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1.
    
Habitat suitability models (HSMs) are popular and used for a wide variety of applications but most do not include analysis of the uncertainty of the model outputs. Additionally, some overfit the data and few allow the ability to fill data gaps with expert opinion. HEMI 1 addressed issues with overfitting data and allowed models to incorporate both occurrence data and expert opinion. HEMI 2 improves on HEMI 1 with a simplified interface and the ability to inject random noise into occurrence locations and environmental variable values to generate uncertainty maps. HEMI 2 uses Monte Carlo methods to perform uncertainty, validation, and sensitivity testing and generates mean and standard deviation habitat suitability maps.  相似文献   

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The prediction and definition of the conditions for the potentially suitable ecological niche of the subfamily Diaspidiinae was the main goal of this study. Our research was based on 283 specimens of all known species of assassin bugs belonging to the subfamily Diaspidiinae stored in European museum collections and a set of 21 environmental variables in the form of a 1 × 1 km grid covering Africa and Madagascar. Based on occurrence localities, as well as a digital elevation model and layer of the tree cover‐continuous fields, information about the distribution of each species is given. Using Maxent software, potentially useful ecological niches were modeled, which allowed for the creation of a map of the potential distribution of the members of this subfamily and for determining their climatic preferences. A jackknife test showed that annual precipitation, annual temperature range and tree cover‐continuous fields were the most important environmental variables affecting the distribution of the subfamily Diaspidiinae. An analysis of climatic preferences suggested that the representatives of the subfamily were linked mainly to the tropical climate. An analysis of environmental variables also showed that the subfamily preferred areas with herbaceous vegetation and some trees, and this preference is probably caused by the food preferences of their prey. On the basis of the museum data on the species occurrence, as well as ecological niche modeling methods, we provided new and valuable information on potentially suitable habitat and the possible range of distribution of the subfamily Diaspidiinae along with its climatic preferences.  相似文献   

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Hydrophis platurus xanthos is a marine reptile endemic to the inner basin of Golfo Dulce, Costa Rica, and one of only two sea snake taxa found in the New World. In this study we assessed several marine conditions that describe its habitat, and we define its geographical distribution range. We used 423 occurrence records of H. p. xanthos collected during multiple studies to model habitat suitability in Maxent considering water depth and 12 interpolated hydrographic variables: Beaufort wind force, sea surface temperature, and averages of temperature, salinity, dissolved oxygen, turbidity, and pH at 0.5 and 10 m based on probe readings collected in 2020 and 2021 at 68 sampling locations. We used area under the curve (AUC) to evaluate our Maxent models and the cloglog minimum training presence threshold to render our suitable habitat maps. The most influential environmental predictor was depth, but occurrences were also affected by hydrographic conditions. Indeed, a model excluding depth consistently identified only areas in and around the inner basin area as suitable, suggesting the sea snakes are not only restricted by depth but likely have adapted to water conditions that differ from those farther to the south and outside the gulf in the broader Pacific Ocean. Anthropogenic and climate-induced changes may already be impacting the marine environment of this single, isolated population. Our study offers the first quantitative evaluation of habitat suitability for H. p. xanthos and we estimate its extent of occurrence (282 km2) and current area of occupancy (260 km2) to inform conservation assessments and guide protection measures.  相似文献   

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Understanding the influence of environmental covariates on plant distribution is critical, especially for aquatic plant species. Climate change is likely to alter the distribution of aquatic species. However, knowledge of this change on the burden of aquatic macroorganisms is often fraught with difficulty. Ottelia, a model genus for studying the evolution of the aquatic family Hydrocharitaceae, is mainly distributed in slow-flowing creeks, rivers, or lakes throughout pantropical regions in the world. Due to recent rapid climate changes, natural Ottelia populations have declined significantly. By modeling the effects of climate change on the distribution of Ottelia species and assessing the degree of niche similarity, we sought to identify high suitability regions and help formulate conservation strategies. The models use known background points to determine how environmental covariates vary spatially and produce continental maps of the distribution of the Ottelia species in Africa. Additionally, we estimated the possible influences of the optimistic and extreme pessimistic representative concentration pathways scenarios RCP 4.5 and RCP 8.5 for the 2050s. Our results show that the distinct distribution patterns of studied Ottelia species were influenced by topography (elevation) and climate (e.g., mean temperature of driest quarter, annual precipitation, and precipitation of the driest month). While there is a lack of accord in defining the limiting factors for the distribution of Ottelia species, it is clear that water-temperature conditions have promising effects when kept within optimal ranges. We also note that climate change will impact Ottelia by accelerating fragmentation and habitat loss. The assessment of niche overlap revealed that Ottelia cylindrica and O. verdickii had slightly more similar niches than the other Ottelia species. The present findings identify the need to enhance conservation efforts to safeguard natural Ottelia populations and provide a theoretical basis for the distribution of various Ottelia species in Africa.  相似文献   

