Grand challenges in biodiversity-ecosystem functioning research in the era of science-policy platforms require explicit consideration of feedbacks

Abstract

Feedbacks are an essential feature of resilient socio-economic systems, yet the feedbacks between biodiversity, ecosystem services and human wellbeing are not fully accounted for in global policy efforts that consider future scenarios for human activities and their consequences for nature. Failure to integrate feedbacks in our knowledge frameworks exacerbates uncertainty in future projections and potentially prevents us from realizing the full benefits of actions we can take to enhance sustainability. We identify six scientific research challenges that, if addressed, could allow future policy, conservation and monitoring efforts to quantitatively account for ecosystem and societal consequences of biodiversity change. Placing feedbacks prominently in our frameworks would lead to (i) coordinated observation of biodiversity change, ecosystem functions and human actions, (ii) joint experiment and observation programmes, (iii) more effective use of emerging technologies in biodiversity science and policy, and (iv) a more inclusive and integrated global community of biodiversity observers. To meet these challenges, we outline a five-point action plan for collaboration and connection among scientists and policymakers that emphasizes diversity, inclusion and open access. Efforts to protect biodiversity require the best possible scientific understanding of human activities, biodiversity trends, ecosystem functions and-critically-the feedbacks among them.

Keywords: biodiversity; ecosystem functioning; feedbacks; grand challenges; science–policy; socioecological systems.

Figure 1.

Direct effects, indirect effects and feedbacks in the biodiversity–ecosystem functioning–human wellbeing (B-E-H) system. (a) Direct effects are one-way effects of, for example, species richness on an ecosystem function; biodiversity–ecosystem functioning (BEF) research has emphasized the direct effect of diversity on functioning (dashed arrow). (b) Indirect effects are summed direct effects. (c) Feedbacks are iterative and ongoing, often looping, effects of system components on each other. (d) In an aquatic example, invertebrate and vertebrate diversity enhance ecosystem functions such as biomass production that may be harvested for food and livelihood by people. Harvesting may maintain some fish at high population growth rates by reducing population densities thereby maintaining biodiversity; (e) in an agricultural plant–pollinator system, a full feedback between diversity, plant seed production and human activities has led to recognition that conservation measures to protect pollinator diversity may benefit humans by enhancing crop yields.

Figure 2.

Feedbacks in (a,b) population dynamics and (c) community dynamics. (a) Positive and (b) negative feedback between population growth rate (dN/dt) and population density (N_t) in closed systems comprising one population. (c) Density-dependent feedbacks among plant populations and species can lead to a positive effect of plant diversity on plant productivity (an ecosystem function). Nutrient supply can modify the relationship between diversity and productivity by directly enhancing productivity and by changing plant diversity and composition. Whether there is a feedback between nutrient supply, diversity and productivity is not yet fully resolved (the grey question mark).

Figure 3.

Models, experiments and observation systems are needed that explicitly address feedbacks and scales of space, time and biological organization. (a) Many programmes tend to focus in one part of this space—for example, generating data within the dashed box—and we argue for approaches that relate observations at multiple (modified from Gonzalez et al. [22]). (b) Hypothetical data copied from (a), illustrating that we should strive for observations and understanding of how biodiversity, human activities and ecosystem functions change at the same levels of spatial and temporal resolution, in the context of other spatial and temporal processes (a). (Online version in colour.)