Aim: To evaluate how environment and evolutionary history interact to influence
global patterns of mammal trait diversity (a combination of 14 morphological and
life-history traits).
Location: The global terrestrial environment.
Taxon: Terrestrial mammals.
Methods: We calculated patterns of spatial turnover for mammalian traits and phylogenetic
lineages using the mean nearest taxon distance. We then used a variance
partitioning approach to establish the relative contribution of trait conservatism,
ecological adaptation and clade specific ecological preferences on global trait
turnover.
Results: We provide a global scale analysis of trait turnover across mammalian terrestrial
assemblages, which demonstrates that phylogenetic turnover by itself does
not predict trait turnover better than random expectations. Conversely, trait turnover
is consistently more strongly associated with environmental variation than
predicted by our null models. The influence of clade-specific ecological preferences,
reflected by the shared component of phylogenetic turnover and environmental
variation, was considerably higher than expectations. Although global patterns of
trait turnover are dependent on the trait under consideration, there is a consistent
association between trait turnover and environmental predictive variables, regardless
of the trait considered.
Main conclusions: Our results suggest that changes in phylogenetic composition
are not always coupled with changes in trait composition on a global scale and that
environmental conditions are strongly associated with patterns of trait composition
across species assemblages, both within and across phylogenetic clades.
File: Holt2018_jbi.13091.pdf
This is a publication uploaded with a php script
Global variation in species richness is widely recognized, but the explanation
for what drives it continues to be debated. Previous efforts have focused on a
subset of potential drivers, including evolutionary rate, evolutionary time
(maximum clade age of species restricted to a region), dispersal (migration
from one region to another), ecological factors and climatic stability. However,
no study has evaluated these competing hypotheses simultaneously at a broad
spatial scale. Here, we examine their relative contribution in determining the
richness of the most comprehensive dataset of tetrapods to our knowledge
(84% of the described species), distinguishing between the direct influences of
evolutionary rate, evolutionary time and dispersal, and the indirect influences
of ecological factors and climatic stability through their effect on direct factors.
We found that evolutionary time exerted a primary influence on species richness,
with evolutionary rate being of secondary importance. By contrast,
dispersal did not significantly affect richness patterns. Ecological and climatic
stability factors influenced species richness indirectly by modifying evolutionary
time (i.e. persistence time) and rate. Overall, our findings suggest that
global heterogeneity in tetrapod richness is explained primarily by the
length of time species have had to diversify.
File: Marin-et-al.-2018.pdf
This is a publication uploaded with a php script
When political regimes fall, economic conditions change and wildlife protection can be undermined. Eastern
European countries experienced turmoil following the collapse of socialism in the early 1990s, raising the
question of how wildlife was affected. We show that the aftermath of the collapse changed the population
growth rates of various wildlife taxa. We analyzed populations of moose (Alces alces), wild boar (Sus scrofa),
red deer (Cervus elaphus), roe deer (Capreolus capreolus), brown bear (Ursus arctos), Eurasian lynx (Lynx
lynx), and gray wolf (Canis lupus) in nine countries. Population growth rates changed in 32 out of 49 time
series. In the countries that reformed slowly, many species exhibited rapid population declines, and
population
growth rates changed in 83% of the time series. In contrast, in countries with fast post-socialism
reforms, many populations increased rapidly, and growth rates changed in only 48% of time series. Our
results suggest that the direction and frequency of the changes were associated with socioeconomic
conditions,
and that wildlife populations can be greatly affected by socioeconomic upheavals.
