Ecology and Evolution最新文献

Reduced-representation sequencing methods, such as Restriction-site Associated DNA sequencing (RAD-seq), use restriction enzymes to achieve a cost-effective approach for generating genome-wide SNP data. However, a major limitation of these methods is their inability to directly assay specific loci of interest unless located near restriction sites. Here, we present ampliRAD, a novel method combining targeted (i.e., amplicon) and reduced-representation sequencing. AmpliRAD uses an initial multiplex PCR step to amplify target loci and append restriction enzyme recognition sites onto them. The PCR product is then combined with genomic DNA and used as input for a traditional RAD library preparation protocol, enabling the incorporation of virtually any target loci into a standard RAD dataset. We also introduce updates to an existing RAD protocol, including enzymatic shearing, that enhance its accessibility and efficiency. To demonstrate ampliRAD's utility, we investigate genetic associations with adult migration timing in Dean River Chinook salmon, revealing a clear link between the GREB1L locus and migration timing that extends previous findings from southern populations to this northern river. AmpliRAD provides a powerful new tool for genomic analyses, offering the combined benefits of both reduced representation and targeted sequencing approaches.

Throughout the world, climate change is having many adverse impacts, ranging from the decline of biodiversity to the economic downturn. Increasing temperature will continue to affect microorganisms and ecosystems in a very wide range. In order to mitigate the severity of this irreversible process, it would be helpful to analyze the anticipated scenarios for the coming years. For this purpose, the invasive alien species Trachemys scripta and the native species Emys orbicularis, Mauremys caspica and Mauremys rivulata in Türkiye were projected with five different climate models (ACCESS-CM2, BCC-CSM2-MR, CNRM-ESM2-1, GISS-E2-1-G, and MIROC6) for the years 2050, 2070, and 2090. Suitable habitat areas, habitat expansions, and habitat contractions of species with climate change were modeled. Based on the results of these models, it appears that habitat expansions in the future will probably result in an increase in competition between native and invasive species. Due to habitat contraction in the west, the T. scripta species is expected to migrate toward the coast, which may lead to population declines for E. orbicularis and M. rivulata, especially along the Mediterranean coast. Furthermore, M. caspica, which is distributed in the east, is likely to move toward the western and southern regions due to climate change, where it could compete for habitat with T. scripta as it experiences habitat contraction in the north. This suggests that climate change and the impact of invasive species will lead to habitat loss for native species in the future. Considering this data, it is recommended to increase collection and monitoring efforts in coastal areas where the T. scripta species is currently densely distributed in order to mitigate the occurrence of this predicted scenario in the future.

Many parasites change the behavior of their host. Parasitoid wasps, for example, frequently engage in body guard manipulation to induce behaviors in their hosts that enhance parasite survival after pupation. Parasitoids of aphids have repeatedly been found to alter host location on the plant, thereby influencing the location where their host mummifies, that is their pupation site. Potential benefits of this behavior for the parasite, however, remain under debate. Combining experiments in the laboratory and the field, we tested whether the parasitoid Aphelinus chaonia induces behavioral changes in its aphid host to influence its mummification location and whether these reduce hyperparasitism, an important source of mortality to the developing parasitoid. Aphelinus chaonia clearly caused aphids to move either off the plant or into the leaf axil prior to mummification and host death. However, movement to the leaf axil did not result in any reduction of hyperparasitism. Nevertheless, in the field, mummies situated on the stem were less likely to survive than those elsewhere on the plant, including in the leaf axil. We discuss our findings in the light of potential host manipulation.

Movement is a fundamental process in structuring communities, distributing species, and mediating gene flow. Both extrinsic (e.g., density of species) and intrinsic factors (e.g., body size) influence movement patterns, ultimately driving the spatial organization of ecological communities. However, these extrinsic and intrinsic factors are often assessed in isolation, limiting our ability to understand how multiple factors combine to shape movement patterns in nature. Here, we evaluate whether body size (intrinsic) and intra- and interspecific densities (extrinsic) have an impact on the movement rates of four fish species (Nocomis leptocephalus bluehead chub, Semotilus atromaculatus creek chub, Lepomis cyanellus green sunfish, and L. auritus redbreast sunfish) in a small stream. We employed a capture-mark-recapture framework to individually track movements, defined as the difference between locations on consecutive (re)captures. We then applied a dispersal-observation model that accounts for detectability, survival, and emigration when inferring movement processes. We found that larger individuals of creek chub and green sunfish were more likely to move, which may be explained by their greater physical ability to balance the energetic cost of moving in tandem with greater competitive ability during settlement. The effect of density on movement was mixed. Green sunfish moved away from areas with high density of creek chub, but movement declined when bluehead chub density was high. Bluehead chub responded reciprocally to green sunfish, with less movement at high green sunfish density. Movement also declined for creek chubs in the presence of bluehead chub. This may suggest that certain species interact due to predator-prey interactions either directly or indirectly. Collectively, our results suggest that intrinsic (body size) and extrinsic factors (density) influence movement patterns, but their relative importance is species-specific. Further exploring the mechanistic relationship behind drivers of movement will provide greater insights into spatial community dynamics.

