Habitat fragmentation has been a research hotspot of biodiversity,and an important "bottleneck" restricting biodiversity.Habitat fragmentation can cause species loss and affect the process of immigration and...Habitat fragmentation has been a research hotspot of biodiversity,and an important "bottleneck" restricting biodiversity.Habitat fragmentation can cause species loss and affect the process of immigration and colonization by decreasing habitat size and increasing isolation degree among populations,thereby affecting species diversity of animals and plants.This paper elaborated the concept and main theory of habitat fragmentation and the influence of habitat fragmentation on species diversity of animals and plants,and suggested that studies on the effects of habitat fragmentation on species diversity at multi-trophic levels and larger scales should be strengthened.展开更多
Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans...Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans,especially in the agricultural economy.It causes insect outbreaks,the expansion of alien species,and disrupts biological management by rendering the habitat unsuitable for natural enemies in agriculture.Providing natural enemies with additional food is one method to improve the ecosystem and support them.In this study,we assumed that the ecosystem is separated into two patches and that predators can easily migrate from one patch to the next,while prey stays inside its patch's territory.We looked at the impact of offering more food to predators in a patchy environment using dynamical systems theory.The permanence,stability,and various bifurcations that occur in the system are studied using a rigorous mathematical analysis.The study looks at how predator's access to other food sources affects pest management.By adjusting the provided food's characteristic qualities,such as(nutritional)quality and quantity,one can limit and manage the pest in one or both patches,as well as eliminate predators from the ecosystem.This research reveals that providing predators with additional food(of specified quality and quantity)can help in controlling chaotic behavior in the system.The findings of the study are supported by numerical simulations.展开更多
A number of isolated islands of Leymus chinensis + herbosa community were investigated in fragmented habitat islands, by Braun-Blanquet field survey approach, in a degenerated meadow in the Songnen Plain, China in 20...A number of isolated islands of Leymus chinensis + herbosa community were investigated in fragmented habitat islands, by Braun-Blanquet field survey approach, in a degenerated meadow in the Songnen Plain, China in 2007. These islands were classified as large, medium, and small scales on the basis of the island area (100-1000m2, large island; 50-100m2, middle island; 10-50m2, small island). Each scale of the investigation involved eight islands. The responses ofβ-diversity patterns of plant taxon to the habitat fragmentation at local community and metacommunity levels were analyzed on different scales of 24 isolated islands. The results indicated that at the local community level, there were 57 species belonging to 20 families and 49 genera in large islands, 49 species belonging to 16 families and 40 genera in middle islands, and 27 species belonging to eight families and 23 genera in small islands, β-diversity indexes for species, genus and family in large, middle, and small islands varied greatly, and the highest value of the indexes was not noted in the largest island. However, the average of the data obtained at the three scales showed that across large islands, Whittaker indexes were low and Bray-Curtis similarity indexes were high, while across small islands, Whittaker indexes were high and Bray-Curtis similarity indexes were low. At the metacommunity level, Whittaker indexes for species and genus showed a great significantly negative double logarithmic correlation (p〈0.01) with the island area, whereas the Bray-Curtis indexes for species, genus and family showed a great significantly positive double logarithmic correlation (p〈0.01) with the island area. At both local community and metacommunity levels, tumovers of species and genus could respond more sensitively to spatial changes of plant diversity patterns than that of family. Hence, the species and the genus could be used for the analysis offl-diversity patterns of plant community.展开更多
Aims The pine rocklands of southern Florida are a fire-dependent forest associated with outcrops of limestone.Pine rockland plants have sev-eral adaptations to fire,and for many species,burning increases plant growth,...Aims The pine rocklands of southern Florida are a fire-dependent forest associated with outcrops of limestone.Pine rockland plants have sev-eral adaptations to fire,and for many species,burning increases plant growth,flowering and seedling establishment.The pine rockland forest has been reduced and fragmented in recent decades.Outside of Everglades National Park,only 2%of the original pine rocklands remain,and they are in the form of small fragments.Our objective is to investigate the effects of fragmentation and habitat quality on abun-dance and plant reproductive fitness of Angadenia berteroi(A.D.C.)Miers,a threatened species of the southern Florida pine rockland.Methods We estimated the density of plants using a stratified random sam-pling design,and reproductive fitness(in terms of percentage of plants with flowers and fruit)by walking transects in an array of habitat fragments of different sizes and degrees of isolation(distance to the nearest fragment)as well as in continuous habitat.Structural equation modeling(SEM)was employed to investigate how A.berteroi reproductive fitness was affected by fragmentation and habitat quality.Important Findings Habitat fragment size was correlated with the density of A.berteroi,but did not have a great impact on its reproductive success.However,habitat quality represented by litter depth and subcan-opy cover had strong negative effects on the reproductive fitness of A.berteroi,suggesting that increased light availability and low litter cover resulting from recent fires may favor reproduction.展开更多
