SignificanceHow climate change and biological invasions interact to affect biodiversity is of major concern to conservation. Quantitative evidence for the nature of climate change–invasion interactions is, however, limited. For the soil ecosystem fauna, such evidence is nonexistent. Yet across the globe, soil-dwelling animals regulate belowground functioning and have pronounced influences on aboveground dynamics. Using springtails as an exemplar taxon, widely known to have species-specific effects on below- and aboveground dynamics, we show that across a wide latitudinal span (16–54°S), alien species have greater ability to tolerate climate change-associated warming than do their indigenous counterparts. The consequences of such consistent differences are profound given globally significant invasions of soil systems by springtails.

Minimum counts are commonly used to estimate population size and trend for wildlife conservation and management; however, the scope of inference based on such data is limited by untestable assumptions regarding the detection process. Alternative approaches, such as distance sampling, occupancy surveys, and repeated counts, can be employed to produce detection‐corrected estimates of population parameters. Unfortunately, these approaches can be more complicated and costly to implement, potentially limiting their use. We explored a conceptual framework linking datasets collected at different spatial scales under different survey designs, with the goal of improving inference. Specifically, we link landscape‐scale distance sampling surveys with local‐scale minimum counts in an integrated modeling framework to estimate mountain goat (Oreamnos americanus) abundance at both the local and regional scale in south‐central Alaska, USA, and provide an estimate of detection probability (i.e., sightability) for the minimum counts. Estimated sightability for the minimum count surveys was 0.67 (95% credible interval [CrI] = 0.52–0.83) and abundance for the entire area was 5,600 goats (CV = 9%), both in broad agreement with estimates from previous studies. Abundance estimates at the local scale (i.e., individual min. count unit) were reasonably precise (trueCV̅ = 18%), suggesting the integrated approach can increase the amount of information produced at both spatial scales by linking minimum count approaches with more rigorous survey designs. We propose that our integrated approach may be implemented in the context of a modified split‐panel monitoring design by altering survey protocols to include frequent minimum counts within local count units and intermittent but more rigorous survey designs with inference to the entire study area or population of interest. Doing so would provide estimates of abundance with appropriate measures of uncertainty at multiple spatial scales, thereby improving inference for population monitoring and management. © 2019 The Wildlife Society.

We compared the reproductive biology, dispersal, and subadult survival of bald eagles (Haliaeetus leucocephalus) from nest sites in suburban and rural landscapes in west‐central Florida, USA, from 1997 to 2001. We documented the reproductive outcome of randomly selected suburban (n = 60) and rural (n = 60) bald eagle nest attempts. We also used satellite tracking packages on randomly selected rural (n = 35) and suburban (n = 35) bald eagle fledglings. Nest‐site occupancy varied among years (range = 75.0–100.0%), but averaged 90% for nests in both land‐use categories. The overall mean nesting start date was similar for both groups (suburban = 11 Dec, rural = 13 Dec). Bald eagles occupying nest sites in both land‐use categories raised an average of 1.3 young to 8 weeks‐of‐age, and pairs that fledged ≥1 young raised an average of 1.7 young to 8 weeks‐of‐age. Most bald eagle fledglings from our study area migrated northward, some as far as Newfoundland, Canada. The core summering area was the Chesapeake Bay and the coastal plain of North Carolina, USA. Successful fledglings started northward migration earlier on average at rural than at suburban nest sites (124 vs. 132 days‐of‐age). Survival of both groups was similar until dispersal (approx 91%); however, during the first northward migration, mortality of suburban fledglings increased disproportionately. One year after fledging, survival of rural fledglings was 89% compared to 65–72% for suburban fledglings. Survival of the 2 groups was similar (84–90%) thereafter. Suburban bald eagles died more often from anthropogenic factors (primarily electrocution and vehicle collision) than rural bald eagles, though most of these deaths occurred in rural areas after dispersal from natal areas. We suggest that suburban bald eagle fledglings were more acclimated to dangerous anthropogenic landscape features than rural eagles, and as such did not regard them with the same degree of caution. Despite the difference in first‐year mortality, population models suggest that both groups are experiencing positive population growth rates.

As global climates change, alien species are anticipated to have a growing advantage relative to their indigenous counterparts, mediated through consistent trait differences between the groups. These insights have largely been developed based on interspecific comparisons using multiple species examined from different locations. Whether such consistent physiological trait differences are present within assemblages is not well understood, especially for animals. Yet, it is at the assemblage level that interactions play out. Here, we examine whether physiological trait differences observed at the interspecific level are also applicable to assemblages. We focus on the Collembola, an important component of the soil fauna characterized by invasions globally, and five traits related to fitness: critical thermal maximum, minimum and range, desiccation resistance and egg development rate. We test the predictions that the alien component of a local assemblage has greater basal physiological tolerances or higher rates, and more pronounced phenotypic plasticity than the indigenous component. Basal critical thermal maximum, thermal tolerance range, desiccation resistance, optimum temperature for egg development, the rate of development at that optimum and the upper temperature limiting egg hatching success are all significantly higher, on average, for the alien than the indigenous components of the assemblage. Outcomes for critical thermal minimum are variable. No significant differences in phenotypic plasticity exist between the alien and indigenous components of the assemblage. These results are consistent with previous interspecific studies investigating basal thermal tolerance limits and development rates and their phenotypic plasticity, in arthropods, but are inconsistent with results from previous work on desiccation resistance. Thus, for the Collembola, the anticipated advantage of alien over indigenous species under warming and drying is likely to be manifest in local assemblages, globally.

