Ecological Applications[JOURNAL]
Sun
200 papers
Molecular assessment of food web dynamics identifies critical periods for managing resilience in biological pest control.
Branco Leote PN, Rennstam Rubbmark OR, Traugott M
Ecol Appl · 2025 Jul · PMID 40744864 · Full text
Food webs are not static over time, but our knowledge of their dynamics is extremely scarce due to methodological challenges. In turn, this significantly limits our ability to mechanistically understand the temporal chan...
Food webs are not static over time, but our knowledge of their dynamics is extremely scarce due to methodological challenges. In turn, this significantly limits our ability to mechanistically understand the temporal changes that trophic networks annually undergo. Here, we address this gap using DNA-based diet analysis to measure the season-wide dynamics of trophic interactions between invertebrate generalist predators, pest, and alternative prey in replicated cereal fields across 2 years. We used the level of food web specialization as a proxy for predator diet overlap in pest control and hypothesized that it would reach its minimum at the middle point of the season, when primary production should be higher (H1). Conversely, invertebrate diversity would reach its maximum during the same period (H2). Additionally, alternative prey availability would be indirectly increased by adding manure to half of each field to test if this would reduce specialization and increase diversity (H3). In line with our predictions, food web specialization was lowest during the middle of the season, when prey, but not predator, diversity reached its maximum. No significant effects of manure addition were found on food web specialization. Our findings suggest early and late season in cereal systems as the times when generalist predators are behaviorally most constrained, pinpointing these as periods when the pests are eaten by a smaller subset of the predator community. Hence, molecular trophic analyses provide unique insights into the temporal dynamics of food webs and their properties. This allows the generation of temporal roadmaps for when management interventions are expected to be most effective.
Removing dead coral after marine heatwaves can mitigate coral-algae competition and increase viable coral recruitment.
Kopecky KL, Pavoni G, Corsini M … +4 more , Brooks AJ, DiFiore BP, Menna F, Nocerino E
Ecol Appl · 2025 Jul · PMID 40721269 · Full text
Ecological disturbance regimes are shifting and leaving behind novel legacies, like the remnant structures of dead foundation species, which have poorly known impacts on ecosystem resilience. We explored how dead coral s...
Ecological disturbance regimes are shifting and leaving behind novel legacies, like the remnant structures of dead foundation species, which have poorly known impacts on ecosystem resilience. We explored how dead coral skeletons produced by marine heatwaves-material legacies of increasingly common disturbances on coral reefs-influence spatial competition between corals and macroalgae, focusing on whether removing dead branching skeletons stimulates recovery of coral after disturbance. Following a marine heatwave, we removed dead skeletons from reef patches and then used underwater photogrammetry and AI-powered image analysis to quantify trajectories of coral and macroalgae. After four years, removal of dead skeletons resulted in 1.6 times more live coral remaining and reduced development of macroalgae by half, relative to patches where skeletons were left intact. Dead skeletons acted as an alternate substrate type that facilitated macroalgae development, and greater macroalgal abundance caused steeper declines in live coral. Lastly, removal of dead skeletons led to five times greater densities of coral recruits on stable (primary) reef substrate than on comparatively unstable branching coral skeletons. Our findings identify a promising avenue to manage for coral resilience (on reefs where carbonate budgets are not in a deficit) and reveal how material legacies of changing disturbance regimes can alter physical environments to sway the outcomes of spatial competition.
Long-term effects of haying and prescribed fire on the composition and diversity of wet prairie plant communities.
Beck JJ, Kiefer G, Johnson R … +3 more , Winter B, Dana R, Wagenius S
Ecol Appl · 2025 Jul · PMID 40717287 · Full text
Plant species composition and diversity in many terrestrial ecosystems depend on frequent disturbances. Management of these historically disturbance-dependent habitats often requires replicating past disturbance regimes...
Plant species composition and diversity in many terrestrial ecosystems depend on frequent disturbances. Management of these historically disturbance-dependent habitats often requires replicating past disturbance regimes or implementing management approaches that mimic their ecological effects. For example, efforts to manage North American tallgrass prairie frequently utilize prescribed fire to maintain these historically fire-dependent grasslands. However, alternatives to prescribed fire, such as haying, have attracted the interest of conservation practitioners and landowners. The paucity of long-term experiments, especially in wet prairies and sedge meadows, limits our understanding of how these different management techniques influence the composition and diversity of such perennial-dominated plant communities. We conducted a 23-year experiment within a remnant wet prairie complex in northwestern Minnesota, USA, to evaluate the effects of haying and prescribed burning on plant species richness and community composition. Experimental treatments-no active management (control), annual late-summer haying, spring burns at 4-year intervals, and fall burns at 4-year intervals-were applied continuously between 1999 and 2021. Spring burning at 4-year intervals tended to maintain the highest species richness while fall burning at 4-year intervals supported intermediate levels of species richness similar to control plots. For the first 10 years of the experiment, species richness in the annually hayed plots was comparable to the burned and control plots. Thereafter, richness declined rapidly in the hayed plots, leading to a 30% drop in species richness between 2010 and 2021. Annual haying also altered plant composition at a rate that far outpaced compositional changes in other treatments. Temporal shifts in plant community composition reflected idiosyncratic species' responses to experimental treatments. Many of these species-specific responses to treatments were delayed, becoming apparent more than a decade after treatments were initiated. Annual haying and prescribed fire have distinctive long-term ecological effects on wet prairie plant communities and should not be considered interchangeable management options. Continuous annual haying erodes plant diversity in wet prairies and shifts plant composition while periodic spring fires tend to maximize local plant richness. This study exemplifies the importance of conducting long-term experiments to better inform management of disturbance-dependent habitats.
