Predicting the current and future potential spatial distribution of endangered Rucervus eldii eldii (Sangai) using MaxEnt model.

Predicting the current and future suitable habitat distribution of the medicinal tree Oroxylum indicum (L.) Kurz in India

Distribution of Eucalyptus globulus Labill. in northern Spain: Contemporary cover, suitable habitat and potential expansion under climate change

Climate change has already impacted ecosystems and species and substantial impacts of climate change in the future are expected. Species distribution modeling is widely used to map the current potential distribution of species as well as to model the impact of future climate change on distribution of species. Mapping current distribution is useful for conservation planning and understanding the change in distribution impacted by climate change is important for mitigation of future biodiversity losses. However, the current distribution of Chinese caterpillar fungus, a flagship species of the Himalaya with very high economic value, is unknown. Nor do we know the potential changes in suitable habitat of Chinese caterpillar fungus caused by future climate change. We used MaxEnt modeling to predict current distribution and changes in the future distributions of Chinese caterpillar fungus in three future climate change trajectories based on representative concentration pathways (RCPs: RCP 2.6, RCP 4.5, and RCP 6.0) in three different time periods (2030, 2050, and 2070) using species occurrence points, bioclimatic variables, and altitude. About 6.02% (8,989 km2) area of the Nepal Himalaya is suitable for Chinese caterpillar fungus habitat. Our model showed that across all future climate change trajectories over three different time periods, the area of predicted suitable habitat of Chinese caterpillar fungus would expand, with 0.11–4.87% expansion over current suitable habitat. Depending upon the representative concentration pathways, we observed both increase and decrease in average elevation of the suitable habitat range of the species.

The inevitable impacts of climate change have reverberated across ecosystems and caused substantial global biodiversity loss. Climate-induced habitat loss has contributed to range shifts at both species and community levels. Given the importance of identifying suitable habitats for at-risk species, it is imperative to assess potential current and future distributions, and to understand influential environmental factors. Like many species, the Demoiselle crane is not immune to climatic pressures. Khyber Pakhtunkhwa and Balochistan provinces in Pakistan are known wintering grounds for this species. Given that Pakistan is among the top five countries facing devastating effects of climate change, this study sought to conduct species distribution modeling under climate change using data collected during 4 years of field surveys. We developed a Maximum Entropy distribution model to predict the current and projected future distribution of the species across the study area. Future habitat projections for 2050 and 2070 were carried out using two representative concentration pathways (RCP 4.5 and RCP 8.5) under three global circulation models, including HADGEM2-AO, BCC-CSM1-1, and CCSM4. The most influential factors shaping Demoiselle Crane habitat suitability included the temperature seasonality, annual mean temperature, terrain ruggedness index, and human population density, all of which contributed significantly to the suitability (81.3%). The model identified 35% of the study area as moderately suitable (134,068 km2) and highly suitable (27,911 km2) habitat for the species under current climatic conditions. Under changing climate scenarios, our model predicted a major loss of the species' current suitable habitat, with shrinkage and shift towards western-central areas along the Pakistan-Afghanistan boarder. The RCP 8.5, which is the extreme climate change scenario, portrays particularly severe consequences, with habitat losses reaching 65% in 2050 and 85% in 2070. This comprehensive study provides useful insights into the Demoiselle Crane habitat's current and future dynamics in Pakistan.

SummaryAustropuccinia psidii is a biotrophic rust fungus that affects species from the Myrtaceae family. In Mexico, Myrtaceae is widely distributed in temperate, tropical and semi‐arid ecosystems, and includes 20 genera and 192 endemic and exotic species. Austropuccinia psidii has been present in Mexico for the last four decades; however, little is known about the distribution of this rust or the vulnerability of native and exotic Myrtaceae to infection. In this study, we used global occurrence records for the pandemic biotype of myrtle rust to model its current and future suitable habitat using a species distribution model, Maxent. We identified regions that are highly suitable for myrtle rust establishment, now and in the future (2050). Additionally, we identified the Myrtaceae species known to be susceptible to rust infection and that are currently distributed in areas with high rust habitat suitability. Thirty‐six susceptible plant species and 142 untested species are distributed within areas of suitable rust habitat and are considered potentially at risk of rust infection. Current suitable habitat is mainly restricted to the east coast of Mexico, with Veracruz, Puebla, Chiapas, Tabasco and Oaxaca being the most vulnerable regions to the rust under current and future climates. We encourage monitoring within these regions by surveying locations where the rust occurs and within areas with high suitable habitat to determine the threat to native ecosystems and industries reliant on Myrtaceae. We also recommend screening to test the susceptibility of Myrtaceae species with no known susceptibility rating.

