Government policies are needed when people's behaviors fail to deliver the public good. Those policies will be most effective if they can stimulate long-term changes in beliefs and norms, creating and reinforcing the behaviors needed to solidify and extend the public good. It is often the short-term acceptability of potential policies, rather than their longer-term efficacy, that determines their scope and deployment. The policy process should include a consideration of both timescales. The academy, however, has provided insufficient insight on the coevolution of social norms and different policy instruments, thus compromising the ability of decisionmakers to craft effective solutions to the society's most intractable environmental problems. Life scientists could make fundamental contributions to this agenda through targeted research on the emergence of social norms.

Habitat connectivity is vital to the persistence of migratory fishes. Native tropical island stream fish assemblages composed of diadromous species require intact corridors between ocean and riverine habitats. High dams block fish migration, but low-head artificial barriers are more widespread and are rarely assessed for impacts. Among all 46 drainages in Puerto Rico, we identified and surveyed 335 artificial barriers that hinder fish migration to 74.5% of the upstream habitat. We also surveyed occupancy of native diadromous fishes (Anguillidae, Eleotridae, Gobiidae, and Mugilidae) in 118 river reaches. Occupancy models demonstrated that barriers 2 meters (m) high restricted nongoby fish migration and extirpated those fish upstream of 4-m barriers. Gobies are adapted to climbing and are restricted by 12-m barriers and extirpated upstream of 32-m barriers. Our findings quantitatively illustrate the extensive impact of low-head structures on island stream fauna and provide guidance for natural resource management, habitat restoration, and water development strategies.

Allometries and scaling relationships have become popular among biologists. One reason for this popularity is the generality of these relationships, which has provided authors hope that allometries and scaling relationships represent biological laws or explanatory generalizations. In this article, I discuss three roles of allometries and scaling relationships: the explanatory, the predictive, and the heuristic. I argue that allometries and scaling relationships often function successfully heuristically—that is, discovering or elucidating patterns from data rather than making accurate predictions or giving illuminating explanations. The heuristic role is not to be overlooked. A science or discipline without interesting objects of explanation lacks the potential to progress and mature.

Winter is a critical period for aquatic organisms; however, little is known about the ecological significance of its extreme events. Here, we link winter ecology and disturbance research by synthesizing the impacts of extreme winter conditions on riverine habitats and fish assemblages in temperate and cold regions. We characterize winter disturbances by their temporal pattern and abiotic effects, explore how various drivers influence fish, and discuss human alterations of winter disturbances and future research needs. We conclude that (a) more data on winter dynamics are needed to identify extreme events, (b) winter ecology and disturbance research should test assumptions of practical relevance for both disciplines, (c) hydraulic and population models should incorporate winter- and disturbance-specific aspects, and (d) management for sustainability requires that river managers work proactively by including anticipated future alterations in the design of restoration and conservation activities.

The areas targeted for restoration are often the modified ecosystems that are rapidly becoming the planetary norm, and when ecosystem modification has been extensive, local genotypes may not be the most effective for repair. Here, local has value is presented as a paradigm for the restoration of such systems as a corollary to local is best for systems that have sustained less modification. In many cases, adaptation may be enhanced through genetic variation or applying artificial selection, particularly for generalist species. Ecologically appropriate plant materials are those that exhibit ecological fitness for their intended site, display compatibility with other members of the plant community, and demonstrate no invasive tendencies. They may address specific environmental challenges, rejuvenate ecosystem function, and improve the delivery of ecosystem services. Furthermore, they may be improved over time, thereby serving to ameliorate the increasingly challenging environments that typify many restoration sites.