Aims This study aimed to examine the changes in plant species richness,frequency and density along a habitat fragmentation gradient(with varied degrees of habitat fragmentation[DHFs])in a desertified grass-land of Hor...Aims This study aimed to examine the changes in plant species richness,frequency and density along a habitat fragmentation gradient(with varied degrees of habitat fragmentation[DHFs])in a desertified grass-land of Horqin Sandy Land,northeastern Inner Mongolia,China.Methods In this study,six landscape plots(500×500 m each)along a habi-tat fragmentation gradient were established.A new fragmentation index was formulated to study the effects of habitat fragmentation on biodiversity indices(species richness,frequency and density).Regression analyses(linear-or non-linear regression)were con-ducted to assess the changes in species richness,frequency and density along the habitat fragmentation gradient at plant commu-nity,functional group and species scales,respectively.Important Findings There was a non-linear relationship(following a quadratic function)between total species richness and the DHF.Total species richness reached its peak when the DHF was 0.2,beyond which species richness decreased along the fragmentation gradient.Plant func-tional groups showed their specific responses to habitat fragmenta-tion,and some non-linear relationships and thresholds existed.The relative richness of rare species also showed a non-linear response to habitat fragmentation,with the threshold being DHF=0.6.Species became rarer(both some common species and rare spe-cies)with the intensifying habitat fragmentation.Our study dem-onstrates the importance of the non-linear relationships and plant functional groups in exploring the effects of habitat fragmentation on biodiversity and implementing effective biological conservation in sand dunes.展开更多
A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species;some raise concern that biodiversity loss and its effects w...A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species;some raise concern that biodiversity loss and its effects will be exacerbated.The published literature on spatial dynamics(such as dispersal and metapopulation dynamics),habitat fragmentation and climate change requires synthesis and a conceptual framework to simplify thinking.We propose a framework that integrates how climate change affects spatial population dynamics and the effects of habitat fragmentation in terms of:(i)habitat quality,quantity and distribution;(ii)habitat connectivity;and(iii)the dynamics of habitat itself.We use the framework to categorize existing autecological studies and investigate how each is affected by anthropogenic climate change.It is clear that a changing climate produces changes in the geographic distribution of climatic conditions,and the amount and quality of habitat.The most thorough published studies show how such changes impact metapopulation persistence,source-sink dynamics,changes in species’geographic range and community composition.Climate-related changes in movement behavior and quantity,quality and distribution of habitat have also produced empirical changes in habitat connectivity for some species.An underexplored area is how habitat dynamics that are driven by climatic processes will affect species that live in dynamic habitats.We end our discussion by suggesting ways to improve current attempts to integrate climate change,spatial population dynamics and habitat fragmentation effects,and suggest distinct areas of study that might provide opportunities for more fully integrative work.展开更多
Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patches.The ROMPA hypothesis(ratio of optimal to marginal patch area)uniquely links vole population fluctu...Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patches.The ROMPA hypothesis(ratio of optimal to marginal patch area)uniquely links vole population fluctuations to the composition of the landscape.It states that as ROMPA decreases(fragmentation increases),vole population fluctuations will increase(including the tendency to display multi-annual cycles in abundance)because decreased proportions of optimal habitat result in greater population declines and longer recovery time after a harsh season.To date,only comparative observations in the field have supported the hypothesis.This paper reports the results of the first experimental test.I used prairie voles,Microtus ochrogaster,and mowed grassland to create model landscapes with 3 levels of ROMPA(high with 25%mowed,medium with 50%mowed and low with 75%mowed).As ROMPA decreased,distances between patches of favorable habitat(high cover)increased owing to a greater proportion of unfavorable(mowed)habitat.Results from the first year with intensive live trapping indicated that the preconditions for operation of the hypothesis existed(inversely density dependent emigration and,as ROMPA decreased,increased per capita mortality and decreased per capita movement between optimal patches).Nevertheless,contrary to the prediction of the hypothesis that populations in landscapes with high ROMPA should have the lowest variability,5 years of trapping indicated that variability was lowest with medium ROMPA.The design of field experiments may never be perfect,but these results indicate that the ROMPA hypothesis needs further rigorous testing.展开更多
The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered...The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered as the homogenous parts of the landscape. Also the metapopulation concept problem of the inert habitat heterogenity is considered quite seldom. These approaches have some weak points resulting from the assumption that the border between habitat patches and the metapopulation matrix is fairly sharp. This paper presents a resource-based concept of habitats, based on mathematical theory of point processes, which can be easily applied to analysing the problem of uneven distribution of resources. The basic assumption is that the random distribution of resources may be mathematically described as the realisation of a certain point process. According to our method, it is possible to calculate the expected quantities of available resources as well as the minimum area of habitat that includes the expected abundance of the resource. This approach may be very useful to understand some crucial phenomena in landscape ecology, such as the patch size effect and its connection to habitat loss and fragmentation.展开更多
