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Journal ArticleDOI

The importance of microhabitat structure in maintaining forest mammal diversity in a mixed land-use mosaic

08 May 2017-Biodiversity and Conservation (Springer Netherlands)-Vol. 26, Iss: 10, pp 2361-2382
TL;DR: In this article, the authors investigated the influence of microhabitat complexity on mammal communities within forest and dense bush habitats, using occupancy modelling, and found vertical stratification gradients as observed in studies of tropical forest chronosequence, i.e. increased foliage density in lower habitat layers and decreased foliage density at higher habitat layers for dense bush, and vice versa for forest.
Abstract: The Indian Ocean Coastal Belt (IOCB) of South Africa is a natural forest-grassland mosaic, nested within an anthropogenic, mixed land-use matrix. Given the ongoing threat of agricultural expansion and urbanisation, we assessed the value of a buffer habitat (Coastal dense bush) for conserving forest species. We investigated the influence of microhabitat complexity on mammal communities within forest and dense bush habitats, using occupancy modelling. We found vertical stratification gradients as observed in studies of tropical forest chronosequence, i.e. increased foliage density in lower habitat layers and decreased foliage density in higher habitat layers for dense bush, and vice versa for forest. Structural composition suggests that dense bush is within a successional stage of secondary forest regeneration. Bushbuck (Tragelaphus scriptus) occupancy was higher in forest than dense bush, while the opposite was true for blue duiker (Philantomba monticola). Large-spotted genet (Genetta tigrina), Cape porcupine (Hystrix africaeaustralis) and marsh mongoose (Atilax paludinosus) occupancy remained constant between habitats. Grey duiker (Sylvicapra grimmia) occupancy varied greatly between dense bush (0.48 ± 0.01) and forest (0.16 ± 0.01). Dense bush appeared to maintain natural forest assemblages, and may play a crucial role in buffering IOCB forest patches, given their highly-restricted distribution. However, dense bush habitats have no protection status, but play a role in the conservation of forest plants and animals. Therefore, we advocate the inclusion of dense bush habitats in conservation networks focused on forests.
Citations
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Journal ArticleDOI
TL;DR: In this article, the authors studied the amphibian community of a hedgerow network landscape in western France and found that amphibian diversity was positively influenced by breeding site vegetation and also ponds density in the surrounding landscape.

37 citations

Journal ArticleDOI
TL;DR: A conceptual model to predict faunal responses to fire edges is developed and designed as a Bayesian Network, a statistical tool capable of analyzing complex environmental relationships, dealing with data gaps, and generating testable hypotheses.
Abstract: Edges are ecologically important environmental features and have been well researched in agricultural and urban landscapes. However, little work has been conducted in flammable ecosystems where spatially and temporally dynamic fire edges are expected to influence important processes such as recolonization of burnt areas and landscape connectivity. We review the literature on fire, fauna, and edge effects to summarize current knowledge of faunal responses to fire edges and identify knowledge gaps. We then develop a conceptual model to predict faunal responses to fire edges and present an agenda for future research. Faunal abundance at fire edges changes over time, but patterns depend on species traits and resource availability. Responses are also influenced by edge architecture (e.g., size and shape), site and landscape context, and spatial scale. However, data are limited and the influence of fire edges on both local abundance and regional distributions of fauna is largely unknown. In our conceptual model, biophysical properties interact with the fire regime (e.g., patchiness, frequency) to influence edge architecture. Edge architecture and species traits influence edge permeability, which is linked to important processes such as movement, resource selection, and species interactions. Predicting the effect of fire edges on fauna is challenging, but important for biodiversity conservation in flammable landscapes. Our conceptual model combines several drivers of faunal fire responses (biophysical properties, regime attributes, species traits) and will therefore lead to improved predictions. Future research is needed to understand fire as an agent of edge creation; the spatio-temporal flux of fire edges across landscapes; and the effect of fire edges on faunal movement, resource selection, and biotic interactions. To aid the incorporation of new data into our predictive framework, our model has been designed as a Bayesian Network, a statistical tool capable of analyzing complex environmental relationships, dealing with data gaps, and generating testable hypotheses.

