Precipitation Of Driest Month Research Articles

Predicting the current and future suitable distribution range of Trilocha varians (Walker, 1855) (Lepidoptera: Bombycidae) in China.

Trilocha varians is one of the major pests of Ficus spp. Based on 19 bioclimatic variables provided by the Worldclim, our study analysed the suitable distribution areas of T. varians under current and future climate changes (SSP1-2.6, SSP2-4.5, SSP5-8.5) for two periods (the 2050s and 2090s) using the maximum entropy algorithm (MaxEnt) model. Key environmental variables affecting the geographic distribution of T. varians were also identified, and the changes in the area of suitable range under current and future climate changes were compared. The results showed that the key environmental variables affecting the distribution of T. varians were temperature and precipitation, comprising annual mean temperature (bio1), temperature seasonality (standard deviation × 100) (bio4), precipitation of driest month (bio14), and precipitation of driest quarter (bio17). Under the current climatic conditions, the suitable distribution area of T. varians is within the range of 92°13'E-122°08'E, 18°17'N-31°55'N. The current high, medium, and low suitable areas for T. varians predicted by the MaxEnt model are 14.00 × 104, 21.50 × 104, and 71.95 × 104 km2, of which the high suitable areas are mainly distributed in southern Guangdong, southwestern Guangxi, western Taiwan, Hong Kong, and Hainan. Under different future climatic conditions, some of the high, medium, and low suitability zones for T. varians increased and some decreased, but the mass centre did not migrate significantly. The Pearl River Basin is predicted to remain the main distribution area of T. varians.

Adaptive Distribution and Vulnerability Assessment of Endangered Maple Species on the Tibetan Plateau

Climate change has had an almost irreversible impact on the distribution patterns of tree species on the Tibetan Plateau, driving some vulnerable species to the brink of extinction. Therefore, it is important to assess the vulnerability of tree species in climate-sensitive areas under the following three IPCC-CMIP6 scenarios: SSP126, SSP370, and SSP585. The MaxEnt model was used to predict adaptive distribution for one endangered (Acer wardii W. W. Smith (A. wardii)) and six vulnerable maple plants on the Tibetan Plateau under current and future conditions. We then evaluated their vulnerability using the landscape fragmentation index. Our results showed that the current adaptive areas of vulnerable maple species were mainly distributed in the southeast of the Tibetan Plateau. The dominant factors affecting adaptive areas were temperature annual range (BIO7) for Acer sikkimense Miq. and Acer sterculiaceum Wall.; annual precipitation (BIO12) for Acer cappadocicum Gled.; precipitation of driest month (BIO14) for Acer pectinatum Wall. ex G. Nicholson, Acer taronense Hand.-Mazz., and A. wardii; and subsoil clay fraction (S_CLAY) for Acer campbellii Hook.f. & Thoms. ex Hiern (A. campbellii) Under the three future scenarios, the adaptive areas of maple on the Tibetan Plateau area shifted to the northwest, and habitat suitability increased in the northwestern part of the adaptive areas. In the SSP370 scenario, all seven species showed an increase in adaptive areas, while certain species decreased in some periods under the SSP126 and SSP585 scenarios. The status of the endangered maple species is likely to be even more fragile under the three future scenarios. A. wardii and A. campbellii are more vulnerable and may face extinction, requiring immediate attention and protection. In contrast, the vulnerability of the remaining five species decreased. In conclusion, this study provides recommendations for conserving vulnerable maple species on the Tibetan Plateau. Our data support understanding the distributional changes and vulnerability assessment of these tree species.

Predicting the Distributions of Morus notabilis C. K. Schneid under Climate Change in China