The resources needed by different species are fundamental for allowing multiple species to coexist. However, when species share resources, competition is expected to occur with associated costs. Sociable weavers (Philetairus socius) build large communal nests that provide, among other resources, nesting chambers that provide shelter, protection, thermal buffering and insulation for roosting birds of other species. We consider the interactions of heterospecifics roosting in colonies to determine if species select chambers due to their insulation properties, if there is a dominance hierarchy in acquiring chambers, and/or if novel behaviours to access chambers are employed. Our study demonstrates that different species use different aspects of the nest resource, preferring roosting chambers depending on the location of the chamber within the colony. To access this resource, we show that aggressive interactions occur between the species, resulting in a dominance hierarchy with size being positively related to the dominance of a species. Furthermore, our data show temporal separation in timing of arrival at the chambers, with smaller species tending to arrive later and occupy vacant chambers, thus avoiding aggressive interactions with more dominant heterospecifics. Therefore, adapting to competition, multiple species use novel behaviours and interactions, allowing them to coexist at this same engineered resource.

Sexual dimorphism in lizards arises from the dynamic interplay between natural and sexual selection, manifesting in divergent phenotypic traits across taxa. A key unresolved question is whether the relationship between such sexually dimorphic traits and functional performance also differs between the sexes. This study investigated this question in the mountain dragon (Diploderma vela), a protected species endemic to the upper Lancang River basin in southwestern China, by quantifying its sexual dimorphism in morphology and coloration and assessing their sex-specific correlations with bite force. A total of 94 individuals were assessed for nine morphological traits, maximum bite force capacity, and body coloration across 15 anatomical regions. After controlling for body size, significant male-biased dimorphism was detected in most morphological traits, whereas abdomen length was female-biased. Coloration also differed between sexes across all measured regions except the abdomen. Crucially, the relationship between morphology and bite force was sex-specific; different suites of traits predicted bite force in males versus females. In contrast, no correlation was found between coloration and bite force in either sex. These divergences reflect the species' flexible phenotypic responses to varying reproductive and ecological pressures. These findings demonstrate that sexual dimorphism extends beyond trait means to encompass sex-specific phenotype-performance relationships, highlighting differential adaptive responses. This work provides a functional framework for understanding trait evolution in D. vela and underscores the need for sex-specific considerations in its conservation.

Urbanization is irreversibly transforming natural ecosystems globally, yet we still lack a holistic understanding of the challenges and opportunities that urban environments present to wildlife. To investigate how raptors utilize urban landscapes, we analyzed 4 years of GPS tracking data of 22 juveniles collected during natal dispersal, combined with 7 years of nest-monitoring data from an urban population of the Common Buzzard (Buteo buteo), an opportunistic rodent specialist, in Berlin (Germany). Our goals were threefold: (a) to estimate core foraging ranges (CFRs), (b) to characterize small-scale temporal foraging areas (TFAs) within these ranges, and (c) to model the breeding habitat suitability based on environmental predictors. CFRs were distributed across the city, with a mean area of 11.0 km² (±13.9 sd). TFAs within these ranges had a mean area of 0.2 km² (±0.3) and were occupied over a mean time span of 274 days (±198). TFAs were mostly located in residential open areas (e.g., courtyards) and were characterized by decreasing area and shorter occupation duration with increasing human population density. Urban TFAs showed a high prevalence of rats (Rattus norvegicus). Active pest control measures were observed at most TFAs, particularly in residential areas. We mapped a total of 17.3 km² of suitable breeding habitat within the study area (217 km²) and 45.4 km² when projected across the city region (890 km²). Suitable breeding habitat consisted of isolated patches, i.e., single courtyards in residential areas, and a network of urban green spaces, e.g., city parks and cemeteries. Cities can provide profitable foraging and breeding conditions for raptors, with abundant prey in proximity to suitable breeding sites. The study improves our understanding of how raptors utilize the urban city landscape and underlines the importance of urban green spaces as a basis for the protection and conservation of urban wildlife.

