TY - JOUR

T1 - Scale-dependent species–area and species–isolation relationships

T2 - a review and a test study from a fragmented semi-arid agro-ecosystem

AU - Giladi, Itamar

AU - May, Felix

AU - Ristow, Michael

AU - Jeltsch, Florian

AU - Ziv, Yaron

N1 - Funded by German Israeli Foundation for Research and Development. Grant Number: 913-100.12/2006 Israel Science Foundation. Grant Number: 751/09

PY - 2014/6

Y1 - 2014/6

N2 - Aim: Patterns that relate species richness with fragment area (the species-area relationship, SAR) and with isolation (the species-isolation relationship, SIR) are well documented. However, those that relate species density - the number of species within a standardized area - with fragment area (D-SAR) or isolation (D-SIR) have not been sufficiently explored, despite the potential for such an analysis to disentangle the underlying mechanisms of SARs and SIRs. Previous spatial theory predicts that a significant D-SAR or D-SIR is unlikely to emerge in taxa with high dispersal limitation, such as plants. Furthermore, a recent model predicts that the detection and the significance of D-SARs or D-SIRs may decrease with grain size. We combined a literature review with grain size-dependent sampling in a fragmented landscape to evaluate the prevalence and grain size-dependent nature of D-SARs and D-SIRs in plants. Location: Worldwide (review) and a semi-arid agro-ecosystem in Israel (case study). Methods: We combined an extensive literature review of 31 D-SAR studies of plants in fragmented landscapes with an empirical study in which we analysed grain size-dependent D-SARs and D-SIRs using a grain size-dependent hierarchical sampling of species density and species richness in a fragmented, semi-arid agro-ecosystem. Results: We found that significantly increasing D-SARs are rare in plant studies. Furthermore, we found that the detection of a significant D-SAR is often possible only after the data have been stratified by species, habitat or landscape characteristics. The results from our case study indicated that the significance and the slopes of both D-SARs and D-SIRs increase as grain size decreases. Main conclusions: These results call for a careful consideration of scale while analysing and interpreting the responses of species richness and species density to fragmentation. Our results suggest that grain size-dependent analyses of D-SARs and D-SIRs may help to disentangle the mechanisms that generate SARs and SIRs and may enable early detection of the effects of fragmentation on plant biodiversity. © 2014 John Wiley & Sons Ltd.

AB - Aim: Patterns that relate species richness with fragment area (the species-area relationship, SAR) and with isolation (the species-isolation relationship, SIR) are well documented. However, those that relate species density - the number of species within a standardized area - with fragment area (D-SAR) or isolation (D-SIR) have not been sufficiently explored, despite the potential for such an analysis to disentangle the underlying mechanisms of SARs and SIRs. Previous spatial theory predicts that a significant D-SAR or D-SIR is unlikely to emerge in taxa with high dispersal limitation, such as plants. Furthermore, a recent model predicts that the detection and the significance of D-SARs or D-SIRs may decrease with grain size. We combined a literature review with grain size-dependent sampling in a fragmented landscape to evaluate the prevalence and grain size-dependent nature of D-SARs and D-SIRs in plants. Location: Worldwide (review) and a semi-arid agro-ecosystem in Israel (case study). Methods: We combined an extensive literature review of 31 D-SAR studies of plants in fragmented landscapes with an empirical study in which we analysed grain size-dependent D-SARs and D-SIRs using a grain size-dependent hierarchical sampling of species density and species richness in a fragmented, semi-arid agro-ecosystem. Results: We found that significantly increasing D-SARs are rare in plant studies. Furthermore, we found that the detection of a significant D-SAR is often possible only after the data have been stratified by species, habitat or landscape characteristics. The results from our case study indicated that the significance and the slopes of both D-SARs and D-SIRs increase as grain size decreases. Main conclusions: These results call for a careful consideration of scale while analysing and interpreting the responses of species richness and species density to fragmentation. Our results suggest that grain size-dependent analyses of D-SARs and D-SIRs may help to disentangle the mechanisms that generate SARs and SIRs and may enable early detection of the effects of fragmentation on plant biodiversity. © 2014 John Wiley & Sons Ltd.

KW - Ecosystems Research

KW - Conservation biogeography

KW - extinction debt

KW - habitat fragmentation

KW - habitat islands

KW - island biogeography theory

KW - island ecology

KW - isolation

KW - scale-dependence

KW - species–area relationship

KW - species density

UR - http://www.scopus.com/inward/record.url?scp=84900441101&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/cad677e4-33a2-3ead-a7f1-d5dd9866a77b/

U2 - 10.1111/jbi.12299

DO - 10.1111/jbi.12299

M3 - Journal articles

VL - 41

SP - 1055

EP - 1069

JO - Journal of Biogeography

JF - Journal of Biogeography

SN - 0305-0270

IS - 6

ER -