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At least 37 records · Page 2Linked to original sources

Effects of mountain lion predation on reducing feral horse population growth rates: Panacea or pipedream?

A goal of applied ecology is to evaluate how demographic rates contribute to population growth and how demography might be manipulated to achieve management objectives. In western North America, many feral horse ( Equus caballus ) populations occupying public lands are protected by federal law and managed for site-specific numerical targets. However, feral horses can exhibit population growth rates exceeding 20% per yr, which can lead to overpopulation, and therefore conflict with other permitted land uses. In response, some stakeholder groups have advocated for natural solutions to the problem of rapid growth and overabundance. Mountain lion ( Puma concolor ) predation has been hypothesized to have suppressive effects on horse population growth rates under some conditions. Here, we evaluated the degree to which this phenomenon might reduce feral horse growth rates using elasticity analysis, scenario analysis with simulations, and an empirical state-space model for a horse population in southeastern Nevada subject to chronic predation. Age-specific elasticities revealed that annual population growth rates (λ) were more sensitive to perturbations in foal and yearling survival rates than for older age-classes. This finding, in conjunction with empirical measures indicating that foals comprised approximately 60% of horses killed by mountain lions, suggests that predation may have greater potential to reduce horse population growth rates than previously recognized. Scenario analysis predicted that horse populations could decrease to target levels within 10 years if predation reduced: (1) annual foal survival by 80% each year, or (2) annual survival rates of foals, yearlings, and 2-year olds by >60%. The state-space model indicated that the heavily predated Nevada horse population experienced positive population growth during 2022 and 2023 (λ = 1.07, both years). Using information on known predation-caused mortalities from 2020–2021, our model predicted that population growth rate in the absence of predation (‘predicted λ’) would have been approximately twice as high (predicted λ 2020 = 1.14; predicted λ 2021 = 1.14 in 2021). Taken together, our results suggest that predation is unlikely to singularly induce stable or negative population growth of feral horses. That said, our findings suggest two aspects of predation that may benefit resource managers. First, chronic predation may reduce λ, thereby increasing the time required for populations to either recover from declines, or exceed management objectives; and second, predation may be most effective in achieving management objectives for horse populations when combined with other interventions, such as removals or fertility control treatments.

Nevada↗

Unveiling a legacy of fish introductions to mountain lakes using historical records and eDNA surveys in a National Park

Across the western United States, introductions of non-native fish into historically fishless mountain lakes have impacted native biota. Understanding the impacts of fish introductions is essential for conservation in Olympic National Park, a Biosphere Reserve. We reconstructed fish plantings using records dating back to 1930, followed by environmental DNA (eDNA) surveys to estimate the current distribution of fish and amphibians in 117 remote mountain lakes. We used Bayesian multiscale occupancy models to determine how lake attributes and planting history related to fish and amphibian occupancy. The most frequently detected species were Brook Trout, Rainbow Trout, Cascades Frog, and Northwestern Salamander. eDNA sampling revealed 52 lakes with amphibians only, 45 with fish and amphibians, 14 with fish only, and 6 unoccupied. Of the 53 lakes with planting records, 38 had fish eDNA detected. Fish eDNA was also detected in 21 lakes lacking planting records, which could reflect incomplete records, unauthorized plantings, and false positive detections. Of the three species planted, Cutthroat Trout had the highest failure rate and did not become established in 23 of 28 historically planted lakes. In a subset of 9 lakes sampled for up to 7 years, those with known fish and amphibian presence showed consistent eDNA detections over time. The number of times a lake was stocked was the best predictor of occupancy for Brook and Rainbow trout, while higher occupancy for Brook Trout was also associated with lower elevations, lower solar radiation, and larger lake area. We did not observe widespread negative associations between amphibian occupancy and fish presence, although there was a negative relationship between fish presence and Rough-skinned Newt and Long-toed Salamander occupancy. Cascades Frog occupancy showed no relationship to fish presence or lake traits. Our results suggest mechanisms of fish persistence over time and highlight areas where native amphibians are impacted by introduced fish. These results can guide management options like targeted fish removals that benefit native fauna while still supporting recreational fishing. More broadly, our work demonstrates the value of combining historical records with contemporary surveys and the utility of eDNA for broad-scale surveys of species distribution in remote wilderness areas.

