Robert J. Fletcher

University of Florida | UF · Department of Wildlife Ecology and Conservation

Invasive exotic species are spreading rapidly throughout the planet. These species can have widespread impacts on biodiversity, yet the ability for native species, particularly long-lived vertebrates, to respond rapidly to invasions remains mostly unknown. Here we provide evidence of rapid morphological change in the endangered snail kite (Rostrham...

Significance Connectivity, or the degree to which individuals can move across landscapes, is essential for species persistence and the maintenance of biodiversity. While connectivity is increasingly understood for some individual species and landscapes, understanding and predicting connectivity for entire communities remains elusive despite its imp...

International demand for wood and other forest products continues to grow rapidly, and uncertainties remain about how animal communities will respond to intensifying resource extraction associated with woody bioenergy production. We examined changes in alpha and beta diversity of bats, bees, birds, and reptiles across wood production landscapes in...

Balancing the competing, and often conflicting, needs of people and wildlife in shared landscapes is a major challenge for conservation science and policy worldwide. Connectivity is critical for wildlife persistence, but dispersing animals may come into conflict with people, leading to severe costs for humans and animals and impeding connectivity....

Habitat loss is often considered the greatest near-term threat to biodiversity, while the impact of habitat fragmentation remains intensely debated. A key issue of this debate centers on the problem of scale-landscape or patch-at which to assess the consequences of fragmentation. Yet patterns are often confounded across scales, and experimental des...

The once vast and interconnected Everglades wetland ecosystem in Florida underwent a 50% reduction in area in the 1900s, resulting in a highly compartmentalized and managed system where ecological restoration is ongoing. Everglade snail kites (Rostrhamus sociabilis plumbeus, hereafter snail kites) are federally endangered wetland specialists with a...

Understanding how species respond to the environment is essential in ecology, evolution, and conservation. Abiotic factors can influence species responses and the multi‐dimensional space of abiotic factors that allows a species to grow represents the environmental niche. While niches are often assumed to be constant and robust, they are most likely...

Many early successional and disturbance-dependent bird species have declined over the past several decades. Cavitynesting birds in early successional forests are vulnerable because they often require specific habitat characteristics and frequent disturbance events. We examined whether stand age (a proxy for forest succession), stand size, and snag...

Consumers, including megaherbivores and fire, are considered important limiting forces for woody plants and canopy closure in African savannas. However, climatic events like drought can also play a significant role in limiting trees and maintaining tree‐grass coexistence in savannas. The extent to which top‐down control (e.g. megaherbivores) and bo...

Changes in global bioenergy consumption have catalyzed the emergence of forest plantations as an important energy alternative. In the southeastern United States, land cover changes caused by increasing demands for pine trees as a bioenergy feedstock incite associated impacts on local ecosystem services (e.g., water yield). However, water yield impa...

Genetic connectivity lies at the heart of evolutionary theory, and landscape genetics has rapidly advanced to understand how gene flow can be impacted by the environment. Isolation by landscape resistance, often inferred through the use of circuit theory, is increasingly identified as being critical for predicting genetic connectivity across comple...

The natal environment can have long-term fitness consequences for individuals, particularly via 'silver spoon' or 'environmental matching' effects. Invasive species could alter natal effects on native species by changing species interactions, but this potential remains unknown. Using 17 years of data on 2588 individuals across the entire US breedin...

Although matrix improvement in fragmented landscapes is a promising conservation measure, matrix permeability (willingness of an organism to enter the matrix) and movement survival in the matrix are usually aggregated. Consequently, it is unknown which matrix property needs to be improved. It also remains unclear whether matrix upgrading from dispe...

1. Understanding animal movement often relies upon telemetry and biologging devices. These data are frequently used to estimate latent behavioral states to help understand why animals move across the landscape. While there are a variety of methods that make behavioral inferences from biotelemetry data, some features of these methods (e.g., analysis...

As Amazon deforestation rates reach the highest levels observed in the past decade, it is extremely important to direct conservation efforts to regions containing preserved forests with a high risk of deforestation. This requires forecasting deforestation, a complex endeavor due to the interplay of multiple socioeconomic and environmental factors a...

Increased agricultural intensification and extensive woody plant encroachment are having widespread effects on the functioning of grass-dominated systems at multiple spatial scales. Yet there is little understanding of how the provisioning of biodiversity-based ecosystem services might be altered by these ongoing changes. One fundamental ecosystem...

