Ecological Applications
○ Wiley
Preprints posted in the last 90 days, ranked by how well they match Ecological Applications's content profile, based on 28 papers previously published here. The average preprint has a 0.02% match score for this journal, so anything above that is already an above-average fit.
Ward, E. J.; Anderson, S. C.
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Spatial and spatiotemporal models are increasingly critical for understanding species distributions, tracking population change, and informing conservation decisions. As biological processes are influenced by increasing external pressures, including human disturbance or environmental change, accurate model predictions become essential for adaptive management. However, the reliability of spatial predictions depends on often-overlooked modelling choices, including the spatial resolution used to approximate underlying processes. Using long term monitoring data from a large-scale groundfish survey in the California Current ecosystem, we investigated how spatial model complexity affects the quality of ecological predictions and derived indices used for management. We fit spatial and spatiotemporal models of ocean temperature and fish biomass density for 27 commercially important species using varying levels of spatial resolution. We evaluated both in-sample and out-of-sample prediction, and effects on area-weighted biomass indices. Counter to common assumptions, increasing spatial approximation resolution did not universally improve predictions. Our case studies demonstrate that for many datasets, out-of-sample prediction quality peaked at intermediate spatial resolutions and declined at the finest scales. Through simulation testing, we found this pattern was strongest when spatial patterning had a small range and high spatial variance, and observation error was low. For most species, spatial resolution had a minimal effect on biomass trend estimates used in management, but for several commercially important rockfish species, resolution choices substantially affected both the scale and uncertainty of population indices. Our findings demonstrate that spatial model specification can substantially affect ecological inference, with direct implications for management and conservation planning. We provide practical guidance for ecologists on selecting appropriate spatial complexity through cross-validation. When out-of-sample prediction is a focus, appropriate approximation complexity should improve both parameter estimation accuracy and derived quantities.
Gillies, G. J.; Dungey, M. P.; Eckert, C. G.
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O_LIChanges in habitat structure across species distributions may contribute to the generation and maintenance of range limits, but few studies have evaluated this by directly measuring habitat availability across relevant spatial scales. C_LIO_LIHere, we test the predictions that coarse-scale and patch-level habitat availability decline towards and beyond the northern range limit of Pacific coastal dune endemic Camissoniopsis cheiranthifolia. We used aerial imagery and geographic information system (GIS) tools to measure the coarse-scale availability of coastal dune habitat in California and Oregon. The availability of finer-scale habitat patches specifically suitable for C. cheiranthifolia was measured in a 2-generation field survey of > 4,200 5m x 5m plots randomly distributed across 1100 km of coastal dune habitat transcending the species northern range limit. At each plot, we estimated the proportion of area that contained suitable habitat as well as recorded occupancy by C. cheiranthifolia. As an alternative approach to visually estimating habitat suitability, we recorded plant community composition at each plot to predict beyond-range habitat suitability using a random forest model. C_LIO_LIContrary to our predictions, we found that coastal dune habitat, measured coarsely from aerial imagery, was more abundant and continuous towards and beyond the northern range limit. At the fine scale, however, the proportion of plots with suitable habitat (patch suitability) and the proportion of habitat within plots that was suitable (patch size) declined across the range limit. Moreover, patches were more isolated from one another and, in one survey year, less temporally stable towards and beyond the range limit. Finally, occupancy by C. cheiranthifolia was less likely in smaller, more isolated, and temporally unstable patches, providing mechanistic insight to the previously observed decline in occupancy towards the range limit. C_LIO_LISynthesis: Taken together, our results suggest that fine-scale habitat patch configuration changes in ways that likely impede patch colonization, thereby reducing occupancy and limiting the species northern distribution. Thus, consideration of geographic variation in patch and landscape structure, rather than only coarse-scale habitat availability, may be essential for understanding the processes that limit species ranges. C_LI
Saitou, M.; Chavarie, L.; Haugen, T.
