Multiple social network influences can generate unexpected environmental outcomes.

Understanding the function of social networks can make a critical contribution to achieving desirable environmental outcomes. Social-ecological systems are complex, adaptive systems in which environmental decision makers adapt to a changing social and ecological context. However, it remains unclear how multiple social influences interact with environmental feedbacks to generate environmental outcomes. Based on national-scale survey data and a social-ecological agent-based model in the context of voluntary private land conservation, our results suggest that social influences can operate synergistically or antagonistically, thereby enabling behaviors to spread by two or more mechanisms that amplify each other's effects. Furthermore, information through social networks may indirectly affect and respond to isolated individuals through environmental change. The interplay of social influences can, therefore, explain the success or failure of conservation outcomes emerging from collective behavior. To understand the capacity of social influence to generate environmental outcomes, social networks must not be seen as 'closed systems'; rather, the outcomes of environmental interventions depend on feedbacks between the environment and different components of the social system.

Biotic interactions drive ecosystem responses to exotic plant invaders.

Ecosystem process rates typically increase after plant invasion, but the extent to which this is driven by (i) changes in productivity, (ii) exotic species' traits, or (iii) novel (non-coevolved) biotic interactions has never been quantified. We created communities varying in exotic plant dominance, plant traits, soil biota, and invertebrate herbivores and measured indicators of carbon cycling. Interactions with soil biota and herbivores were the strongest drivers of exotic plant effects, particularly on measures of soil carbon turnover. Moreover, plant traits related to growth and nutrient acquisition explained differences in the ways that exotic plants interacted with novel biota compared with natives. We conclude that novel biological interactions with exotic species are a more important driver of ecosystem transformation than was previously recognized.

Biocultural Hysteresis Inhibits Adaptation to Environmental Change.

Indigenous peoples and local communities (IPLC) often use natural resources as both a reason and mechanism for environmental management, yet a number of environmental, social, and economic drivers disrupt this relationship. Here, we argue that these drivers can also trigger a set of feedback mechanisms that further diminish the efficacy of local management. We call this process biocultural hysteresis. These feedbacks, which include knowledge loss and a breakdown of social hierarchies, prevent IPLC from adapting their management to change. Biocultural hysteresis worsens as IPLC spend an increasing amount of time outside their social-ecological context. Therefore, we argue for adaptive policies and processes that favour protecting and enabling IPLC engagement with their environment.