Ecosphere

When measuring the impact of continuous independent variables, regressions are the appropriate tool. Regression experiments in ecology typically follow a replicated uniform design with experimental units evenly spaced across the design space. While popular, uniform designs are often inefficient and waste precious experimental resources. Optimal designs maximize the information gained per experimental unit and have been shown to be more efficient than uniform designs. However, optimal designs are parameter-dependent for non-linear regressions, which limits their application. Bayesian optimal designs use prior distributions of the parameters to calculate designs that optimize properties of the posterior distribution. Thus, they circumvent the parameter dependence and result in robust, efficient experimental designs. In this study, we developed Bayesian optimal designs with four different sample sizes for four common single-driver non-linear regressions measuring per-capita growth against nutrient concentration, light intensity, temperature and toxin concentration. We compared the optimal designs to corresponding uniform designs in terms of parameter inference and predictive ability. For parameter inference, we performed 1000 simulations for each function where we generated data through both designs and fit the model through Bayesian inference. We compared the resulting posteriors from each design using strictly proper scoring rules. We also used the median curves from each posterior to compare predictive ability across the design space. We found that optimal design broadly outperformed uniform designs in both parameter inference and predictive ability across all sample sizes, especially in the nutrient and toxin experiments. We thus demonstrated the superiority of Bayesian optimal designs over commonly used uniform designs and advocate for increased use of Bayesian optimal designs in ecology.

Coastal wetlands of the Laurentian Great Lakes support abundant populations of fish, invertebrates, and vegetation, though the trophic linkages connecting primary production and lower consumers is not well understood in these systems. We implemented a multiple-tracer approach to evaluate trophic pathways, pairing traditional food web isotope tracers like carbon ({delta}13C) and nitrogen ({delta}15N) with total mercury concentrations (THg). We predicted that filamentous algae would be the dominant energy resource in the diet of lower trophic-level invertebrates in the Grand River Estuary, a network of riverine coastal wetlands adjacent to Lake Michigan. In addition, we predicted that adding THg as a tracer would improve the resolution of our food web models by clarifying trophic levels and relationships between wetland species. Four basal energy sources were sampled, including filamentous algae, emergent macrophytes, submersed macrophytes, and phytoplankton, along with organic detritus. Aquatic invertebrates were sampled across multiple functional guilds to represent primary and secondary consumers and included amphipods and odonates. Our findings suggest that organic detritus is the dominant resource responsible for energetically supporting these lower trophic levels in the Grand River estuary, although submersed macrophytes were important alternative energy sources for secondary consumers. THg concentrations enhanced the resolution of dietary contribution estimates in MixSIAR models applied to consumer and source data. Isotope biplots revealed that THg concentrations were a more reliable predictor of trophic position than {delta}15N in Grand River Estuary (GRE) sites. This methodology has important implications for future food web studies in complex ecosystems such as coastal wetlands and demonstrates the novel use of mercury as an ecological tracer in a Bayesian mixing model approach.

Understanding the relationships between soil macrofauna and decomposition is crucial for predicting how land-use change impacts ecosystem function in fragmented systems. This is because soil macrofauna affect decomposition and also respond to the changes in abiotic conditions across habitat gradients. This study investigates edge effects on the macrofauna contributions to decomposition across forest-field ecotones. We used bait lamina assay to quantify aboveground and belowground feeding activity of soil macrofauna in Autumn 2025 in three deciduous forest-old field ecotones and one coniferous forest-old field ecotone, in Southwestern Ontario, Canada. Vegetation diversity and composition, LAI and soil characteristics (i.e., soil organic matter, pH, temperature and moisture) were measured at each plot along the ecotone. Pitfall trap data collected in Summer 2025 at the same sites were used to characterize macrofauna communities. We used generalized linear mixed effects models to estimate the effect of distance to edge, site, and depth into the soil on bait lamina consumption and soil macrofauna, with transect nested within site as random effects. Consumption activity increased with distance into the forest from the field, with the edge representing an intermediate; and, decreased with increasing depth into the soil. In contrast, soil macrofauna abundance, especially isopods, decrease with distance into the forest from the field. These trends varied significantly across sites, so that consumption activity and abundance sometimes remained constant across the ecotone (i.e., site x distance interaction). The results demonstrate that macrofaunal contributions to bait consumption varied along the ecotone, shaped by interacting environmental gradients and shifts in community composition unique to each site.