Simulations of historical impacts of climate change and atmospheric chemistry on a northeastern U.S. forest ecosystem.
Meng L, Pourmokhtarian A, Templer PH … +2 more , Hutyra LR, Driscoll CT
Ecol Appl · 2025 Jul · PMID 40702586 · Publisher ↗
Climate change, land disturbance, and atmospheric chemistry have substantially impacted northeastern hardwood forests. However, it is challenging to quantify the exacerbating or mitigating interactions among these distur...
Climate change, land disturbance, and atmospheric chemistry have substantially impacted northeastern hardwood forests. However, it is challenging to quantify the exacerbating or mitigating interactions among these disturbances on carbon (C), nitrogen (N), and water cycling in forest ecosystems. To evaluate these effects, we applied the PnET-CN-daily model to simulate the historical patterns of C, N, and water cycling at Harvard Forest in central Massachusetts, United States. The model was run with a reconstructed historical climate and air chemistry scenario, and results were compared with field measurements at Harvard Forest for calibration. The calibrated model was then run with a series of hypothetical scenarios to decompose the impacts of individual environmental drivers on C, N, and water cycling of the forest ecosystem. Model simulations suggest that increases in atmospheric carbon dioxide (CO) concentrations, changes in climate, and decreases in atmospheric N deposition have contributed to historical changes in the plant C cycle. Elevated CO concentrations have been the dominant factor, though these effects have diminished with increasing concentrations. The combination of elevated CO and a warmer climate has led to increased plant growth, resulting in higher plant N storage but a decline in the soil N pool. However, elevated atmospheric N deposition has mitigated this decline in soil N and also suppressed soil decomposition. Climate has been a key driver of recent changes in the water cycle, with increased air temperatures leading to higher transpiration rates. Despite this change, soil water content at Harvard Forest remained relatively constant over the simulation period because of increasing water-use efficiency associated with increasing CO concentration, indicating that plant growth is not limited by water at Harvard Forest. Future investigations should use modeling approaches to project the functional responses of the forest ecosystem to the interacting effects of future climate scenarios and contrasting air quality regulations.
Indigenous knowledge, forest landscape modeling, and the cumulative effects of environmental changes.
Bélisle AC, Mantyka-Pringle C, Boulanger Y … +5 more , Croteau B, Wapachee A, Drapeau LJ, Desrochers M, Asselin H
Ecol Appl · 2025 Jul · PMID 40691771 · Full text
Boreal landscapes are exposed to climate change, forestry, and other industrial stressors with consequences for Indigenous people's wellbeing and relationship with traditional lands. As a collaborative and transdisciplin...
Boreal landscapes are exposed to climate change, forestry, and other industrial stressors with consequences for Indigenous people's wellbeing and relationship with traditional lands. As a collaborative and transdisciplinary research team including researchers and students from universities, Indigenous communities, and government and non-government organizations, we addressed the consequences of these environmental changes for an Eeyou (Cree) community and an Anishnaabe community in Eastern boreal Canada (Quebec). Our aims were to (1) develop a landscape value model combining qualitative and quantitative data as well as knowledge from Indigenous land-use experts and forest landscape simulations; (2) evaluate the vulnerability of Indigenous landscape values to environmental changes; and (3) assess the relative importance of climate change and forestry as drivers of environmental changes. We developed a set of 12 variables based on interviews with Indigenous experts, describing four dimensions of landscape value: abundance, quality, access, and experience. We then performed forest landscape simulations (2000-2100) with the model LANDIS-II using scenarios combining climate change and forestry gradients. We presented the simulation outputs to Indigenous experts and elicited the probability of fulfilling their needs in the future. We combined Indigenous knowledge and forest landscape simulations within a probabilistic model (Bayesian network). The projections indicate that rapid and acute changes in forest structure and composition are to be expected. The most vulnerable values are those associated with mature and undisturbed forests and include the ability to trap, hunt moose, and recover health and energy from the land (ressourcement in French, KOKi OTAPiNAN NOPiMiK iNATiSi8iN in Anishnaabemowin). Timber harvesting rate influences the timing and amplitude of change. The influence of climate change varied from one region to another and was mostly associated with wildfire frequency. Adaptation strategies may include reducing timber harvesting rates, implementing wildfire-prevention measures, and valuing alternative forest uses.
Restoration maintains high soil carbon stocks in Asia's largest tropical grassland.
Bhan M, Misher C, Hiremath A … +1 more , Vanak AT
Ecol Appl · 2025 Jul · PMID 40679165 · Publisher ↗
Land management changes threaten the ecological functionality of grassland ecosystems worldwide, including the ability of these ecosystems to store carbon in their soils. The Banni grasslands in India, Asia's largest tro...