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Marine protected areas (MPAs) are widely implemented to protect and/or rebuild exploited populations, yet their population-level effectiveness remains highly variable. Key unresolved knowledge gaps include how the size and the spatial placement of no-take zones interacts with larval dispersal directionality, particularly in linear coastal systems where connectivity is asymmetric. For sedentary species with planktonic larvae, such as European lobster, it is unclear under which dispersal regimes spatial configuration of protection critically determines positive demographic outcomes. Here, we address this gap using a spatially explicit individual-based model parameterized for the European lobster. We ask (i) whether no-take zones consistently enhance abundance and size structure relative to fished areas, and (ii) whether the positioning of no-take and open areas affects spatial protection while holding total protected area constant and (iii) how the alignment between larval dispersal direction and the positioning of no-take areas influences protection outcome. We contrast local, symmetric long-distance, and strongly unidirectional larval dispersal across alternative MPA layouts with equal total protected area but with different spacing. We show that no-take zones reliably increase abundance and the prevalence of large individuals. However, when larval dispersal is strongly unidirectional, population recovery depends on reserve placement: downstream no-take zones benefit from both larval import and local retention, whereas upstream reserves primarily export reproductive output and show limited local recovery. These results indicate that reserve performance cannot be evaluated independently of connectivity structure and identify dispersal directionality as a key determinant of when and where spatial configuration matters for MPA effectiveness in linear coastal systems.
Coroller-Chouraki, S.; Bush-Beaupre, A.; Savage, J.; Belisle, M.
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Intensive agricultural practices directly affect farmland bird and non-target insect populations by modifying their habitats, but may also act indirectly by altering their interactions. Notably, the breeding success of insectivorous birds has been shown to suffer from reduced prey availability. Yet little is known about how agriculture influences host-parasite relationships in wild birds. How agricultural intensity affects parasites, and whether this alleviates or exacerbates the trophic stress imposed on birds therefore remains to be determined. We estimated the number of obligate hematophagous Protocalliphora blowfly larva (Diptera: Calliphoridae) that parasitized nestlings in 2,560 Tree Swallow (Tachycineta bicolor) broods along a 10,200-km{superscript 2} gradient of agricultural intensity between 2004 and 2019 in Quebec, Canada. We first modeled two key variables along the causal paths expected to affect Protocalliphora prevalence and load (abundance) within infested broods: nestling hatching date and nestling host availability. Hatching phenology varied by several days with early-spring meteorological conditions and parental age, as for nestling availability (nestling-days), which also decreased along the agriculture intensity gradient as pastures and hay fields were replaced by large-scale, cereal row crops. Nestling availability peaked under low precipitation rates when temperatures reached 18 to 25 {degrees}C. Prevalence and load of blowfly larvae directly increased with nestling availability as well as with the temperature and precipitation that occurred during the larval development and pupation stages. Controlling for nestling availability, Protocalliphora prevalence and load peaked in forested landscapes interspersed by pastures and hay fields and reached their lowest in landscapes dominated by corn and soybean monocultures with minimal tree cover. Agricultural intensity thus reduced infestation likelihood and severity both directly and indirectly, by limiting nestling host availability. This finding is notable given the documented negative effects of agricultural intensity on fledgling number and body condition in farmland birds, even after controlling for insect prey reduction. If agricultural intensity indeed reduces the parasitic pressure exerted by bird blowflies and its consequences for fledgling condition and recruitment, this suggests that other agricultural impacts (e.g., toxicological effects from pesticides) may play a larger role than previously recognized in the severe declines of farmland bird populations observed across the Holarctic. Open research statementThe data supporting this study are not yet publicly available, as they require final harmonization, documentation and anonymization prior to archiving. Upon acceptance of the manuscript, all underlying data and associated code will be permanently deposited in the Zenodo repository and made fully accessible with a DOI.
Hopf, J. K.; Giraldo-Ospina, A.; Caselle, J.; Kroeker, K.; Carr, M.; Hastings, A.; White, J. W.
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Marine protected areas (MPAs) are increasingly promoted as climate mitigation tools, yet guidance on their placement to maximize resilience against climate stressors like marine heatwaves remains limited. Here, we develop MPA placement guidelines that explicitly consider a mechanistic pathway through which MPAs could enhance kelp forest resilience to heatwaves: protecting fishery-targeted urchin predators to prevent kelp overgrazing. Using a spatially explicit, tri-trophic model of California kelp forests, we evaluate alternative MPA configurations across a hypothetical coastline where half the habitat experiences an increased probability of experiencing heatwaves. We found that effective MPA placement depends on whether MPAs are being newly established or reconfigured within an existing network, and that among-patch connectivity and spillover played vital roles in the relative effectiveness of different MPA configurations. Changes in resilience occurred primarily at the patch scale, with trade-offs between increased within-MPA resilience and decreased resilience in some fished areas, resulting in minimal coastwide population effects. For example, for new MPAs, large single MPAs within heatwave-prone areas maximized within-MPA resilience gains, while multiple small MPAs in heatwave refugia best supported whole-coast resilience. When reconfiguring established networks, expanding existing MPAs in refugia areas was most effective. We also demonstrate the importance of considering MPA recovery timescales: for example, relocating old MPAs to heatwave refugia yielded minimal short-term benefits due to the loss of rebuilt, previously fished, predator biomass. Our findings demonstrate that climate-adaptive marine planning should explicitly consider the spatiotemporal implications of trophic cascades, connectivity, and transient population dynamics to support ecosystem resilience.