As one of the common mulberry tree species, Morus notabilis C. K. Schneid plays a significant role in various industries such as silkworm rearing, papermaking, and medicine due to its valuable mulberry leaves, fruits, and wood. This study utilizes the maximum entropy (MaxEnt) model to predict the potential distribution of M. notabilis in China under future environmental changes. By integrating the relative percentage contribution score of environmental factors with jackknife test analysis, important variables influencing the distribution of M. notabilis were identified along with their optimal values. The results indicate that Annual Precipitation (bio12), Precipitation of Driest Month (bio14), Min Temperature of Coldest Month (bio6), Temperature Annual Range (bio5–bio6) (bio7), Precipitation of Warmest Quarter (bio18), and Precipitation of Coldest Quarter (bio19) are the primary environmental variables affecting its potential distribution. Currently, M. notabilis exhibits high suitability over an area spanning 11,568 km2, while medium suitability covers 34,244 km2. Both current and future suitable areas for M. notabilis are predominantly concentrated in Sichuan, Yunnan, and Guizhou provinces, as well as Chongqing city in southwest China. Under the SSP5-8.5 scenario representing high greenhouse gas concentrations by 2050s and 2090s, there is an increase in high suitability area by 2952 km2 and 3440 km2, with growth rates reaching 25.52% and 29.74%, respectively. Notably, these two scenarios exhibit substantial expansion in suitable habitats for this species compared to others analyzed within this study period.

Predicting the Potential Distribution Areas of the Asian Redtail Catfi sh (Hemibagrus wyckioides Fang and Chaux, 1949) in the Chao Phraya River, Thailand, using Maximum Entropy Modelling

Hemibagrus wyckioides is recognized as an economically important freshwater fi sh in Thailand. However, there are no available comprehensive data regarding the geographic distribution and habitat suitability of H. wyckioides in Thailand. In addition, its natural population has tended to continuously decrease. This study aimed to predict the suitable distribution areas of H. wyckioides in the Chao Phraya River, Thailand, using the maximum entropy (MaxEnt) algorithm based on climatic factors, including 11 temperature and 8 precipitation indices from the WorldClim database. Model performance was evaluated by the area under the receiver operating characteristic curve (AUC). The jackknife test was used to assess the contribution of each variable to the model. The results revealed that the MaxEnt model performed acceptably well, with an AUC value of 0.939, representing excellent accuracy in predicting the appropriate distribution areas of H. wyckioides in the Chao Phraya River. The potential distribution areas of H. wyckioides were observed mostly along the Chao Phraya River in Sing Buri and Ang Thong Provinces. According to the results of the jackknife test, 11 climatic variables impacted the distribution of H. wyckioides. The annual mean temperature (BIO1), precipitation of driest month (BIO14), and annual temperature range (BIO7) were the most important infl uencing variables, with impact values of 53.5%, 15.9%, and 11.9%, respectively. Therefore, understanding the potential distribution areas can assist researchers in monitoring, management, and conservation activities or with the development of new natural protected areas of H. wyckioides in high-quality areas in the Chao Phraya River.

Impact of climate change on potential distribution of Dickeya zeae causal agent of stalk rot of maize in Sialkot district Pakistan

Maize (Zea mays) is an influential crop in its production across the world. However, the invasion of many phytopathogens greatly affects the maize crop yield at various hotspot areas. Of many diseases, bacterial stalk rot of maize caused by Dickeya zeae results in severe yield reduction, thus the need for efficient management is important. Further, to produce epidemiological information for control of disease outbreaks in the hot spot regions of Sialkot District, Punjab Pakistan, extensive field surveys during 2021 showed that out of 266 visited areas, the highest disease incidence ranging from 66.5 to 78.5% while the lowest incidence was ranging from 9 to 20%. The Maxent modeling revealed that among 19 environmental variables, four variables including temperature seasonality (bio-4), mean temperature of the wettest quarter (bio-8), annual precipitation (bio-12), and precipitation of driest month (bio-14) were significantly contributing to disease distribution in current and coming years. The study outcomes revealed that disease spread will likely increase across four tehsils of Sialkot over the years 2050 and 2070. Our findings will be helpful to policymakers and researchers in devising effective disease management strategies against bacterial stalk rot of maize outbreaks in Sialkot, Pakistan.

