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Count data arise frequently in ecological analyses, but regularly violate the equi-dispersion constraint imposed by the most popular distribution for analyzing these data, the Poisson distribution. Several approaches for addressing overdispersion have been developed (e.g., negative-binomial distribution) but methods for including both underdispersion and overdispersion have been largely overlooked. We provide three specific examples drawn from life history theory, spatial ecology, and community ecology and illustrate the use of the Conway-Maxwell Poisson (CMP) distribution as compared to other common models for count data. We find that where equi-dispersion is violated, the CMP distribution performs significantly...
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Abstract (from Ecological Society of America): Population dynamics are often correlated in space and time due to correlations in environmental drivers as well as synchrony induced by individual dispersal. Many statistical analyses of populations ignore potential autocorrelations and assume that survey methods (distance and time between samples) eliminate these correlations, allowing samples to be treated independently. If these assumptions are incorrect, results and therefore inference may be biased and uncertainty underestimated. We developed a novel statistical method to account for spatiotemporal correlations within dendritic stream networks, while accounting for imperfect detection in the surveys. Through simulations,...
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Managing natural populations and communities requires detailed information regarding demographic processes at large spatial and temporal scales. This combination is challenging for both traditional scientific surveys, which often operate at localized scales, and recent citizen science designs, which often provide data with few auxiliary information (i.e. no information about individual age or condition). We therefore combine citizen science data at large scales with the demographic resolution afforded by recently developed, site-structured demographic models. We apply this approach to categorical data generated from citizen science representing species density of two managed reef fishes in the Gulf of Mexico, and...
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This dataset contains count and detection-nondetection data of Barred Owls from 106 historical breeding territories of Northern Spotted Owl territories (i.e. sites) in the Oregon Coast Ranges from 1995 to 2016. Data collected from 1995 to 2014 are partitioned into 2-week periods from 1 March – 31 August each year, totaling 12 possible sampling periods per year. Data collected from 2015 and 2016 are partitioned into 2-month periods from 1 March – 31 August, totaling 3 possible sampling periods each year. This dataset also describes the proportion of total area surveyed per site per sampling period in 2015 and 2016, as well as the proportion of each site with older coniferous forest in each year (1995 – 2016).
Categories: Data;
Tags: Barred Owl,
Dail-Madsen model,
Ecology,
Forestry,
N-mixture model, All tags...
Oregon,
Oregon Coast Range,
Strix varia,
USGS Science Data Catalog (SDC),
Wildlife Biology,
biota,
detection probability,
integrated population model,
occupancy,
unmarked data, Fewer tags
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