Heffernan, P. M.; Murdock, C. C.; Rohr, J. R.
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O_LIAlthough ecological research has long focused on the effects of temperature on population growth, arthropod pests are exposed to a wide variety of environmental factors that affect their performance, such as chemical pesticides targeted against them. Moreover, these environmental factors likely do not act in isolation. Identifying the extent to which abiotic factors interact to affect pest population dynamics can strengthen current and future pest management programs. C_LIO_LIHere, we investigated the extent to which temephos, a common pesticide applied to aquatic environments for mosquito control, influences the thermal performance of juvenile survival and development rate, as well as the intrinsic population growth rate, of the invasive mosquito pest, Aedes aegypti. We implemented a response surface experimental design to measure these traits across seven temperatures and five temephos concentrations and fit temperature- and insecticide-dependent performance curves to assess impacts on the overall performance and the thermal optimum, minimum, and maximum. C_LIO_LITemephos exposure profoundly altered the thermal performance of juvenile survival by reducing survival across all temperatures, shrinking the thermal breadth, and shifting the thermal optimum to warmer temperatures. Through this, temephos also altered the thermal performance of population growth primarily by reducing its thermal breadth. C_LIO_LISynthesis and applications: Our findings demonstrate that interactions between temperature and insecticide exposure can fundamentally reshape pest population dynamics, rather than acting as independent stressors. By quantifying this interaction, we showed that temphos is most effective below the pests thermal optimum, suggesting that larvicides may yield the greatest population suppression in cooler regions or during cooler periods of the year. Incorporating such temperature-dependent efficacy into pest management strategies could improve the timing and spatial targeting of control efforts. More broadly, these results highlight the need to integrate anthropogenic stressors with climatic drivers when predicting pest risk and optimizing management under ongoing environmental change. C_LI
Auger-Methe, M.; Dupont, F.; Eby, A.; Elliott, K. H.; Hussey, N. E.; Lyons, D. A.; Marcoux, M.; Patterson, A.; Shadloo, S.; Shuert, C. R.
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Habitat selection analyses, which discern the environmental conditions individuals select, often inform conservation planning. Through a literature review, we demonstrate that recent habitat selection studies rarely include fitness and health information. With a simulation study, we show that ignoring such information could support the protection of sink habitats. Our case studies demonstrate how health and fitness proxies can modify our understanding of habitat selection: (1) incorporating mass gain of thick-billed murres shows the energetic benefit of areas deemed secondary by a naive resource selection function; (2) including number of chicks in a step selection function (SSF) exposes the complex relationships glaucous-winged gulls have with landscapes impacted by humans; and (3) including external signs of trauma in the movement kernel of SSFs demonstrate others ways in which narwhal distribution can be altered. We urge movement ecologists to collect and use health and fitness data to improve ecological inference and conservation action.
Schille, L.; Poirier, V.; Raspail, F.; Chaumeil, P.; Bordenave, P.; Herrault, P.-A.; Paquette, A.
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Urbanization is a major driver of avian biodiversity loss, primarily through habitat fragmentation and the degradation of food resources, leading to the homogenization of bird communities that are often assumed to share increasingly generalist dietary traits. However, the interaction of urbanization gradients with local habitat features in shaping dietary adjustments remains poorly understood, both at the species and community levels, and it is unclear whether these adjustments reflect prey availability or active food preferences to meet energetic needs. We conducted a study across 25 plots distributed along a controlled urbanization gradient in Montreal, Canada. We quantified habitat variables at both landscape and local scales, sampled arthropod prey guilds, identified insectivorous bird communities using acoustic monitoring, and estimated their potential insectivory from trait-based approaches. In parallel, we assessed realized insectivory using cafeteria experiments offering three types of artificial prey (lepidopteran larvae, spiders, and ants), monitored with custom-built cameras developed specifically for this study to record bird-prey interactions. Along the urbanization gradient, we predicted that (i) functional diversity of bird communities declines and foraging-related traits converge toward more generalist strategies; (ii) profitable arthropod prey availability such as lepidopteran larvae decrease, while other guilds (e.g., Hymenoptera, Araneae) increase; (iii) realized insectivory increasingly diverges from potential insectivory; and (iv) food preferences vary due to both prey availability and active prey selection. We found a strong decline in avian biodiversity and in the availability of high-quality prey along the urbanization gradient, with a convergence toward generalist dietary traits. Yet, the avian biodiversity loss was buffered by canopy cover and tree diversity. Impervious surfaces, canopy cover, local vegetation cover, and lepidopteran abundance were key drivers of the composition of foraging communities observed at cafeterias. Interestingly, realized insectivory exceeded potential insectivory under high local vegetation cover, but the opposite pattern emerged in sparsely vegetated sites. Attack probability on larvae models increased with impervious surfaces, whereas attacks on ants decreased with tree diversity, suggesting active selection of nutritionally profitable prey independent of actual prey availability. Overall, our results highlight the critical role of small, unmanaged vegetation patches, alongside larger and structurally diverse canopy-covered areas, in sustaining avian biodiversity and insectivory functions in cities.
