Mechanisms underlying increased nest predation in natural gas fields: a test of the mesopredator release hypothesis

Lindsey E. Sanders; Anna D. Chalfoun

doi:10.1002/ecs2.2738

Home/Archive/USGS

USGS · 70223346

Mechanisms underlying increased nest predation in natural gas fields: a test of the mesopredator release hypothesis

Lindsey E. Sanders·Anna D. Chalfoun

View original source ↗Export metadata ↓

Abstract

Anthropogenic activities are changing landscapes and the context in which predator–prey dynamics evolved, thereby altering key ecological processes and community structure. Yet, the specific mechanisms underlying such changes are rarely understood. We tested whether a mesopredator release explained increased rodent density and concomitant predation of songbird nests near natural gas development. From 2015 to 2016, we surveyed apex predators (coyotes, badgers, raptors, and corvids) and measured apparent survival and perceived predation risk of deer mice ( Peromyscus maniculatus ; a primary nest predator), at 12 plots spanning a gradient of surface disturbance caused by energy development in Wyoming, USA. Additionally, we measured densities of three nest predators: deer mice, least chipmunks ( Tamias minimus ), and thirteen-lined ground squirrels ( Ictidomys tridecemlineatus ). Contrary to the mesopredator release hypothesis, counts of apex predators and perceived predation risk of deer mice increased with surface disturbance from energy development, whereas apparent survival of mice decreased. Densities of mice and ground squirrels, however, increased with surface disturbance, despite increased predation pressure. We therefore rejected the mesopredator release hypothesis as a potential mechanism underlying altered trophic dynamics near energy development. Our results suggest that apex predator control measures would not benefit declining songbirds on natural gas fields. Rather, apex predator abundance may be regulated from the bottom-up by rodents in this system. Our results corroborate a pattern showing weakened effects of mesopredator release in habitats modified by humans. Understanding how predator–prey dynamics may be altered in novel environments requires an understanding of how predators and prey alike respond to habitat change under different contexts.

Explore related subjects

Ecosphere Article

Source-reported bounding extent: 40.994746° to 45.005904° latitude; -111.056888° to -104.05216° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Lindsey E. Sanders, Anna D. Chalfoun. 2019-05-15. Mechanisms underlying increased nest predation in natural gas fields: a test of the mesopredator release hypothesis. https://doi.org/10.1002/ecs2.2738

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related USGS reports

USGS2026

Fire regime shift reveals 17th century socio-ecological change in the Rio Grande del Norte National Monument, New Mexico

Humans have influenced ecosystems for millennia, and social changes can have notable ecological effects. Recent human influence on ecosystems is exemplified by the collapse of fire regimes circa 1900 in the western United States due to increased grazing, fire suppression, and declining Indigenous fire use. Climate can also drive fire regime changes, which is reflected by increasing area burned across the West in recent decades associated with warming and increased aridity. In the southwestern United States during the mid-1600s, large social changes accompanied Spanish colonization. These changes included increases in domestic livestock (e.g., sheep and horses), declines of Indigenous populations and cultural burning, and exploitation of Puebloans that led to the 1680 Pueblo Revolt, an Indigenous uprising that expelled Spanish colonizers for 12 years. The ecological effects of these large social changes are not well studied. The goal of this study was to use tree-ring fire histories to investigate fire dynamics of a sagebrush-dominated landscape in the Rio Grande del Norte National Monument (RGDN) in northern New Mexico, including the effects of historical social and climatic changes. We reconstructed fire history on four forested mountains that rise above the sagebrush/grass plateau. We asked: (1) What was the pre-1900 fire frequency, season, and fire–climate relationship in the RGDN? (2) Was there evidence for fire spread in the sagebrush/grass flats between the mountains? and (3) Did regional social or climate changes influence fire regimes? From 1400 to 1679, we found frequent fire within forests (8–12-year median fire intervals [mfi]) and potential evidence of spreading fire through the sagebrush/grass ecosystem based on greater-than-expected intermountain fire synchrony. However, beginning in the mid-1600s and continuing after the Pueblo Revolt of 1680, there was (1) a significant decline in fire frequency, including 38–166-year mfi and no fire for >350 years at two sites; and (2) only one synchronous fire between mountains. During this 17th century period of socio-ecological change there was no persistent shift in climate. We propose that reduced Indigenous ignitions and increased domestic grazing, which reduced herbaceous fuels and fire spread, are likely causes of the extraordinary early and persistent reduction in fire.

New Mexico↗

USGS2026

Climate-driven changes in wetland hydroperiods predict losses in habitat suitability for amphibian breeding

Environmental regimes are shifting with accelerating climate change, disrupting interactions between species and ecosystems shaped by the climate of the pre-industrial era. Species assemblages that depend on a dynamic network of ephemeral and permanent habitats may be especially sensitive to changing climate, whereby shifting environmental regimes may limit species persistence in landscapes in ways not captured by species physiology or coarse habitat metrics alone. Here we forecasted the loss of montane and subalpine wetlands as breeding habitat for three amphibian species in the US Pacific Northwest, Ambystoma gracile , Ambystoma macrodactylum , and Rana cascadae . We combined historical and recent surveys to build occupancy models of current breeding habitat use. We combined these results with existing hydrological models to predict the loss of suitable breeding habitats by the 2080s due to increased wetland drying. We found that species-specific occupancy of wetlands used for reproduction was predicted by both abiotic (e.g., elevation, wetland area) and biotic (e.g., emergent vegetation) site-level characteristics. Among wetlands currently used for reproduction, we estimated that between 12% and 23% could become unsuitable for the aquatic phase of each species by the 2080s, with watershed-scale losses ranging from 0% to 80%. This suggests that wetland habitat loss could limit the persistence of these species in the Pacific Northwest, though impacts are expected to vary across landscapes. More broadly, we demonstrate a novel approach to quantifying species climate change vulnerability that can be used to identify areas of both risk and resilience in changing landscapes and help to prioritize the application of practical conservation solutions in areas of greatest need.

Washington↗

USGS2026

Sex-specific reproductive investment and survival of adult Atlantic salmon kelts across multiple dams

In adult Atlantic salmon, individual variation in migration and movement within rivers during spawning (i.e., reproductive movement, RM) is an important component of overall reproductive investment that may influence subsequent survival and repeat spawning. We test the cost-of-reproduction hypothesis—which states that increased reproductive investment decreases survival—by first quantifying individual RM of landlocked Atlantic salmon and then evaluating how RM, sex, and dams influence outmigration survival. Consistent with sexual selection for male mobility, male RM was ~4 times greater than that of females: they moved further, were more exploratory, visited a tributary more, went further upstream, and spent longer in the river. Results provide mixed support for a cost of RM on outmigration survival: individuals (inclusive of both sexes) that abandoned spawning and migrated downstream (i.e., “fallbacks”) survived 3.5-fold better than those that spawned (supporting an overall cost-of reproduction). However, males (with higher RM) had 2.8 times higher survival than females, and among males there was no effect of RM on survival (not-supporting a cost-of-RM). The most influential factor on survival was dam interactions, which reduced per-kilometer survival 18-fold relative to migration within free-flowing reaches. Documenting male-biased survival was unexpected given the (1) high RM of males and (2) that most prior studies find higher outmigration survival of female Atlantic salmon. We highlight how dams exacerbate the already high costs of reproduction in Atlantic salmon, which has important implications for contemporary evolution of behavioral tradeoffs.

Vermont↗