Ecology and Evolution最新文献

During an intensive study of the urban population of the blackbird Turdus merula in Szczecin (1997–2023), four cases of surrogate copulation were observed in the blackbird and three in the fieldfare Turdus pilaris. In three cases, birds (blackbirds twice and fieldfare once) try to copulate with fledglings of their own species, and in all other cases, the birds try to copulate with moss and sticks. In three cases copulation, attempts were done by adult birds (two blackbirds and one fieldfare), and in four cases, it was a fledgling.

Interspecific interactions are important drivers of population dynamics and species distribution. These relationships can increase niche partitioning between sympatric species, which can differentiate space and time use or modify their feeding strategies. Roe deer Capreolus capreolus and red deer Cervus elaphus are two of the most widespread ungulate species in Europe and show spatial and dietary overlap. However, limited information is available on their interspecific relationships, especially in mountainous areas. In this study we used 5 years of camera trapping data collected in the Stelvio National Park (Central Italian Alps) to investigate spatial and temporal interactions between roe deer and red deer. Analyses were based on 2060 and 9030 roe deer and red deer detections, respectively, collected from July to September, from 2019 to 2023, using 50 camera traps randomly distributed over a 10,000-ha study area. Spatial interactions were assessed by fitting a single-season, single-species occupancy model to calculate the probability of roe deer detection and occupancy as a function of relative red deer abundance and site-specific environmental covariates. Temporal interactions were obtained by comparing the diel activity patterns of the two species. Results showed no significant effect of red deer relative abundance on the probability of presence of roe deer. Spatial analysis suggested a higher probability of roe deer presence in forested habitats, at lower elevations, and in areas with gentler slopes. Diel activity patterns of roe deer were consistent across sites with higher and lower red deer relative abundance, with moderate to high interspecific overlap, suggesting moderate temporal partitioning and no major support for temporal avoidance of the latter by the former. The high degree of overlap between the two species may be the result of area-specific ecological conditions, such as the widespread distribution of red deer during the summer period, as well as of the adoption of strategies that favor coexistence.

Over lifetime, organisms can be repeatedly exposed to stress, shaping their phenotype. At certain, so-called sensitive phases, individuals might be more receptive to such stress, for example, nutritional stress. However, little is known about how plastic responses differ between individuals experiencing nutritional stress early versus later in life or repeatedly, particularly in species with distinct ontogenetic niches. Moreover, there may be sex-specific differences due to distinct physiology. Larvae of the holometabolous turnip sawfly, Athalia rosae, consume leaves and flowers, while the adults take up nectar. We examined the effects of starvation experienced at different life stages on life-history, adult behavioural and metabolic traits to determine which stage may be more sensitive and how specific these traits respond. We exposed individuals to four nutritional regimes, either no, larval, adult starvation or starvation periods as larvae and adults. Larvae exposed to starvation had a prolonged development, and starved females reached a lower initial adult body mass than non-starved individuals. Males did not differ in initial adult body mass regardless of larval starvation, suggesting the ability to conform well to poor nutritional conditions. Adult behavioural activity was not significantly impacted by larval or adult starvation. Individuals starved as larvae had similar carbohydrate and lipid (i.e., fatty acid) contents as non-starved individuals, potentially due to building up energy reserves during development, while starvation during adulthood or at both stages led to reduced energy reserves in males. This study indicates that the sensitivity of a life stage to stress depends on the specific trait under consideration. Life-history traits were mainly affected by larval stress, while activity appeared to be more robust and metabolism mostly impacted by the adult conditions. Individuals differed in their ability to conform to the given environment, with the responses being life stage- and sex-specific.

The spatial distribution pattern of plant species is frequently driven by a combination of biotic and abiotic factors that jointly influence the arrival, establishment, and reproduction of plants. Comparing the spatial distribution of a target plant species in different populations represents a robust approach to identify the underlying mechanisms. We mapped all reproductive individuals of the Iberian pear (Pyrus bourgaeana) in five plots (1.39–8.57 km²) differing in the activity of seed dispersers and vertebrate herbivores in southern Iberian Peninsula. We used Thomas point process models to quantify the consistency in the spatial pattern and the level of spatial aggregation of this mammal-dispersed tree among the five populations. We tested two hypotheses: (i) because the clumped defecation behavior of some dispersers can lead to local tree aggregation, and because denser groups of fruiting trees can limit seed dispersal by attracting frugivores to specific sites, we expected a consistent small-scale aggregation pattern across all populations; and (ii) because ungulates reduce recruitment by preying on seeds and seedlings, we hypothesize that ungulate activity will show negative relationships with tree density and level of aggregation. Our spatial analysis revealed consistent and highly aggregated small-scale patterns of all Iberian pear populations, with one critical scale aggregation, a low density of clusters and high variability in the number of trees per cluster. Ungulate activity and the number of trees per cluster showed a marginally significant negative correlation, suggesting that in areas with higher ungulate activity, trees tend to form less dense clusters. Although several of the underlying processes varied greatly among the five study sites, the Iberian pear showed a relatively consistent spatial pattern with just quantitative nuances throughout the entire region. This result has significant implications for the reproductive success of the species, management strategies, and ultimately the long-term persistence of populations.

