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Native Cutthroat Trout Oncorhynchus clarkii spp. populations in the western U.S. have declined in part due to displacement by nonnative trout, but mechanisms to explain displacement vary by species and geography. Using a production framework, we demonstrated allopatric populations of Rio Grande Cutthroat Trout O. c. virginalis (RGCT) exhibited consistently higher biomass and secondary production rates (0.19–0.92 g DM·m-2·yr-1) than sympatric populations with Brown Trout Salmo trutta (0.01–0.05 g DM·m-2·yr-1) and that an interactive temperature effect on RGCT biomass and production was overshadowed by the presence of Brown Trout across cold and warm streams. Interestingly, over half of trout production was fueled...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
We studied the impacts of drought and invasive trout on survival and productivity on Rio Grande cutthroat trout (Oncorhynchus clarkii virginalis, RGCT) populations. Rio Grande cutthroat trout is the southernmost subspecies of cutthroat trout and endemic to the Rio Grande, Canadian, and Pecos River basins of Colorado and New Mexico. The subspecies is reduced to less than 11% of its historic range with most populations occupying isolated high elevation headwater streams. One of the greatest threats to its survival is the effect that low stream flow due to drought will have on this coldwater trout living at the edge of its range. Our work will provide insight into the current and future threats of RGCT populations...
Categories: Publication; Types: Citation
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
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Species that inhabit the arid Southwest are adapted to living in hot, dry environments. Yet the increasing frequency and severity of drought in the region may create conditions that even these hardy species can’t survive. This project examined the impacts of drought in the southwestern U.S. on four of the region’s iconic species: desert bighorn sheep, American pronghorn, scaled quail, and Rio Grande cutthroat trout. Grasping the impacts of drought on fish and wildlife is critical for management planning in the Southwest, as climate models project warmer, drier conditions for the region in the future. Species are known to respond to environmental changes such as drought in different ways. Often, before changes...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
The responses of individual species to environmental changes can be manifested at multiple levels that range from individual-level (i.e., behavioral responses) to population-level (i.e., demographic) impacts. Major environmental changes that ultimately result in population level impacts are often first detected as individual-level responses. For example, herbivores respond to limited forage availability during drought periods by increasing the duration of foraging periods and expanding home range areas to compensate for the reduction in forage. However, if the individual-level responses are not sufficient to compensate for reduced forage availability, reduced survival and reproductive rates may result. We studied...
Abstract (from Transactions of the American Fisheries Society): Density-dependent (DD) and density-independent (DI) effects play an important role in shaping fish growth rates, an attribute that correlates with many life history traits in fishes. Consequently, understanding the extent to which DD and DI effects influence growth rates is valuable for fisheries assessments because it can inform managers about how populations may respond as environmental conditions continue to change (e.g., threats from climate change). We used a Rio Grande Cutthroat Trout Oncorhynchus clarkii virginalis (RGCT) capture–mark–recapture data set collected over 2 years along a temperature and density gradient in northern New Mexico streams...
Categories: Publication; Types: Citation
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This data set characterizes the thermal regime in a number of Colorado and New Mexico streams that contain populations of Rio Grande Cutthroat Trout (Oncorhynchus clarkii virginalis) or have been considered potential restoration areas for the fish. The majority of these streams had no previous record of continual temperature records. When compared to Colorado water temperature criteria (Cold Tier 1), a portion of these populations appeared to be at risk from elevated stream temperatures, as indicated by exceedance of both acute and chronic water quality metrics. Summer water temperature profiles recorded at sites within current Rio Grande Cutthroat Trout habitat indicated that although the majority of currently...
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Drought poses a major threat to New Mexico’s state fish, the Rio Grande cutthroat trout. This southernmost subspecies of cutthroat trout, found only in New Mexico and Colorado, has already been restricted to an estimated 12% of its former range. Now climate change, in the form of lower winter snowpack and reduced precipitation, challenges its long-term persistence. This trout tends to occupy small and fragmented streams, which are at higher risk of drying up during drought events. Yet, the full extent of drought impacts to Rio Grande cutthroat trout is unknown. To address this knowledge gap, researchers examined the effects of drought - in particular stream intermittency - on the growth and survival of Rio Grande...
    map background search result map search result map The Impacts of Drought on Fish and Wildlife in the Southwestern U.S. The Effects of Drought on Rio Grande Cutthroat Trout: The Role of Stream Intermittency Water and Air Temperature Throughout the Range of Rio Grande Cutthroat Trout in Colorado and New Mexico; 2010-2015 V2 Effects of Non-native Brown Trout and Temperature on the Production of Rio Grande Cutthroat Trout Populations The Effects of Drought on Rio Grande Cutthroat Trout: The Role of Stream Intermittency Effects of Non-native Brown Trout and Temperature on the Production of Rio Grande Cutthroat Trout Populations Water and Air Temperature Throughout the Range of Rio Grande Cutthroat Trout in Colorado and New Mexico; 2010-2015 V2 The Impacts of Drought on Fish and Wildlife in the Southwestern U.S.