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1.
Predicting the potential distribution of medicinal plants in response to climate change is essential for their conservation and management. Contributing to the management program, this study aimed to predict the distribution of two threatened medicinal plants, Fritillaria cirrhosa and Lilium nepalense. The location of focal species gathered from herbarium specimen housed in different herbaria and online databases were geo-referenced and checked for spatial autocorrelation. The predictive environmental variables were selected, and MaxEnt software was used to model the current and future distributions of focal species. Four Representative Concentration Pathway (RCP) trajectories of the BCC-CSM1.1 model were used as the future (2050) projection layer. The MaxEnt modelling delineated the potential distribution of F. cirrhosa and L. nepalense. The current suitability is projected towards Central and Eastern Hilly/Mountainous regions. Both species gain maximum suitability in RCP 4.5 which decline towards other trajectories for L. nepalense. Overall, both the focal species shift towards the north-west, losing their potential habitat in hilly and lower mountainous regions by 2050 across all trajectories. Our results highlight the impact of future climate change on two threatened and valuable species. The results can be further useful to initiate farming of these medicinally and economically important species based on climatically suitable zone and for designing a germplasm conservation strategy.  相似文献   

2.
Arjinshan National Nature Reserve (ANNR) is one of 3 refuges of the endemic ungulates Tibetan wild ass (Equus kiang), Chiru (Pantholops hodgsonii) and wild yak (Bos mutus) that are endangered by natural and anthropogenic factors in the Qinghai-Tibetan Plateau (QTP). Identifying habitat suitability is critical for species protection management. We used a GIS-based niche model to delimit and classify habitat suitability using an integrated assessment system, which included 9 biotic and abiotic factors. We divided the research area into 4 habitat types for these ungulates: (1) high suitability habitat; (2) moderate suitability habitat; (3) low suitability habitat; and (4) unsuitable area. Results suggested that chiru have the most areas of high and moderate suitability habitats while Tibetan wild ass had the largest areas of low suitability habitat and unsuitable area. Wild yak had the largest area of moderate and low suitability habitat, but high suitability habitats for wild yak were smaller than those of other 2 ungulates. There was overlap of high-quality habitat for the three kinds of ungulates in the vicinity of Kardun inspection station, which could be regarded as the core area for the coexistence and conservation of these endangered ungulate populations.  相似文献   

3.
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.  相似文献   

4.
《山地科学学报》2020,17(1):68-82
Global climate change poses a new challenge for species and can even push some species toward an extinction vortex. The most affected organisms are those with narrow tolerance to the climatic factors but many large mammals such as ungulates with a wider ecological niche are also being affected indirectly. Our research mainly used wild sheep in central Iran as a model species to explore how the suitable habitats will change under different climatic scenarios and to determine if current borders of protected areas will adequately protect habitat requirements. To create habitat models we used animal-vehicle collision points as an input for species presence data. We ran habitat models using Max Ent modeling approach under different climatic scenarios of the past, present and future(under the climatic scenarios for minimum(RCP2.6) and maximum(RCP8.5) CO2 concentration trajectories). We tried to estimate the overlap and the width of the ecological niche using relevant metrics. In order to analyze the effectiveness of the protected areas, suitable maps were concerted to binary maps using True Skill Statistic(TSS) threshold and measured the similarity of the binary maps for each scenario using Kappa index. In order to assess the competence of the present protected areas boundary in covering the distribution of species, two different scenarios were employed, which are ensemble scenario 1: an ensemble of the binary maps of the species distribution in Mid-Holocene, present, and RCP2.6;and ensemble scenario 2: an ensemble of binary suitability maps in Mid-Holocene, present, and RCP8.5. Then, the borders of modeled habitats with the boundaries of 23 existing protected areas in two central provinces in Iran were compared. The predicted species distribution under scenario 1(RCP2.6) was mostly similar to its current distribution(Kappa = 0.53) while the output model under scenario 2(RCP8.5) indicated a decline in the species distribution range. Under the first ensemble scenario, current borders of the protected areas in Hamedan province showed better efficiency to cover the model species distribution range. Analyzing Max Ent spatial models under the second climatic scenario suggested that protected areas in both Markazi and Hamedan provinces will not cover "high suitability" areas in the future. Modeling the efficiency of the current protected areas under predicted future climatic scenarios can help the related authorities to plan conservation activities more efficiently.  相似文献   