File: Bragina2018_WildlifePop_Frontiers.pdf
This is a publication uploaded with a php script
Interactions between multiple anthropogenic environmental changes can
drive non-additive effects in ecological systems, and the non-additive
effects can in turn be amplified or dampened by spatial covariation
among environmental changes. We investigated the combined effects of
night-time warming and light pollution on pea aphids and two predatory
ladybeetle species. As expected, neither night-time warming nor light pollution
changed the suppression of aphids by the ladybeetle species that
forages effectively in darkness. However, for the more-visual predator,
warming and light had non-additive effects in which together they
caused much lower aphid abundances. These results are particularly relevant
for agriculture near urban areas that experience both light
pollution and warming from urban heat islands. Because warming and
light pollution can have non-additive effects, predicting their possible
combined consequences over broad spatial scales requires knowing how
they co-occur. We found that night-time temperature change since 1949
covaried positively with light pollution, which has the potential to increase
their non-additive effects on pea aphid control by 70% in US alfalfa. Our
results highlight the importance of non-additive effects of multiple
environmental factors on species and food webs, especially when these
factors co-occur.
File: Miller2017_LightPollution_ProcB.pdf
This is a publication uploaded with a php script
Identifying which species are at greatest risk, what makes them vulnerable, and where they
are distributed are central goals for conservation science. While knowledge of which factors
influence extinction risk is increasingly available for some taxonomic groups, a deeper
understanding of extinction correlates and the geography of risk remains lacking. Here, we
develop a predictive random forest model using both geospatial and mammalian species'
trait data to uncover the statistical and geographic distributions of extinction correlates. We
also explore how this geography of risk may change under a rapidly warming climate. We
found distinctive macroecological relationships between species-level risk and extinction
correlates, including the intrinsic biological traits of geographic range size, body size and
taxonomy, and extrinsic geographic settings such as seasonality, habitat type, land use and
human population density. Each extinction correlate exhibited ranges of values that were
especially associated with risk, and the importance of different risk factors was not geographically
uniform across the globe. We also found that about 10% of mammals not currently
recognized as at-risk have biological traits and occur in environments that predispose
them towards extinction. Southeast Asia had the most actually and potentially threatened
species, underscoring the urgent need for conservation in this region. Additionally, nearly
40% of currently threatened species were predicted to experience rapid climate change at
0.5 km/year or more. Biological and environmental correlates of mammalian extinction risk
exhibit distinct statistical and geographic distributions. These results provide insight into
species-level patterns and processes underlying geographic variation in extinction risk.
They also offer guidance for future conservation research focused on specific geographic
regions, or evaluating the degree to which species-level patterns mirror spatial variation in
the pressures faced by populations within the ranges of individual species. The added
impacts from climate change may increase the susceptibility of at-risk species to extinction
and expand the regions where mammals are most vulnerable globally.
File: Davidson2017_MammalExtinct_Plos1.pdf
This is a publication uploaded with a php script
Conservation priorities that are based on species distribution,
endemism, and vulnerability may underrepresent biologically
unique species as well as their functional roles and evolutionary
histories. To ensure that priorities are biologically comprehensive,
multiple dimensions of diversity must be considered. Further,
understanding how the different dimensions relate to one another
spatially is important for conservation prioritization, but the
relationship remains poorly understood. Here, we use spatial
conservation planning to (i) identify and compare priority regions
for global mammal conservation across three key dimensions of
biodiversity—taxonomic, phylogenetic, and traits—and (ii) determine
the overlap of these regions with the locations of threatened
species and existing protected areas. We show that priority areas
for mammal conservation exhibit low overlap across the three
dimensions, highlighting the need for an integrative approach
for biodiversity conservation. Additionally, currently protected
areas poorly represent the three dimensions of mammalian biodiversity.
We identify areas of high conservation priority among
and across the dimensions that should receive special attention
for expanding the global protected area network. These highpriority
areas, combined with areas of high priority for other taxonomic
groups and with social, economic, and political considerations,
provide a biological foundation for future conservation
planning efforts.
File: Brum2017_mammals_PNAS.pdf
This is a publication uploaded with a php script
Many systems and processes in ecology cannot be experimentally controlled, either because the temporal and spatial scales are
too broad, or because it would be unethical. Examples include large wildfires, alternative conservation strategies, removal of top
predators, or the introduction of invasive species. Unfortunately, many of these phenomena also do not occur randomly in time or
space, and this can lead to different biases (selection bias, unobserved variable bias) in statistical analyses. Economics has evolved
largely without experiments, and developed statistical approaches to study “quasi-experiments”, i.e., situations were changes
in time or space reveal relationships even in the absence of a controlled experiment. The goal of our paper was to compare and
evaluate four quasi-experimental statistical approaches commonly used in economics, (1) matching, (2) regression discontinuity
design, (3) difference-in-differences models, and (4) instrumental variables, in terms of their relevance for ecological research.
