Glennis A. Kaufman

Influence of Fire and Topography on Habitat Selection by Peromyscus maniculatus and Reithrodontomys megalotis in Ungrazed Tallgrass Prairie

Twelve species of small mammals were captured in 10 treatment areas manipulated by fire on the Konza Prairie Research Natural Area, Kansas. The four fire classes studied were annual fire, first year after fire with previous fire ≥4 years earlier (year 1), 2–4 years since fire (years 2–4), and ≥5 years since fire (year 5+). Of the two common rodents, Peromyscus maniculatus selected year 1 sites in all seasons, whereas Reithrodontomys megalotis selected annual fire sites in spring and years 2–4 sites in summer with no differences in autumn. Based on 12 fire-topography categories (fire categories the same as above; topography categories: upland, breaks [area of the limestone outcrop at the edge of the hills], and lowland), habitat selection by P. maniculatus and R. megalotis differed significantly between autumn and summer, but could not be tested for spring. Analysis of structural features demonstrated that habitat use by P. maniculatus was related negatively to amount of litter and positively to amount of exposed soil and grass. These three features were related to time since fire; however, the lack of litter likely was the most important feature in the positive response by P. maniculatus to conditions following a fire. In contrast, no significant relationships were found between habitat features and use by R. megalotis .

Effect of Microhabitat Features on Habitat Use by Peromyscus leucopus

Habitat use and selection by the white-footed mouse (Peromyscus leucopus) were examined in riparian woods and associated grassy, shrubby and limestone outcrop habitats on the Konza Prairie Research Natural Area near Manhattan, Kansas. Analysis of captures on a large, irregular grid (843 stations) demonstrated significant differential use of habitat types by P. leucopus. Selection of habitat types was related to the vertical structure of the vegetation with areas of complex vertical structure (trees with large shrubs, large shrubs without trees or trees with small shrubs) selected over those with less well-developed vertical structure (trees without shrubs, small shrubs without trees or grass). The same basic pattern persisted when microhabitat features in the immediate area of traps were examined. Use of microhabitats associated with rocks, logs, stumps and fallen trees in the riparian woods revealed greater use of areas with dense cover. The use of microhabitats associated with limestone outcrops confirmed a pattern of greater use of protected than of open areas. Patterns of habitat and microhabitat use were generally consistent with the use of habitat features to avoid predators; however, food distribution was not examined and availability of food in different sites may explain part of the use patterns. Limited observations on habitat selection by Neotomafioridana suggested that competitive interactions between P. leucopus and N. floridana were relatively unimportant in the macroand microhabitat use patterns of P. leucopus.

Reproduction by Peromyscus polionotus: number, size, and survival of offspring

Relationships involving female size, litter size, offspring size, and offspring survival were examined using records available from a laboratory colony of Peromyscus polionotus. Female size was positively correlated to (1) birth size of offspring, (2) number of offspring per litter, (3) litter mass at birth, (4) size of offspring on day 21, and (5) postnatal gain from day of birth to day 21. In contrast to female size, increased litter size led to (1) reduced birth size, (2) reduced size on day 21, (3) reduced postnatal gain, and (4) reduced survival of offspring. On day 21, mice in litters experimentally reduced to three from four or more individuals were larger, gained more, and were more likely to have survived than offspring in unmanipulated litters, but were similar in the three characteristics to mice in natural litters of three. Results of litter reductions indicate that female P. polionotus do not simply prorate “potential” parental investment into a smaller number of offspring, but rather the interaction between a female and the number of nursing young leads to changes in both investment per progeny and total investment per litter.

Influence of Woody Vegetation on Small Mammals in Tallgrass Prairie

ABSTRACT We examined response of small mammals to woody invasion of tallgrass prairie in northeastern Kansas by sampling sites that ranged from 0 to 100% in woody cover (i.e., frequently burned prairie to unburned closed-canopy gallery forest; woody coverage mapped from satellite imagery). Abundance and biomass of small mammals initially increased with increasing woody vegetation, but then decreased to their lowest level at 100% woody cover. Richness was greatest (an average of seven species) where woody cover was ≤17% and decreased to one species where woody cover was 100%. Abundance of white-footed mice (Peromyscus leucopus) increased as woody cover increased from 0 to 62% cover, but decreased in forested sites (100% cover). Abundance of western harvest mice (Reithrodontomys megalotis) decreased as woody cover increased; they were not recorded in forested sites. Deer mice (P. maniculatus) were present in sites with no to low levels of woody vegetation, but were absent in sites with moderate to high levels of woody cover. The 11 species captured were recorded in sites that had little woody vegetation (≤17% cover), whereas only seven species were captured at sites where considerable woody vegetation (≥28% cover) occurred. Even white-footed mice and eastern woodrats, which are considered woodland forms, decreased in abundance or were absent from forested sites. Overall, the results demonstrate that even relatively small amounts of woody vegetation in prairie landscapes can alter abundance, biomass and species richness and composition of small mammal communities.

