Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography

Species climate niche models (CNMs) have been widely used for assessing climate change impact, developing conservation strategies and guiding assisted migration for adaptation to future climates. However, the CNMs built based on species occurrence data only reflect the species’ realized niche, which can overestimate the potential loss of suitable habitat of existing forests and underestimate the potential of assisted migration to mitigate climate change. In this study, we explored building a fundamental climate niche model using widely available species occurrence data with two important forest tree species, lodgepole pine (Pinus contorta Dougl. ex Loud.) and Douglas-fir (Pseudotsuga menziesii Franco.), which were introduced to many countries worldwide. We first compared and optimized three individual modeling techniques and their ensemble by adjusting the ratio of presence to absence (p/a) observations using an innovative approach to predict the realized climate niche of the two species. We then extended the realized climate niches to their fundamental niches by determining a new cut-off threshold based on species occurrence data beyond the native distributions. We found that the ensemble model comprising Random Forest and Maxent had the best performance and identified a common cut-off threshold of 0.3 for predicting the fundamental climate niches of the two species, which is likely applicable to other species. We then predicted the fundamental climate niches of the two species under current and future climate conditions. Our study demonstrated a novel approach for predicting species’ fundamental climate niche with high accuracy using only species occurrence data, including both presence and absence data points. It provided a new tool for assessing climate change impact on the future loss of existing forests and implementing assisted migration for better adapting to future climates.

We aim to understand ontogenetic shifts in habitat use and feeding patterns by 2 fish species, Lutjanus fulviflamma and L. ehrenbergii, within a tropical seascape in East Africa. Stomach contents and stable isotope signatures of muscle tissues (δ13C and δ15N) were compared between and within species. Fish of all life stages and potential food items were sampled from mangrove creeks, seagrass beds, and coral reefs around Mafia Island, Tanzania. Due to similarities in morphology between species, correct species identity was confirmed using genetic barcoding (mtDNA, partial sequence of cytochrome oxidase subunit I [COI]). Stable isotope analysis in R (based on mixing models) confirmed that δ13C and δ15N values in L. fulviflamma and L. ehrenbergii reflected those of prey items caught in different habitats. Diets and mean δ13C and δ15N values of muscle tissue differed between life stages of fish, indicating ontogenetic changes in habitat and diet. L. fulviflamma and L. ehrenbergii differed in diet and δ13C and δ15N values of muscle tissue, although they overlapped in habitat use, suggesting food resource partitioning between the 2 species. Furthermore, diet overlap indexes were low between subadult species in mangrove and seagrass or coral habitats. L. fulviflamma displayed a diet shift with decreasing importance of small crustaceans in juveniles and an increasing importance of prey fishes in subadults and adults. L. ehrenbergii showed the opposite pattern. The study verifies feeding interlinkage within the mangrove-seagrass-coral reef continuum in Mafia Island by providing strong evidence of ontogenetic migration. Understanding these connections will enhance our ability to manage tropical seascapes, and highlights the need to include multiple habitats in marine protected areas.

