Impact of climate change on the distribution of Sal species

Mapping the potential spatial distribution for offshore finfish aquaculture in China under climate change

Evaluating the impact of future climate and forest cover change on the ability of Southeast (SE) Asia’s protected areas to provide coverage to the habitats of threatened avian species

The success of a species in future climate change scenarios depends on its morphological, physiological, and demographic adaptive responses to changing climate. The existence of threatened species against climate adversaries is constrained due to their small population size, narrow genetic base, and narrow niche breadth. We examined if ecological niche model (ENM)-based distribution predictions of species align with their morpho-physiological and demographic responses to future climate change scenarios. We studied three threatened Ilex species, viz., Ilex khasiana Purkay., I. venulosa Hook. f., and I. embelioides Hook. F, withrestricted distribution in Indo-Burma biodiversity hotspot.Demographic analysis of the natural populations of each species in Meghalaya, Indiarevealed an upright pyramid suggesting a stable population under the present climate scenario. I. khasiana was confined to higher elevations only while I. venulosa and I. embelioides had wider altitudinal distribution ranges. The bio-climatic niche of I. khasiana wasnarrow, while the other two species had relatively broader niches. The ENM-predicted potential distribution areas under the current (2022) and future (2050) climatic scenarios (General Circulation Models (GCMs):IPSL-CM5A-LR and NIMR-HADGEM2-AO) revealed that the distribution of highly suitable areas for the most climate-sensitive I. khasiana got drastically reduced. In I. venulosa and I. embelioides, there was an increase in highly suitable areas under the future scenarios. The eco-physiological studies showed marked variation among the species, sites, and treatments (p < 0.05), indicating the differential responses of the three species to varied climate scenarios, but followed a similar trend in species performance aligning with the model predictions.

Rare, Endemic and Threatened (RET) species with naturally small populations are always at high risk of extinction, especially during the climate change process. Climate change phenomena are also identified as a strong driver in the habitat shift of many medicinal and aromatic plants (MAPs). The expected consequences of climate change are so dangerous that some key species can move to extinction. Therefore, the quest for suitable habitats of such species is taken as a challenge by various ecologists and conservationists. This study aims to predict the suitable habitats of Elwendia persica (Boiss.) Pimenov & Kljuykov, a threatened species for current and future climatic scenarios in the Indian Himalayan Region (IHR). The assessments for current and future climatic scenarios are accessed on the optimistic Representative Concentration Pathway 4.5 (RCP 4.5). The MaxENT algorithm has helped to predict the suitable habitat of the species in the study area. The model has predicted 1.12%, 2.37%, and 0.98% of the total study area as highly suitable habitats in current (2000) and future (2050 and 2070) climatic scenarios. South-eastern facing slopes are considered as the most suitable areas for the species in the Indian Himalayan Region. Our results show that suitable habitats of the species may increase upto 2050, and subsequently decrease.

We investigated tree composition, stand characteristics, biomass allocation pattern and carbon storage variability in Sal forests (Shorea robusta Garten.) under two forest management regimes (Sal forest and Sal plantation) in Tripura, Northeast India. The results revealed higher species richness (29 species), stand density of 1060.00±11.12 stems ha−1 and diversity index (1.90±0.08) in Sal forest and lower species richness (4 species), stand density of 230.00±37.22 stems ha−1 and diversity index (0.38±0.15) in Sal plantation. The total basal cover (33.02±4.87 m2 ha−1) and dominance (0.76±0.08) were found higher in Sal plantation than the Sal forest (22.53±0.38 m2 ha−1 and 0.23±0.02 respectively). The total vegetation carbon density was recorded higher in Sal plantation (219.68±19.65 Mg ha−1) than the Sal forest (167.64±16.73 Mg ha−1). The carbon density estimates acquired in this study suggest that Sal plantation in Tripura has the potentiality to store a large amount of atmospheric carbon inspite of a very low species diversity. However, Sal forests has also an impending sink of carbon due to presence of large number of young trees.

