The present study assesses anthropogenic disturbances and their impacts on the vegetation in Western Himalaya,India on the basis of various disturbance parameters such as density,Total Basal Cover(TBC) of cut stumps,l...The present study assesses anthropogenic disturbances and their impacts on the vegetation in Western Himalaya,India on the basis of various disturbance parameters such as density,Total Basal Cover(TBC) of cut stumps,lopping percentage and grazing intensities.On the basis of canopy cover and frequency of disturbances(%),the studied forests were divided into highly disturbed(HD),moderately disturbed(MD) and least disturbed(LD) categories.The HD forests had the lowest canopy cover,lowest density and lowest TBC and the LD had the highest canopy cover,highest density and highest TBC.The MD forests occupied the intermediate position with respect to these parameters.Species richness was least in HD forests,highest in one of the MD forests while LD forest occupied an intermediate position.The percentage of regenerating species was lowest(54%) in HD and highest(72%) in MD.The density of seedlings and saplings was higher in one of the MD forests as compared to HD and LD.We concluded that the moderate disturbances do not affect the vegetation adversely;however the increased degree of disturbance causes loss in plant diversity;affects regeneration and changes community characteristics.Construction of hydroelectric projects at various places in the study area was found to be one of the most important sources of anthropogenic disturbances in addition to the routine anthropogenic disturbances like grazing,fuelwood collection and fodder extraction.If all proposed dams in the Indian Himalaya are constructed combined with weak national environmental impact assessment and implementation,it will result in a significant loss of species.Therefore,various agents of disturbances should be evaluated in cumulative manner and any developmental activities such as hydropower projects,which trigger various natural and anthropogenic disturbances,should be combined with proper cumulative environmental impact assessment and effective implementation to minimise the anticipated loss of vegetation.展开更多
Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effe...Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effects of these factors within the Lake Baringo woodland ecosystem. Data was collected from 60 plots of 20 m × 20 m systematically distributed in four A. senegal-dominated populations within the Lake Baringo woodland. Sample populations spanned a degradation gradient measured by a population disturbance index (PDI). Trees were measured for diameter at breast height (DBH) and categorized by growth stages: seedling, sapling and adult tree. Higher seedling and sapling densities were recorded in lightly than heavily disturbed populations, but only sapling density was significantly different between the two disturbance levels (P = 0.02). Lightly disturbed populations revealed a reversed J-shape size-class distribution (SCD) indicative of stable structure unlike the heavily disturbed populations. The quotient and permutation indices indicated unstable populations with episodic recruitment and mortality. Our study reveals that natural regeneration and population structure of A. senegal were affected majorly by selective harvesting and heavy browsing. Suitable management strategies to control livestock grazing and illegal tree harvesting within the woodland is required to promote conservation of the species genetic resources展开更多
The diversity of Planctomycetes and related bacteria in 3 types of freshwater wetlands with different anthropogenic disturbances were investigated by cloning and sequencing PCR-amplified partial 16S rRNA genes. Three ...The diversity of Planctomycetes and related bacteria in 3 types of freshwater wetlands with different anthropogenic disturbances were investigated by cloning and sequencing PCR-amplified partial 16S rRNA genes. Three clone libraries were constructed using 16S rRNA-targeted forward PCR primer specific for Planctomycetales and general bacterial reverse primer. Phylogenetic analysis of the 16S rRNA gene sequences defined 95 operational taxonomic units (OTUs) with 163 sequences. The clone libraries covered a wide microbial diversity of Proteobacteria and the Planctomycetes-Verrucomicrobia-Chlamydiales (PVC) superphylum. The majority of the OTUs were related to the phylum of Planctomycetes (33 OTUs), Proteobacteria (22 OTUs) and Verrucomicrobia (22 OTUs). Four known genera from the Planctomycetes phylum were all detected. The genus Pirellula (18 OTUs) dominated the Planctomycetes community, but different patterns of distribution were observed in the wetlands. The littoral wetlands of Baiyangdian Lake with the least anthropogenic disturbances covered more species and showed the highest biodiversity. However, the Jiaxing paddy fields with the highest anthropogenic disturbances showed a higher biodiversity than that in the riparian wetlands of the North Canal. Bacteria distantly related to anammox bacteria were also detected with a small proportion (4 OTUs). It showed that wetlands hold a great biodiversity of phyla Planctomycetes and related bacteria; furthermore, there is ample opportunity to discover novel phylotypes of Planctomycetes in the wetland ecosystems.展开更多
Almost three-fourths of forests are experiencing anthropogenic disturbances globally, and more than two-thirds of the forests in Nepal receive different types of disturbances. In community forests(CFs), local communit...Almost three-fourths of forests are experiencing anthropogenic disturbances globally, and more than two-thirds of the forests in Nepal receive different types of disturbances. In community forests(CFs), local communities are dependent on the ecosystem services provided by the forests for various aspects of their livelihoods, which disturb the forests’ natural conditions and ecosystem functioning in a variety of ways. This study tested the major disturbance factors that had influential roles on plant species diversity, recruitment(seedlings and saplings), biomass, soil organic carbon(SOC) and total carbon density in two community-managed forests in the Mid-hills of Nepal. The stump number, cut-off seedlings and saplings, lopping, dropping, and grazing/trampling were used as measures of the major anthropogenic disturbances. The necessary data were collected from 89 randomly selected sample plots, each with an area of 250 m2. The responses to anthropogenic disturbances were analyzed using Generalized Linear Models(GLM). The results showed that forest lopping was the most significant anthropogenic disturbance for biomass and total carbon density balance. A higher degree of lopping in the forests resulted in a lowering of the forests’ carbon stock in the study area. SOC showed no significant response to any of the tested anthropogenic disturbances. Woody species richness and number of saplings increased with an increasing number of stumps, which signifies that intermediate disturbance was beneficial. However, a higher intensity of lopping reduced the sapling density. Grazing/trampling was the most significant disturbance for inhibiting seedling growth. Areas in the forests with a higher intensity of trampling showed lower numbers of seedlings and saplings. These results will be a guide for managing anthropogenic disturbances in multiple-use forests in Nepal, as well as those in similar socio-economic environments worldwide.展开更多
