Patchy Reaction‐Diffusion and Population Abundance: The Relative Importance of Habitat Amount and Arrangement

Flather, Curtis H.; Bevers, Michael

doi:10.1086/324120

Cited by 271 publications

(126 citation statements)

References 74 publications

(116 reference statements)

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“…This assumption is commonly used in network-based studies that explore non-uniform adjacencies (e.g., Ball et al 1997), CA models that use long-range, probabilitybased dispersal kernels (e.g., Hargrove et al 2000;Flather and Bevers 2002) and stratified-diffusion models (e.g., Shigesada et al 1995).…”

Section: Methodsmentioning

confidence: 99%

Initial conditions and their effect on invasion velocity across heterogeneous landscapes

Ferrari

Lookingbill

2008

Biol Invasions

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Accurate, time dependent control options are required to halt biological invasions prior to equilibrium establishment, beyond which control efforts are often impractical. Although invasions have been successfully modeled using diffusion theory, diffusion models are typically confined to providing simple range expansion estimates. In this work, we use a Susceptible/Infected cellular automaton (CA) to simulate diffusion. The CA model is coupled with a network model to track the speed and direction of simulated invasions across heterogeneous landscapes, allowing for identification of locations for targeted control in both time and space. We evaluated the role of the location of initial establishment insofar as it affected the pattern and rate of spread and how these are influenced by patch attributes such as size. Our results show that the location of initial establishment can significantly affect the temporal dynamics of an invasion. Traditional network metrics such as degree and measures of topological distance were insufficient for predicting the direction and speed of the invasion. Our coupled models allow the dynamic tracking of invasions across fragmented landscapes for both theoretical and practical applications.

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Section: Methodsmentioning

confidence: 99%

Initial conditions and their effect on invasion velocity across heterogeneous landscapes

Ferrari

Lookingbill

2008

Biol Invasions

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“…The fragmentation threshold is reached once 70% of natural habitat is lost, whereafter the spatial configuration of habitat patches becomes important for the persistence of remaining species. 43 (b) Extrapolated rates of habitat loss in the Ingonyama Trust Board (ITB) and non-ITB areas.…”

Section: Agriculturementioning

confidence: 99%

“…Flather and Bevers 43 identified a persistence threshold that exists once natural habitat is reduced below 50% of the total landscape for low degrees of patch aggregation. Beyond this level of transformation there is a rapid decline in the probability of landscapes supporting viable populations of organisms and a decline in habitat connectivity.…”

Section: The Implications Of Habitat Lossmentioning

confidence: 99%

Systematic land-cover change in KwaZulu-Natal, South Africa: Implications for biodiversity

Jewitt¹,

Goodman²,

Erasmus³

et al. 2015

S. Afr. J. Sci.

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Land-cover change and habitat loss are widely recognised as the major drivers of biodiversity loss in the world. Land-cover maps derived from satellite imagery provide useful tools for monitoring land-use and land-cover change. KwaZulu-Natal, a populous yet biodiversity-rich province in South Africa, is one of the first provinces to produce a set of three directly comparable land-cover maps (2005, 2008 and 2011). These maps were used to investigate systematic land-cover changes occurring in the province with a focus on biodiversity conservation. The Intensity Analysis framework was used for the analysis as this quantitative hierarchical method addresses shortcomings of other established land-cover change analyses. In only 6 years (2005)(2006)(2007)(2008)(2009)(2010)(2011), a massive 7.6% of the natural habitat of the province was lost to anthropogenic transformation of the landscape. The major drivers of habitat loss were agriculture, timber plantations, the built environment, dams and mines. Categorical swapping formed a significant part of landscape change, including a return from anthropogenic categories to secondary vegetation, which we suggest should be tracked in analyses. Longer-term rates of habitat loss were determined using additional land-cover maps (1994, 2000). An average of 1.2% of the natural landscape has been transformed per annum since 1994. Apart from the direct loss of natural habitat, the anthropogenically transformed land covers all pose additional negative impacts for biodiversity remaining in these or surrounding areas. A target of no more than 50% of habitat loss should be adopted to adequately conserve biodiversity in the province. Our analysis provides the first provincial assessment of the rate of loss of natural habitat and may be used to fulfil incomplete criteria used in the identification of Threatened Terrestrial Ecosystems, and to report on the Convention on Biological Diversity targets on rates of natural habitat loss.

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“…The extinction threshold hypothesis states that many species require a given amount of suitable habitat to persist in the landscape. Fragmentation has its most pronounced effects at values that are below this threshold and can lead to abrupt decreases in species population size [4], [9], [10]. Extinction thresholds are proposed to occur when less than 30% of habitat remains, due to a decrease in mean patch size and to an exponential increase in the distance between patches [4], [8].…”

Section: Introductionmentioning

confidence: 99%

Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest

et al. 2015

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Habitat loss is the dominant threat to biodiversity and ecosystem functioning in terrestrial environments. In this study, we used an a priori classification of bird species based on their dependence on native forest habitats (forest-specialist and habitat generalists) and specific food resources (frugivores and insectivores) to evaluate their responses to forest cover reduction in landscapes in the Brazilian Atlantic Forest. From the patch-landscapes approach, we delimited 40 forest sites, and quantified the percentage of native forest within a 2 km radius around the center of each site (from 6 - 85%). At each site, we sampled birds using the point-count method. We used a null model, a generalized linear model and a four-parameter logistic model to evaluate the relationship between richness and abundance of the bird groups and the native forest amount. A piecewise model was then used to determine the threshold value for bird groups that showed nonlinear responses. The richness and abundance of the bird community as a whole were not affected by changes in forest cover in this region. However, a decrease in forest cover had a negative effect on diversity of forest-specialist, frugivorous and insectivorous birds, and a positive effect on generalist birds. The species richness and abundance of all ecological groups were nonlinearly related to forest reduction and showed similar threshold values, i.e., there were abrupt changes in individuals and species numbers when forest amount was less than approximately 50%. Forest sites within landscapes with forest cover that was less than 50% contained a different bird species composition than more extensively forested sites and had fewer forest-specialist species and higher beta-diversity. Our study demonstrated the pervasive effect of forest reduction on bird communities in one of the most important hotspots for bird conservation and shows that many vulnerable species require extensive forest cover to persist.

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Patchy Reaction‐Diffusion and Population Abundance: The Relative Importance of Habitat Amount and Arrangement

Cited by 271 publications

References 74 publications

Initial conditions and their effect on invasion velocity across heterogeneous landscapes

Initial conditions and their effect on invasion velocity across heterogeneous landscapes

Systematic land-cover change in KwaZulu-Natal, South Africa: Implications for biodiversity

Birds in Anthropogenic Landscapes: The Responses of Ecological Groups to Forest Loss in the Brazilian Atlantic Forest

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