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  1. The range of a species is controlled by biotic and abiotic factors; both could have changed recently due to human activity.
  2. We used environmental modelling, morphometric and genetic data to interpret ecological responses at the species boundary of a pair of New Zealand grasshoppers with very different ranges; one widespread (Phaulacridium marginale) and one restricted to semi‐arid central/southern South Island (Phaulacridium otagoense).
  3. Climate‐ and habitat‐based distribution models for grasshoppers in the past (last glacial maximum), present and future (2070), in concert with modelling of vegetation patterns imply range and demographic expansion of P. marginale and stability of P. otagoense.
  4. mtDNA sequence revealed four main lineages with pronounced differences in genetic diversity and geographical range. The widespread lineage associated with P. marginale revealed a signature of range expansion but regionally restricted lineages were geographically structured at a fine scale. Within the narrow geographical range of P. otagoense, three mtDNA lineages resulted in high diversity, more typical of large stable populations.
  5. Geometric analysis of pronotum shape identified individuals from a region of sympatry with mixed characteristics. Mismatch of phenotype, mtDNA lineage and nuclear DNA sequence indicates introgression between grasshopper species now in contact. This appears to be accompanied by P. otagoense range reduction through ecological competition.
  6. Deforestation by people starting ∼800 years ago best explains range change and resulting hybridisation of these grasshoppers. Anthropogenic habitat modification can have indirect consequences on insect biodiversity and conservation by enabling introgression between formerly separate populations and species.
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  1. The white-clawed crayfish (Austropotamobius pallipes) is globally endangered due to the impacts of habitat modification and fragmentation, water pollution, climate change, and invasive species, particularly the signal crayfish (Pacifastacus leniusculus). These pressures have caused the decline of A. pallipes populations in Europe, demonstrating the importance of predicting the species' potential distribution under current and future conditions. Focusing on the watercourses of mainland France, we aimed to identify suitable areas for A. pallipes to guide the conservation of current populations and future introduction actions or protection measures.
  2. We applied ecological niche modelling to model the potential distribution of both A. pallipes and P. leniusculus and identified locations suitable for A. pallipes only. We also assessed the potential distribution of the species under two representative concentration pathway (RCP) scenarios: RCP 2.6 and RCP 8.5, respectively describing low-warming and high-warming conditions.
  3. We found that A. pallipes and P. leniusculus exploit equivalent niches in France. Despite this, under current conditions, about 5% of the study area simultaneously records a high suitability for A. pallipes and a low suitability for P. leniusculus and is therefore of significant conservation interest. This percentage remains relatively stable under RCP 2.6 for 2050 and 2100, but decreases to 2% under RCP 8.5 for 2100.
  4. Ecological niche modelling can supply crucial guidance for conservation actions aimed at protecting endangered species at a national scale by identifying sites most suitable for protection and sites where climate change and invasive species constitute a threat.
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北戴河地区鸻形目鸟类觅食生境动态变化   总被引:2,自引:1,他引:2       下载免费PDF全文
倪永明  李湘涛 《生态学报》2009,29(4):1731-1737
生境破坏是目前野生动物保护面临主要问题,加强生境恢复与重建对保护珍稀物种具有重要意义.将3S技术运用到北戴河地区鸻形目鸟类觅食生境评价中,分析了近20a(1987~2006年)北戴河地区鸻形目鸟类觅食生境的动态变化,结果:鸻形目鸟类最适宜觅食生境和适宜觅食生境分布面积在1993年最大;觅食生境变化以1993年为分水岭;最适宜觅食生境和适宜生分布面积呈下降趋势(倒U形分布),不适宜觅食生境分布面积呈增加趋势(U形分布).北戴河地区鸻形目鸟类觅食生境变化主要影响因素是人类活动增加.  相似文献   

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Climate change is exerting unprecedented impacts on marine habitats, and many sessile invertebrate species, such as the endangered giant clam Tridacna maxima, are particularly sensitive to climate driven changes in their environment. Understanding its spatial distribution and conservation requirements is of crucial significance in formulating effective protection strategies. However, the species has been extensively harvested and depleted in many regions, leading to its listing as endangered species by the International Union for Conservation of Nature (IUCN). While marine protected areas (MPAs) are considered effective conservation tools, it remains uncertain whether existing MPAs adequately protect these vulnerable giant clams. To enhance the management and conservation of this species, we employed a Species Distribution Models (SDMs) approach, integrating occurrence records of T. maxima with environmental variables, to predict its potential distribution based on habitat suitability and capture spatiotemporal changes. Based on geographical and genetic variations, the T. maxima in the Indo-Pacific core region is primarily divided into two populations: the East Indian Ocean-South China Sea population (EIOS) and the West Pacific-Indonesia population (WPI). We first quantified realized niche to reveal significant differences in ecological niche space among different populations. Subsequently, SDMs were constructed at both species and population levels, demonstrating that population-level SDMs provide more reliable predictions of population distributions due to differential responses to climatic predictor variables. Finally, we conducted an assessment to identify conservation gaps for T. maxima beyond the existing MPAs and proposed recommendations for future establishment of MPAs within the current framework. Based on these findings, appropriate conservation policies have been proposed to effectively protect the habitat of different geographical populations of T. maxima. Additionally, spatiotemporal predictions of habitat suitability provide crucial information for developing adaptive management strategies for T. maxima in response to climate change, including designing new protected areas and adjusting the location and extent of existing protected areas based on their geographical distribution.  相似文献   

