Browsing by Subject "ecosystem health"

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    Biodiversity increases the resistance of ecosystem productivity to climate extremes
    (Nature Publishing Group, 2015) Isbell, Forest; Craven, Dylan; Connolly, John; Loreau, Michel; Schmid, Bernhard; Beierkuhnlein, Carl; Bezemer, T. Martijn; Bonin, Catherine; Bruelheide, Helge; de Luca, Enrica; Ebeling, Anne; Griffin, John N; Guo, Qinfeng; Hautier, Yann; Hector, Andy; Jentsch, Anke; Kreyling, Jürgen; Lanta, Vojtěch; Manning, Pete; Meyer, Sebastian T; Mori, Akira S.; Naeem, Shahid; Niklaus, Pascal A; Polley, H. Wayne; Reich, Peter B; Roscher, Christiane; Seabloom, Eric W; Smith, Melinda D; Thakur, Madhav P; Tilman, David; Tracy, Benjamin F; van der Putten, Wim H; van Ruijven, Jasper; Weigelt, Alexandra; Weisser, Wolfgang W; Wilsey, Brian; Eisenhauer, Nico
    It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, whereas that of high-diversity communities with 16-32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high- and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events.
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    Developing an ecosystem health approach for reducing risk of fish pathogen introduction in a coupled social-ecological system
    (2022-05) McEachran , Margaret
    Today’s interconnected society provides ample opportunity for the inadvertent spread of dangerous diseases. Human activities are also capable of spreading wildlife diseases that can have devastating impacts on populations and threaten biodiversity. In inland fisheries, the use and release of live baitfish by recreational anglers has been identified as a particularly important pathway for the spread of pathogens. Despite regulations prohibiting it, baitfish release is widespread and common among anglers, providing substantial opportunity for pathogen spread via this pathway. To address key knowledge gaps and understand the social and ecological dimensions of risk of pathogen spread, I developed an ecosystem health approach to identify, quantify, and mitigate the risk of fish pathogen introduction via the release of live baitfish in Minnesota, USA. I first created a hazard prioritization method to identify the pathogens most likely to harm important Minnesota fishes via release of live baitfish. To quantify the risk of one of these pathogens being released into Minnesota waters, I implemented a survey of adult anglers and used this data to parameterize a stochastic risk assessment model. I modelled pathogen introduction risk across a variety of scenarios representing baseline, outbreak, and source-control scenarios. I found that the average number of angling trips resulting in pathogen release was high across all modeled scenarios, ranging from fewer than 10,000 in a small, localized outbreak, to 1.2 million in a statewide outbreak in multiple live baitfish species. Additionally, I found reducing the rate of illegal release could offer meaningful risk reduction in some scenarios with high pathogen prevalence and/or broad pathogen distribution, but this effect was less pronounced in scenarios where the outbreak was geospatially or otherwise limited. Finally, I used the Theory of Planned Behavior to identify the social and psychological determinants of baitfish release behavior and found that knowledge of the existing regulatory framework and subjective norms around live baitfish disposal play an important role in deterring illegal release. In these four chapters, I demonstrate the implementation of an integrated social-ecological approach to a complex ecosystem health issue and provide a roadmap for managing the risk of fish pathogen introduction via live baitfish release in Minnesota.