Predicting changes in the suitable habitats of six halophytic plant species in the arid areas of Northwest China

In the context of changes in global climate and land uses,biodiversity patterns and plant species distributions have been significantly affected.Soil salinization is a growing problem,particularly in the arid areas of Northwest China.Halophytes are ideal for restoring soil salinization because of their adaptability to salt stress.In this study,we collected the current and future bioclimatic data released by the WorldClim database,along with soil data from the Harmonized World Soil Database(v1.2)and A Big Earth Data Platform for Three Poles.Using the maximum entropy(MaxEnt)model,the potential suitable habitats of six halophytic plant species(Halostachys caspica(Bieb.)C.A.Mey.,Halogeton glomeratus(Bieb.)C.A.Mey.,Kalidium foliatum(Pall.)Moq.,Halocnemum strobilaceum(Pall.)Bieb.,Salicornia europaea L.,and Suaeda salsa(L.)Pall.)were assessed under the current climate conditions(average for 1970-2000)and future(2050s,2070s,and 2090s)climate scenarios(SSP245 and SSP585,where SSP is the Shared Socio-economic Pathway).The results revealed that all six halophytic plant species exhibited the area under the receiver operating characteristic curve values higher than 0.80 based on the MaxEnt model,indicating the excellent performance of the MaxEnt model.The suitability of the six halophytic plant species significantly varied across regions in the arid areas of Northwest China.Under different future climate change scenarios,the suitable habitat areas for the six halophytic plant species are expected to increase or decrease to varying degrees.As global warming progresses,the suitable habitat areas of K.foliatum,S.salsa,and H.strobilaceum exhibited an increasing trend.In contrast,the suitable habitat areas of H.glomeratus,S.europaea,and H.caspica showed an opposite trend.Furthermore,considering the ongoing global warming trend,the centroids of the suitable habitat areas for various halophytic plant species would migrate to different degrees,and four halophytic plant species,namely,S.salsa,H.strobilaceum,H.glomeratus,and H.capsica,would migrate to higher latitudes.Temperature,precipitation,and soil factors affected the possible distribution ranges of these six halophytic plant species.Among them,precipitation seasonality(coefficient of variation),precipitation of the warmest quarter,mean temperature of the warmest quarter,and exchangeable Na+significantly affected the distribution of halophytic plant species.Our findings are critical to comprehending and predicting the impact of climate change on ecosystems.The findings of this study hold significant theoretical and practical implications for the management of soil salinization and for the utilization,protection,and management of halophytes in the arid areas of Northwest China.

Influence of Climatic Changes and Anthropogenic Activities on the Distribution and Habitats of Senegalia senegal in Niger: A Forecast and Ecological Analysis

The primary objective of this study is to assess the impact of climate change on the current and future spatial distribution of areas suitable for the growth of Senegalia senegal, a forest species of significant agro-ecological and socio-economic importance. To achieve this objective, the MaxEnt (Maximum Entropy) model was utilized, incorporating species presence points alongside bioclimatic variables. To project future distributions, three climatic models-CCCMA, HadCM3, and CSIRO were employed under the A2 scenario to predict the species’ distribution by the year 2050. Currently, habitats highly favorable for the conservation of the species are situated in the Sahelo-Sudanian and Sudanian zones, accounting for 6.81% of the national territory. All models forecast a substantial increase in habitats highly favorable for the future conservation of S. senegal, with a total expected growth of 448.9%. Conversely, moderately favorable and unfavorable habitats are predicted to decrease by 106.26% and 78.59%, respectively. These findings provide crucial data for the long-term conservation strategy of this species, which holds significant ecological and agronomic potential for the Sahelian region.

