Niche Conservatism and Future Changes in the Potential Area Coverage of Arundina graminifolia,an Invasive Orchid Species from Southeast Asia

The Asian orchid, Arundina graminifolia, has been introduced to many locations over the last 50 yr, predominantly in South and Central America. A list of localities of A. graminifolia was compiled and used to model potential climatic niches based on the maximum entropy method. The differences are presented between niches occupied by native and invasive populations of A. graminifolia, and possible changes in the potential range of the species are discussed on the basis of various climate change scenarios. The coverage of habitats suitable for A. graminifolia will be reduced under future climate changes scenarios. The created niche distribution models indicated a more significant reduction in the potential ecological niches of the studied species in its invasive range. Nevertheless, areas with potentially suitable bioclimatic conditions for A. graminifolia should be monitored to prevent future uncontrolled invasion of the orchid into new habitats and to study its impact on the local ecosystems, as vast areas of its potential niche in the Americas are still unoccupied.     

Niche Conservatism and the Future Potential Range of Epipactis helleborine (Orchidaceae)

The aim of the present study was to evaluate the current distribution of suitable niches for the invasive orchid species, Epipactis helleborine, and to estimate the possibility of its further expansion. Moreover, niche modeling tools were used to explain its rapid expansion in North America and to test the niche conservatism of the species. The maximum entropy method was used to create models of the suitable niche distribution. A database of E. helleborine localities was prepared based on the examination of herbarium specimens, information from electronic databases as well as data gathered during field works. The differences between the niches occupied by native and invasive populations were evaluated using the niche overlap and niche identity test indexes. Moreover, the coverage of the most suitable habitats for the species was measured for three future scenarios as well as for the present time model. Populations of E. helleborine occupy North American west coast habitats very similar to those preferred by native, Eurasian populations, while the expansion in the east coast is related to the niche shift. The created models of suitable niche distribution indicate that the species does not realize its potential niche in the native range. The total surface of the habitats potentially available for E. helleborine will decrease in all climate change scenarios created for 2080.     

High invasion potential of Hydrilla verticillata in the Americas predicted using ecological niche modeling combined with genetic data

Ecological niche modeling is an effective tool to characterize the spatial distribution of suitable areas for species, and it is especially useful for predicting the potential distribution of invasive species. The widespread submerged plant Hydrilla verticillata (hydrilla) has an obvious phylogeographical pattern: Four genetic lineages occupy distinct regions in native range, and only one lineage invades the Americas. Here, we aimed to evaluate climatic niche conservatism of hydrilla in North America at the intraspecific level and explore its invasion potential in the Americas by comparing climatic niches in a phylogenetic context. Niche shift was found in the invasion process of hydrilla in North America, which is probably mainly attributed to high levels of somatic mutation. Dramatic changes in range expansion in the Americas were predicted in the situation of all four genetic lineages invading the Americas or future climatic changes, especially in South America; this suggests that there is a high invasion potential of hydrilla in the Americas. Our findings provide useful information for the management of hydrilla in the Americas and give an example of exploring intraspecific climatic niche to better understand species invasion.     

Towards the top: niche expansion of Taraxacum officinale and Ulex europaeus in mountain regions of South America

In the current context of ongoing global change, the understanding of how the niches of invasive species may change between different geographical areas or time periods is extremely important for the early detection and control of future invasions. We evaluated the effect of climate and non‐climate variables and the sensitivity to various spatial resolutions (i.e. 1 and 20 km) on niche changes during the invasion of Taraxacum officinale and Ulex europaeus in South America. We estimated niche changes using a combination of principal components analyses (PCA) and reciprocal Ecological Niche Modelling (rENM). We further investigated future invasion dynamics under a severe warming scenario for 2050 to unravel the role of niche shifts in the future potential distribution of the species. We observed a clear niche expansion for both species in South America towards higher temperature, precipitation and radiation relative to their native ranges. In contrast, the set of environmental conditions only occupied in the native ranges (i.e. niche unfilling) were less relevant. The magnitude of the niche shifts did not depend on the resolution of the variables. Models calibrated with occurrences from native range predicted large suitable areas in South America (outside of the Andes range) where T. officinale and U. europaeus are currently absent. Additionally, both species could increase their potential distributions by 2050, mostly in the southern part of the continent. In addition, the niche unfilling suggests high potential to invade additional regions in the future, which is extremely relevant considering the current impact of these species in the Southern Hemisphere. These findings confirm that invasive species can occupy new niches that are not predictable from knowledge based only on climate variables or information from the native range.     

