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Occupancy

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


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Journal ArticleDOI
TL;DR: A Bayesian hierarchical model is used to analyse camera trap data to quantify spatial patterns of habitat occupancy for lions and eight common ungulates of varying body size across an approximately 1100 km2 landscape in the Serengeti ecosystem and reveals strong positive associations among herbivores at the scale of the entire landscape.
Abstract: Herbivores play an important role in determining the structure and function of tropical savannahs. Here, we (i) outline a framework for how interactions among large mammalian herbivores, carnivores and environmental variation influence herbivore habitat occupancy in tropical savannahs. We then (ii) use a Bayesian hierarchical model to analyse camera trap data to quantify spatial patterns of habitat occupancy for lions and eight common ungulates of varying body size across an approximately 1100 km(2) landscape in the Serengeti ecosystem. Our results reveal strong positive associations among herbivores at the scale of the entire landscape. Lions were positively associated with migratory ungulates but negatively associated with residents. Herbivore habitat occupancy differed with body size and migratory strategy: large-bodied migrants, at less risk of predation and able to tolerate lower quality food, were associated with high NDVI, while smaller residents, constrained to higher quality forage, avoided these areas. Small herbivores were strongly associated with fires, likely due to the subsequent high-quality regrowth, while larger herbivores avoided burned areas. Body mass was strongly related to herbivore habitat use, with larger species more strongly associated with riverine and woodlands than smaller species. Large-bodied migrants displayed diffuse habitat occupancy, whereas smaller species demonstrated fine-scale occupancy reflecting use of smaller patches of high-quality habitat. Our results demonstrate the emergence of strong positive spatial associations among a diverse group of savannah herbivores, while highlighting species-specific habitat selection strongly determined by herbivore body size.This article is part of the themed issue 'Tropical grassy biomes: linking ecology, human use and conservation'.

67 citations

Journal ArticleDOI
TL;DR: This study shows that a profitable approach to ascertaining the nature of human impacts is to link intra- and interspecific processes, in the case of British farmland and woodland birds, changes to the environment lead to species-specific responses in large-scale distributions.
Abstract: 1. Range size, population size and body size, the key macroecological variables, vary temporally both within and across species in response to anthropogenic and natural environmental change. However, resulting temporal trends in the relationships between these variables (i.e. macroecological patterns) have received little attention. 2. Positive relationships between the local abundance and regional occupancy of species (abundance-occupancy relationships) are among the most pervasive of all macroecological patterns. In the absence of formal predictions of how abundance-occupancy relationships may vary temporally, we outline several scenarios of how changes in abundance within species might affect interspecific patterns. 3. We use data on the distribution and abundance of 73 farmland and 55 woodland bird species in Britain over a 32-year period encompassing substantial habitat modification to assess the likelihood of these scenarios. 4. In both farmland and woodland habitats, the interspecific abundance-occupancy relationship changed markedly over the period 1968-99, with a significant decline in the strength of the relationship. 5. Consideration of intraspecific dynamics shows that this has been due to a decoupling of abundance and occupancy particularly in rare and declining species. Insights into the intraspecific processes responsible for the interspecific trend are obtained by analysis of temporal trends in the distribution of individuals between sites, which show patterns consistent with habitat quality declines. 6. This study shows that a profitable approach to ascertaining the nature of human impacts is to link intra- and interspecific processes. In the case of British farmland and woodland birds, changes to the environment lead to species-specific responses in large-scale distributions. These species-specific changes are the driver of the observed changes in the form and strength of the interspecific relationship.