Prediction of Suitable Habitat for Lycophytes and Ferns in Northeast China: A Case Study on Athyrium brevifrons

Suitable habitat is vital for the survival and restoration of a species.Understanding the suitable habitat range for lycophytes and ferns is prerequisite for effective species resource conservation and recovery efforts.In this study, we took Athyrium brevifrons as an example, predicted its suitable habitat using a Maxent model with 67 occurrence data and nine environmental variables in Northeast China.The area under the curve(AUC) value of independent test data, as well as the comparison with specimen county areal distribution of A.brevifrons exhibited excellent predictive performance.The type of environmental variables showed that precipitation contributed the most to the distribution prediction, followed by temperature and topography.Percentage contribution and permutation importance both indicated that precipitation of driest quarter(Bio17) was the key factor in determining the natural distribution of A.brevifrons, the reason could be proved by the fern gametophyte biology.The analysis of high habitat suitability areas also showed the habitat preference of A.brevifrons: comparatively more precipitation and less fluctuation in the driest quarter.Changbai Mountains, covering almost all the high and medium habitat suitability areas, provide the best ecological conditions for the survival of A.brevifrons, and should be considered as priority areas for protection and restoration of the wild resource.The potential habitat suitability distribution map could provide a reference for the sustainable development and utilisation of A.brevifrons resource, and Maxent modelling could be valuable for conservation management planning for lycophytes and ferns in Northeast China.

Distribution Prediction of Suitable Growth Area for Eucommia ulmoides in China under Climatic Change Background

[ Objective] The research aimed to study distribution prediction of suitable growth area for Eucommia ulmoides in China under climatic change background. [ Method] By using the maximum entropy model and many kinds of climate change scenarios, we predicted current and future distribution pattems of suitable growth area for Eucommia ulmoides in China and its change process. [ Result ] At present, highly suitable growth area of E. ulmoides mainly distributed in Sichuan, Shaanxi and Chongqing, Under climate change background, total suitable growth areas in future three decades all drastically reduced when compared with that at present. It was noteworthy that moderately and highly suitable growth areas of wild E. ulmoides all disappeared, and junction between Shaanxi and Gansu and Taibai Mountain would be stable suitable growth area of wild E. ulmoides. [ Condusioa] The research could provide useful reference data for investigation, protection and sustainable development of the wild E. ulmoides resources.

Assessment of Habitat Suitability in the Upper Reaches of the Min River in China

HabRat richness influences and even determines biological diversity. Plant habitat suitability assessment can provide technical guidance and information support for ecological restoration. Thirteen factors in three categories of terrain, meteorology and soil were chosen to build a habitat suitability assessment index framework in the Upper Reaches of the Min River, based on the local natural environment and the actual influencing factors of vegetative growth. Combined with the Analytic Hierarchy Process （AHP） and entropy method, which were used to calculate weights of indexes, habitat suitability was studied by using a multi-objective linear weighting model and geographic information systems （GIS） spatial analysis techniques. The assessment results are as follows： Altitude, soil stability, aspect and slope have more important effects on plant habitat suitability in the Upper Reaches of the Min River, and their weights are o.311, 0.260, o.198 and o.125, respectively. Suitable and sub-suitable habitats cover 4431.8o km2 and 6171.12 km2, respectively; most of which are distributed along both sides of rivers and have higher suitability. Unsuitable habitats cover the largest area （6679.76 km2）, accounting for 29.83% of the whole area; and the worst unsuitable habitats are 5107.23 km2 （22.81%）; they account for more than half of the study area. These results indicate that the plant habitat in the Upper Reaches of the Min River is poor and ecological restoration is both urgent and difficult. Therefore, based on the principle of taking measures suitable to the habitat in ecological restoration projects, ecological and engineering measures should be combined to have better effects, while increasing the strength of ecological protection.

Predicting the potential geographic distribution of Bactrocera bryoniae and Bactrocera neohumeralis(Diptera: Tephritidae) in China using MaxEnt ecological niche modeling

Bactrocera bryoniae and Bactrocera neohumeralis are highly destructive and major biosecurity/quarantine pests of fruit and vegetable in the tropical and subtropical regions in the South Pacific and Australia.Although these pests have not established in China,precautions must be taken due to their highly destructive nature.Thus,we predicted the potential geographic distribution of B.bryoniae and B.neohumeralis across the world and in particular China by ecological niche modeling of the Maximum Entropy(Max Ent)model with the occurrence records of these two species.Bactrocera bryoniae and B.neohumeralis exhibit similar potential geographic distribution ranges across the world and in China,and each species was predicted to be able to distribute to over 20%of the globe.Globally,the potential geographic distribution ranges for these two fruit fly species included southern Asia,the central and the southeast coast of Africa,southern North America,northern and central South America,and Australia.While within China,most of the southern Yangtze River area was found suitable for these species.Notably,southern China was considered to have the highest risk of B.bryoniae and B.neohumeralis invasions.Our study identifies the regions at high risk for potential establishment of B.bryoniae and B.neohumeralis in the world and in particular China,and informs the development of inspection and biosecurity/quarantine measures to prevent and control their invasions.

