基于MAXENT模型的贺兰山西坡啮齿动物生境适宜性评价

贺兰山因其拥有独特的植物垂直分布带而十分适宜啮齿动物生存,但自保护区生态恢复以来并未见有研究评价啮齿动物在贺兰山的生境适宜性,使得其分布现状未知。使用GIS技术和MAXENT模型对内蒙古贺兰山国家级自然保护区6种主要啮齿动物进行生境适宜性状况评价及预测,探究啮齿动物在贺兰山的分布现状。结果表明：影响6种啮齿动物的主要环境因子为海拔、坡度和距矿区距离,海拔越高、坡度越大及距矿区距离越近均使啮齿动物生存适宜性降低;两两鼠种生境适宜面积叠加发现,大林姬鼠和阿拉善黄鼠适宜生境重叠面积最大(261.37 km~2),短尾仓鼠和子午沙鼠的适宜生境重叠面积最小(19.00 km~2);6种主要鼠种均适宜的生境面积交集仅有17.14 km~2,占贺兰山总面积的0.47%,6种主要鼠种均不适宜的生境面积有2985.23 km~2,占贺兰山总面积的81.21%。研究表明,啮齿动物栖息地距矿区距离仍是影响其适宜生境的重要因素之一,建议相关部门加强对废弃矿区采取措施,改善保护区啮齿动物生境质量。     

东方白鹳在山东省适宜栖息地的分布预测

东方白鹳(Ciconia boyciana)隶属鹳形目(Ciconiiformes)鹳科(Cioniidae)鹳属(Ciconia),被IUCN濒危物种红色名录列为濒危(EN),主要繁殖于俄罗斯远东地区与中国东北三江平原,在长江中下游鄱阳湖等沿海内陆湖泊越冬。山东省从2003年开始有东方白鹳繁殖记录,黄河三角洲为该物种在山东省的主要繁殖地。以在黄河三角洲自然保护区收集到的位点数据、物种分布数据库(GBIF)提取的位点数据和山东省环境气候因子为基础数据,基于最大熵(Maxent)模型和地理信息系统(ArcGIS)技术平台,预测东方白鹳在山东省的潜在适生区。结果表明在该物种在黄河三角洲及附近地区存在较集中的高适宜区,庙岛群岛和微山湖地区存在少量高适宜区,高适宜区总面积为1359.27km²;北至河北边界,南至微山县,沿黄河支流至西到达聊城市、菏泽市,存在1893.82km²较适宜区和3955.63km²低适宜区。潜在适宜生境总和为7208.72km²,占比为研究区域的0.89%。新出现的较为集中的较适宜...     

Habitat suitability of Gymnocladus assamicus - A critically endangered plant of Arunachal Pradesh,India using machine learning and statistical modeling

The present study sought to identify the potential distribution range of critically endangered Gymnocladus assamicus in Arunachal Pradesh based on published data and field collection. We used the Maxent model to estimate the range of distribution and the result was then compared with three other models, i.e., the Generalized Linear Model (GLM), the Bioclim and the Random Forest model to assess the species' habitat suitability. A total of 23 different environmental variables were used, including bioclimatic ones, monthly minimum and maximum temperature, monthly precipitation and elevation data. The Maxent output listed 12 variables explaining 99.9% variation in the model. In comparison, Maxent showed the maximum region under habitat suitability criteria (1884.48 km²), followed by Random Forest (70.73 km²) and Bioclim (11.62 km²) model. Except for the Maxent model, suitable habitats predicted by other models are highly restricted within and across the study species' current distribution range. The average model prediction shows an expanded distribution range for the species up to Tawang which is the closest district of currently known distribution of the species in the state. Thus, the present study recognizes the importance of the geographic range of G. assamicus, a critically endangered species with very limited spatial distribution range and also provides some specific details to explore possible habitats for the species in new areas of potential occurrence in Arunachal Pradesh, India.     