Land management changes threaten the ecological functionality of grassland ecosystems worldwide, including the ability of these ecosystems to store carbon in their soils. The Banni grasslands in India, Asia's largest tropical grassland, are no different in this regard. Despite being a highly biodiverse ecosystem with an extensive land use history, information on soil carbon stocks in this ecosystem remains conspicuously absent. In this study, we map soil organic carbon (SOC) stocks within the upper 30 cm depth across land use-land cover classes by combining high-resolution satellite imagery with field-based soil carbon data from a network of long-term monitoring sites. We find that Banni currently stores 27.69 million tons of carbon in its soils, with an average SOC density of 119.61 ± 3.50 tons of carbon per hectare (tC/ha, mean ± SE). These estimates compare favorably with arid and semi-arid grasslands as well as seasonally flooded savannas across the tropics. The highest SOC densities are found in restored grasslands (142.72 ± 5.72 tC/ha), reaffirming the potential of carbon recovery from ecological restoration. Tracing 10 years of land change in the region indicates the further expansion of the invasive tree Prosopis juliflora across the landscape, but its impacts on changes in SOC concentration estimates remain varied. Our results indicate the large SOC storage associated with woody encroachment in Banni and point toward the need for the active management of Banni so that carbon benefits can accrue at meaningful timescales for reversing land degradation and contributing to land-based climate action.
Thinning restores ungulate foraging habitat in historically logged forests.
Manlick PJ, Howe M, Wen J … +2 more , Barnard JC, Nelson KN
Ecol Appl · 2025 Jul · PMID 40657763 · Publisher ↗
Legacies of land use can persist for decades, thereby impacting populations, communities, and ecosystems long after the original disturbance has concluded. The coastal rainforests of western North America were fundamenta...
Legacies of land use can persist for decades, thereby impacting populations, communities, and ecosystems long after the original disturbance has concluded. The coastal rainforests of western North America were fundamentally transformed by commercial logging throughout the 20th century, resulting in depauperate second-growth forests that provide limited understory production and foraging habitat for herbivores. The Tongass National Forest in Alaska, USA, is the largest contiguous tract of coastal temperate rainforest in the world, but nearly 200,000 ha of second-growth forest have created a need to restore understory plant communities and foraging habitat for ungulates like Sitka black-tailed deer (Odocoileus hemionus sitkensis), a regional indicator of forest health and key subsistence resource for local and Indigenous communities. We leveraged a 16-year adaptive management experiment-the Tongass-Wide Young Growth Studies (TWYGS) program-to test the effects of precommercial thinning on forage availability and use by deer in second-growth forests. We measured plant communities, presence-absence of browse, and slash debris in 14,908 quadrats across 730 plots and found that plant community composition, understory forage biomass, digestible energy, and digestible protein were all significantly higher in thinned plots versus controls. Precommercial thinning also doubled browse probabilities relative to unthinned stands, and plots treated within 35 years of stand initiation experienced the highest gains. Deer selected for both plant quantity and plant quality, as browse was positively associated with both digestible energy and digestible protein. Conversely, slash debris generated by precommercial thinning reduced browse probability by an average of 11.3%, but these effects attenuated as slash decomposed over the course of the study. We found no effects of landscape composition on relative browse probability, indicating that fine-scale resource quality and accessibility were the strongest drivers of habitat use by deer over nearly two decades of sampling. Collectively, our results show that precommercial thinning is a valuable management tool that increases forage and deer habitat use in second-growth coastal rainforests. This study highlights the enduring legacies of forest disturbance and underscores the value of adaptive management experiments with long-term monitoring to optimize habitat management for wildlife.
Forecasting alien species establishment and source regions: Quantitative assessment of potential ant invasions in Japan.
Zurápiti Y, Kass JM, Guénard B … +1 more , Economo EP
Ecol Appl · 2025 Jul · PMID 40654182 · Full text
Due to the costs and difficulties of mitigating past biological invasions, there is a critical need for improved predictions of establishment risk for alien species and their source regions to guide the deployment of pre...
Due to the costs and difficulties of mitigating past biological invasions, there is a critical need for improved predictions of establishment risk for alien species and their source regions to guide the deployment of preventive measures. Here, focusing on a global pool of ant species known to be spread by humans, we develop a computational workflow to predict threats for a country or region of interest. Specifically, the workflow (1) predicts which alien species are most likely to be established based on climatic suitability with species distribution models, (2) clusters areas threatened by similar assemblages of alien species, and (3) identifies global regions that can act as important sources for these species. We apply this workflow to estimate which ants with human-assisted invasion histories around the globe may establish in Japan, an island country with broad climatic and topographic diversity. To reduce forecast uncertainty, we exclude models that we assess to result in dubious transfers based on evaluations of species already established in Japan and avoid making model extrapolations. To better account for the full invasion process, we also estimate introduction risk and spread within Japan and integrate these with our establishment risk and potential sources estimates. Our results indicate that all prefectures of Japan have potential risks of new alien ant establishments, though lower latitudes and small archipelagoes have the highest predicted vulnerability. When combined with the likelihood of spread, we expect shifts in vulnerability toward highly populated areas and in proximity to international ports. Interestingly, the source regions with the most alien species presenting establishment threats are in southern Europe and the subtropical Americas rather than in Asia, in part because many Asian species have already been introduced to Japan. When considering introduction risk based on global trade patterns, the United States was most likely to be a source of future introductions. We discuss the implications of these results for global management policies and cargo surveillance. The workflow described here can be deployed worldwide for different taxa to predict the establishment potential of alien invasions and their sources, and also to design more practical and efficient preventive strategies.