Hu, J.; van Os, D.; Morpurgo, J.; Veldhuis, M. P.; Remme, R. P.; de Snoo, G. R.; Si, Y.
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Urban expansion drives land cover change and habitat simplification, contributing to biodiversity loss. Urban green spaces can mitigate these impacts, but their effectiveness depends on its configuration and implementation. Here, we examine how three complementary dimensions of environmental heterogeneity--plant species richness, habitat heterogeneity, and foliage-layer richness--shape bird richness along an urbanisation gradient in the Netherlands. Using bird and plant occurrence data, LiDAR-derived vegetation structure, and land-use data, we fitted generalized additive models at three spatial scales (100, 200, and 300 m) to assess how these relationships vary across the urbanisation gradient. Plant species richness showed the strongest and consistent positive effect on bird richness, disregarding urbanization intensities. Habitat heterogeneity showed most pronounced positive effects at intermediate levels of urbanisation. In contrast, foliage-layer richness had weak associations with bird richness across urbanization intensities. Together, these results demonstrate that sustaining urban bird diversity requires urbanisation-intensity-dependent design of green-space heterogeneity. Increasing plant richness is generally recommended across urbanization intensities. Increasing habitat heterogeneity is more effective at intermediate levels of urbanisation and appears less suitable in highly urbanised contexts. Beyond simply expanding green space area or their spatial complexity alone, urban planning should focus on the thoughtful design of different types of environmental heterogeneity. This includes city-wide species-rich planting and structurally diverse habitat mosaics in mid-density areas to sustain urban bird diversity.
Lagerveld, S.; de Vries, P.; Rakhimberdiev, E.; Harris, J.; Noort, B. C. A.; Geelhoed, S. C. V.; Van Langevelde, F.; Mathews, F.; Poot, M.; Karagicheva, J.
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O_LICurtailment of wind farms effectively reduces collision mortality in bats. Implementing this measure in offshore wind farms requires knowledge on the spatiotemporal occurrence and environmental predictors of migration over sea. In bats, such information can be obtained through acoustic monitoring and individual tracking. However, these techniques provide seemingly contradictory insights into migration patterns. C_LIO_LIWe used a Bayesian capture-recapture state-space model to investigate how environmental predictors influence spring departure decisions of Nathusius pipistrelle Pipistrellus nathusii migrating over the North Sea. The model was applied to both acoustic and tracking data, enabling comparable analyses across methods and incorporating uncertainty in migration dates of tracked bats. Additionally, we examined nightly offshore bat occurrence to further explore differences in movement patterns detected by the two techniques. C_LIO_LIWind conditions at 200 m above sea level were identified as key driver of Nathusius pipistrelle spring migration. In May-June, most bats migrated from the United Kingdom under westerly and northwesterly tailwinds. Tracked individuals flew in stronger supportive winds than acoustically recorded bats, which were also detected under crosswinds and headwinds. In March-April, acoustic detections occurred mainly during strong southerly winds, suggesting that early-season migrants largely consisted of individuals migrating over the European mainland and drifted northwards onto the North Sea by strong crosswinds. C_LIO_LIAcoustic detectors primarily recorded bats that landed on offshore platforms, likely because they were unable to cross the North Sea in a single flight due to less favorable wind conditions, or because they departed from more inland locations. In contrast, tracking data mainly represented bats that successfully crossed the North Sea in a non-stop flight under moderate supportive tailwinds. C_LIO_LISynthesis and applications: Combining observation techniques improves our understanding of bat migration patterns. Additionally, acoustic monitoring can capture migration from different geographic origins. Current mitigation measures for offshore wind farms at the North Sea rely solely on acoustic data, likely overlooking the part of the population that crosses over sea with optimal wind support. Acoustic and tracking data are therefore complementary rather than contradictory, and both methods should be used together when developing mitigation measures. C_LI
Dimitriou, A.; Gaynor, K. M.; Benson-Amram, S.; Percy, M.; Burton, C.
