Occupancy

About: Occupancy is a research topic. Over the lifetime, 2757 publications have been published within this topic receiving 68288 citations.

Associations between forest fire and Mexican spotted owls

Abstract: In 1993, the US Fish and Wildlife Service listed the Mexican spotted owl (Strix occidentalis lucida) as threatened, in part because of the rising threat to its habitat from stand-replacing wildfires. In 1997, we surveyed 33 owl sites that, in the previous four years, had burned at various levels ranging from light controlled burns to stand-replacing fires. We compared owl occupancy and reproduction in these burned sites to 31 unburned owl sites with similar habitat and topography. Although unburned sites showed higher proportions of both occupancy and reproduction, the negative relationship observed between recent fire occurrence and owl occupancy rank was statistically weak (Test for Marginal Homogeneity, P = 0.110). Owls tended not to be present where pure pine stands (Pinus spp.) comprised a large proportion (38-85%) of burned sites, but no other factors relating to habitat or fire severity had a significant, biologically interpretable influence on occupancy rank. We suspect that relatively low-intensity ground fires, including most prescribed fires, probably have little or no short-term impact on Mexican spotted owl presence or reproduction, but we have no data on long-term effects of fire. We recommend proactive fuels-management treatments in areas not currently occupied by owls as a means of reducing fire risk in areas occupied by owls. Within areas occupied by owls, judicious treatments may be appropriate after case-by-case evaluations of potential benefits and risks within those sites.

Using multilevel spatial models to understand salamander site occupancy patterns after wildfire.

Abstract: Studies of the distribution of elusive forest wildlife have suffered from the confounding of true presence with the uncertainty of detection. Occupancy modeling, which incorporates probabilities of species detection conditional on presence, is an emerging approach for reducing observation bias. However, the current likelihood modeling framework is restrictive for handling unexplained sources of variation in the response that may occur when there are dependence structures such as smaller sampling units that are nested within larger sampling units. We used multilevel Bayesian occupancy modeling to handle dependence structures and to partition sources of variation in occupancy of sites by terrestrial salamanders (family Plethodontidae) within and surrounding an earlier wildfire in western Oregon, USA. Comparison of model fit favored a spatial N-mixture model that accounted for variation in salamander abundance over models that were based on binary detection/non-detection data. Though catch per unit effort wa...

PLCount: A Probabilistic Fusion Algorithm for Accurately Estimating Occupancy from 3D Camera Counts

Abstract: The number of occupants in a whole building, a zone or a room is an important parameter when improving the energy efficiency of a building Using camera-based 3D or thermal sensors to detect passing of count lines are becoming more and more common However, such sensors are not perfect and errors add up over time In this paper we present the PLCount algorithm to accurately estimate total building, zone or room counts by fusing data from multiple count lines The algorithm applies probabilistic reasoning together with occupancy constraints to accurately estimate the total number of occupants We evaluate the algorithm on two data-sets from a small and a large office building The evaluation shows a considerably lower RMSE compared to the raw counts and naive correction approach with up to 86% and 70% error reduction respectively and similarity analysis of consecutive weeks demonstrate the stability of the algorithm over time We also demonstrate the use of the data for analyzing the energy consumption of a building By presenting more accurate algorithms for estimating total occupancy we hope to enable buildings to better serve the actual number of occupants to improve comfort and energy efficiency of buildings