Behavioral fragmentation of wildlife habitat is discussed. Using “buffer” module in ARC/INFO, behavioral fragmentation habitat of Red crowned crane, Saunders gull, Oriental white stork and Siberian white crane was ...Behavioral fragmentation of wildlife habitat is discussed. Using “buffer” module in ARC/INFO, behavioral fragmentation habitat of Red crowned crane, Saunders gull, Oriental white stork and Siberian white crane was calculated in the Shuangtai hekou National Reserve, Liaoning Province, China. The result showed that breeding Red crowned crane, Siberian white crane and breeding Saunders gull are very sensitive to fragmentation factors. Suitable habitat is so little for more than 2000 Saunders gull to breed. The reserve only has a capacity of 38 pairs for breeding Red crowed crane. Two key measures were made. First, dismantles all the abandoned oil wells and recovers the original ecosystem to decrease the fragmentation effect, directly benefit to breeding or migration of Red crowned crane and Oriental white stork. Second, recovers the Suaeda tidal mud flat from artificial shrimp and crab pond in the kernel zone of the reserve to enlarge the habitat area of Saunders gull and Siberian white crane.展开更多
The purpose of the present study was to examine the genetic variation in Salamandra infraimmaculata from different breeding site habitats using the Amplified Fragment Length Polymorphism (AFLP) method. The results of ...The purpose of the present study was to examine the genetic variation in Salamandra infraimmaculata from different breeding site habitats using the Amplified Fragment Length Polymorphism (AFLP) method. The results of the dendogram from a hierarchical cluster analysis show that the grouping of S. infraimmaculata as cluster 5 differs from all the other clusters, including the St1 (Tel-Dan stream) population, which was the most predictable. Five Haplogroups (Hg) were characterized. The mean number of alleles per locus in each population (Ne) ranged from 10.566 (Sp1) to 2.720 (Po6). An average estimated heterozygosity (He) by population ranged from 0.100 (Po6) to 0.186 (St1). Population St1, a permanent breeding site where water was available all year round, exhibited the highest level of polymorphism, while population Po6, from the ephemeral breeding site, exhibited the lowest level of polymorphism. Gene flow between clusters showed that clusters 3 and 4 are sources of migrants and also receive gene flow, while clusters 1 and 2 may be a source of migrants but may not receive much gene flow. A phylogenetic analysis, based on clustering using Nei’s genetic distance, demonstrated that the Tel-Dan population is located on a separate branch within its sub-population. The conclusion of the present study shows that the genetic divergence among isolated populations is not correlated to distance but is affected by the variation of habitats.展开更多
The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. Fr...The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. From June 2009 to September 2010 we conducted an investigation of 13 relatively isolated habitats or sites, selected from each of the 13 nature reserves in southwestern Guangxi, with the least amount of anthropological activity and the largest presence of the original vegetation, in order to study the distribution of birds on forest fragments. The distribution patterns of the birds and the factors which affect them were analyzed by using the 'BINMATNEST' software and the Spearman’s rank correlation analysis, to determine: 1) whether nested patterns of birds in the karst area of southwestern Guangxi exist or not and 2) which factors are correlated with the nested patterns and the effect of these factors on forming nested patterns. The results show that the birds had statistically significant nested patterns in the karst area and the specificity of the habitat of the birds had a significant effect on the nested patterns. We suggest possible reasons for these results, based on the characteristics of the seasonal tropical rain forests in the study area and on neutral theory. We also urgently recommend that close attention be paid to the protection of the diversity of the environment for birds in all fragmented habitats.展开更多
The dual impact of climate change and human activities has precipitated a sharp decline in primate biodiversity globally.China is home to the most diverse primate species in the Northern hemisphere,which face severe e...The dual impact of climate change and human activities has precipitated a sharp decline in primate biodiversity globally.China is home to the most diverse primate species in the Northern hemisphere,which face severe ecological threats due to the expansion of modern agriculture,extensive exploitation and consumption of natural resources,and excessive land development during its transition from an agricultural to a modern society.In response,China has implemented various ecological conservation measures,including habitat restoration and protection.These efforts have made substantial strides in biodiversity conservation,with certain regions witnessing an increase in primate populations.In the current study,we conducted a systematic review of historical documents and field research data related to Chinese primates,evaluating the endangered status of primate species in China.Despite improvements in the habitats of most primate species and some population growth,many species still face severe threats,including declining and small populations.Species such as the Myanmar snub-nosed monkey(Rhinopithecus strykeri),eastern black crested gibbon(Nomascus nasutus),and Hainan gibbon(N.hainanus)remain particularly vulnerable due to their limited distribution ranges and extremely small populations.Insufficient scientific data,fragmented information,and not enough studies in conservation biology further compound the challenges.Moreover,there is a notable lack of detailed population monitoring data for species such as the Bengal slow loris(Nycticebus bengalensis),pygmy slow loris(N.pygmaeus),Indochinese gray langur(Trachypithecus crepusculus),Shortridge’s langur(T.shortridgei),and capped langur(T.pileatus),which hinders the development of practical and targeted conservation management strategies.Therefore,for national biodiversity conservation,there is an urgent need for specialized primate surveys,enhancing habitat protection and restoration,and increasing focus on cross-border conservation strategies and regional cooperation.There is also a need to establish a comprehensive and systematic research database platform,conduct continuous and in-depth research in primate biology,and actively engage in the scientific assessment of ecotourism.Additionally,strengthening public awareness and education on wildlife conservation remains essential.Such integrated and systematic efforts will provide scientific support for the current and future conservation and management of primate species in China.展开更多