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Humans are profoundly reshaping the natural world. These changes are giving rise to complex and mutually risky dynamics between people and large carnivores. In protected areas across North America, bears (Ursus sp.) face rapidly rising recreation pressures that can alter their use of the landscape, either displacing them from high-quality habitats or drawing them into human-wildlife conflicts through habituation or attraction to anthropogenic resources. However, disentangling responses to recreation from other drivers can be difficult because human activity covaries with environmental and seasonal processes that also shape bear activity. We leveraged the partial closure of the popular Berg Lake Trail in Mount Robson Park, British Columbia, Canada, to investigate whether black (Ursus americanus) and grizzly bears (Ursus arctos) showed fear, attraction or neutral behavioural responses to varying recreation levels across multiple spatiotemporal scales. To understand both anticipatory responses to predictable patterns of human activity, and reactive responses to hiker events, we used detections from 43 camera traps over two years (July 2023-June 2025). We compared weekly habitat use, daily activity patterns, and direct responses to hikers (using Avoidance-Attraction Ratios; AARs) among camera sites and between open and closed sections of the trail. Our results revealed that both bear species exhibited patterns consistent with fear responses, while some black bear behaviours were also consistent with attraction responses. Both kinds of responses reflect anticipatory strategies rather than reactionary behaviours (i.e., no AAR effect). Neither species avoided recreation spatially at the weekly scale: black bears were detected more at site-weeks with greater recreation intensity, while grizzly bears were consistently detected more at sites closer to hiking trails. However, both species used daily temporal partitioning to avoid direct encounters with humans. These findings demonstrate scope for human-bear coexistence when recreation levels are managed to be moderate and predictable, and bears have sufficient space to segregate from humans during peak times. Thus, successful coexistence will hinge on co-adaptation by both bears and people. Understanding how recreation influences bear behaviour, and the spatiotemporal scale at which that occurs, is critical for guiding effective adaptive management aimed at fostering human-bear coexistence in high-traffic protected areas.
Treminio, R.; Webb, N. P.; Edwards, B. L.; Newingham, B. A.; Garbowski, M.; Brungard, C.; Dubois, D.; Faist, A.; Kachergis, E.; Houdeshell, C.-A.
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Restoration of degraded areas and post-disturbance rehabilitation after wildfire encompass critical approaches for reducing and reversing impacts of wind erosion and sand and dust storms (SDS). However, the broad outcomes of dryland restoration and rehabilitation for wind erosion and SDS remain underexplored. Wind erosion is an emerging issue in the Great Basin of the western United States, exacerbated by invasive annual grasses and associated wildfire. Here, we assess potential wind erosion and SDS responses to wildfire, restoration, and post-wildfire rehabilitation treatments at the regional scale in the Great Basin. We used 13 years of rangeland monitoring data, the Aeolian EROsion model, and the Land Treatment Digital Library to produce counterfactual model-predictions to estimate treatment effects. Our results revealed reductions in aeolian sediment fluxes (Ln Q < 0 g m-1 d-1) across wildfire-affected regions (mean {+/-} SE: -0.070 {+/-} 0.077 Ln Q), restoration treatments in unburned areas (range: -0.867 {+/-} 0.398 to 0.480 {+/-} 0.253 Ln Q), and post-wildfire rehabilitation (range: -0.821 {+/-} 0.183 to 1.278 {+/-} 0.909 Ln Q). In particular, aerial seeding and soil disturbance restoration treatments, and post-wildfire closure-treatments had higher perennial grass cover and the most decreased Ln Q compared to untreated controls. These results represent an important regional scale assessment of wind erosion responses to restoration and post-wildfire rehabilitation. Our findings underscore the application of integrating wind erosion and SDS mitigation into restoration and post-disturbance rehabilitation programs to provide land managers with strategies to reduce land degradation while fostering ecosystem resilience.
Koehl, M. A. R.; Hadfield, M. G.
