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Roost locations can be an important contributor to vulture conflicts with humans, but factors influencing roost-site selection at a landscape level remain largely unexplored. Further, there has been little research comparing how these factors vary between nocturnal and diurnal roosting sites. We used remote cameras to document daily variation in vulture use of 21 roosts (20 communication/water towers and 1 natural roost) near Beaufort, South Carolina, USA from October 2019–August 2020. Numbers of vultures on roosts increased with decreasing urban cover and with greater distance to water, but were not influenced by habitat fragmentation or elevation. Roosts surrounded by greater proportions of urban cover were used more often during the day, whereas roosts adjacent to less urban cover were more commonly used at night. We suggest that this relationship results from a greater daytime association with human development, areas that likely provide food and favorable soaring conditions for vultures. Vultures tended to depart nocturnal roosts before sunrise and return within two hours of sunset, indicating that aircraft collision risk resulting from movement around nocturnal roosts would be elevated during these times. Several communication towers routinely had > 100 vultures roosting on them at once, likely contributing to conflict with humans. Our findings reiterate the generalism of these species and their capacity to exploit novel structures for roosting, which has likely contributed to range expansions and resultant increases in human-vulture conflicts over the past several decades.

Where two sympatric species compete for the same resource and one species is dominant, there is potential for the subordinate species to be affected through interference competition or energetic costs of avoiding predation. Fishers (Pekania pennanti) and American martens (Martes americana) often have high niche overlap, but fishers are considered dominant and potentially limiting to martens. We observed presence and vigilance of fishers and martens at winter carcass sites using remote cameras in Michigan, USA, to test the hypothesis that interference competition from fishers creates a landscape of fear for martens. Within winters, fishers co-occupied 78–88% of sites occupied by martens, and martens co-occupied 79–88% of sites occupied by fishers. Fishers displaced martens from carcasses during 21 of 6117 marten visits, while martens displaced fishers during 0 of 1359 fisher visits. Martens did not alter diel activity in response to fisher use of sites. Martens allocated 37% of time to vigilance compared to 23% for fishers, and martens increased vigilance up to 8% at sites previously visited by fishers. Fishers increased vigilance by up to 8% at sites previously visited by martens. Our results indicate that fishers were dominant over martens, and martens had greater baseline perception of risk than fishers. However, fishers appeared to be also affected as the dominant competitor by putting effort into scanning for martens. Both species appeared widespread and common in our study area, but there was no evidence that fishers spatially or temporally excluded martens from scavenging at carcasses other than occasional short-term displacement when a fisher was present. Instead, martens appeared to mitigate risk from fishers by using vigilance and short-term avoidance. Multiple short-term anti-predator behaviors within a landscape of fear may facilitate coexistence among carnivore species.

Environmental changes since the Pleistocene and commercial whaling in the last few centuries have drastically reduced many whale populations, including gray whales in the North Pacific. Herein we use complete mitogenome sequences from 74 individuals to evaluate gray whale phylogeography and historical demography, then use environmental niche modeling to assess how habitat availability has changed through time for Pacific gray whales. We identify a large degree of haplotype sharing between gray whales sampled in Russian and Mexican waters, coupled with very limited matrilineal population structure. Confirming previous studies, our environmental niche models showed a decrease in available habitat during the Last Glacial Maximum, but we find no genetic signals of recent population declines in mitochondrial genomes despite both sustained habitat loss and a commercial whaling bottleneck. Our results illustrate the complex dynamics of baleen whale biogeography since the Holocene as well as the difficulty in detecting recent demographic bottlenecks from mitochondrial DNA sequences.