同域分布中华鬣羚与中华斑羚时空生态位特征

为了解同域分布有蹄类在环境复杂的山地森林生境中以何种方式维持种间关系以实现稳定共存,基于物种分布模型与日活动模式分析了四川省岷山、邛崃、大相岭、小相岭和凉山五大山系同域分布中华鬣羚(Capricornis milneedwardsii)与中华斑羚(Naemorhedus griseus)的时空生态位特征。结果显示:(1)在四川省五大山系,中华鬣羚的适宜栖息地面积为28006.07 km²,占研究区总面积的26.18%,其中高适宜栖息地面积为10015.90 km²,中华斑羚的适宜栖息地面积为21073.32 km²,占研究区总面积的19.71%,其中高适宜栖息地面积为8396.22 km²;(2)中华鬣羚与中华斑羚在生境因子选择上相似性高、栖息地重叠面积大,其空间生态位重叠度指数D=0.776,I=0.949,其适宜栖息地的主要重叠区域位于岷山和邛崃山系;(3)中华鬣羚与中华斑羚的日活动节律重叠指数为0.812;(4)中华鬣羚与中华斑羚属于同域分布的资源利用型竞争物种,中华鬣羚的存在会显著影响中华斑羚的日活动节律(P=0.016);二者同域分布时都会增加其昼间活动强度,并增加活动高峰期的强度及持续时间。本研究初步分析了中华鬣羚与中华斑羚的时空生态位特征,揭示了二者在空间、时间生态位上种群共存及种间竞争的耦合关系。研究有利于深入理解同域分布动物时空生态位特征、近缘物种的共存机制及种间竞争关系,为有蹄类等珍稀野生动物种群及栖息地的保护提供科学参考。     

张广才岭南部东北虎猎物种群冬季营养容纳量研究

猎物匮乏是影响东北虎（Panthera tigris altaica）种群恢复的关键因素之一。容纳量研究是开展东北虎猎物恢复工作的必要前提。通过Maxent模型、聚类分析和训练随机树分类等方法,结合调查数据,预测了吉林省张广才岭南部黄泥河林业局东北虎主要猎物的适宜栖息地空间分布,解译了植被类型,在此基础上基于不同植被类型动物可采食部分代谢能、不同生境等级食物可利用率、马鹿（Cervus elaphus）和狍（Capreolus capreolus）生境等级重叠情况以及动物冬季能量需求,分析了东北虎猎物的冬季营养容纳量。结果表明：黄泥河林业局狍、野猪（Sus scrofa）和马鹿的适宜栖息地分别占研究区域总面积的52.8%、40.7%和25.4%;从猎物获取能量来看,以山杨（Populus davidiana）、桦树（Betula）、核桃楸（Juglans mandshurica）为主的植被类型是马鹿、狍可获得能量较多的生境,以蒙古栎（Quercus mongolica）、核桃楸为主的植被类型是野猪可获得能量较多的生境。东北虎猎物种群的综合冬季营养容纳量为574只马鹿（0.29只/km²）,7016只狍（3.54只/km²）,4785只野猪（2.38只/km²）。     

Habitat assessment of Marco Polo sheep (Ovis ammon polii) in Eastern Tajikistan: Modeling the effects of climate change

Identifying the factors predicting the high‐elevation suitable habitats of Central Asian argali wild sheep and how these suitable habitats are affected by the changing climate regimes could help address conservation and management efforts and identify future critical habitat for the species in eastern Tajikistan. This study used environmental niche models (ENMs) to map and compare potential present and future distributions of suitable environmental conditions for Marco Polo argali. Argali occurrence points were collected during field surveys conducted from 2009 to 2016. Our models showed that terrain ruggedness and annual mean temperature had strong correlations on argali distribution. We then used two greenhouse gas concentration trajectories (RCP 4.5 and RCP 8.5) for two future time periods (2050 and 2070) to model the impacts of climate change on Marco Polo argali habitat. Results indicated a decline of suitable habitat with majority of losses observed at lower elevations (3,300–4,300 m). Models that considered all variables (climatic and nonclimatic) predicted losses of present suitable areas of 60.6% (6,928 km²) and 63.2% (7,219 km²) by 2050 and 2070, respectively. Results also showed averaged habitat gains of 46.2% (6,106 km²) at much higher elevations (4,500–6,900 m) and that elevational shifts of habitat use could occur in the future. Our results could provide information for conservation planning for this near threatened species in the region.     