67 citations

Journal ArticleDOI
TL;DR: The authors investigated the shape(s) of the relationship between the probability of occupancy of a given location and macro-climate, and its consistency among species and regions, concluding that despite the complexities of species histories and biologies, to a first approximation most of the variation in their geographic distributions relates to climate, in similar ways for nearly all species.
Abstract: Aim Although many factors undoubtedly affect species geographic distributions, can a single, simple model nonetheless capture most of the spatial variation in the probability of presence/absence in a large set of species? For 482 North American tree species that occur east of the Rocky Mountains, we investigated the shape(s) of the relationship between the probability of occupancy of a given location and macroclimate, and its consistency among species and regions. Location North America. Methods Using Little's tree range maps, we tested four hypothetical shapes of response relating occupancy to climate: (1) high occupancy of all suitable climates; (2) threshold response (i.e. unsuitable climates exclude species, but within the thresholds, species presence is independent of climate); (3) occupancy is a bivariate normal function of annual temperature and precipitation; and (4) asymmetric limitation (i.e. abiotic factors set abrupt range limits in stressful climates only). Finally, we compared observed climatic niches with the occupancy of similar climates on off-shore islands as well as west of the Rockies. Results (a) Species' distributions in climatic space do not have strong thresholds, nor are they systematically skewed towards less stressful climates. (b) Occupancy can generally be described by a bivariate normal function of temperature and precipitation, with little or no interaction between the two variables. This model, averaged over all species, accounts for 82% of the spatial variation in the probability of occupancy of a given area. (c) Occupied geographic ranges are typically ringed by unoccupied, but climatically suitable areas. (d) Observed climatic niche positions are largely conserved between regions. Main conclusions We conclude that, despite the complexities of species histories and biologies, to a first approximation most of the variation in their geographic distributions relates to climate, in similar ways for nearly all species.

67 citations

Journal ArticleDOI
TL;DR: In this article, the authors quantify the effects of users, building parameters and systems on the performance and maintenance of hospital buildings, and employ coefficients and diagrams to quantify the effect of these parameters and variables.
Abstract: Maintenance management of health care facilities is one of the more complex subjects in the field of maintenance. The performance of hospital buildings is affected by numerous factors, including quality of hospital maintenance, actual occupancy vs standard occupancy, age of buildings, surrounding infrastructures, etc. The purpose of this research was to quantify the effects of users, building parameters and systems on the performance and maintenance of hospital buildings. The following factors were investigated: overall performance of the building; age of the building; level of building occupancy; and extent of labor outsourcing. The effects of the above parameters and variables were examined and quantified, employing coefficients and diagrams, using analytical and statistical analysis. The coefficients and diagrams developed were integrated into four key performance indicators for hospital buildings. The model was tested on six case studies, one of which is presented here.

67 citations

Journal ArticleDOI
TL;DR: Across the avian community, the landscape matrix influenced local extinction more than local colonization, indicating that extinction processes, rather than movement, likely drive interspecific differences in occupancy dynamics.
Abstract: In addition to patch-level attributes (i.e., area and isolation), the nature of land cover between habitat patches (the matrix) may drive colonization and extinction dynamics in fragmented landscapes. Despite a long-standing recognition of matrix effects in fragmented systems, an understanding of the relative impacts of different types of land cover on patterns and dynamics of species occurrence remains limited. We employed multi-season occupancy models to determine the relative influence of patch area, patch isolation, within-patch vegetation structure, and landscape matrix on occupancy dynamics of nine Neotropical insectivorous birds in 99 forest patches embedded in four matrix types (agriculture, suburban development, bauxite mining, and forest) in central Jamaica. We found that within-patch vegetation structure and the matrix type between patches were more important than patch area and patch isolation in determining local colonization and local extinction probabilities, and that the effects of patch area, isolation, and vegetation structure on occupancy dynamics tended to be matrix and species dependent. Across the avian community, the landscape matrix influenced local extinction more than local colonization, indicating that extinction processes, rather than movement, likely drive interspecific differences in occupancy dynamics. These findings lend crucial empirical support to the hypothesis that species occupancy dynamics in fragmented systems may depend greatly upon the landscape context.

67 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
2023669
20221,420
2021234
2020217
2019236
2018209