Spatio-temporal variation of species richness and phylogenetic diversity patterns for spring ephemeral plants in northern China

Understanding the spatiotemporal distribution of species diversity in response to climatic change is essential for the conservation and management of species resources. Spring ephemeral plants (SEs) have played a crucial role in sustaining the desert and woodland ecosystems of northern China. However, our knowledge regarding the spatiotemporal variation of species diversity in SEs is limited. In this study, we employed occurrence and phylogenetic data for 200 SEs, alongside 19 environmental variables, to model their geographical distribution during the Last Glacial Maximum (LGM), Current, and the year 2070 (considering two representative concentration pathway scenarios, SSP2–4.5 and SSP5–8.5). We also visualized the phylogenetic diversity patterns in the Current. Our findings revealed that more than half of the SEs notably expanded their range and continuously shifted northeastward from LGM to 2070. From LGM to Current and from Current to SSP2–4.5_2070, 64% and 54% of SEs shifted from higher to lower elevations, and 53% of them will slightly shift to higher elevations from Current to SSP5–8.5_2070. We identified three distinct bioregions corresponding to the core ranges of desert SEs and understory SE ecotypes. The Ili Valley, Tacheng Basin, northern and southern Junggar Basin, and Changbai Mountains were identified as hotspots for species richness, phylogenetic diversity, and endemism for the two SE ecotypes. Notably, these hotspots had limited overlap with existing nature reserves. Additionally, the suitable habitat of desert SEs was primarily determined by precipitation seasonality and precipitation of driest month, whereas the distribution of forest understory SEs was mainly influenced by annual precipitation and temperature seasonality. This study significantly contributes to a comprehensive understanding of the modern diversity distribution patterns and conservation priorities for SEs within a species distribution and phylogenetic framework.

Climate change and the future distribution of Brown Planthopper in Indonesia: A projection study

The Brown planthopper, Nilapavarta lugens (Stål) (BPH) is a major pest of rice after the adoption of the Green Revolution. Its outbreaks are frequently linked to climate variability and change, posing almost all rice varieties in Indonesia at risk, resulting in economic losses due to reduced production. The amount of information available about its current and future potential distribution as well as the influencing factors are still limited.The objective of this study is to examine the impact of climate variability on BPH and to assess the projection of the BPH potential distribution under different climate scenarios. Maximum entropy (MaxEnt) was applied to predict the current and future potential distribution of BPH over Indonesia. This study used data on BPH-affected areas, rainfall and temperature, andthe Ocean Nino Index (ONI) on a monthly interval to examine the linkage between climate and BPH affected areas. The global-climate models from phase 6 of coupled model intercomparison project (CMIP6) for period 2041–2060 were used to examine the variations in 19bioclimatic variables for two shared socioeconomic pathways (SSPs) compared to baseline period (1971–2000). The findings concluded that the dynamics of BPH damaged areas were strongly influenced by higher temperature and rainfall in dry season associated with La Niña events. Precipitation of driest month, precipitation seasonality, mean temperature of driest quarter and temperature seasonality were the most affected factors in the distribution of BPH. Our results highlight BPH distribution was expected to increase to 2.4% and 3.02% (moderately suitable), 1.88% and 1.95% (suitable), 2.59% and 2.76% (highly suitable) respectively under SSP2-4.5 and SSP5–8.5. These findings could serve as early warnings to adjust agricultural practices and implement tailored pest management methods to effectively address the shifting pattern of BPH in the future.

Prediction of the potentially suitable areas of Leonurus japonicus in China based on future climate change using the optimized MaxEnt model.

Leonurus japonicus Houtt. is a traditional Chinese medicinal plant with high medicinal and edible value. Wild L. japonicus resources have reduced dramatically in recent years. This study predicted the response of distribution range of L. japonicus to climate change in China, which provided scientific basis for the conservation and utilization. In this study, 489 occurrence points of L. japonicus were selected based on GIS technology and spThin package. The default parameters of MaxEnt model were adjusted by using ENMeva1 package of R environment, and the optimized MaxEnt model was used to analyze the distribution of L. japonicus. When the feature combination in the model parameters is hing and the regularization multiplier is 1.5, the MaxEnt model has a higher degree of optimization. With the AUC of 0.830, our model showed a good predictive performance. The results showed that L. japonicus were widely distributed in the current period. The maximum temperature of warmest month, the min temperature of coldest month, the precipitation of wettest month, the precipitation of driest month, and altitude were the main environmental factors affecting the distribution of L. japonicus. Under the three climate change scenarios, the suitable distribution area of L. japonicus will range shift to high latitudes, indicating that the distribution of L. japonicus has a strong response to climate change. The regional change rate is the lowest under the SSP126-2090s scenario and the highest under the SSP585-2090s scenario.