Potential geographical distribution of Actinidia spp. and its predominant indices under climate change

Kiwifruit (Actinidia ssp.) is an economically and nutritionally important fruit crop with a remarkably high vitamin C content. Shaanxi Province, China, has the world's largest production base for kiwifruit; hence, it is necessary to accurately assess the potential geographic distribution of kiwifruit in this area for planting planning and government management. To perform this analysis, we selected three categories of environmental indices (climate, soil, and topographical) for a total of 18 ecological suitability assessment indices. Based on fuzzy mathematic theory, we built 18 membership functions to show the quantitative relationship between kiwifruit yield and these 18 assessment indices. Furthermore, an assessment model of kiwifruit suitability for cultivation was constructed using a combination of the weighted average method and GIS spatial analysis of the present land-use map of Shaanxi. The results show that 5860.1 km² (14.0%) of arable land and orchard can be demarcated as highly suitable for kiwifruit cultivation, 7868.9 km² (18.7%) suitable for rapeseed cultivation; 11,392.1 km² (27.1%) marginally suitable for rapeseed cultivation; and 16,892.5 km² (40.2%) as unsuitable for kiwifruit cultivation in this province. We provide a useful assessment system for ecological zoning of kiwifruit suitability and identify the highly suitable planting area of kiwifruit in Shaanxi Province. south Shannan and south Guanzhong. These results provide a reference tool for distribution rationalization and resource optimization of kiwifruit-planting areas.     

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

Identifying habitat suitability and potential corridors are important tools for biodiversity conservation in the face of climate change. We modeled habitat suitability and simulated possible corridors for movement and gene flow among the Asiatic black bear (Ursus thibetanus) population in the Northern Highlands of Pakistan (NHP). Results indicated that the areas of 13,923 km² and 21,931 km² suitable for the Asiatic black bear under current and future scenarios respectively. Under the future scenario, we found an area of 12,657 km² (57.21%) as increase in suitable habitat (ISH_f) and 4649 km² (33.39%) area as a decrease in current suitable habitat (DSH_c). Our model predicted that about >65% (9274 km²) of the current suitable habitat as a climate refugia which is projected from the center to southeast east and northwest of the NHP primarily in the Khyber Pakhtunkhwa (KPK) and Pakistan Administered Kashmir (PAK). The attitudinal range of refugia was projected from 688 m to 4483 m with >56% at the elevations between 2001 m to 3000 m. A very small portion of suitable habitats (current suitable habitat = 2.75%, future suitable habitat = 5.11%) were projected under the protected areas. Maps connecting suitable habitats identified different regions delineated as important for the dispersal of Asiatic black bears, which mainly distributed in the PAK and KPK. Our results help informs conservation strategies and management plans for mitigating the impacts of climate change on Asiatic black bears in the NHP.     

Population densities and habitat use of the golden jackal (Canis aureus) in farmlands across the Balkan Peninsula

The main objective of this study was to analyze the habitat use and population densities of the golden jackal in four countries across lowland regions of the Balkan Peninsula, known as the core area of the species' distribution in Europe. Using indirect (acoustic) method for detecting territorial golden jackals, we surveyed jackal presence and densities on 331 monitoring sites in four countries, covering area an of 4,296 km² in total during April and May 2007–2012. We used GIS to assess landscape and environmental characteristics in a 2-km circular buffer (12.6 km²) around calling stations. Average population density of golden jackals in the study areas ranged between 0.6 and 1.1 territorial groups/10 km² (mean ± SE, 0.6?±?0.06 groups/10 km²), with several high-density areas with up to 4.8 territorial groups/10 km². Analysis of habitat use showed that for both jackal occurrence and number of jackal groups, the only significant parameter was the interaction between country and intensity of agriculture, indicating that jackals adapt their habitat selection patterns in relation to the habitat availability. We observed that selection of the more suitable habitats (shrub–herbaceous vegetation/heterogeneous agricultural vegetation) increased with lower proportion of these habitat types in the study area. Our study confirms high habitat plasticity of the golden jackal and offers explanation for its recent range expansion, which might be connected with the land use changes during the last decades in the Balkan Peninsula.     