Measuring wildlife responses to anthropogenic activities often requires long‐term, large‐scale datasets that are difficult to collect. This is particularly true for rare or cryptic species, which includes many mammalian carnivores. Citizen science, in which members of the public participate in scientific work, can facilitate collection of large datasets while increasing public awareness of wildlife research and conservation. Hunters provide unique benefits for citizen science given their knowledge and interest in outdoor activities. We examined how anthropogenic changes to land cover impacted relative abundance of two sympatric canids, coyote (Canis latrans), and red fox (Vulpes vulpes) at a large spatial scale. In order to assess how land cover affected canids at this scale, we used citizen science data from bow hunter sighting logs collected throughout New York State, USA, during 2004–2017. We found that the two species had contrasting responses to development, with red foxes positively correlated and coyotes negatively correlated with the percentage of low‐density development. Red foxes also responded positively to agriculture, but less so when agricultural habitat was fragmented. Agriculture provides food and denning resources for red foxes, whereas coyotes may select forested areas for denning. Though coyotes and red foxes compete in areas of sympatry, we did not find a relationship between species abundance, likely a consequence of the coarse spatial resolution used. Red foxes may be able to coexist with coyotes by altering their diets and habitat use, or by maintaining territories in small areas between coyote territories. Our study shows the value of citizen science, and particularly hunters, in collection of long‐term data across large areas (i.e., the entire state of New York) that otherwise would unlikely be obtained., We examined how anthropogenic changes to land cover impacted relative abundance of two sympatric canids, coyote (Canis latrans), and red fox (Vulpes vulpes) at a large spatial scale. We found that the two species had contrasting responses to development, with red foxes positively correlated and coyotes negatively correlated with the percentage of low‐density development. Red foxes also responded positively to agriculture, but less so when agricultural habitat was fragmented.

With efforts to restore large mammal populations following extirpations, it is vital to quantify how they are impacted by human activities and gain insights into population dynamics in relation to conservation goals. Our objective was to characterize cause-specific mortality of black bears (Ursus americanus) throughout their range. We first quantified cause-specific mortality for 247 black bears in one harvested and two non-harvested populations. We then simulated a small recolonizing population with and without anthropogenic mortality. Lastly, we conducted a meta-analysis of all published black bear mortality studies throughout North America (31 studies of 2630 bears). We found anthropogenic mortality was greater than natural mortality, non-harvest anthropogenic mortality (e.g. poaching, defense of property, etc.) was greater in non-harvested populations, and harvesting was one of the major causes of mortality for bears throughout their range. Our simulation indicated that removing anthropogenic mortality increased population size by an average of 23% in 15 years. We demonstrated that bears are exposed to high levels of anthropogenic mortality, and the potential for human activities to slow population growth in expanding populations. Management and conservation of wide-ranging mammals will depend on holistic strategies that integrate ecological factors with socio-economic issues to achieve successful conservation and coexistence.

Free-ranging large carnivores are involved in human-wildlife conflicts which can result in economic costs. Understanding factors that lead to human-wildlife conflicts is important to mitigate these negative effects and facilitate human-carnivore coexistence. We used a human-American black bear (Ursus americanus) conflict database maintained by the New York State Department of Environmental Conservation to determine whether drought, conflicts within the Adirondack and Catskill Parks as compared to outside of these parks, mild severity (Class 3) conflicts early in the year (April–June), and bear harvest in the previous year (as an index of bear abundance), were associated with greater frequency of high or moderate severity (Class 1–2) conflicts later in the year (July–September) across New York, USA. During 2006–2019, we obtained 3,782 mild severity conflict records early in the year, and 1,042 high or moderate severity records later in the year. We found that a one standard deviation increase in the cumulative precipitation difference from mean early in the year (about 7.59 cm) coincided with a 20% decrease in conflicts, and that Wildlife Management Units (WMUs) within the parks were predicted to have 5.61 times as many high or moderate severity conflicts as WMUs outside the parks. We also found that a one standard deviation increase in the frequency of mild severity conflicts (equivalent to 5.68 conflicts) early in the year coincided with an increase in the frequency of high or moderate severity conflicts in a WMU later in the year by 49%, while a one standard deviation increase in the bear abundance index in the previous year (0.14 bears/10 km2) coincided with a 23% increase in high or moderate severity conflicts. To reduce the frequency and severity of conflicts to facilitate human-black bear coexistence, we recommend the following measures to be taken in place consistently and build over time in local communities: (i) further reducing black bear access to anthropogenic foods and other attractants, (ii) non-lethal measures including bear-resistant waste management, (iii) electric fencing, and (iv) modifying placement or configuration of field crops.

