No abstract

Classical epidemic theory focuses on directly transmitted pathogens, but many pathogens are instead transmitted when hosts encounter infectious particles. Theory has shown that for such diseases pathogen persistence time in the environment can strongly affect disease dynamics, but estimates of persistence time, and consequently tests of the theory, are extremely rare. We consider the consequences of persistence time for the dynamics of the gypsy moth baculovirus, a pathogen transmitted when larvae consume foliage contaminated with particles released from infectious cadavers. Using field-transmission experiments, we are able to estimate persistence time under natural conditions, and inserting our estimates into a standard epidemic model suggests that epidemics are often terminated by a combination of pupation and burnout, rather than by burnout alone as predicted by theory. Extending our models to allow for multiple generations, and including environmental transmission over the winter, suggests that the virus may survive over the long term even in the absence of complex persistence mechanisms, such as environmental reservoirs or covert infections. Our work suggests that estimates of persistence times can lead to a deeper understanding of environmentally transmitted pathogens, and illustrates the usefulness of experiments that are closely tied to mathematical models.

Marine social–ecological systems are constantly changing, and fishers who make a living from working the seas are continually adapting in response to different sources of variability. One main way in which fishers can adapt to ecosystem change is to change the fisheries they participate in. This acts to connect fisheries, creating interlinked networks of alternative sources of income for fishers. Here, we synthesize fisheries data and construct fisheries connectivity networks for all major ports in the US California Current Large Marine Ecosystem. Fisheries connectivity networks are comprised of nodes, which are fisheries, connected by edges, whose weights are proportional to the number of participating vessels. Fisheries connectivity networks identify central fisheries in the US California Current Large Marine Ecosystem, specifically Dungeness crab and Spiny Lobster, and systematic topological differences, e.g. in network resilience and modularity. These network metrics directly relate to the social vulnerability of coastal fishing communities, especially their sensitivity and capacity to adapt to perturbation. Ultimately, improving knowledge of fisheries connectivity is vital if policy makers are to create governance institutions that allow fishermen to adapt to environmental, technological and management change while at the same time enhancing the social and economic value of fisheries. In doing so, new policies that account for fisheries connectivity, will lead to improved sustainable fisheries management, and enhanced socioeconomic resilience of coastal communities.

In this period of environmental change, understanding how resource users respond to such changes is critical for effective resource management and adaptation planning. Extensive work has focused on natural resource responses to environmental changes, but less has examined the response of resource users to such changes. We used an interdisciplinary approach to analyse changes in resource use among commercial trawl fishing communities in the northwest Atlantic, a region that has shown poleward shifts in harvested fish species. We found substantial community-level changes in fishing patterns since 1996: southern trawl fleets of larger vessels with low catch diversity fished up to 400 km further north, while trawl fleets of smaller vessels with low catch diversity shrank or disappeared from the data set over time. In contrast, trawl fleets (of both large and small vessels) with higher catch diversity neither changed fishing location dramatically or nor disappeared as often from the data set. This analysis suggests that catch diversity and high mobility may buffer fishing communities from effects of environmental change. Particularly in times of rapid and uncertain change, constructing diverse portfolios and allowing for fleet mobility may represent effective adaptation strategies.

Human activity is dramatically shaping all of Earth's natural systems, producing unprecedented challenges for people and nature. Climate disruption, altered hydrology, and ecosystem degradation reflect both threats to human wellbeing and changes in the 'rules of the game' that make management difficult. While ecologists, conservationists and environmental scientists clamor for radical action to reverse these threats, their own management actions in response to climate are too often business as usual. I hypothesize that restrictive and often unspoken mental models of ecological and environmental science are robbing these managers and their institutions of the flexibility required to respond to the Anthropocene's uncertain changes. The three most profound mental traps are: (1) an undue emphasis on historical reference points; (2) an ecological concept of resilience that fails to reckon with the Anthropocene's dynamism; and (3) a precautionary bias against new technologies and dramatic interventions. Caught in these mental traps, environmentalists too often reject entrepreneurial experimental approaches that could make them more relevant to policymakers, corporations and other institutions that seek to respond more proactively to impending disruption. Policy Implications• All resource management objectives or targets that place a heavy reliance on maintaining historical conditions should be re-evaluated in light of climate disruption and other directional environmental trends.• Management mandates should have clear guidelines on triage so that resources are not expended in efforts that are made futile by massive anthropogenic change.• The precautionary principle should be rethought in light of our inability to guarantee the safety of any new technology, but the need for the benefits of new technology.• NGOs and government agencies should consider interventions that proactively assist change and assist biological evolution.• Because uncertainty about change is huge, and idiosyncratic to local contingencies, regulatory frameworks or government incentives must find ways to allow flexible responses, and learn through networks of responders as opposed to following top-down recipes.Most resource management practice and conservation policy was established before there was widespread awareness of the unprecedented pace and magnitude of environmental change caused by humans. In this article one asks to what extent major conservation practices have adjusted in response to rapid environmental change, as well as examine empirical data on the responses of ecosystems to massive perturbations. The purpose of examining perturbations is to determine whether ecosystems generally recover from perturbations, because the answer to that question should influence what are set as policy objectives when natural systems are managed. In addition to examining conventional management practices and data on environmental catastrophes, the broader conceptual framings for environmental policy such as the precautionary principle are conside...