Redistribution of the lizardfish Harpadon nehereus in coastal waters of China due to climate change

Climate change has the potential to greatly alter species distributions and threatens biodiversity in marine ecosystems. Mapping changes in species distribution patterns under climate change will help facilitate management strategies to maintain ecosystem structure and function. The lizardfish Harpadon nehereus is an aggressive predator that has experienced rapid population growth along the coast of China in recent decades, compressing the ecological niches of other marine species and disrupting food webs. If this species’ range is shifting due to climate change, it could further impact the integrity of ecological communities. To map the distribution of H. nehereus, we developed an ensemble species distribution model and projected the present and future habitat suitability in Chinese coastal waters. Annual mean benthic water temperature was identified as the most important variable affecting the projected distribution of H. nehereus, followed by water depth and salinity. Currently suitable habitats are along the coast from Guangxi Province to the southern Jiangsu Province. As climate changes, the southern portion of its distribution is predicted to recede with habitat losses, and the overall suitable habitat will shift northward. To avoid the potential impacts of H. nehereus redistribution, precautionary management based on species distribution modeling would help to maintain healthy marine ecosystems in the newly invaded areas.

     

Predicting the distributions of predator (snow leopard) and prey (blue sheep) under climate change in the Himalaya

Future climate change is likely to affect distributions of species, disrupt biotic interactions, and cause spatial incongruity of predator–prey habitats. Understanding the impacts of future climate change on species distribution will help in the formulation of conservation policies to reduce the risks of future biodiversity losses. Using a species distribution modeling approach by MaxEnt, we modeled current and future distributions of snow leopard (Panthera uncia) and its common prey, blue sheep (Pseudois nayaur), and observed the changes in niche overlap in the Nepal Himalaya. Annual mean temperature is the major climatic factor responsible for the snow leopard and blue sheep distributions in the energy‐deficient environments of high altitudes. Currently, about 15.32% and 15.93% area of the Nepal Himalaya are suitable for snow leopard and blue sheep habitats, respectively. The bioclimatic models show that the current suitable habitats of both snow leopard and blue sheep will be reduced under future climate change. The predicted suitable habitat of the snow leopard is decreased when blue sheep habitats is incorporated in the model. Our climate‐only model shows that only 11.64% (17,190 km²) area of Nepal is suitable for the snow leopard under current climate and the suitable habitat reduces to 5,435 km² (reduced by 24.02%) after incorporating the predicted distribution of blue sheep. The predicted distribution of snow leopard reduces by 14.57% in 2030 and by 21.57% in 2050 when the predicted distribution of blue sheep is included as compared to 1.98% reduction in 2030 and 3.80% reduction in 2050 based on the climate‐only model. It is predicted that future climate may alter the predator–prey spatial interaction inducing a lower degree of overlap and a higher degree of mismatch between snow leopard and blue sheep niches. This suggests increased energetic costs of finding preferred prey for snow leopards – a species already facing energetic constraints due to the limited dietary resources in its alpine habitat. Our findings provide valuable information for extension of protected areas in future.     

Ecological niche modeling of coastal dune plants and future potential distribution in response to climate change and sea level rise

Climate change (CC) and sea level rise (SLR) are phenomena that could have severe impacts on the distribution of coastal dune vegetation. To explore this we modeled the climatic niches of six coastal dunes plant species that grow along the shoreline of the Gulf of Mexico and the Yucatan Peninsula, and projected climatic niches to future potential distributions based on two CC scenarios and SLR projections. Our analyses suggest that distribution of coastal plants will be severely limited, and more so in the case of local endemics (Chamaecrista chamaecristoides, Palafoxia lindenii, Cakile edentula). The possibilities of inland migration to the potential ‘new shoreline’ will be limited by human infrastructure and ecosystem alteration that will lead to a ‘coastal squeeze’ of the coastal habitats. Finally, we identified areas as future potential refuges for the six species in central Gulf of Mexico, and northern Yucatán Peninsula especially under CC and SLR scenarios.     