Wildlife monitoring programs are instrumental for the assessment of species, habitat status, and for the management of factors affecting them. This is particularly important for species found in freshwater ecosystems, such as amphibians, as they have higher estimated extinction rates than terrestrial species. We developed and validated two species-specific environmental DNA (eDNA) protocols and applied them in the field to detect the Hazara Torrent Frog (Allopaa hazarensis) and Murree Hills Frog (Nanorana vicina). Additionally, we compared eDNA surveys with visual encounter surveys and estimated site occupancy. eDNA surveys resulted in higher occurrence probabilities for both A. hazarensis and N. vicina than for visual encounter surveys. Detection probability using eDNA was greater for both species, particularly for A. hazarensis. The top-ranked detection model for visual encounter surveys included effects of both year and temperature on both species, and the top-ranked occupancy model included effects of elevation and year. The top-ranked detection model for eDNA data was the null model, and the top-ranked occupancy model included effects of elevation, year, and wetland type. To our knowledge, this is the first time an eDNA survey has been used to monitor amphibian species in the Himalayan region.

More than 25% of species assessed by the International Union for Conservation of Nature (IUCN) are threatened with extinction. Understanding how environmental and biological processes have shaped genomic diversity may inform management practices. Using 68 extant avian species, we parsed the effects of habitat availability and life-history traits on genomic diversity over time to provide a baseline for conservation efforts. We used published whole-genome sequence data to estimate overall genomic diversity as indicated by historical long-term effective population sizes (Ne) and current genomic variability (H), then used environmental niche modelling to estimate Pleistocene habitat dynamics for each species. We found thatNeandHwere positively correlated with habitat availability and related to key life-history traits (body mass and diet), suggesting the latter contribute to the overall genomic variation. We found thatHdecreased with increasing species extinction risk, suggesting thatHmay serve as a leading indicator of demographic trends related to formal IUCN conservation status in birds. Our analyses illustrate that genome-wide summary statistics estimated from sequence data reflect meaningful ecological attributes relevant to species conservation.

The parallel niche release hypothesis (PNR) indicates that reduced competition with dominant competitors results in greater density and niche breadth of subordinate competitors and which may support an adaptive advantage.We assessed support for the PNR by evaluating relationships between variation in niche breadth and intra- and interspecific density (an index of competition) of wolves (

Recent increases in turkey vulture (Cathartes aura) and black vulture (Coragyps atratus) populations in North America have been attributed in part to their success adapting to human-modified landscapes. However, the capacity for such landscapes to generate favorable roosting conditions for these species has not been thoroughly investigated. We assessed the role of anthropogenic and natural landscape elements on roosting habitat selection of 11 black and 7 turkey vultures in coastal South Carolina, USA using a GPS satellite transmitter dataset derived from previous research. Our dataset spanned 2006–2012 and contained data from 7916 nights of roosting. Landscape fragmentation, as measured by land cover richness, influenced roosting probability for both species in all seasons, showing either a positive relationship or peaking at intermediate values. Roosting probability of turkey vultures was maximized at intermediate road densities in three of four seasons, and black vultures showed a positive relationship with roads in fall, but no relationship throughout the rest of the year. Roosting probability of both species declined with increasing high density urban cover throughout most of the year. We suggest that landscape transformations lead to favorable roosting conditions for turkey vultures and black vultures, which has likely contributed to their recent proliferations across much of the Western Hemisphere.

