Life Sciences Commons^™

Perilous Choices: Landscapes Of Fear For Adult Birds Reduces Nestling Condition Across An Urban Gradient, Aaron M. Grade, Susannah B. Lerman, Paige S. Warren

Environmental Conservation Faculty Publication Series

Predator fear effects influence reproductive outcomes in many species. In non-urban systems, passerines often respond to predator cues by reducing parental investment, resulting in smaller and lighter nestlings. Since trophic interactions in urban areas are highly altered, it is unclear how passerines respond to fear effects in human-altered landscapes. Nestlings of passerines in urban areas also tend to be smaller and lighter than their rural counterparts and are often exposed to high densities of potential predators yet experience lower per capita predation-the predation paradox. We suggest fear effects in urban habitats could be a significant mechanism influencing nestling condition in …

An Empirical Demonstration Of The Effect Of Study Design On Density Estimations, Muhammad Ali Nawaz, Barkat Ullah Khan, Amer Mahmood, Muhammad Younas, Jaffar Ud Din, Chris Sutherland

Environmental Conservation Faculty Publication Series

The simultaneous development of technology (e.g. camera traps) and statistical methods, particularly spatially capture-recapture (SCR), has improved monitoring of large mammals in recent years. SCR estimates are known to be sensitive to sampling design, yet existing recommendations about trap spacing and coverage are often not achieved, particularly for sampling wide-ranging and rare species in landscapes that allow for limited accessibility. Consequently, most camera trap studies on large wide-ranging carnivores relies on convenience or judgmental sampling, and often yields compromised results. This study attempts to highlight the importance of carefully considered sampling design for large carnivores that, because of low densities …

Diversity-Production Relationships Of Fish Communities In Freshwater Stream Ecosystems, Bonnie J. E. Myers, C. Andrew Dolloff, Jackson R. Webster, Keith H. Nislow, Andrew L. Rypel

Environmental Conservation Faculty Publication Series

Aim Ecological relationships between species richness and biomass production are increasingly thought to be pervasive across the globe. Yet, diversity-production relationships have not been explored extensively for freshwater fish communities even though fisheries production provides key services to humans. Our aim was to evaluate the diversity-production relationship of fish communities inhabiting freshwater streams across the Appalachian Mountain range and examine how diversity-production relationships varied across streams possessing different thermal signatures. Location Our study area included 25 freshwater stream ecosystems spanning from Vermont to North Carolina in the United States. Twenty sites were located in Maryland south to Tennessee and North …

Large-Scale Patterns Of Green Turtle Trophic Ecology In The Eastern Pacific Oceans, Jeffery A. Seminoff, Lisa M. Komoroske, Diego Amorocho, Randall Arauz, Didiher Chacón-Chaverrí, Nelly De Paz, Peter H. Dutton, Miguel Donoso, Maike Heidemeyer, Gabriel Hoeffer

Environmental Conservation Faculty Publication Series

Trophic position and niche width are fundamental components of a species' ecology, reflecting resource use, and influencing key demographic parameters such as somatic growth, maturation, and survival. Concepts about a species' trophic niche space have important implications for local management and habitat protection, and can shed light about resilience to changing climate for species occurring over broad spatial scales. For elusive marine animals such as sea turtles, trophic niche is challenging to study, and researchers often rely on other metrics, such as isotopic niche, as a proxy. Here, stable isotope analysis (delta C-13 and delta N-15 values) was conducted on …

Functional Traits Linked To Pathogen Prevalence In Wild Bee Communities, Laura L. Figueroa, Sally Compton, Heather Grab, Scott H. Mcart

Environmental Conservation Faculty Publication Series

Reports of pollinator declines have prompted efforts to understand contributing factors and protect vulnerable species. While pathogens can be widespread in bee communities, less is known about factors shaping pathogen prevalence among species. Functional traits are often used to predict susceptibility to stressors, including pathogens, in other species-rich communities. Here, we evaluated the relationship between bee functional traits (body size, phenology, nesting location, sociality, and foraging choice) and prevalence of trypanosomes, neogregarines, and the microsporidian Nosema ceranae in wild bee communities. For the most abundant bee species in our system, Bombus impatiens, we also evaluated the relationship between intra-specific size …

