Integrating landscape disturbance and indicator species in conservation studies

PLoS One. 2013 May 1;8(5):e63294. doi: 10.1371/journal.pone.0063294. Print 2013.

Abstract

Successful conservation plans are conditioned by our ability to detect anthropogenic change in space and time and various statistical analyses have been developed to handle this critical issue. The main objective of this paper is to illustrate a new approach for spatial analysis in conservation biology. Here, we propose a two-step protocol. First, we introduce a new disturbance metric which provides a continuous measure of disturbance for any focal communities on the basis of the surrounding landscape matrix. Second, we use this new gradient to estimate species and community disturbance thresholds by implementing a recently developed method called Threshold Indicator Taxa ANalysis (TITAN). TITAN detects changes in species distributions along environmental gradients using indicators species analysis and assesses synchrony among species change points as evidence for community thresholds. We demonstrate our method with soil arthropod assemblages along a disturbance gradient in Terceira Island (Azores, Portugal). We show that our new disturbance metric realistically reflects disturbance patterns, especially in buffer zones (ecotones) between land use categories. By estimating species disturbance thresholds with TITAN along the disturbance gradient in Terceira, we show that species significantly associated with low disturbance differ from those associated with high disturbance in their biogeographical origin (endemics, non-endemic natives and exotics) and taxonomy (order). Finally, we suggest that mapping the disturbance community thresholds may reveal areas of primary interest for conservation, since these may host indigenous species sensitive to high disturbance levels. This new framework may be useful when: (1) both local and regional processes are to be reflected on single disturbance measures; (2) these are better quantified in a continuous gradient; (3) mapping disturbance of large regions using fine scales is necessary; (4) indicator species for disturbance are searched for and; (5) community thresholds are useful to understand the global dynamics of habitats.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Distribution
  • Animals
  • Arthropods*
  • Azores
  • Biodiversity
  • Conservation of Natural Resources*
  • Data Interpretation, Statistical
  • Population Dynamics
  • Soil

Substances

  • Soil

Grants and funding

Data used in this manuscript were obtained in the projects funded by Direcção Regional dos Recursos Florestais (Project: 17.01-080203, 1999–2004) and Direcção Regional da Ciência e Tecnologia (Project: “Consequences of land-use change on Azorean fauna and flora - the 2010 Target”, M.2.1.2/I/003/2008). Grants and fellowships to the authors were provided by Fundação Ciência e Tecnologia (SFRH/BPD/40688/2007 and PTDC/BIA-BEC/100182/2008 for PC and FR, respectively) and Azorean Biodiversity Group (CITA-A) (Summer 2010, 2011 and 2012 grants to SF). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.