Genomic diversity is the evolutionary foundation for adaptation to environmental change and thus is essential to consider in conservation planning. Island species are ideal for investigating the evolutionary drivers of genomic diversity, in part because of the potential for biological replicates. Here, we use genome data from 180 individuals spread among 27 island populations from 17 avian species to study the effects of island area, body size, demographic history and conservation status on contemporary genomic diversity. Our study expands earlier work on a small number of neutral loci to the entire genome and from a few species to many. We find significant positive correlation between island size and genomic diversity, a significant negative correlation between body size and genomic diversity, and that historical population declines significantly reduced contemporary genomic diversity. Our study shows that island size is the key factor in determining genomic diversity, indicating that habitat conservation is key to maintaining adaptive potential in the face of global environmental change. We found that threatened species generally had a significantly smaller values of Watterson's theta (θW = 4Ne μ) compared to nonthreatened species, suggesting that θW may be useful as a conservation indicator for at-risk species. Overall, these findings (a) provide biological insights into how genomic diversity scales with ecological, morphological and demographic factors; and (b) illustrate how population genomic data can be leveraged to better inform conservation efforts.

Many small mammal populations respond quickly to timber harvest aimed at oak (Quercus) regeneration, which alters microhabitat. We used mark-release–recapture data collected 6–8 years postharvest from the Hardwood Ecosystem Experiment in southern Indiana, United States, to model density and apparent survival of eastern chipmunks (Tamias striatus) and white-footed mice (Peromyscus leucopus) as a function of timber harvest treatments (shelterwood, clearcut, patch cut, and unharvested control). Density, estimated using spatial capture–recapture, increased for chipmunks in all types of harvest openings, but survival was unaffected by harvest. Chipmunk densities in unharvested forest matrix habitat averaged 58% and 71% lower relative to harvest openings and opening edges, respectively. White-footed mouse density was less responsive to timber harvest, but monthly survival rates were reduced by 13% in shelterwoods and 17% in patch cuts relative to control sites. Both rodent species tended to exhibit distance-dependent responses, with higher density of home-range centers near harvest boundaries relative to forest matrix. Structural complexity created at the edges of timber harvest openings can benefit rodents associated with edge habitat 6–8 years after harvest, presumably due to improved foraging efficiency and resource diversity. Cascading effects of rodent demographic responses are likely to affect predation and seed dispersal, which are critical trophic interactions in oak forest ecosystems.

Wildlife species differ in their resistance to landscape modifications including habitat loss and fragmentation. We hypothesized that niche breadth is positively related to both (1) overall species occurrence and (2) species response to landscape modification, because species with a wide range of diet and/or habitat preferences should be able to colonize and survive in more patches than specialized species. We tested the hypothesis using occurrence data from 65 species spanning multiple taxonomic groups (birds, small mammals, bats, and aquatic turtles) collected in thirty-five 23 km2 landscapes in the Midwestern United States that varied in degree of modification. Niche breadth for each species was obtained from a combination of sources on habitat and diet requirements. We fit models for occurrence and response to modification as a function of niche breadth while accounting for imperfect detection and phylogenetic relatedness among species. As predicted, niche breadth was positively related to occurrence for all taxonomic groups. Response to landscape modification was positively related to niche breadth for birds, but there was no effect for the other taxonomic groups. Neither imperfect detection nor phylogeny affected relationships qualitatively. The lack of an effect of niche breadth on response to modification may be due to a long history of human land-use in the study region, resulting in assemblages in which all extant species have at least some resistance to agricultural disturbance.

Understanding the types and magnitude of human-caused mortality is essential for maintaining viable large carnivore populations. We used a database of cause-specific mortality to examine how hunting regulations and landscape configurations influenced human-caused mortality of North American gray wolves (