Evolution of Potential Spatial Distribution Patterns of Carex Tussock Wetlands Under Climate Change Scenarios,Northeast China

Carex tussock plays an important role in supporting biodiversity and carbon sequestration of wetland ecosystems,while it is highly threatened by climate change and anthropogenic activities.Therefore,identifying the potential distribution patterns of Carex tussocks wetland is vital for their targeted conservation and restoration.The current and future(2050s and 2070s)potential habitats distribution of Carex tussocks in Northeast China were predicted using a Maximum Entropy(Maxent)model based on 68 current data of Carex tussock distributions and three groups of environmental variables(bioclimate,topography,soil properties).Results show that isothermality,seasonal precipitation variability and altitude are important factors that determine the distribution of Carex tussock.The high suitable habitat of Carex tussock is about 5.7×10^(4)km^(2) and mainly distributed in the Sanjiang Plain,Songnen Plain,Changbai Mountains and Da Hinggan Mountains.The area of stable habitats of Carex tussock is significantly higher than the lost and expanded habitats in the future climate scenarios,and the unsuitable habitats mainly occur in Da Hinggan Mountains,Xiao Hinggan Mountains and Changbai Mountains.Overall,Carex tussock wetlands at high altitude and high latitude are more sensitive to climate change,and more attention should be invested in high latitude and high altitude areas.

Species distribution modeling in regions of high need and limited data： waterfowl of China

Background: A number of conservation and societal issues require understanding how species are distributed on the landscape, yet ecologists are often faced with a lack of data to develop models at the resolution and extent desired, resulting in inefficient use of conservation resources.Such a situation presented itself in our attempt to develop waterfowl distribution models as part of a multi-disciplinary team targeting the control of the highly pathogenic H5N1 avian influenza virus in China.Methods: Faced with limited data, we built species distribution models using a habitat suitability approach for China's breeding and non-breeding(hereafter, wintering) waterfowl.An extensive review of the literature was used to determine model parameters for habitat modeling.Habitat relationships were implemented in GIS using land cover covariates.Wintering models were validated using waterfowl census data, while breeding models, though developed for many species, were only validated for the one species with sufficient telemetry data available.Results: We developed suitability models for 42 waterfowl species(30 breeding and 39 wintering) at 1 km resolution for the extent of China, along with cumulative and genus level species richness maps.Breeding season models showed highest waterfowl suitability in wetlands of the high-elevation west-central plateau and northeastern China.Wintering waterfowl suitability was highest in the lowland regions of southeastern China.Validation measures indicated strong performance in predicting species presence.Comparing our model outputs to China's protected areas indicated that breeding habitat was generally better covered than wintering habitat, and identified locations for which additional research and protection should be prioritized.Conclusions: These suitability models are the first available for many of China's waterfowl species, and have direct utility to conservation and habitat planning and prioritizing management of critically important areas, providing an example of how this approach may aid others faced with the challenge of addressing conservation issues with little data to inform decision making.

Predicting Ecological Distribution of the Toxic Dinoflagellate Alexandrium minutum in China Sea Using Ecological Niche Modeling

Alexandrium minutum from the China Sea produces a range of toxins and causes damage to the local ecosystems and aquaculture.This is essential to understand environmental factors affecting potential distribution.Potential distributions of A.minutum in the China Sea were predicted based on maximum entropy modeling,and dominant environmental variables were studied through analyses of variable contributions and response curves.The results showed that highly suitable areas were mainly located in the southwest of the Yellow Sea,the Laizhou Bay,and north of Haizhou Bay.The coast of the South China Sea was predicted as a low-suitability area,and the coast of the East China Sea as an unsuitable area.Mean temperature of the coldest month(T_min)had the largest drop in permutation importance but a low percent contribution.The probability of presence of A.minutum increased with increasing concentration of nitrate(NO3−)and annual mean temperature(T_ann)over a wide range of them.The response curves decreased with increasing concentration of phosphate(PO43−)and ratio of NO_(3)^(−)to PO_(4)^(3−)(N_P_ratio)when PO_(4)^(3)−is above 0.049μmolL^(-1) and N_P_ratio above 4,indicating that low values of PO_(4)^(3−) concentration and N_P_ratio favour the occurrence of A.minutum.As a predictor,the variance of annual temperature(T_Var)had the highest percent contribution and gains.PO_(4)^(3−) was predicted to have much more information than the other variables,and exhibited the second largest drop in permutation importance and percent contribution.The T_Var and PO_(4)^(3−) are the most important dominant predictor variables.

