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Animal carcass decomposition is an often-overlooked component of nutrient cycles. The importance of carcass decomposition for increasing nutrient availability has been demonstrated in several ecosystems, but impacts in arid lands are poorly understood. In a protected high desert landscape in Argentina, puma predation of vicuñas is a main driver of carcass distribution. Here, we sampled puma kill sites across three habitats (plains, canyons, and meadows) to evaluate the impacts of vicuña carcass and stomach decomposition on soil and plant nutrients up to 5 years after carcass deposition. Soil beneath both carcasses and stomachs had significantly higher soil nutrient content than adjacent reference sites in arid, nutrient-poor plains and canyons, but not in moist, nutrient-rich meadows. Stomachs had greater effects on soil nutrients than carcasses. However, we did not detect higher plant N concentrations at kill sites. The biogeochemical effects of puma kills persisted for several years and increased over time, indicating that kills do not create ephemeral nutrient pulses, but can have lasting effects on the distribution of soil nutrients. Comparison to broader spatial patterns of predation risk reveals that puma predation of vicuñas is more likely in nutrient-rich sites, but carcasses have the greatest effects on soil nutrients in nutrient-poor environments, such that carcasses increase localized heterogeneity by generating nutrient hotspots in less productive environments. Predation and carcass decomposition may thus be important overlooked factors influencing ecosystem functioning in arid environments.

Same-sex sexual behaviour (SSB) has been recorded in over 1,500 animal species with a widespread distribution across most major clades. Evolutionary biologists have long sought to uncover the adaptive origins of ‘homosexual behaviour’ in an attempt to resolve this apparent Darwinian paradox: how has SSB repeatedly evolved and persisted despite its presumed fitness costs? This question implicitly assumes that ‘heterosexual’ or exclusive different-sex sexual behaviour (DSB) is the baseline condition for animals, from which SSB has evolved. We question the idea that SSB necessarily presents an evolutionary conundrum, and suggest that the literature includes unchecked assumptions regarding the costs, benefits and origins of SSB. Instead, we offer an alternative null hypothesis for the evolutionary origin of SSB that, through a subtle shift in perspective, moves away from the expectation that the origin and maintenance of SSB is a problem in need of a solution. We argue that the frequently implicit assumption of DSB as ancestral has not been rigorously examined, and instead hypothesize an ancestral condition of indiscriminate sexual behaviours directed towards all sexes. By shifting the lens through which we study animal sexual behaviour, we can more fruitfully examine the evolutionary history of diverse sexual strategies. The authors hypothesize an ancestral condition of indiscriminate sexual behaviours directed towards all sexes, rather than a state in which different-sex sexual behaviour is a baseline and same-sex sexual behaviour is anomalous.

Shorebird populations worldwide are declining because of habitat loss from sea-level rise, accelerated erosion, development, and recreational land use. To better understand the consequences of human recreational activity, we monitored survival, habitat use, condition, and behavior of pre-fledged piping plover (Charadrius melodus) chicks on Fire Island and Westhampton Island, New York, 2013–2015. Broods experienced varying levels of recreational land use (low-use, moderate-use, high-use, and high off-road vehicle-use), and recreational use was higher on weekends (Friday–Sunday) than weekdays. Chick daily survival rates were lowest on weekends and increased with time since weekend. Chicks that hatched in areas with low recreational use were more likely to survive to fledging (25 days; x̄ = 0.82 ± 0.08 SE) than those that hatched in areas of high recreational use (x̄ = 0.19 ± 0.05). In addition, chicks hatched in areas of high recreational use fledged at a later age than those hatched in areas of low or moderate recreational use. On weekends, chicks spent less time in foraging habitat (with higher prey abundance), less time foraging, and made fewer foraging attempts per minute than they did on weekdays. These results suggest that recreational activity on beaches pushed foraging plover chicks into habitats with lower food availability, resulting in lower feeding rates, slower growth, and decreased survival. Recreational use of coastal areas can limit the functional availability of shorebird foraging habitat, particularly intertidal foraging habitat, resulting in demographic consequences.