Species And Population Specific Gene Expression In Blood Transcriptomes Of Marine Turtles, Shreya M. Banerjee, Jamie Adkins Stoll, Camryn D. Allen, Jennifer M. Lynch, Heather S. Harris, Lauren Kenyon, Richard E. Connon, Eleanor J. Sterling, Eugenia Naro-Maciel, Kathryn Mcfadden

Environmental Conservation Faculty Publication Series

Background: Transcriptomic data has demonstrated utility to advance the study of physiological diversity and organisms' responses to environmental stressors. However, a lack of genomic resources and challenges associated with collecting high-quality RNA can limit its application for many wild populations. Minimally invasive blood sampling combined with de novo transcriptomic approaches has great potential to alleviate these barriers. Here, we advance these goals for marine turtles by generating high quality de novo blood transcriptome assemblies to characterize functional diversity and compare global transcriptional profiles between tissues, species, and foraging aggregations.ResultsWe generated high quality blood transcriptome assemblies for hawksbill (Eretmochelys imbricata), loggerhead …

Annual Winter Water-Level Drawdowns Influence Physical Habitat Structure And Macrophytes In Massachusetts, Usa, Lakes, Jason R. Carmignani, Allison H. Roy

Environmental Conservation Faculty Publication Series

Annual wintertime water-level drawdowns are a common management strategy in recreational lakes; however, few studies have estimated their relative impact on lake littoral habitat among a set of typically co-occurring anthropogenic stressors including lakeshore development and herbicide application. Within 21 Massachusetts, USA lakes that represented a drawdown magnitude gradient (0.07-2.26 m), we assessed depth-specific littoral habitat (coarse wood, sediment, macrophytes) at two sites adjacent to forested or developed shorelines. Using generalized linear mixed models, we found coarse wood abundance and branching complexity was not correlated with drawdown magnitude but was primarily explained by the presence of lakeshore development. Drawdown magnitude …

The Value Of Considering Demographic Contributions To Connectivity: A Review, Joseph Drake, Xavier Lambin, Chris Sutherland

Environmental Conservation Faculty Publication Series

Connectivity is a central concept in ecology, wildlife management, and conservation science. Understanding the role of connectivity in determining species persistence is increasingly important in the face of escalating anthropogenic impacts on climate and habitat. These connectivity augmenting processes can severely impact species distributions and community and ecosystem functioning. One general definition of connectivity is that it is an emergent process arising from a set of spatial interdependencies between individuals or populations, and increasingly realistic representations of connectivity are being sought. Generally, connectivity consists of a structural component, relating to the distribution of suitable and unsuitable habitat, and a functional …

The Motion Of Trees In The Wind: A Data Synthesis, Toby D. Jackson, Sarab Sethi, Ebba Dellwik, Nikolas Angelou, Amanda Bunce, Tim Van Emmerick, Marine Duperat, Jean-Claude Ruel, Axel Wellpott, Brian Kane

Environmental Conservation Faculty Publication Series

Interactions between wind and trees control energy exchanges between the atmosphere and forest canopies. This energy exchange can lead to the widespread damage of trees, and wind is a key disturbance agent in many of the world's forests. However, most research on this topic has focused on conifer plantations, where risk management is economically important, rather than broadleaf forests, which dominate the forest carbon cycle. This study brings together tree motion time-series data to systematically evaluate the factors influencing tree responses to wind loading, including data from both broadleaf and coniferous trees in forests and open environments. We found that …

Hatching Date Influences Winter Habitat Occupancy: Examining Seasonal Interactions Across The Full Annual Cycle In A Migratory Songbird, Michael E. Akresh, David I. King, Peter P. Marra