5.
Habitat 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 0.311, 0.260, 0.198 and 0.125, respectively. Suitable and sub-suitable habitats cover 4431.80 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 studyarea. 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.  相似文献   

6.
A habitat model has been widely used to manage marine species and analyze relationship between species distribution and environmental factors.The predictive skill in habitat model depends on whether the models include appropriate explanatory variables.Due to limited habitat range,low density,and low detection rate,the number of zero catches could be very large even in favorable habitats.Excessive zeroes will increase the bias and uncertainty in estimation of habitat.Therefore,appropriate explanatory variables need to be chosen first to prevent underestimate or overestimate species abundance in habitat models.In addition,biotic variables such as prey data and spatial autocovariate(SAC) of target species are often ignored in species distribution models.Therefore,we evaluated the effects of input variables on the performance of generalized additive models(GAMs) under excessive zero catch(70%).Five types of input variables were selected,i.e.,(1) abiotic variables,(2) abiotic and biotic variables,(3) abiotic variables and SAC,(4) abiotic,biotic variables and SAC,and(5) principal component analysis(PCA) based abiotic and biotic variables and SAC.Belanger 's croaker Johnius belangerii is one of the dominant demersal fish in Haizhou Bay,with a large number of zero catches,thus was used for the case study.Results show that the PCA-based GAM incorporated with abiotic and biotic variables and SAC was the most appropriate model to quantify the spatial distribution of the croaker.Biotic variables and SAC were important and should be incorporated as one of the drivers to predict species distribution.Our study suggests that the process of input variables is critical to habitat modelling,which could improve the performance of habitat models and enhance our understanding of the habitat suitability of target species.  相似文献   

7.
Siberian larch (Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas (EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors (soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.  相似文献   

8.
We present a GIS-based habitat suitability index (HSI) model to identify suitable areas for Zostera marina L. restoration in the subtidal zone of Xiaoheishan Island. The controlling factors in the model, in order of importance, are Secchi depth, sediment composition, water temperature, salinity, current velocity, water depth and nutrient quality. Specific factor piecewise functions have been used to transform parameter values into normalized quality indexes. The weight of each factor was defined using expert knowledge and the analytic hierarchy process (AHP) method. All of the data thus obtained were interpolated using the inverse distance weighted (IDW) interpolation method to create maps for the entire region. In this study, the analysis of habitat suitability in the subtidal zone of Xiaoheishan Island was conducted for four seasons. According to the GIS-based HSI model, the optimal habitat of Zostera marina L. appears in spring, although habitat remains suitable all year round. On the whole, the optimum site for eelgrass restoration is located in the eastern region, followed by the western and southern regions. We believe that the GIS-based HSI model could be a promising tool to select sites for Zostera marina L. restoration and could also be applicable in other types of habitat evaluation.  相似文献   

9.
We built a classification tree(CT) model to estimate climatic factors controlling the cold temperate coniferous forest(CTCF) distributions in Yunnan province and to predict its potential habitats under the current and future climates, using seven climate change scenarios, projected over the years of 2070-2099. The accurate CT model on CTCFs showed that minimum temperature of coldest month(TMW) was the overwhelmingly potent factor among the six climate variables. The areas of TMW-4.05 were suitable habitats of CTCF, and the areas of -1.35 TMW were non-habitats, where temperate conifer and broad-leaved mixed forests(TCBLFs) were distribute in lower elevation, bordering on the CTCF. Dominant species of Abies, Picea, and Larix in the CTCFs, are more tolerant to winter coldness than Tsuga and broad-leaved trees including deciduous broad-leaved Acer and Betula, evergreen broadleaved Cyclobalanopsis and Lithocarpus in TCBLFs. Winter coldness may actually limit the cool-side distributions of TCBLFs in the areas between -1.35°C and -4.05°C, and the warm-side distributions of CTCFs may be controlled by competition to the species of TCBLFs. Under future climate scenarios, the vulnerable area, where current potential(suitable + marginal) habitats(80,749 km~2) shift to nonhabitats, was predicted to decrease to 55.91%(45,053 km~2) of the current area. Inferring from the current vegetation distribution pattern, TCBLFs will replace declining CTCFs. Vulnerable areas predicted by models are important in determining priority of ecosystem conservation.  相似文献   