气候变化对丹顶鹤秋季迁徙路线潜在生境适宜性的影响

目前全球变暖趋势的加剧对丹顶鹤等大型濒危水禽的栖息地造成了严重的威胁。由于监测方法和技术手段的限制,丹顶鹤在迁徙路线上潜在生境的分布范围尚不清楚,气候变化对丹顶鹤迁徙路线生境适宜性的影响机理有待进一步研究。基于138个丹顶鹤样本分布信息和19种环境变量数据,利用 BIOMOD2 软件包构建了丹顶鹤潜在生境评价的组合模型,对丹顶鹤在亚洲东部秋季迁徙路线上的生境适宜性进行数值模拟,并预测SSP1.2-6气候背景下2021-2040年、2041-2060年、2061-2080年、2081-2100年四个不同阶段的丹顶鹤潜在生境范围的变化趋势。研究结果表明:与单模型的模拟结果相比,集成9种单模型的BIOMOD2组合模型预测精度更高。集成模型的重要性分析表明,气温日较差是丹顶鹤生境适宜性变化的最重要的影响因子。受气候变化的影响2021-2040年、2041-2060年、2061-2080年、2081-2100年丹顶鹤潜在生境的面积将分别减少到2.60×10⁵km²、2.58×10⁵km²、2.75×10⁵km²、2.56×10⁵km²,迁徙路线上胶东半岛和环渤海地区适栖生境面积减少的最为显著。本研究对于迁徙路线上珍稀水禽潜在适宜生境的模拟及全球变化背景下珍稀水禽栖息地的保育和修复具有重要意义。     

Migrant shorebird use of Akimiski Island, Nunavut: a sub-arctic staging site

Determining the importance of stopover and staging areas to migrating shorebirds (Aves: Charadriiformes) is essential if such habitats are to be successfully protected. Migration chronology, species composition, length of stay, body condition, and estimated total abundance of shorebirds during spring and fall migratory periods of 2008 and 2009 were documented on Akimiski Island, Nunavut, Canada. Fourteen shorebird species were observed during spring point counts and 18 during fall. Semipalmated (Calidris pusilla) and White-rumped (C. fuscicollis) Sandpipers comprised about 80?% of all individuals observed. A greater number of species and individuals were observed during fall than spring in both years. Radio-transmitters attached to juvenile Semipalmated and Least (C. minutilla) Sandpipers indicated highly variable lengths of stay ranging up to 26?days in both species (Semipalmated Sandpiper averaged 6.5?±?2.67?days, n?=?12; Least Sandpipers averaged 7.25?±?3.79?days, n?=?8). In 2009, Semipalmated Sandpipers captured and weighed later in the season were significantly heavier than those captured earlier suggesting that this species is refueling while on Akimiski Island. A fall migration seasonal density of 5,267 (2,193–8,341) shorebirds/km² was estimated given a residence probability (i.e., the probability of an individual being present in consecutive counts) of 0.906?±?0.181. Assuming similar habitat value and shorebird density, an extrapolation of the seasonal plot density of 5,267 birds/km² to the total 192?km² mudflat habitat on Akimiski Island yields an estimate of 1,011,264 (421,098–1,601,429) shorebirds during fall migration, making Akimiski Island of Hemispheric importance as a staging site for migrant arctic-breeding shorebirds.     

松嫩平原苍鹭秋季栖息地选择及适宜性分布

苍鹭（Ardea cinerea）是松嫩平原湿地的常见鸟种,松嫩平原也是苍鹭重要的栖息地。为了了解苍鹭潜在栖息地的适宜性分布,利用GPS/GSM卫星跟踪技术,结合遥感影像和地理信息系统,应用Maxent模型对松嫩平原苍鹭秋季潜在的栖息地进行了评价,并对其适宜性分布进行了分析。结果显示：水源距离和绿度指数是影响松嫩平原苍鹭秋季栖息地适宜性的重要环境变量;松嫩平原内苍鹭适宜栖息地面积为2761.06 km²（占研究区域的1.24%）,主要分布在大庆（756.86 km²,占适宜栖息地面积的27.41%）、白城（537.14 km²,占适宜栖息地面积的19.45%）、齐齐哈尔（439.43 km²,占适宜栖息地面积的15.92%）等地市行政区,以大庆市杜尔伯特蒙古族自治县（429.90 km²,占适宜栖息地面积的15.57%）、白城市镇赉县（334.92 km²,占适宜栖息地面积的12.13%）、大庆市肇源县（185.54 km²,占适宜栖息地面积的6.72%）等县级行政区为主;其中,15.79%的适宜栖息地依次受到莫莫格保护区（10.34%）、扎龙保护区（3.47%）、向海保护区（0.67%）、查干湖保护区（0.54%）、大布苏保护区（0.41%）、乌裕尔河保护区（0.36%）等国家级自然保护区的保护。建议对未受到保护的零星小面积栖息地给与更多关注。     