Hydropower development has become an important driver of habitat loss and fragmentation across lowland tropical forests.Despite ample evidence on the detrimental effects of insular habitat fragmentation on biodiversit...Hydropower development has become an important driver of habitat loss and fragmentation across lowland tropical forests.Despite ample evidence on the detrimental effects of insular habitat fragmentation on biodiversity,invertebrate taxa,that may be critical to ecosystem functioning,have been overlooked.We assessed the assemblage-level responses of social wasps to forest insularization induced by the Balbina Hydroelectric Dam in Central Brazilian Amazonia.Employing Malaise trapping,we captured wasps on 27 forest islands and three continuous forests.We constructed Generalized Linear Models and employed a model selection approach to examine the impact of local variables(fire severity(FIRE)and basal area of pioneer tree species(PIONEER))and landscape-scale variables(amount of habitat(COVER))on patterns of species richness,composition,and body size of wasps.A total of 374 individuals(29 species)were collected across all sampling sites.COVER was the main predictor of species richness,while PIONEER was the only variable that explained variation in community composition,with a negative effect on body size.Our results add evidence to the pervasive impacts of large hydroelectric dams on tropical forest biodiversity,and suggest that social wasps,among other invertebrates,can be used as bioindicators in infrastructure development projects.展开更多
The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grou...The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grouse habitats. We used SPOT (XS-sensor) satellite imagery to discriminate between open land and conifer or broadleaf forests. The area analyzed is about 120000 ha in size and includes the Lianhuashan Nature Reserve and the Yeliguan Forestry Park. We identiifed 4111 ha of mature coniferous forests in 229 patches (maximum 332 ha, mean 18 ha) as the habitat used by Chinese Grouse throughout the year. We examined 31 forest islands of different sizes and degrees of isolation for the presence of Chinese Grouse. We used generalized linear models (GLM) with binomial error structure and logit link function to estimate the probability of Chinese Grouse occupancy in a forest fragment. Habitat patch size (hs) and distance to the next occupied fragment (doc) were used as predictor variables, important for occupancy. Small habitat islands were disproportionately less likely to be occupied than large, nearby habitats. There was a clear speciifc habitat size of about 40 ha, above which habitat fragments were occupied more often. Suitable habitat fragments isolated by more than 2 km appeared to be inaccessible to Chinese Grouse. The results have been used in reforestation projects to establish linking corridors in the study area.展开更多
为探究生境面积大小对Janzen-Connell (JC)效应中密度和距离制约的影响以及驱动机制,为生境破碎化背景下植物多样性的维持机制提供科学依据,本研究在Web of Science数据库中收集并筛选出1970-2019年全球50个森林地点作为数据基础,采用...为探究生境面积大小对Janzen-Connell (JC)效应中密度和距离制约的影响以及驱动机制,为生境破碎化背景下植物多样性的维持机制提供科学依据,本研究在Web of Science数据库中收集并筛选出1970-2019年全球50个森林地点作为数据基础,采用荟萃分析法分析密度和距离制约实验中不同类型驱动者的效应值大小,并采用分段回归和非分段回归分别模拟分析密度和距离制约效应值与生境面积的关系。结果表明,在67项研究的161项实验中,病原菌和无脊椎动物的效应值大小在距离制约实验中显著小于0(存在JC效应),而在密度制约实验中不显著。相反地,脊椎动物的效应值大小仅在密度制约实验中显著小于0。虽然只有距离制约效应值随生境面积的减少呈先增大后减小的趋势,但密度制约趋势线的拟合转折点在距离制约之前,表明生境面积减少会先影响密度制约。本研究阐明了密度和距离制约的主要驱动者分别是密度型驱动者(脊椎动物)和距离型驱动者(病原菌和无脊椎动物),而密度制约比距离制约对生境面积的减少有更为敏感的表现,可能是这两种驱动者对生境面积的需求不同所导致的。因此,在不同生境面积的片段中关注不同类型的驱动者有利于生物多样性的维持。展开更多
Habitat loss and fragmentation are mainly associated with population decrease of endangered species and biodiversity loss. The habitat suitability maps of red-crowned crane (Grusjaponensis) in 1992, 1999 and 2006 we...Habitat loss and fragmentation are mainly associated with population decrease of endangered species and biodiversity loss. The habitat suitability maps of red-crowned crane (Grusjaponensis) in 1992, 1999 and 2006 were produced by using Ecological Niche Suitability Model (ENSM) in Yellow River Delta Nature Reserve (118°33′-119°20′E longitude, 37°35′-38°12′N latitude), Shandong Province, China. Based on the habitat suitability maps, the causation and change law of habitat loss and fragmentation of red-crowned crane were analyzed by selecting a series of landscape pattern indices. Results showed that due to scarcities of fresh water sources, habitat suitability of red-crowned crane in 1999 was inferior to that in 1992 and 2006 no matter whether human disturbances existed or not. Besides, human disturbance activities, especially road disturbances, increased rapidly during the period of 1992-2006. This worsened the habitat loss and frag- mentation of red-crowned crane, and led to degrading habitat suitability of red-crowned crane in 2006, compared with that in 1992. In conclusion, fresh water sources and human disturbance activities are the two main factors that drive the habitat suitability change of red-crowned crane.展开更多
文摘Habitat fragmentation has been a research hotspot of biodiversity,and an important "bottleneck" restricting biodiversity.Habitat fragmentation can cause species loss and affect the process of immigration and colonization by decreasing habitat size and increasing isolation degree among populations,thereby affecting species diversity of animals and plants.This paper elaborated the concept and main theory of habitat fragmentation and the influence of habitat fragmentation on species diversity of animals and plants,and suggested that studies on the effects of habitat fragmentation on species diversity at multi-trophic levels and larger scales should be strengthened.