High sensitivity to ocean acidification in wild out-migrating juvenile Pacific salmon is not impacted by feeding success.
Frommel AY, Akbarzadeh A, Chalifoux V … +7 more , Ming TJ, Collicutt B, Rolheiser K, Opie R, Miller KM, Brauner CJ, Hunt BPV
Ecol Appl · 2025 Jul · PMID 40643140 · Full text
Salmon populations are declining worldwide, with high mortality rates during juvenile marine migration presenting a bottleneck to recruitment. The ocean conditions along the main migratory route of juvenile salmon in Bri...
Salmon populations are declining worldwide, with high mortality rates during juvenile marine migration presenting a bottleneck to recruitment. The ocean conditions along the main migratory route of juvenile salmon in British Columbia are characterized by high variability in CO, with the amplitude, duration, and frequency of ocean acidification events exacerbated by climate change. Similarly, the variability in ocean conditions affects the abundance and diversity of plankton prey, leading to areas of food paucity for juvenile salmon. We investigated the combined effects of ocean acidification (control and 3200 μatm CO) and food limitation (ad libitum, ½ ration, and food deprived) on the survival, condition, and gene expression profiles of juvenile Chum salmon (Oncorhynchus keta) to develop predictive biomarkers for CO exposure and food deprivation. Ocean acidification caused a direct 3-fold increase in mortality over 25 days of exposure, which was unaffected by food availability but differentially affected smaller fish. CO exposure induced transcriptomic changes in a suite of genes associated with ion regulation, while food deprivation was associated with a differential expression of stress, immune, and mortality markers, as well as reduced condition factor. Our data indicate that CO directly impairs ionoregulatory capacity to the point of failure in juvenile Chum salmon and that these effects cannot be compensated through increased energy from food. Applying our gene panels as biomarkers to a subset of fish with known exposure, we were able to accurately predict exposure to CO and food deprivation (74% and 90%, respectively). By combining these gene panels with previously established biomarkers for other environmental stressors, the recent environmental stress history of wild fish can be determined and can be used in models to predict salmon returns, informing fisheries management and conservation efforts.
Objective risk assessment of bark and ambrosia beetles non-indigenous to North America.
Johnson AJ, Bednar D, Hulcr J
Ecol Appl · 2025 Jul · PMID 40634263 · Full text
Pest risk assessment informs regulatory decisions to facilitate safe trade while also protecting a country's agricultural and environmental resources. The first step in pest risk assessment is pest categorization which c...
Pest risk assessment informs regulatory decisions to facilitate safe trade while also protecting a country's agricultural and environmental resources. The first step in pest risk assessment is pest categorization which can help determine whether an in-depth examination is needed. We created a model to predict the potential impact of non-indigenous bark and ambrosia beetles (Curculionidae: Scolytinae). This model uses biological variables derived from extensive assessment of alien species and produces a five-point scale of impact prediction. We accommodate uncertainty and missing data using random decision tree forests with Monte Carlo simulations. Non-indigenous bark beetles include both invasive species with significant ecological impacts, such as widespread tree death, and others that pose little risk. We assembled a comprehensive list of 60 introduced non-native bark beetle species in the continental United States as the training set. Forty-two potentially predictive variables were chosen from reports on behaviors, pestilence, recorded damage/interpretations in literature, biological traits, and interactions with fungi including plant pathogens. The model builds upon strategies used by USDA-APHIS in existing risk assessments, specifically the Objective Prioritization of Exotic Pests (OPEP) model, with changes in the following: (1) a transparent dataset for building and training the model enabling future updates and use in other systems, (2) uncertainty simulations using values derived from an extensive natural history matrix rather than an assumed equal distribution, and (3) predictions made on the probability of multiple impact levels, allowing users to decide based on acceptable risk. The model is designed for pest risk analysis for Scolytinae in the continental United States but can be adapted to other pests or regions. We tested the model's performance by iteratively removing each species from the training set and retraining the model. The retrained models accurately predicted the removed species. To demonstrate the model's application, we predicted the impact of scolytine beetles not yet present in the continental United States, Xylosandrus morigerus and Hypoborus ficus, plus an additional hypothetical species with no known data. Our model predicts that these species are likely to have moderate impacts and unlikely to have high impacts if they were introduced.
Threshold responses of birds to agricultural intensification in Mediterranean olive groves.
García-Navas V, Tarifa R, Salido T … +4 more , González-Robles A, López-Orta A, Valera F, Rey PJ
Ecol Appl · 2025 Jul · PMID 40634261 · Full text
Olive groves are the most representative crop of the Mediterranean basin. This agroforestry system is undergoing a strong transformation in recent decades as a result of the agricultural intensification process prevailin...