In savannas across the planet, encroaching woody plants are altering ecosystem functions and reshaping communities. Seed predation by rodents may serve to slow the encroachment of woody plants in grasslands and savannas. Our goals for this study were to determine if rodents in an African savanna selectively removed seeds of an encroaching plant and...

ContextUnderstanding the relative contributions of spatial and environmental processes on community assembly is a central question in ecology. Despite this long-standing interest, our understanding of how landscape structure may drive spatial processes of community assembly remains poorly understood in part because of the challenge of tracking comm...

Agricultural intensification is a threat to terrestrial ecosystems around the world. Agricultural areas, especially monocultures, create homogenous landscapes for wildlife. However, certain crops, such as sugarcane, are harvested in phases, creating a mosaic of fields in different stages of growth. We investigated changes in avian communities acros...

Small changes in the environment can have large impacts, leading to ‘tipping points’ or ‘threshold’ effects on populations. Identifying such effects can provide practitioners benchmarks to both minimize negative impacts and foster positive benefits for populations. Nonetheless, identifying thresholds can be challenging as they can vary spatially, t...

Bioenergy produced from woody biomass in managed forest systems represents a substantial portion of the global supply of renewable energy. As societies transition to renewable energy and demand for wood-based bioenergy increases, timber-producing forests and other agricultural and marginal lands may transition to bioenergy management regimes. Limit...

1. Understanding animal movement often relies upon telemetry and biologging devices. These data are frequently used to estimate latent behavioral states to help understand why animals move across the landscape. While there are a variety of methods that make behavioral inferences from biotelemetry data, some features of these methods (e.g., analysis...

Conservation and management increasingly focus on connectivity, because connectivity driven by variation in immigration rates across landscapes is thought to be crucial for maintaining local population and metapopulation persistence. Yet, efforts to quantify the relative role of immigration on population growth across the entire range of species an...

Landscape connectivity is increasingly promoted as a conservation tool to combat the negative effects of habitat loss, fragmentation, and climate change. Given its importance as a key conservation strategy, connectivity science is a rapidly growing discipline. However, most landscape connectivity models consider connectivity for only a single snaps...

Land‐cover and land‐use change are major drivers of global biodiversity loss. Savannas are experiencing shrub encroachment and land‐use changes that affect animal communities, yet how the effects of shrub encroachment vary with land use remains unclear. We also need to determine which species traits explain the effects of shrub encroachment and lan...

Human demand for food, fiber, and space is accelerating the rate of change of land cover and land use. Much of the world now consists of a matrix of natural forests, managed forests, agricultural cropland, and urbanized plots. Expansion of domestic energy production efforts in the USA is one driver predicted to influence future land‐use and land ma...

Maintaining the ability of organisms to move between suitable patches of habitat despite ongoing habitat loss is essential to conserving biodiversity. Quantifying connectivity has therefore become a central focus of conservation planning. A large number of metrics have been developed to estimate potential connectivity based on habitat configuration...

Central-place foragers can be constrained by the distance between habitats. When an organism relies on a central place for thermal refuge, the distance to food resources can potentially constrain foraging behavior. We investigated the effect of distance between thermal refuges and forage patches of the cold-intolerant marine mammal, the Florida man...

1.Cultivation of bioenergy feedstocks is a growing land‐use worldwide, yet we have a poor understanding of how bioenergy crop management practices affect biodiversity. This knowledge gap is particularly acute for candidate cellulosic bioenergy feedstocks, such as tree plantations, and for organisms that provide important ecosystem services, such as...

Quantifying landscape connectivity is fundamental to better understand and predict how populations respond to environmental change. Currently, popular methods to quantify landscape connectivity emphasize how landscape features provide resistance to movement. While many tools are available to quantify landscape resistance, these do not discern betwe...

Some of the world’s deadliest diseases and greatest public health challenges are zoonoses from wildlife, such as Ebola (Ebolavirus). Due to the increasing number of cases in recent years, it has been widely hypothesized that increasing human population densities and anthropogenic disturbance largely explain outbreaks of Ebola virus disease in human...

Understanding how the world's flora and fauna will respond to bioenergy expansion is critical. This issue is particularly pronounced considering bioenergy's potential role as a driver of land-use change, the variety of production crops being considered and currently used for biomass, and the diversity of ecosystems that can potentially supply land...

Vulnerability to habitat fragmentation Habitat fragmentation caused by human activities has consequences for the distribution and movement of organisms. Betts et al. present a global analysis of how exposure to habitat fragmentation affects the composition of ecological communities (see the Perspective by Hargreaves). In a dataset consisting of 448...