文摘Due to human-caused deforestation,global warming,and other environmental factors,habitat fragmentation became widespread.This fragmentation has a variety of detrimental repercussions for many species as well as humans,especially in the agricultural economy.It causes insect outbreaks,the expansion of alien species,and disrupts biological management by rendering the habitat unsuitable for natural enemies in agriculture.Providing natural enemies with additional food is one method to improve the ecosystem and support them.In this study,we assumed that the ecosystem is separated into two patches and that predators can easily migrate from one patch to the next,while prey stays inside its patch's territory.We looked at the impact of offering more food to predators in a patchy environment using dynamical systems theory.The permanence,stability,and various bifurcations that occur in the system are studied using a rigorous mathematical analysis.The study looks at how predator's access to other food sources affects pest management.By adjusting the provided food's characteristic qualities,such as(nutritional)quality and quantity,one can limit and manage the pest in one or both patches,as well as eliminate predators from the ecosystem.This research reveals that providing predators with additional food(of specified quality and quantity)can help in controlling chaotic behavior in the system.The findings of the study are supported by numerical simulations.
基金Under the auspices of Major State Basic Research Development Program of China (973 Progrom) (No 2007CB106801)National Key Technology R&D Program of China (No 2006BAD16B06)National Natural Science Foundation of China (No 30470180,30770397)
文摘A number of isolated islands of Leymus chinensis + herbosa community were investigated in fragmented habitat islands, by Braun-Blanquet field survey approach, in a degenerated meadow in the Songnen Plain, China in 2007. These islands were classified as large, medium, and small scales on the basis of the island area (100-1000m2, large island; 50-100m2, middle island; 10-50m2, small island). Each scale of the investigation involved eight islands. The responses ofβ-diversity patterns of plant taxon to the habitat fragmentation at local community and metacommunity levels were analyzed on different scales of 24 isolated islands. The results indicated that at the local community level, there were 57 species belonging to 20 families and 49 genera in large islands, 49 species belonging to 16 families and 40 genera in middle islands, and 27 species belonging to eight families and 23 genera in small islands, β-diversity indexes for species, genus and family in large, middle, and small islands varied greatly, and the highest value of the indexes was not noted in the largest island. However, the average of the data obtained at the three scales showed that across large islands, Whittaker indexes were low and Bray-Curtis similarity indexes were high, while across small islands, Whittaker indexes were high and Bray-Curtis similarity indexes were low. At the metacommunity level, Whittaker indexes for species and genus showed a great significantly negative double logarithmic correlation (p〈0.01) with the island area, whereas the Bray-Curtis indexes for species, genus and family showed a great significantly positive double logarithmic correlation (p〈0.01) with the island area. At both local community and metacommunity levels, tumovers of species and genus could respond more sensitively to spatial changes of plant diversity patterns than that of family. Hence, the species and the genus could be used for the analysis offl-diversity patterns of plant community.
基金Funding was provided to Beyte Barrios by The Florida Native Plant Society(2008 Endowment Research Grant)FIU Kelly Scholarships(2008,2009,2012,2013)+1 种基金the Catherine H.Beattie Fellowship(2009)from The Garden Club of Americaa Florida International University Doctoral Evidence Acquisition Fellowship(2014).Collections were made under permit#0080 from Natural Areas Management,Miami-Dade County and Everglades National Park Scientific research and collection permit#EVER-2013-SCI-0030.This is contribution#316 to the Tropical Biology Program and#785 to the Southeast Environmental Research Center(SERC)at Florida International University.
文摘Aims The pine rocklands of southern Florida are a fire-dependent forest associated with outcrops of limestone.Pine rockland plants have sev-eral adaptations to fire,and for many species,burning increases plant growth,flowering and seedling establishment.The pine rockland forest has been reduced and fragmented in recent decades.Outside of Everglades National Park,only 2%of the original pine rocklands remain,and they are in the form of small fragments.Our objective is to investigate the effects of fragmentation and habitat quality on abun-dance and plant reproductive fitness of Angadenia berteroi(A.D.C.)Miers,a threatened species of the southern Florida pine rockland.Methods We estimated the density of plants using a stratified random sam-pling design,and reproductive fitness(in terms of percentage of plants with flowers and fruit)by walking transects in an array of habitat fragments of different sizes and degrees of isolation(distance to the nearest fragment)as well as in continuous habitat.Structural equation modeling(SEM)was employed to investigate how A.berteroi reproductive fitness was affected by fragmentation and habitat quality.Important Findings Habitat fragment size was correlated with the density of A.berteroi,but did not have a great impact on its reproductive success.However,habitat quality represented by litter depth and subcan-opy cover had strong negative effects on the reproductive fitness of A.berteroi,suggesting that increased light availability and low litter cover resulting from recent fires may favor reproduction.