The Intermountain West of the United States has experienced years of extreme drought and increased temperatures. Increasing temperature and droughts can negatively impact native species that are locally adapted to environmental conditions that have persisted prior to the Anthropocene. Bees, especially solitary bees, provide critical ecosystem services because they pollinate ~90% of all flowering plants. Here we asked how drought impacted the reproduction of Osmia bruneri, a solitary mason bee. We released 20 females in nesting blocks at 21 field sites across four years (2020 - 2023) in the Bear River Mountains of northern Utah. O. bruneri reproduction was positively correlated with winter precipitation, and sex ratio was skewed in years that had a yearlong drought from the expected female to male ratio of 1.3:1 to 0.33:1. These results suggest that O. bruneri is susceptible to winter precipitation droughts. Not only was there a decrease in the total number of cells provisioned but the overall number of females produced decreased significantly during season long drought conditions. Continuous droughts can lead to a local level population decline and could contribute to overall species declines. Identifying the effects of extreme drought on solitary bee fecundity is critical for supporting effective management practices and conservation prioritization. Additionally, the results suggest that preceding winter precipitation can act as an indicator for predicting nesting success in wild solitary bees and may be an overall indicator of habitat quality.

Plant roots are broadly colonized by endophytic fungi with saprotrophic capabilities, but our understanding of whether they function in ways that are beneficial or detrimental to the host remains limited to model organisms. We hypothesized that endophytic fungi broadly affect plant access to soil nutrients, particularly organic forms that are typically not directly available to the plant. To address this, we paired 41 fungal endophytes with switchgrass (Panicum virgatum L.) and provided either inorganic or organic forms of nitrogen (N) and phosphorus (P). We evaluated how the fungi affected plant tissue N and P as well as plant growth. We also examined if these outcomes could be predicted from fungal phylogenetic relationships, in vitro traits of the fungi, or characteristics of the habitat from which fungi were isolated. There was substantial variation in both plant N (0.05-0.63%) and P (0.02-0.10%) acquisition that depended on the interaction of fungus and nutrient treatment. More fungi were beneficial for plant N than for P and shoot nutrients generally increased more than root nutrients from fungal associations. However, fungal effects on plant nutrients were not predicted by fungal traits, habitat traits, or fungal phylogenetic relationships. This unpredictability highlights a key challenge for incorporating endophytes into nutrient management strategies. Improving our ability to predict endophyte impacts on host nutrient acquisition will require identifying the mechanisms underlying observed beneficial effects and scaling up to realistic, diverse root microbial communities.

QuestionsEcological monitoring, repeated collection of ecological data, is essential to document how ecosystems respond to change. In grasslands, different vegetation monitoring protocols are used across disciplines, making it difficult to address multiple management objectives or research questions. We asked four questions about how three common vegetation monitoring protocols compare. (1) How do the protocols differ in how they collect data? (2) How do the protocols differ in their utility? (3) In what ways do vegetation measurements quantitatively differ across protocols? (4) What are each protocols strengths? LocationThis study was conducted on working ranches in the Southern Great Plains with vegetation consisting mainly of native forbs and grasses. MethodsWe implemented three protocols at each site: (1) the Rangeland Analysis Platform (RAP), (2) the Grassland Effectiveness Monitoring (GEM) protocol, and (3) a typical pollinator ecology survey protocol. We qualitatively compared each protocols utility and quantitatively compared cover measurements that each produced. ResultsAll three protocols displayed positive associations within cover categories, but differed in actual cover measurements. The RAP protocol, which uses remote sensing, measured the highest total vegetation cover. The GEM protocol, a line-point intercept method, had more capability to capture fine-scale cover patterns. The GEM protocol measured the most bare ground while the Pollinator protocol measured more forb coverage. ConclusionFine-scale methods like the GEM protocol are most appropriate to address objectives that require capturing small patterns that would otherwise be overlooked with methods like quadrats or remote sensing. Remote sensing is advantageous when monitoring large areas or inaccessible land, but may over-estimate cover. The Pollinator protocol is best equipped to address questions regarding flower abundance and richness. Similarities among protocols can facilitate synergy across disciplines for more effective monitoring. We emphasize the importance of denoting a clear scale and scope of monitoring objectives before selecting methods.