Washington↗

Captivity may broadly impede bison ecological function: Space, season, and management

American bison ( Bos bison ) were spared from numerical extinction but considered to be ecologically extinct, partially due to spatial restrictions in their former range. A key component of the ecological function of bison is their ability to adjust their spatial behaviors at multiple scales to match the seasonal distributions and availability of resources. To understand how management influences the amount and seasonality of space bison use at various scales, we estimated home range using autocorrelated kernel density estimators (95% utilization distribution) and foraging patch size by the maximum variance in first-passage time at four temporal scales (annual, growing, nongrowing, and focal seasons) for two free-ranging and three captive bison herds. The seasonal differences in space-use within management regimes and study areas were treated as nonparametric related measures while differences amongst management regimes and study areas were treated as nonparametric independent measures. Seasonal variations in space-use were detected in both management regimes, but only free-range bison depicted this pattern at the larger home range scale (p < 0.001). Free-range bison had significantly larger home ranges across seasons compared to captive bison (p < 0.001), but captive bison had larger foraging patch sizes during the growing season than free-range bison. Study areas with captive bison did not differ in their amount of space-use at any scale or season (p > 0.05). The strongest differences were apparent among study herds in annual home range size (p < 0.001) and growing season foraging patch size (p < 0.001). Our results demonstrate that captivity likely prevents bison from using their available landscape seasonally at broad scales, which could have ecological consequences for this historically nomadic herbivore. Although sociopolitical realities prevent bison restoration at a continental scale, increasing the amount of space available to bison where possible has the potential to replicate previous ecological processes. Further research can evaluate the influence of local environmental conditions on seasonality of bison space-use and can assess effects of scale on the ecological impacts of bison.

Colorado, Montana, Texas, Utah↗

Mountain lion prey-selection in a community comprised of native and introduced ungulate species

Species introductions are a hallmark of human influence on ecosystems worldwide. In communities where native and introduced fauna coexist, predators may select prey based on availability or vulnerability. Free-roaming feral horses ( Equus caballus ) are a recent addition to North America and have become widespread, abundant, and in some areas serve as major prey for mountain lions ( Puma concolor ), a native carnivore. The proliferation of horses as well as potential effects of mountain lion predation on native ungulates create ecological and social management challenges; our goal was to assess mountain lion prey selection in a system composed of native mule deer ( Odocoileus hemionus ) and introduced feral horses. Our objectives were to: (1) describe seasonal patterns of prey use within individual mountain lion home ranges; (2) quantify prey use relative to availability; and (3) determine seasonal kill rates on the two primary ungulates in the study area. Fieldwork occurred in southeastern Nevada, 2021–2022. We identified prey use by investigating cache sites from 6 GPS-collared mountain lions. Prey availability and relative abundance were estimated with 49 camera traps distributed across the 3,158-km² study area. During the growing season, weekly kill rates averaged 0.22 deer and 0.55 horses, and in winter, 1.43 deer and 0.33 horses. Thus, lions killed horses at 2.54 times the rate of deer in the growing season but deer at 4.33 times the rate of horses in winter. Model selection indicated mule deer density and prey age class were the strongest predictors of prey species. Lions selected adult deer over fawns, and foals over adult horses, suggesting choices may be driven by optimal prey size rather than species. Mountain lions prey on foals in areas with relatively high mule deer densities, suggesting deer presence may increase foal vulnerability. We hypothesize that lions select foals when available, potentially reducing pressure on mule deer and/or supporting larger lion populations than would occur without this additional prey source. Although individual-level data on mountain lions are challenging to obtain, such information could help managers identify individuals for removal or conservation, improving predator-management outcomes in mixed-prey systems.