Eff ects of climate change on the potential habitat distribution of swimming crab Portunus trituberculatus under the species distribution model

Over the last decades,the species distribution model(SDM)has become an essential tool for studying the potential eff ects of climate change on species distribution.In this study,an ensemble SDM was developed to predict the changes in species distribution of swimming crab Portunus trituberculatus across diff erent seasons in the future(2050s and 2100s)under the climate scenarios of Representative Concentration Pathway(RCP)4.5 and RCP8.5.Results of the ensemble SDM indicate that the distribution of this species will move northward and exhibit evident seasonal variations.Among the four seasons,the suitable habitat for this species will be signifi cantly reduced in summer,with loss rates ranging from 45.23%(RCP4.5)to 88.26%(RCP.8.5)by the 2100s.The loss of habitat will mostly occur in the East China Sea and the southern part of the Yellow Sea,while a slight increase in habitat will occur in the northern part of the Bohai Sea.These fi ndings provide an information forecast for this species in the future.Such forecast will be helpful in improving fi shery management under climate change.

Potentially Suitable Area and Change Trends of Tulipa iliensis under Climate Change

Tulipa iliensis,as a wild plant resource,possesses high ornamental value and can provide abundant parental materials for tulip breeding.The objective of this research was to forecast the worldwide geographical spread of Tulipa iliensis by considering bioclimatic,soil,and topographic variables,the findings of this research can act as a benchmark for the conservation,management,and utilization of Tulipa iliensis as a wild plant resource.Research results indicate that all 12 models have an area under curve(AUC)of the receiver operating characteristic curve(ROC)values greater than 0.968 for the paleoclimatic,current,and future climate scenarios,this suggests an exceptionally high level of predictive accuracy for the models.The distribution of Tulipa iliensis is influenced by several key factors.These factors include the mean temperature of the driest quarter(Bio9),calcium carbonate content(T_CACO3),slope,precipitation of the driest month(Bio14),Basic saturation(T_BS),and precipitation of the coldest quarter(Bio19).During the three paleoclimate climate scenarios,the appropriate habitats for Tulipa iliensis showed a pattern of expansion-contraction expansion.Furthermore,the total suitable area accounted for 13.38%,12.28%,and 13.28%of the mainland area,respectively.According to the current climate scenario,the High-suitability area covers 61.78472×10^(4)km^(2),which accounts for 6.57%of the total suitable area,The Midsuitability area covers 190.0938×10^(4)km^(2),accounting for 20.2%of the total suitable area,this represents a decrease of 63.53%~67.13%compared to the suitable area of Tulipa iliensis under the paleoclimate scenario.Under the Shared Socioeconomic Pathways(SSP)scenarios,in 2050 and 2090,Tulipa iliensis is projected to experience a decrease in the High,Mid,and Low-suitability areas under the SSP126 climate scenario by 7.10%~12.96%,2.96%~4.27%and 4.80%~7.96%,respectively.According to the SSP245 scenario,the high suitability area experienced a slight expansion of 2.26%in 2050,but a reduction of 6.32%in 2090.In the SSP370 scenario,the High-suitability areas had a larger reduction rate of 11.24%in 2050,while the Mid-suitability and Low-suitability areas had smaller expansion rates of 0.36%and 4.86%,respectively.In 2090,the High-suitability area decreased by 4.84%,while the Mid and Low-suitability areas experienced significant expansions of 15.73%and 45.89%,respectively.According to the SSP585 scenario,in the future,the High,Mid,and Low-suitability areas are projected to increase by 5.09%~7.21%,7.57%~17.66%,and 12.30%~48.98%,respectively.The research offers enhanced theoretical direction for preserving Tulipa iliensis’genetic variety amidst evolving climatic scenarios.