Potential Distribution of the Asiatic Black Bear in Khangchendzonga National Park, Sikkim Eastern Himalaya using MaxEnt Modeling

Habitat assessment and mapping are major functional keys in the need species conservation concern. The study aimed to understand the possible distribution of Asiatic Black bear (Ursus thibetanus) in the Khangchendzonga National Park. Sign survey, camera trapping, and trail monitoring were used to collect the presence-only data. In this analysis, we used Maximum Entropy Modeling and ArcGIS to determine the variable's contribution to the species distribution and presence. In total, 63 presence data were obtained, and out of 23 environmental variables we used only 15 different environmental variables due to multicollinearity. The ROC results show that variable consistency was excellent (mean AUC=0.941). The variables like Bio-14(Precipitation of driest month), Bio-2(Mean diurnal range (mean of monthly max temp - min temp)), Bio-13(Precipitation of wettest month), aspect and LULC were the critical factors for the distribution of U.thibetanus. The major distribution of U.thibetanus was found in the broadleaved, coniferous forest and grassland patches in the core area. The temperate zone is most preferred as compared to the sub-alpine and alpine zone by U.thibetanus. The distributional area accounts for 360.32km2, representing 20.19% of the whole core area of Khangchendzonga National Park. Large areas of distribution were predicted outside of the core areas, i.e. buffer and transition areas of Khangchendzonga National Park. This study offers valuable findings and data which can be used in future research and conservation management plans in and around Khangchendzonga National Park to mitigate human-bear interaction.

Shifts in the Distribution Range and Niche Dynamics of the Globally Threatened Western Tragopan (Tragopan melanocephalus) Due to Climate Change and Human Population Pressure.

The impact of a changing climate, particularly global warming, often harms the distribution of pheasants, particularly those with limited endemic ranges. To effectively create plans of action aimed at conserving species facing threats such as the Western Tragopan, (Tragopan melanocephalus; Gray, 1829; Galliformes, found in the western Himalayas), it is crucial to understand how future distributions may be affected by anticipated climate change. This study utilized MaxEnt modeling to assess how suitable the habitat of the targeted species is likely to be under different climate scenarios. While similar studies have been conducted regionally, there has been no research on this particular endemic animal species found in the western Himalayas throughout the entire distribution range. The study utilized a total of 200 occurrence points; 19 bioclimatic, four anthropogenic, three topographic, and a vegetation variable were also used. To determine the most fitting model, species distribution modeling (SDM) was employed, and the MaxEnt calibration and optimization techniques were utilized. Data for projected climate scenarios of the 2050s and 2070s were obtained from SSPs 245 and SSPs 585. Among all the variables analyzed; aspect, precipitation of coldest quarter, mean diurnal range, enhanced vegetation index, precipitation of driest month, temperature seasonality, annual precipitation, human footprint, precipitation of driest quarter, and temperature annual range were recognized as the most influential drivers, in that order. The predicted scenarios had high accuracy values (AUC-ROC > 0.9). Based on the feedback provided by the inhabitants, it was observed that the livability of the selected species could potentially rise (between 3.7 to 13%) in all projected scenarios of climate change, because this species is relocating towards the northern regions of the elevation gradient, which is farther from the residential areas, and their habitats are shrinking. The suitable habitats of the Tragopan melanocephalus in the Himalayan region will move significantly by 725 m upwards, because of predicted climate change. However, the fact that the species is considered extinct in most areas and only found in small patches suggests that further research is required to avert a further population decline and delineate the reasons leading to the regional extinction of the species. The results of this study can serve as a foundation for devising conservation strategies for Tragopan melanocephalus under the changing climate and provide a framework for subsequent surveillance efforts aimed at protecting the species.