Environmental Conservation Faculty Publication Series

Birds experience a sequence of critical events during their life cycle, and past events can subsequently determine future performance via carry-over effects. Events during the non-breeding season may influence breeding season phenology or productivity. Less is understood about how events during the breeding season affect individuals subsequently in their life cycle. Using stable carbon isotopes, we examined carry-over effects throughout the annual cycle of prairie warblers (Setophaga discolor), a declining Nearctic-Neotropical migratory passerine bird. In drier winters, juvenile males that hatched earlier at our study site in Massachusetts, USA, occupied wetter, better-quality winter habitat in the Caribbean, as indicated by …

Plant Distribution Data Show Broader Climatic Limits Than Expert-Based Climatic Tolerance Estimates, Caroline A. Curtis, Bethany A. Bradley

Environmental Conservation Faculty Publication Series

Background

Although increasingly sophisticated environmental measures are being applied to species distributions models, the focus remains on using climatic data to provide estimates of habitat suitability. Climatic tolerance estimates based on expert knowledge are available for a wide range of plants via the USDA PLANTS database. We aim to test how climatic tolerance inferred from plant distribution records relates to tolerance estimated by experts. Further, we use this information to identify circumstances when species distributions are more likely to approximate climatic tolerance.

Methods

We compiled expert knowledge estimates of minimum and maximum precipitation and minimum temperature tolerance for over 1800 …

Spatial Capture–Recapture Models Allowing Markovian Transience Or Dispersal, J. Royle, Angela Fuller, Chris Sutherland

Environmental Conservation Faculty Publication Series

Spatial capture–recapture (SCR) models are a relatively recent development in quantitative ecology, and they are becoming widely used to model density in studies of animal populations using camera traps, DNA sampling and other methods which produce spatially explicit individual encounter information. One of the core assumptions of SCR models is that individuals possess home ranges that are spatially stationary during the sampling period. For many species, this assumption is unlikely to be met and, even for species that are typically territorial, individuals may disperse or exhibit transience at some life stages. In this paper we first conduct a simulation study …

Quantifying The Human Influence On Fire Ignition Across The Western Usa, Emily J. Fusco, John T. Abatzoglou, Jennifer K. Balch, John T. Finn, Bethany Bradley

Environmental Conservation Faculty Publication Series

Humans have a profound effect on fire regimes by increasing the frequency of ignitions. Although ignition is an integral component of understanding and predicting fire, to date fire models have not been able to isolate the ignition location, leading to inconsistent use of anthropogenic ignition proxies. Here, we identified fire ignitions from the Moderate Resolution Imaging Spectrometer (MODIS) Burned Area Product (2000–2012) to create the first remotely sensed, consistently derived, and regionally comprehensive fire ignition data set for the western United States. We quantified the spatial relationships between several anthropogenic land-use/disturbance features and ignition for ecoregions within the study area …

Continent-Wide Survey Reveals Massive Decline In African Savannah Elephants, Michael J. Chase, Scott Schlossberg, Curtice R. Griffin, Philippe J.C. Bouché, Sintayehu W. Djene, Paul W. Elkan, Sam Ferreira, Falk Grossman, Edward Mtarima Kohi, Kelly Landen, Patrick Omondi, Alexis Peltier, S.A. Jeanetta Selier, Robert Sutcliffe

Environmental Conservation Faculty Publication Series

African elephants (Loxodonta africana) are imperiled by poaching and habitat loss. Despite global attention to the plight of elephants, their population sizes and trends are uncertain or unknown over much of Africa. To conserve this iconic species, conservationists need timely, accurate data on elephant populations. Here, we report the results of the Great Elephant Census (GEC), the first continent-wide, standardized survey of African savannah elephants. We also provide the first quantitative model of elephant population trends across Africa. We estimated a population of 352,271 savannah elephants on study sites in 18 countries, representing approximately 93% of all savannah …