10.
This study provides a checklist of species distributed at the altitude gradient of Moghan-Sabalan rangelands in Ardabili province, Northwest Iran. We evaluated the changes in species composition, growth types of species, Raunkiaer’s life forms, geographical distribution, threat and endemicity status, and palatability of species along two altitudinal gradients in the sampling plots, which were conducted in eleven sites/habitats with 300 meters above sea level (masl) altitude intervals (from 100 to 3300 masl). We assessed the plant species composition with special reference to the gradient analysis, and identified overall 396 species, which was comprising 44 families and 194 genera. Results showed that Asteraceae family is by far the most species-rich family, followed by Poaceae, Fabaceae, Caryophyllaceae and Brassicaceae. Among the genera, Astragalus is the most diverse genus, followed by Allium, Veronica and Bromus, Galium, Silene and Ranunculus. Results indicated that the number of species increased as the altitude increased to 1200–1500 masl, but then starts to decline to 3300 masl. Family-to-genera ratio was 1:4.4, the family-tospecies ratio was 1:9, and the genera-to-species ratio was 1:2.04. Growth type of species analysis shows that the frequency of perennial plants was higher in the study area followed by annual species while the lower group was biennial species. The number of annuals showed a decreasing trend towards higher altitude. Hemicryptophytes and therophytes were the most frequent life forms constituted each with (41.9%). Hemicryptophytes showed an increasing trend with altitude, while therophytes showed a decreasing trend with altitude increase, followed by geophytes, chamaephytes, and phanerophytes. Results showed more than half of the species of the study area belonged to Iran-Turanian region and these species showed an increasing trend with altitude. In contrast, Sahara-Sindian species comprise a minor component of the spectrum, with decreasing trend with altitude. The rare and endangered species out of the surveyed taxonomic groups comprised 53 species in total which 29 of them are considered lower risk (LR), 13 data deficient (DD), 5 vulnerable (Vu) and with 3 rare (R) and identified endemic plants comprised 24 species. Some 56.6% species were identified as class III, 22.6% were class I and 20.8% were class II as the palatability variation. Moghan-Sabalan rangelands require strong conservation management policies in case of species loss and changing natural communities due to the occurrence of conversion into cropland, over-grazing and other anthropogenic effects.  相似文献   

11.
基于地理探测器的大熊猫生境适宜度评价模型及验证   总被引:4,自引:0,他引:4  
动物生境适宜度评价对于野生动物生境保护十分重要。基于物种活动点来建模的生态位模型是目前应用最广泛的动物生境评价方法,但该方法不能直接表达生境适宜度与环境因子间具有生态学意义的数量关系。本文以雅安地区为例,提出一种新的大熊猫(Ailuropoda melanoleuca)生境适宜度评价方法,选取海拔、坡度、坡向、地形指数、距水源距离、植被类型、主食竹及距公路距离8个环境因子,引入地理探测器,在分别基于MAXENT模型和层次分析法(The Analytic Hierarchy Process,AHP)所构建生境适宜度模型的基础上,通过4个地理探测器(风险探测器、因子探测器、生态探测器和交互作用探测器)探寻大熊猫生境与各环境因子间的关系以及环境因子对大熊猫生境的影响机理,并将其预测结果与单一MAXENT模型和AHP法进行对比。结果表明:(1)AHP、AHP-Geogdetector、MAXENT和MAXENT-Geogdetector模型总体评价精度分别为85.6%、86.5%、91.3%和94.2%,kappa系数分别为0.699、0.718、0.821和0.882,AUC值分别为0.902、0.928、0.949和0.966,模型所预测的适宜和较适宜区与实际分布区重叠比分别为63.66%、61.30%、76.70%和90.10%,说明AHP-Geogdetector和MAXENT-Geogdetector模型精度均比相应的单一模型有所提高,且MAXENT-Geogdetector模型精度最高;(2)基于地理探测器的大熊猫生境适宜度评价模型能以“生境适宜度和环境因子间具有生态学意义的数量关系”的形式直接体现环境因子对动物生境利用的生态学作用,具有较好的生态学可解释性。因此,用地理探测器进行大熊猫生境适宜度评价具有较好的可行性。  相似文献   