MODELLING THE POTENTIAL DISTRIBUTIONS OF SAWO KECIK (MANILKARA KAUKI (L.)) DUBARD USING MAXENT TO SUPPORT CONSERVATIONS OF HISTORICAL AND CULTURAL VEGETATIONS IN DAERAH ISTIMEWA YOGYAKARTA PROVINCE

Modelling the potential distributions of Sawo Kecik (Manilkara kauki (L.)) Dubard using MaxEnt to support conservations of historical and cultural vegeta-tions in Daerah Istimewa Yogyakarta Province. Reinwardtia 22(1): 55‒67. — Sawo kecik or Manilkara kauki (L.) Dubard, of the Sapotaceae family as it is formally known, is one of the species with significant cultural values in Yog-yakarta Province (DIY) culture because it symbolizes social righteousness. In connection with this, Yogyakarta's mu-nicipal and district governments have been encouraged to plant sawo kecik. Despite these efforts, there is still a lack of knowledge regarding the possible range of this species, and this knowledge is essential to promoting the conservation of M. kauki in DIY. With the help of isothermality, precipitation of driest month, precipitation seasonality, precipita-tion of driest quarter, and precipitation of warmest quarter data, this study tries to simulate the probable distributions of M. kauki throughout cities and districts in DIY. The model estimated 1,275 km2 of DIY areas was suitable for M. kauki that concentrated in the central parts, spanning from the west to the east of DIY. Yogyakarta City followed by Sleman District has the largest areas categorized from high to very high suitable for M. kauki. While, Gunung Kidul followed by Kulonprogo Districts have the largest areas categorized as low suitable. To conclude, M. kauki can adapt areas with moderate precipitation as low as 20 mm during driest month and as low as 100 mm during driest quarter. During warmest quarter, M. kauki requires precipitation with value of 700 mm. The conservation effort and M. kauki planting should then concentrate on Yogyakarta City and Sleman District since such locations are thought to have high appropriateness for the species.

Effects of Climate Change on the Distribution of Threatened Fishing Bat Myotis pilosus in China.

Climate change and biodiversity loss are two severe challenges that the world is facing. Studying the distribution shifts of species in response to climate change could provide insights into long-term conservation and biodiversity maintenance. Myotis pilosus is the only known fishing bat in East Asia, whereas its population has been decreasing in recent years and it is listed as a "Vulnerable" species. To assess the impact of climate change on the distribution of M. pilosus, we obtained 33 M. pilosus occurrence records within China where they are mainly distributed, and extracted 30 environmental variables. MaxEnt was applied to assess the habitat suitability, recognize the important environmental variables, predict future distribution changes, and identify the potential future climate refugia. The prediction result based on eleven dominant environmental variables was excellent. The Jackknife test showed that the "minimum temperature of coldest month", "precipitation of wettest quarter", "percent tree cover", and "precipitation of driest month" were the main factors affecting the distribution of M. pilosus. The current suitable areas were predicted to be mainly located in southwest and southeast China with a total area of about 160.54 × 104 km2, accounting for 16.72% of China's land area. Based on the CCSM4, it was predicted that the future (2050 and 2070) suitable areas of M. pilosus will expand and shift to high latitudes and altitudes with global warming, but the area of moderately and highly suitable habitats will be small. Considering the dispersal capacity of M. pilosus, the area of colonized suitable habitats in 2050 and 2070 was predicted to be only ca. 94 × 104 km2 and 155 × 104 km2, respectively. The central and southern parts of Hainan, southern Guangdong, central Guizhou, and southern Beijing were identified as potential climate refugia and could be considered as priority conservation areas for M. pilosus. Thus, we suggest long-term monitoring of the priority conservation areas, especially the areas at high latitudes and altitudes. These results contribute to our knowledge of the possible spatial distribution pattern of M. pilosus under current and future climate scenarios, which is important for the population protection and habitat management of this special piscivorous bat species.