Urban pollinator gardens can provide refugia and support diverse populations of native bees amid threats from habitat destruction, pesticides, and potential ecological pressures from the introduced honey bee (Apis mellifera (Linnaeus, 1748)). The University of California, Berkeley, maintained a native bee garden at the Oxford Tract research facility to study the biodiversity, phenology, and foraging habits of urban bees from 2003 to 2009. That garden was decommissioned, and a new garden was re-established in 2019. Using diversity observations from the early 2000s garden and non-lethal sampling techniques, we characterized plant-pollinator interactions between flowers and urban bees in the newer bee garden with a bipartite interaction network. Across 12 flower species, we observed two non-native pollinators, the honey bee (A. mellifera) and the alfalfa leafcutter (Megachile rotundata (Fabricius, 1793)), along with at least ten native bee species across three families (Apidae, Halictidae, Megachilidae). We found that, despite the garden being created for native bees, honey bees accounted for 84% of all pollination interactions. The most abundant native bees were sweat bees (Family: Halictidae). Generalist interactions dominated the network, as both honey and sweat bees foraged on most available flowers. Honey bees showed a significant positive correlation with floral abundance, visiting flowers with the highest number of inflorescences, whereas native bees did not show this preference. These results indicate that native bee garden stewardship could benefit from greater floral diversity, while avoiding the dominance of any single species with high floral abundance, thereby reducing the likelihood of direct competition with honey bees.

Nutrient availability, ecosystem productivity, and consumer assemblages are intricately linked through complex interactions and feedbacks. Nutrients influence the diversity and functional roles of consumers via shifts in resource quality and quantity, and consumers can alter ecosystem production and nutrient availability. However, our understanding of how characteristics of consumers respond to and influence concomitant shifts in nutrient availability and production is limited. We quantified the response of well-studied consumer assemblages (benthic invertebrates and zooplankton) to realistic nutrient loads that altered gross primary production (GPP) and ecosystem respiration (ER). We fertilized 14 outdoor experimental ponds for 2 months and monitored total water column carbon (TC), nitrogen (TN), and phosphorus (TP), GPP, ER, and net ecosystem production (NEP) weekly. Then, we evaluated how fertilization and the variation in nutrients and metabolism caused by fertilization were related to shifts in consumer assemblages. Fertilization increased water column TN and TP and reduced TC:TP ratios, TN:TP ratios, and rates of GPP and ER. However, consumer assemblages were more tightly linked to variation in nutrient availability and production across ponds than to fertilization. Greater declines in benthic diversity occurred in ponds with higher average TN:TP ratios during the experiment. Consistent with predicted effects of cladocerans on nutrient availability, shifts in cladoceran abundances were positively associated with average water column TN:TP ratios during the experiment. Finally, elevated GPP and ER were associated with greater increases in the abundance of benthic invertebrate predators, suggesting the possibility of top-down control. Our study highlights the critical role of consumer-mediated processes in the interaction between nutrient availability and production. Manuscript HighlightsO_LIFertilization reduced pond gross primary production and ecosystem respiration rates. C_LIO_LIInvertebrate predator abundance was inversely related to gross primary production. C_LIO_LIShifts in consumer assemblages were tightly linked to nutrients and production. C_LI

Encounter rate models are important tools for evaluating and estimating trophic interactions between species. While encounter rate parameters have been measured for many freshwater pelagic fishes, most benthic fishes remain mostly unstudied. Those few efforts to generate encounter rate models for benthic fishes often hold mathematical assumptions based on visual foraging, despite the many cases in which benthic fishes employ the lateral line to forage. Furthermore, encounter rate models are rarely compared, despite the many cases in which prey animals face predation risk from multiple types of predators. For example, the macroinvertebrate Mysis is exposed to both benthic and pelagic predation risk during diel vertical migration (DVM). Comparing the risks between habitats could help evaluate predation risk as an ultimate cause of their DVM behavior. We created a novel encounter rate model based on lateral line ("tactile") foraging by sculpins (Cottidae) given the saltatory (stop-and-go) nature of their movement. The tactile model demonstrated variation in behavior and peak encounter rate with detection distance, movement velocity, and rest durations. We then directly compared predation risk for Mysis by parameterizing both our tactile benthic (2D) encounter rate model for sculpin and a visual pelagic (3D) for rainbow smelt (Osmerus mordax). Tactile encounter rates were generally lower than visual rates for individual predators. However, population level encounter rates at night were greater in the benthic habitat than the pelagic habitat. Overall, our model estimates of encounter rates were consistent with the long-standing hypothesis that predation is an ultimate driver of DVM behavior.