12.
The anthropogenic managements of forest have created a network of roads resulting in the loss and alternation of habitat. To better understand road's impact on animal habitats, we assessed the habitat pattern of sables (Martes zibellina), one of rodents within national first-class protected species, when roads are considered in Huzhong area in Da Hinggan Mountains, northeastern China. Em- ploying published literatures about behavior ecology, aerial photographs and forest stand maps, we classified the study area into three habitat types including best-suitable, suitable and unsuitable habitats based on sable habitat requirements at the landscape scale includ- ing four variables derived from forest source map with attribute database. Results indicated the loss and significant fragmentation of best-suitable habitat and home range habitat when roads, especially 150 m avoidance distance of roads, were considered. The roads re- duced and fragmented highly suitable habitats more significantly during earlier development period than the later development period. Additionally, the suitable area percentage increased with increasing distance to roads. This study helped to identify the suitable area for sables and location of sable population. Also, this study suggested the passage construction and road management involving road clo- sure and removal will reduce the fragmentation functionally and benefit the sable population.  相似文献   

13.
Climate change will affect the geographic distribution and richness of species at different spatial and temporal scales. We applied Maximum entropy(MaxEnt) modeling to predict the potential influence of climatic change on the current and future distribution of the important mountainous tree species Moringa peregrina(Forssk.) Fiori. The Maxent model performed better than random models for the species with the training and test AUC(Area Under the receiver-operating characteristic Curve) values of 0.96 and 0.90, respectively. Jackknife test and response curves showed that the distribution of the species negatively correlates with higher altitudes and precipitation in October and November. Moreover, it positively correlates with the total annual precipitation and precipitation in January. Under current and future climatic conditions, our model predicted habitat gains for M. peregrina towards the coastal northern and southern limits of its distribution. The potentially suitable habitats, under future climate projections, are currently characterized by elevations of 1000 m a.s.l. and total annual precipitation of 80-225 mm/year. Moderate and high potential habitat suitability will increase by 5.6%-6% and 2.1%-2.3%, under RCP2.6 and RCP4.5 scenario, respectively. The results indicated that the habitat suitability of M. peregrina would increase with increasing climate warming, particularly under RCP2.6 scenario. We recommend sustainable conservation and cultivation of Moringa peregrina in its current habitats along the Red Sea mountains.  相似文献   

14.
Paeonia delavayi is a wild tree peony species endemic to high-altitude regions in southwestern China. Recent agricultural land expansion, however, not only causes its dwindling population size, but also poses a severe threat to its long-term persistence. Since our knowledge of the reproductive biology of P. delavayi is very limited, and some management misconceptions have further exacerbated the already worrisome situation, the aim of the present study is to provide some scientific evidence regarding habitat preference and breeding system of P. delavayi, and to help correct some management misconceptions. Specifically, morphological traits of P. delavayi populations growing in two different habitats (i.e., the open area versus forest understory), including basal stem diameter, plant height and flower numbers per plant, were measured and compared with each other. A range of floral manipulation experiments was further conducted to study the extent of self-compatibility and pollen limitation. The results showed that P. delavayi preferred the open habitat over forest understory as it generally grew bigger with thicker stems, and produced a higher number of flowers in the former habitat. Therefore, the open habitat should receive immediate priority for conservation action instead of being converted to agricultural land; also, P. delavayi is pollen limited, as evidenced by the fact that experimental flowers receiving supplemental non-self pollen generally displayed elevated seed production than flowers subjected to other treatments (e.g., non-supplemental self pollen, non-supplemental non-self pollen and supplemental self pollen), which is consistent with reported observations that alpine plants are more likely to be pollen-limited than lowland plants. We suggest that human intervention might be necessary to guarantee the long-term persistence of P. delavayi as harsh alpine environment, intense competition for pollinators and different anthropogenic perturbations co-limit its reproductive success.  相似文献   