Alien flora causes biotic homogenization in the biodiversity hotspot regions of India

Biotic homogenization by invasive alien species is one of the dominant drivers of global environmental change. However, little is known about the patterns of biotic homogenization in global biodiversity hotspots. Here, we fill this knowledge gap by studying the patterns of biotic homogenization and associated geographic and climatic correlates in Indian Himalayan Region (IHR). For this, we use a novel biodiversity database comprising 10,685 native and 771 alien plant species across 12 provinces of the IHR. The database was assembled by screening 295 and 141 studies published from 1934 to 2022 for natives and aliens, respectively. Our results revealed that each native species on average was distributed among 2.8 provinces, whereas the alien species in 3.6 provinces, thereby indicating wider distribution range of alien species in the IHR. The Jaccard's similarity index between the provinces was higher for alien species (mean = 0.29) as compared to natives (mean = 0.16). Addition of alien species pool has homogenized most of the provincial pairwise floras (89.4 %) across the IHR, with greater dissimilarity in their native floras. Our results revealed that the alien species have strong homogenization effect on the provincial floras, regardless of their differences in geographic and climatic distances. The biogeographic patterns of alien and native species richness in the IHR were better explained by a different set of climatic variables, the former by precipitation of driest month and the latter by annual mean temperature. Our study contributes to better understanding of the patterns of biotic homogenization in the IHR and its geographic and climatic correlates. Looking ahead, in an era of Anthropocene, we discuss the wide implications of our findings in guiding biodiversity conservation and ecosystem restoration in global hotspot regions.

Climate and topography controls on soil water-stable aggregates at regional scale: Independent and interactive effects

Detailed information on the variability of soil–water stable aggregates (WSA) is critical for soil management practices, ecosystem services and soil erosion. Topography and climate are two of the most important factors influencing WSA variability at the regional to global scales, especially when soil management, agricultural practices, and soil types are similar, yet few studies have examined their independent and interactive effects on WSA. This work was conducted in the karst region of southwest China to investigate the influence of climatic and topographic variables on WSA variability at the regional scale. A total of 569 topsoil samples (0–20 cm) were collected by random sampling under long-term continuous mono-cropping of tobacco in March 2021. Classical statistics, semivariogram, recursive feature elimination (RFE) algorithm, random forest (RF), and GeoDetector were applied to investigate the relationships between WSA variability and several environmental factors, including 6 topographic, 11 temperature-, and 8 precipitation-related variables. Classical statistics showed that the mean WSA content was 51.67%, varying between 40.84% and 64.05%. Semivariogram analysis revealed the strong spatial autocorrelation of WSA (nugget effect = 10.09%). Based on the REF results, both RF modelling and GeoDetector identified 5 climatic variables, namely isothermality (BIO3), annual precipitation (BIO12), precipitation of wettest month (BIO13), precipitation of driest month (BIO14), and precipitation seasonality (BIO15), which dominated WSA variability at the regional scale. Moreover, the linear and non-linear fits of the key variables to WSA showed that BIO3, BIO12, BIO13, and BIO14 presented highly significantly negative correlations (p < 0.01) with WSA, whereas BIO15 had a highly significantly positive correlation (p < 0.01). The Spearman correlation coefficients of BIO3, BIO12, BIO13, BIO14, and BIO15 with WSA were 0.32, 0.44, 0.3, 0.37, and 0.41, respectively (p < 0.01). The interactive effects between topography and the five key climatic variables could facilitate the interpretation of individual variables for WSA variability. The dominant climatic factors of WSA variability changed along different topographical locations. Overall, this study identifies climatic (mainly precipitation) variables that dominated WSA variability at the regional scale and defines the interactive effects of these variables with topography on WSA variability. The results of this work contribute to explaining the complex causes of soil aggregate stability at large scale and provide clues to the management of soil security under climate change.

Climate Change and Human Activities, the Significant Dynamic Drivers of Himalayan Goral Distribution (Naemorhedus goral).

The distribution of large ungulates is more often negatively impacted by the changing climate, especially global warming and species with limited distributional zones. While developing conservation action plans for the threatened species such as the Himalayan goral (Naemorhedus goral Hardwicke 1825; a mountain goat that mostly inhabits rocky cliffs), it is imperative to comprehend how future distributions might vary based on predicted climate change. In this work, MaxEnt modeling was employed to assess the habitat suitability of the target species under varying climate scenarios. Such studies have provided highly useful information but to date no such research work has been conducted that considers this endemic animal species of the Himalayas. A total of 81 species presence points, 19 bioclimatic and 3 topographic variables were employed in the species distribution modeling (SDM), and MaxEnt calibration and optimization were performed to select the best candidate model. For predicted climate scenarios, the future data is drawn from SSPs 245 and SSPs 585 of the 2050s and 2070s. Out of total 20 variables, annual precipitation, elevation, precipitation of driest month, slope aspect, minimum temperature of coldest month, slope, precipitation of warmest quarter, and temperature annual range (in order) were detected as the most influential drivers. A high accuracy value (AUC-ROC > 0.9) was observed for all the predicted scenarios. The habitat suitability of the targeted species might expand (about 3.7 to 13%) under all the future climate change scenarios. The same is evident according to local residents as species which are locally considered extinct in most of the area, might be shifting northwards along the elevation gradient away from human settlements. This study recommends additional research is conducted to prevent potential population collapses, and to identify other possible causes of local extinction events. Our findings will aid in formulating conservation plans for the Himalayan goral in a changing climate and serve as a basis for future monitoring of the species.