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Understanding the impacts of meteorological factors on giant pandas is necessary for future conservation measures in response to global climate change. We integrated temperature data with three main habitat parameters (elevation, vegetation type, and bamboo species) to evaluate the influence of climate change on giant panda habitat in the northern Minshan Mountains using a habitat assessment model. Our study shows that temperature (relative importance = 25.1%) was the second most important variable influencing giant panda habitat excepting the elevation. There was a significant negative correlation between temperature and panda presence (ρ = −0.133, P < 0.05), and the temperature range preferred by giant pandas within the study area was 18–21°C, followed by 15–17°C and 22–24°C. The overall suitability of giant panda habitats will increase by 2.7%, however, it showed a opposite variation patterns between the eastern and northwestern region of the study area. Suitable and subsuitable habitats in the northwestern region of the study area, which is characterized by higher elevation and latitude, will increase by 18007.8 hm2 (9.8% habitat suitability), while the eastern region will suffer a decrease of 9543.5 hm2 (7.1% habitat suitability). Our results suggest that increasing areas of suitable giant panda habitat will support future giant panda expansion, and food shortage and insufficient living space will not arise as problems in the northwest Minshan Mountains, which means that giant pandas can adapt to climate change, and therefore may be resilient to climate change. Thus, for the safety and survival of giant pandas in the Baishuijiang Reserve, we propose strengthening the giant panda monitoring program in the west and improving the integrity of habitats to promote population dispersal with adjacent populations in the east.  相似文献   

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Although numerous species distribution models have been developed, most were based on insufficient distribution data or used older climate change scenarios. We aimed to quantify changes in projected ranges and threat level by the years 2061–2080, for 12 European forest tree species under three climate change scenarios. We combined tree distribution data from the Global Biodiversity Information Facility, EUFORGEN, and forest inventories, and we developed species distribution models using MaxEnt and 19 bioclimatic variables. Models were developed for three climate change scenarios—optimistic (RCP2.6), moderate (RCP4.5), and pessimistic (RPC8.5)—using three General Circulation Models, for the period 2061–2080. Our study revealed different responses of tree species to projected climate change. The species may be divided into three groups: “winners”—mostly late‐successional species: Abies alba, Fagus sylvatica, Fraxinus excelsior, Quercus robur, and Quercus petraea; “losers”—mostly pioneer species: Betula pendula, Larix decidua, Picea abies, and Pinus sylvestris; and alien species—Pseudotsuga menziesii, Quercus rubra, and Robinia pseudoacacia, which may be also considered as “winners.” Assuming limited migration, most of the species studied would face a significant decrease in suitable habitat area. The threat level was highest for species that currently have the northernmost distribution centers. Ecological consequences of the projected range contractions would be serious for both forest management and nature conservation.  相似文献   

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Geographical distribution and diversity patterns of bird species are influenced by climate change. The Rouget's rail (Rougetius rougetii) is a ground-dwelling endemic bird species distributed in Ethiopia and Eritrea. It is a near-threatened species menaced by habitat loss, one of the main causes of population declines for bird species. The increasing effects of climate change may further threaten the species’ survival. So far, the spatial distribution of this species is not fully documented. With this study, we develop current potential suitable habitat and predict the future habitat shift of R. rougetii based on environmental data such as bioclimatic variables, population density, vegetation cover, and elevation using 10 algorithms. We evaluated the importance of environmental factors in shaping the bird's distribution and how it shifts under climate change scenarios. We used 182 records of R. rougetii from Ethiopia and nine bioclimatic, population density, vegetation cover, and elevation variables to run the 10 model algorithms. Among 10 algorithms, eight were selected for ensembling models according to their predictive abilities. The current suitable habitats for R. rougetii were predicted to cover an area of about 82,000 km2 despite being highly fragmented. The model suggested that temperature seasonality (bio4), elevation, and mean daily air temperatures of the driest quarter (bio9) contributed the most to delimiting suitable areas for this species. R. rougetii is sensitive to climate change associated with elevation, which leads shrinking distribution of suitable areas. The projected spatial and temporal pattern of habitat loss of R. rougetii suggests the importance of climate change mitigation and implementing long-term conservation and management strategies for this threatened endemic bird species.  相似文献   