基金This study was financially supported by National Natural Science Foundation of China(31600443,41501573)。
文摘Aims This study aimed to examine the changes in plant species richness,frequency and density along a habitat fragmentation gradient(with varied degrees of habitat fragmentation[DHFs])in a desertified grass-land of Horqin Sandy Land,northeastern Inner Mongolia,China.Methods In this study,six landscape plots(500×500 m each)along a habi-tat fragmentation gradient were established.A new fragmentation index was formulated to study the effects of habitat fragmentation on biodiversity indices(species richness,frequency and density).Regression analyses(linear-or non-linear regression)were con-ducted to assess the changes in species richness,frequency and density along the habitat fragmentation gradient at plant commu-nity,functional group and species scales,respectively.Important Findings There was a non-linear relationship(following a quadratic function)between total species richness and the DHF.Total species richness reached its peak when the DHF was 0.2,beyond which species richness decreased along the fragmentation gradient.Plant func-tional groups showed their specific responses to habitat fragmenta-tion,and some non-linear relationships and thresholds existed.The relative richness of rare species also showed a non-linear response to habitat fragmentation,with the threshold being DHF=0.6.Species became rarer(both some common species and rare spe-cies)with the intensifying habitat fragmentation.Our study dem-onstrates the importance of the non-linear relationships and plant functional groups in exploring the effects of habitat fragmentation on biodiversity and implementing effective biological conservation in sand dunes.
文摘A growing number of studies have looked at how climate change alters the effects of habitat fragmentation and degradation on both single and multiple species;some raise concern that biodiversity loss and its effects will be exacerbated.The published literature on spatial dynamics(such as dispersal and metapopulation dynamics),habitat fragmentation and climate change requires synthesis and a conceptual framework to simplify thinking.We propose a framework that integrates how climate change affects spatial population dynamics and the effects of habitat fragmentation in terms of:(i)habitat quality,quantity and distribution;(ii)habitat connectivity;and(iii)the dynamics of habitat itself.We use the framework to categorize existing autecological studies and investigate how each is affected by anthropogenic climate change.It is clear that a changing climate produces changes in the geographic distribution of climatic conditions,and the amount and quality of habitat.The most thorough published studies show how such changes impact metapopulation persistence,source-sink dynamics,changes in species’geographic range and community composition.Climate-related changes in movement behavior and quantity,quality and distribution of habitat have also produced empirical changes in habitat connectivity for some species.An underexplored area is how habitat dynamics that are driven by climatic processes will affect species that live in dynamic habitats.We end our discussion by suggesting ways to improve current attempts to integrate climate change,spatial population dynamics and habitat fragmentation effects,and suggest distinct areas of study that might provide opportunities for more fully integrative work.
文摘Increased habitat fragmentation leads to smaller size of habitat patches and to greater distance between patches.The ROMPA hypothesis(ratio of optimal to marginal patch area)uniquely links vole population fluctuations to the composition of the landscape.It states that as ROMPA decreases(fragmentation increases),vole population fluctuations will increase(including the tendency to display multi-annual cycles in abundance)because decreased proportions of optimal habitat result in greater population declines and longer recovery time after a harsh season.To date,only comparative observations in the field have supported the hypothesis.This paper reports the results of the first experimental test.I used prairie voles,Microtus ochrogaster,and mowed grassland to create model landscapes with 3 levels of ROMPA(high with 25%mowed,medium with 50%mowed and low with 75%mowed).As ROMPA decreased,distances between patches of favorable habitat(high cover)increased owing to a greater proportion of unfavorable(mowed)habitat.Results from the first year with intensive live trapping indicated that the preconditions for operation of the hypothesis existed(inversely density dependent emigration and,as ROMPA decreased,increased per capita mortality and decreased per capita movement between optimal patches).Nevertheless,contrary to the prediction of the hypothesis that populations in landscapes with high ROMPA should have the lowest variability,5 years of trapping indicated that variability was lowest with medium ROMPA.The design of field experiments may never be perfect,but these results indicate that the ROMPA hypothesis needs further rigorous testing.
基金funded by Institute of Nature Conservation PASpartly by a Polish State Committee for Scientific Research/National Science Centre grant No.N N304 325836.
文摘The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered as the homogenous parts of the landscape. Also the metapopulation concept problem of the inert habitat heterogenity is considered quite seldom. These approaches have some weak points resulting from the assumption that the border between habitat patches and the metapopulation matrix is fairly sharp. This paper presents a resource-based concept of habitats, based on mathematical theory of point processes, which can be easily applied to analysing the problem of uneven distribution of resources. The basic assumption is that the random distribution of resources may be mathematically described as the realisation of a certain point process. According to our method, it is possible to calculate the expected quantities of available resources as well as the minimum area of habitat that includes the expected abundance of the resource. This approach may be very useful to understand some crucial phenomena in landscape ecology, such as the patch size effect and its connection to habitat loss and fragmentation.
