title: Dynamic N-occupancy models: estimating demographic rates and local abundance from detection-nondetection data.
abstract: Occupancy modeling is a widely used analytical technique for assessing species distributions and range dynamics. However, occupancy analyses frequently ignore variation in abundance of occupied sites, even though site abundances affect many of the parameters being estimated (e.g., extinction, colonization, detection probability). We introduce a new model ("dynamic N-occupancy") capable of providing accurate estimates of local abundance, population gains (reproduction/immigration), and apparent survival probabilities while accounting for imperfect detection using only detection/nondetection data. Our model utilizes heterogeneity in detection based on variations in site abundances to estimate latent demographic rates via a dynamic N-mixture modeling framework. We validate our model using simulations across a wide range of values and examine the data requirements, including the number of years and survey sites needed, for unbiased and precise estimation of parameters. We apply our model to estimate spatiotemporal heterogeneity in abundances of barred owls (Strix varia) within a recently invaded region in Oregon (USA). Estimates of apparent survival and population gains are consistent with those from a nearby radio-tracking study and elucidate how barred owl abundances have increased dramatically over time. The dynamic N-occupancy model greatly improves inferences on individual-level population processes from occupancy data by explicitly modeling the latent population structure.
authors.affiliation: Department of Integrative Biology, College of Natural Science, Michigan State University, 288 Farm Lane RM 203, East Lansing, Michigan, 48824, USA.|Hubbs-Sea World Research Institute, 3830 S. Highway A1A #4-181, Melbourne Beach, Florida, 32951, USA.
authors.forename: Sam
authors.initials: S
authors.lastname: Rossman
authors.affiliation: U.S. Geological Survey, Southwest Biological Science Center, 2255 N. Gemini Drive, Flagstaff, Arizona, 86001, USA.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Yackulic
authors.affiliation: Department of Integrative Biology, College of Natural Science, Michigan State University, 288 Farm Lane RM 203, East Lansing, Michigan, 48824, USA.
authors.forename: Sarah P
authors.initials: SP
authors.lastname: Saunders
authors.affiliation: U.S. Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, Oregon, 97331, USA.
authors.forename: Janice
authors.initials: J
authors.lastname: Reid
authors.affiliation: U.S. Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, Oregon, 97331, USA.
authors.forename: Ray
authors.initials: R
authors.lastname: Davis
authors.affiliation: Department of Integrative Biology, College of Natural Science, Michigan State University, 288 Farm Lane RM 203, East Lansing, Michigan, 48824, USA.|Ecology, Evolutionary Biology, and Behavior Program, Michigan State University, 293 Farm Lane RM 103, East Lansing, Michigan, 48824, USA.
authors.forename: Elise F
authors.initials: EF
authors.lastname: Zipkin
mesh_terms: D000818:Animals; D017753:Ecosystem; D008954:Models, Biological; D011157:Population Dynamics; D020305:Strigiformes / Q000502:physiology*
keywords: N-mixture model; barred owl; demographic rates; dynamic; heterogeneity; latent; occupancy; species distribution models