Modeling the Past and Current Distribution and Habitat Suitability for Ablepharus grayanus and A. pannonicus(Sauria: Scincidae)

Study of the climate variability in the past and present, and correlating those with changes in the distribution range of species has attracted considerable research interest. The genus Ablepharus consists of 10 recognized species, of which A. bivittatus, A. grayanus and A. pannonicus are documented from Iran. In the present study, we modeled with MaxEnt the potential distribution areas and determined the suitable habitats in past （mid-Holocene [MH], and the Last Interglacial [LIG]） and their current distribution for two species of snake-eyed skinks （A. grayanus and A. pannonicus） separately. Models of the species indicated good fit by the average high area under the curve （AUC） values （A. grayanus = 0.929 4- 0.087 and A. pannonicus = 0.979 4- 0.007）. Precipitation of the driest quarter of the year, mean temperature of the coldest quarter of the year, and precipitation of the driest month variables made important contributions to A. grayanus. Two important climate variables contributed importantly to A. pannonicus; temperature seasonality, and mean temperature of the wettest quarter of the year, and one topographic variable, slope. We conclude that these variables form a natural barrier for species dispersal. The MH and the LGM models indicated a larger suitable area than the current distribution.

Evaluating the Importance of Environmental Variables on Spatial Distribution of Caspian cobra Naja oxiana(Eichwald, 1831) in Iran

Over recent years, the population of Caspian cobra Naja oxiana has declined in its distribution range in Iran due to habitat destruction and overhunting. Consequently, their small and isolated populations in fragmented landscapes are facing genetic and demographic threats. Evaluating the spatial distribution pattern of Naja oxiana, identifying core habitat patches and improving landscape connectivity among the patches have a significant role in the long-term survival of the species. This study predicts the spatial distribution map of the Caspian cobra considering the factors affecting the predictive power of the distribution models, including sampling bias in presence points, correct selection of background locations, and input model parameters. The sampling bias in presence points was removed using spatial filtering. Several models were run using 19 environmental variables that eventually led to the selection of the effective habitat variables and best MaxEnt distribution model. We also used an ensemble model(EM) of habitat suitability methods to predict the potential habitats of the species. Topographical roughness, shrublands, average annual precipitation, and sparse rangeland with a density of ≤ 20% had the most effect on the spatial distribution of Caspian cobra. The evaluation of models confirmed that the EM has more predictive performance than MaxEnt in predicting the distribution of Naja oxiana.

Study on the Spatial Distribution of Resource-based Urban Land Based on Suitability Evaluation——A Case Study of Datong City in Shanxi Province

[ Objective] The study aimed at analyzing the spatial distribution of urban land based on the suitability evaluation of construction land in a resource-based city. [Methed] Firstly, the suitability of construction land in the center of Datong City was assessed; afterwards, according to the urban scale and spatial expansion mode in target years in the General Land Use Planning for Datong City （2006 -2020）, the spatial layout of new- ly-increased urban land and flexible construction land was carried out to determine the development boundary of Datong City in 2020. [ Result] In the evaluation area of Datong City, the most suitable construction land had an area of only 66.18 hm2, accounting for 10.40% of total area of evalu- ation region; the area of more suitable construction land was 117.51 hm2 and make up 18.47% of total area; moderately suitable land covered an area of 149.49 hm2, which took up 23.49% of total area; the area of unsuitable construction land （89.31 hm2 ） only made up 14.04% of total area. In the newly-increased urban construction land, the area of the most suitable and more suitable land accounted for 73.58%, while there was no un- suitable land. Meanwhile, in flexible construction land, the area of the most suitable and more suitable land made up 66.85%. In a word, the spa- tial layout of urban land was reasonable in Datong City. [Conclusion] The research could provide theoretical references for the spatial expansion and layout of urban land.

