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Invasion and expansion of non-native and native plants have altered vegetation structure in many terrestrial ecosystems. Small mammals influence multiple ecosystem processes through their roles as ecosystem engineers, predators, and prey, and changes to vegetation structure can affect habitat use, community composition, and predator-prey interactions for this assemblage of wildlife. In the sagebrush (Artemisia spp.) shrublands of the western United States, invasion by nonnative grasses and expansion of native conifer trees beyond their historical range has altered vegetation structure. These changes may potentially affect distributions and interactions of deer mice (Peromyscus maniculatus), which are generalist omnivores, and Columbia Plateau pocket mice (Perognathus parvus), more specialized granivores. To assess the extent to which altered habitat affects small-mammal density, survival, and home-range size, we examined these aspects of smallmammal ecology along a gradient of cheatgrass (Bromus tectorum) invasion and western juniper (Juniperus occidentalis) establishment in sagebrush shrublands in southwestern Idaho, USA. From 2017-2019, we used a spatially explicit markrecapture design to examine attributes of small-mammal ecology along an invasion gradient. We did not find support for an effect of cheatgrass cover on density or survival of either species. Home-range size of deer mice was 2.3 times smaller in heavier cheatgrass cover (60%) compared to areas with little or no cheatgrass cover. Density of deer mice was highest (5 individuals/ha) in areas with 10% juniper cover and decreased with increasing juniper cover, whereas density of pocket mice was positively influenced by shrub cover. Survival of deer mice declined as juniper stem density increased. Conversely, survival of pocket mice increased with increasing juniper stem density. We found evidence for interspecific interactions between these 2 species, in the form of a densitydependent effect of deer mice on pocket mouse home-range size. Home-range size for pocket mice was 2 times smaller in areas with the highest estimated density of deer mice compared to areas with low densities of deer mice. Our data provides unique information about how small mammals in the sagebrush steppe are affected by expanding and invasive plant species and potential ways that habitat restoration efforts, in the form of conifer removal, may influence small mammals. Understanding the response of small mammals to conifer expansion or removal may shed light on the demographic and numerical responses of other wildlife associated with the sagebrush biome, including predators. [ABSTRACT FROM AUTHOR]

We examined age-related reproductive success and the short-term consequences of dispersal by known-aged Cliff Swallows (Petrochelidon pyrrhonota) breeding in Texas from 1975-86. Clutch size increased with age in females, and males and females [greater than or equal to]2 yrs old fledged more young than yearlings. Sixteen percent (76/463) of birds dispersed between breeding seasons and we observed female-biased dispersal. Birds that dispersed to a different colony at age 2 produced 0.91 fewer fledglings post-dispersal compared to the previous year. and birds that dispersed at age 3 produced 0.34 more fledglings post-dispersal compared to the previous year; females experienced greater benefits than males when they dispersed at age 3 yrs. Younger dispersers incur short-term costs which might have important consequences for lifetime reproductive success for a short-lived passerine. However, potential population-level consequences from dispersal costs is likely minimal given the low rate of dispersal we observed. Keywords: age-dependent. Cliff Swallow, colonial, dispersal, Petrochelidon pyrrhonala. reproductive success, Dispersal is widely acknowledged as an important aspect of avian life history due to its effects on population dynamics, gene flow, and the distribution of species (Johnson & Gaines 1990). [...]

This article focuses on Kansas Army Ammunition Plant (KSAAP) in southeast Kansas. It was historically dominated by native bluestem grasses and deciduous forest, but now consists of agricultural crops and pastures planted with tall fescue (Lolium arundinaceum), an exotic cool season grass. The fescue-dominated pastures, which are maintained by annual fertilization, provide poor habitat for wildlife compared to native tallgrass prairie. Cattle preferentially choose the tender, actively growing fescue shoots for grazing, which should decrease tall fescue biomass over time through repeated defoliation and removal of reproductive structures.