Accidental experiments: ecological and evolutionary insights and opportunities derived from global change

Abstract

Humans are the dominant ecological and evolutionary force on the planet today, transforming habitats, polluting environments, changing climates, introducing new species, and causing other species to decline in number or go extinct. Th ese worrying anthropogenic impacts, collectively termed global change, are often viewed as a confounding factor to minimize in basic studies and a problem to resolve or quantify in applied studies. However, these ' accidental experiments ' also represent opportunities to gain fundamental insight into ecological and evolutionary processes, especially when they result in perturbations that are large or long in duration and diffi cult or unethical to impose experimentally. We demonstrate this by describing important fundamental insights already gained from studies which utilize global change factors as accidental experiments. In doing so, we highlight why accidental experiments are sometimes more likely to yield insights than traditional approaches. Next, we argue that emerging environmental problems can provide even more opportunities for scientifi c discovery in the future, and provide both examples and guidelines for moving forward. We recommend 1) a greater fl ow of information between basic and applied subfi elds of ecology and evolution to identify emerging opportunities; 2) considering the advantages of the ' accidental experiment ' approach relative to more traditional approaches; and 3) planning for the challenges inherent to uncontrolled accidental experiments. We emphasize that we do not view the accidental experiments provided by global change as replacements for scientifi c studies quantifying the magnitude of anthropogenic impacts or outlining strategies for mitigating impacts. Instead, we believe that accidental experiments are uniquely situated to provide insights into evolutionary and ecological processes that ultimately allow us to better predict and manage change on our human-dominated planet.

Climate drives phenological reassembly of a mountain wildflower meadow community

“…Thus, despite its limitations, we believe that this natural experiment provides unique insight into the magnitude, spatial pattern, and drivers of phenological reassembly in this system driven by variation in climate (Diamond , HilleRisLambers et al. ).…”

Consequences of Seed Dispersal for Plant Recruitment in Tropical Forests: Interactions Within the Seedscape

“…Accidental experiments in which intact forests are compared to forests experiencing human disturbances, such as logging, fragmentation, hunting, or invasive species, are increasingly common, and have the advantage of examining the effect of dispersal at temporal and spatial scales that are infeasible in manipulative experiments (Diamond , Sagarin & Pauchard , HilleRisLambers et al . ).…”

Changes in the background losses of woody plant foliage to insects during the past 60 years: are the predictions fulfilled?

“…Although causal relationships cannot be inferred from the negative correlation found between the year of data collection and herbivory in the tropics, the long-term temporal trends in characteristics of biota are usually associated with changes in temperature and precipitation during the observation period [19]-assuming that a plausible explanation of the mechanisms behind the detected changes is provided. We attribute the decrease in foliar losses of tropical woody plants to insects to adverse effects of increasing temperature, because both consumption rates and fitness of herbivorous insects (which are ectothermic organisms) decline sharply once a species encounters temperatures beyond its thermal optimum [20].…”