AimSpecies delimitation is the basis for identifying diversity, and the genetic structure and demographic history of species can shed light on the effects of geological and historical climate change, thus allowing us to develop appropriate conservation and management strategies. In this study, we aimed to clarify the species composition and geographic distribution of the Odorrana schmackeri complex in the karst areas of Guizhou, explore the influence of geological and climatic events on its evolutionary and demographic history, predict the impact of future climate on the distribution area, and investigate the ecological niche differentiation of the complex.LocationKarst areas of Guizhou Province, China.MethodsUsing three mitochondrial (12S, 16S, and ND2) and four nuclear gene (BDNF, RAG1, RAG2, and Tyr) sequences as genetic markers, Bayesian inference (BI) was used to infer phylogenetic relationships and BEAST was used to assess divergence times. We assessed and estimated demographic histories using neutrality tests, mismatch distributions, and Bayesian skyline plots (BSPs). Using a species distribution prediction model, past and future suitable ranges were assessed. Niche equivalency and similarity of the three species of the complex were examined using the R package “ecospat.”ResultsThe O. schmackeri complex in Guizhou Province consists of three species: O. kweichowensis, O. huanggangensis, and O. hejiangensis. Demographic analyses indicated that population expansion of O. kweichowensis and O. huanggangensis occurred during the late Pleistocene, coinciding with the expansion of suitable habitat during the last ice age and the mid‐Holocene. Our projections suggest that potentially suitable habitat for all three species will contract under all future climate scenarios. The ecological niche similarity test showed significant climatic ecological niche differentiation between O. huanggangensis and O. kweichowensis, and between O. kweichowensis and O. hejiangensis.Main conclusionsThe Guizhou distribution of the O. schmackeri complex comprises three species, most of whose recent common ancestors diverged at the early Miocene (ca. 14.30 Ma) and split at the late Miocene (ca. 8–9 Ma). The Miaoling Mountains were not a geographical barrier to the dispersal of O. kweichowensis and O. huanggangensis, and the Dalou Mountains, Foding‐Wuling‐Leigong‐Yueliang Mountains were geographical distribution boundaries in the formation of the current distribution of the three species in Guizhou Province. No population expansion was detected within O. hejiangensis. Population expansion in the late Pleistocene for O. kweichowensis and O. huanggangensis was less affected by the glacial period, and was related to the presence of refugia. Considering future climate change, the focus should be on suitable habitats, mainly in nature reserves. In conclusion, this study highlights the importance of the use of genetic markers for the identification of species in the complex, the small geographical barrier of the Miaoling Mountains, and the conservation of amphibians in karst areas.

Supplementary material 6 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 5 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 4 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 1 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 2 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 7 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 8 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

Supplementary material 3 from: Şahin MK (2025) Ecological niches and climate-driven range shifts in Hemorrhois snakes: implications for biogeography. Herpetozoa 38: 191-204. https://doi.org/10.3897/herpetozoa.38.e151017

With increasing globalization, trade, and human movement, the rate of alien species introduction has increased all around the globe. In addition, climate change is thought to exacerbate the situation by allowing range expansion of invasive species into new areas. Predicting the distribution of invasive species under conditions of climate change is important for identifying susceptible areas of invasion and developing strategies for limiting their expansion. We used Maxent modeling to predict the distribution of one of the world's most aggressive invasive weeds, Ageratina adenophora (Sprengel) R. King and H. Robinson, in the Chitwan–Annapurna Landscape (CHAL) of Nepal under current conditions and 3 future climate change trajectories based on 3 representative concentration pathways (RCPs 2.6, 4.5, and 8.5) in 2 different time periods (2050 and 2070) using species occurrence data, and bioclimatic and topographic variables. Minimum temperature in the coldest month was the most important variable affecting the distribution of A. adenophora. About 38% (12,215 km2) of the CHAL area is climatically suitable for A. adenophora, with the Middle Mountain physiographic region being the most suitable one. A predicted increase in current suitable areas ranges from 1 to 2% under future climate scenarios (RCP 2.6 and RCP 8.5). All protected areas and 3 physiographic regions (Siwaliks, High Mountain, High Himalaya) are likely to gain climatically suitable areas in future climate scenarios. The upper elevational distribution limit of the weed is expected to expand by 31–48 m in future climate scenarios, suggesting that the weed will colonize additional areas at higher elevations in the future. In conclusion, our results showed that a vast area of CHAL is climatically suitable for A. adenophora. Expected further range expansion and upslope migration in the future make it essential to initiate effective management measures to prevent further negative impacts of this invasive plant.

Seeing from space makes sense: Novel earth observation variables accurately map species distributions over Himalaya

