Breeding phenological responses to changing environments affect demographics and population persistence. However, inter-individual variation in adjustment of reproductive timing to predation risk has been overlooked. We thus tested whether increasing natural predation risk enhanced or homogenized reproductive timing of females differing in risk sensitivity. Using behavioral (flight initiation distance, FID) and cognitive (relative head volume) proxies of risk sensitivity, we analyzed laying dates of female common eiders (Somateria mollissima) breeding in SW Finland (Baltic Sea) relative to conspecifics under fluctuating predation pressure, while accounting for breeding experience and body condition. We found that high predation risk was associated with a divergence of female eider breeding phenologies depending on cognitive but not behavioral proxies of risk sensitivity. Accordingly, relatively large-headed females, assumed to be more risk-sensitive, bred later than small-headed ones following years of high adult or nest predation risk-plausibly reflecting extended nest prospecting in risk-sensitive individuals-leading to greater laying asynchrony. In contrast, females displaying longer FIDs (more risk-sensitive) bred earlier than those displaying shorter FIDs, but this response was irrespective of the level of predation risk. Because FID was measured late in incubation, we hypothesize that it may more strongly reflect state-dependent parental investment in the current breeding attempt than risk sensitivity during nest initiation, with higher parental investment promoting delayed escape. Additionally, experienced breeders bred earlier than inexperienced ones. More attention should be given to cognitive traits and behaviors associated with risk sensitivity to better understand variation in individual breeding phenology and synchrony.

Effective conservation of the iconic old forest lichen Lobaria pulmonaria depends on understanding its life history bottlenecks. To address this, reproductive dynamics were evaluated in 302 juvenile and early-reproducing thalli transplanted across environmental gradients-including elevation, canopy openness, and bark pH-in pristine British Columbian forests over a 14months period. Soralia cover increased significantly but at a slow rate, with marginal soralia appearing earlier and more frequently than laminal soralia. The intrinsic trait of initial total soralia cover emerged as the strongest predictor of the change in reproductive effort. Additionally, thalli with low specific thallus mass at start (STMStart) and rapid growth rates exhibited reduced reproductive activity. Environmental stressors, such as high-light-induced chlorophyll bleaching and elevated altitude, weakly inhibited soralia development. Sexual reproduction was rare, with apothecia present in only 2% of transplants and no new apothecia forming during the study. The findings highlight the slow pace of soralia formation and, coupled with the species' long generation time, suggest that current forest rotation cycles in managed forests may be insufficient to sustain viable L. pulmonaria populations. Conservation strategies should therefore account for both slow reproductive onset and sensitivity to environmental conditions.

Understanding the impact of plant invasion on multitrophic community dynamics and coexistence requires widespread and frequent monitoring. Deep learning can be used to automate the measurement of indicators of ecological interactions and ecosystem functioning. In this study, we used a consumer-grade drone paired with deep learning to assess floral density in meadows invaded by the dog-strangling vine Vincetoxicum rossicum (Kleopow) Barbar. (Gentianales: Apocynaceae) at the Rouge National Urban Park in the Greater Toronto Area, Ontario, Canada. Alongside these measurements, observations of pollination and herbivory was completed on Symphyotrichum novae-angliae (L.) G.L.Nesom (Asterales: Asteraceae), a self-incompatible, pollinator-dependent native plant that experiences herbivory by a widespread specialist weevil, Anthonomusrufipes LeConte (Coleoptera: Curculionidae). Our results suggest that as invasion progresses, pollination services are reduced due to the decrease in floral density which suppresses pollinator abundance and activity. Conversely, while herbivory had a strong effect on plant reproduction, it was density independent and thus unaffected by direct effects of invasion, but rather indirect through reduced host abundance. By pairing deep learning with drone technology, we detected patterns consistent with a reduction of pollinator habitat quality along the invasion gradient. Furthermore, we find that invasion appears to suppress plant reproduction by means of separate processes that are either independent of or dependent on pollination. Overall, the results suggest that invasion reduces pollinator habitat quality while simultaneously resulting in ecological conditions consistent with the reproductive impairment of late-season flowering resident plant species.