Trophic cascades reportedly structure ecological communities through indirect species interactions. Though the predator-herbivore-autotroph relationship has received much attention, mechanistic evidence supporting intraguild trophic cascades is rare. We established 348 remote camera sites (1 August-5 September 2019) across seven study areas of varying wolf (Canis lupus) density including one study area where wolves were absent in northern Michigan, USA. Using multi-species occupancy modeling at species-relevant spatial scales, we evaluated the hypothesis that increased wolf occurrence suppresses coyote (C. latrans) occurrence with corresponding increased red fox (Vulpes vulpes) occurrence mediated by land cover edge density, human presence, and temporal partitioning. Remote cameras recorded >600,000 images and included 6,370, 10,137, and 4,876 detections of wolves, coyotes, and foxes, respectively. Fox occupancy probability was more than three times as high (0.29) at camera sites where wolves were present, relative to sites wolves were absent (0.09). Pairwise species interactions supported expected size-based dominance patterns among canids and insignificant effects were directionally consistent with reported reduced strength of top-down effects in peripheral wolf range. Increased edge density also increased co-occurrence of coyote and wolves, likely a function of increased prey availability and refugia for coyotes. Though foxes occurred in spatial proximity to wolves, competition was limited by greater temporal partitioning than observed between coyotes and foxes that were spatially segregated. Collectively, our results provide marginal support for the reported trophic cascade among wolves, coyotes, and foxes wherein top-down effects may be reduced near the edge of current wolf distributions. As predators continue to recolonize portions of their historic range, knowledge of the effects on intraguild predators has implications for species management and predicting prey population responses.

Multispecies occupancy models estimate dependence among multiple species of interest from patterns of co-occurrence, but problems associated with separation and boundary estimates can lead to unreasonably large estimates of parameters and associated standard errors when species are rarely observed at the same site or when data are sparse. In this paper, we overcome these issues by implementing a penalized likelihood, which introduces a small bias in parameter estimates in exchange for a potentially large reduction in variance. We compare parameter estimates obtained from both penalized and unpenalized multispecies occupancy models fit to simulated data that exhibit various degrees of separation and to a real-word data set of bird surveys with little apparent overlap between potentially interacting species. Our simulation results demonstrate that penalized multispecies occupancy models did not exhibit boundary estimates and produced lower bias, lower mean squared error, and improved inference relative to unpenalized models. When applied to real-world data, our penalized multispecies occupancy model constrained boundary estimates and allowed for meaningful inference related to the interactions of two species of conservation concern. To facilitate the use of our penalized multispecies occupancy model, the techniques demonstrated in this paper have been integrated into the unmarked package in R programing language.

Runs of homozygosity (ROHs) arise due the transmission from parents to offspring of segments that are either identical by decent (IBD) or identical by state (IBS). The former is due to consanguineous matings whereas the latter is due to demographic processes. ROHs reduce individual nucleotide diversity (θ) as a function of homozygosity, and thus ROH distributions and θ are expected to vary among species because inbreeding levels, recombination rates, and demographic histories vary widely. To help interpret genetic diversity within and among species, we utilized genome sequence data from 78 mammalian species to compare θ and ROH burden (i.e., number and length of ROHs in the genome) among groups of mammals to assess genomic signatures of inbreeding. We compared θ and ROHs: (i) among threatened and non-threatened mammals to determine the significance of contemporary conservation status; (ii) among carnivorous and non-carnivorous mammals to determine the relevance of trophic effects; (iii) relative to body size because mutation rates generally vary with body mass; and (iv) across mammals from different latitudes to test for gradients in genomic diversity (e.g., due to effects of historic climatic regimes). Our results illustrate the considerable variance in genomic diversity across mammals, and that trophic level, body mass, and latitude have significant effects on θ and ROH burden. However, conservation status was not a reliable indicator of genomic diversity. We argue that genetic or genomic diversity should be an explicit component of conservation status, as such diversity is critical to the long-term sustainability of populations, and anticipate that ROHs will become more commonly used to estimate inbreeding in wild animals.