气候变化对黄腹角雉潜在栖息地的影响

气候变化直接影响物种赖以生存的栖息地环境条件,进而影响物种的分布、数量和存活率。基于优化后最大熵(MaxEnt)模型预测气候变化下黄腹角雉(Tragopan caboti)过去、当前、未来时期的潜在栖息地格局。结果表明,降水量、温度、海拔是栖息地的主要影响因子。当前时期适宜栖息地面积较过去时期下降24.69%;未来2041—2060年间,共享社会经济路径(SSP)3-7.0与SSP5-8.5情景下黄腹角雉适宜栖息地面积较当前时期分别下降55.19%、58.10%。浙江、江西和福建是当前以及未来黄腹角雉核心适宜栖息地,适宜栖息地面积呈现下降的趋势,并往高纬度区域移动。     

Invasion of Old World Phragmites australis in the New World: precipitation and temperature patterns combined with human influences redesign the invasive niche

After its introduction into North America, Euro‐Asian Phragmites australis became an aggressive invasive wetland grass along the Atlantic coast of North America. Its distribution range has since expanded to the middle, south and southwest of North America, where invasive P. australis has replaced millions of hectares of native plants in inland and tidal wetlands. Another P. australis invasion from the Mediterranean region is simultaneously occurring in the Gulf region of the United States and some countries in South America. Here, we analysed the occurrence records of the two Old World invasive lineages of P. australis (Haplotype M and Med) in both their native and introduced ranges using environmental niche models (ENMs) to assess (i) whether a niche shift accompanied the invasions in the New World; (ii) the role of biologically relevant climatic variables and human influence in the process of invasion; and (iii) the current potential distribution of these two lineages. We detected local niche shifts along the East Coast of North America and the Gulf Coast of the United States for Haplotype M and around the Mississippi Delta and Florida of the United States for Med. The new niche of the introduced Haplotype M accounts for temperature fluctuations and increased precipitation. The introduced Med lineage has enlarged its original subtropical niche to the tropics‐subtropics, invading regions with a high annual mean temperature (> ca. 10 °C) and high precipitation in the driest period. Human influence is an important factor for both niches. We suggest that an increase in precipitation in the 20th century, global warming and human‐made habitats have shaped the invasive niches of the two lineages in the New World. However, as the invasions are ongoing and human and natural disturbances occur concomitantly, the future distribution ranges of the two lineages may diverge from the potential distribution ranges detected in this study.     

Macro-scale assessment of demographic and environmental variation within genetically derived evolutionary lineages of eastern hemlock (<Emphasis Type="Italic">Tsuga canadensis</Emphasis>), an imperiled conifer of the eastern United States

Eastern hemlock (Tsuga canadensis) occupies a large swath of eastern North America and has historically undergone range expansion and contraction resulting in several genetically separate lineages. This conifer is currently experiencing mortality across most of its range following infestation of a non-native insect. With the goal of better understanding the current and future conservation potential of the species, we evaluate ecological differences among populations within these genetically defined clusters, which were previously inferred using nuclear microsatellite molecular markers from 58 eastern hemlock populations. We sub-divide these clusters into four genetic zones to differentiate putative north-central, north-east and southeast (SE) and southwest evolutionary lineages in eastern hemlock. We use demographic data (relative abundance, mortality, and seedling regeneration) from the Forest Inventory Analysis program in conjunction with environmental data to model how these lineages respond to current and future climatic gradients. Ecologically meaningful relationships are explored in the intraspecific context of hemlock abundance distribution and then related to genetic variation. We also assess hemlock’s colonization likelihood via a long distance dispersal model and explore its future genetic and ecological conservation potential by combining the future suitable habitats with colonization likelihoods. Results show that future habitats under climate change will markedly decline for eastern hemlock. The remaining areas with higher habitat quality and colonization potential are confined to the SE, the genetic zone nearest the species’ putative glacial refugia, pointing to the need to focus our conservation efforts on this ecologically and genetically important region.     