Spatial Capture–Recapture: A Promising Method For Analyzing Data Collected Using Artificial Cover Objects, Chris Sutherland, David Mun'oz, David Miller, Evan Grant

Environmental Conservation Faculty Publication Series

Spatial capture–recapture (SCR) is a relatively recent development in ecological statistics that provides a spatial context for estimating abundance and space use patterns, and improves inference about absolute population density. SCR has been applied to individual encounter data collected noninvasively using methods such as camera traps, hair snares, and scat surveys. Despite the widespread use of capture based surveys to monitor amphibians and reptiles, there are few applications of SCR in the herpetological literature. We demonstrate the utility of the application of SCR for studies of reptiles and amphibians by analyzing capture–recapture data from Red-Backed Salamanders, Plethodon cinereus, collected using …

Likelihood Analysis Of Spatial Capture-Recapture Models For Stratified Or Class Structured Populations, J. Royle, Chris Sutherland, Angela Fuller, Catherine Sun

Environmental Conservation Faculty Publication Series

We develop a likelihood analysis framework for fitting spatial capture-recapture (SCR) models to data collected on class structured or stratified populations. Our interest is motivated by thenecessity of accommodating the problem of missing observations of individual class membership. This is particularly problematic in SCR data arising from DNA analysis of scat, hair or other material, whichfrequently yields individual identity but fails to identify the sex. Moreover, this can represent a large fraction of the data and, given the typically small sample sizes of many capture-recapture studies based on DNA information, utilization of the data with missing sex information is necessary. …

Modelling Non-Euclideanmovement And Landscape Connectivity In Highly Structured Ecological Networks, Chris Sutherland, Angela Fuller, J. Royle

Environmental Conservation Faculty Publication Series

1. Movement is influenced by landscape structure, configuration and geometry, but measuring distance as perceived by animals poses technical and logistical challenges. Instead, movement is typically measured using Euclidean distance, irrespective of location or landscape structure, or is based on arbitrary cost surfaces. Arecently proposed extension of spatial capture-recapture (SCR)models resolves this issue using spatial encounterhistories of individuals to calculate least-cost paths (ecological distance: Ecology, 94, 2013, 287) thereby relaxingthe Euclidean assumption. We evaluate the consequences of not accounting for movement heterogeneity whenestimating abundance in highly structured landscapes, and demonstrate the value of this approach for estimatingbiologically realistic space-use patterns …

A Demographic, Spatially Explicit Patch Occupancy Model Of Metapopulation Dynamics And Persistence, Chris Sutherland, D. Elston, X. Lambin

Environmental Conservation Faculty Publication Series

Patch occupancy models are extremely important and popular tools forunderstanding the dynamics, and predicting the persistence, of spatially structuredpopulations. Typically this endeavor is facilitated either by models from classic metapopulationtheory focused on spatially explicit, dispersal-driven colonization–extinction dynamicsand generally assuming perfect detection, or by more recent hierarchical site occupancymodels that account for imperfect detection but rarely include spatial effects, such as dispersal,explicitly. Neither approach explicitly considers local demographics in a way that can be usedfor future projections. However, despite being arguably of equal importance, dispersal andconnectivity, local demography, and imperfect detection are rarely modeled explicitly andsimultaneously. Understanding the spatiotemporal occurrence patterns …

Accounting For False Positive Detection Error Induced By Transient Individuals, Chris Sutherland, D Elston, X. Lambin

Environmental Conservation Faculty Publication Series

Context. In metapopulations, colonisation is the result of dispersal from neighbouring occupied patches, typically juveniles dispersing from natal to breeding sites. When occupancy dynamics are dispersal driven, occupancy should refer to the presence of established, breeding populations. The detection of transient individuals at sites that are, by definition, unoccupied (i.e. false positive detections), may result in misleading conclusions about metapopulation dynamics. Until recently, the issue of false positives has been considered negligible and current efforts to account for such error have beenrestricted to the context of species misidentification. However, the detection of transient individuals visiting multiple siteswhile dispersing is a …