O_LIEmpoasca fabae is a migratory pest that overwinters in the Southeastern United States (US) and damages crops throughout its summer range in North America. Its spring arrival has advanced by 9.7 days between 1951 and 2012, and increased damage is linked to warmer conditions that accelerate host and pest development. Yet whether this advance is also associated with a northward expansion of its winter survival area remains an open question. C_LIO_LIHere, we analyzed 126 years of minimum temperature data across the contiguous US to address this question. Using its winter survival threshold (-9{degrees}C), we calculated the annual winter survival area for E. fabae (temperature-only) and tested for time-series trends. We also mapped the potential overwintering area (temperature + winter hosts) under evergreen and pine-only forest scenarios. C_LIO_LIThe estimated winter survival area varies over 126 years, showing a nonlinear pattern. However, we found no significant trend, change-point year, or rate of change. This lack of significance was also observed when considering the 1951-2012 period. C_LIO_LIThe Southeastern US remained consistently suitable for winter survival, while the northern edge varied latitudinally, especially within the range of 35{degrees}-40{degrees}N, with no clear trend. C_LIO_LIPotential overwintering areas extend into Central Florida and the Texas Gulf Coastal Plain but exclude parts of Tennessee. In the pine-only scenario, the area in Mississippi and Alabama would be smaller. C_LIO_LIThe winter survival area for E. fabae has not continually expanded. The Southeastern US area remains suitable for over 126 years, whereas the northern range varies dynamically. C_LI GRAPHICAL ABSTRACT AND HIGHLIGHTS O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=78 SRC="FIGDIR/small/727670v1_ufig1.gif" ALT="Figure 1"> View larger version (22K): org.highwire.dtl.DTLVardef@1062508org.highwire.dtl.DTLVardef@696e4borg.highwire.dtl.DTLVardef@1c7ff29org.highwire.dtl.DTLVardef@14109c5_HPS_FORMAT_FIGEXP M_FIG C_FIG O_LIThe winter survival zone (temperature only) of Empoasca fabae has not expanded continuously over the past 126 years. C_LIO_LIThe Southeastern United States remained suitable over this period, with the maximum northward extent of potential survival reaching 45{degrees}N and high variation within the range of 35{degrees}-40{degrees}N. C_LIO_LIUpdated potential overwintering zones (temperature + winter hosts) extend into Central Florida and the Texas Gulf Coastal Plain. C_LI

O_LISpawning salmon transport marine-derived nutrients (MDN) into riparian forests, influencing soil, plant, and animal communities, yet their effects on fungal communities remain poorly understood. C_LIO_LIWe used DNA metabarcoding to examine fungal responses to three spatial patterns of salmon-derived nitrogen (N) in southwest Alaska: (i) patchy inputs from wildlife-deposited carcasses, (ii) a 21-year carcass relocation experiment, and (iii) natural N gradients with distance from streams. C_LIO_LIDecomposing carcasses increased saprotrophic fungal diversity, identifying taxa responsible for salmon carcass decomposition. Long-term carcass relocation reduced diversity of medium-distance fringe ectomycorrhizal fungi (EMF), whereas recent, patchy carcass inputs increased diversity of both medium-distance fringe and long-distance EMF--guilds often associated with low-nutrient environments. Along natural stream N gradients, EMF responses varied markedly within functional guilds and genera, revealing unexpected variation in N sensitivity among closely related taxa. C_LIO_LIPulsed, spatially heterogeneous nutrient inputs enhanced diversity of typically nitrophobic EMF, likely reflecting their capacity to maintain extensive mycelial networks, exploit nutrient hotspots, and mobilize organic N and phosphorus. The diversity of responses along natural N gradients suggests that mechanisms linking EMF traits to nutrient acquisition and tolerance remain unresolved. Our findings emphasize the importance of linking fungal community composition with functional attributes and nutrient dynamics. C_LI