Olive groves are the most representative crop of the Mediterranean basin. This agroforestry system is undergoing a strong transformation in recent decades as a result of the agricultural intensification process prevailing in the Northern Hemisphere. Although some authors have suggested that farmland biodiversity responds non-linearly to the complexity of agricultural landscapes, few studies have used community thresholds to identify potential tipping points. Here, we examined the existence of synchronous responses in bird abundance across a gradient of decreasing agricultural intensification in Spanish olive groves. Our study system comprised 25 sites, each consisting of a pair of farms: one with intensive management and the other one with extensive management of the herbaceous cover. We explored whether bird abundances exhibit non-linear threshold responses to ant abundance and tree density at a local (field) scale, plant diversity (both herbaceous and woody plants) at a local (farm) scale, and to proportion of natural habitat at a landscape scale using Threshold Indicator Taxa ANalysis (TITAN). We found a higher incidence of positive responses with decreasing levels of intensification, and these were not restricted to certain guilds or avian families. Few indicator species showed a significant negative response. Thresholds detected were not sharp but rather gradual changes along the environmental gradients. Although they do not necessarily support evidence of ecological thresholds characterized by rapid changes in species abundance or distribution, these patterns can help identify optimal change points for management decisions. Specifically, our results indicate that reaching a minimum threshold of ~85 and 15 species of herbaceous and woody plants, respectively, per unit of surface can entail a gain in terms of bird diversity for olive farms with virtually no detrimental effects. Overall, this study shows that the adoption of agri-environmental measures like the maintenance of ground cover and patches of natural habitat has a positive impact on different species inhabiting this woody crop, and this effect occurs at different spatial scales.
Aspen impedes wildfire spread in southwestern United States landscapes.
Harris MP, Coop JD, Balik JA … +3 more , McFarland JR, Parks SA, Stevens-Rumann CS
Ecol Appl · 2025 Jul · PMID 40621807 · Full text
Aspen (Populus tremuloides) forests are generally thought to impede fire spread, yet the extent of this effect is not well quantified in relation to other vegetation types. We examined the influence of aspen cover on int...
Aspen (Populus tremuloides) forests are generally thought to impede fire spread, yet the extent of this effect is not well quantified in relation to other vegetation types. We examined the influence of aspen cover on interpolated daily fire spread rates, the relative abundance of aspen at fire perimeters versus burn interiors, and whether these relationships shifted under more fire-conducive atmospheric conditions. Our study incorporated 314 fires occurring between 2001 and 2020 in the southwestern United States and a suite of gridded vegetation, topography, and fire weather predictor variables. We found that aspen slows fire progression: as aspen cover on the landscape increased, daily area burned and linear spread rate decreased. Where aspen cover was <10%, daily fire growth averaged 1112 ha/day and maximum linear spread was 2.1 km/day; where aspen exceeded 25%, these values dropped to 368 ha/day and 1.3 km/day. Aspen also serves as a barrier to fire spread, demonstrated through a higher proportion of aspen cover at fire perimeters than in burn interiors. Finally, though favorable fire weather conditions increased fire growth rates, differences between aspens and conifers persisted. Our results affirm that aspen stands can act as a firebreak, with clear applications for vegetation management. For example, interventions that shift conifer to aspen cover could lessen the risk of fire for nearby values at risk (e.g., communities, infrastructure) but still support forest ecosystem function. Further, wildfire-driven conversion from conifer to aspen forest types in some landscapes may produce a negative feedback that could dampen expected increases in fire activity under a warmer and drier climate.
Tropical dry woodland loss in India since 1880 and its relation to current megafauna distributions.
Kalam T, Baumann M, Pötzschner F … +4 more , Reddy CS, Ghoddousi A, Roy PS, Kuemmerle T
Ecol Appl · 2025 Jul · PMID 40620030 · Full text
Tropical dry woodlands provide ecosystem services to hundreds of millions of people and support high biodiversity. Despite their importance, many dry woodlands are under high and rising human pressure, including in India...
Tropical dry woodlands provide ecosystem services to hundreds of millions of people and support high biodiversity. Despite their importance, many dry woodlands are under high and rising human pressure, including in India, where they provide essential habitat for iconic megafauna. However, there are notable gaps in our understanding of long-term changes in dry woodlands and how they relate to the present-day distribution of megafauna. Here, we reconstructed tropical dry woodland change since the 19th century, identified archetypes of change, and explored their relationship with current megafauna distributions. More specifically, we compared the reliability of existing satellite-based woodland maps and integrated them into an ensemble map of contemporary dry woodland cover in India. This allowed us to derive recent changes in dry woodlands since 1995 and, by integrating them with historical maps, long-term changes since 1880. Finally, we used non-parametric spatial clustering to detect typical patterns of long-term woodland change and compared these to the current distribution of 14 megafauna species. These analyses yielded four major insights. First, we show a massive historical loss of dry woodland cover in India since the 19th century, with over 22 Mha (equaling 65% of dry woodlands) lost, underscoring the threatened nature of these ecosystems. Second, we identified six archetypes of woodland change, three characterized by different levels of continuous woodland decline and three showing a forest transition pattern of historical decline, stability, and subsequent recovery. This highlights the regional variations in woodland dynamics across India's dry woodlands. Third, we found a strong and positive link between current megafauna distribution and high woodland cover, especially for threatened species (r = 0.43, p < 0.05), regardless of woodland histories, pointing to the importance of maintaining larger tracts of dry woodlands for safeguarding megafauna and for megafauna restoration potential where woodlands are recovering. Finally, we show that Indian dry woodlands are still undergoing widespread losses of 6.5 Mha since 1995, and pressure on them has been increasing recently. Therefore, better protection and monitoring of dry woodlands is urgently needed, and our analyses can provide a basis for context-specific land-use and conservation planning.
