A past–present–future lens of environmental change: blending applied paleoecology and participatory system dynamics modeling at a conservation site in the Cape Floristic Region, South Africa

Abstract

Landscapes are social–ecological systems (SESs) that produce ecosystem services, which change over time in response to environmental, biotic, and social drivers. Failure to consider this variability, and the feedbacks that can stabilize or destabilize systems, can have consequences for sustainable ecosystem services provision. This study applies a conceptual meta-framework, past–present–future lens, to interpret changes in land cover and ecosystem services within the Cape Floristic Region (CFR) of South Africa. Paleoecology (fossil pollen, spores, and charcoal) and participatory system dynamics modeling were used to explore long-term variability in provisioning ecosystem services (plant biodiversity) and the drivers of this variability (fire and herbivory) at Elandsberg Private Nature Reserve (Elandsberg PNR). From ca. 1800s, the paleoecological record suggests that environmental changes, particularly a transition to unpalatable Elytropappus-dominated vegetation, were driven by grazing and that an ecological threshold was crossed in ca. 1950s due to agricultural intensification. Participatory system dynamics was used to identify feedbacks in the dynamic SES structure. The ecological model replicates the paleoecological results and, furthermore, suggests that in the future, returning the system to within historical ranges variability may require sustained reductions in both grazing and fire over decades. This innovative approach blends paleoecology and participatory system dynamics to provide an evidence-based understanding of temporal variability and feedbacks for policymakers and land-use managers to inform sustainable land management.