Prediction of global potential suitable habitats of Nicotiana alata Link et Otto based on MaxEnt model

Nicotiana alata Link et Otto, widely used in landscaping, is not only of great ornamental value but also of high commercial and medical value. The global potential habitat of N. alata and the environmental factors affecting its distribution are not that clear at present. To provide a reference for the reasonable and extensive planting of N. alata now and in the future, the MaxEnt model was used to predict its global suitable habitats under current and future climate conditions, respectively, based on global geographic distribution data of N. alata and the current and future world bioclimatic variables. The results showed that mean temperature of the driest quarter (bio9), precipitation of driest month (bio14), precipitation seasonality (bio15) and max temperature of warmest month (bio5), were the key bioclimatic variables governing the distribution of N. alata. The global suitable habitats of N. alata were mainly distributed in Europe, the United States, southeastern South America, and China under current climate conditions. Compared with current climate conditions, the future climate decreased suitable habitats of N. alata under SSP1-2.6, and SSP2-4.5 scenario and increased suitable habitats of N. alata under SSP3-7.0, and SSP5-8.5 climatic scenarios. The results provided valuable information and theoretical reference for the reasonable planting of N. alata.

Effect of Climate Change on the Potentially Suitable Distribution Pattern of Castanopsis hystrix Miq. in China.

Climate warming poses a great threat to ecosystems worldwide, which significantly affects the geographical distribution and suitable growth area of species. Taking Castanopsis hystrix Miq. as the research object, the potentially suitable cultivation regions under present and future climatic emission scenarios in China were predicted based on the MaxEnt model with 360 effective individual distributions and eight environmental variables. The min temperature of coldest month (bio6), precipitation of driest month (bio14), and precipitation of warmest quarter (bio18) are three leading factors affecting the geographical distribution area of C. hystrix Miq. The suitable cultivation regions of C. hystrix Miq. range from 18°-34° N, 89°-122° E in central and southern China and cover an area of 261.95 × 104 km2. The spatial pattern of C. hystrix Miq. will migrate to the southern region of low latitudes with a decreasing suitable area when in ssp1-2.6, and to the southwestern region of low latitudes or expand to the northeast region at high latitudes in ssp5-8.5, with an increasing suitable area; no significant change on the spatial pattern in ssp2-2.4. For ssp1-2.6 or ssp2-4.5 climate scenarios, the southern region of high latitudes will be appropriate for introducing and cultivating C. hystrix Miq., and the cultivation area will increase. For ssp5-8.5, its cultivation will increase and expand to the northeast of high-latitude areas slightly.