The plateau pika, a keystone species of the Tibetan Plateau, is also widely poisoned as an agricultural pest. An intriguing observation is that pika are more abundant where their main competitor (domestic yak) is also most abundant. A recent study showed that this may be because pika supplement their diet in winter by consuming yak feces. Here we used quantitative fatty acid signatures analysis to explore pika diet and detect the possibility of coprophagy. We collected fat tissue from pika at 3 sites of varying elevation, and compared the abundance of 10 fatty acids (FA) in their body fat with those in their main potential foods (grass, roots and feces). We used an optimization program to establish the best-fit diet to the observed FA distributions, using mouse fat as a negative control. Pika fat FA signatures matched plateau foods far better than mouse fat. Faeces consumption doubled as the elevation of the site increased from 12.8% at the lowest site to 26.8% at the highest. In contrast consumption of roots showed the opposite pattern, comprising 32% at the lowest elevation and falling to virtually zero at the highest. That might reflect the time that the surface ground is frozen inhibiting the ability to dig for roots at higher elevation sites. Our data support the previous suggestion that pika eat yak feces, potentially giving them an over-winter survival advantage increasing their populations where yak are abundant. The full extent of coprophagy however requires more data in a larger population sample.

Fertilization and herbivore exclusion are two key forces influencing community structure and species richness in grassland ecosystems. However, the extent to which these factors influence the relative contributions of deterministic and stochastic processes in community assembly remains poorly understood. In this study, we conducted a five-year field experiment that manipulated nutrient availability and herbivore exclusion in an alpine meadow on the eastern Qinghai-Tibet Plateau. The results showed that fertilization, herbivore exclusion, and their combination significantly decreased species richness and drove Raup-Crick dissimilarity close to - 1 relative to the control. In the final year of the experiment, these treatments drove a distinct directional shift in community composition, diverging significantly from the control. Furthermore, all treatments significantly increased community-weighted mean (CWM) height and specific leaf area (SLA), and these shifts in fast resource-acquisition traits were significantly correlated with the intensification of deterministic processes (i.e., Raup-Crick dissimilarity approaching - 1). Consequently, we conclude that in natural alpine meadows (control), community assembly is primarily driven by stochastic processes. In contrast, the experimental treatments diminished the influence of stochasticity, establishing the dominance of deterministic processes through environmental filtering. This shift in assembly patterns was largely mediated by plant functional traits. Because this filtering strongly selected for dominant species possessing fast resource-acquisition traits and exceptional competitive abilities for light, it ultimately led to community homogenization and a decline in species richness. Notably, the combined treatment did not yield a stronger deterministic effect than either treatment alone, indicating a lack of an additive effect.

Foliar endophytic fungi (FEF) influence plant performance and early litter decay, yet whether leaf senescence imposes common assembly rules across hosts remains unclear. Here, we collected paired live and senescent leaves from 11 plant species across three spatial blocks (66 FEF samples) in an alpine meadow on the Tibetan Plateau and characterized FEF communities and leaf functional traits. Our results showed that leaf status, host species, and their interaction structured FEF community composition. Compared with live leaves, senescent leaves harbored higher α-diversity, exhibited lower among-host β-dispersion, and had more core taxa shared across hosts. Senescent leaves showed reduced relative abundance of symbiotrophic modes and increased relative abundance of saprotrophic modes compared to live leaves. At the community level, senescent leaves showed depleted nitrogen and hemicellulose but enriched cellulose and lignin, redirecting trait-community linkages from soluble resources to recalcitrant polymers. The findings highlight that leaf status is a primary driver of endophytic fungal community assembly, and reveal adaptive shifts in endophytic fungal communities associated with leaf senescence.

Population density often modifies the phenotypes of the members of the population. Such density-dependent phenotypic plasticity can affect basic life history traits of the organisms. In insects, a frequently observed expression of such plasticity is the crowding response (CR), where individuals growing at high densities develop faster and attain lower final sizes compared to those at low densities. This plastic change qualitatively differs from the general stress response where lower final sizes are associated with longer development periods. The adaptive significance of CR, as well as the nature of the cues that trigger CR, remains poorly understood. We performed a series of experiments to identify proximate signals leading to CR in the geometrid moth Hypomecis atomaria, a species in which larvae reared in groups consistently pupate earlier and at lower weights than those reared in isolation. Our findings reveal that CR is also induced in complete darkness, suggesting that visual cues of high population densities do not play a decisive role. CR was triggered when the larvae were separated by a mesh barrier, preventing tactile interaction between them. The presence of heterospecific lepidopteran larvae also triggered CR, though to varying degrees. By contrast, neither the presence of dipteran insects in the rearing environment nor human-inflicted tactile stimulation affected the growth schedules of H. atomaria larvae. We conclude that CR is likely induced either by chemical signals or substrate-borne vibrations caused by other larvae. In any case, CR is not a highly specific response to high densities of conspecifics, nor is it a very general reaction to unspecific disturbances. This allows us to narrow down the set of potential adaptive explanations for the phenomenon.