文摘Behavioral fragmentation of wildlife habitat is discussed. Using “buffer” module in ARC/INFO, behavioral fragmentation habitat of Red crowned crane, Saunders gull, Oriental white stork and Siberian white crane was calculated in the Shuangtai hekou National Reserve, Liaoning Province, China. The result showed that breeding Red crowned crane, Siberian white crane and breeding Saunders gull are very sensitive to fragmentation factors. Suitable habitat is so little for more than 2000 Saunders gull to breed. The reserve only has a capacity of 38 pairs for breeding Red crowed crane. Two key measures were made. First, dismantles all the abandoned oil wells and recovers the original ecosystem to decrease the fragmentation effect, directly benefit to breeding or migration of Red crowned crane and Oriental white stork. Second, recovers the Suaeda tidal mud flat from artificial shrimp and crab pond in the kernel zone of the reserve to enlarge the habitat area of Saunders gull and Siberian white crane.
文摘The purpose of the present study was to examine the genetic variation in Salamandra infraimmaculata from different breeding site habitats using the Amplified Fragment Length Polymorphism (AFLP) method. The results of the dendogram from a hierarchical cluster analysis show that the grouping of S. infraimmaculata as cluster 5 differs from all the other clusters, including the St1 (Tel-Dan stream) population, which was the most predictable. Five Haplogroups (Hg) were characterized. The mean number of alleles per locus in each population (Ne) ranged from 10.566 (Sp1) to 2.720 (Po6). An average estimated heterozygosity (He) by population ranged from 0.100 (Po6) to 0.186 (St1). Population St1, a permanent breeding site where water was available all year round, exhibited the highest level of polymorphism, while population Po6, from the ephemeral breeding site, exhibited the lowest level of polymorphism. Gene flow between clusters showed that clusters 3 and 4 are sources of migrants and also receive gene flow, while clusters 1 and 2 may be a source of migrants but may not receive much gene flow. A phylogenetic analysis, based on clustering using Nei’s genetic distance, demonstrated that the Tel-Dan population is located on a separate branch within its sub-population. The conclusion of the present study shows that the genetic divergence among isolated populations is not correlated to distance but is affected by the variation of habitats.
基金financed by the National Nature Science Foundation of China (Grant Nos. 30970381,31172123)
文摘The limestone region in southwestern Guangxi contains the most typical karst landforms in the world. Due to their destruction, the original forests mainly survive in nature reserves in the form of fragmented areas. From June 2009 to September 2010 we conducted an investigation of 13 relatively isolated habitats or sites, selected from each of the 13 nature reserves in southwestern Guangxi, with the least amount of anthropological activity and the largest presence of the original vegetation, in order to study the distribution of birds on forest fragments. The distribution patterns of the birds and the factors which affect them were analyzed by using the 'BINMATNEST' software and the Spearman’s rank correlation analysis, to determine: 1) whether nested patterns of birds in the karst area of southwestern Guangxi exist or not and 2) which factors are correlated with the nested patterns and the effect of these factors on forming nested patterns. The results show that the birds had statistically significant nested patterns in the karst area and the specificity of the habitat of the birds had a significant effect on the nested patterns. We suggest possible reasons for these results, based on the characteristics of the seasonal tropical rain forests in the study area and on neutral theory. We also urgently recommend that close attention be paid to the protection of the diversity of the environment for birds in all fragmented habitats.
基金supported by the National Natural Science Foundation of China(32371563)and Strategic Priority Research Program of the Chinese Academy of Sciences(XDB31020302)。
文摘The dual impact of climate change and human activities has precipitated a sharp decline in primate biodiversity globally.China is home to the most diverse primate species in the Northern hemisphere,which face severe ecological threats due to the expansion of modern agriculture,extensive exploitation and consumption of natural resources,and excessive land development during its transition from an agricultural to a modern society.In response,China has implemented various ecological conservation measures,including habitat restoration and protection.These efforts have made substantial strides in biodiversity conservation,with certain regions witnessing an increase in primate populations.In the current study,we conducted a systematic review of historical documents and field research data related to Chinese primates,evaluating the endangered status of primate species in China.Despite improvements in the habitats of most primate species and some population growth,many species still face severe threats,including declining and small populations.Species such as the Myanmar snub-nosed monkey(Rhinopithecus strykeri),eastern black crested gibbon(Nomascus nasutus),and Hainan gibbon(N.hainanus)remain particularly vulnerable due to their limited distribution ranges and extremely small populations.Insufficient scientific data,fragmented information,and not enough studies in conservation biology further compound the challenges.Moreover,there is a notable lack of detailed population monitoring data for species such as the Bengal slow loris(Nycticebus bengalensis),pygmy slow loris(N.pygmaeus),Indochinese gray langur(Trachypithecus crepusculus),Shortridge’s langur(T.shortridgei),and capped langur(T.pileatus),which hinders the development of practical and targeted conservation management strategies.Therefore,for national biodiversity conservation,there is an urgent need for specialized primate surveys,enhancing habitat protection and restoration,and increasing focus on cross-border conservation strategies and regional cooperation.There is also a need to establish a comprehensive and systematic research database platform,conduct continuous and in-depth research in primate biology,and actively engage in the scientific assessment of ecotourism.Additionally,strengthening public awareness and education on wildlife conservation remains essential.Such integrated and systematic efforts will provide scientific support for the current and future conservation and management of primate species in China.
