Research Interests
I am broadly interested in how wildlife species and communities respond to habitat alteration caused by humans. In order to effectively manage wildlife populations in the face of human disturbances, we must first understand the mechanisms underlying species and community responses. Much of my previous work has focused on responses to one specific type of human disturbance: energy development, though I am alo interested in species responses to urbanization, land conversion for agriculture, and deforestation.
Past and Current Research
Population dynamics of forest grouse
The landscapes of the western US have been increasingly altered by logging, increased wildfire prevalence/intensity, and urbanization in the past 100 years. Understanding how these habitat changes affect wildlife species is becoming increasingly important. This is particularly true for game species, like forest grouse. Without a sold understanding of their population dynamics and distribution, state agencies cannot make informed decisions on the number of hunting tags to issue each year. We aim to document forest grouse population trends throughout Western Oregon, and to gain a better understanding of forest grouse vocalizations and behavior during the breeding season.
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Research status: ongoing
Effects of extreme weather on avian productivity
Weather patterns are increasingly being altered by contemporary climate change, with temperate regions regularly experiencing more temperature extremes and storm events. Understanding of how avian species are affected by climatic changes under different contexts, however, is still in its infancy. Songbirds that breed in exposed, arid systems, continue to exhibit some of the steepest population declines and may be particularly vulnerable to extreme weather conditions. We are investigating the effect of variability in temperature and precipitation regimes on sagebrush-obligate songbird productivity, using ~6,000 nests monitored from 2002-2018 across western Wyoming. Productivity metrics of interest include: nest survival, # young fledged, nestling condition, breeding season lengths, incubation / brooding period lengths, and ectoparasite loads. Understanding the effect of novel climatic conditions on vulnerable species during key life stages will be critical as more extreme weather patterns continue to manifest.
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Research status: ongoing
Photo: T. Scherr
Mechanisms underlying increased nest predation within gas fields
Habitat loss and alteration resulting from human activities are affecting wildlife species around the globe. Mechanisms underlying such effects are rarely investigated or known, yet are critical for effective mitigation. Previous work has identified increased nest predation for sagebrush-obligate songbirds and increased nest predator (i.e. rodent) abundance associated with surface disturbance from natural gas development. We investigated potential mechanisms driving this pattern by testing two alternative hypotheses. We found support for a risk-mediated foraging hypothesis, whereby nest predators were generally in poorer fitness near development, despite the increased food resources available there (within reclaimed areas surrounding energy infrastructure)—likely a product of increased predation risk associated with energy development. Our results clarified the important role reclaimed areas play as a food resource for nest predators on energy fields, and provided specific suggestions for how natural gas developers and land managers may adjust practices to mitigate the negative effects of development on co-occurring songbirds of concern.
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Read published research on this topic:
Sanders, L.E. and A.D. Chalfoun. 2019. Mechanisms underlying increased nest predation in natural gas fields: a test of the mesopredator release hypothesis. Ecosphere, 10(5): e02738. PDF
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Sanders, L.E. and A.D. Chalfoun. 2018. Novel landscape elements within natural gas fields increase densities of an important songbird nest predator. Biological Conservation, 228: 132-141. PDF
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Media coverage of this research:
University of Wyoming, alumni magazine
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Check out our project website for more information
Research status: complete
Photo: K. Harkins
Energy fields as ecological traps for nesting songbirds
Our previous research efforts on sagebrush-obligate songbirds breeding near energy development have demonstrated increased nest predation in areas of high density development. We wanted to delve deeper into this pattern, however, to investigate questions such as 1) are natural gas fields serving as an ecological trap for nesting songbirds (i.e. do birds recognize the threat posed by development when settling territories early in the breeding season)?, 2) are songbirds able to mediate some negative effects of development via their choice of micro-habitat at nesting sites?, and 3) what specific aspects of surface disturbance from energy development (i.e. roads, well pads, pipelines, reclaimed areas) are most influential for the nest survival of breeding songbirds? We utilized a dataset of ~2,500 nests monitored from 2008-2019 to assess these and additional questions relating to avian productivity on energy fields.
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Research status: ongoing
Photo: T. Scherr
Raptor nest-site use in relation to the proximity of coalbed-methane development
Energy development such as coalbed–methane (CBM) extraction is a major land use with largely unknown consequences for many animal species. Some raptor species may be especially vulnerable to habitat changes due to energy development given their ecological requirements and population trajectories. Using ~3,000 nests of 12 raptor species monitored from 2003–2011 in the Powder River Basin, Wyoming, USA, we evaluated relationships between raptor nest–site use and CBM development. In collaboration with the BLM, our objectives were to determine temporal trends in nest–use rates, and whether nest–site use was related to the proximity of CBM development.
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See published research on this topic:
Carlisle, J., L. Sanders, A. Chalfoun and K. Gerow. 2018. Raptor nest-site use in relation to the proximity of coalbed-methane development. Animal Biodiversity and Conservation, 41(2):227-243. PDF
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Check out our project website for more information
Research status: complete
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