Influence of Grazing by Bison and Cattle on Deer Mice in Burned Tallgrass Prairie

Abstract We studied the influence of grazing by bison (Bos bison) and by cattle (B. taurus) on deer mice (Peromyscus maniculatus) in tallgrass prairie at the Konza Prairie Biological Station in 1997 and 1998. Small mammals were sampled by one 10-station trapline in each of four bison-grazed enclosures, four cattle-grazed enclosures and four ungrazed sites. Enclosures were 4.9 ha and the biomass of grazers in each was similar. All sites were burned annually. We sampled small mammals for 4 consecutive nights in spring before fire, in spring after fire and in autumn. Deer mice were the most abundant species (n = 285; 83% of all small mammals) captured in all treatments and in each trapping period. Deer mice were significantly more abundant in bison-grazed and cattle-grazed sites than in ungrazed sites in spring before fire (P < 0.01 and P < 0.05, respectively), but were similar in abundance in grazed and ungrazed sites following fire. Abundance of deer mice was significantly higher in bison-grazed sites than in cattle-grazed and ungrazed sites in autumn (P < 0.05 and P < 0.001, respectively). Bison and cattle differ in grazing and nongrazing behaviors (e.g., wallowing by bison) that result in differences in vegetation structure. It is likely that differences in deer mouse abundance between bison-grazed and cattle-grazed treatments were due to differences in vegetation structure caused by the two types of grazers.

Ecology of Small Mammals in Prairie Landscapes

When one crosses the prairie landscapes of central North America, one becomes aware of the impacts that humans have had on the region. Recent anthropogenic modifications of the presettlement prairie not only have changed vegetation but also altered distributional ranges, spatial use within ranges, and total numbers of many species of animals. Although human activities often reduce ranges and abundances of animals and these reductions usually are the foci of issues of conservation, human impacts do not always lead to such reductions. Anthropogenic changes can and do lead to increases in numbers, distributional ranges, or both for some species. Some of these increases result from altered landscapes that provide conditions more suitable for some species than the conditions available in native environments. Other increases are due to intentional introductions of both domestic and wild species and to accidental introductions of wild species.

SPECIES RICHNESS-PRODUCTIVITY RELATIONSHIP FOR SMALL MAMMALS ALONG A DESERT-GRASSLAND CONTINUUM: DIFFERENTIAL RESPONSES OF FUNCTIONAL GROUPS

Abstract We used published data to calculate small-mammal species richness at 43 sites in North America to examine the response of species richness to increasing primary productivity. We estimated species richness for the entire community and for each of 4 functional groups (insectivore, granivore, herbivore, and omnivore). Total richness exhibited a significant unimodal relationship to increasing amounts of annual precipitation and was driven by granivores; this functional group exhibited the most pronounced decline in richness with high precipitation. We suggest that the decline in granivore richness is due to increased litter associated with increased productivity.

LONG-DISTANCE MOVEMENTS OF THE DEER MOUSE IN TALLGRASS PRAIRIE

Long-distance movements may play an important role in regulating populations of small mammals. To examine such movements, we livetrapped 1,712 deer mice (Peromyscus maniculatus) on 14–28 permanent traplines from autumn 1981 to spring 1990 on the Konza Prairie Biological Station, Kansas. These data were collected under a variety of climatic and biotic conditions that resulted in detection of .100 long-distance movements by deer mice between traplines (moves of 50–1,320 m). Males made more moves than females, but distance moved did not differ by sex. Age did not affect the number or distance of movements. On average, more long-distance moves occurred in spring and summer than in autumn, but distance did not differ by season. Proportion of the population making intertrapline movements was inversely related to abundance of deer mice. Deer mice did not exhibit a fire-positive response in long-distance movement. Our results indicate that deer mice may be more mobile than originally thought. Researchers should incorporate improved methods for detecting longer movements to better understand causes and consequences of these movements.

Changes in Body Mass Related to Capture in the Prairie Deer Mouse (Peromyscus maniculatus)

We examined the effect of a single live-trap capture on body mass of deer mice ( Peromyscus maniculatus ) by comparing body mass of individuals observed in artificial burrows (no capture stress) with body mass recorded <24 h later following a single capture in a live trap. Nearly 90% of our 374 observations showed changes in body mass, and 90% of these 336 changes were losses in body mass. Changes in body mass were affected by age, gender, season of capture, and reproductive condition of adult females. Abiotic factors also affected changes in body mass of mice in traps. Subsequent observations of individuals in burrows suggested that body mass changes due to trap confinement were short-term impacts, as differences found in body mass between consecutive observations of adult deer mice in artificial burrows did not differ significantly from zero. However, numerical differences in mass between burrow observations were directly related to initial mass lost in live traps.

LONG-TERM VARIATION IN ABUNDANCE OF ELLIOT'S SHORT- TAILED SHREW (BLARINA HYLOPHAGA) IN TALLGRASS PRAIRIE

Abstract Elliots short-tailed shrews (Blarina hylophaga) were studied in tallgrass prairie at Konza Prairie Biological Station, Kansas. Based on sampling of 14 permanent traplines from autumn 1981 to spring 1999, relative abundance was high in autumn (X̄ = 2.5 ± 0.4 SE shrews/trapline) but very low in spring (<0.1 shrews/trapline). Interannual variability in abundance in autumn was large with a range 0.1–7.0 shrews/trapline. Relative abundance of shrews in autumn was correlated positively with precipitation, soil moisture, and depth of plant litter and correlated negatively with proportion of area burned and maximum temperature. Two variables, precipitation, and amount of litter, accounted for 87% of variation in abundance of shrews in autumn. Ambient moisture and a well-developed litter layer that ameliorates microclimatic extremes appear to be the most important factors influencing abundance of shrews in tallgrass prairie.