Local fish diversity in lakes has severely declined in the last century under the effects of climate change and human activities. Thus, examining the underlying factors and implementing appropriate measures are crucial for preventing further aquatic biodiversity losses. Environmental DNA (eDNA) metabarcoding represents a promising tool for improving fish population monitoring. While spatiotemporal variations of fish eDNA in lentic ecosystems have become a research focus, effective monitoring techniques remain limited. Therefore, this study used eDNA metabarcoding to monitor the diversity and spatiotemporal distribution of fish in Erhai Lake, China. Water samples from the shore, nearshore, and midline were collected from 2020 to 2021 during summer and autumn. Thirty-six taxa, including 5 native (one endangered species, Schizothorax taliensis) and 31 non-native taxa, were detected. Seasonal and spatial differences in fish community structure were observed. The seasonal distribution was primarily influenced by water temperature and nutrient status, while the spatial distribution was affected by water depth. Most fish species found in the lake were detected in shoreline samples, suggesting that shoreline sampling is a cost-effective strategy for monitoring fish diversity. These findings confirmed that fine-scale spatial sampling and eDNA metabarcoding represent effective tools for monitoring fish diversity and spatiotemporal distribution in lakes.

Climate change-induced grassland degradation has exacerbated the spread of toxic plants, yet many potentially toxic species remain overlooked, undermining rangeland management and causing significant economic losses. Quantifying the toxicity and distribution of potential toxic plants under climate change is critical for mitigating biogeographic risks. As a case study, taking Sphaerophysa salsula, a leguminous plant distributed in Asia and the Americas, historically utilized for erosion control but recently associated with livestock poisoning, this research integrated toxicity identification, species distribution modeling (SDM), and risk assessment to evaluate its biogeographic threats in China. Results suggested for the first time that S. salsula can function as a high-toxicity (chemotype 1) locoweed due to swainsonine (mean content 0.373%), produced by its endophyte Alternaria oxytropis (23.46 pg/ng), which is implicated in locoism-like syndromes in livestock. The Maximum Entropy model identified temperature annual range (43.22°C), mean temperature of the driest quarter (−6.29°C), and soil pH (8.61) as key distribution drivers. Currently, suitable habitats are concentrated in Northern China (Xinjiang, Inner Mongolia, Ningxia). By the 2070s, these habitats are projected to decline by 6.3%–9%, shifting westward toward pastoral regions. Risk assessments integrating grazing intensity revealed high-risk zones in Gansu, Ningxia, and Inner Mongolia, with future scenarios predicting declining risks in eastern Inner Mongolia but increasing threats in western Tibet. These findings clarify S. salsula's toxic mechanism and biogeographic risks, providing a framework for targeted management of overlooked toxic plants under climate change.

The endemic Sri Lankan leopard is the island's apex predator, living both within and outside protected areas. In unprotected, shared landscapes, it is important to understand leopard diet and predation patterns to foster long-term human-leopard coexistence. This study examines the diet of leopards in the human-dominated tea estate landscape of the Upper Kelani River Basin, in Sri Lanka's Central Highlands. Study goals were to evaluate prey composition, diversity, importance and selection, and to investigate the role of domestic species in leopard diet here. Analysis of 107 leopard scat samples showed leopard feeding behavior was best characterized as generalist and opportunistic, with a wide-ranging diet (H' = 2.89) consisting of 17 evenly consumed (D = 0.94) prey species. While the diminutive black-naped hare (2.5 kg) was most available and most frequently detected in the diet (19.8% of samples), the importance of medium-sized prey was highlighted, with barking deer (25.5 kg) well utilized (13.9% of samples), representing > 20% of total biomass consumed and showing positive selection (0.281). Moderate selectivity was observed for sambar (0.410), the system's largest potential prey (160-215 kg), which may be expected for meso-carnivores in the absence of dominant intraguild competition. Primates are a key resource here (23% of samples and biomass) despite being uncommon in tea estates, suggesting preference by leopards. Targeted research to quantify primate abundance and selection is recommended. Overall, wild species represented > 85% of leopard diet, suggesting the landscape retains a substantial natural prey base. Domestic dogs, though common and widely perceived as targeted by leopards here, were moderately avoided (-0.378), a positive outcome for human-leopard coexistence. These findings highlight the leopards' generalist predation tendencies, while suggesting additional complexity and signaling selectivity in predation patterns. Results underscore the necessity of preserving wild prey abundance and diversity to facilitate coexistence in anthropogenically transformed environments.