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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...

The seascapes on which many millions of people make their living and secure food have complex and dynamic spatial features-the figurative hills and valleys-that influence where and how people work at sea. Here, we quantify the physical mosaic of the surface ocean by identifying Lagrangian Coherent Structures for a whole seascape-the U.S. California Current Large Marine Ecosystem-and assess their impact on the spatial distribution of fishing. We observe that there is a mixed response: some fisheries track these physical features, and others avoid them. These spatial behaviors map to economic impacts, in particular we find that tuna fishermen can expect to make three times more revenue per trip if fishing occurs on strong Lagrangian Coherent Structures. However, we find no relationship for salmon and pink shrimp fishing trips. These results highlight a connection between the biophysical state of the oceans, the spatial patterns of human activity, and ultimately the economic welfare of coastal communities.

Fishers worldwide operate in an environment of uncertainty and constant change. Their ability to manage risk associated with such uncertainty and subsequently adapt to change is largely a function of individual circumstances, including their access to different fisheries. However, explicit attention to the heterogeneity of fishers’ connections to fisheries at the level of the individual has been largely ignored. We illustrate the ubiquitous nature of these connections by constructing a typology of commercial fishers in the state of Maine based on the different fisheries that fishers rely on to sustain their livelihoods and find that there are over 600 combinations. We evaluate the adaptive potential of each strategy, using a set of attributes identified by fisheries experts in the state, and find that only 12% of fishers can be classified as being well positioned to adapt in the face of changing socioeconomic and ecological conditions. Sensitivity to the uneven and heterogeneous capacity of fishers to manage risk and adapt to change is critical to devising effective management strategies that broadly support fishers. This will require greater attention to the social-ecological connectivity of fishers across different jurisdictions.

Subsistence hunting presents a conservation challenge by which biodiversity preservation must be balanced with safeguarding of human livelihoods. Globally, subsistence hunting threatens primate populations, including Madagascar's endemic lemurs. We used population viability analysis to assess the sustainability of lemur hunting in Makira Natural Park, Madagascar. We identified trends in seasonal hunting of 11 Makira lemur species from household interview data, estimated local lemur densities in populations adjacent to focal villages via transect surveys, and quantified extinction vulnerability for these populations based on species-specific demographic parameters and empirically derived hunting rates. We compared stage-based Lefkovitch with periodic Leslie matrices to evaluate the impact of regional dispersal on persistence trajectories and explored the consequences of perturbations to the timing of peak hunting relative to the lemur birth pulse, under assumptions of density-dependent reproductive compensation. Lemur hunting peaked during the fruit-abundant wet season (March-June). Estimated local lemur densities were roughly inverse to body size across our study area. Life-history modeling indicated that hunting most severely threatened the species with the largest bodies (i.e., Hapalemur occidentalis, Avahi laniger, Daubentonia madagascariensis, and Indri indi), characterized by late-age reproductive onsets and long interbirth intervals. In model simulations, lemur dispersal within a regional metapopulation buffered extinction threats when a majority of local sites supported growth rates above the replacement level but drove regional extirpations when most local sites were overharvested. Hunt simulations were most detrimental when timed to overlap lemur births (a reality for D. madagascariensis and I. indri). In sum, Makira lemurs were overharvested. Regional extirpations, which may contribute to broad-scale extinctions, will be likely if current hunting rates persist. Cessation of anthropogenic lemur harvest is a conservation priority, and development programs are needed to help communities switch from wildlife consumption to domestic protein alternatives.