For species with geographically restricted distributions, the impacts of habitat loss and fragmentation on long-term persistence may be particularly pronounced. We examined the genetic structure of Panama City crayfish (PCC), Procambarus econfinae, whose historical distribution is limited to an area approximately 145 km2, largely within the limits...

Habitat connectivity enhances diversity Fragmentation of ecosystems leads to loss of biodiversity in the remaining habitat patches, but retaining connecting corridors can reduce these losses. Using long-term data from a large, replicated experiment, Damschen et al. show quantitatively how these losses are reduced. In their pine savanna system, corr...

Selective logging is the primary cause of tropical forest degradation and is rapidly expanding worldwide. While the impacts of logging on species diversity and distributions are well understood, little is known about the effects of logging on animal behaviours central to individual fitness and population persistence. The song rate of breeding songb...

Context Land-use change is a key driver of pollinator declines worldwide. Plantation forests are a major land use worldwide and are likely to expand substantially in the near term, especially with projected cellulosic biofuel production. But little is known about the potential local and landscape-scale impacts of plantation forestry on bees, the mo...

Connectivity is central to ecology and evolution as it focuses on the movement of individuals or genes across landscapes. Genetic connectivity approaches aim to understand gene flow but often estimate it indirectly based on metrics of genetic differentiation, which can also be affected by other evolutionary forces such as genetic drift. Gene flow a...

Payments for Ecosystem Services (PES) programs are increasingly emphasized to address challenges of conserving forests. However, concerns remain regarding the ability of PES programs to ensure long-term conservation of threatened lands. Evaluation of large-scale PES programs, including the spatial and temporal patterns of enrollment, is scarce, esp...

Understanding and accurately modeling species distributions lies at the heart of many problems in ecology, evolution, and conservation. Multiple sources of data are increasingly available for modeling species distributions, such as data from citizen science programs, atlases, museums, and planned surveys. Yet reliably combining data sources can be...

1.Better understanding human‐wildlife interactions and their links with management can help improve the design of wildlife protection zones. One example is the problem of wildlife collisions with vehicles or human‐built structures (e.g. power lines, wind farms). In fact, collisions between marine wildlife and watercraft are among the major threats...

Movement is important for ecological and evolutionary theory as well as connectivity conservation, which is increasingly critical for species responding to environmental change. Key ecological and evolutionary outcomes of movement, such as population growth and gene flow, require effective dispersal: movement that is followed by successful reproduc...

There is an ongoing need to integrate agricultural production with wildlife conservation to maintain biodiversity, especially in developing countries. The landscape heterogeneity hypothesis identifies a potential means for promoting biodiversity in agricultural landscapes by emphasizing that increasing heterogeneity can increase biodiversity. Howev...

Habitat loss is often considered the greatest near‐term threat to biodiversity. Yet the impact of habitat fragmentation, or the change in habitat configuration for a given amount of habitat loss, has been intensely debated. We isolated effects of habitat loss from fragmentation on the demography, movement, and abundance of wild populations of a spe...

Understanding how species composition varies across space and time is fundamental to ecology. While multiple methods having been created to characterize this variation through the identification of groups of species that tend to co-occur, most of these methods unfortunately are not able to represent gradual variation in species composition. The Lat...

Tropical forest degradation is a global environmental issue. In degraded forests, seedling recruitment of canopy trees is vital for forest regeneration and recovery. We investigated how selective logging, a pervasive driver of tropical forest degradation, impacts canopy tree seedling recruitment, focusing on an endemic dipterocarp Dryobalanops lanc...

Genetic structure and genetic diversity are key population characteristics that can inform conservation decisions, such as delineating management units or assessing potential risks for inbreeding depression. Evidence of genetic structuring or low genetic diversity in the critically endangered snail kite (Rostrhamus sociabilis plumbeus) would have i...

Context The landscape heterogeneity hypothesis states that increased heterogeneity in agricultural landscapes will promote biodiversity. However, this hypothesis does not detail which components of landscape heterogeneity (compositional or configurational) most affect biodiversity and how these compare to the effects of surrounding agricultural lan...

Habitat selection, resource selection, and space use are related concepts that lie at the foundation of much research and several applications in wildlife ecology and it has long been emphasized in ecological theory. It is also highly relevant for spatial ecology because habitat selection is frequently viewed to operate at different spatial and tem...