Understanding how management alters species biodiversity and interactions is critical for sustainable agriculture. This can be especially important for rangelands, grasslands used for livestock grazing that cover 30% of land worldwide. In rangelands, ranchers need to maximize livestock production while supporting healthy ecosystems. Grazing management can alter the impact of livestock by varying grazing timing and intensity, but its ecological impacts remain poorly understood. One critical function that may be supported in these systems is pollination; how rangeland management may alter this ecosystem service is unknown. We investigated how rotational stocking, where livestock are rotated among pastures, affected plant and pollinator communities and plant-pollinator interactions using working ranches in the Southern Great Plains. Sites were managed through continuous stocking or rotation with low or high frequency. We found that high-frequency livestock rotation supported greater flower abundance, and consequently greater pollinator abundance. Pollinator orders varied in their responses to management with Hymenoptera directly responding to management, and Coleoptera and Lepidoptera responding indirectly via changes in flower abundance. Community-level changes produced more specialized interaction networks that likely support more stable communities and higher interaction diversity. These community changes, and resulting species turnover, led to high interaction turnover across rangeland sites. This suggests that a mosaic of management strategies likely diversifies habitat and helps support plant and pollinator biodiversity at the landscape scale. This study demonstrates that rangelands can support plants, pollinators, and their interactions, particularly when managed with high-frequency rotational stocking.

O_LIAgricultural intensification can support the expansion of introduced species which are highly adapted to human-modified landscapes, but the mechanisms by which this occurs are often unclear. C_LIO_LIHere we investigate the spatial ecology of a rapidly expanding introduced bumble bee (Bombus impatiens) and a native congener (B. mixtus) in agricultural landscapes of southwestern British Columbia, Canada. We used microsatellite genotyping and spatially explicit capture-recapture models to compare the foraging distance of the two species, and fitted hierarchical models to compare their abundance, behaviour (nest searching vs foraging), and lineage survival as a function of landscape composition and configuration. C_LIO_LIWe found that B. impatiens had a broader foraging range than B. mixtus, and that its colony/worker abundance were positively associated with the surrounding area of residential gardens, but decreased relative to B. mixtus abundance in response to increasing seminatural area. In contrast, B. mixtus colony abundance decreased in landscapes with a greater area of intensively managed berry crops. C_LIO_LIWe observed fewer B. impatiens queens per survey in landscapes with more low-disturbance landcover, and hypothesize space use of this species could be shaped by concentration on potential nesting habitat. Consistent with this observation, nest searching behaviour was more common for B. impatiens queens, while B. mixtus queens were primarily observed foraging, suggesting these two species derive different value from agricultural landscapes during colony establishment. C_LIO_LIFinally, we found that the rate of lineage re-capture between 2022 colonies and 2023 spring queens was nearly 10-fold higher for B. impatiens than for B. mixtus, indicating a greater capacity of the introduced species to complete its life cycle in agro-natural landscape mosaics. C_LIO_LIOur results suggest that differences in spatial ecology may contribute to the differential success of these two species in human-modified landscapes, and provide insight into the mechanisms by which land-use change shapes community composition. C_LI O_FIG O_LINKSMALLFIG WIDTH=184 HEIGHT=200 SRC="FIGDIR/small/723627v1_ufig1.gif" ALT="Figure 1"> View larger version (62K): org.highwire.dtl.DTLVardef@1e72eacorg.highwire.dtl.DTLVardef@a958a0org.highwire.dtl.DTLVardef@1f970b6org.highwire.dtl.DTLVardef@156f522_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstract. Coloured diagrams of B. mixtus and B. impatiens are credited to Elaine Evans and the Xerces Society, with permission.

Mark-recapture analyses on the delineation of natural populations between areas often assume random sampling, with a between/within (B/W) area resighting ratio that declines towards zero as the population components of two areas become more-and-more isolated from one another, with fewer-and-fewer individuals mixing between areas. I use an individual based population model split in two areas to simulate this result, analysing also for the potential effects of the space-time fidelity of the mark-recapture sampling in the areas. I find that small B/W resighting ratios--that traditionally is taken as evidence of population isolation--can easily be observed within a completely mixing population if a random sampling scheme is restricted in space and/or time. Random sampling within restricted areas and time windows is not sufficient to estimate mixing rates and population isolation between areas, unless the resighting rates are analysed by a method that accounts both for the space-time fidelity of the scientific sampling scheme and the space-time fidelity of the distributional behaviour of the individuals in the population.

