Using biodiversity features to promote an Ecosystem-Based Conservation framework in terrestrial ecosystems

PLOS One | https://doi.org/10.1371/journal.pone.0336705 November 21, 2025 3 / 18 Ecosystem-based conservation has received considerable attention primarily through the Ecosystem-based Approach (EBA), established by the Convention on Biological Diversity [26,27]. The EBA is based on a framework that integrates the management of land, water, and living resources, recognising ecosystems as “dynamic complexes of plant, animal, and microorganism communities and their non-living environment interacting as a functional unit” [27]. However, EBA has rarely been operationalised for biodiversity assessment and planning. In this study, we propose an Ecosystem-Based Conservation (EBC) framework as a step forward on EBA, serving as an operational conservation strategy to increase conservation efforts beyond PAs. The EBC framework treats the ecosystems as social-ecological units, where native biota and human communities have co-evolved over time. These interactions have generated Traditional Ecological Knowledge (TEK), supporting coexistence and generating nature’s contributions to people through ecosystem service bundles [28]. In Tanzania, eight major terrestrial ecosystems exist, each with distinct biota and communities with unique TEK. These eco- systems and associated communities provide different opportunities for sustaining biodiversity conservation and provision of ecosystem services [29–31]. Unlike the PA approach, which confines conservation within boundaries, the EBC frame-

work promotes biodiversity conservation as well as incentives for stewardship beyond the boundaries of PAs. The frame- work, therefore, offers a more inclusive biodiversity conservation strategy outside protected areas and a complementary strategy for effective biodiversity conservation at ecosystem level. Understanding biodiversity features that are unique to a specific ecosystem and how people and biodiversity overlap and interact outside protected area networks is crucial for establishing realistic, sustainable targets for guiding biodiversity conservation and ecosystem service delivery beyond protected areas. However, how unprotected areas of ecosystems and communities can sustain or enhance ecosystem services through improved conservation requires novel frameworks such as EBC that can guide biodiversity conservation and sustainable management at the ecosystem level; thus, optimising conservation efforts and benefits beyond protected areas. Assessing biodiversity distribution across multiple ecosystems is crucial for informing ecosystem-based conservation strategies. Measuring and assessing aspects of biodiversity, even for well-studied taxa like birds and large mammals, however, remains challenging [32,33]; hence, biodiversity proxies are often used. In conservation science, biodiversity features such as species richness, indicator species, species-area curve, and biomass are commonly used proxies. Ecosystem services and bio-indicator species also help in the evaluation of ecosystem integrity [34,35]. In this study,

biodiversity features refer to a group taxon level (i.e., key taxonomic groups, including vertebrates, plants, and inverte- brates), that represent biological diversity within ecosystems. In many countries, including Tanzania, biodiversity data remain sparse and uneven, particularly outside protected areas and for less-studied taxa [36,37]. Literature-based data compilation is, therefore, a pragmatic method to estimate ecosystem-level biodiversity distribution [38]. We used the sum of reported biodiversity features in each of the three taxonomic groups as a proxy to estimate how biodiversity is distrib- uted across different terrestrial ecosystems in Tanzania. While such data are shaped by sampling and publication biases, they still provide critical insights into underrepresented taxa and overlooked ecosystems. This approach aligns with recent Kunming-Montreal Global Biodiversity Framework targets [6,39] of supporting inclusive spatial management (Target 1); restoring degraded ecosystems (Target 2); increasing green and blue spaces in urban areas (Target 12), as well as evidence-based conservation planning. Tanzania is a biodiversity-rich country that has expanded its PAs network, covering marine, terrestrial, and inland water areas, surpassing Global Biodiversity Framework Target 3 by protecting over 40% of its total area [40]. Despite these efforts, Tanzania, widely regarded as a key country for conservation in mainland Africa, is experiencing a rapid decline in biodiver-

sity [41–43]. This loss is undermining ecosystem resilience and diminishing nature’s capacity to support human well-being [44–46]. Consequently, this study has focused on Tanzania to assess and delineate (i) terrestrial ecosystems found in Tanza- nia, (ii) PAs and their proportions across different ecosystems; and (iii) distribution estimates of biodiversity features in each ecosystem, as a proxy for species richness. The resulting data provide a foundation for developing and promoting a new and effective EBC framework, as a complementary strategy to enhance biodiversity conservation beyond PA boundaries.