Tilia amurensis Rupr (T. amurensis) is one endangered and national class II key protected wild plant in China. It has ornamental, material, economic, edible and medicinal values. At present, the resources of T. amurensis are decreasing, and the prediction of the distribution of its potential habitat in China can provide a theoretical basis for the cultivation and rational management of this species. In this study, the R language was used to evaluate 358 distribution records and 38 environment variables. The MaxEnt model was used to predict the potential distribution areas of T. amurensis under the current and future climate scenarios. The dominant environmental factors affecting the distribution of T. amurensis were analyzed and the Marxan model was used to plan the priority protected areas of this species. The results showed that Bio18, Slope, Elev, Bio1, Bio9 and Bio2 were the dominant environmental factors affecting the distribution of T. amurensis. Under the future climatic scenarios, the potential suitable areas for T. amurensis will mainly distribute in the Northeast China, the total suitable area will reduce compared with the current climate scenarios, and the general trend of the centroid of suitable habitat will be towards higher latitudes. The SPF value of the best plan obtained from the priority conservation area planning was 1.1, the BLM value was 127,616, and the priority conservation area was about 57.61×104 km2. The results suggested that climate, soil and topographic factors jointly affected the potential geographical distribution of T. amurensis, and climate and topographic factors had greater influence than soil factors. The total suitable area of T. amurensis in China under different climate scenarios in the future will decrease, so more effective protection should be actively adopted.

Sesame (Sesamum indicum L, flora of China) is an essential oil crop in China, but its growth and development are affected by climate change. To cope with the impacts of climate change on sesame cultivation, we used the Maximum Entropy (MaxEnt) model to analyze the bioclimatic variables of climate suitability of sesame in China and predicted the suitable area and trend of sesame in China under current and future climate scenarios. The results showed that the MaxEnt model prediction was excellent. The most crucial bioclimatic variable influencing the distribution of sesame was max temperature in the warmest month, followed by annual mean temperature, annual precipitation, mean diurnal range, and precipitation of the driest month. Under the current climate scenario, the suitable areas of sesame were widely distributed in China, from south (Hainan) to north (Heilongjiang) and from east (Yellow Sea) to west (Tibet). The area of highly suitable areas was 64.51 × 104 km2, accounting for 6.69% of the total land area in China, and was primarily located in mainly located in southern central Henan, eastern central Hubei, northern central Anhui, northern central Jiangxi, and eastern central Hunan. The area of moderately suitable areas and lowly suitable areas accounted for 17.45% and 25.82%, respectively. Compared with the current climate scenario, the area of highly and lowly suitable areas under future climate scenarios increased by 0.10%–11.48% and 0.08%–8.67%, while the area of moderately suitable areas decreased by 0.31%–23.03%. In addition, the increased highly suitable areas were mainly distributed in northern Henan. The decreased moderately suitable areas were mainly distributed in Heilongjiang, Jilin, and Liaoning. This work is practically significant for optimizing the regional layout of sesame cultivation in response to future climate conditions.

Two ecologically and economically important, and threatened Dipterocarp trees Sal (Shorea robusta) and Garjan (Dipterocarpus turbinatus) form mono‐specific canopies in dry deciduous, moist deciduous, evergreen, and semievergreen forests across South Asia and continental parts of Southeast Asia. They provide valuable timber and play an important role in the economy of many Asian countries. However, both Dipterocarp trees are threatened by continuing forest clearing, habitat alteration, and global climate change. While climatic regimes in the Asian tropics are changing, research on climate change‐driven shifts in the distribution of tropical Asian trees is limited. We applied a bioclimatic modeling approach to these two Dipterocarp trees Sal and Garjan. We used presence‐only records for the tree species, five bioclimatic variables, and selected two climatic scenarios (RCP4.5: an optimistic scenario and RCP8.5: a pessimistic scenario) and three global climate models (GCMs) to encompass the full range of variation in the models. We modeled climate space suitability for both species, projected to 2070, using a climate envelope modeling tool “MaxEnt” (the maximum entropy algorithm). Annual precipitation was the key bioclimatic variable in all GCMs for explaining the current and future distributions of Sal and Garjan (Sal: 49.97 ± 1.33; Garjan: 37.63 ± 1.19). Our models predict that suitable climate space for Sal will decline by 24% and 34% (the mean of the three GCMs) by 2070 under RCP4.5 and RCP8.5, respectively. In contrast, the consequences of imminent climate change appear less severe for Garjan, with a decline of 17% and 27% under RCP4.5 and RCP8.5, respectively. The findings of this study can be used to set conservation guidelines for Sal and Garjan by identifying vulnerable habitats in the region. In addition, the natural habitats of Sal and Garjan can be categorized as low to high risk under changing climates where artificial regeneration should be undertaken for forest restoration.

