Relationships between amount and configuration indicators in real-world landscapes: Novel references for the assessment of forest cover in the Iberian Peninsula

Abstract

Understanding the role of habitat loss and fragmentation per se is crucial to generate relevant knowledge for habitat management. In the case of forest species, this can be achieved by measuring forest amount and configuration metrics at the landscape scale, including their relationship. We aimed to characterize the relationship between forest amount and configuration metrics in real-world landscapes of an extensive area, identifying forest amount thresholds that discriminate among forest fragmentation levels. We also investigated whether ecological and political contexts could affect the strength of the relationship. We comprehensively analyzed forest cover in the Iberian Peninsula (20.56 million ha, year 2,018). We calculated Forest Area Density (FAD) and three configuration metrics by employing a moving-window procedure. From metrics’ surfaces we derived bivariate probability-density scatterplots, a synoptic Fragmentation Level indicator (FL) and subsequent classification and correlation analyses. For Number of Patches and Edge Density (ED) maximum values and variability appeared at FAD 20% and 50%, respectively. The extreme FAD thresholds relative to FL were 89% and 55%, potentially representing fragmentation and extinction thresholds for a generic forest species. Major differences between Portugal and Spain were found in ED in the Mediterranean Ecoregions, being wildfire regimes and ownership patterns plausible explanations. We provide insights into the patterns of forest cover and metrics’ references valuable to identify areas of concern for management and conservation in the region, as well as a foundation for further research on the ecological responses to forest fragmentation.

Keywords

• Forest pattern
• Forest fragmentation
• FAD
• Landscape metric surface
• Geographic information systems
• Mediterranean forests