We contrast the strengths and weaknesses of each approach and provide a detailed tutorial to demonstrate these approaches. We
suggest that quasi-experimental methods offer great potential for investigating many phenomena and processes in ecological
and coupled human-natural systems. Furthermore, quasi-experimental methods are common in environmental policy research
and policy recommendations by ecologists may be more valuable when based on these methods.
File: Butsic2017_Quasi_BAE.pdf
This is a publication uploaded with a php script
Aim: Examining the biogeography of body size is crucial for understanding how animal communities
are assembled and maintained. In tetrapods, body size varies predictably with temperature,
moisture, productivity seasonality and topographical complexity. Although millennial-scale human
pressures are known to have led to the extinction of primarily large-bodied tetrapods, human pressure
history is often ignored in studies of body size that focus on extant species. Here, we analyse
11,377 tetrapod species of the Western Hemisphere to test whether millennial-scale human pressures
have left an imprint on contemporary body mass distributions throughout the tetrapod
clade.
Location: Western Hemisphere.
Time period: Contemporary.
Major taxa studied: Tetrapods (birds, mammals, amphibians and reptiles).
Methods: We mapped the distribution of assemblage-level median tetrapod body mass at a resolution
of 110 km across the Western Hemisphere. We then generated multivariate models of
median body mass as a function of temperature, moisture, productivity seasonality and topographical
complexity, as well as two variables capturing the history of human population density and
human-induced land conversion over the past 12,000 years. We controlled for both spatial and
phylogenetic autocorrelation effects on body mass–environment relationships.
Results: Human pressures explain a small but significant portion of geographical variation in
median body mass that cannot be explained by ecological constraints alone. Overall, the median
body mass of tetrapod assemblages is lower than expected in areas with a longer history of high
human population density and land conversion, but there are important differences among tetrapod
classes.
Main conclusions: At this broad scale, the effect of human pressure history on tetrapod body
mass is low relative to that of ecology. However, ignoring spatial variation in the history of human
pressure is likely to lead to bias in studies of the present-day functional composition of tetrapod
assemblages, at least in areas that have long been influenced by humans.
File: Rapacciuolo_et_al-2017-Global_Ecology_and_Biogeography.pdf
This is a publication uploaded with a php script
This is a publication uploaded with a php script
Satellite telemetry is a powerful tool for monitoring animal movements, and Argos transmitters have been widely used. Unfortunately, only few studies have systematically evaluated the performance of Argos satellite collars for wildlife monitoring. We tested Argos satellite telemetry transmitters at two power levels in Southern Russia (five transmitters at 0.5 W and three at 1 W). Performance metrics were derived from the number and accuracy of location estimates and the number of days on which collars transmitted or failed to transmit data. Our results suggest that the performance of Argos collars in our study region was poor. At the power level of 0.5 W, 55% of the sessions resulted in at least one transmission, but only 21% provided a location estimate. The percentage of successful sessions did not increase much after setting the power level to 1.0 W (63%), but the increase in the number of location estimates was considerable (54%). At either power level, the majority of the location estimates were in the low quality classes though (80% nonstandard locations with 0.5 Wand 45% with 1 W). Positional accuracies were 0.5, 0.7, 1.5, and 4.6 km for location classes 3, 2, 1, and 0, respectively. For nonstandard location classes A and B, positional accuracies were 2.1 and 18.3 km. Careful testing of transmitters is recommended before deployment, as the location of the study area can seriously affect performance.
File: Dubinin2010_Article_PerformanceAndAccuracyOfArgosT.pdf
This is a publication uploaded with a php script