基金supported by a NERC grant to C.A.P.(NE/J01401X/1)a Science Without Borders postdoctoral fellowship awarded to D.S.(CNPq grant 246975/2012-1)+1 种基金M.B.received a productivity grant from CNPq(304189/2022-7)supported by the inaugural Frontiers Planet Prize。
文摘Hydropower development has become an important driver of habitat loss and fragmentation across lowland tropical forests.Despite ample evidence on the detrimental effects of insular habitat fragmentation on biodiversity,invertebrate taxa,that may be critical to ecosystem functioning,have been overlooked.We assessed the assemblage-level responses of social wasps to forest insularization induced by the Balbina Hydroelectric Dam in Central Brazilian Amazonia.Employing Malaise trapping,we captured wasps on 27 forest islands and three continuous forests.We constructed Generalized Linear Models and employed a model selection approach to examine the impact of local variables(fire severity(FIRE)and basal area of pioneer tree species(PIONEER))and landscape-scale variables(amount of habitat(COVER))on patterns of species richness,composition,and body size of wasps.A total of 374 individuals(29 species)were collected across all sampling sites.COVER was the main predictor of species richness,while PIONEER was the only variable that explained variation in community composition,with a negative effect on body size.Our results add evidence to the pervasive impacts of large hydroelectric dams on tropical forest biodiversity,and suggest that social wasps,among other invertebrates,can be used as bioindicators in infrastructure development projects.
基金supported by the National Natural Science Foundation of China(Grant No.31270468,30620130110)
文摘The Chinese Grouse (Tetrastes sewerzowi) is a rare, endemic bird in China, inhabiting conifer-dominated mountain forests. Both the natural fragmentation and heavy cutting of mature forests have resulted in patchy grouse habitats. We used SPOT (XS-sensor) satellite imagery to discriminate between open land and conifer or broadleaf forests. The area analyzed is about 120000 ha in size and includes the Lianhuashan Nature Reserve and the Yeliguan Forestry Park. We identiifed 4111 ha of mature coniferous forests in 229 patches (maximum 332 ha, mean 18 ha) as the habitat used by Chinese Grouse throughout the year. We examined 31 forest islands of different sizes and degrees of isolation for the presence of Chinese Grouse. We used generalized linear models (GLM) with binomial error structure and logit link function to estimate the probability of Chinese Grouse occupancy in a forest fragment. Habitat patch size (hs) and distance to the next occupied fragment (doc) were used as predictor variables, important for occupancy. Small habitat islands were disproportionately less likely to be occupied than large, nearby habitats. There was a clear speciifc habitat size of about 40 ha, above which habitat fragments were occupied more often. Suitable habitat fragments isolated by more than 2 km appeared to be inaccessible to Chinese Grouse. The results have been used in reforestation projects to establish linking corridors in the study area.
文摘为探究生境面积大小对Janzen-Connell (JC)效应中密度和距离制约的影响以及驱动机制,为生境破碎化背景下植物多样性的维持机制提供科学依据,本研究在Web of Science数据库中收集并筛选出1970-2019年全球50个森林地点作为数据基础,采用荟萃分析法分析密度和距离制约实验中不同类型驱动者的效应值大小,并采用分段回归和非分段回归分别模拟分析密度和距离制约效应值与生境面积的关系。结果表明,在67项研究的161项实验中,病原菌和无脊椎动物的效应值大小在距离制约实验中显著小于0(存在JC效应),而在密度制约实验中不显著。相反地,脊椎动物的效应值大小仅在密度制约实验中显著小于0。虽然只有距离制约效应值随生境面积的减少呈先增大后减小的趋势,但密度制约趋势线的拟合转折点在距离制约之前,表明生境面积减少会先影响密度制约。本研究阐明了密度和距离制约的主要驱动者分别是密度型驱动者(脊椎动物)和距离型驱动者(病原菌和无脊椎动物),而密度制约比距离制约对生境面积的减少有更为敏感的表现,可能是这两种驱动者对生境面积的需求不同所导致的。因此,在不同生境面积的片段中关注不同类型的驱动者有利于生物多样性的维持。
基金the research was supported by National Natural Science Foundation (No. 40771172)Knowledge innovation project of the Chinese Academy of Sciences (No. kzcx2-yw-308)
文摘Habitat loss and fragmentation are mainly associated with population decrease of endangered species and biodiversity loss. The habitat suitability maps of red-crowned crane (Grusjaponensis) in 1992, 1999 and 2006 were produced by using Ecological Niche Suitability Model (ENSM) in Yellow River Delta Nature Reserve (118°33′-119°20′E longitude, 37°35′-38°12′N latitude), Shandong Province, China. Based on the habitat suitability maps, the causation and change law of habitat loss and fragmentation of red-crowned crane were analyzed by selecting a series of landscape pattern indices. Results showed that due to scarcities of fresh water sources, habitat suitability of red-crowned crane in 1999 was inferior to that in 1992 and 2006 no matter whether human disturbances existed or not. Besides, human disturbance activities, especially road disturbances, increased rapidly during the period of 1992-2006. This worsened the habitat loss and frag- mentation of red-crowned crane, and led to degrading habitat suitability of red-crowned crane in 2006, compared with that in 1992. In conclusion, fresh water sources and human disturbance activities are the two main factors that drive the habitat suitability change of red-crowned crane.