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The sungazer (Smaug giganteus) is a strict grassland specialist lizard endemic to South Africa's highveld grasslands. It is currently listed as Vulnerable (IUCN) and is primarily threatened by anthropogenic activities. Because sungazers are habitat specialists, climate change may be detrimental to the species, considering their life-history traits, and the area of available suitable habitat. We assessed how climate change may impact the sungazers' geographic range by first producing an ecological niche model (ENM) for the species within a buffered region of its extent of occurrence (buffered EOO). The ENM was then projected to 2040, 2060, 2080 and 2100 under two climate change scenarios using Shared Socioeconomic Pathways (SSP); SSP245 (moderate-case) and SSP585 (worst-case). A mean ensemble of three global circulation models for each time period and scenario was used to create habitat suitability maps which were refined using a natural grassland variable overlay. Resulting maps were clipped to the sungazers' EOO and interpreted distribution. Within the interpreted distribution, models predicted an area of 10 198 km2 of current suitable habitat. At this scale, future habitat suitability is predicted to remain relatively stable (area: 9910 km2; 3% decline) under SSP245 by 2100. However, a 24% decline (area: 7705 km2) in habitat suitability was predicted under SSP585. Within the buffered EOO, habitat suitability increased in south-western regions, which was more prominent under SSP585. Although this finding suggests that sungazers could track favourable conditions, their life history and low dispersal ability makes climate tracking unlikely. Because sungazers only occur in primary grasslands, regions dominated by agricultural activities, further land use developments are likely to affect the species survival. Thus, careful conservation management is essential, and we recommend the establishment of protected areas with cognizance of our predictions for current and future suitable habitat within the sungazers' interpreted distribution.  相似文献   

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The most common approach to predicting how species ranges and ecological functions will shift with climate change is to construct correlative species distribution models (SDMs). These models use a species’ climatic distribution to determine currently suitable areas for the species and project its potential distribution under future climate scenarios. A core, rarely tested, assumption of SDMs is that all populations will respond equivalently to climate. Few studies have examined this assumption, and those that have rarely dissect the reasons for intraspecific differences. Focusing on the arctic-alpine cushion plant Silene acaulis, we compared predictive accuracy from SDMs constructed using the species’ full global distribution with composite predictions from separate SDMs constructed using subpopulations defined either by genetic or habitat differences. This is one of the first studies to compare multiple ways of constructing intraspecific-level SDMs with a species-level SDM. We also examine the contested relationship between relative probability of occurrence and species performance or ecological function, testing if SDM output can predict individual performance (plant size) and biotic interactions (facilitation). We found that both genetic- and habitat-informed SDMs are considerably more accurate than a species-level SDM, and that the genetic model substantially differs from and outperforms the habitat model. While SDMs have been used to infer population performance and possibly even biotic interactions, in our system these relationships were extremely weak. Our results indicate that individual subpopulations may respond differently to climate, although we discuss and explore several alternative explanations for the superior performance of intraspecific-level SDMs. We emphasize the need to carefully examine how to best define intraspecific-level SDMs as well as how potential genetic, environmental, or sampling variation within species ranges can critically affect SDM predictions. We urge caution in inferring population performance or biotic interactions from SDM predictions, as these often-assumed relationships are not supported in our study.  相似文献   

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  1. Sipha (Rungsia) maydis, Sipha (Rungsia) elegans, Sipha (Sipha) glyceriae and especially Sipha (Sipha) flava are considered to be virus vectors and serious pests of crops and pasture grasses. Ecological niche modelling, a useful tool for assessing potential geographical distributions of species, was used to predict the risk of invasion of these four species of the Siphini (Hemiptera, Aphididae) on a global scale.
  2. The maximum entropy model based on associations between unique occurrence localities and a set of environmental variables was used. Obtained models of potentially suitable habitats, based only on climatic variables, suggest that favourable conditions for each species may be present on every continent. However, S. (S.) flava appears to be potentially the most widespread species. Moreover, the resulting maps provide important information on the corridors by which invasive species are able to penetrate into new areas.
  3. A mean of the area under the receiver operating characteristic curve at the levels of 0.937, 0.947, 0.968, 0.937 for S. (R.) maydis, S. (R.) elegans, S. (S.) glyceriae and S. (S.) flava, respectively, indicated a high level of discriminatory power of the maximum entropy model.
  4. A jackknife test indicated that the precipitation of the coldest quarter with the highest gain value was the most important environmental variable restricting the expansion of the studied species.
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