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Many benthic marine invertebrates disperse by releasing microscopic larvae carried by ocean currents to new sites, where they must settle into appropriate habitats and metamorphose to recruit. Species whose larvae settle in response to water-borne chemical cues live in topographically complex habitats. To study whether sinking in response to dissolved cues affects retention of larvae within complex habitats exposed to ambient water flow moving faster than larvae sink, we used the reef-dwelling sea slug, Phestilla sibogae, whose competent larvae stop swimming and sink in response to dissolved cue from their prey coral, Porites compressa. We conducted field experiments where dye-labelled water, neutrally buoyant particles, and larval mimics (particles that sank at the velocity of larvae of P. sibogae) were released together upstream of reefs of branching corals to determine if larval sinking in water above and within a reef affects larval retention within the reef. Wave-driven water flow measured above a reef in the field had instantaneous velocities peaking at 0.3 m s-1, driving slow net advection of water shoreward at [~]0.02 m s-1. Much slower wave-driven flow moved through the interstices within the reef. In this field flow, sinking by larval mimics caused their retention within a reef after dye-labelled water and neutrally buoyant particles had left. Such retention of sinking larvae within topographically complex benthic communities enhances successful recruitment by exposing larvae to high concentrations of cue for long periods, allowing them time to sink to surfaces, adhere, and undergo metamorphosis.
Nieuwenhuis, B. O.; Turlier, C.; Ciocanaru, I.-A.; Blaschke, B. A.; Kheireddine, M.; Leurs, G.; Cochran, J. E. M.; Govers, L. L.; Jones, B. H.
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Habitat partitioning supports the coexistence of sympatric species and shapes their ecological roles across coastal seascapes. Understanding how sympatric species move through and use coastal habitats therefore provides fundamental ecological insight. Aerial drones provide new opportunities to monitor fine-scale movement and habitat utilisation of elasmobranchs in shallow waters. Here, we use drones to investigate fine-scale habitat partitioning and foraging behaviour among stingrays in a coastal lagoon in the central Red Sea. We conducted 30 aerial transect surveys (~17 ha each) and tracked 40 rays and 1 shark (total tracking time > 23 h). Using a double-observer protocol (manual + AI-assisted), 1,468 rays (6 species) and 4 sharks (2 species) were recorded from the transect surveys. Transect detections were dominated by bluespotted ribbontail rays (Taeniura lymma; n = 1,221) and larger-bodied whiprays (predominantly Himantura uarnak; n = 187). AI-assisted image analysis outperformed human analysts detecting 97% of these observations, compared to 76% for human analysts. We found pronounced habitat partitioning at sub-kilometre scales: bluespotted rays occupied the shallowest (< 0.4 m deep) lagoonal areas, away from open water, with foraging-related digging concentrated along the mangrove edge, identifying this zone as a key feeding ground and bioturbation hotspot. Whiprays predominated on macroalgal reef flat habitats and appeared to forage non-disruptively on epifaunal prey. Both taxa aggregated with conspecifics. Together, our results demonstrate that contrasting micro-habitat preferences and foraging strategies structure the spatial ecology of sympatric stingrays and highlight how drone-based monitoring coupled with AI can scale ecological inference in nearshore ecosystems. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/710512v1_ufig1.gif" ALT="Figure 1"> View larger version (63K): org.highwire.dtl.DTLVardef@1cefdd9org.highwire.dtl.DTLVardef@7bc807org.highwire.dtl.DTLVardef@895540org.highwire.dtl.DTLVardef@3c146b_HPS_FORMAT_FIGEXP M_FIG C_FIG
Langdon, W. B.; Fox, R.; Lewis, O. T.
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O_LIAbundance of insect herbivores often depends on host plant suitability for their specialised immature stages. Suitability can be strongly influenced by both microclimate and the nutritional quality of the plants themselves. Where soil nitrogen is high, host plants tend to have high nutritional quality, but vigorous growth of surrounding vegetation reduces microclimatic temperatures. Thus, thermophilous insects may face a choice between host plants with optimal microclimates and those with optimal nutritional quality. C_LIO_LIWe investigated how microclimate and nitrogen content influence oviposition choices by the declining Small Copper butterfly, Lycaena phlaeas, on its host plant, Rumex acetosa. We predicted that warmer plants would have lower nitrogen content, and that butterflies would choose cooler, high-nitrogen plants during warmer ambient conditions. C_LIO_LIAlthough warmer R. acetosa plants had lower nitrogen content, L. phlaeas consistently chose to lay eggs on plants in warm microclimates, implying a trade-off between temperature and the nutritional quality of host plants. C_LIO_LIPatches of bare ground created by Talpa europaea (European Mole) near R. acetosa plants increased microclimatic temperatures and decoupled the negative correlation between nutritional quality and thermal suitability. C_LIO_LIOur results have implications for the conservation of thermophilous insect herbivores, especially close to their range margins and in the context of climate change. Rather than maximising host plant abundance or nutritional quality, management that creates suitable microclimatic conditions is likely to be critical. Our findings also suggest that, while nitrogen pollution may increase host plant nutritional quality, its negative impacts on microclimate will likely further reduce breeding habitat for L. phlaeas and other insects in grassland habitats. C_LI
Kochanski, J. M.; McFarlane, S. L.; Damschen, E. I.; Gratton, C.