Community Characteristics of Wild Fruit Forests Along Elevation Gradients and the Relationships Between the Wild Fruit Forests and Environments in the Keguqin Mountain Region ofⅠii

In this paper,the quantitative relationship between the wild fruit communities and direct environmental factors is discussed on the basis of detailed data on landscape scale habitats obtained through field vegetation investigation.The results from TWINSPAN and DCCA showed that:1) In the distribution sections of the wild fruit forest in the Keguqin Mountain region,the basic patterns characteristic of the different habitats are due to topographic factors,nutrients and moisture conditions;2) The elevation affected the most basic differentiation of plant communities in the study area,indicating that the elevation condition was the most important factor restricting the distribution of the wild fruit communities in the study area;3) The close relationship between the moisture content in the upper soil layer and the elevation reflected the influence of moisture conditions on both wild fruit and herb-layer communities;4) Nutrient differences not only indicated that the habitat conditions were different in themselves but also showed that the present nutrient conditions of the habitats were seriously affected by human activities.In summary,under complicated mountainous topographic conditions,the habitat conditions for the communities differed very significantly,and the combination of elevation,soil moisture content,total nitrogen,slope aspect,and pH value influenced and controlled the formation of community distribution patterns in the study area.

China's Sloping Land Conversion Program at the Beginning of 21st Century and Its Habitat Suitability in Typical Region of Loess Plateau

自1999年我国开始试行以"退耕还林"工程为主的生态退耕以来,到目前已历时十年。特别是进入21世纪,工程实施强度较大,因此从国家尺度上进行宏观生态退耕格局的分析对于评估生态退耕政策和确定未来政策导向具有重要意义。本研究以TM遥感监测的土地利用变化数据库为基础分析2000-2005年生态退耕的时空格局。在此基础上,以黄土高原典型地区陕西中北部为研究区,采用生态位适宜度评价模型探讨了生态退耕工程实施的合理性。研究结果表明:(1)2000-2005年间,生态退耕主要集中在中国中部地区,尤其是在黄河和长江的中上游地区,生态退耕面积与建设占用面积基本持平。在各生态类型区中,黄土高原土壤侵蚀区生态退耕面积最大,达到了1162.50km^2,主要用于还林;(2)整体看来,研究区内生态退耕的空间格局是合理的,即适宜性越差的耕地退耕比例越大。从退耕区域的适宜性水平来看,有77.35%的地区属于勉强适宜区,其中退为林地的面积为603.32km^2,退为草地的面积为528.94km^2。整个研究区内前者大于后者。然而,退耕地中仍有19.38%属于中度适宜区,原因可能来自于退耕指标分配等管理因素,另外,当地农民外出务工从而将中等适宜度的耕地退耕。结果表明,当前仍有大面积不适宜和勉强适宜的耕地存在,在未来工程实施过程区应该首先考虑该类地区。

阿根廷滑柔鱼(Illex argentinus)适宜栖息地模型比较及其在渔场预报中的应用

根据2003–2007年1–5月西南大西洋阿根廷滑柔鱼生产统计数据以及表温(SST)、海面高度(SSH)等海洋遥感数据,以作业次数为基础采用外包络法建立SST、SSH的适应性指数模型。分别采用算术平均法(AMM)和几何平均法(GMM)建立栖息地指数(HSI)模型,并对2003–2007年1–5月的HSI值与实际产量和作业次数作比较。研究结果显示,AMM和GMM均拟合较好,HSI>0.6时,AMM的产量和作业次数比例分别为86.75%和89.82%;GMM的产量和作业次数比例分别为84.30%和85.80%,AMM稍优于GMM。利用2008年1–5月的阿根廷滑柔鱼生产数据进行实证分析,结果显示,作业渔场主要分布在HIS>0.6的海域,其产量占总产量的64%以上,作业次数占总作业次数的68%以上;基于SST和SSH的AMM栖息地指数模型可用于阿根廷滑柔鱼中心渔场的实时动态预报,为该资源的高效开发提供科学依据。