Potential influence of tubicolous worms on the bottom roughness length z0 in the south-western Baltic Sea

The influence of three different species of tubicolous worms (Pygospio elegans, Polydora ciliata and Lagis koreni) on the hydrodynamic bottom roughness length (z₀) was analysed in this study. Flume experiments and geospatial methods were combined to determine the potential interactions between worm tubes and the near-bed flow regime and the resulting effects on sediment transport in the south-western Baltic Sea. The three selected species are common in the area of interest (3539 km²). Their species-specific population densities were taken from existing macrozoobenthos datasets and transferred into a Geographic Information System (GIS). In analogy to the sediment roughness length, the hydrodynamic roughness lengths generated by the tubicolous worms were calculated and corresponding sediment transport values, derived from flume experiments with artificial tube lawns, were geospatially analysed using GIS. In order to show the direct influence of worm tubes on the surrounding sediment surface flume experiments were conducted at two given current velocities of 20 cm s^− 1 for sediment displacement effects and 5 cm s^− 1 for deposition effects. The roughness length was shown to increase by a factor of 2 to 30 in the presence of biogenic structures such as the worm tubes. The near-bed hydrodynamic conditions are significantly influenced at low roughness densities through independent or isolated flow conditions at 0.7 to 1.9% and at high roughness densities between 4.2 and 7.5%, resulting in unaffected sediment surfaces through “skimming flow”, as well. The GIS analysis revealed that this effect occurs over 4% (137 km²) of the area of investigation, whereas sediment displacement at roughness densities between 0.7 and 1.9% due to increased turbulence is the predominant effect over 33% (present on 1172 km²) of the area of investigation. These findings reveal the important influence of species-generated microtopography on sediment transport processes.     

The impact of climate change on the distribution of rare and endangered tree Firmiana kwangsiensis using the Maxent modeling

The upsurge in anthropogenic climate change has accelerated the habitat loss and fragmentation of wild animals and plants. The rare and endangered plants are important biodiversity elements. However, the lack of comprehensive and reliable information on the spatial distribution of these organisms has hampered holistic and efficient conservation management measures. We explored the consequences of climate change on the geographical distribution of Firmiana kwangsiensis (Malvaceae), an endangered species, to provide a reference for conservation, introduction, and cultivation of this species in new ecological zones. Modeling of the potential distribution of F. kwangsiensis under the current and two future climate scenarios in maximum entropy was performed based on 30 occurrence records and 27 environmental variables of the plant. We found that precipitation‐associated and temperature‐associated variables limited the potentially suitable habitats for F. kwangsiensis. Our model predicted 259,504 km² of F. kwangsiensis habitat based on 25 percentile thresholds. However, the high suitable habitat for F. kwangsiensis is only about 41,027 km². F. kwangsiensis is most distributed in Guangxi''s protected areas. However, the existing reserves are only 2.7% of the total suitable habitat and 4.2% of the high suitable habitat for the plant, lower than the average protection area in Guangxi (7.2%). This means the current protected areas network is insufficient, underlining the need for alternative conservation mechanisms to protect the plant habitat. Our findings will help identify additional F. kwangsiensis localities and potential habitats and inform the development and implementation of conservation, management, and cultivation practices of such rare tree species.     