The influence of forest fragmentation and associated habitat edges differentially affects forest-dependent organisms, particularly when certain species are able to use resources from surrounding matrix habitats. The white-footed mouse is a forest habitat generalist and is known to disperse among adjoining farmland habitats, including agricultural matrix, in fragmented agro-ecosystems. However, little is known about spatial variation in population density within adjoining farmland habitats or how this relationship varies seasonally. In addition quantifying the extent to which white-footed mice use agricultural matrix as habitat is important for inferring potential ecosystem services (predation of weed seed and waste grain) rendered within row-crop fields. We used spatially explicit capture-recapture models to estimate density of white-footed mice along a gradient of patch (forest fragment) interior to matrix (crop field) interior that spanned fragmented habitat edges. Spatial variation in populati...

Prairie deer mice ( Peromyscus maniculatus bairdii ) are permanent residents of row-crop fields in the Midwestern United Sates, and may provide ecosystem services by regulating weed seed and waste grain populations. Seed predation is especially critical in the months of highest seed availability following crop harvest, and is dictated by population density and individual patterns of diet choice. We used a combination of spatial mark-recapture demographic and stable isotope dietary analyses to investigate the ecology of prairie deer mice during this critical over-winter period within corn and soybean agro-ecosystems of west-central Indiana. Winter prairie deer mouse populations were robust in the row-crop habitats we sampled, with densities typically > 13 individuals/ha but variable among trapping grids and throughout winter. Apparent survival of individuals also varied throughout winter (57–79% monthly survival rate), and mean over-winter (December–April) survival of adults was 21%. Winter diets were dominated by waste grain, with corn and soybean contributing 55% and 77% of diet for mice sampled in corn and soybean fields, respectively. Weed seeds contributed less (2–27%) to winter diets. Based on our results and published field metabolic rates, we estimate that prairie deer mice consume 6.3 kg/ha of waste corn and 7.1 kg/ha of waste soybean seeds during the non-growing season. Collectively, our results suggest that prairie deer mice make meaningful contributions to reducing waste-grain populations during winter in post-harvest row-crop fields, during a time of year when most other seed predators are inactive.

In eastern North America, oak (Quercus) regeneration failure has spurred management using silvicultural approaches better aligned with the autecology of oaks. In particular, shelterwood harvests can create favorable intermediate light conditions for oak establishment and prescribed fire is predicted (by the oak-fire hypothesis) to favor oak regeneration. These approaches substantially modify forest structure and may affect crucial trophic interactions including the conditional mutualism between oaks and granivorous rodents that scatterhoard acorns, which shifts along a continuum from antagonistic to mutualistic depending on external factors. We investigated how overwinter survival and dispersal of northern red oak (Quercus rubra) acorns were influenced by location within or outside of group shelterwood harvests (small canopy gaps created throughout an intact forest stand) with and without prescribed fire. We conducted two concurrent experiments to test (1) dispersal and survival of acorns presented on the forest floor and (2) acorn pilferage rates from caches that mimic squirrel scatterhoards in shelterwood gap/group interiors, edges, and the uncut forest matrix in burned and unburned forest stands. In both experiments, acorn survival was generally higher in burned than unburned stands. Acorn survival from forest floor presentations was higher in the unharvested forest matrix than harvest gap interiors; however, there was no effect of proximity to harvest gaps on survival of cached acorns. Survival of cached acorns was associated with understory vegetative cover (-), coarse woody debris cover (-), and distance to nearest tree (+), but uncorrelated with canopy cover above the cache. Our results suggest that reduced understory cover following prescribed fire may increase perceived habitat riskiness for granivores resulting in higher acorn survival up to 2 yr post-fire. These findings unify the oak-fire and oak-granivore conditional mutualism hypotheses, and suggest that the environmental conditions following prescribed fire and group shelterwood harvests may shift the oak-granivore conditional mutualism in a direction beneficial for oak regeneration.