Karst caves are a unique environment significantly different from the external environment; adaptation of cave-dwelling animals to the cave environment is often accompanied by shifts in the sensory systems. Aquatic and terrestrial leeches have been found in the karst caves. In this study, we conducted a transcriptome analysis on the cave-dwelling leech Sinospelaeobdella wulingensis. A total of 29,286 unigenes were obtained by assembling the clean reads, and only 395 genes are differentially expressed in winter and summer samples. Two piezo-type mechanosensitive ion channels (Piezos), eight transient receptor potential channels (TRPs), and six ionotropic glutamate receptors (iGluRs) were identified in the transcriptome. These channels/receptors are transmembrane proteins sharing conserved structural features in the respective protein families. SwPiezo1 shares high identity with Piezos in non-caving leeches. SwiGluRs are conserved in protein sequence and share high identities with homologous proteins in other leeches. In contrast, SwTRPs belong to different subfamilies and share diverse identities with TRPs in other species. Gene expression analysis showed that two SwPiezos, five SwTRPs, and one SwiGluR are abundantly expressed in both winter and summer samples. These results suggest that SwPiezos, SwTRPs, and SwiGluRs are candidate sensory channels/receptors that may have roles in mechanosensory and chemosensory systems. High expression levels of Piezo and TRP genes imply a mechanosensory adaptation of S. wulingensis to the hanging living style in caves. Furthermore, enrichment of sensory genes in the oral sucker indicates the important role of this tissue in response to environmental stimuli. Similar gene expression profiles in winter and summer samples imply a stable physiological status of S. wulingensis in the cave environment.

Estimating the impacts of anthropogenic activities and climate change on species' spatial distributions is crucial for conservation. In this study, based on 62 valid occurrence records of Sphenomorphus incognitus and 24 environmental factors (19 climate factors, 4 topographic factors, and 1 human activity factor), we utilized the biomod2 combined model platform to predict suitable habitats for S. incognitus under two current scenarios (Scenario 1: natural state; Scenario 2: human interference state) and two future climate scenarios (SSP1-2.6 and SSP5-8.5) in 2050s and 2090s. The mean true skill statistic (TSS) and the area under the receiver operating characteristic curve (AUC) suggested that the ensemble model yield more precise predictions than those of individual models. Rainfall and slope were identified as the most important factors influencing S. incognitus distribution. Human disturbance has significantly reduced suitable habitat by 44.13 × 10⁴ km², which is a decrease in 23.95% compared to natural conditions. Spatial analysis revealed substantial fragmentation of suitable habitat due to human activities. The incorporation of anthropogenic factors into the analysis of future climate scenarios has revealed that the area of suitable habitat exhibits divergent trends. Two distinct scenarios have been identified, each of which results in a reduction in the area of the region by 29.58 × 10⁴ km² and an increase by 27.04 × 10⁴ km², respectively, by the year 2090. The primary influence persists in human activities. The centroid of suitable habitat shifted toward the southeast under SSP1-2.6 and toward the northwest under SSP5-8.5. Our findings highlight the significant impact of anthropogenic factors on S. incognitus habitat and emphasize the need for conservation measures. Future research should incorporate additional socioeconomic data to further investigate the effects of human disturbance on this species.

Stream periphyton is an ideal study system for explaining how dispersal shapes community patterns. Few studies have tried to investigate periphyton metacommunities at the reach scale, and studies comparing local versus upstream periphyton propagule sources are lacking. We aimed to address these knowledge gaps by disentangling environmental constraints and dispersal sources, including dispersal hypotheses related to periphyton functional guilds. We covered 25-m sections of streambed with plastic silage cover sheets in three streams in Southern New Zealand, allowing river water to flow over the sheets. Samples on top of these sheets allowed periphyton colonisation only by drifting upstream propagules, while ‘control’ samples placed directly upstream of the plastic sheets were colonised by local and upstream propagules. We collected samples after 7, 14, and 25 days of colonisation. Response variables included periphyton biomass, community structure, and relative abundances of functional guilds. Control samples showed 1.5–6 times higher cell densities than plastic-cover samples, suggesting that local colonisation is very important for biomass accrual. Periphyton communities on both tile types became more similar to each other with time, indicating that environmental filters overcame effects of colonisation sources. While motile and flagellated taxa showed the ability to reach their preferred microhabitats in all streams, the responses of the remaining functional guilds did not follow the expected patterns. We conclude that periphyton community assembly strongly depends on reach-scale connectivity, which results in higher biomass accrual and community structure. These findings suggest that the mass effect paradigm is likely to be the principal metacommunity process shaping stream periphyton communities at the reach scale.