Highest densities of mountain hares (Lepus timidus) associated with ecologically restored bog but not grouse moorland management

Over the last 20 years, ecological restoration of degraded habitats has become common in conservation practice. Mountain hares (Lepus timidus scoticus) were surveyed during 2017–2021 using 830 km of line transects in the Peak District National Park, England. Historically degraded bog areas were previously reported having low hare numbers. Following bog restoration, we found hare densities of 32.6 individuals km⁻², notably higher than neighboring degraded (unrestored) bog with 24.4 hares km⁻². Hare density on restored peatland was 2.7 times higher than on bogs managed for grouse shooting at 12.2 hares km⁻² and 3.3 times higher than on heather moorland managed for grouse shooting at 10.0 hares km⁻². Yearly estimates varied most on habitats managed for grouse, perhaps indicative of the impact of habitat management, for example, heather burning and/or possible hare culling to control potential tick‐borne louping ill virus in gamebirds. Acid grassland used for sheep farming had a similar density to grouse moorland at 11.8 hares km⁻². Unmanaged dwarf shrub heath had the lowest density at 4.8 hares km⁻². Hare populations are characterized by significant yearly fluctuations, those in the study area increasing by 60% between 2017 and 2018 before declining by ca. 15% by 2020 and remaining stable to 2021. During an earlier survey in 2002, total abundance throughout the Peak District National Park was estimated at 3361 (95% CI: 2431–4612) hares. The present study estimated 3562 (2291–5624) hares suggesting a stable population over the last two decades despite fluctuations likely influenced by weather and anthropogenic factors. Mountain hares in the Peak District favored bog habitats and were associated with restored peatland habitat. Wildlife management should be cognizant of hare density variation between habitats, which may have implications for local extinction risk.     

Isolation from forest habitats reduces chances of the presence of <Emphasis Type="Italic">Osmoderma eremita</Emphasis> sensu lato (Coleoptera,Scarabaeidae) in rural avenues

Decline and fragmentation of natural habitats, such as old-growth forests, reduces their availability in the landscape. The solution to this problem for many forest-dwelling species, may be colonization of alternative habitats, such as parks, orchards or rural avenues, located in the highly fragmented agricultural landscape. Our main objective was to determine the effect of both habitat quality parameters and isolation from potential forest habitats, as primary habitats, on the occurrence of the hermit beetle (Osmoderma) in rural avenues in south-western Poland. The study was based on the results of an inventory of the species in 201 rural avenues within an area of approx. 30,000 km². Occurrence of the hermit beetle in such alternative habitats was affected by both habitat quality parameters and connectivity with suitable forest habitats. The species occurrence in an avenue was significantly positively affected by mean tree diameter and diversity of tree species, but probability of occurrence decreased as isolation of avenue from the deciduous forest increased. Moreover, in the study area the hermit beetle seemed to avoid alleys with a large proportion of Acer platanoides, Fraxinus excelsior and Populus spp. Spatially isolated roadside avenues have limited value in the preservation of the hermit beetle in the long term conservation management of the species. Conservation plans in such habitats should therefore take into account surrounding suitable habitats.     

Dispersal of the alien raccoon dog Nyctereutes procyonoides in Southern Brandenburg, Germany

The raccoon dog Nyctereutes procyonoides, an East Asian canid species, was introduced into the European part of the former USSR since 1928. Within 50 years (1935–1984), it colonised a territory of 1.4 million km² in Europe. A telemetry study took place in Southern Brandenburg in a 60 km² sized study area with a typical mosaic structured East German agricultural landscape. For catching raccoon dogs, 20 trap boxes were set there in an area of 46 km², and between February 2001 and July 2004, 15 (5 males, 10 females) adult and 46 (25 males, 21 females) juvenile raccoon dogs were eartagged and adults additionally fitted with radio collars (Biotrack, 150–151 MHz). Data on dispersal behaviour was collected by the relocation points of 11 juveniles (6 males, 5 females). Four juvenile males dispersed even more than 40 km from their trapping places. Additionally, dispersal of two adult males could be documented. This behaviour probably indicates that the German raccoon dog population still is in a process of colonising. This canid’s ability for colonising spacious and distant areas during comparative short periods of time and its preference for habitats with richness of water possibly make this species to be an important vector of fox tapeworm Echinococcus multilocularis—a very dangerous zoonosis.     