Predicting the impact of climate change on the distribution of two relict Liriodendron species by coupling the MaxEnt model and actual physiological indicators in relation to stress tolerance

Managing storm water under climate uncertainty is a major concern in urban areas throughout the world. There were several floods events recorded in Chennai, a one of the major metropolitan coastal city in India. The flood incidences were repeatedly reported in recent decades. In this study, the existing state of storm water drains are evaluated under current and future climate scenarios in one of the most flood-prone areas of Chennai viz. Velachery zone. The mitigation measures are recommended to increase its resilience against floods. The Intergovernmental Panel on Climate Change (IPCC) CMIP5 models of Representative Concentration Pathways (RCP) 4.5 are used to develop possible future climate change scenarios of the city. The daily rainfall data for the period 1975–2015 obtained from India Meteorological Department are used to find the extremities and to generate Intensity-Duration-Frequency (IDF) curves. The IDF curves are generated for 2, 5, 10, 50, 100 year return period under current and future climate scenarios. The storm drainage network are delineated with Differential Geographic Positioning System (DGPS) survey. The integrated hydraulic and hydrological modelling is carried out to assess the flood carrying capacity of storm drainage under present and future climate scenarios. The vulnerable hotspots are identified and flood mitigation measures are suggested to reduce the flood risk at Velachery.

ABSTRACTHippophae tibetana Schltdl, a valuable plant with significant edible, medicinal, and ecological restoration functions, has long attracted considerable attention. This study, based on the MaxEnt model, combines current and future climate scenarios (2050s and 2070s) to predict the distribution of suitable habitats for H. tibetana. The results demonstrated that the spatial distribution patterns of H. tibetana are primarily governed by the combined effects of key environmental factors, including elevation gradient, annual precipitation variation, and mean annual temperature fluctuation. Modeling results demonstrate that H. tibetana currently occupies 157.62 × 104 km2 of suitable habitats, showing high concentration in three key zones: (1) Qinghai's eastern‐southwestern belt, (2) Gansu's southeastern/Sichuan's western‐southeastern corridor, and (3) Tibet's eastern‐southwestern quadrant. Under future climate scenarios, with increasing temperatures and changes in precipitation patterns, the suitable habitats for Hippophae are generally expected to expand northeastward, particularly in high‐altitude and northwestern regions where the environment becomes more favorable. However, in some extreme climate scenarios, significant changes in temperature and precipitation could have negative effects on the growth and expansion of Hippophae. The study suggests that climate change may drive H. tibetana to expand into more suitable areas, but it may also lead to the reduction or migration of suitable habitats in some regions. Therefore, future ecological conservation and planting plans for Hippophae should fully consider the impact of climate change and adopt flexible adaptive management strategies to ensure its sustainable development in the context of climate change.

Consequences of global climate change are predicted to increase risks to crop production in the future. However, the possible broader impact of climate change on social-ecological systems still needs to be evaluated. Therefore, the present study focuses on one such globally important agricultural social-ecological system referred to as the Village Tank Cascade System (VTCS) in the dry zone of Sri Lanka. The VTCS has considerable potential to withstand seasonal climate variability mainly through continuous supply of water by the village tank storage throughout the year. The current study aimed to investigate trends of climate variability and possible impacts on paddy production in the North and North-central VTCS zone. Observed and projected rainfall and temperature data were analysed to evaluate the past variability trends (1970 to 2020) and model future (up to 2100) scenarios of climate variability and trends. Long-term observed rainfall and temperature data (1946 to 2020) were analysed to identify possible anomalies. The Maximum Entropy (MaxEnt) model has been used to predict the situation of future paddy farming (2050 and 2070) under two climate scenarios (RCP4.5 and RCP8.5) of the Intergovernmental Panel on Climate Change (IPCC). Six variables that would affect paddy growth and yield quality were used alongside the average monthly rainfall and temperature of two Global Climate Models (MIROC5 and MPI-ESM-LR). Climate suitability for two paddy cultivation seasons (Yala and Maha) were predicted for current and future climate scenarios. The findings revealed that observed and projected climate changes show considerable deviation of expected rainfall and temperature trends across the VTCS zone. Temperature exhibits warming of approximately 1.0 °C during the declared Global Warming Period (1970 to 2020) in the study area. In addition, there is a trend of significant warming by 0.02 °C/year, RCP4.5 and 0.03 °C/year, RCP8.5 from 1950 to 2100. Rainfall (1970–2020) shows high interannual variability but trends were not significant and less discernible. However, long-term projected rainfall data (1950–2100) analysis detected a significant (p = 0) upward trend (2.0 mm/year, RCP4.5 and 2.9 mm/year, RCP8.5), which is expected to continue up to the end of this century. Further, the study revealed some shifts in temperature towards higher values and positive anomalies in rainfall affecting seasonality and the likelihood of more extreme occurrences in the future, especially during the Maha cultivation season. The MaxEnt model predicts the following under future climate scenarios: (i) spatio-temporal shifts (conversions) in climate suitability for paddy farming in the VTCS zone; (ii) substantial low and moderate suitability areas that are currently suitable will remain unchanged; (iii) up to 96% of highly suitable and 38% of moderately suitable paddy growing areas in the VTCS zone will be at risk due to a decline in future climate suitability; and (iv) expansion of lower suitability areas by approximately 22% to 37%, due to conversion from moderate suitability areas. The study provides evidence that the continuous warming trend with increasing variability in rainfall and shifting seasonality could increase the vulnerability of future paddy farming in the VTCS. Thus, findings of this study will help planners to make more targeted solutions to improve adaptive capacity and regain the resilience to adjust the paddy farming pattern to deal with predicted climate variability and change.