Simple SummaryClimate change poses a significant threat to ecologically important fish species, underscoring the need to predict potential shifts in their distributions. Using ensemble species distribution models based on occurrence data from GBIF and OBIS, we assessed the current and future distributions of Collichthys lucidus, Konosirus punctatus, and Clupanodon thrissa in East Asia under present and future climate scenarios. Key environmental predictors were dissolved oxygen and salinity for C. lucidus and chlorophyll and phosphate for K. punctatus and C. thrissa. Projections indicated a contraction of suitable habitats for C. lucidus, in contrast to range expansions for K. punctatus and C. thrissa. Given the limited protection of these species by existing marine protected areas (MPAs), our findings highlight the urgent need for adaptive conservation strategies, including the expansion and reconfiguration of MPAs to safeguard future habitats.The vulnerability of ecologically important fish species to climate change underscores the need to predict shifts in their distributions and habitat suitability under future climate scenarios. In this study, we modeled the potential distribution ranges of three ecologically important fish species (Collichthys lucidus, Konosirus punctatus, and Clupanodon thrissa) across East Asia using a species distribution modeling framework under both current and projected future climate scenarios. Occurrence data were obtained from the Global Biodiversity Information Facility (GBIF) and the Ocean Biodiversity Information System (OBIS), while environmental data were retrieved from the Bio-ORACLE database. Our models demonstrated high predictive performance (AUC > 0.88). Results showed that dissolved oxygen and salinity were the strongest bioclimatic predictors for C. lucidus, whereas chlorophyll and phosphate primarily shaped the distributions of K. punctatus and C. thrissa. Model projections indicated a decline in suitable habitats for C. lucidus, particularly under high-emission scenarios, and range expansions for K. punctatus and C. thrissa toward higher latitudes and nutrient-enriched waters. Highly suitable habitats were concentrated along coastlines within exclusive economic zones, exposing these species to significant anthropogenic pressures. Conservation gap analysis revealed that only 7%, 2%, and 6% of the distributional ranges of C. lucidus, C. thrissa, and K. punctatus, respectively, are currently encompassed by marine protected areas (MPAs). Our study further identified climatically stable regions that may act as climate refugia, particularly for C. lucidus in the Yellow and East China seas. Our findings highlight the urgent need for adaptive management, including the expansion and reconfiguration of MPAs, transboundary conservation initiatives, stronger regulation of exploitation, and increased public awareness to ensure the resilience of fisheries under future climate change.

In recent years, climate change has become a major threat and has been widely documented in the geographic distribution of many plant species. However, the impacts of climate change on the distribution of ecologically vulnerable medicinal species remain largely unknown. The identification of a suitable habitat for a species under climate change scenario is a significant step towards the mitigation of biodiversity decline. The study, therefore, aims to predict the impact of current, and future climatic scenarios on the distribution of the threatened Garcinia indica across the northern Western Ghats using Maximum Entropy (MaxEnt) modelling. The future projections were made for the year 2050 and 2070 with all Representative Concentration Pathways (RCPs) scenario (2.6, 4.5, 6.0, and 8.5) using 56 species occurrence data, and 19 bioclimatic predictors from the BCC-CSM1.1 model of the Intergovernmental Panel for Climate Change’s (IPCC) 5th assessment. The bioclimatic variables were minimised to a smaller number of variables after a multicollinearity test, and their contributions were assessed using jackknife test. The AUC value of 0.956 ± 0.023 indicates that the model performs with excellent accuracy. The study identified that temperature seasonality (39.5 ± 3.1%), isothermality (19.2 ± 1.6%), and annual precipitation (12.7 ± 1.7%) would be the major influencing variables in the current and future distribution. The model predicted 10.50% (19318.7 sq. km) of the study area as moderately to very highly suitable, while 82.60% (151904 sq. km) of the study area was identified as ‘unsuitable’ or ‘very low suitable’. Our predictions of Climate change impact on habitat suitability suggest that there will be a drastic reduction in the suitability by 5.29% and 5.69% under RCP 8.5 for 2050 and 2070, respectively. Objective and SignificancePrimary objective of this study is to identify the potential distribution of medicinally and ecologically important but threatened Garcinia indica species in the northern Western Ghats on the basis of species occurrence data and nineteen bioclimatic predictors. Using MaxEnt modelling, current and future species distribution and suitability has been predicted using the BCC-CSM1.1 and four RCP scenarios of 2.6, 4.5, 6.0, and 8.5. The results also signify the bioclimatic variables contribution to the species distribution in northern Western Ghats.Finally, the results signify that the model might be an efficient tool for biodiversity protection, ecosystem management, and species re-habitation planning under future climate change scenarios.