An ecological Indicator framework for conservation status assessment: promoting the sustainability of natural remnant habitats in the Montado agroecosystem

Abstract

Natural Remnant Habitats (NRHs) are native natural landscape elements that persist within agroecosystem landscapes and provide ecosystem goods and services, contributing significantly to landscape heterogeneity and high biodiversity. However, these habitats patches are increasingly threatened by both agricultural intensification and land abandonment, making the characterization and assessment of their Conservation Status (CS) essential to their effective conservation. With this study we aimed to develop a field-based, multi-criteria ecological indicator framework for the practical assessment of the CS of NRHs within the Montado, a High Nature Value agroecosystem. We conducted fieldwork in Alentejo (Portugal) over three spring seasons where we sampled 226 NRHs, representing six NRH types—Forest and Shrub Patches, Rocky Outcrops, Riparian Galleries, Temporary and Permanent Ponds. We recorded several biophysical parameters based on their expected relevance as potential CS indicators. We used two complementary CS assessments approaches — expert-based and field indicator-based—to identify NRH patches with excellent CS and to select indicators that effectively discriminate among groups distributed along a continuum of CS conditions. We then compared these approaches to validate the framework. Our results show that CS assessment varies strongly among NRH types, and that no universal set of indicators is suitable. Although the proposed framework still requires further refinement, it provides a practical tool for translating ecological complexity into an operational CS assessment based on NRH-specific and easily observable field indicators, thus reducing the need for specialized expertise. It enables clear discrimination between the most contrasting CS (excellent vs poor) and supports evidence-based conservation, land management, and policy development in Mediterranean farming landscapes.