Nevada↗

Evaluating contributions of recent tracking-based animal movement ecology to conservation management

The use of animal-born sensors for location-based tracking and bio-logging in terrestrial systems has expanded dramatically in the past 10 years. This rapid expansion has generated new data on how animals interact with and respond to variation in their environment, resulting in important ecological, physiological, and evolutionary insights. Although understanding the finer details of animal locations has important management relevance, applied studies are not prominent in the movement ecology literature. This is despite the long history of applied studies of animal movement and the urgent and growing need for evidence-based conservation guidance, especially in the challenging field of human-wildlife interactions. The goal of this review is to evaluate the realized contribution of tracking-based animal movement ecology to solving specific conservation problems, and to identify barriers that may hinder expansion of that contribution. To do this, we (a) briefly review the history and technologies used in animal tracking and bio-logging, (b) use a series of literature searches to evaluate the frequency with which movement ecology studies are designed to solve specific conservation problems, and (c) use this information to identify challenges that may limit the applied relevance of the field of movement ecology, and to propose pathways to expand that applied relevance. Our literature review quantifies the limited extent to which research in the field of movement ecology is designed to solve specific conservation problems, but also the fact that such studies are slowly becoming more prevalent. We discuss how barriers that limit application of these principles are likely due to constraints imposed by the types of data used commonly in the field. Problems of scale mismatch, error compounding, and data paucity all create challenges that are relevant to the field of movement ecology but may be especially pertinent in applied situations. Finding solutions to these problems will create new opportunity for movement ecologists to contribute to conservation science.

Frontiers in Ecology and Evolution↗

Facing our freshwater crisis via fluid and agile communication: A grand challenge

Earth has been labeled the blue planet because of its abundance of water that covers most of its surface, but the majority is salt water in our oceans. Oceans account for ~352 million km 2 or 69% of the planet's surface, land for 150 million km 2 or 29%, and fresh water for 9 million km 2 or 2% ( Shiklomanov, 2000 ). Most of the fresh water is locked away in glaciers and ice sheets on Greenland and Antarctica, with less than a third accessible to biota ( Shiklomanov, 2000 ). This miniscule fraction of fresh water is our most precious natural resource, the foundation for life in terrestrial environments, and humanity depends on it, but the resource faces enormous threats. My aim in this brief editorial is to define the freshwater resource, succinctly summarize the major threats it faces, and underscore recent calls for conservation. My review is cursory, but I call attention to various recent exhaustive reviews. I end with my views on how journals can help advance global freshwater conservation efforts.

Frontiers in Freshwater Science↗

Linking evolutionary potential to extinction risk: Applications and future directions

Extinction-risk assessments play a major role in prioritizing conservation action at national and international levels. However, quantifying extinction risk is challenging, especially when including the full suite of adaptive responses to environmental change. In particular, evolutionary potential (EP), the capacity to evolve genetically based changes that increase fitness under changing conditions, has proven difficult to evaluate, limiting its inclusion in risk assessments. Theory, experiments, simulations, and field studies all highlight the importance of EP in characterizing and mitigating extinction risk. Disregarding EP can therefore result in ineffective allocation of resources and inadequate recovery planning. Fortunately, proxies for EP can be estimated from environmental, phenotypic, and genetic data. Some proxies can be incorporated into quantitative extinction-risk assessments, whereas others better inform basic conservation actions that maximize resilience to future change. Integration of EP into conservation decision-making is challenging but essential and remains an important area for innovation in applied conservation science.

Frontiers in Ecology and the Environment↗

The benefits of big-team science for conservation: Lessons learned from trinational monarch butterfly collaborations