Ectomycorrhizal (EcM) fungi are well-recognized symbionts impacting tree health and ecosystem functioning globally, yet understanding of their timing of proliferation in soils across seasons and years remains limited. We analyzed monthly patterns of EcM fungal abundance and community structure over two years in five temperate monodominant forest plots via quantitative PCR and Illumina sequencing. We found that the phenological dynamics of EcM fungi differed significantly by host tree leaf habit, fungal exploration type, fungal genus, and soil moisture. Overall, total EcM fungal abundances based on qPCR consistently peaked in autumn, and were more dynamic in evergreen than deciduous plots, supporting ideas of surplus carbon and asymmetric above-belowground dynamics. Longer-distance exploration types peaked earlier and were more stable than shorter-distance types, suggesting an independent and supportive role in releasing spring nutrients. About half of 20 focal taxa consistently peaked in either autumn, summer, or spring, while others were either host- and/or year-dependent. Our findings highlight that phenology is a key EcM fungal trait best explained by both host and fungal contributions, and future studies across biomes should consider seasonal shifts and sampling to elucidate phenological traits. Summary- The timing of belowground production and seasonal community dynamics remain poorly understood for ectomycorrhizal (EcM) fungi. - We collected soils monthly for two years from five temperate monodominant forest plots. - Fungal production peaked in autumn, shorter-distance and evergreen-associated spanned wider ranges, and half of focal fungal genera showed seasonal preference, emphasizing autumn surplus carbon and spring nutrients from long-distance types. - Future studies should consider seasonal shifts when sampling EcM fungal communities, and forest carbon models should include asymmetric above-belowground phenology. Translated Summary (Spanish)- La fenologia de la produccion y composicion de comunidades de hongos ectomicorrizicos (EcM) es poco estudiada. - Recolectamos suelos mensualmente por dos anos de cinco parcelas mono-dominantes templados. - Produccion maxima de hongos ocurrio en otono, hongos asociados con arboles siempreverdes y de exploracion de corta-distancia observaron rangos mas amplios, y la mitad de generos de hongos focales observaron preferencia estacional, enfatizando extra carbono en otono y nutrientes en primavera de tipos larga-distancia. - Estudios deben considerar cambios estacionales para el muestreo de hongos EcM, y modelos de carbono deben incluir fenologia asimetrica entre hojas y hongos. Plain language summaryEctomycorrhizal fungi are critical for the global carbon cycle, but their seasonal and inter-annual growth patterns remain unclear. We sample soil DNA monthly over two years across five different monodominant temperate forest stands. We find an overall belowground peak in autumn, with significantly later growth under wetter conditions, more dynamism with evergreen trees, and distinct spring growth by longer-distance fungi.

Quagga mussels (Dreissena rostriformis bugensis) are ecosystem engineers that can alter nutrient cycling, benthic-pelagic coupling, and food-web structure in deep lakes. Although their invasion trajectories are well documented in the Laurentian Great Lakes in North America, depth-specific population dynamics remain poorly resolved in recently invaded European perialpine lakes. We analyzed five annual lake-wide surveys (2021-2025) from 54 stations spanning 2.4-253 m depth in Lake Constance to quantify changes in quagga mussel density, biomass, and shell-length distribution. Contrary to expectations of lake-wide exponential growth, shallow-water populations (< 20 m) showed no significant increase during the study period and appear to have reached carrying capacity before monitoring began. In contrast, densities increased monotonically at intermediate depths (40-125 m), indicating ongoing expansion into deeper strata. Mean shell length declined with depth, and size distributions in shallow waters shifted toward larger individuals, consistent with a transition from active recruitment to somatic growth of established mussels. Compared with the Laurentian Great Lakes, Lake Constance already has substantially higher shallow-water biomass, whereas deeper invasion trajectories are broadly similar. These results show that quagga mussel invasion in deep European lakes can combine rapid littoral saturation with slower profundal expansion, complicating direct transfer of predictions from the Great Lakes. Continued depth-stratified monitoring will be essential for anticipating future ecosystem effects in perialpine lakes.

Disturbance is widely recognized as a catalyst of invasion, but growing evidence suggests even protected communities are susceptible to severe infestation. We used k[i]pukas--naturally isolated patches of minimally-disturbed vegetation surrounded by lava flows--as a large-scale natural experiment to test the long-term biotic resistance of protected sagebrush ecosystems threatened by Bromus tectorum and other invasive annual grasses. Employing a robust causal inference approach combining matching with regression adjustment, we compared protected communities within k[i]pukas to otherwise similar communities exposed to contemporary disturbance regimes. Despite their near-total protection from fire and livestock grazing, k[i]pukas were extensively invaded by annual grasses (18.9 {+/-} 0.28% cover), with abundance comparable to or slightly exceeding disturbed sites (16.7 {+/-} 0.29% cover). These findings challenge the notion that protection from disturbance confers effective long-term resistance to invasion, instead demonstrating that invaders can establish, proliferate, and drive ecosystem transformation where favorable abiotic conditions prevail. Our findings reveal the limits of passive protection as a conservation strategy, suggesting active management may be necessary to prevent ecosystem degradation by aggressive invaders.