水菜花种群潜在生境选择与空间格局预测

国家二级保护野生植物水菜花(Ottelia cordata)，喜生于清洁的水环境中，对环境变化极为敏感，是检验湿地环境及气候变化的关键指示物种之一，在我国仅零星分布于海南北部的火山熔岩湿地区，生存状况不容乐观。研究水菜花种群潜在生境选择及其空间格局演变，有利于加强濒危物种保护保育及湿地生态系统修复、管理。该研究基于GIS平台和MaxEnt模型，结合气候、地形和土壤因子，探究水菜花种群环境限制因子及其在气候变化背景下潜在适宜生境的演变格局。结果表明，水菜花种群对温差与降水量变化敏感，等温性、最冷季度降水量、土壤类型和年均降水量对水菜花种群分布影响显著；全新世中期-当前-2070年气候变化背景下，水菜花适宜生境面积先减小后增大，分布重心呈西南-东北-西南转移格局；未来气候情景下，水菜花种群高度和中度适宜生境缩减，低适宜生境增加，南部地区将出现新增适宜生境，东北、西北及西南部适宜生境将发生消减。该研究从气候环境角度论证了水菜花种群的潜在生境选择及空间变化特征，可为濒危物种保护保育、湿地管理及其生物多样性维护工作提供参考和指导。     

Cold tolerance of invasive freshwater snails,Pomacea canaliculata,P. maculata,and their hybrids helps explain their different distributions

相似文献   

Climate change, anthropogenic disturbance and the northward range expansion of Lactuca serriola (Asteraceae)

Aim The distribution range of Lactuca serriola, a species native to the summer‐dry mediterranean climate, has expanded northwards during the last 250 years. This paper assesses the influence of climate on the range expansion of this species and highlights the importance of anthropogenic disturbance to its spread. Location Central and Northern Europe. Methods Data on the geographic distribution of L. serriola were assembled through a literature search as well as through floristic and herbarium surveys. Maps of the spread of L. serriola in Central and Northern Europe were prepared based on herbarium data. The spread was assessed more precisely in Germany, Austria and Great Britain by pooling herbarium and literature data. We modelled the bioclimatic niche of the species using occurrence and climatic data covering the last century to generate projections of suitable habitats under the climatic conditions of five time periods. We tested whether the observed distribution of L. serriola could be explained for each time period, assuming that the climatic niche of the species was conserved across time. Results The species has spread northwards since the beginning of the 19th century. We show that climate warming in Europe increased the number of sites suitable for the species at northern latitudes. Until the late 1970s, the distribution of the species corresponded to the climatically suitable sites available. For the last two decades, however, we could not show any significant relationship between the increase in suitable sites and the distributional range change of L. serriola. However, we highlight potential areas the species could spread to in the future (Great Britain, southern Scandinavia and the Swedish coast). It is predominantly non‐climatic influences of global change that have contributed to its rapid spread. Main conclusions The observation that colonizing species are not filling their climatically suitable range might imply that, potentially, other ruderal species could expand far beyond their current range. Our work highlights the importance of historical floristic and herbarium data for understanding the expansion of a species. Such historical distributional data can provide valuable information for those planning the management of contemporary environmental problems, such as species responses to environmental change.     

Competitive interactions between an exotic and a native ladybeetle: a field cage study

We conducted field‐cage studies on the direct interactions between a coccinellid species native to North America, Coleomegilla maculata De Geer, and a species introduced from Asia, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae). We compared the mortality and weight gain of larvae of both species in field cages that enclosed one or both species with corn plants containing high or low aphid numbers. We did not find a significant effect of the presence of H. axyridis on the survival or weight gain of C. maculata, but H. axyridis larvae weighed more when kept with C. maculata for 5 days than when kept with equal numbers of conspecifics. This suggests that intraspecific competition was stronger for H. axyridis than the interspecific competition with C. maculata. The spatial distribution of C. maculata over the plants differed between single‐species and two‐species treatments in a manner that suggested that this species avoided interactions with H. axyridis.     

