To synthesise current understanding of overfitting as a pervasive and often underdiagnosed problem in correlative ecological niche models (ENMs), and to assess its consequences for model interpretation, generalisation and transferability under contemporary data and methodological practices.
Worldwide.
We reviewed the ENM literature, synthesising theoretical and empirical studies that address the detection and treatment of overfitting. We examined diagnostic approaches, including spatially and environmentally structured cross-validation, and evaluated modelling practices related to sampling bias, predictor choice, study area definition, model complexity and regularisation.
Common warning signs of overfitting include large discrepancies between training and testing performance, fragmented or ecologically implausible prediction maps and unrealistic response curves. Spatially and environmentally structured cross-validation approaches are effective for assessing data independence and diagnosing inflated performance estimates. Although multiple mitigation strategies can reduce overfitting, the persistent lack of generalisation often reflects limitations related to data quality, spatial and environmental scale, and violated ecological assumptions rather than modelling choices alone.
Predictive accuracy alone is insufficient for evaluating correlative ENMs. Ecological plausibility, interpretability and consistency with known species distributions are equally important for assessing model reliability. We advocate for iterative model evaluation, explicit consideration of ecological assumptions, and transparent reporting as best practices to improve the trustworthiness and transferability of ENMs in ecological research and conservation planning.
Long-term dispersal ability fundamentally shapes genetic structure and biogeographic patterns, yet its role in driving divergence between closely related species with contrasting ranges remains less explored. Here, we assess its influence on genetic differentiation and range dynamics in two Eremias lizards, the widespread E. argus and the narrowly distributed E. brenchleyi.
Northeast, Central North, and Northwest China.
Mongolia racerunner Eremias argus and Ordos racerunner Eremias brenchleyi (Sauria: Lacertidae).
We sequenced two mitochondrial (COI and cyt b) genes from 240 E. argus and 98 E. brenchleyi adults across their Chinese ranges, performed phylogenetic analyses using Maximum Likelihood and Bayesian Inference, assessed genetic diversity and differentiation via haplotype metrics and pairwise FST, and projected suitable habitats under past, present and future climates using ensemble species distribution models (SDMs).
The two species diverged approximately 4.28 million years ago. Eremias brenchleyi exhibited strong isolation-by-distance, high genetic differentiation, and limited post-LGM (Last Glacial Maximum) demographic expansion, indicating topography-constrained dispersal. In contrast, E. argus showed higher genetic connectivity and rapid expansion from the late LGM to the post-glacial period. SDMs indicate that E. argus expanded following the LGM, while E. brenchleyi persisted in restricted ranges. By 2070, both species are projected to expand northward under SSP2-4.5 and SSP5-8.5, with E. brenchleyi benefiting more from warming in net range gain.
Long-term dispersal ability, interacting with landscape and climate, drives genetic and biogeographic divergence. Eremias brenchleyi remains vulnerable to isolation and genetic erosion, while E. argus is threatened by climate-driven range loss. Their contrasting responses underscore the necessity of integrating genetic and environmental data to understand species resilience under climate change.
Renner recently offered a historical overview of Alexander von Humboldt and Aimé Bonpland's expeditions in the Tropical Andes and raises concerns regarding Siqueira-Silva and colleagues, previously published in this journal. We clarify that these concerns arise from a misinterpretation of our data sources and analytical framework. Our study did not incorporate von Humboldt and Bonpland's collections, vegetation belts, or the Tableau Physique des Andes (TPA) into analyses or inferences. The initial species list was based on 21st century expeditions to Mt. Chimborazo and taxonomically standardised. All occurrence data were obtained from georeferenced GBIF records, and final analyses were conducted using 109 well-performing species distribution models. Elevational belts were defined using the variable itself on Mt. Chimborazo, independent of historical classifications. While acknowledging importance of historical perspectives, our results rely on contemporary data and are consistent with the global literature on climate change impacts on mountain biodiversity.
Body size has been used thoroughly in arthropod ecology as a reliable trait to assess fitness responses to changes in environmental factors. We aim to assess general patterns of intraspecific body size variation along macroecological gradients in arthropods. We more specifically discuss these patterns in spiders, as they represent a large and diverse group, colonising most terrestrial habitats.
Location: Global.
Time Period: 1982–2024.
Major Taxa Studied: Arthropods.
We propose a systematic review and a meta-analysis of 146 studies on intraspecific body size variation in arthropods over two main macroecological spatial gradients—latitude and elevation—both of high interest in a global warming context.
We found that more species with direct than with indirect development present a converse Bergmann cline along both gradients.
We propose that life history traits such as voltinism, mobility and brood care influence intraspecific body size patterns—potentially hiding large-scale patterns. This review gathers empirical data about body size variation along elevational and latitudinal gradients in arthropods, providing a step forward to a better understanding of the underlying mechanisms driving body size variation.
Small pelagic species constitute a critical component of fishery resources in the northwest Pacific Ocean. Understanding the interactions among interspecific relationships, environmental niches, and resource abundance is essential for developing science-based fisheries management. This study aims to investigate the differential habitat responses of small pelagic species in the Northwest Pacific to environmental factors, specifically evaluating the ecological interpretation of interspecific relationships through joint species distribution modelling.
The northwest Pacific Ocean.
Japanese sardine; Chub mackerel; neon flying squid.
This study examined three economically important small pelagic species from the northwest Pacific Ocean: Japanese sardine (Sardinops melanostictus), chub mackerel (Scomber japonicus) and neon flying squid (Ommastrephes bartramii). Using a joint species distribution model (JSDM) and ecological niche theory, we integrated multiple environmental variables to analyse interspecific associations and patterns of synchronous habitat variation among these species.
The JSDM accurately predicted suitable habitats for all three species, revealing spatial synchrony in habitat suitability. Notably, a positive interspecific (0.9) association is observed between S. melanostictus and S. japonicus, while both exhibit negative associations (−0.84 and −0.95) with O. bartramii. The breadth of suitable ecological niches for key environmental factors and their corresponding response curves offers ecological insights into these interspecific interactions, confirming the dynamic variations in suitable habitat ranges for these species.
The interspecific relationships reflected similar species responses to environmental factors and highlighted their occupation of overlapping ecological niches. This consistency in environmental responses may drive synchronised habitat shifts, potentially affecting fluctuations in small pelagic species abundance.
We tested whether the inverse latitudinal diversity gradient (LDG) observed for trematode parasites in first-intermediate snail hosts extends to second-intermediate and definitive host taxa.
Sub-tropical to temperate latitudinal zones (±23°–47.6°) in North and South America.
Trematode parasites (Class: Digenea); crustacean second-intermediate hosts (Infra-order: Brachyura; Anomura); fish second-intermediate hosts (Class: Actinopterygii); and fish final hosts (Class: Actinopterygii).
Using meta-analysis, we reviewed and synthesised existing evidence on trematode prevalence across latitudes, focusing on studies that reported these parasites in intertidal species of crustaceans and cryptobenthic fishes. We evaluated whether infection prevalence at the second-intermediate and final host stages followed an inverse LDG.
Evidence indicates that trematode prevalence in second-intermediate and definitive hosts is greater at higher latitudes, consistent with an inverse LDG. This is counter to expectations given the higher diversity of potential hosts near the equator.
Trematode parasites may exhibit an inverse LDG due to temperature-dependent coevolutionary dynamics. At lower latitudes, higher temperatures likely increase parasite virulence, leading to greater parasite-induced mortality and reduced parasite persistence. More research is needed that quantifies trematode prevalence in the same hosts from tropical to temperate latitudinal zones, as broader biogeographic studies would offer insight into Red Queen dynamics.
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：