Occupancy

About: Occupancy is a(n) research topic. Over the lifetime, 2757 publication(s) have been published within this topic receiving 68288 citation(s).

Using occupancy grids for mobile robot perception and navigation

Abstract: An approach to robot perception and world modeling that uses a probabilistic tesselated representation of spatial information called the occupancy grid is reviewed. The occupancy grid is a multidimensional random field that maintains stochastic estimates of the occupancy state of the cells in a spatial lattice. To construct a sensor-derived map of the robot's world, the cell state estimates are obtained by interpreting the incoming range readings using probabilistic sensor models. Bayesian estimation procedures allow the incremental updating of the occupancy grid, using readings taken from several sensors over multiple points of view. The use of occupancy grids from mapping and for navigation is examined. Operations on occupancy grids and extensions of the occupancy grid framework are briefly considered. >

Occupancy Estimation and Modeling: Inferring Patterns and Dynamics of Species Occurrence

Abstract: Ch 1: Introduction Ch 2: Occupancy in Ecological Investigations Ch 3: Fundamental Principles of Statistical Inference Ch 4: Single-species, Single-season Occupancy Models Ch 5: Single-species, Single-season Models with Heterogeneous Detection Probabilities Ch 6: Design Issues for Single-species, Single-season Occupancy Models Ch 7: Single-species, Multiple-seasons Occupancy Models Ch 8: Examining the Local Species Pool Ch 9: Interspecific Relationships Between Species Ch10: Extensions and Future Work

Designing occupancy studies: general advice and allocating survey effort

Abstract: Summary 1 The fraction of sampling units in a landscape where a target species is present (occupancy) is an extensively used concept in ecology Yet in many applications the species will not always be detected in a sampling unit even when present, resulting in biased estimates of occupancy Given that sampling units are surveyed repeatedly within a relatively short timeframe, a number of similar methods have now been developed to provide unbiased occupancy estimates However, practical guidance on the efficient design of occupancy studies has been lacking 2 In this paper we comment on a number of general issues related to designing occupancy studies, including the need for clear objectives that are explicitly linked to science or management, selection of sampling units, timing of repeat surveys and allocation of survey effort Advice on the number of repeat surveys per sampling unit is considered in terms of the variance of the occupancy estimator, for three possible study designs 3 We recommend that sampling units should be surveyed a minimum of three times when detection probability is high (> 0·5 survey−1), unless a removal design is used 4 We found that an optimal removal design will generally be the most efficient, but we suggest it may be less robust to assumption violations than a standard design 5 Our results suggest that for a rare species it is more efficient to survey more sampling units less intensively, while for a common species fewer sampling units should be surveyed more intensively 6 Synthesis and applications Reliable inferences can only result from quality data To make the best use of logistical resources, study objectives must be clearly defined; sampling units must be selected, and repeated surveys timed appropriately; and a sufficient number of repeated surveys must be conducted Failure to do so may compromise the integrity of the study The guidance given here on study design issues is particularly applicable to studies of species occurrence and distribution, habitat selection and modelling, metapopulation studies and monitoring programmes

Effect of habitat area and isolation on fragmented animal populations

Abstract: Habitat destruction has driven many once-contiguous animal populations into remnant patches of varying size and isolation. The underlying framework for the conservation of fragmented populations is founded on the principles of island biogeography, wherein the probability of species occurrence in habitat patches varies as a function of patch size and isolation. Despite decades of research, the general importance of patch area and isolation as predictors of species occupancy in fragmented terrestrial systems remains unknown because of a lack of quantitative synthesis. Here, we compile occupancy data from 1,015 bird, mammal, reptile, amphibian, and invertebrate population networks on 6 continents and show that patch area and isolation are surprisingly poor predictors of occupancy for most species. We examine factors such as improper scaling and biases in species representation as explanations and find that the type of land cover separating patches most strongly affects the sensitivity of species to patch area and isolation. Our results indicate that patch area and isolation are indeed important factors affecting the occupancy of many species, but properties of the intervening matrix should not be ignored. Improving matrix quality may lead to higher conservation returns than manipulating the size and configuration of remnant patches for many of the species that persist in the aftermath of habitat destruction.