15.
Land use suitability analysis plays an important role in sustainable land use and solving environmental problems caused by rapid urban development.A land use suitability mapping approach for town development planning in hilly areas was constructed based on two multi-criteria evaluation methods:Weighted Linear Combination(WLC)and Ordered Weighted Averaging(OWA),to comparatively evaluate and map land use suitability of Tangshan new town in Nanjing,China.Fourteen evaluation factors related to topographic,environmental,socio-economics and historical sites data were used as suitability criteria.The analytic hierarchy process(AHP)method and GIS techniques were integrated into the evaluation models to create the land use suitability map for town development planning.The results of WLC approach showed that 11.4%of the total area is highly suitable while the 48.6%is unsuitable.The results of WLC and OWA approach showed the distribution of degree of land use suitability is almost the same.The areas located at the southern and eastern flat regions are highly suitable for land use,whereas the areas close to the mountain forests,steep slopes,waters,and hot springs,have lower suitability for land use.Sensitivity analysis indicated that the suitability results of the two proposed methods are robust.Indirect validation was achieved by mutual comparison of suitability maps derived from the WLC and OWA methods.It demonstrated that the overall agreement is 90.81%and kappa coefficient is 0.81,indicating that both methods provide very similar spatial suitability distributions.By overlaying the resultant map with the previous master plan map of Tangshan new town,the overlay map once again indicated a satisfactory ecological fit between the two maps.At last,several recommendations are proposed aiming at improving the long-term town development plan for Tangshan new town.  相似文献   

16.
Abies georgei var. smithii is an important plant species in Southeast Tibet, China. It has high ecological value in terms of biodiversity protection, as well as soil and water conservation. We analyzed the spatial pattern and associations of A. georgei var. smithii populations at different growth stages by using Ripley’s L function for point pattern analysis. The diameter structure was a nearly reverse ‘J’ shape. The amount of saplings and medium-sized trees accounts for a large part of the entire population, suggesting a high regeneration rate and an expanding population. In the transition from saplings to medium trees or to large trees, saplings show a significant aggregation distribution at small scales, while medium trees and large trees show a random distribution. There are significant inverse associations between saplings and medium trees and large trees at small scales, while there are no obvious associations between medium trees and large trees. The natural regeneration was affected by interspecific competition, and it was also affected by intraspecific competition. The joint effects of biological characteristics and environmental factors contribute to the spatial distribution pattern and associations of this A. georgei var. smithii population.  相似文献   

17.
Ecological variables play a significant role in determining the diversity and distribution of any living organism on earth. Lichens are not exceptional and are quite sensitive in comparison to other organisms; hence the present study focuses on the impact of ecological variables on the diversity and distribution of epiphytic macrolichens colonizing Quercus leucotrichophora across eight different sites (50 m × 50 m) in Thal Ke Dhar forest, Kumaun Himalaya, Uttarakhand, India. For sampling of macrolichens, 200 trees (25 trees from each site) of Q. leucotrichophora were selected from each site and five quadrats of 5 cm × 10 cm (1000 quadrats in totality) were drawn at the tree trunk. From all the sampled trees, a total of 54 species of epiphytic macrolichens belonging to 18 genera and five families were recorded. Various ecological variables, namely altitude, aspect, slope, diameter at breast height (DBH), and lopping percent (partial cutting of the twigs as disturbance), were also analyzed to investigate their influence on macrolichen species composition and distribution pattern in the study area. For the determination of relationships between these variables, statistical analysis, namely Pearson’s Correlation Coefficient, Polynomial regression analysis and Principal Component Analysis (PCA) were performed. Out of all variables, lopping was significantly correlated to species richness of epiphytic macrolichens (0.712*, p<0.05) and it was confirmed by Pearson’s Correlation Coefficient. Despite of having high anthropogenic pressure or impact through lopping, the maximum number of macrolichen species was recorded at elevation 2267 meter above sea level (m asl). The present study revealed that besides other ecological variables, lopping practices can act as a key parameter in controlling the diversity and distribution not only of epiphytic macrolichens but also of other life forms such as bryophytes, pteridophytes, insects, birds etc. and can be either negatively or positively correlated.  相似文献   