How space directly and indirectly affects biodiversity and ecosystem functioning is the focus of several subdisciplines in the life sciences. All of these subdisciplines share concepts and analytical methods that stem from the field of spatial ecology. Spatial ecology focuses on the study and modeling of the role(s) of space on ecological processes...

One common type of data used in spatial ecology and conservation is point data. Point data, or data that describe distinct locations in space, might reflect the locations of individual trees, nests of birds, or patchy disturbances. Often the focus of point pattern analysis is on quantifying spatial dispersion, determining if and how dispersion vari...

The detection, characterization, and significance testing of spatial pattern is the first step to understand spatial ecological data and the processes that generated them. Spatial dependence commonly occurs in ecological data and it is often argued that failure to account for spatial dependence can impact inferences in ecology and guidance for cons...

The presence of spatial dependence can impair the statistical inference and subsequent ecological interpretation of the pattern(s) observed. It is important to understand how statistical biases due to spatially structured data can affect a wide array of ecological questions ranging from species–environment relationships to predicting the spread of...

This book provides a foundation for modern applied ecology. Much of current ecology research and conservation addresses problems across landscapes and regions, focusing on spatial patterns and processes. This book is aimed at teaching fundamental concepts and focuses on learning-by-doing through the use of examples with the software R. It is intend...

Understanding spatial and temporal variation in land use and land cover is a topic that bridges a variety of disciplines such as ecology, geography, sociology, and economics. Land-use and land-cover change has major impacts on biodiversity and ecosystem services. Our goals are to introduce key concepts regarding land-use and land-cover change and p...

To understand the importance of space, the field of spatial ecology has emerged as a central focus for many topics in ecology and conservation. Looking back at the last two decades, it is impressive just how much the problem of space has intrigued the minds of ecologists and conservation biologists. This focus has arisen from both theoretical and a...

The importance of space for ecology and conservation relies on the importance of connectivity. It is well known that connectivity can influence populations and communities through a variety of mechanisms, and promoting connectivity is frequently championed as a way to mitigate negative effects of environmental change. Here, we provide an overview o...

Over the past several decades, the role of space in population dynamics and trends has been illuminated, and spatially structured population dynamics have been emphasized in conservation and management strategies. We use the term spatially structured population as a broad umbrella term for a population that includes some amount of spatial heterogen...

All topics in ecology and conservation play out in space and time at multiple scales. These scales describe the spatiotemporal dimensions of patterns or processes. By understanding and quantifying spatial scale, it can profoundly influence our understanding of ecological patterns and processes, and it can alter conservation decisions. Scale has two...

Biodiversity is the variety of life. It is fundamental to all aspects of ecology and conservation biology. Biodiversity can be measured at different levels of organization and at different scales. Here, we provide an overview of how space influences biological communities, why space is important for biodiversity conservation, and we illustrate some...

Predictive models of species distributions are increasingly used in both basic and applied ecology to map species distributions and predict the effects of environmental change. Here, we describe the key concepts relevant to predicting species distributions (focusing on the use of niche theory), the types of data typically used, some common modeling...

Across the planet, grass-dominated biomes are experiencing shrub encroachment driven by atmospheric CO2 enrichment and land-use change. By altering resource structure and availability, shrub encroachment may have important impacts on vertebrate communities. We sought to determine the magnitude and variability of these effects across climatic gradie...

ContextLandscape complementation, or how landscapes that contain two or more non-substitutable and spatially separated resources facilitate resource use, is critical for many populations. Implicit to the problem of landscape complementation is the movement of individuals to access multiple resources. Conventional measures of complementation, such a...

This paper studies an interdiction problem in which two agents with opposed interests, a defender and an attacker, interact in a system governed by an absorbing discrete-time Markov chain. The defender protects a subset of transient states, whereas the attacker targets a subset of the unprotected states. By changing some of the transition probabili...

Time series analysis is an essential method for decomposing the influences of density and exogenous factors such as weather and climate on population regulation. However, there has been little work focused on understanding how well commonly collected data can reconstruct the effects of environmental factors on population dynamics. We show that anal...

ContextAsymmetric movements, in which the probability of moving from patch i to patch j is not necessarily the same as moving in the opposite direction, may be the rule more than the exception in nature where organisms move through spatially heterogeneous environments. Empirical tests of dispersal asymmetries are rare with even fewer tests of the m...

Concerns over energy demands and climate change has led the United States to set ambitious targets for bioenergy production in the coming decades. The southeastern U.S. has had a recent increase in biomass woody pellet production and is projected to produce a large portion of the nation's cellulosic biofuels. We conducted a large-scale, systematic...