Environmental drivers of productivity explain population patterns of an Arctic-nesting bird across a half-century.
Piironen A, Knetter JM, Spragens KA … +9 more , Dooley JL, Patil V, Reed ET, Ross M, Gibson D, Behney AC, Petrie MJ, Sanders TA, Weegman MD
Ecol Appl · 2025 Jul · PMID 40611677 · Full text
Joint estimation of demographic rates and population size has become an essential tool in ecology because it enables evaluating mechanisms for population change and testing hypotheses about drivers of demography in a sin...
Joint estimation of demographic rates and population size has become an essential tool in ecology because it enables evaluating mechanisms for population change and testing hypotheses about drivers of demography in a single modeling framework. This approach provides a comprehensive perspective on population dynamics and how animal populations will respond to global pressures in future years. However, long-term data for such analyses are often limited in quantity and quality. We developed an integrated population model combining data on demography and population size from nine different sources to understand the population ecology of the lesser snow goose (Anser caerulescens caerulescens) in the Pacific Flyway in North America from 1970 to 2022. We divided the flyway population into Wrangel Island and Western Arctic subpopulations and assessed demographic mechanisms for population change and environmental and anthropogenic drivers that influenced demography. During 1970-2022, the estimated spring population of snow geese in the Pacific Flyway increased from ~300,000 to ~2,300,000. Short-term changes in population growth rate were primarily driven by changes in productivity in the Western Arctic and productivity and immigration in Wrangel Island. Changes in hunting and natural mortality had less influence on short-term but likely contributed to the pronounced long-term population growth. Early snowmelt positively influenced per capita productivity in both regions, and warm, rainy weather during the non-breeding season was associated with high per capita productivity in the Western Arctic. In the Western Arctic, per capita productivity was negatively associated with population size, and adult natural mortality was positively associated with population size, indicating density-dependent regulation in this subpopulation. In Wrangel Island, warm weather in early fall decreased juvenile natural mortality. Our results demonstrate that per capita productivity and immigration, rather than adult survival, were the primary mechanisms of short-term population change in this long-lived species. Our results also indicate that environmental conditions and density-dependent effects can impact population dynamics more than harvest, even for a long-lived, commonly harvested species. We demonstrate that a warming climate can have multiple effects on demography, emphasizing the importance of assessing a variety of spatial and temporal factors when predicting how populations might respond to large-scale environmental changes. This emphasizes the importance of conservation plans that consider these environmental drivers, although this may complicate direct management of such populations.
Measuring biological effectiveness across a very large, coherent network of coastal marine protected areas.
Spiecker B, Carr MH, Malone DP … +4 more , Parsons-Field A, Koehn K, Pondella DJ, Caselle JE
Ecol Appl · 2025 Jul · PMID 40611565 · Full text
We evaluated the performance of California's coastal marine protected area (MPA) network, the largest scientifically designed network of its kind, using SCUBA survey data from a large-scale, long-term kelp forest monitor...
We evaluated the performance of California's coastal marine protected area (MPA) network, the largest scientifically designed network of its kind, using SCUBA survey data from a large-scale, long-term kelp forest monitoring program. To comprehensively evaluate MPA performance, we employed multiple metrics across various scales of taxonomic and spatial aggregation and four key results emerged. First, population responses to MPAs varied greatly across the large network, whether evaluated as combined taxa or individual focal species or at single MPA or regional scales. Second, while responses varied widely, effect size analysis revealed differences in magnitude of MPA performance over time, with targeted species increasing or declining less within MPAs compared to non-targeted species in all regions except the North Coast. Third, average response ratios further supported these findings by providing a cumulative perspective on MPA performance. Specifically, 80% of MPAs showed positive response ratios for targeted species, with 12 of these cases being significant, indicating generally higher biomass inside MPAs. Finally, using our most conservative performance framework of divergence between MPA and non-MPA (Ref) sites and between targeted and non-targeted species, only the South Coast and Northern Channel Islands regions exhibited a significantly positive trend in biomass ratios (MPA/Ref) over time for targeted species. While biomass ratios increased significantly over time within MPAs for targeted species, divergence between targeted and non-targeted species' trends was largely absent, except in the Northern Channel Islands where a marginally non-significant effect was noted. Taken together, these results demonstrate that MPA performance is variable across regions and taxa, and different aspects of performance were revealed depending on the metric used. This underscores the need for comprehensive evaluation approaches when assessing the effectiveness of large, networked MPAs.
