Alan E. Gelfand

Journal Article Journal of Statistical Planning and Inference · May 1, 2025 A frequent challenge encountered in real-world applications is data having a high proportion of zeros. Focusing on ecological abundance data, much attention has been given to zero-inflated count data. Models for non-negative continuous abundance data with ... Full text Cite

ASSESSING MARINE MAMMAL ABUNDANCE: A NOVEL DATA FUSION

Journal Article Annals of Applied Statistics · December 1, 2024 Marine mammals are increasingly vulnerable to human disturbance and climate change. Their diving behavior leads to limited visual access during data collection, making studying the abundance and distribution of marine mammals challenging. In theory, using ... Full text Cite

Good modelling practice in ecology, the hierarchical Bayesian perspective

Journal Article Ecological Modelling · October 1, 2024 Ecological modelling often involves addressing challenges such as dependence in responses, e.g., spatial and/or temporal correlation, heterogeneity of variance, and hierarchical structures inherent in ecological processes and data. A constant challenge is ... Full text Cite

Bayesian joint quantile autoregression

Journal Article Test · March 1, 2024 Quantile regression continues to increase in usage, providing a useful alternative to customary mean regression. Primary implementation takes the form of so-called multiple quantile regression, creating a separate regression for each quantile of interest. ... Full text Cite

Generative spatial generalized dissimilarity mixed modelling (spGDMM): An enhanced approach to modelling beta diversity

Journal Article Methods in Ecology and Evolution · January 1, 2024 Turnover, or change in the composition of species over space and time, is one of the primary ways to define beta diversity. Inferring what factors impact beta diversity is not only important for understanding biodiversity processes but also for conservatio ... Full text Cite

Spatio-Temporal Modeling for Record-Breaking Temperature Events in Spain

Journal Article Journal of the American Statistical Association · January 1, 2024 Record-breaking temperature events are now very frequently in the news, viewed as evidence of climate change. With this as motivation, we undertake the first substantial spatial modeling investigation of temperature record-breaking across years for any giv ... Full text Cite

Assessing space and time changes in daily maximum temperature in the Ebro basin (Spain) using model-based statistical tools

Journal Article International Journal of Climatology · December 30, 2023 There is continuing interest in the investigation of change in temperature over space and time. For this analysis, we offer statistical tools to illuminate changes temporally, at desired temporal resolution, and spatially, using data generated from suitabl ... Full text Cite

Space-time multi-level modeling for zooplankton abundance employing double data fusion and calibration

Journal Article Environmental and Ecological Statistics · December 1, 2023 An important objective for marine biologists is to forecast the distribution and abundance of planktivorous marine predators. To do so, it is critically important to understand the spatiotemporal dynamics of their prey. Here, the prey we study are zooplank ... Full text Cite

Mechanistic modeling of climate effects on redistribution and population growth in a community of fish species.

Journal Article Global change biology · November 2023 Understanding community responses to climate is critical for anticipating the future impacts of global change. However, despite increased research efforts in this field, models that explicitly include important biological mechanisms are lacking. Quantifyin ... Full text Cite

Joint multivariate and functional modeling for plant traits and reflectances

Journal Article Environmental and Ecological Statistics · September 1, 2023 The investigation of leaf-level traits in response to varying environmental conditions has immense importance for understanding plant ecology. Remote sensing technology enables measurement of the reflectance of plants to make inferences about underlying tr ... Full text Cite

SPATIAL QUANTILE AUTOREGRESSION FOR SEASON WITHIN YEAR DAILY MAXIMUM TEMPERATURE DATA

Journal Article Annals of Applied Statistics · September 1, 2023 Regression is the most widely used modeling tool in statistics. Quantile regression offers a strategy for enhancing the regression picture beyond cus-tomary mean regression. With time-series data, we move to quantile autore-gression and, finally, with spat ... Full text Cite

Data from: Mechanistic modeling of climate effects on redistribution and population growth in a community of fish species.

Dataset · August 29, 2023 Understanding community responses to climate is critical for anticipating the future impacts of global change. However, despite increased research efforts in this field, models that explicitly include important biological mechanisms are lacking. Quantifyin ... Full text Cite

Zero-Inflated Beta Distribution Regression Modeling

Journal Article Journal of Agricultural, Biological, and Environmental Statistics · March 1, 2023 A frequent challenge encountered with ecological data is how to interpret, analyze, or model data having a high proportion of zeros. Much attention has been given to zero-inflated count data, whereas models for non-negative continuous data with an abundanc ... Full text Cite

Modeling Community Dynamics Through Environmental Effects, Species Interactions and Movement

Journal Article Journal of Agricultural, Biological, and Environmental Statistics · March 1, 2023 Understanding how communities respond to environmental change is frustrated by the fact that both species interactions and movement affect biodiversity in unseen ways. To evaluate the contributions of species interactions on community growth, dynamic model ... Full text Cite

TIME-DISCRETIZATION APPROXIMATION ENRICHES CONTINUOUS-TIME DISCRETE-SPACE MODELS FOR ANIMAL MOVEMENT

Journal Article Annals of Applied Statistics · March 1, 2023 Continuous time discrete state models are a valuable tool for explaining animal movement. However, data collection to fit such models over a spec-ified window of time can be misaligned with the actual realization of the movement process. This necessitates ... Full text Cite

Kernel density estimation of conditional distributions to detect responses in satellite tag data

Journal Article Animal Biotelemetry · December 1, 2022 Background: As levels of anthropogenic noise in the marine environment rise, it is crucial to quantify potential associated effects on marine mammals. Yet measuring responses is challenging because most species spend the majority of their time submerged. C ... Full text Cite

Preferential sampling for bivariate spatial data

Journal Article Spatial Statistics · October 1, 2022 Preferential sampling provides a formal modeling specification to capture the effect of bias in a set of sampling locations on inference when a geostatistical model is used to explain observed responses at the sampled locations. In particular, it enables m ... Full text Cite

Spatio-temporal analysis of the extent of an extreme heat event

Journal Article Stochastic Environmental Research and Risk Assessment · September 1, 2022 Evidence of global warming induced from the increasing concentration of greenhouse gases in the atmosphere suggests more frequent warm days and heat waves. The concept of an extreme heat event (EHE), defined locally based on exceedance of a suitable local ... Full text Cite

Spatial Modeling of Day-Within-Year Temperature Time Series: An Examination of Daily Maximum Temperatures in Aragón, Spain

Journal Article Journal of Agricultural, Biological, and Environmental Statistics · September 1, 2022 Acknowledging a considerable literature on modeling daily temperature data, we propose a multi-level spatiotemporal model which introduces several innovations in order to explain the daily maximum temperature in the summer period over 60 years in a region ... Full text Cite

SPATIAL FUNCTIONAL DATA MODELING OF PLANT REFLECTANCES

Journal Article Annals of Applied Statistics · September 1, 2022 Plant reflectance spectra, the profile of light reflected by leaves across different wavelengths, supply the spectral signature for a species at a spatial location to enable estimation of functional and taxonomic diversity for plants. We consider leaf spec ... Full text Cite