基于MaxEnt模型分析不同气候变化情景下的黄心夜合(Michelia martinii)潜在地理分布

黄心夜合(Michelia martinii)是木兰科含笑属乔木,具有很高的观赏价值,是优良的香料和用材树种。然而其野生资源保存状况不容乐观,被1999颁布的《国家重点保护野生植物名录(第一批)》列为Ⅱ级珍稀濒危植物,现在其保护级别为近危(NT)。预测气候变化对分布范围的影响可为黄心夜合的野生资源保存与可持续利用提供科学基础和参考依据。利用ArcGIS 10.4与MaxEnt 3.4.1软件分析了黄心夜合在全国范围内的潜在地理分布,并与DIVA-GIS 7.5软件的Bioclim和Domain模型进行比较,选择了预测结果最佳模型MaxEnt,继而预测了21世纪50和70年代4种气候情景(RCP 2.6、RCP 4.5、RCP 6.0、RCP 8.5)下其适生区分布范围。结果表明,MaxEnt模型预测黄心夜合潜在生境分布的精度最高,受试者特征曲线(receiver operating characteristic,ROC)训练集的线下面积(area under ROC curve,AUC)为0.977;最干月降雨量、海拔、昼夜温差月均值、年均降雨量是影响黄心夜合分布的主要气候因子,其贡献率分别为43.8%、20.7%、15.2%、8.8%。现阶段黄心夜合的高、中、低适生区以贵州省为中心向四周扩散,适生区总面积共约5.7×10^(5)km^(2)。21世纪50和70年代其适生区分布基本格局不变,21世纪50年代除了RCP 8.5情景外,黄心夜合的低、中适生区以及适生区面积总和增加。21世纪70年代,黄心夜合的中、高适生区及总适生区面积均有所减少。未来全球气候变暖会造成黄心夜合的高适生区大幅缩减。未来大部分情景下,黄心夜合的分布质心均有向东北方迁移的趋势。黄心夜合保护的难点在于其适生区域之间相互孤立、相隔较远,加剧了其灭绝的可能。未来对于黄心夜合濒危资源的保护应结合地理分布的预测结果,从野生资源调查、野外回归的迁地保护、就地建立保护区、开展繁殖与栽培技术研究等方面入手。

Incorporating physiological knowledge into correlative species distribution models minimizes bias introduced by the choice of calibration area

Correlative species distribution models(SDMs)are important tools to estimate species’geographic distribution across space and time,but their reliability heavily relies on the availability and quality of occurrence data.Estimations can be biased when occurrences do not fully represent the environmental requirement of a species.We tested to what extent species’physiological knowledge might influence SDM estimations.Focusing on the Japanese sea cucumber Apostichopus japonicus within the coastal ocean of East Asia,we compiled a comprehensive dataset of occurrence records.We then explored the importance of incorporating physiological knowledge into SDMs by calibrating two types of correlative SDMs:a naïve model that solely depends on environmental correlates,and a physiologically informed model that further incorporates physiological information as priors.We further tested the models’sensitivity to calibration area choices by fitting them with different buffered areas around known presences.Compared with naïve models,the physiologically informed models successfully captured the negative influence of high temperature on A.japonicus and were less sensitive to the choice of calibration area.The naïve models resulted in more optimistic prediction of the changes of potential distributions under climate change(i.e.,larger range expansion and less contraction)than the physiologically informed models.Our findings highlight benefits from incorporating physiological information into correlative SDMs,namely mitigating the uncertainties associated with the choice of calibration area.Given these promising features,we encourage future SDM studies to consider species physi-ological information where available.

Habitat suitability modeling of amphibian species in southern and central China:environmental correlates and potential richness mapping

Successful wildlife management must take into account suitable habitat areas. Information on the correlation between distribution ranges and environmental conditions would, therefore, improve the efficacy of in-situ conservation of wildlife. In this contribution, correlations between environmental factors and the distribution of 51 amphibians in southern and central China were investigated. Ecological niche factor analysis （ENFA） at a spatial resolution of 1°latitudexllongitude identified a mixture of climatic and habitat factors as important predictors of the occurrence of individual species. The aims of the present work were （i） to evaluate potential distributions of amphibians based on the suitability of areas; （ii） to identify the major environmental descriptors upon which they depend; and （iii） to identify areas of potential high richness that have been overlooked in available inventories. Most of the predicted species ranges of species covered the majority of southern and central China. Six richness hotspots were predicted, of which four have been described previously, but two overlooked （SE Fujian and SE Qinghai）. The prediction model was considered to be relatively accurate and it is recommended that these two new potential hotspots should be subjected to further evaluation and sampling efforts. Amphibians have high ecological preference for high humidity and precipitation, and low annual frost days. ENFA is a useful tool in wildlife conservation assessment because it is able to identify potential hotspots where studies on the correlations between environmental descriptors and the occurrence of particular species could be focused.