The emerging field of eco-evolutionary dynamics has demonstrated that both ecological and evolutionary processes can occur contemporaneously. Ecological interactions, such as between predator and prey, are important focal areas where an eco-evolutionary perspective can advance understanding about phenotypically plastic and adaptive evolutionary responses. In predator-prey interactions, both species reciprocally respond and adapt to each other in order to simultaneously ensure resource consumption and predation avoidance. Here we sketch out a way to help unify experimental and analytical approaches to both eco-evolutionary dynamics and predator-prey interactions, with a specific focus on terrestrial systems. We discuss the need to view predator-prey eco-evolutionary dynamics as a perpetually adaptive interplay with constantly shifting pressures and feedbacks, rather than viewing it as driving a set evolutionary trajectory. We then outline our perspective on how to understand eco-evolutionary patterns in a predator-prey context. We propose initiating insight by distinguishing phenotypic plasticity against genetic change ( , \"molecular reductionism\") and further applying a landscape-scale perspective ( , \"landscape holism\"). We believe that studying predator-prey interactions under an eco-evolutionary lens can provide insights into how general and, consequently, predictable species' evolutionary responses are to their contemporary environments.

A meta-analysis of research on megaherbivore effects on ecosystems shows that large wild mammals influence heterogeneity in plant, soil and animal community responses.

Conservation of shorebirds throughout their breeding and migratory ranges has become a priority as shorebird populations decline globally. Along the North Atlantic Coast, management efforts have particularly focused on preserving nesting habitat for piping plovers (Charadrius melodus), which are protected under the Endangered Species Act. It is unclear whether these conservation measures suffice to protect foraging habitat for piping plovers and other shorebirds on stopover during migration along the Atlantic Flyway. To evaluate the extent to which conservation of piping plover nesting areas extends to all habitats used by plovers, and to determine whether these protections also benefited non-breeding migratory shorebirds in the region, we conducted weekly shorebird surveys, recording the number and locations of piping plovers and other species, during northward and southward migration on Fire Island and Westhampton Island, New York, USA, from 2014–2016. We used canonical correspondence analysis (CCA) to assess the degree of spatiotemporal overlap between breeding plovers, foraging plovers, and other migratory shorebirds that temporarily stage at the site. The spatiotemporal distribution of migratory shorebirds matched more closely with piping plovers seen during foraging than piping plovers observed tending nests and engaging in other breeding activities. Migratory shorebirds and foraging piping plovers were more abundant and frequent in wet intertidal zones outside of fenced-off nesting areas, which were not protected under current management regimes. Therefore, additional protection of piping plover foraging habitat could benefit plovers and migratory shorebirds that use similar feeding grounds during stopover on northward and southward migration.

In-scanner head motion introduces systematic bias to resting-state fMRI functional connectivity (FC) not completely removed by denoising algorithms. Researchers studying traits associated with motion (e.g. psychiatric disorders) need to know if their trait-FC relationships are impacted by residual motion to avoid reporting false positive results. We devised Split Half Analysis of Motion Associated Networks (SHAMAN) to assign a motion impact score to specific trait-FC relationships. SHAMAN distinguishes between motion causing overestimation or underestimation of trait-FC effects. We assessed 45 traits from n  = 7270 participants in the Adolescent Brain Cognitive Development (ABCD) Study. After standard denoising with ABCD-BIDS and without motion censoring, 42% (19/45) of traits had significant ( p  < 0.05) motion overestimation scores and 38% (17/45) had significant underestimation scores. Censoring at framewise displacement (FD) < 0.2 mm reduced significant overestimation to 2% (1/45) of traits but did not decrease the number of traits with significant motion underestimation scores. Head motion is an artifact in structural and functional MRI signals, and some traits or groups are more strongly correlated with motion than others. Here the authors describe a method to attribute a motion impact score to specific trait-functional connectivity relationships.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Between April 2014 and August 2015, we observed 4 Charadrius melodus (Piping Plover) consume small, dead fish, including Anchoa mitchilli (Bay Anchovy) on New York barrier islands. These observations are among the first documented evidence of vertebrate prey in Piping Plover diets. While fish consumption is an opportunistic and infrequent occurrence, this behavior may supplement important nutrients in the diet of Piping Plovers in areas without access to high-quality food resources. Further diet analyses are necessary to understand the importance and relative contribution of fish as a prey resource for endangered Piping Plovers.