18.
Massive geological landslides and unstable landslide areas were triggered by the 2008 Wenchuan earthquake. These landslides caused deaths, damaged infrastructure and threatened endanger species. This study analyzed the impact of landslides on giant pandas and their habitats from the following aspects: threatening pandas‘ lives, damaging pandas‘ habitat, influencing giant panda behavior, increasing habitat fragmentation; the final aspect, and blocking gene flow by cutting off corridors. A habitat suitability map was created by integrating the landslide factors with other traditional factors based on a logistics regression method. According to the landslide inventory map, there are 1313 landslides, 818 rock debris flows, 117 rock avalanches and 43 mud flows occurred in the study area. A correlation analysis indicated that landslides caused the pandas to migrate, and the core landslides within 1 km2 had greater influence on panda migration. These core landslides primarily occurred in mid-altitude regionscharacterized by high slopes, old geological ages, large areas and large rock mass volumes. The habitat suitability assessment results for the Wolong Natural Reserve had better prediction performance(80.9%) and demonstrated that 14.5%, 15.9%, 20.5%, 47.6% and 1.5% of the study area can be classified as very high, high, moderate, low and very low giant panda suitability areas, respectively. This study can be used to inform panda and panda habitat research, management and protection during post-quake reconstruction and recovery periods in China.  相似文献   

19.
The 5.12 Earthquake in 2008 and 8.14 Debris Flow in 2010 resulted in large-scale landslides that disturbed vast areas of vegetation in the Hongchun Gully, Wenchuan County, China. To define the specific characteristics of vegetation restoration during natural recovery after catastrophic events,vegetation species composition and interspecific associations were investigated on this typical landslide. Field survey data selected from a total of 51 sample plots belonged to seven belt transects and were analysed by Schluter's variance ratio, pearson's chi-squared test, Spearman's correlation coefficients and ecological species groups. Plant communities on the landslide consisted of 78 species, 65 genera and52 families. Of the total of 78 species, 25 are identified as dominant species, among which Camptotheca acuminate, Toxicodendron vernicifluum, Coriaria nepalensis, Robinia pseudoacacia, Buddleja alternifolia, Anemone vitifolia and Nephrolepis auriculata play a constructive role during the natural afforestation. Moreover, according to environmental and ecological factors, these 25 dominant species could be divided into four ecological species groups.This study found that even though the landslide had frequently suffered from interference due to heavy rain, the vegetation succession processes are ongoing,and it is now at a shrub–herb community succession stage, which indicates that vegetation can naturally recover in the denuded sites. This study provides a useful insight into the ecological interactions and interdependence between plant species during the natural recovery of vegetation and provides valuable information on vegetation recovery modelling in the landslide area.  相似文献   

20.
This study aims to provide a predictive vegetation mapping approach based on the spectral data, DEM and Generalized Additive Models (GAMs). GAMs were used as a prediction tool to describe the relationship between vegetation and environmental variables, as well as spectral variables. Based on the fitted GAMs model, probability map of species occurrence was generated and then vegetation type of each grid was defined according to the probability of species occurrence. Deviance analysis was employed to test the goodness of curve fitting and drop contribution calculation was used to evaluate the contribution of each predictor in the fitted GAMs models. Area under curve (AUC) of Receiver Operating Characteristic (ROC) curve was employed to assess the results maps of probability. The results showed that: 1) AUC values of the fitted GAMs models are very high which proves that integrating spectral data and environmental variables based on the GAMs is a feasible way to map the vegetation. 2) Prediction accuracy varies with plant community, and community with dense cover is better predicted than sparse plant community. 3) Both spectral variables and environmental variables play an important role in mapping the vegetation. However, the contribution of the same predictor in the GAMs models for different plant communities is different. 4) Insufficient resolution of spectral data, environmental data and confounding effects of land use and other variables which are not closely related to the environmental conditions are the major causes of imprecision.  相似文献   

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