Habitat‐selection analyses allow researchers to link animals to their environment via habitat‐selection or step‐selection functions, and are commonly used to address questions related to wildlife ...management and conservation efforts. Habitat‐selection analyses that incorporate movement characteristics, referred to as integrated step‐selection analyses, are particularly appealing because they allow modelling of both movement and habitat‐selection processes.
Despite their popularity, many users struggle with interpreting parameters in habitat‐selection and step‐selection functions. Integrated step‐selection analyses also require several additional steps to translate model parameters into a full‐fledged movement model, and the mathematics supporting this approach can be challenging for many to understand.
Using simple examples, we demonstrate how weighted distribution theory and the inhomogeneous Poisson point process can facilitate parameter interpretation in habitat‐selection analyses. Furthermore, we provide a ‘how to’ guide illustrating the steps required to implement integrated step‐selection analyses using the amt package
By providing clear examples with open‐source code, we hope to make habitat‐selection analyses more understandable and accessible to end users.
Habitat‐selection analyses allow researchers to link animals to their environment in support of wildlife management and conservation efforts. We provide a ‘how to' guide for correctly interpreting parameters in habitat‐ and step‐selection functions and for implementing integrated step‐selection analyses using the amt package for program R.
Habitat‐selection analyses are often used to link environmental covariates, measured within some spatial domain of assumed availability, to animal location data that are assumed to be independent. ...Step‐selection functions (SSFs) relax this independence assumption, by using a conditional model that explicitly acknowledges the spatiotemporal dynamics of the availability domain and hence the temporal dependence among successive locations. However, it is not clear how to produce an SSF‐based map of the expected utilization distribution. Here, we used SSFs to analyze virtual animal movement data generated at a fine spatiotemporal scale and then rarefied to emulate realistic telemetry data. We then compared two different approaches for generating maps from the estimated regression coefficients. First, we considered a naïve approach that used the coefficients as if they were obtained by fitting an unconditional model. Second, we explored a simulation‐based approach, where maps were generated using stochastic simulations of the parameterized step‐selection process. We found that the simulation‐based approach always outperformed the naïve mapping approach and that the latter overestimated home‐range size and underestimated local space‐use variability. Differences between the approaches were greatest for complex landscapes and high sampling rates, suggesting that the simulation‐based approach, despite its added complexity, is likely to offer significant advantages when applying SSFs to real data.
In recent years the American public has witnessed several hard-fought battles over nominees to the U.S. Supreme Court. In these heated confirmation fights, candidates' legal and political ...philosophies have been subject to intense scrutiny and debate.Citizens, Courts, and Confirmationsexamines one such fight--over the nomination of Samuel Alito--to discover how and why people formed opinions about the nominee, and to determine how the confirmation process shaped perceptions of the Supreme Court's legitimacy.
Drawing on a nationally representative survey, James Gibson and Gregory Caldeira use the Alito confirmation fight as a window into public attitudes about the nation's highest court. They find that Americans know far more about the Supreme Court than many realize, that the Court enjoys a great deal of legitimacy among the American people, that attitudes toward the Court as an institution generally do not suffer from partisan or ideological polarization, and that public knowledge enhances the legitimacy accorded the Court. Yet the authors demonstrate that partisan and ideological infighting that treats the Court as just another political institution undermines the considerable public support the institution currently enjoys, and that politicized confirmation battles pose a grave threat to the basic legitimacy of the Supreme Court.
Popular frameworks for studying habitat selection include resource‐selection functions (RSFs) and step‐selection functions (SSFs), estimated using logistic and conditional logistic regression, ...respectively. Both frameworks compare environmental covariates associated with locations animals visit with environmental covariates at a set of locations assumed available to the animals. Conceptually, slopes that vary by individual, that is, random coefficient models, could be used to accommodate inter‐individual heterogeneity with either approach. While fitting such models for RSFs is possible with standard software for generalized linear mixed‐effects models (GLMMs), straightforward and efficient one‐step procedures for fitting SSFs with random coefficients are currently lacking.
To close this gap, we take advantage of the fact that the conditional logistic regression model (i.e. the SSF) is likelihood‐equivalent to a Poisson model with stratum‐specific fixed intercepts. By interpreting the intercepts as a random effect with a large (fixed) variance, inference for random‐slope models becomes feasible with standard Bayesian techniques, or with frequentist methods that allow one to fix the variance of a random effect. We compare this approach to other commonly applied alternatives, including models without random slopes and mixed conditional regression models fit using a two‐step algorithm.
