80 research outputs found
Opportunities for behavioral rescue under rapid environmental change
Laboratory measurements of physiological and demographic tolerances are important in understanding the impact of climate change on species diversity; however, it has been recognized that forecasts based solely on these laboratory estimates overestimate risk by omitting the capacity for species to utilize microclimatic variation via behavioral adjustments in activity patterns or habitat choice. The complex, and often contextâdependent nature, of microclimate utilization has been an impediment to the advancement of general predictive models. Here, we overcome this impediment and estimate the potential impact of warming on the fitness of ectotherms using a benefit/cost tradeâoff derived from the simple and broadly documented thermal performance curve and a generalized cost function. Our framework reveals that, for certain environments, the cost of behavioral thermoregulation can be reduced as warming occurs, enabling behavioral buffering (e.g., the capacity for behavior to ameliorate detrimental impacts) and âbehavioral rescueâ from extinction in extreme cases. By applying our framework to operative temperature and physiological data collected at an extremely fine spatial scale in an African lizard, we show that new behavioral opportunities may emerge. Finally, we explore largeâscale geographic differences in the impact of behavior on climateâimpact projections using a global dataset of 38 insect species. These multiple lines of inference indicate that understanding the existing relationship between thermal characteristics (e.g., spatial configuration, spatial heterogeneity, and modal temperature) is essential for improving estimates of extinction risk
Assessing rabies vaccine protection against a novel lyssavirus, kotalahti bat lyssavirus
Rabies is a fatal encephalitis caused by an important group of viruses within the Lyssavirus genus. The prototype virus, rabies virus, is still the most commonly reported lyssavirus and causes approximately 59,000 human fatalities annually. The human and animal burden of the other lyssavirus species is undefined. The original reports for the novel lyssavirus, Kotalahti bat lyssavirus (KBLV), were based on the detection of viral RNA alone. In this report we describe the successful generation of a live recombinant virus, cSN-KBLV; where the full-length genome clone of RABV vaccine strain, SAD-B19, was constructed with the glycoprotein of KBLV. Subsequent in vitro characterisation of cSN-KBLV is described here. In addition, the ability of a human rabies vaccine to confer protective immunity in vivo following challenge with this recombinant virus was assessed. Naïve or vaccinated mice were infected intracerebrally with a dose of 100 focus-forming units/30 ”L of cSN-KBLV; all naïve mice and 8% (n = 1/12) of the vaccinated mice succumbed to the challenge, whilst 92% (n = 11/12) of the vaccinated mice survived to the end of the experiment. This report provides strong evidence for cross-neutralisation and cross-protection of cSN-KBLV using purified Vero cell rabies vaccine
Do Behavioral Foraging Responses of Prey to Predators Function Similarly in Restored and Pristine Foodwebs?
Efforts to restore top predators in human-altered systems raise the question of whether rebounds in predator populations are sufficient to restore pristine foodweb dynamics. Ocean ecosystems provide an ideal system to test this question. Removal of fishing in marine reserves often reverses declines in predator densities and size. However, whether this leads to restoration of key functional characteristics of foodwebs, especially prey foraging behavior, is unclear. The question of whether restored and pristine foodwebs function similarly is nonetheless critically important for management and restoration efforts. We explored this question in light of one important determinant of ecosystem function and structure â herbivorous prey foraging behavior. We compared these responses for two functionally distinct herbivorous prey fishes (the damselfish Plectroglyphidodon dickii and the parrotfish Chlorurus sordidus) within pairs of coral reefs in pristine and restored ecosystems in two regions of these species' biogeographic ranges, allowing us to quantify the magnitude and temporal scale of this key ecosystem variable's recovery. We demonstrate that restoration of top predator abundances also restored prey foraging excursion behaviors to a condition closely resembling those of a pristine ecosystem. Increased understanding of behavioral aspects of ecosystem change will greatly improve our ability to predict the cascading consequences of conservation tools aimed at ecological restoration, such as marine reserves
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Ontogenetic shifts in predator diet drive tradeoffs between fisheries yield and strength of predator-prey interactions
Evaluating potential artifacts of tethering techniques to estimate predation on sea urchins
6 pĂĄginas, 3 figuras,3 tablas.Measuring the strength of trophic interactions in marine systems has been central to our understanding of community
structuring. Sea urchin tethering has been the method of choice to evaluate rates of predation in marine
benthic ecosystems. As standardly practiced, this method involves piercing the urchin test, potentially introducing
significantmethodological artifacts thatmay influence survival or detection by predators.Herewe assess possible
artifacts of tethering comparing invasive (pierced) and non-invasive tethering techniques using the sea
urchin Paracentrotus lividus. Specifically, we looked at how degree of confinement and high water temperature
(first order artifacts) and predator guild and size of the prey (second order artifacts) affect the survival and/or detectability
of pierced urchins. Our results show that first order artifacts only arise when pierced sea urchins are
placed in sheltered bayswith confined waters, especiallywhenwater temperature reaches extremely high levels.