Ex Situ Conservation of Orchids in a Warming World

Whilst there is overwhelming scientific evidence that dramatic changes in regional climates are likely to occur throughout the 21st century, the scientific community remains uncertain how the effects of global heating will combine with other environmental factors to affect wild orchid populations. It is, however, likely that many populations will be affected adversely and that in situ conservation techniques by themselves will not be sufficient to prevent the extinction of many species. A range of complimentary ex situ strategies are discussed. Amongst these orchid seed banking has been shown to be an invaluable tool for conserving the maximum amount of genetic diversity in the minimum space and has the potential to enable the conservation of valuable material for possible re-introduction and habitat restoration programmes in the future. The Darwin Initiative project, ‘Orchid Seed Stores for Sustainable Use’ (OSSSU), is currently establishing a global network of orchid seed banks focussing initially on countries with high orchid biodiversity in Asia and Latin America. Particular reference is made to ex situ conservation in China, together with the urgent need to gather more data to determine which habitats and species are most at risk of extinction in the wild in the immediate future.     

Ant-mediated expansion of an obligate seeder species during the first years after fire

Most obligate seeder species build up a soil seed bank that is associated with massive seed germination in the year immediately after a fire. These species are also shade‐intolerant and disappear when vegetation cover closes, creating unsuitable conditions for seedling recruitment. The only way for these plants to expand their populations is when habitats suitable for seedling recruitment arise (i.e. in years immediately after a fire). However, short primary seed dispersal of obligate seeders does not allow these plants to colonise the suitable habitats, and these habitats can only be colonised by secondary seed dispersion. We hypothesised that Fumana ericoides, an obligate‐seeding small shrub, not only establishes abundantly in the first year after fire, but also expands its local range in the following years due to secondary dispersal by ants while suitable habitats are still available. We tested this hypothesis using experimental studies and a simulation model of potential population expansion in a recently burned area. Results showed that F. ericoides not only established prolifically in the year immediately after fire, but was also able to recruit new individuals and expand its population in the years following the fire, despite a low germination rate and short primary seed dispersal. Ant‐mediated seed dispersal and availability of suitable habitats were key factors in this phenomenon: ants redistributed seeds in suitable habitats while they were available, which accelerated the expansion of F. ericoides because new plants established far away from the core population.     

Impacts of climate change on the global potential distribution of two notorious invasive crayfishes

1. Invasive alien species and climate change are two of the most serious global environmental threats. In particular, it is of great interest to understand how changing climates could impact the distribution of invaders that pose serious threats to ecosystems and human activities.
2. In this study, we developed ensemble species distribution models for predicting the current and future global distribution of the signal crayfish Pacifastacus leniusculus and the red swamp crayfish Procambarus clarkii, two of the most highly problematic invaders of freshwater ecosystems worldwide. We collected occurrence records of the species, from native and alien established ranges worldwide. These records in combination with averaged observations of current climatic conditions were used to calibrate a set of 10 distinct correlative models for estimating the climatic niche of each species. We next projected the estimated niches into the geographical space for the current climate conditions and for the 2050s and 2070s under representative concentration pathway 2.6 and 8.5 scenarios.
3. Our species distribution models had high predictive abilities and suggest that annual mean temperature is the main driver of the distribution of both species. Model predictions indicated that the two crayfish species have not fully occupied their suitable climates and will respond differently to future climate scenarios in different geographic regions. Suitable climate for P. leniusculus was predicted to shift poleward and to increase in extent in North America and Europe but decrease in Asia. Regions with suitable climate for P. clarkii are predicted to widen in Europe but contract in North America and Asia.
4. This study highlights that invasive species with different thermal preference are likely to respond differently to future climate changes. Our results provide important information for policy makers to design and implement anticipated measures for the prevention and control of these two problematic species.

     

Modelling the spatial distribution of selected North American woodland mammals under future climate scenarios

