Assessing the Significance of the Correlation between Two Spatial Processes

Clifford, Peter; Richardson, Sylvia; Hémon, Denis

doi:10.2307/2532039

Cited by 520 publications

(453 citation statements)

References 17 publications

Supporting

Mentioning

440

Contrasting

Unclassified

Order By: Relevance

“…This relationship is, however, not significant when corrected for spatial autocorrelation (Spearman rho ¼ 0.64, ess ¼ 5.78, ns; ess -'effective sample size', when redundancy produced by spatial autocorrelation is removed using the modified correlation test of Clifford et al (1989)). The relationship becomes stronger when only negative values of the first axis are taken into account (Spearman rho ¼ 0.71, ess ¼ 6.64, p < 0.05), because variance spreads for positive values along PCA axis 1.…”

Section: Species Diversity As Surrogate For Environmental Diversitymentioning

confidence: 93%

Capturing biodiversity: selecting priority areas for conservation using different criteria

2005

View full text Add to dashboard Cite

Abstract. International treaties call for the protection of biodiversity in all its manifestations, including ecosystem and species diversities. The selection of most priority area networks focuses, however, primarily on species richness and occurrence. The effectiveness of this approach in capturing higher order manifestations of biodiversity, that is ecosystem and environmental diversity patterns, remains poorly understood. Using a case study of birds and environmental data from South Africa and Lesotho, we test how complementary networks that maximise species diversity perform with regard to their representation of ecosystem and environmental diversity, and vice versa. We compare these results to the performance of the existing reserve network. We conclude that focusing on any single biodiversity component alone is insufficient to protect other components. We offer explanations for this in terms of the autocorrelation of species diversity in environmental space.

show abstract

Section: Species Diversity As Surrogate For Environmental Diversitymentioning

confidence: 93%

Capturing biodiversity: selecting priority areas for conservation using different criteria

2005

View full text Add to dashboard Cite

show abstract

“…2a). This correlation remains highly significant (corrected F ϭ 78.49, corrected P Ͻ 0.001, n ϭ 4,152: based on a subsample of cells and excluding single species occurrences) when degrees of freedom are reduced to account for spatial autocorrelation (26). Moving to phylogeny, places where a high proportion of species are on short terminal branches in the tree are likely to have rapid diversification, turnover, or immigration in their recent history (27).…”

Section: A Snapshot Of Mammalian Biodiversitymentioning

confidence: 99%

Phylogenetic trees and the future of mammalian biodiversity

Davies

Fritz²,

Grenyer

et al. 2008

Proc. Natl. Acad. Sci. U.S.A.

136

161

View full text Add to dashboard Cite

Phylogenies describe the origins and history of species. However, they can also help to predict species' fates and so can be useful tools for managing the future of biodiversity. This article starts by sketching how phylogenetic, geographic, and trait information can be combined to elucidate present mammalian diversity patterns and how they arose. Recent diversification rates and standing diversity show different geographic patterns, indicating that cradles of diversity have moved over time. Patterns in extinction risk reflect both biological differences among mammalian lineages and differences in threat intensity among regions. Phylogenetic comparative analyses indicate that for small-bodied mammals, extinction risk is governed mostly by where the species live and the intensity of the threats, whereas for large-bodied mammals, ecological differences also play an important role. This modeling approach identifies species whose intrinsic biology renders them particularly vulnerable to increased human pressure. We outline how the approach might be extended to consider future trends in anthropogenic drivers, to identify likely future battlegrounds of mammalian conservation, and the likely casualties. This framework could help to highlight consequences of choosing among different future climatic and socioeconomic scenarios. We end by discussing priority-setting, showing how alternative currencies for diversity can suggest very different priorities. We argue that aiming to maximize long-term evolutionary responses is inappropriate, that conservation planning needs to consider costs as well as benefits, and that proactive conservation of largely intact systems should be part of a balanced strategy. extinction risk ͉ latent risk ͉ mammals T he Tree of Life-phylogeny-is a powerful metaphor for life's diversity, showing all species, including our own, as part of an interrelated whole. But phylogeny is more than a metaphor. It is also a research tool-the result of evolutionary processes integrated over the history of life, it can be analyzed for insights into how those processes have shaped today's biota (1). This approach is becoming increasingly powerful as the trees become ever more inclusive, built from rapidly accumulating databases using methods that continue to be improved (2, 3).Species' histories are of interest, but their futures are of more pressing concern. The Tree of Life is currently under sustained attack, as people increasingly dominate landscapes (4). Comparisons of extinction rates between today and geological history are difficult for many reasons (5), but the Tree of Life is already being pruned more quickly than it is growing (6), and extinction rates are projected to rise by at least another order of magnitude over the next centuries (7). This article describes how phylogeny has a role to play in understanding the pattern of survivors and casualties and how it can help us both to predict species' futures and to estimate some of the biodiversity value that would be lost if they went extinct.We focus o...

show abstract

“…Locations and sampling time were chosen so as to reduce dependence among sites, thus preventing spatial autocorrelation and double counts between locations. Spatial autocorrelation can influence the null distribution of Pearson's R (referred to as R hereafter, and presented with the p value and the sample size n; Sokal and Rohlf 1995), leading to overestimating the number of degrees of freedom, and may therefore elevate the probability of a Type I error (Clifford et al 1989). The PASSAGE software was used (available at http:// www.passagesoftware.net/) to run a modified t-test for correlation, following Clifford et al (1989).…”

Section: Sampling Designmentioning

confidence: 99%

Accurate prediction of bird species richness patterns in an urban environment using Landsat‐derived NDVI and spectral unmixing

Bino

Levin

Darawshi

et al. 2008

International Journal of Remote Sensing

View full text Add to dashboard Cite

Urban landscapes are expanding rapidly and are reshaping the distribution of many animal and plant species. With these changes, the need to understand and to include urban biodiversity patterns in research and management programmes is becoming vital. Recent studies have shown that remote sensing tools can be useful in studies examining biodiversity patterns in natural landscapes. The present study aimed to explore whether remote sensing tools can be applied in biodiversity research in an urban landscape. More specifically, the study examined whether the Landsat-derived Normalized Difference Vegetation Index (NDVI) and linear spectral unmixing of urban land cover can predict bird richness in the city of Jerusalem. Bird richness was sampled in 40 1-ha sites over a range of urban environments in 329 surveys. NDVI and the per cent cover of built-up area were strongly and negatively correlated with each other, and were both very successful in explaining the number of bird species in the study sites. Mean NDVI in each site was positively correlated with the site bird species richness. A hump-shaped relationship between NDVI and species richness was observed (when calculated over increasing spatial scales), with a maximum value (Pearson's R50.87, p,0.001, n540) at a scale of 15 ha. We suggest that remote sensing approaches may provide planners and conservation biologists with an efficient and cost-effective method to study and estimate biodiversity across urban environments that range between densely built-up areas, residential neighbourhoods, urban parks and the peri-urban environment.

show abstract

Assessing the Significance of the Correlation between Two Spatial Processes

Cited by 520 publications

References 17 publications

Capturing biodiversity: selecting priority areas for conservation using different criteria

Capturing biodiversity: selecting priority areas for conservation using different criteria

Phylogenetic trees and the future of mammalian biodiversity

Accurate prediction of bird species richness patterns in an urban environment using Landsat‐derived NDVI and spectral unmixing

Contact Info

Product

Resources

About