Many pressing conservation issues are complex problems caused by multiple social and environmental drivers; their resolution is aided by interdisciplinary teams of scientists, decision makers, and stakeholders working together. In these situations, how do we generate science to effectively guide conservation (resource management and policy) decisions? This paper describes elements of successful big-team science in conservation, as well as shortcomings and lessons learned, based on our work with the monarch butterfly ( Danaus plexippus ) in North America. We summarize literature on effective science teams, extracting information about elements of success, effective implementation approaches, and barriers or pitfalls. We then describe recent and ongoing conservation science for the monarch butterfly in North America. We focus primarily on the activities of the Monarch Conservation Science Partnership–an international collaboration of interdisciplinary scientists, policy experts and natural resource managers spanning government, non-governmental and academic institutions—which developed science to inform imperilment status, recovery options, and monitoring strategies. We couch these science efforts in the adaptative management framework of Strategic Habitat Conservation, the business model for conservation employed by the US Fish and Wildlife Service to inform decision-making needs identified by stakeholders from Canada, the United States, and Mexico. We conclude with elements critical to effective big-team conservation science, discuss why science teams focused on applied conservation problems are unique relative to science teams focusing on traditional or theoretical research, and list benefits of big team science in conservation.

Frontiers in Environmental Science↗

Invasive carps versus native fish: A first-pass trait-based index for assessing competition threats.

Introduction: Bigheaded carp ( Hypophthalmichthys spp.) are invasive fish in the Mississippi River basin. Their rapid proliferation has raised concerns about exploitative competition with native fishes, with consequences that remain incompletely understood. We aimed to identify native species most susceptible to competition based on overlap with bigheaded carp in dietary and habitat traits. Methods: We used an established fish traits database to quantify dietary and habitat overlap between bigheaded carp and 100 native fish species. We then integrated dietary and habitat overlap into a composite competition index. Results: Dietary similarity with the native assemblage exceeded habitat similarity, suggesting that while competition with some native species may occur, it may often be limited by spatial separation. Dietary and habitat similarity coefficients were not correlated, indicating that strong dietary overlap did not necessarily coincide with similar habitat use (and vice versa). Approximately 20% of species were classified as high competition risk. The highest-risk species included bigmouth buffalo ( Ictiobus cyprinellus ), threadfin shad ( Dorosoma petenense ), black redhorse ( Moxostoma duquesnii ), bluntnose minnow ( Pimephales notatus ), highfin carpsucker ( Carpiodes velifer ), and gizzard shad ( Dorosoma cepedianum ). Discussion: Although trait-based predictions have limitations, our results are consistent with empirically documented interactions and provide a rapid, first-pass assessment of potential competitive vulnerability. Dietary overlap, habitat overlap, and the derived competition index offer actionable decision-support for managing potential competition between bigheaded carp and native species. We included ten practical recommendations to translate predictions into conservation and management actions.

Alabama, Kentucky, Mississippi, North Carolina, So↗

Coral reef restorations can be optimized to reduce coastal flooding hazards

Coral reefs are effective natural coastal flood barriers that protect adjacent communities. Coral degradation compromises the coastal protection value of reefs while also reducing their other ecosystem services, making them a target for restoration. Here we provide a physics-based evaluation of how coral restoration can reduce coastal flooding for various types of reefs. Wave-driven flooding reduction is greatest for broader, shallower restorations on the upper fore reef and between the middle of the reef flat and the shoreline than for deeper locations on the fore reef or at the reef crest. These results indicate that to increase the coastal hazard risk reduction potential of reef restoration, more physically robust species of coral need to be outplanted to shallower, more energetic locations than more fragile, faster-growing species primarily being grown in coral nurseries. The optimization and quantification of coral reef restoration efforts to reduce coastal flooding may open hazard risk reduction funding for conservation purposes.

Frontiers in Marine Science↗

Principles of translational science education

In a recent special issue in Frontiers in Ecology and the Environment, Enquist et al. (2017) present a welcome streamlining of modern applied ecology emphasizing a collaborative approach to applied ecological research involving resource-managers and scientists to produce actionable science: translational ecology (TE). The authors, including ecologists, social scientists, and conservation professionals, identified six principles defining the practice of translational ecology: collaboration, engagement, commitment, communication, process, and framing (Figure 1). In thinking about how science education can be enhanced by directly involving researchers in science education, we recognized remarkable overlap between the principles of translational ecology (Enquist et al. 2017) and a framework for developing mutually beneficial integrative partnerships between scientists and educators. Here, we describe scientist-educator analogies of the six principles of translational ecology: translational science education (TSE).