1. North America has a diverse array of mammalian species. Model projections indicate significant variations in future climate conditions of North America, and the habitats of woodland mammals of this continent may be particularly sensitive to changes in climate.
2. We report on the potential spatial distributions of 13 wide-ranging, relatively common species of North American woodland mammals under future climate scenarios.
3. We examined the potential influence of the mean and seasonal climate variables on the distribution of species. Presence-only occurrence records of species, four predictor variables, two future climate scenarios (Representative Concentration Pathways 4.5 and 8.5), and two time steps (current and 2070) were used to build species’ distribution models using a maximum entropy algorithm (MaxEnt).
4. Our results suggested that overall, 11 of the 13 species are likely to gain climatically suitable space (regions where climate conditions will be similar to those of area currently occupied) at the continental scale, but American marten Martes americana and ‘woodland’ caribou Rangifer tarandus are likely to lose suitable climate range by 2070. Furthermore, climate space is likely to be expanding northwards under future climate scenarios for most of the mammals, and many jurisdictions in the border region between Canada and the USA are likely to lose iconic species, such as moose Alces alces. We identified regions as potential in situ and ex situ climate change refugia, which are increasingly considered to be important for biodiversity conservation.
5. The model results suggest significant implications for conservation planning for the 13 mammalian species under global climate change, especially at fine spatial scales. Numerous species that are presently common at their southern range edge will be functionally or completely extirpated in 50 years. The potential in situ and ex situ climate change refugia could provide an effective support for adaptive strategies aimed at species conservation planning.

     

Mapping potential wildlife habitats around Haro Abba Diko controlled hunting area,Western Ethiopia

Remote sensing and geographic information system technologies provide useful data to analyze and map potential wildlife habitats based on physical parameters collected from the field. HADCHA was established with a total area of 20,000 ha, while many more comparable potential wildlife habitats were left outside the area. This study aims to identify and map potential wildlife habitats around HADCHA. Data were collected using Landsat 5 thematic mapper and Sentinel‐2A satellite image, a digital elevation model with 30 m pixels downloaded from ASTER data, and existing GIS Shapefile layers. Thematic Mapper data were downloaded from USGS and processed with Erdas Imagine 2015 software. To evaluate potential wildlife habitat around HADCHA, habitat suitability parameters such as settlement, slope, water, and road buffer zones were used for habitat evaluation and mapping. Accordingly, 16,795 ha of potential wildlife habitats were identified and mapped on westwards of HADCHA. In the new PPWH, about 476.68 ha (2.84%) were moderately suitable, 14,119.17 ha (84.04%) suitable and 2,200.08 ha (13.10%) highly suitable but only 4.2 ha (0.02%) identified as unsuitable. Legal protection of the PPWH around HADCHA could increase the conservation of African buffalo, other mammals, and their habitats. While the mapped potential wildlife habitats had the potential to be parts of HADCHA, it was neglected and has not yet obtained conservation attention. The finding appeals for legal protection of the PPWH and expansion of HADCHA, which could maximize the conservation efforts taken to wild animals of the area. Neglecting this potential wildlife habitat for a long period of time exposed African buffalo and other large‐sized mammals to illegal hunting practices. Policymakers and conservationists shall revise and design the future action plan of HADCHA on how to expand the current‐controlled hunting area and maximize revenue generation from African buffalo and other potential trophy species of the area.     

Revisiting genetic structuring in spotted gums (genus Corymbia section Maculatae) focusing on C. maculata, an early diverged, insular lineage

Species delineation in the spotted gum complex was revisited focusing on Corymbia maculata. This study expands the range of C. maculata analysed with microsatellite markers to include populations from the north of the species range. It supported earlier findings that it is a cohesive genetic entity, well resolved from northern spotted gum taxa, Corymbia citriodora and Corymbia henryi; and inferences that its insularity is due to early lineage divergence and historical isolation. The northern extent of C. maculata sampled, as defined by chloroplast and nuclear genomes predominantly of C. maculata character, was the location of Kiwarrak, south of the Manning River near Taree in New South Wales. Trees from a recognised intergrade zone at the Yarratt locality, around 26 km north of Kiwarrak, also possessed a uniquely C. maculata chloroplast haplotype, but their nuclear genomes were predominantly of northern taxa ancestry. Range expansion of northern taxa leading to southerly gene movement into populations formerly C. maculata, would account for this apparent instance of chloroplast capture. Two subpopulations were identified in C. maculata, a northern population of which the Ourimbah locality was the most southerly studied, and a southern population of which Wingello was the most northerly locality studied. Diminished levels of northern taxa ancestry, i.e. C. citriodora or C. henryi, in individuals from the southern, relative to the northern subpopulation of C. maculata, suggested that secondary contact with northern taxa contributes to its substructure.