Climate change projections in southern Africa show a drier and a warmer future climate. It is not yet clear how these changes are going to affect the suitable habitat of bush encroacher woody species in southern African savannas. Maximum Entropy niche modelling technique was used to test the extent to which climate change is likely to affect the suitable habitat ofVachellia karrooin Zimbabwe based on six Global Climate Models (GCMs) from Coupled Model Intercomparison Project Phase 5 (CMIP5) and two Representative Concentration Pathways (RCPs) for the 2070s. An overlay analysis was then performed in a Geographic Information System based on the current and future bioclimatically suitable areas for the respective GCMs and RCPs. This was done to determine the potential effect of climate change on the focal species. Results show that temperature related variables are more important in explaining the spatial distribution ofV. karroothan precipitation related variables. In addition, results indicate an overall increase in the modelled suitable habitat forV.karrooby the 2070s across the GCMs and RCPs considered in this study. Specifically, the suitable habitat ofV.Karroois projected to increase by a maximum of 57,594 km2signifying a 69% increase from the current suitable habitat (83,674 km2). The suitable areas are projected to increase in eastern, western and south eastern parts of Zimbabwe. These results imply that improved understanding of the response of woody species to a changing climate is important for managing bush encroachment in savanna ecosystems.

Identifying the habitat suitability and built-in corridors for Asiatic black bear (Ursus thibetanus) movement in the northern highlands of Pakistan

Climate change is one of the major threats to global amphibian diversity, and consequently, the species distribution is expected to shift considerably in the future. Therefore, predicting such shifts is important to guide conservation and management plans. Here, we used eight independent environmental variables and four representative concentration pathways (RCPs) to model the current and future habitat suitability of the Korean clawed salamander (Onychodactylus koreanus) and then defined the dispersal limits of the species using cost distance analysis. The current habitat suitability model generated using the maximum entropy algorithm was highly consistent with the known distribution of the species and had good predictive performance. Projections onto years 2050 and 2070 predicted a drastic decrease of habitat suitability across all RCPs, with up to 90.1% decrease of suitable area and 98.0% decrease of optimal area predicted from binary presence grids. The models also predicted a northeastward shift of habitat suitability toward high‐elevation areas and a persistence of suitability along the central ridge of the Baekdudaegan Range. This area is likely to become a climatic refugium for the species in the future, and it should be considered as an area of conservation priority. Therefore, we urge further ecological studies and population monitoring to be conducted across the range of O. koreanus. The vulnerability to rapid climate change is also shared by other congeneric species, and assessing the impacts of climate change on these other species is needed to better conserve this unique lineage of salamanders.

Simple SummaryGrassland caterpillars in the Qinghai-Tibet Plateau (QTP) region are notorious for inflicting severe damage to the alpine meadow ecosystem. Currently, scarce research has been conducted on the spatial distribution patterns and potential habitats for these insect species. A significant difference between the potential habitats of Gynaephora menyuanensis and G. qinghaiensis is reported. The areas of their suitable habitats are significantly and positively correlated with the area of grassland among all land use types of QTP. The potential habitats of both species during the paleoclimate period were located in the eastern and southeastern boundary areas of the QTP. During the paleoclimate period, their potential habitats expanded towards the Hengduan Mountains (low-latitude regions) in the south compared with their current period suitable habitats. With the subsequent temperature rising, their distribution centers were shifted towards the northeast (high-latitude) regions. This study provides an important reference for designating the prevention and control areas for Gm and Gq.This study has systematically investigated and compared the geographical distribution patterns and population density of G. menyuanensis (Gm) and G. qinghaiensis (Gq), which are endemic to the QTP region and inflict severe damage. Using a method combining the BIOMOD2 integration model (incorporating nine ecological niche models) and current species distribution data, this study has compared changes in potential habitats and distribution centers of these two species during ancient, present, and future climate periods and conducted a correlation test on the prediction results with land use types. The study results indicate that there are differences in geographical distribution patterns, distribution elevations, and population density of these two species. Compared with single models, the integration model exhibits prominent accuracy and stability with higher KAPPA, TSS, and AUC values. The distribution of suitable habitats for these two species is significantly affected by climatic temperature and precipitation. There is a significant difference between the potential habitats of these two species. Gm and Gq are distributed in the northeastern boundary area and the central and eastern areas of the QTP, respectively. The areas of their suitable habitats are significantly and positively correlated with the area of grassland among all land use types of QTP, with no correlations with the areas of other land use types of QTP. The potential habitats of both species during the paleoclimate period were located in the eastern and southeastern boundary areas of the QTP. During the paleoclimate period, their potential habitats expanded towards the Hengduan Mountains (low-latitude regions) in the south compared with their current suitable habitats. With the subsequent temperature rising, their distribution centers shifted towards the northeast (high-latitude) regions, which could validate the hypothesis that the Hengduan Mountains were refuges for these species during the glacial period. In the future, there will be more potential suitable habitats for these two species in the QTP. This study elucidates the ecological factors affecting the current distribution of these grass caterpillars, provides an important reference for designating the prevention and control areas for Gm and Gq, and helps protect the alpine meadow ecosystem in the region.

