrew), Synaptomys cooperi (Southern Bog Lemming), Neotoma magister (Allegheny Woodrat), and Zapus hudsonius (Meadow Jumping Mouse), exhibited small (<75 km) geographic differences. The remaining 6 species showed little to no range differences from commonly accepted range maps. Because seven of 13 mammals showed substantial differences from known range maps, our updated maps may aide managers and others in focusing surveying and conservation efforts.

Technique, Safety, and Efficacy of Intra- Abdominal Transmitters in Nine-Banded Armadillos

Abstract The future management of nine-banded armadillos (Dasypus novemcinctus) requires solid space-use and activity data, which are currently lacking and which radiotelemetry can provide. External radiotransmitters have not been successful applied with this species. To make recommendations for intra-abdominal radiotransmitter placement in nine-banded armadillos, we 1) evaluated 4 different anesthetic protocols for safety, efficiency, and cost-effectiveness; 2) evaluated a surgical technique for the intra-abdominal placement of radiotransmitters that addresses problems described in previous studies; and 3) evaluated the physiologic and behavioral effects of such a technique. We captured and surgically implanted 37 nine-banded armadillos using either butorphanol and isoflurane, ketamine alone, ketamine and xylazine, or a combination of butorphanol, ketamine, and medetomidine for anesthesia. We recovered and necropsied armadillos after the completion of the study. The objective and subjective assessment of butorphanol, ketamine, and medetomidine combination protocol, followed by reversal of the anesthesia with atipamezole, showed that it was the best overall anesthetic protocol for field use, providing both a smooth induction and fast recovery. We evaluated the fate and effects of radiotransmitters on 13 recovered animals at the end of the study and found no adverse effects. We recommend the implantation of radiotransmitters that are allowed to free-float within the abdominal cavity and specifically emphasize the need for strict aseptic technique. Wildlife managers and wildlife veterinarians aiming to implant nine-banded armadillos with radiotransmitters will benefit from using the recommended anesthetic protocol and surgical technique in future studies.

Fleas (Siphonaptera) of the Allegheny Woodrat (Neotoma magister) in West Virginia with Comments on Host Specificity

Abstract Previous research has indicated fewer host-specific ectoparasites on woodrats of the eastern United States as compared to western woodrat species. The Allegheny woodrat (Neotoma magister) is a species of conservation concern that is associated with rocky habitats in the Appalachian and Interior Highland regions in the eastern United States. We examined Allegheny woodrat flea parasites in the core of the distribution to further elucidate patterns of ectoparasite host specificity in woodrats of the eastern United States. Of 346 fleas collected from 62 Allegheny woodrats, all but 1 were identified as Orchopeas pennsylvanicus. The single exception was a male Epitedia cavernicola, which represents only the second collection of this species from West Virginia. Unlike the eastern woodrat (Neotoma floridana), which hosts a variety of generalist flea parasites, Allegheny woodrats in our study were host to only 2 flea species, both of which are host specific to woodrats. We suggest that flea host specificity may be related to the specific habitat requirements of this species.