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IntroductionHuman land-use intensification and the resulting habitat loss are primary drivers of insect pollinator declines. Habitat restoration offers a promising approach to counteract these declines, yet landscape-level evaluations of bee responses to restoration and management remain limited. We conducted a two-year, landscape-scale study in Wisconsin, USA, to assess how different intensities of tallgrass prairie restoration and management affect bumble bees (Bombus spp.). ObjectivesThis study aimed to determine whether (1) bumble bee abundance and diversity increase with assisted restoration, and (2) outcomes differ between low-(seeded only) and moderate-intensity (seeded and managed with prescribed fire) interventions. MethodsUsing catch-and-release surveys, we measured bumble bee abundance and diversity at 32 sites representing a gradient in restoration intervention: no intervention (unassisted recovery), low intervention, and moderate intervention. ResultsBumble bee abundance and diversity were higher at assisted restoration sites (low and moderate intervention) than at unassisted sites. Although both tended to be greater at moderate than low intervention intensities, these differences were not statistically significant. Bumble bee community composition also differed across intervention intensity, driven by shifts in dominant species (e.g., B. impatiens and B. griseocollis). Rarer taxa, including endangered and vulnerable species, occurred only at assisted restoration sites, with the largest populations at moderate intervention sites. Across all sites, bumble bee responses were strongly and positively associated with floral abundance, but not with semi-natural habitat in the surrounding landscape. ConclusionOur findings demonstrate that assisted grassland restoration can effectively increase bumble bee abundance and diversity, supporting its value as a conservation practice for pollinators. Implications for Practice: (1) Grassland restorations targeting plant communities can successfully support nontarget pollinators across a range of management intensities and landscape contexts. Adding seeds of pollinator-preferred plants could improve restorations with low floral abundance and diversity. (2) Management of existing restorations is important to maintain abundant floral resources and diverse pollinator communities. Because sites varied widely in prescribed fire use, our findings likely represent a conservative estimate of its benefits, and higher intervention intensity (e.g., repeated seeding, regular fire, mechanical or chemical shrub and invasive plants control) may further enhance outcomes for bumble bees.
Chiew, L. Y.; Jahuri, Y.; Rizan, S.; Chung, A. Y. C.; Japir, R.; Priyadarshana, T. S.; Slade, E. M.
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The rapid expansion of oil palm plantations in Southeast Asia has caused extensive deforestation and landscape fragmentation. Riparian buffers (vegetated strips along the edges of rivers) have been shown to enhance biodiversity, water quality, and erosion control. However, plantation managers have raised concerns that these buffers may harbour pests such as nettle caterpillars, bagworms, and rhinoceros beetles (Oryctes rhinoceros). These pests damage the palms and facilitate the spread Ganoderma boninense (a fungal pathogen). Using causal inference modelling we examined how riparian buffer characteristics (width and habitat quality), oil palm age, and surrounding landscape features influence pest and disease incidence in oil palms adjacent to riparian areas in Sabah, Malaysian Borneo. We surveyed 47,500 palms for pest and disease damage and used mark-release-recapture techniques to track O. rhinoceros movements in oil palms adjacent to riparian buffers. Most O. rhinoceros activity (66.30%) occurred within the plantations, and only 6.10% occurred within riparian buffers, with limited movement between habitats. Oil palm age was a dominant driver of pest attacks: young palms were more susceptible to lepidopteran caterpillars and O. rhinoceros, whereas G. boninense was more prevalent in mature palms. Neither the surrounding forest cover nor the quality of the riparian buffer affected the incidence of pest attacks. Riparian buffer width increased O. rhinoceros attacks, reduced G. boninense infection, and had no effect on lepidopteran caterpillars, highlighting that surrounding forest cover and riparian buffers do not drive pest attacks in oil palm plantations. Instead, management of oil palms within the buffers s is likely to be more important in managing pests; increases in invasive oil palms within the buffers increased the incidence of caterpillar damage, and higher numbers of remnant old oil palms increased O. rhinoceros attacks in adjacent oil palms. Overall, riparian buffers were found to contribute little to pest spillover, suggesting that their biodiversity and connectivity benefits outweigh minor pest risks, especially if invasive young and remnant old oil palms within the buffers are effectively managed and native vegetation restored.