We studied adult Cooper's hawks Accipiter cooperii on two study areas in north Florida from 1995 to 2001, an area dominated by large plantations managed for northern bobwhite Colinus virginianus and an area of mixed farmland and woods with no direct bobwhite management. We monitored 76 Cooper's hawk nesting attempts at 31 discrete nest areas, and radio-tagged 19 breeding males and 30 breeding females that we radio-tracked for up to 5 y. Nesting density (565 to 1,494 ha per occupied nest area) was comparable but productivity (1.8 and 2.8 young fledged per occupied and successful nest area, respectively) was lower than for the species elsewhere. Prey may have been more limiting than in other areas studied because chipmunks Tamias striatus, an important prey elsewhere, were absent. Annual Cooper's hawk survival averaged 84% for males and 81% for females, except in 1998 when survival was substantially lower. Average annual home-range size for male Cooper's hawks was 15.3 km2 inclusive of one nesting area. Female annual ranges averaged 30.3 km2, and included from three to nine nesting areas. Daily space use was similar between the sexes, but females had separate breeding and nonbreeding ranges whereas males were sedentary. Females used the same nonbreeding areas among years, but switched nesting areas 68% of the time compared with only 17% for males. Birds comprised 88% of the breeding and 98% of the nonbreeding season diet of Cooper's hawks by frequency. Important prey species all year were mourning doves Zenaida macroura, blue jays Cyanocitta cristata, and northern bobwhite; during summer, cattle egrets Bubulcus ibis, northern mockingbirds Mimus polyglottos and northern cardinals Cardinalis cardinalis were also important; and during autumn and winter, killdeer Charadrius vociferus, yellow-billed cuckoos Coccyzus americanus, and chickens were important. Female Cooper's hawks took larger prey than males; females were responsible for most cattle egret and chicken kills; whereas, males took most blue jays, killdeer, northern mockingbirds, and northern cardinals. Of avian prey brought to nests, 64% were nestling birds. Most adult male Cooper's hawks were adept at raiding bird nest boxes. Male Cooper's hawks captured 85% of the prey fed to nestlings. Female Cooper's hawks relied on males for food from early March until young were ≥12 d old, and 6 of 10 breeding females monitored intensively were never observed foraging for their broods. Most prey brought to nestling Cooper's hawks was captured within 2 km of nests, and foraging effort was consistent throughout the day. During the nonbreeding season, most prey captures occurred before 0900 hours or at dusk. Northern bobwhite made up 2% of male and 6% of female Cooper's hawk prey annually by frequency; this extrapolated to 18 bobwhite/year/adult Cooper's hawk on both study areas, 59% of which were captured between November and February. Outside the breeding season, male Cooper's hawks foraged evenly over their home range whereas females tended to focus on prey concentrations. Because female Cooper's hawks were so adept at finding and exploiting prey hotspots, perhaps the best strategy for reducing predation on bobwhite is habitat management that produces an even distribution of bobwhite across the landscape.

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We studied the nesting ecology of the Chimango Caracara ( Milvago chimango), a common yet poorly known raptor on Chiloe Island, southern Chile, during two breeding seasons. Deforestation and land clearing in this landscape may be benefiting this raptor, which is tolerant of open and disturbed habitats and human activity. Chimangos nested at different heights in a variety of trees and shrubs, but nests were always well concealed because they were placed centrally and in dense vegetation within the substrate. Egg laying occurred in most nests in October during both years; the most common clutch sizes were 2 or 3 eggs. The incubation and nestling periods were approximately 5(2 nests) and 6(1 nest) weeks, respectively. Nest success (Mayfield) for 72 nests averaged 57% for the two years. Productivity averaged 1.22 ± 0. 1 1 fledglings per active nest and did not differ between years. For nests located during both years ( n = 15), productivity was slightly higher in 1997-1998 and more nests failed in 1998-1999. Two pairs attempted to renest after nest failure but were not successful. Habitat and landscape features associated with high productivity of chimango nests included exotic trees and shrubs, tidal flats, linear forest strips, and occupied houses or barns. Successful nesting was associated with exotic trees and shrubs. Nesting density was highest along beaches, although not all pairs that built nests along beaches laid eggs. Successful nests along beaches fledged twice as many young as inland nests. Continued clearing of the rainforest in this region may provide increased foraging opportunities for this raptor but may also result in fewer nest sites.

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