Search for: All records

Abstract Causal effects of biodiversity on ecosystem functions can be estimated using experimental or observational designs — designs that pose a tradeoff between drawing credible causal inferences from correlations and drawing generalizable inferences. Here, we develop a design that reduces this tradeoff and revisits the question of how plant species diversity affects productivity. Our design leverages longitudinal data from 43 grasslands in 11 countries and approaches borrowed from fields outside of ecology to draw causal inferences from observational data. Contrary to many prior studies, we estimate that increases in plot-level species richness caused productivity to decline: a 10% increase in richness decreased productivity by 2.4%, 95% CI [−4.1, −0.74]. This contradiction stems from two sources. First, prior observational studies incompletely control for confounding factors. Second, most experiments plant fewer rare and non-native species than exist in nature. Although increases in native, dominant species increased productivity, increases in rare and non-native species decreased productivity, making the average effect negative in our study. By reducing the tradeoff between experimental and observational designs, our study demonstrates how observational studies can complement prior ecological experiments and inform future ones. 

This article shows the two‐way relation between global norms and local conditions as they shape Payments for Ecosystem Services (PES) theory and practice, through a case study of a water fund in Valle del Cauca, Colombia, the heartland of the country's sugarcane industry. Drawing on interviews, survey data and historical research, the article argues that the water fund should be understood in the context of the history of infrastructure for the sugarcane industry in the region, and that this infrastructural perspective provides a more nuanced insight into the fund's political life than the traditional PES framing. Furthermore, the article shows how the norms embedded in this locally grown programme circulated through international networks to influence PES theory and design. This case offers one example of the need to attend to the multiple and geographically specific histories of actually existing PES in order to understand its diversity in the present.

 

Nature‐based solutions (NBS) are an increasingly popular approach to water resources management, with a growing number of projects designed to take advantage of landscape effects on water flow. As NBS for water are developed, producing hydrologic information to inform decisions often requires substantial investment in data acquisition and modeling; for this effort to be worthwhile, the information generated must be useful and used. We apply an evaluation framework of salience (type of information), credibility (quality of information), and legitimacy (trustworthiness of information) to assess how hydrologic modeling outputs have been used in NBS projects by three types of decision makers: advocates, implementers, and analysts. Our findings, based on documents and interviews with watershed management programs in South America currently implementing NBS, consider how hydrologic modeling supports two types of decisions for NBS projects: quantifying the hydrologic impact of potential and existing NBS and prioritizing where NBS might be sited within a watershed. To help inform future modeling studies, we identify several problematic assumptions that analysts may make about the credibility of modeled outputs for NBS when advocates and implementers are not effectively engaged. We find that salient, credible, and legitimate results in applications evaluating NBS for water are not always generated in the absence of clear communication and engagement. Integr Environ Assess Manag2022;18:135–147. © 2021 The Authors.Integrated Environmental Assessment and Managementpublished by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC).