Ecology and Evolution最新文献

Syzygium alternifolium (Wight) Walp is an ecologically and economically important tree species of dry deciduous forests of the Eastern Ghats. The species is classified as Endangered on the IUCN Red List under the criteria A2cd ver 3.1 due to declining populations threatened by habitat degradation and climate change. This research utilizes MaxEnt-based species distribution modeling to assess its current and future habitat suitability under two future climate scenarios (SSP245 and SSP585) for the years 2050 and 2070, employing the MIROC6 global circulation model. The model demonstrated high performance (AUC = 0.93), with slope, precipitation of the warmest quarter (Bio18), and temperature of the wettest quarter (Bio8) identified as critical predictors. Currently, the extent of suitable habitats is limited (1262.39 km²), with 53.02% situated within protected areas. Projections suggest a steady increase in suitable area, potentially reaching up to 122.87% by 2070 (SSP585), although this expansion is significantly directed towards unprotected landscapes, indicating possible conservation gaps. These results underscore the necessity for proactive initiatives, including long-term monitoring, eco-physiological and genetic evaluations, and the incorporation of distribution modeling results into biodiversity action plans, forest management strategies, and regional climate adaptation frameworks to ensure the species' survival in light of future climate scenarios.

Urbanization poses significant threats to amphibians through habitat loss, fragmentation, and degradation of breeding sites. This study investigated the distribution of two frog species, Dryophytes japonica and Rhacophorus schlegelii, which have relatively similar ecological traits in paddy fields in high-populated, i.e., heavily urbanized areas of Tokyo and Kanagawa, Japan, focusing on landscape- and microhabitat factors simultaneously. Calling surveys were conducted at approximately 100 sites over 2 years (2022–2023) during the breeding season to identify key environmental variables influencing species occurrence. As a landscape factor, both species were positively associated with surrounding forest, suggesting the importance of landscape connectivity between forest as habitats and paddy fields as breeding sites. As a microhabitat factor, water retention in the paddies was a significant factor for both species. Notably, R. schlegelii depended on microhabitat features, in specific soil channels, whereas D. japonica did not. These findings suggest that while both species benefit from nearby forests in urbanized areas, only R. schlegelii is vulnerable to concreting that disrupts soil channels as breeding sites. The study underscores the need for conservation strategies that address both landscape- and microhabitat requirements to support amphibians in urbanizing agricultural regions. Importantly, species with similar ecological niches may respond differently to urban stressors, requiring species-specific management strategies.

Brood parasites improve their reproductive success by offloading the costs of incubation and chick-rearing onto host species. This interaction often triggers an evolutionary arms race between increasingly deceptive brood parasites and increasingly defensive hosts. According to the farming hypothesis, when suitable host nests are limited, some parasitic birds may destroy unsuitable host nests through “Farming behavior” to induce re-nesting, thereby creating new opportunities for parasitism. Despite its potential significance, this behavior has been documented in only a few brood-parasitic species. In 2024, in Jindong County, Pu'er City, Yunnan Province, southwestern China, we successfully captured video evidence of Farming behavior by the Large Hawk-cuckoo (Hierococcyx sparverioides) on its host, the Black-streaked Scimitar Babbler (Pomatorhinus erythrocnemis), and potential host, the Silver-eared Mesia (Leiothrix argentauris). On April 22, 2024, a Large Hawk-cuckoo was recorded removing a 7-day-old Black-streaked Scimitar Babbler chick from its nest, but the chick subsequently crawled back inside. On May 27, 2024, a Large Hawk-cuckoo was observed ejecting three 10-day-old Silver-eared Mesia chicks from their nest. This is the first recorded instance of the Large Hawk-cuckoo removing chicks from the nests of both the host and potential host species. The observed actions are consistent with the Farming hypothesis, suggesting that such behavior may be a more widespread yet underrecognized strategy among brood-parasitic birds.

Hardy–Weinberg equilibrium (HWE) filtering remains widely used in population genomics, but its application remains inconsistent, often lacking detailed justification, and not always aligned with biological context. To evaluate whether conceptual awareness has translated into methodological change, we review empirical studies citing Pearman et al. (2022), a representative study testing the impacts of different grouping approaches for HWE filtering. While pooled filtering is becoming rare, we found a decreasing but still considerable heterogeneity in the decision of filtering schemes, limited reporting of thresholds, and few explicit justifications for applied approaches. These patterns suggest that awareness of HWE filtering limitations is increasing but has not yet led to consistent practice. We synthesise the biological and technical causes of HWE deviation, review recent advances, including population-aware and structure-informed filtering tools, and propose a transparent decision framework for population genomic studies. Rather than a default quality-control step, HWE filtering should be applied as a hypothesis-aware decision that reflects study aims and biological context. A citation-based mini-survey and decision workflow are provided to support biologically informed and reproducible applications.

Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is fatal to some amphibian species, whereas others can carry the pathogen without developing disease. Among the vulnerable species is the Kihansi Spray Toad, Nectophrynoides asperginis, endemic to the Kihansi Gorge spray wetlands in Tanzania's Udzungwa Mountains. By 2009, chytridiomycosis had driven N. asperginis to extinction in the wild, though it survives in captivity. Re-introduction efforts have faced difficulties, underlining the importance of understanding Bd's prevalence in the wild to guide re-introduction programs. Twenty years after Bd was first detected in Tanzania's Kihansi Gorge spray wetlands, we re-evaluated its prevalence and examined whether the pathogen was responsible for the 98% mortality observed among the 1000 captive-bred N. asperginis released there in February 2022. In December 2022, time-constrained surveys were conducted across three spray wetlands covering N. asperginis habitat. Amphibians were skin-swabbed following a protocol developed by the University of California, resulting in two sets of 44 samples from seven species. These samples were analyzed for Bd presence using conventional and real-time quantitative polymerase chain reaction, followed by nucleotide sequencing of PCR products. Bd was detected in 32% of samples, representing four out of the seven species: Arthroleptides yakusini (14%), N. asperginis (9%), Ptychadena anchietae (7%), and Hyperolius substriatus (2%). Whereas N. asperginis was severely affected, the other species did not show signs of the disease. The other three species, namely, Hyperolius mitchelli, Afrixalus fornasinii, and Arthroleptis xenodactyloides, were not detected with Bd. A lineage-specific qPCR diagnostic test confirmed Bd-CAPE as the cause of the mass deaths of the released toads. The continuing presence of Bd-CAPE in the spray wetlands remains a barrier to the successful re-introduction of N. asperginis, necessitating further experimentation to develop strategies for coexistence.

The “dear enemy effect,” wherein territorial animals exhibit reduced aggression toward familiar neighbors compared to strangers, is a widespread strategy to minimize energy expenditure on territory defense. However, whether and how this behavioral capacity varies across with differing vocal complexity remains poorly unclear. We investigated neighbor–stranger discrimination (NSD) in two sympatric tit species that exhibit a stark contrast in song repertoire complexity: coal tits (Periparus ater) and green-backed tits (Parus monticolus). Acoustic analysis revealed that coal tits possessed a large population-level song-type diversity (19 distinct song types) and, crucially, a significantly larger individual syllable repertoire size compared to green-backed tits (5 song types). Playback experiments showed that coal tits exhibited a robust “dear enemy” effect, responding to strangers with significantly closer approach distance and higher flight frequencies near the nest. In contrast, green-backed tits showed uniformly low and undifferentiated responses toward both playbacks of familiar neighbors and strangers, indicating a lack of discrimination. This interspecific divergence was underpinned differences in individual repertoire size and population-level acoustic diversity, with green-backed tits exhibiting higher vocal similarity among individuals. These results demonstrate that the capacity for fine-scale NSD is not universal and suggest that constrained vocal systems—characterized by minimal individual repertoires and high acoustic similarity among individuals—may limit the potential for vocal individual recognition, thereby favoring alternative territorial strategies.

The Indian pangolin (Manis crassicaudata; Manidae, Pholidota), a species categorized as “Endangered” on the IUCN Red List, is one of nine extant pangolin species in Asia. This study investigated habitat preference, habitat suitability, and illegal trade routes of the Indian pangolin in Pakistan's Khyber Pakhtunkhwa province. Habitat preference was determined by analyzing the distribution and density of pangolin signs across various land cover types. Habitat suitability for the species was assessed using the MaxEnt modeling approach and field data. Trade routes were identified using information from hunters, poachers, dealers, and local communities to understand the threats related to illegal wildlife trafficking. Results indicated significant differences in burrow distributions across habitats (χ² = 17.756, df = 6, p < 0.01), which suggest ecological preferences and adaptations. We complemented MaxEnt with Random Forest and Support Vector Machine models trained with the same predictors and spatial folds to validate robustness and characterize non-linear effects. Across held-out folds, SVM performed best, with RF and MaxEnt yielding comparable but lower discrimination; a TSS-weighted ensemble provided a stable consensus SVM (mean AUC ≈ 0.61; TSS ≈ 0.33). Variable-importance and partial-dependence analyses consistently highlighted Elevation, NDMI, and NDWI as influential predictors. Several routes used for the illegal trade of Indian pangolin scales and whole animals were identified. The study also highlights the ongoing issues of illegal poaching and habitat intrusion, worsened by low local awareness and inadequate enforcement. The findings support a comprehensive conservation strategy that includes strict enforcement of wildlife protection laws, increased penalties for poaching, community-based monitoring through targeted awareness campaigns, local wildlife patrols, and ongoing scientific research to support habitat restoration, adaptive management, and evidence-based policy development. Community-based conservation initiatives and improved wildlife law enforcement at key trafficking hubs could significantly reduce poaching pressure.