Frontiers in Ecology and Evolution↗

Modeling fine-scale coral larval dispersal and interisland connectivity to help designate mutually-supporting coral reef marine protected areas: Insights from Maui Nui, Hawaii

Connectivity among individual marine protected areas (MPAs) is one of the most important considerations in the design of integrated MPA networks. To provide such information for managers in Hawaii, USA, a numerical circulation model was developed to determine the role of ocean currents in transporting coral larvae from natal reefs throughout the high volcanic islands of the Maui Nui island complex in the southeastern Hawaiian Archipelago. Spatially- and temporally-varying wind, wave, and circulation model outputs were used to drive a km-scale, 3-dimensional, physics-based circulation model for Maui Nui. The model was calibrated and validated using satellite-tracked ocean surface current drifters deployed during coral-spawning conditions, then used to simulate the movement of the larvae of the dominant reef-building coral, Porites compressa , from 17 reefs during eight spawning events in 2010–2013. These simulations make it possible to investigate not only the general dispersal patterns from individual coral reefs, but also how anomalous conditions during individual spawning events can result in large deviations from those general patterns. These data also help identify those reefs that are dominated by self-seeding and those where self-seeding is limited to determine their relative susceptibility to stressors and potential roadblocks to recovery. Overall, the numerical model results indicate that many of the coral reefs in Maui Nui seed reefs on adjacent islands, demonstrating the interconnected nature of the coral reefs in Maui Nui and providing a key component of the scientific underpinning essential for the design of a mutually supportive network of MPAs to enhance conservation of coral reefs.

Hawaii↗

Novel insights into the genetic population connectivity of transient whale sharks (Rhincodon typus) in Pacific Panama provide crucial data for conservation efforts

The whale shark ( Rhincodon typus ) is an endangered and highly migratory species, of which solitary individuals or aggregations are observed in oceans worldwide and for which conservation efforts are hindered by a lack of comprehensive data on genetic population connectivity. Tissue samples were collected from wandering whale sharks in Pacific Panama to determine genetic diversity, phylogeographic origin, and possible global and local connectivity patterns using a 700–800 bp fragment of the mitochondrial control region gene. Genetic diversity among samples was high, with five new haplotypes and nine polymorphic sites identified among the 15 sequences. Haplotype diversity ( H d = 0.83) and nucleotide diversity (π = 0.00516) were similar to those reported in other studies. Our sequences, in particular haplotypes PTY1 and PTY2 , were similar to those previously reported in the Arabian Gulf and the Western Indian Ocean populations (a novel occurrence in the latter case). Haplotypes PTY3 , PTY4 , and PTY5 were similar to populations in Mexico and the Gulf of California. In contrast, the only populations to which our Panamanian sequences were genetically dissimilar were those from the Atlantic Ocean. The absence of reference sequences in GenBank from southern sites in the Eastern Tropical Pacific, such as Galapagos (Ecuador), Gorgona and Malpelo Islands (Colombia), and Coco Island (Costa Rica), reduced our capacity to genetically define regional patterns. Genetic differentiation and connectivity were also assessed using an analysis of molecular variance (AMOVA), which showed a similar population structure (five groups) to the neighbor-joining tree. Other population features based on neutrality tests, such as Tajima’s D and Fu’s Fs statistics, showed positive values for Panama of 0.79 and 1.61, respectively. Positive values of these statistics indicate a lack of evidence for population expansion among the sampled individuals. Our results agree with previous reports suggesting that whale sharks can travel over long distances and that transboundary conservation measures may be effective for species protection.