Melaleuca wetland ecosystems play crucial roles in ecology and human livelihood, yet the ecosystems are vulnerable to climate change and relative sea-level rise (SLR) impacts. Documents and research on climate change and SLR impacts on coastal Melaleuca wetlands in the Mekong Delta, Vietnam, are currently limited. Therefore, the present study aimed to identify changes in habitat suitability for a coastal Melaleuca wetland species in response to different future climate change and SLR scenarios, in the West Sea of the Mekong Delta, with the aid of an ensemble species distribution model (SDM) and the Sea Level Affecting Marshes Model (SLAMM). Melaleuca species occurrence records, bioclimatic and eco-physiological variables were utilized to predict potential distribution of the species in response to current and future climate scenarios (i.e. RCP4.5 and 8.5) for the year 2070. Wetland maps for 2020, a digital elevation model (DEM) and localized site-specific parameters (i.e. historic trend of SLR, erosion, subsidence and overwash) were utilized as input data for SLAMM to simulate spatial distribution of Melaleuca/forested wetlands under the two SLR scenarios. The final habitat suitability for the Melaleuca wetland species was identified based on these two resultant datasets, climatic suitability and spatial distribution of the wetlands. Simulated results suggested mean losses in suitable habitat of 29.8% and 58.7% for stable and subsidence scenarios, respectively, for the year 2070 in comparison to the baseline scenario. SLR combined with considerable subsidence rate was suggested as one of the main drivers responsible for the habitat suitability loss. The findings obtained from the current work are useful sources for planning conservation areas for the Melaleuca wetlands, to protect and preserve the ecosystems and their important services under future climate and SLR scenarios.

Predicting the potential influences of climate change on the richness and distribution is essential for the protection of endangered species. Most orchid species are narrowly distributed in specific habitats and are very vulnerable to habitat disturbance, especially for endangered orchid species on the Qinghai-Tibetan Plateau (QTP). In this study, we simulated the potential influences of climate change on the richness and distribution of 17 endangered orchid species on the QTP using the MaxEnt model based on the shared socioeconomic pathways scenarios (SSPs) in the 2050s and 2070s. The results showed that aspect, annual precipitation, elevation, mean temperature of driest quarter, topsoil pH (H2O), and topsoil sand fraction had a large influence on the potential distribution of endangered orchid species on the QTP. The area of potential distribution for orchid species richness ranging from 6 to 11 under the current climate scenario was 14,462 km2 (accounting for 0.56% of QTP), and it was mostly distributed in the southeastern part of QTP. The area of orchid species richness ranging from 6 to 11 under SSP370 in the 2070s was the smallest (9,370 km2: only accounting for 0.36% of QTP). The largest area of potential distribution for orchid species richness ranging from 6 to 11 was 45,394 km2 (accounting for 1.77% of QTP) under SSP585 in the 2070s. The total potential distribution area of 17 orchid species richness all increased from the 2050s to the 2070s under SSP126, SSP245, SSP370, and SSP585. The orchid species richness basically declined with the increasing elevation under current and future climate scenarios. The mean elevation of potential distribution for orchid species richness ranging from 6 to 11 under different climate scenarios was between 3,267 and 3,463 m. The mean elevation of potential distribution for orchid species richness ranging from 6 to 11 decreased from SSP126 (3,457 m) to SSP585 (3,267 m) in the 2070s. Based on these findings, future conservation plans should be concentrated on the selection of protected areas in the southeastern part of QTP to protect the endangered orchid species.

Assessing the impact of climate change on rainwater harvesting in the Oum Zessar watershed in Southeastern Tunisia