Species aggregation models resolve essential foraging habitat: Implications for conservation and management.
Santora JA, Suca JJ, Cimino M … +5 more , Hazen EL, Field JC, Bograd SJ, Wells BK, Schroeder ID
Ecol Appl · 2025 Jul · PMID 40605787 · Full text
Species aggregations are a culmination of behavioral events arising from an array of biophysical interactions, dynamically shifting in space and time. Prediction of species' aggregation dynamics remains a challenge in st...
Species aggregations are a culmination of behavioral events arising from an array of biophysical interactions, dynamically shifting in space and time. Prediction of species' aggregation dynamics remains a challenge in studies of their distribution patterns. Species distribution models (SDMs) are statistical tools for understanding spatial patterns of marine biodiversity, ranging from essential species habitat, assessing fisheries bycatch, and projecting future distribution changes. SDMs involving pelagic species abundance generally do not typically resolve aggregation patterns. We use a 20-year observation record of seabird species aggregations, with seabirds being the most easily quantified "pelagic" species, to develop SDMs and a regional ocean modeling system to identify physical drivers and changes in aggregation location and intensity over time. We apply a conceptual ecosystem model to organize environmental covariates according to habitat production within coastal upwelling systems. The SDM used a 2-step modeling approach: a presence/absence model and a binary aggregation model. Thus, we aim to predict factors that characterize baseline ocean habitat for a species (presence/absence) and that aggregate large numbers of the species. Prediction of seabird aggregation results in realistic spatial distribution patterns that reflect known species habitat associations. Temporally, aggregation indices indicate mixed responses both within and between resident and migrant species, reflecting interannual effects of warm/cool ocean years and mesoscale structure supporting enhanced or decreased productive foraging habitat. The most abundant species were more likely to form aggregations during warmer years, indicating a response to a decrease in productive foraging habitat. The occurrence of species aggregations in spring is predictable by examining ocean-climate conditions in the preceding winter, thus providing a potential early warning system of anticipated ecosystem shifts. We contend that the aggregation occurrence model may improve the realism of pelagic SDMs and their utility for assessing spatial and temporal variability of trophic interactions. We discuss the utility of species aggregation models for quantifying the variability in critical pelagic habitats, the ecology and response of seabird species as indicators, advancement of ecosystem modeling and monitoring, and conservation applications (e.g., bycatch, wind energy, and oil spills).
Facilitated migration could bolster migrant passage through anthropogenically altered ecosystems.
Burford BP, Notch JJ, Poytress WR … +1 more , Michel CJ
Ecol Appl · 2025 Jul · PMID 40605740 · Full text
Anthropogenic habitat change frequently outpaces the adaptive capacity of migratory taxa, placing many species and populations at risk of extirpation or extinction due to the mismatch of natural migration phenology and s...
Anthropogenic habitat change frequently outpaces the adaptive capacity of migratory taxa, placing many species and populations at risk of extirpation or extinction due to the mismatch of natural migration phenology and suitable conditions. While dynamic protection can greatly benefit migratory species, it is contingent on the flexibility of relevant management actions. For regulated ecosystems where advanced management planning is required, we present a new framework-facilitated migration-for actively matching natural migration phenology with suitable conditions for successful migrant passage. Using a case study of juvenile Chinook salmon (Oncorhynchus tshawytscha) oceanward migration in the Sacramento River, a major bottleneck to the recovery of imperiled populations in California, we show how the conditions associated with migration preparation, migration initiation, and successful migrant passage could be regulated to benefit migrants. Thermally shifted preparation, flow pulse-mediated initiation, and passage protection via increased flow, all accomplished by controlling the release of water from storage reservoirs, could increase the number of natural-origin Chinook salmon populations successfully migrating to the ocean by 43%-479% compared to the status quo management scenario. To further inform expected outcomes, we find that the temporal scope and diversity of juvenile salmon lifestages studied via acoustic telemetry should be expanded, and that the range of flows and flow changes that juvenile salmon experience should be increased. Facilitated migration works by synchronizing migration-thus, a prudent course of action when implementing this strategy would be to favor event quality over event quantity. In forcing scientists and managers to critically evaluate how migrations can be supported and manipulated, facilitated migration will help migratory species persist in anthropogenically altered ecosystems.
Landscape homogenization strengthens the fitness benefits of plant species' centrality in pollination networks.
Gómez-Martínez C, Cursach J, González-Estévez MA … +1 more , Lázaro A
Ecol Appl · 2025 Jul · PMID 40605554 · Full text
Understanding how plant-pollinator interactions vary along disturbance gradients and influence community function is essential to comprehend how pollination services can be maintained in increasingly anthropized landscap...