Using data from mountain goats (Oreamnos americanus) and Eurasian otters (Lutra lutra), we illustrate that our models lead to valid and feasible inference. In addition, we conduct a simulation study to compare different estimation approaches for SSFs and to demonstrate the importance of including individual‐specific slopes when estimating individual‐ and population‐level habitat‐selection parameters.
By providing coded examples using integrated nested Laplace approximations (INLA) and Template Model Builder (TMB) for Bayesian and frequentist analysis via the R packages R‐INLA and glmmTMB, we hope to make efficient estimation of RSFs and SSFs with random effects accessible to anyone in the field. SSFs with individual‐specific coefficients are particularly attractive since they can provide insights into movement and habitat‐selection processes at fine‐spatial and temporal scales, but these models had previously been very challenging to fit.
The authors provide a coherent framework for fitting resource‐selection functions (RSFs) and step‐selection functions (SSFs) with random effects. To allow fitting of SSFs, the authors reformulate the conditional logistic regression model as a (likelihood‐equivalent) Poisson model, where stratum‐specific intercepts are included as a random effect with a fixed large prior variance.
In management, decisions are expected to be based on rational analytics rather than intuition. But intuition, as a human evolutionary achievement, offers wisdom that, despite all the advances in ...rational analytics and AI, should be used constructively when recruiting and winning personnel. Integrating these inner experiential competencies with rational-analytical procedures leads to smart recruiting decisions.
Advances in tracking technology have led to an exponential increase in animal location data, greatly enhancing our ability to address interesting questions in movement ecology, but also presenting ...new challenges related to data management and analysis. Step‐selection functions (SSFs) are commonly used to link environmental covariates to animal location data collected at fine temporal resolution. SSFs are estimated by comparing observed steps connecting successive animal locations to random steps, using a likelihood equivalent of a Cox proportional hazards model. By using common statistical distributions to model step length and turn angle distributions, and including habitat‐ and movement‐related covariates (functions of distances between points, angular deviations), it is possible to make inference regarding habitat selection and movement processes or to control one process while investigating the other. The fitted model can also be used to estimate utilization distributions and mechanistic home ranges. Here, we present the R package amt (animal movement tools) that allows users to fit SSFs to data and to simulate space use of animals from fitted models. The amt package also provides tools for managing telemetry data. Using fisher (Pekania pennanti) data as a case study, we illustrate a four‐step approach to the analysis of animal movement data, consisting of data management, exploratory data analysis, fitting of models, and simulating from fitted models.
New tracking technologies allow users to collect large amount of data and address entirely new questions. The amt (animal movement tools) R package provides tools to manage telemetry data and to fit step‐selection functions and resource‐selection functions.
No other scientific theory has had as tremendous an impact on our understanding of the world as Darwin's theory as outlined in his Origin of Species, yet from the very beginning the theory has been ...subject to controversy. The Evolution of Darwinism, first published in 2004, focuses on three issues of debate - the nature of selection, the nature and scope of adaptation, and the question of evolutionary progress. It traces the varying interpretations to which these issues were subjected from the beginning and the fierce contemporary debates that still rage on and explores their implications for the greatest questions of all: Where we come from, who we are and where we might be heading. Written in a clear and non-technical style, this book will be of use as a textbook for students in the philosophy of science who need to become familiar with the background to the debates about evolution.
A century of selection Ryan, Ann Marie; Ployhart, Robert E
Annual review of psychology,
01/2014, Letnik:
65
Journal Article
Recenzirano
Odprti dostop
Over 100 years of psychological research on employee selection has yielded many advances, but the field continues to tackle controversies and challenging problems, revisit once-settled topics, and ...expand its borders. This review discusses recent advances in designing, implementing, and evaluating selection systems. Key trends such as expanding the criterion space, improving situational judgment tests, and tackling socially desirable responding are discussed. Particular attention is paid to the ways in which technology has substantially altered the selection research and practice landscape. Other areas where practice lacks a research base are noted, and directions for future research are discussed.
A study of more than 650 toddlers found that two polyunsaturated fatty acids were associated with fewer cases of allergic rhinitis (hay fever) in children who had been exposed prenatally to higher ...levels of PM2.5.A study of more than 650 toddlers found that two polyunsaturated fatty acids were associated with fewer cases of allergic rhinitis (hay fever) in children who had been exposed prenatally to higher levels of PM2.5.
Most tools that measure environmental health literacy are broad in nature. Researchers have now developed a tool specific to phthalate awareness and behaviors as they relate to reproductive ...health.Most tools that measure environmental health literacy are broad in nature. Researchers have now developed a tool specific to phthalate awareness and behaviors as they relate to reproductive health.
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