30 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the influence of protected areas (PAs), agriculture and urbanisation on the occupancy of mammal communities in an anthropogenic matrix containing indigenous forest fragments of the Coastal Belt of southern KwaZulu-Natal, South Africa.
Abstract: Conservation planning for biodiversity within anthropogenic landscapes is crucial given the rate of habitat conversion and human population growth. Investigating anthropogenic impacts on the persistence of biodiversity is key to management decision-making. We investigated the influence of protected areas (PAs), agriculture and urbanisation on the occupancy of mammal communities in an anthropogenic matrix containing indigenous forest fragments of the Coastal Belt of southern KwaZulu-Natal, South Africa. We integrated camera-trap mammal data, land-use and human population density within occupancy models, and compared occupancy of individual species across the land-use mosaic. We modelled occupancy of seven mammal species with sufficient naive occupancy (> 0.20, range 0.25–0.87). The occupancy of Philantomba monticola was positively influenced by human population size and was higher within urban areas compared with PAs. Although human population size positively affected Hystrix africaeaustralis occupancy, it along with Atilax paludinosus had a lower occupancy within urban areas. Tragelaphus scriptus and Potamochoerus larvatus overall had higher and Sylvicapra grimmia had lower occupancies within PAs. Species were variable in their response to the anthropogenic changes in the landscape. For example, occupancy of P. monticola was low within PAs but high in areas where change in land ownership and loss of habitat are threats. For other species, it appeared that the density of infrastructure of the urban landscape, rather than human population density, affected them negatively. However, seasonal differences within different management regimes also provided context-specific influences on occupancy and detectability. We emphasize the importance of natural vegetation patches within anthropogenic landscapes for maintaining native fauna, whilst stressing the value of temporally replicated, multi-species, regional-scale studies when making conservation decisions.

29 citations


Cites background or methods or result from "The importance of microhabitat stru..."

  • ...This ensured that the number of survey points where evenly distributed across habitat types, forest and dense bush, as well as management types (Bibby et al. 2000; Ehlers Smith et al. 2015, 2017)....

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  • ...Occupancy and detectability may additionally be influenced by seasonal changes, particularly in relation to fine scale habitat features and vegetation cover and how those characteristics respond to rainfall (see Ehlers Smith et al. 2017 for species specificmicrohabitat influences)....

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  • ...The blue duiker and bushbuck (Tragelaphus scriptus) are forest species that exist within the forest and dense bush patches within the region (Ehlers Smith et al. 2017) and although red duiker (Cephalophus natalensis) are also considered forest species throughout their Africa-wide distribution…...

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  • ...…(Atilax paludinosus) and large-spotted genet (Genetta tigrina), that despite their larger distribution ranges and broader habitat preferences, also rely on the forest patches within the Coastal Forests and were also included within the occupancy modelling analysis (Ehlers Smith et al. 2017)....

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  • ...…region: (1) coastal scarp, and (2) lowland coastal forest; as well as extensive patches of thicket/dense bush (hereafter dense bush; Eeley et al. 1999; Mucina and Rutherford 2011; GeoTerraImage 2014), which are considered as secondary regenerating Coastal Belt Forest (Ehlers Smith et al. 2017)....

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Journal ArticleDOI
TL;DR: In this article, the effects of forest fragmentation via measures of patch size and isolation on the taxonomic richness and functional richness of forest bird communities in five Protected Areas within the urban-forest mosaic of the Durban Metropolitan Area, South Africa were described.
Abstract: Loss of habitat area and structural heterogeneity through anthropogenic fragmentation poses a threat to the survival of wildlife, which may be exacerbated by urban pressures. Understanding the underlying ecological processes that influence species’ persistence in fragmented landscapes is vital for conservation. We described the effects of forest fragmentation via measures of patch size and isolation on the taxonomic richness and functional richness of forest bird communities in five Protected Areas within the urban-forest mosaic of the Durban Metropolitan Area, South Africa. We conducted 137 fixed-radius point-count surveys across 41 distinct forest patches during the austral breeding season. We quantified the avian taxonomic, guild and functional richness and measured at each survey patch. We measured the influence of patch size, Euclidean isolation distance, patch shape and habitat configuration (i.e. habitat amount) on each diversity measure. We then conducted a series of General Linear Models to determine how fragmentation and patch configuration influenced the diversity of forest birds. The explanatory variables in the top models had a significant effect on all avian diversity measures but habitat amount did not. The amount of habitat surrounding a patch was not significant for measures of bird diversity but based on the Akaike’s weight it was important for specialist species. Isolation distance did not have a significant effect on the measures of bird diversity. An increase in patch shape index increased species richness. These results show the importance of large forest fragments/patches for the conservation of forest birds and for maintaining ecosystem functioning and services of forests in increasingly urbanising landscapes, to the benefit of the environment and its human population.