Bioclimatic drivers of forage growth and cover in alpine rangelands

ContextClimate change and human activities have significant impacts on the Qinghai–Tibetan Plateau; the alpine ecosystem in this region has been degraded. A decline in forage yield reduces the livestock carrying capacity, but an unmitigated increase may lead to overfeeding and damage to vegetation. These changes have eventually led to grassland degradation and a series of ecological problems. Therefore, it is essential to examine bioclimatic factors that affect forage growth in grasslands.ObjectiveTo identify bioclimatic factors associated with forage growth and coverage in the Qinghai–Tibetan Plateau.MethodsWe examined how forage growth and coverage are affected by 35 bioclimatic indicators published in a global database (CMCC-BioClimInd).Results and conclusionsWe comprehensively considered the relationship between 35 indicators and forage yield and coverage and found that the combination of temperature and precipitation indicators had a very high correlation with yield and coverage. When we evaluated the relationship between each index and forage yield, forage yield was found to be significantly correlated with 16 bioclimatic indices. Forage yield was positively correlated with yearly positive precipitation (R2 = 0.49, p &amp;lt; 0.05), annual precipitation (R2 = 0.48, p &amp;lt; 0.05), and precipitation of driest quarter (R2 = 0.47, p &amp;lt; 0.05), and negatively correlated with temperature seasonality (R2 = 0.52, p &amp;lt; 0.05), precipitation seasonality (R2 = 0.39, p &amp;lt; 0.05), and simplified continentality index (R2 = 0.48). Forage coverage was significantly correlated with 15 bioclimatic indicators. It showed positive correlations with precipitation of driest quarter (R2 = 0.36, p &amp;lt; 0.05), precipitation of driest month (R2 = 0.33, p &amp;lt; 0.05), and annual precipitation (R2 = 0.31, p &amp;lt; 0.05), and negative correlations with temperature seasonality (R2 = 0.415, p &amp;lt; 0.05), annual temperature range, precipitation seasonality, and simplified continentality index (R2 = 0.37, p &amp;lt; 0.05).SignificanceWe identified bioclimatic indicators that affect forage growth in the northeastern Qinghai–Tibetan Plateau, and explored the physiological and ecological mechanisms underlying forage growth. Our results provide a scientific basis for future forage management, early determination of livestock carrying capacity, rational management of animal husbandry practices, and ecological protection and restoration efforts.

Climatic Variability Caused by Topographic Barrier Prevents the Northward Spread of Invasive Ageratina adenophora.

Ageratina adenophora (Spreng.) R.M.King & H.Rob. is one of the most threatening invasive alien plants in China. Since its initial invasion into Yunnan in the 1940s, it spread rapidly northward to southern Mount Nyba in Sichuan, which lies on the eastern edge of the Qinghai-Tibet Plateau. During fieldwork, we found an interesting phenomenon: A. adenophora failed to expand northward across Mount Nyba, even after the opening of the 10 km tunnel, which could have served as a potential corridor for its spread. In this work, to explore the key factors influencing its distribution and spread patterns, we used a combination of ensemble species distribution models with the MigClim model. We found that the temperature annual range (TAR), precipitation of driest month (PDM), highway density (HW), and wind speed (WS) were the most predominant factors affecting its distribution. The north of Mount Nyba is not suitable for A. adenophora survival due to higher TAR. The spatial-temporal dynamic invasion simulation using MigClim further illustrated that the northward invasion of A. adenophora was stopped by Mount Nyba. Overall, Mount Nyba may act as a topographic barrier that causes environmental differences between its south and north sides, preventing the northward invasion of A. adenophora. However, other suitable habitats on the northern side of the mountain still face challenges because A. adenophora is likely to invade via other routes. Therefore, long-term monitoring is needed to prevent human-induced long-distance spread events.

Predicting the changes in suitable habitats for six common woody species in Central Asia.

Climate change over the past decades has significantly altered global hydrothermal conditions and caused an evident shift in species distribution. Predicting species distribution patterns and identifying their influencing factors will be essential in developing coping strategies to prevent species extirpation and extinction. Yet, environmental factors affecting the distribution of woody species in Central Asia remain largely unknown. Here, I used the MaxEnt model to predict the current distributions and future distribution under three SSP-RCP scenarios of six common woody species in Central Asia. The results indicated a good performance of the MaxEnt model. Precipitation of driest month and annual mean temperature were the dominant factors affecting species distribution. For the species with wide ecological niches, i.e., Acer negundo and Rosa chinensis, the suitable areas showed an evident expansion trend under future scenarios. In addition, a trend toward higher elevation was found for the species that grew at high altitudes (1600-3200m). However, the average elevation of suitable area for A. negundo and R. chinensis firstly increased but then decreased under future scenarios. Even though the areas with high species diversity increased from 0.59% under the current situation to 0.82% and 0.81% under ssp245 in 2021-2040 and 2041-2060, respectively, species diversity showed an apparent loss in parts of the northwest and southeast areas under ssp370 and ssp585. This study can guide susceptible habitat protections under climate change.