Elevational replacement distribution patterns underpin montane diversity and reflect the interaction of both biotic and abiotic pressures, but the degree to which parasites exhibit elevational zonation remains unclear. Investigating infection patterns in related host species across elevational gradients can reveal whether parasites and hosts show concordant patterns of elevational turnover, potentially due to shared historical and ecological factors. Here, we assessed patterns of elevational replacement in haemosporidian parasite assemblages that infect three congeneric songbird species: Bell's vireo (Vireo bellii), gray vireo (V. vicinior), and plumbeous vireo (V. plumbeus), each of which breeds across distinct elevations and habitats in the southwestern United States. We screened a total of 248 individuals using cytochrome b PCR and microscopy. We identified 19 haemosporidian haplotypes, including eight novel lineages. We found that each of the three vireo species exhibited high haemosporidian prevalence (55.0-86.2%), with nearly all infections from the genus Haemoproteus (subgenus Parahaemoproteus). Haemosporidian assemblages varied across elevations; each sampled range of elevations harbored abundant, yet host-specific lineages with different environmental associations. Bell's and plumbeous vireos, but not gray vireos, hosted several phylogenetically distinct, putative generalist lineages, likely reflecting spillover from more diverse local breeding bird communities. Repeated infections in individuals across breeding seasons, together with moderate parasitemia (x̄ ≈ 1%) suggest that these focal vireo species harbor chronic infections during their respective breeding seasons. These results demonstrate that elevational replacement patterns in avian hosts may be mirrored by their haemosporidian parasites, particularly among host-specialized lineages.

The severity of fitness costs resulting from behavioural trade-offs between heat dissipation and activities such as foraging is increasing with advancing climate change. In terrestrial habitats, shade and water may buffer individuals from the negative effects of heat exposure, as may load-lightening in group-living species. We tested the hypothesis that thermal and hygric properties of home ranges (shade and water availability) and social factors (group size) influence the costs associated with hot weather, using a population of white-browed sparrow-weavers (Plocepasser mahali) in the southern Kalahari Desert. Across all sparrow-weaver groups, heat avoidance (shade-seeking) and dissipation (panting) behaviours increased with increasing air temperature (Tair), whereas foraging declined. Birds occupying shadier home ranges delayed the onset of panting to higher Tair and foraged less while maintaining overall peck rates. Birds with access to water foraged more, maintained higher peck rates and sought shade at higher Tair compared to birds without. However, they did not pant more, making the mechanism underpinning their increased foraging effort unclear. Birds in larger groups both panted more overall and sought shade at lower Tair than birds in smaller groups but maintained similar overall peck rates. Taken together, these results suggest birds in shadier home ranges can forage more efficiently, buffering foraging costs at high Tair. Our data therefore suggest that some impacts of increasing Tair under climate change can be buffered by shade availability, but the impacts of water availability and social factors are less clear.

Understanding the multi-scale effects of habitat fragmentation on biodiversity is essential for effective conservation in a rapidly changing world. Here, we assessed plant functional composition in edge and interior plots across 28 islands in Thousand Island Lake, China. Plants were categorized into four functional groups based on life form and shade tolerance. Functional composition was defined as the proportions of functional groups in each plot, island, and virtual landscape. Differences between edge and interior plots were analyzed using the Wilcoxon test, and correlations with island area were evaluated using Spearman rank correlation. The relationship between functional composition and total habitat amounts in virtual landscapes was investigated using SLOSS analysis. We found that interior plots had higher proportions of shade-tolerant trees and lower proportions of shade-intolerant trees, regardless of whether richness- or abundance-based metrics were used. The functional composition of shrubs showed minimal variation with plot type, though edge plots had a higher proportion of shade-tolerant shrubs. Island area affected functional composition differently at the island scale, depending on whether richness-based or abundance-based metrics were used. The relationship between total habitat amounts and functional composition exhibited threshold patterns with unstable and stable phases at the landscape scale. Our study reveals a hierarchical structure in the multi-scale impacts of habitat fragmentation on plant functional composition and highlights different responses of functional groups across scales. Thus, we conclude that fragmentation research must consider ecological impacts at multiple scales and from multiple perspectives.