28 citations

References
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Journal Article
TL;DR: Copyright (©) 1999–2012 R Foundation for Statistical Computing; permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and permission notice are preserved on all copies.
Abstract: Copyright (©) 1999–2012 R Foundation for Statistical Computing. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that this permission notice may be stated in a translation approved by the R Core Team.

272,030 citations

Book
19 Jun 2013
TL;DR: The second edition of this book is unique in that it focuses on methods for making formal statistical inference from all the models in an a priori set (Multi-Model Inference).
Abstract: Introduction * Information and Likelihood Theory: A Basis for Model Selection and Inference * Basic Use of the Information-Theoretic Approach * Formal Inference From More Than One Model: Multi-Model Inference (MMI) * Monte Carlo Insights and Extended Examples * Statistical Theory and Numerical Results * Summary

36,993 citations

Journal Article
TL;DR: PAST (PAleontological STatistics) as discussed by the authors is a simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology.
Abstract: A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheet-type data entry with univariate and multivariate statistics, curve fitting, timeseries analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.

19,926 citations


"The importance of microhabitat stru..." refers methods in this paper

  • ...These analyses were performed within the program PAST 3.1 (Harper and Ryan 2001)....

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Journal ArticleDOI
TL;DR: In this article, the authors suggest that the term "fragmentation" should be reserved for the breaking apart of habitat, independent of habitat loss, and that fragmentation per se has much weaker effects on biodiversity that are at least as likely to be positive as negative.
Abstract: ■ Abstract The literature on effects of habitat fragmentation on biodiversity is huge. It is also very diverse, with different authors measuring fragmentation in different ways and, as a consequence, drawing different conclusions regarding both the magnitude and direction of its effects. Habitat fragmentation is usually defined as a landscape-scale process involving both habitat loss and the breaking apart of habitat. Results of empirical studies of habitat fragmentation are often difficult to interpret because (a) many researchers measure fragmentation at the patch scale, not the landscape scale and (b) most researchers measure fragmentation in ways that do not distinguish between habitat loss and habitat fragmentation per se, i.e., the breaking apart of habitat after controlling for habitat loss. Empirical studies to date suggest that habitat loss has large, consistently negative effects on biodiversity. Habitat fragmentation per se has much weaker effects on biodiversity that are at least as likely to be positive as negative. Therefore, to correctly interpret the influence of habitat fragmentation on biodiversity, the effects of these two components of fragmentation must be measured independently. More studies of the independent effects of habitat loss and fragmentation per se are needed to determine the factors that lead to positive versus negative effects of fragmentation per se. I suggest that the term “fragmentation” should be reserved for the breaking apart of habitat, independent of habitat loss.

6,341 citations

Journal ArticleDOI
28 May 2010-Science
TL;DR: Most indicators of the state of biodiversity showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity showed increases, indicating that the Convention on Biological Diversity’s 2010 targets have not been met.
Abstract: In 2002, world leaders committed, through the Convention on Biological Diversity, to achieve a significant reduction in the rate of biodiversity loss by 2010. We compiled 31 indicators to report on progress toward this target. Most indicators of the state of biodiversity (covering species' population trends, extinction risk, habitat extent and condition, and community composition) showed declines, with no significant recent reductions in rate, whereas indicators of pressures on biodiversity (including resource consumption, invasive alien species, nitrogen pollution, overexploitation, and climate change impacts) showed increases. Despite some local successes and increasing responses (including extent and biodiversity coverage of protected areas, sustainable forest management, policy responses to invasive alien species, and biodiversity-related aid), the rate of biodiversity loss does not appear to be slowing.

3,993 citations