Biology subjects

Gerber, B. D.

Publications and source records attributed to Gerber, B. D..

3 recordsLinked to original sources

bioRxiv2023

A model-based hypothesis framework to define and estimate the diel niche via the 'Diel.Niche' R package

O_LIHow animals use the diel period (24-hour light-dark cycle) is of fundamental importance to understand their niche. While ecological and evolutionary literature abound with discussion of diel phenotypes (e.g., diurnal, nocturnal, crepuscular, cathemeral), they lack clear and explicit quantitative definitions. As such, inference can be confounded when evaluating hypotheses of animal diel niche switching or plasticity across studies because researchers may be operating under different definitions of diel phenotypes. C_LIO_LIWe propose quantitative definitions of diel phenotypes using four alternative hypotheses sets (Maximizing, Traditional, General, and Selection) aimed at achieving different objectives. Each hypothesis set is composed of mutually exclusive hypotheses defined based on the activity probabilities in the three fundamental periods of light availability (twilight, daytime, and nighttime). C_LIO_LIWe develop a Bayesian modeling framework that compares diel phenotype hypotheses using Bayes factors and estimates model parameters using a multinomial model with linear inequality constraints. Model comparison, parameter estimation, and visualizing results can be done in the Diel.Niche R package. A simplified R Shiny web application is also available. C_LIO_LIWe provide extensive simulation results to guide researchers on the power to discriminate among hypotheses for a range of sample sizes (10 to 1280). We also work through several examples of using data to make inferences on diel activity, and include online vignettes on how to use the Diel.Niche package. We demonstrate how our modeling framework complements analyses that are commonly used to investigate diel activity, such as circular kernel density estimators. C_LIO_LIOur aim is to encourage standardization of the language of diel activity and bridge conceptual frameworks and hypotheses in diel research with data and models. Lastly, we hope more research focuses on the ecological and conservation importance of understanding how animals use diel time. C_LI

animal behavior and cognition↗

bioRxiv2020

Sex-segregated range use by black-and-white ruffed lemurs (Varecia variegata) in Ranomafana National Park, Madagascar.

Ranging behavior is one important strategy by which nonhuman primates obtain access to resources critical to their biological maintenance and reproductive success. As most primates live in permanent social groups, their members must balance the benefits of group living with the costs of intragroup competition for resources. However, some taxa live in more spatiotemporally flexible social groups, whose members modify patterns of association and range use as a method to mitigate these costs. Here, we describe the range use of black-and-white ruffed lemurs (Varecia variegata) at Mangevo, an undisturbed primary rainforest site in Ranomafana National Park, Madagascar and characterize sex-differences in annual home range area, overlap, and daily distances traveled. Moreover, we characterized seasonal variability in range use and ask whether ranging behaviors can be explained by either climatic or reproductive seasonality. We found that females used significantly larger home ranges than males, though sexes shared equal and moderate levels of home range overlap. Overall, range use did not vary across seasons; though within sexes, male range use varied significantly with climatic variation. Moreover, daily path length was best predicted by day length, female reproductive state, and sex. While the patterns of range use and spatial association presented here share some similarities with bisexually bonded community models described for chimpanzees, we argue that ruffed lemurs represent yet another community model wherein neighborhoods of overlapping males and females affiliate with each other moreso than with other, more distantly located community members, and to the exclusion of members from adjacent communities.

animal behavior and cognition↗

bioRxiv2017

A Comment On Priors For Bayesian Occupancy Models

Understanding patterns of species occurrence and the processes underlying these patterns is fundamental to the study of ecology. One of the more commonly used approaches to investigate species occurrence patterns is occupancy modeling, which can account for imperfect detection of a species during surveys. In recent years, there has been a proliferation of Bayesian modeling in ecology, which includes fitting Bayesian occupancy models. The Bayesian framework is appealing to ecologists for many reasons, including the ability to incorporate prior information through the specification of prior distributions on parameters. While ecologists often intend to choose priors so that they are \"uninformative\"; or \";vague\";, such priors can easily be unintentionally highly informative. Here we report on how the specification of a \"vague\" normally distributed (i.e., Gaussian) prior on coefficients in Bayesian occupancy models can unintentionally influence parameter estimation. Using both simulation and empirical examples, we illustrate how this issue likely compromises inference about species-habitat relationships. While the occurrence of this issue likely depends on the data set, researchers fitting Bayesian occupancy models should conduct sensitivity analyses to ensure intended inference, or use priors other than those most commonly used in the literature. We provide further suggestions for addressing this issue in occupancy studies, and an online tool for exploring this issue under different contexts.

ecology↗