Hibernation is a crucial aspect of the life history of freshwater turtles inhabiting temperate regions. Therefore, understanding their hibernation habitat selection is essential for the targeted conservation of turtle species and their habitats. The Chinese softshell turtle (Pelodiscus sinensis), a medium-sized freshwater turtle, is widely distributed in China; however, populations are rapidly declining, and threatened by habitat destruction, overfishing, and water pollution. Little is known regarding this species' habitat selection during the winter months. In 2020–2022, we equipped 22 P. sinensis with radio transmitters (VHF), and we successfully relocated 13 turtles, 11 of which were buried in submerged substrates and 2 buried in terrestrial soil for hibernation. In aquatic habitats, turtles preferred ponded areas formed during the dry period of the Yellow River with low water velocity and less anthropogenic disturbance. However, we found little evidence for the selection of dissolved oxygen levels. In terrestrial habitats, turtles are buried under densely vegetated soils with their dorsal carapace approximately 5 cm beneath the surface, allowing respiration through a protruded neck. Terrestrial hibernacula were close to the water, maintained more than 30% humidity throughout the winter, and were effectively protected against freezing. To the best of our knowledge, this is the first formal report of the behavior of terrestrial hibernation in softshell turtles. Our results suggest that P. sinensis has selectivity toward hibernation habitats with specific microenvironmental characteristics, indicating that protection of the characterized habitats provided in this study is important for the future conservation of this threatened softshell turtle species.

Plants evolve diverse communication systems in adapting to complex and variable environments. Here, we examined the relationship between plant architecture, population density and inter-plant communication within tree species. We tested the hypothesis that trees of species with complex architecture or high population density (high population density: HPD) communicate among conspecifics via volatiles. In addition, we hypothesize that states of mycorrhizal symbiosis (arbuscular mycorrhizal or ectomycorrhiza) which relation to population density can predict the development of interplant communication in trees. We tested induced defense as an indicator of communication in saplings of nine tree species with various complexities of architecture (number of leaves per shoot) and either low (low population density: LPD) or HPD, either exposed for 10 days to volatiles from a damaged conspecific or not exposed. We evaluated the number of insect-damaged leaves and the area of leaf damage on these trees after 1 and 2 months in the field. Most exposed HPD trees had less leaf damage than controls. However, LPD trees did not differ in leaf damage between treatments. These results are partially supported by plant hormone analysis. In addition, the presence of inter-plant communication was positively correlated with both the number of leaves per shoot (complexity of plant architecture) and population density. The analysis which combined results of previous studies suggests that states of mycorrhizal symbiosis predict the development of interplant communication; interplant communication is common in ectomycorrhiza species. These results suggest the importance of plant architecture and population density as well as state of mycorrhizal symbiosis in the development of interplant communications within tree species.

The Sierra Madre Oriental (SMO) is a significant mountain range and one of Mexico's 14 biogeographical provinces. Its delimitation has been debated. This study aims to analyze the distribution of plants, beetles, odonates, amphibians, reptiles, and mammals using an endemicity analysis to identify endemism areas and confirm the SMO's biogeographical units. Georeferenced data for 326 species distributed in the Sierra Madre Oriental were compiled using QGIS software, and an endemicity analysis (EA) was carried out with NDM-VNDM to evaluate taxon distribution congruence in predefined grids. Different grid sizes and specific parameters were used to identify areas of endemism, with an Endemicity Index (EI) assigned to measure the consistency of these areas. Six main areas of endemism (EA) were identified: two in the northern region and four in the southern region of the SMO. These areas are supported by several taxa, except mammals, which did not significantly contribute to the identified AEs. The study suggests new boundaries within the SMO, establishing the Rio Verde as the natural barrier in the north rather than the Moctezuma River. The multi-taxonomic analysis supports dividing the SMO into two subprovinces, proposing a new delimitation based on the distribution of species with different dispersal capacities. This new regionalization can be useful for prioritizing conservation areas and designing more effective strategies. Future research should include more distribution data of mammals and birds to strengthen these results and better define the subprovinces and biogeographical districts of the SMO.