Prey detectability did not increase in pierced sea urchins for the most common predators. Also, test piercing did
not alter the preferences of predators for given prey sizes. Weconclude that the standard tethering technique is a
robust method to test relative rates of sea urchin predation. However, local conditions could increasemortality of
the tethered urchin in sheltered bays or in very high temperature regimes. Under these conditions, adequate
pierced controls (within predator exclusions) need to be included in assays to evaluate artifactual sources of
mortality.The Spanish Ministry of Science and Innovation (projects CTM2010-
22273-C02-01-02 and CTM2013-48027-C03-R) and the Spanish National
Research Council (project CSIC-201330E062) funded this research.
The Spanish Ministry of Science and Innovation supported J. B.
(scholarship BES-2011-043630).Peer reviewe
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Protection of large predators in a marine reserve alters size-dependent prey mortality.
Where predator-prey interactions are size-dependent, reductions in predator size owing to fishing has the potential to disrupt the ecological role of top predators in marine ecosystems. In southern California kelp forests, we investigated the size-dependence of the interaction between herbivorous sea urchins and one of their predators, California sheephead (Semicossyphus pulcher). Empirical tests examined how differences in predator size structure between reserve and fished areas affected size-specific urchin mortality. Sites inside marine reserves had greater sheephead size and biomass, while empirical feeding trials indicated that larger sheephead were required to successfully consume urchins of increasing test diameter. Evaluations of the selectivity of sheephead for two urchin species indicated that shorter-spined purple urchins were attacked more frequently and successfully than longer-spined red urchins of the same size class, particularly at the largest test diameters. As a result of these size-specific interactions and the higher biomass of large sheephead inside reserves, urchin mortality rates were three times higher inside the reserve for both species. In addition, urchin mortality rates decreased with urchin size, and very few large urchins were successfully consumed in fished areas. The truncation of sheephead size structure that commonly occurs owing to fishing will probably result in reductions in urchin mortality, which may reduce the resilience of kelp beds to urchin barren formation. By contrast, the recovery of predator size structure in marine reserves may restore this resilience, but may be delayed until fish grow to sizes capable of consuming larger urchins
Observed and modeled presence 1968-2014
NMFS Trawl Survey data used to fit species distribution models and the resulting modeled predictions for presence/absence (preds1) and abundance (preds)
Data from: Diversity in thermal affinity among key piscivores buffers impacts of ocean warming on predator-prey interactions
Asymmetries in responses to climate change have the potential to alter important predator-prey interactions, in part by altering the location and size of spatial refugia for prey. We evaluated the effect of ocean warming on interactions between four important piscivores and four of their prey in the U.S. Northeast Shelf by examining species overlap under historical conditions (1968-2014) and with a doubling in CO2. Because both predator and prey shift their distributions in response to changing ocean conditions, the net impact of warming or cooling on predator-prey interactions was not determined a priori from the range extent of either predator or prey alone. For Atlantic cod, an historically dominant piscivore in the region, we found that both historical and future warming led to a decline in the proportion of prey speciesâ range it occupied and caused a potential reduction in its ability to exert top-down control on these prey. In contrast, the potential for overlap of spiny dogfish with prey species was enhanced by warming, expanding their importance as predators in this system. In sum, the decline in the ecological role for cod that began with overfishing in this ecosystem will likely be exacerbated by warming, but this loss may be counteracted by the rise in dominance of other piscivores with contrasting thermal preferences. Functional diversity in thermal affinity within the piscivore guild may therefore buffer against the impact of warming on marine ecosystems, suggesting a novel mechanism by which diversity confers resilience
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