Modern forest management seeks to balance multiple social, economic, and ecological goals. Different management approaches create different types of disturbances in a forest ecosystem and thus also differ in their impacts on plants, animals, and insects. Understanding these impacts is important for conservation of forest ecosystem function, but challenging due to the large spatial and temporal scale over which management occurs. Most past research has focused on relatively small areas, short time scales, and/or a small number of species. To address this, we examined the effects of two common silvicultural systems (even and uneven aged) on abundance and richness of three vertebrate taxa (birds, small mammals, and herpetofauna) over a two-decade period in a temperate hardwood forest in Missouri, USA. The two systems removed a similar amount of biomass overall, but differed in the intensity, number, and configuration of harvests applied. We found that vertebrate population responses varied by taxa, occurred at multiple spatial scales, and were concentrated in the period following the first harvest entry. Birds generally had the largest changes in relative abundance, both positive and negative, following management. Small mammals and reptiles had smaller, but generally positive, responses; amphibians were mixed. Bird species tended to respond in the same way to both silvicultural systems, while small mammals and herpetofauna did not respond consistently. Thus, for birds, the total amount of harvest disturbance across the landscape drives population responses, while for others the size and configuration of individual harvests is likely more important. Synthesizing results across the vertebrate community at large spatial and temporal scales allows managers to better understand trade-offs when making decisions that will affect wildlife in contrasting ways.

Edge habitats create environmental gradients that affect plant community composition and herbivore behavior. Silvicultural disturbance creates edge habitat with direct (via changes in light) and indirect (via changes in herbivore behavior) consequences for the growth and survival of tree seedlings, and thus, the composition of the future forest stands. Herbivores, particularly ungulates, can be a major limiting factor in oak regeneration, and silvicultural disturbance may alter the abundance or behavior of herbivores following harvest. We measured the severity of herbivory on experimentally planted white (Quercus alba) and black oak (Quercus velutina) seedlings by white-tailed deer (Odocoileus virginianus) and eastern cottontail rabbits (Sylvilagus floridanus), as well as foliar damage from insects, across gradients created by clearcuts in a deciduous forest in Indiana, USA. Overall browse pressure on oaks was low in our study. Nonetheless, spatial variation in herbivory depended on herbivore taxa; herbivory by rabbits was highest inside harvest openings, whereas foliar damage by insects peaked in the forest. Intensity of deer herbivory was constant across the edge. In addition, we observed indirect interactions among herbivore species mediated by a seedling’s browsing history. Herbivore damage by deer was positively related to past browsing by rabbits, and foliar damage from insects was positively related to past browsing by both deer and rabbits. Increasing woody plant competition reduced herbivory on seedlings by both deer and rabbits. Given the lack of spatial variability in deer herbivory and low overall herbivory by rabbits, we suspect that interactions between timber harvesting and herbivory did not have a strong impact on oak seedlings at our study sites.

Timber harvests that aim to promote oak (Quercus) regeneration may have indirect impacts on seedling recruitment by altering trophic interactions between oak and animals. For example, changes in habitat structure following harvest may alter the conditionally mutualistic relationship between oak and small mammal granivores like the gray squirrel (Sciurus carolinensis), eastern chipmunk (Tamias striatus) and white-footed mouse (Peromyscus leucopus) that act both as acorn predators and as dispersers. Over 4 years (2010–2013), we tracked the fate of a total of 8000 tagged acorns placed beneath black (Quercus velutina) and white oaks (Quercus alba) at 5 control (unharvested) sites and 5 sites where the midstory was removed as part of a three-phase shelterwood harvest in an oak-dominated forest in southern Indiana, USA. We found that acorns in harvested sites were more likely to be taken by granivores and were less likely to survive the winter, resulting in an overall 67% reduction in seed dispersal effectiveness (SDE). Harvested sites had more vegetative cover and coarse woody debris in the understory, providing increased cover from aerial predators and potentially facilitating greater acorn removal and a higher probability of cache recovery. Reduced seed dispersal effectiveness following midstory removal has potential to slow accumulation of oak regeneration prior to overstory removal and therefore to reduce the effectiveness of shelterwood treatments in promoting future oak dominance in harvested stands. Augmentation of shelterwoods with prescribed fire or other treatments to reduce understory density may counter this effect.