Vegetation Dynamics as a Proxy of Socio-ecological Transitions and Future Societal Benefits in Mountain PAs
Lead Author: João Honrado et al. (InBIO/ICETA team)
Many mountain areas across Europe are undergoing rapid socio-ecological transitions, following the decline of traditional land management systems. Extensive land abandonment reflects the decline in importance of provisioning services from local ecosystems, due to external inputs and demographic changes, and generally increases vulnerability to wildfires, invasive species and other hazardous events. In parallel with this socio-ecological shift, many of these areas have been designated for nature protection under various policy instruments. International (EU) initiatives, mainly related to rural development and agricultural policy (CAP), have tried to mitigate rural abandonment through financial mechanisms aimed to compensate for the strong constraints to farming in marginal mountain areas. In spite of the strong limitations of data for detailed assessment, there is a wide agreement on the limited success of those initiatives so far, even if the rate of abandonment has locally been slowed. In parallel, a strong movement towards controlled rewilding of mountain areas (through either passive or active management of ecological processes) has been built upon two main ideas: maintaining competitive farming systems in marginal land is a paramount challenge in a globalized economy; and rewilding is due to foster nature conservation as well as the provision of other valuable benefits to the wider society.
The widespread decrease in land management for provision of goods triggers succession, changing vegetation cover and landscape heterogeneity at a rate dependent on local resilience. In mountain areas under Mediterranean-type of climate, abandonment is often related with important changes in local fire regimes. On the one hand, the historical use of fire as a land management tool strongly declines, especially when a decrease of husbandry occurs. On the other hand, the accumulation and increased connectivity of plant biomass (often dominated by fire-prone shrubs) profoundly changes fire behaviour. These two factors together have transformed fire regimes from “frequent, small, and low intensity/severity fires” into “less frequent but large and intense/severe fires”. Moreover, this fire-vegetation dynamics interacts with two other global change processes: climate change, and invasion by non-native (often fire-prone) plants. This complex interaction will have profound effects on the pathways of vegetation dynamics, potentially compromising the supply of valuable benefits from mountain PAs and challenging passive rewilding as a land management strategy.
This storyline builds on the hypothesis that the socio-ecological transitions described above have been joined by a shift in the primary societal expectations from mountain areas; more specifically, that these expectations are nowadays mainly related to two groups of benefits: conservation of natural heritage, and supply of regulating and cultural ecosystem services. The supply of benefits from these two groups can be severely impacted by the condition and dynamics of vegetation cover, which is therefore seen as a promising proxy to inform on the state and trends of those benefits. A pilot implementation of the storyline will be done in the Peneda-Gerês National Park (Portugal), where the decline of the traditional agro-pastoral system of upland areas has enabled widespread scrub encroachment and produced changes in fire regimes, which may be aggravated under future climates. Selected benefits from the two above groups will be modelled against four main drivers: land use (change), climate (change), fire regime, and invasion by non-native plants. Models will be forced with various socio-ecological scenarios related to the main drivers, and trade-off analyses will be implemented to identify ‘win-win’ solutions for the focal benefits.