Predicting current and future distributions of Mentha pulegium L. in Tunisia under climate change conditions,using the MaxEnt model

Climate change and human activities have caused the degeneration of the natural habitats of medicinal plants. Mentha pulegium L. is one of the most common medicinal plants in Tunisia that features high economic and ecological values. Predicting species' suitable habitats, through modeling, has evolved as a useful tool for the assessment of resource conservation to protect medicinal plants. Herein, we used MaxEnt model to predict current and future distributions of M. pulegium under two representative concentration pathways (RCP2.6 and RCP8.5) for the years 2050 and 2070. MaxEnt modeling was in the “Excellent” category since all the AUCs were above 0.9. Results showed that high and moderate suitable habitats for the current distribution of M. pulegium encompassed ca. 9929 km² and 16,423 km², respectively. These areas are mainly located in North Tunisia. Precipitation of the coldest quarter (Bio19) was identified as the most critical factor shaping M. pulegium distribution. Compared to the current distribution, the highly and moderately suitable areas for M. pulegium under the two RCPs (RCP2.6 and RCP8.5) would decrease in the 2050s and 2070s. The model projected a shift of the suitable area from Northeastward to Center-eastward. These results may provide a useful tool for developing adaptive management strategies to enhance M. pulegium protection and sustainable utilization in the context of global climate change.     

Response of native ungulates to drought in semi‐arid Kenyan rangeland

The distribution and abundance of native ungulates were measured on commercially managed, semi‐arid rangeland in central Kenya over a 3‐year period that encompassed severe drought and above‐average rainfall. Native ungulate biomass density averaged 5282 kg km^?2 over the study and was dominated by elephant (Loxodonta africana), impala (Aepyceros melampus) and dik‐dik (Madoqua kirkii). Biomass density of domestic cattle (Bos taurus) averaged 2280 kg km^?2 during the study. Responses of native ungulates to severe drought were variable. Impala densities were similar to or greater than densities for similar habitat in protected areas, and varied from 12 to 16 km^?2 during and following the drought to 24–29 km^?2 following above‐average rainfall. Dik‐dik densities were also greater than densities reported for protected areas and were surprisingly stable throughout the study despite the wide annual fluctuations in rainfall. Elephant migrated out of the region during drought but were present at high densities (2.9–5.2 km^?2) during wet seasons, consistent with telemetry studies emphasizing the importance of Acacia bushland habitat on commercial rangelands for the migratory portion of the Laikipia–Samburu elephant population. Results show that substantial densities of native browsing and mixed‐feeding ungulates can occur on rangeland managed for commercial beef production and suggest that the capacity for ungulates to move over large spatial scales (>100 km²) and to shift distributions in response to locally variable thunderstorms may be important for sustaining these populations.     

The Mangrove Nursery Paradigm Revisited: Otolith Stable Isotopes Support Nursery-to-Reef Movements by Indo-Pacific Fishes

Mangroves and seagrass beds have long been perceived as important nurseries for many fish species. While there is growing evidence from the Western Atlantic that mangrove habitats are intricately connected to coral reefs through ontogenetic fish migrations, there is an ongoing debate of the value of these coastal ecosystems in the Indo-Pacific. The present study used natural tags, viz. otolith stable carbon and oxygen isotopes, to investigate for the first time the degree to which multiple tropical juvenile habitats subsidize coral reef fish populations in the Indo Pacific (Tanzania). Otoliths of three reef fish species (Lethrinus harak, L. lentjan and Lutjanus fulviflamma) were collected in mangrove, seagrass and coral reef habitats and analyzed for stable isotope ratios in the juvenile and adult otolith zones. δ¹³C signatures were significantly depleted in the juvenile compared to the adult zones, indicative of different habitat use through ontogeny. Maximum likelihood analysis identified that 82% of adult reef L. harak had resided in either mangrove (29%) or seagrass (53%) or reef (18%) habitats as juveniles. Of adult L. fulviflamma caught from offshore reefs, 99% had passed through mangroves habitats as juveniles. In contrast, L. lentjan adults originated predominantly from coral reefs (65–72%) as opposed to inshore vegetated habitats (28–35%). This study presents conclusive evidence for a nursery role of Indo-Pacific mangrove habitats for reef fish populations. It shows that intertidal habitats that are only temporarily available can form an important juvenile habitat for some species, and that reef fish populations are often replenished by multiple coastal habitats. Maintaining connectivity between inshore vegetated habitats and coral reefs, and conserving habitat mosaics rather than single nursery habitats, is a major priority for the sustainability of various Indo Pacific fish populations.