Donald W. 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 Illumination and Surface Structure on Space Use by Prairie Deer Mice (Peromyscus maniculatus bairdii)

Effects of illumination and habitat structure on activity of prairie deer mice ( Peromyscus maniculatus bairdii ) were assessed by use of sand tracking in experimental arenas. Activity was significantly lower on bright (median = 1,036 footprints in sand transects) than dark nights (2,608 footprints). Use of space along arena walls (16.7% of arena area) was significantly greater than that in an equal area in the middle of the arena on both bright (walls, 37.3% of footprints; middle, 7.9%) and dark nights (23.2%; 14.0%). Use of the side of the arena with simulated habitat structure that cast shadows (33.3% of arena area) was significantly greater than that in an equal area on the side without added structure on bright (structure, 50.0% of footprints; no added structure, 33.9%), but not dark nights (38.3%; 34.9%). Seed use on bright and dark nights did not reflect patterns of activity demonstrated by footprints.

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.

Temporal and Spatial Variability as Neglected Ecosystem Properties: Lessons Learned From 12 North American Ecosystems

Evaluating and monitoring the “health” of large-scale systems will require new and innovative approaches. One such approach is to look for ecological signals in the structure of ecological variability observed in space and time. Such variability is sometimes considered something to minimize by clever sampling design, but may in itself contain interesting ecological information (Kratz et al. 1991). In fact, much of ecology can be considered an attempt to understand the patterns of spatial and temporal variability that occur in nature and the processes that lead to these patterns. Despite widespread interest in patterns of variation there have been relatively few attempts to describe comprehensively the temporal and spatial variation exhibited by ecological parameters. As a result, we have no general laws that allow us to predict die relative magnitude of temporal and spatial variability of different types of parameters across the full diversity of ecological systems. Even within single ecosystems, understanding of the interplay between temporal and spatial variability is lacking. For example, Lewis (1978) noted that despite a large literature, the relation between temporal and spatial variability in plankton distribution within a lake is not well understood. Matthews (1990) makes a similar point regarding fish communities in streams.

Effects of Plant Litter on Foraging and Nesting Behavior of Prairie Rodents

Interspecific differences in seed use and location of nest sites of Peromyscus leucopus, P. maniculatus, Reithrodontomys megalotis , and Microtus ochrogaster were found among experimental patches of habitat that differed only in amount of plant litter. P. leucopus and P. maniculatus foraged selectively in patches with sparse litter and used nest boxes in these patches more than expected. R. megalotis and M. ochrogaster foraged selectively and nested in patches with moderate litter; both nested more in litter than in nest boxes. All species consumed more seeds in patches with moderate litter on bright than dark nights. P. leucopus consumed fewer seeds and P. maniculatus tended to reduce consumption from dark to bright nights; however, R. megalotis and M. ochrogaster consumed similar amounts of seeds under both light conditions. P. leucopus and P. maniculatus forage in open habitats and may perceive changes in light intensity more readily than either R. megalotis or M. ochrogaster that forage in structurally complex habitats. Interspecific differences in activity between dark and bright nights may be related to the ability of each species to detect changes in risk of predation related to variation in light intensity.

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.