Background: Dalbergia latifolia and Dillenia pentagyna are medicinally significant tree species threatened by habitat loss and climate change. Identifying their current and future suitable habitats is crucial for conservation planning. Methods: We used Maxent (version 3.4.1) ecological niche modelling with 260 occurrence points and 19 bioclimatic variables from the WorldClim dataset to predict the potential distribution of these species in India. Seventy-five percent of the data were used for model training and 25% for testing, with 10 replicates under cross-validation. Future distribution under the 2050 A2a emission scenario was modelled using downscaled climate projections. Results: Maxent performed well, yielding high AUC values of 0.91 for D. latifolia and 0.938 for D. pentagyna, indicating strong predictive performance. The Western Ghats and parts of Central India emerged as the most suitable habitats. Key climatic predictors included minimum temperature of the coldest month and precipitation of the wettest month. Current suitable habitats were estimated at 111,242 km² for D. latifolia and 176,238 km² for D. pentagyna, while future projections indicated a reduction of 38.86% and 40.90% in suitable areas, respectively. Conclusions: Climate change is likely to significantly reduce the suitable habitat for both species by 2050. Conservation strategies should prioritize areas identified through modelling for both in-situ and ex-situ conservation efforts. Ecological niche modelling, as demonstrated here, is a powerful tool for guiding future habitat management and conservation of threatened species.

Climate change threatens the persistence of some plant species, especially those highly adapted to their microclimates. The aim of the study was to determine the current suitable habitat of marula (Sclerocarya birrea subsp. caffra) and to forecast the habitat under different climate change scenarios. Predictions were made in Maxent using 490 occurrence records, four representative concentration pathways (RCPs) and three general circulation models (GCMs). Variables used were altitude, soil characteristics, monthly precipitation, monthly minimum and maximum temperatures and 19 bioclimatic variables. The current suitable habitat of marula largely occurs in mopane and dry miombo woodlands of southern Africa, including Madagascar. Permutation importance test showed that precipitation in November (30.1%), temperature seasonality (22.1%) and mean temperature of wettest quarter (14.3%) contributed significantly to the model of the current suitable habitat. When forecasted, the suitable habitat expanded under all GCMs and RCPs. On average in 2050, the range expanded by 26.0% (RCP2.6), 33.8% (RCP4.5), 24.8% (RCP6.0) and 42.3% (RCP8.5), while in 2070, it expanded by 30.0% (RCP2.6), 39.9% (RCP4.5), 33.3% (RCP6.0) and 45.1% (RCP8.5). The subspecies is not directly threatened by climate change, but indirect threats remain uncertain.