Gulf of Chiriqu↗

Marine threats overlap key foraging habitat for two imperiled sea turtle species in the Gulf of Mexico

Effective management of human activities affecting listed species requires understanding both threats and animal habitat-use patterns. However, the extent of spatial overlap between high-use foraging areas (where multiple marine species congregate) and anthropogenic threats is not well known. Our modeling approach incorporates data on sea turtle spatial ecology and a suite of threats in the Gulf of Mexico to identify and map “hot spots” of threats to two imperiled turtle species. Of all 820 “high” threats grid cells, our tracked turtles foraged at least one day in 77% of them. Although threat data were not available outside the U.S. Exclusive Economic Zone, our map of turtle and threat “hotspots” can be incorporated in future more comprehensive threat analyses for the region. Knowledge of these shared foraging- and threat-areas can assist managers charged with designing effective conservation and population recovery strategies, in future habitat modeling efforts, and in designations of Gulf of Mexico habitat with high conservation value.

Frontiers in Marine Science↗

Mapping global coral vulnerability to stony coral tissue loss disease: Implications for biosecurity and conservation

Stony Coral Tissue Loss Disease (SCTLD) has devastated Caribbean coral reefs since 2014, but its potential for global impact remains uncertain. We developed predictive models to assess the worldwide vulnerability of coral reefs to SCTLD under different origin and spread hypotheses. Using random forest regression models incorporating coral taxonomy and zooxanthellae clade associations from 52 taxa, we projected SCTLD susceptibility and mortality patterns globally using six indices: Mean susceptibility per genus per location, Summed susceptibilities across genera per location, Summed susceptibilities across genera per realm, Mean mortality per genus per location, Summed mortalities across genera per location, and Summed mortalities across genera per realm. Models demonstrated strong predictive performance (R² = 0.57 for susceptibility; R² = 0.73 for mortality) and revealed that about 7% of coral genera per location are potentially susceptible to SCTLD. While mean susceptibility and mortality per genus were highest in the Tropical Atlantic, the summed susceptibility and mortality across genera were much higher in the biodiverse Central Indo-Pacific. Natural barriers could limit SCTLD’s spread, including the mid-Atlantic gap and the low diversity of the Tropical Eastern Pacific, supporting the contained disease hypothesis. However, the widespread distribution of susceptible genera across coral reef realms indicates significant vulnerability should SCTLD circumvent these barriers through human-mediated transport, particularly via ballast water or the aquarium trade. If SCTLD is an invasive pathogen originating in the Pacific, as shipping patterns for the aquarium trade suggest, mortality in its native range would likely be lower than our projections. These findings point to targeted intervention strategies, including enhanced monitoring at key locations, assessment of biosecurity needs in high-risk areas, and prioritized conservation efforts in vulnerable high-diversity regions to prevent SCTLD from spreading globally.

Frontiers in Marine Science↗

Long-term patterns in growth of White Sturgeon in the Sacramento-San Joaquin River basin, California.

Introduction: The Sacramento-San Joaquin River system (SSJ) of California includes both riverine, delta, and estuarine habitats and is among the most modified aquatic ecosystems in the United States. Water development projects in the system are associated with declines of many native species, including White Sturgeon Acipenser transmontanus . Methods: We used White Sturgeon pectoral fin rays collected from 1983 to 2016 throughout the SSJ to assess long-term changes in growth and associations with thermal and hydrological conditions (i.e., temperature, discharge, salinity). Age and growth were estimated from 1,897 White Sturgeon varying in fork length from 25 to 210 cm and from age 0 to 33. Results: Age structure varied through time with the oldest fish generally sampled during the mid-1980s. Growth of White Sturgeon in 1951–1970 was slower than growth of fish in 1971–1990 and 1991–2012. Growth of White Sturgeon during 1991–2012 was ~10% higher than during other time periods. Discussion: Little variation in growth was explained by environmental covariates, suggesting that annual growth was likely influenced by factors not measured in our study. Alternatively, population structure and movement behavior of White Sturgeon in the SSJ may be such that the scale (i.e., spatial or temporal) of available habitat covariates was mismatched to the scale at which growth of White Sturgeon responds. Increased growth in recent times may be partly due to density-dependent processes in association with substantial declines in White Sturgeon population abundance over the last several decades. This research provides important information on long-term patterns in growth that contributes to the conservation and management of White Sturgeon in the SSJ and beyond.

California↗