Environmental DNA (eDNA) technology, as a minimally invasive or noninvasive monitoring approach, has been increasingly applied in biodiversity surveys and ecosystem health assessment by detecting genetic material in environmental samples. This approach exhibits high sensitivity for identifying rare, endangered, and invasive species, with broad applicability across aquatic, terrestrial, and atmospheric ecosystems. Moreover, eDNA metabarcoding enables large-scale detection of microbial community structure and function. By systematically synthesizing multi-environment case studies, this review evaluates optimized eDNA workflows, including sampling (0.22–0.45 μm filtration for aquatic systems, PCI/DNeasy methods for soils, and MD8 samplers for air), DNA extraction, and bioinformatic analysis, integrating standardized guidelines to enhance research reproducibility and comparability. Despite advantages such as reduced field labor and cost efficiency, eDNA applications still face critical challenges, such as reference database gaps, full-process quality control risks, methodological inconsistencies, and limitations in abundance quantification. Future advancements in sequencing technologies, bioinformatics, and interdisciplinary integration (machine learning, remote sensing) are expected to expand eDNA's role in tackling global change issues such as climate adaptation, pollution tracking, and ecological restoration.

For species found in multiple habitats, the problem of camouflage against visually different backgrounds can be challenging. This is particularly so for bird eggs in open nests, as the scope for movement or alternative defensive strategies is limited. We studied egg camouflage in a small shorebird, the Kentish plover Anarhynchus alexandrinus, in two different coastal habitats in Cádiz province, Spain: sandy beaches and saltmarshes. Using calibrated photographs taken in situ and neurophysiologically plausible models of colour and pattern vision, we assessed the predicted discriminability of egg colour and patterning from those of backgrounds for likely nest predators (avian and mammalian carnivore) and, for comparison, humans. The findings suggest that at close range A. alexandrinus eggs are more susceptible to detection by visual predators based on their patterns (aka visual texture) rather than their colours, but at distances beyond which individual pattern elements can be resolved, they are highly cryptic. Although the colours and patterns of the saltmarsh and beach nest sites differ, the colours and surface patterning of eggs do not, suggesting that there is no local adaptation. However, the colours of eggs are similar to the types of background colours that overlap between the beach and saltmarsh. This suggests that, although the gross visual appearances of beach and salt marsh are quite different, egg camouflage in Kentish plovers relies on behavioural nest-site selection and a good colour match to the average location type. The maculation on the eggs does not appear to represent background matching in terms of pattern, so its function remains speculative.

Diatoms play a pivotal role in global biogeochemical cycling and marine primary productivity, making them ideal model organisms for understanding how phytoplankton respond to environmental fluctuations associated with global climate change. In natural marine systems, diatoms frequently encounter simultaneous variations in carbon and nitrogen availability, yet most previous studies have examined the effects of these factors in isolation. To elucidate the integrated transcriptional mechanisms underlying diatom acclimation to coupled carbon–nitrogen (CN) imbalance, we employed RNA sequencing (RNA-Seq) to characterize the global transcriptional response of the model diatom Phaeodactylum tricornutum to high CO₂ (~2000 μatm) and low nitrogen (10% of nitrogen concentration in f/2 medium) under parallel culture conditions. The results revealed both shared and distinct transcriptional responses between the two treatments. Key genes involved in carbon metabolism, such as phosphoglycerate mutase (PGAM_7) and dihydrolipoamide succinyltransferase (PHATRDRAFT_40430), were significantly upregulated, indicating enhanced glycolytic and TCA cycle activity. In contrast, the Calvin-cycle enzyme fructose-1,6-bisphosphatase (FBPC4) was downregulated. Genes associated with nitrogen assimilation-including nitrate reductase (PHATRDRAFT_54983), nitrite reductases (PHATRDRAFT_13154, PHATRDRAFT_8155), and ferredoxin–nitrite reductase (PHATRDRAFT_27757)-were strongly induced under both conditions. Pathway enrichment analysis further indicated the activation of lactic acid fermentation and nitrogen salvage pathways, suggesting a metabolic shift toward energy conservation and nutrient recycling. Collectively, these findings provide an overview of the transcriptional adjustments that enable P. tricornutum to maintain CN homeostasis under high CO₂ and low nitrogen stress, offering new insights into diatom metabolic plasticity under changing ocean conditions.