Climate change affects parasitic plants and their hosts on distributions. However, little is known about how parasites and their hosts shift in distribution, and niche overlap in response to global change remains unclear to date. Here, the potential distribution and habitat suitability of four endangered holoparasites and their primary hosts in northern China were predicted using MaxEnt based on occurrence records and bioclimatic variables. The results indicated that (1) Temperature annual range (Bio7) and Precipitation of driest quarter (Bio17) were identified as the common key climatic factors influencing distribution (percentage contribution > 10%) for Cynomorium songaricum vs. Nitraria sibirica (i.e., parasite vs. host); Temperature seasonality (Bio4) and Precipitation of driest month (Bio14) for Boschniakia rossica vs. Alnus mandshurica; Bio4 for Cistanche deserticola vs. Haloxylon ammodendron; Precipitation of warmest quarter (Bio18) for Cistanche mongolica vs. Tamarix ramosissima. Accordingly, different parasite-host pairs share to varying degree the common climatic factors. (2) Currently, these holoparasites had small suitable habitats (i.e., moderately and highly) (0.97–3.77%), with few highly suitable habitats (0.19–0.81%). Under future scenarios, their suitable habitats would change to some extent; their distribution shifts fell into two categories: growing type (Boschniakia rossica and Cistanche mongolica) and fluctuating type (Cynomorium songaricum and Cistanche deserticola). In contrast, the hosts’ current suitable habitats (1.42–13.43%) varied greatly, with highly restricted suitable habitats (0.18–1.00%). Under future scenarios, their suitable habitats presented different trends: growing type (Nitraria sibirica), declining type (Haloxylon ammodendron) and fluctuating type (the other hosts). (3) The niche overlaps between parasites and hosts differed significantly in the future, which can be grouped into two categories: growing type (Boschniakia rossica vs. Alnus mandshurica, Cistanche mongolica vs. Tamarix ramosissima), and fluctuating type (the others). Such niche overlap asynchronies may result in severe spatial limitations of parasites under future climate conditions. Our findings indicate that climate factors restricting parasites and hosts’ distributions, niche overlaps between them, together with parasitic species identity, may jointly influence the suitable habitats of parasitic plants. Therefore, it is necessary to take into account the threatened holoparasites themselves in conjunction with their suitable habitats and the parasite-host association when developing conservation planning in the future.

Predicting the current and future suitable habitats, species distribution, and conservation assessment of Fritillaria dagana (Liliaceae)

Commercial demand is the prerequisite for the expansion of rubber plantation, which is highly dependent on climate, topography, and soil factors. Without the contextual knowledge on these factors, the expansion of rubber plantation would remain unproductive. This study thereby aimed to evaluate the current and future suitable habitat distributions of rubber using maximum entropy (MaxEnt) species distribution model in Xishuangbanna, Southwest China. A total of 148 field-based presence locations and environmental variables (soil, bioclimatic, topography, and land use) were used to predict the suitable areas of rubber plantations using HadGEM2-ES climate model. Medium and high climatic representative concentration pathways (RCPs) (4.5 and 8.5) were selected to predict the suitable habitats for the years 2050 and 2070. Among various factors, annual mean temperature, annual precipitation, precipitation of wettest month, precipitation seasonality, precipitation of warmest quarter, and soil exchangeable H+ contributed significantly to the distribution of rubber. Currently, 1119 km2 and 2716 km2 were predicted as high and moderately suitable areas respectively. It is predicted with increase rates in the high suitable areas, 49.96% and 328.95% by 2050 and 2070 respectively under RCP 4.5. This result indicates that the medium climate change of RCP 4.5 may have a direct positive effect on the expansion of habitat suitability of rubber. We also found potential areas for rubber cultivation in Jinghong and Mengla townships, where the further expansion is anticipated with desirable land-use planning by conserving reserve forest and native vegetation.

Continuing climate change may cause shifts in the adaptive ranges of plant species. But this impact is less understood for many species in the tropics. Here, we examined the distribution of the current and future potential suitable habitats of two native forest spices Piper capense and Aframomum corrorima. We have used MaxEnt software to predict the current and future suitable habitats of these species. Two future climate change scenarios, that is, middle (Representative Concentration Pathway [RCP 4.5]) and extreme (RCP 8.5) scenarios for years 2050 and 2070, were used. A total of 60 and 74 occurrence data of P. capense and A. corrorima, respectively, and 22 environmental variables were included. The effects of elevation, solar radiation index (SRI) and topographic position index (TPI) on suitable habitats of these species were tested using linear model in R. Precipitation of the driest quarter, SRI and TPI significantly affect future suitable habitats of P. capense and A. corrorima. Furthermore, there are significant elevational shifts of suitable habitats for both species under future scenarios (P < 0.001). These novel suitable habitats are located in moist Afromontane and Combretum-Terminalia vegetations. Our results suggest that conservation planning for these species should consider climate change factors including assisted migration.