Understanding how plant-pollinator interactions vary along disturbance gradients and influence community function is essential to comprehend how pollination services can be maintained in increasingly anthropized landscapes. Recent studies found positive relationships between plant fitness and centrality in interaction networks (i.e., high proximity to other plants via shared pollinators). However, this relationship might vary depending on communities' landscape context and species' functional traits. We hypothesized that the fitness benefits of centrality might be higher in homogeneous landscapes than in heterogeneous landscapes, as the former might favor generalist species and behaviors. We also expected stronger positive relationships between centrality and fitness in pollinator-dependent actinomorphic species compared to autogamous species that do not depend on pollinators or zygomorphic species that are pollinated by a small set of specialized species. Here, we combined field samplings and experiments to study how centrality related to fitness (seeds produced) in 11 plant species from 20 communities along a gradient of landscape heterogeneity. For that, we assessed changes in the centrality-fitness relationship associated with landscape variations and species' functional groups: autogamous species, entomophilous-actinomorphic species, and entomophilous-zygomorphic species. We found that centrality positively influenced plant fitness in more homogeneous landscapes, whereas it had a null effect on fitness in more heterogeneous landscapes. Furthermore, centrality was irrelevant for the fitness of mostly autogamous plant species but influenced the fitness of mostly entomophilous species, increasing the reproductive output in actinomorphic species while decreasing it in zygomorphic ones. For the first time, we show that the relationship between interaction structure and function varies with the landscape context and the group of species evaluated. Our study also highlights the importance of conserving heterogeneous landscapes to maintain effective specialized interactions, as the higher fitness benefits of centrality in homogeneous landscapes might drive feedback cycles of increased generalization over time in communities within these landscapes.
Predator niche overlap predicts effects on aphid vectors and a vector-borne virus.
Lee BW, Basu S, Oeller L … +2 more , Northfield TD, Crowder DW
Ecol Appl · 2025 Jul · PMID 40605552 · Full text
Multiple predator species can enhance or disrupt prey suppression based on whether different predators forage in complementary or overlapping niches. Interactions between predator species are primarily evaluated by resul...
Multiple predator species can enhance or disrupt prey suppression based on whether different predators forage in complementary or overlapping niches. Interactions between predator species are primarily evaluated by resulting effects on prey abundance, although alterations of prey behavior also occur. When prey are vectors of plant pathogens, changes in their movement among plants may affect pathogen transmission as strongly as changes in vector abundance. Here, we assessed how single predator species, and pairs of species with varying degrees of niche overlap, affected pea aphid vectors and transmission of an aphid-borne pathogen, pea-enation mosaic virus (PEMV). Foliar-foraging predators reduced vector abundance but altered vector behavior in ways that promoted PEMV transmission, resulting in no net effects on PEMV prevalence. Predator pairings also enhanced vector suppression but caused vectors to move to parts of plants that were more susceptible to PEMV. Surprisingly, pathogen prevalence was only reduced in predator pairings that did not exhibit super-additive predation rates. Our study shows that enhanced predator consumption of vectors due to niche complementarity can affect pathogen transmission differently than it affects vector dispersal and feeding behaviors. Nonetheless, long-term suppression of vector populations may ultimately reduce pathogen transmission.
Limited tree mortality in unburned areas linked to bark beetle spillover from wildfires.
Andrus RA, Egan J, Ivy N … +4 more , Lowrey L, Naficy CE, Steed B, Meddens A
Ecol Appl · 2025 Jul · PMID 40605447 · Full text
Increased fire activity in the western United States since 2000 has produced an abundance of fire-injured trees at risk to lethal attack by bark beetles. Large populations of bark beetles reproducing in fire-injured tree...
Increased fire activity in the western United States since 2000 has produced an abundance of fire-injured trees at risk to lethal attack by bark beetles. Large populations of bark beetles reproducing in fire-injured trees may disperse (or spillover) from inside the fire perimeter to adjacent, unburned forests, potentially causing extensive tree mortality. In the western United States and Canada, fire-injured Douglas-fir (DF; Pseudotsuga menziesii) are frequently colonized by Douglas-fir beetle (DFB; Dendroctonus pseudotsugae), prompting concern among land managers about elevated risk of spillover. We investigated spatiotemporal patterns of DF tree mortality from DFB in unburned areas surrounding 61 wildfires (2000-2017) with a high likelihood for spillover in the Northern Rocky Mountains, USA. We developed a multiple-scale analytical framework to examine tree mortality potentially associated with spillover following fire. Synchronous fluctuation in the amount of DF mortality within and beyond the flight distance of DFB in the region and surrounding individual fires (0-10 km) suggested that DFB activity primarily responded to a broader scale process, such as drought, rather than proximity to burned trees. Using shorter and longer range dispersal scenarios, we estimated that at <0.25 km from the fire perimeter, the dominant source of DFBs transitioned from burned to unburned sources due to the closer proximity of DFBs from unburned sources. Some fires (8%-15%; range of fires from sensitivity analysis) did exhibit evidence of DFB spillover, but spillover occurred <1 km from fires (based on our criteria) and DF tree mortality associated with spillover was 0.2%-0.3% of total DF damage area during the study period. Spillover was not associated with climate conditions that increase host tree stress, rather it was associated with greater DF mortality from DFB in the prior year in the same area (i.e., poorly linked to spillover). Site-specific monitoring of post-fire DFB populations in susceptible, unburned DF forests adjacent to fires by land managers may be necessary to determine the risk of DFB emigrating from burned areas. Our findings inform post-fire planning and the ecological implications of disturbance interactions that occurred in the early 21st century during a period of amplified wildfire and DFB activity.
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