Coverley, A. J.; Sheldon, K. S.; Marshall, K. E.
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O_LIEctotherms in thermally variable environments mediate energy expenditure through both physiological and behavioural responses. However, many studies focus on constant temperature acclimation, and few consider behaviour and physiology in unison. It is unclear how acclimation to thermal variability affects locomotory choices, activity timing, and performance across daily thermal cycles. C_LIO_LIWe investigated the effects of thermal variability in the temperate dung beetle Onthophagus taurus. Following acclimation to a low amplitude (22{degrees}C {+/-} 2{degrees}C) or a high amplitude (22{degrees}C {+/-} 10{degrees}C) temperature regime, we measured behaviour and metabolic rate across temperatures. We hypothesised that O. taurus adjusts its locomotive strategy and search window when kept in high amplitude fluctuating temperatures to reduce energy loss associated with high temperature exposure. C_LIO_LIWe found that differences in energy expenditure were determined by propensity for flight which differed between acclimation treatments, particularly at intermediate temperatures. We also found that, following acclimation to a high amplitude of thermal variability, O. taurus exhibited a greater intensity of activity over a narrower window of time, and O. taurus acclimated to a low amplitude of thermal variability showed nocturnal activity. C_LIO_LIWe then used the data to model activity through the growing season over five years. Biophysical models were built using NicheMapR Microclimate and Ectotherm functions to test the length of potential searching time across seasons, the temperatures individuals are exposed, and locomotive strategy. Model outputs showed that acclimation to higher amplitudes of thermal variability increased accumulated degree-hours of activity relative to the low variability acclimation group. Individuals acclimated to higher amplitudes of thermal variability showed greater accumulated degree-hours in spring and fall, but exhibited shorter periods of activity during summer, with the model predicting increased opportunities for flight. Comparatively, O. taurus from the low variability acclimation treatment showed increased night activity in summer but did not fly. C_LI
Painkow Neto, E.; Silvius, K. M.; Barquero, G.; Neves, D. C.; Fragoso, J. M. V.
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Animal population control is widely used to mitigate conflicts between wildlife and agriculture worldwide. Structured, monitored removals are rare in South America, however, and their consequences for wildlife populations as well as their effectiveness in reducing crop damage are little understood. Using eight years of data from an experimental white-lipped peccary management program in an agricultural mosaic in the Brazilian Cerrado biome, we assess how structured, non-lethal removals affect both peccary demography and second-crop corn damage. Leslie removal models based on 6,619 captured individuals indicated that cumulative removals to approximately 85% of the initial population strongly reduced peccary abundance, with limited demographic compensation despite fluctuations in reproductive output. Corn crop damage, quantified with satellite imagery, declined over time and was correlated with peccary population size. Interannual variation in population growth and juvenile recruitment was poorly explained by climate, fire, or landscape composition. Source-sink dynamics likely play a role in maintaining healthy populations at the regional scale. Together, these results demonstrate that sustained and monitored ungulate removals can reliably reduce population size and agricultural damage, supporting coexistence between wildlife and food crop production in human-dominated tropical landscapes.
Bartl, J.; Berthelsen, A. L.; Winterl, A.; Fox-Clarke, C.; Forcada, J.; Nagel, R.; Hoffman, J.; Fabry, B.
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Population density can influence individual predation risk in colonial breeders through shared vigilance and predator deterrence. We investigated how predator-prey interactions are shaped by population density at two Antarctic fur seal (Arctocephalus gazella) breeding colonies at Bird Island, South Georgia, which differ four-fold in seal density. By deploying autonomous time-lapse cameras, we captured high-resolution images at one-minute intervals throughout the breeding season. Using a YOLOv8 neural network, we identified fur seal adult males, females and pups, as well as three predator-scavenger bird species: giant petrels (Macronectes spp.), brown skuas (Stercorarius antarcticus) and snowy sheathbills (Chionis alba). Abundance patterns corresponded to the known foraging and breeding behaviours of these species. Differences in seal density between the colonies were mainly driven by adult females and their pups, but not adult males. The ratios of predatory birds to pups were markedly lower at the high-density colony, while scavenger to pup ratios remained similar. Spatial analyses revealed that predators were largely excluded from areas of high seal density, whereas scavengers overlapped extensively with pups in both colonies. This study demonstrates the value of remote observation in resolving predator-prey interactions and illustrates how density can shape predation risk in a colonial breeder.