The Northwest Forest Plan (NWFP) Passive Acoustic Monitoring (PAM) program is a large-scale interagency biodiversity monitoring framework designed to assess the status and trends of northern spotted owls (Strix occidentalis caurina), barred owls (Strix varia), marbled murrelets (Brachyramphus marmoratus), and broader forest biodiversity across federally administered lands in the Pacific Northwest. In 2025, we deployed autonomous recording units at 2,095 sampling stations within 532 5-km2 hexagons randomly selected across approximately 24 million acres of federal forest lands in Washington, Oregon, and California. These deployments generated 1.37 million hours of acoustic recordings that we processed using the convolutional neural network PNW-Cnet v5 for automated species identification and subsequent human validation of focal species detections. Northern spotted owls were detected in 28% of sampled hexagons range-wide, including 16% in Washington, 25% in Oregon, and 60% in California. Occupancy patterns remained consistent compared to previous years, with higher occupancy concentrated in southern portions of the geographic range and continued low occupancy across much of the Washington Cascades and Oregon Coast Range. Barred owls were detected in 86% of sampled hexagons and remained broadly distributed throughout most of the NWFP area. Marbled murrelets were detected in 50% of reviewed hexagons within NWFP marbled murrelet management zones, with highest occupancy occurring in coastal forests of Oregon and Washington. The 2025 field season occurred under substantial operational constraints that reduced sampling effort by approximately half relative to 2023 and 2024 because of staffing limitations affecting participating federal agencies. Despite these reductions, the NWFP-PAM framework continued to provide broad-scale, spatially representative ecological information across the NWFP area. Results highlight the growing importance of passive acoustic monitoring and machine learning approaches for long-term biodiversity monitoring under changing environmental and operational conditions.

Repeated grazing and trampling can reduce forb populations in South African mesic grasslands by limiting photosynthesis and depleting carbohydrate reserves stored in underground organs. We examined the effects of repeated defoliation on growth, bulb starch reserves and water status in the geophyte Eucomis autumnalis over 468 days. Four intense summer and autumn defoliations reduced above-ground production, bulb mass, starch reserves and bulb water pools, with the strongest impacts occurring in late summer and autumn when plants normally replenish reserves. Repeated defoliation disrupted seasonal source sink dynamics, forcing resources into regrowth and driving bulbs towards energetic bankruptcy. These results highlight the importance of avoiding heavy autumn grazing and providing periodic full-year rests to conserve geophytic forbs in mesic grasslands.

Wildlife feeding during the wild turkey (Meleagris gallopavo) hunting season is legal in many states within the United States, but hunting turkeys with the aid of bait is unlawful in most states. The most common policy to prevent wildlife feeding from acting as bait is to restrict hunting within a defined radius. However, the effect of wildlife feeders on turkey harvest risk and the effectiveness of distance restrictions on mitigating that influence have not been investigated. During 2024-2025, we used GPS transmitters to track 30 adult male turkeys during the spring hunting season on private land with active feeders in Florida, USA, where hunting turkeys within a 91 m radius of a feeder was unlawful. We used Cox proportional hazard models to link risk of hunter harvest with unique feeders visited daily, number of feeders within a home range, and average morning distance and roosting distance to feeders at multiple temporal scales. Hunters harvested 53% of the tagged turkeys. Risk of hunter harvest increased with the number of unique feeders visited the previous day and after the first three days of hunting season with the number of active feeders within a home range. As distance from the most recent roost site and average morning distance to a feeder decreased, risk of hunter harvest increased. We estimated that risk of hunter harvest would be reduced by over 50% if distance restrictions were increased from 100 m to 200 m, by nearly 75% with an increase from 100 m to 300 m, and by nearly 90% with an increase from 100 m to 500 m. To completely eliminate the influence of wildlife feeders on risk of hunter harvest would require a restriction distance well beyond a 500m radius, which is impractical given that this radius would result in an area twice the average private landowner property size in the region. Thus, if wildlife feeding during the turkey hunting season is to be allowed, it will act as bait, in which case, the acceptable level of its influence as bait can be achieved with the appropriate hunting radius restriction.