Aims The aims of this study were to assess how functional diversity(FD)and functional redundancy respond to subalpine meadow ecosystem degradation under anthropogenic disturbance and how species contribute to function...Aims The aims of this study were to assess how functional diversity(FD)and functional redundancy respond to subalpine meadow ecosystem degradation under anthropogenic disturbance and how species contribute to functional redundancy along the disturbance gradient.Methods The study was carried out in the subalpine meadow in Mount Jade Dragon,which is located at the southeastern edge of the Tibetan Plateau.Four disturbance intensities[no disturbance(ND),weak disturbance(WD),moderate disturbance(MD)and severe disturbance(SD)]were identified.Species richness,soil properties and five key plant functional traits were assessed along the disturbance gradient.Simpson’s diversity index,FD based on the Rao algorithm,functional redundancy,community-weighted mean of each functional trait and species-level functional redundancy were determined.Important Findings Unimodal change pattern of FD and functional redundancy along the disturbance gradient were found in the present study,with their maximum in MD and WD,respectively.Species diversity showed a decreasing trend with increasing disturbance intensity.As disturbance intensified,species with traits related to conservative growth strategies,such as low specific leaf area(SLA)and high leaf dry matter content(LDMC),decreased,whereas species with resource acquisitive strategies,such as small plant,high SLA and low LDMC,increased in the community.At the species level,species showed species-specific roles in functional redundancy.Notably,some species were important in the community in terms of their unique function.For instance,Ligularia dictyoneura in ND and Potentilla delavayi in MD and SD.展开更多
The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） Wha...The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） What is the ecological niche of the different epiphytic orchid species？ （2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （PCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.展开更多
This paper investigated the information about Ice sheet melt and Ozone hole variations during three solar cycles. After performing the inquiry on the data, the final results pointed out that both phenomena varying acc...This paper investigated the information about Ice sheet melt and Ozone hole variations during three solar cycles. After performing the inquiry on the data, the final results pointed out that both phenomena varying accord with Earth’s seasonality. The sea melt extension depends on the season and if the ocean waters are warmer around the polar caps. We checked the suggestion that anthropogenic perturbations could influence the variations in both phenomena.展开更多
Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water...Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.展开更多
The montane closed evergreen forests found at altitudes above 1,800 m in the Western Ghats of India possess a distinct vegetation type and are called shola forests. Despite the fact that these forests are located in r...The montane closed evergreen forests found at altitudes above 1,800 m in the Western Ghats of India possess a distinct vegetation type and are called shola forests. Despite the fact that these forests are located in relatively inaccessible areas, they are still under anthropogenic pressure leading to continued habitat degradation and loss of biomass and biodiversity. A case study was conducted in Mananvan shola, the largest shola forest in Kerala of Western Ghats, to recognize the impact of disturbance on vegetation structure, composition and regeneration pattern, to identify the socio-economic reasons for disturbance and to evolve strategies for its management. In the disturbed part of the forest, dominance of light demanding species in tree, shrub and herb communities has been recorded. Here even the dominance of exotic species in tree seedling, shrub and herb communities is prominent. Skewed girth class distribution of tree community with poor representation by the individuals of girth class 30.1 to 90.0 cm, is also an indication of the collection of small wood and poles from the forest. The RISQ (Ramakrishnan Index of Stand Quality) in the disturbed area of the forest is above 2.0 as against near to 1.0 in relatively undisturbed forest standssuggesting that the disturbance is intensive and thus natural recovery process would be slow. Socio- economic analysis in villages located near the shola forest revealed the fact that the people depended heavily on this forest for their livelihood. Thus, the crux and the success of future management and conservation strategy depend on how one can reduce the dependency of people on the shola vegetation. Enrichment planting in disturbed parts of shola, enhancement of firewood by raising energy plantations, as well as development of lemongrass and firewood based agroforestry systems and reduction of grazing pressure by developing silvopastoral systems are the major strategies for the conservation of these shola forests.展开更多
Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,pr...Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.展开更多
Wildfires can result from natural causes like lightning,volcanoes,and earthquakes.In Brazil,though,volcanoes and earthquakes are rare.The surge in fires over the past decade is linked to human activities,mainly defore...Wildfires can result from natural causes like lightning,volcanoes,and earthquakes.In Brazil,though,volcanoes and earthquakes are rare.The surge in fires over the past decade is linked to human activities,mainly deforestation driven by foreign interests searching for strategic minerals in low-productivity areas.This extensive mining affects the environment and climate,jeopardizes lives,impacts local birth rates and young women,and ultimately threatens entire populations seeking a dignified life.展开更多
Miombo woodlands near human settlements are under significant pressures from human activities,with negative consequences on their structure and composition.As studies are limited,we assessed the structure and species ...Miombo woodlands near human settlements are under significant pressures from human activities,with negative consequences on their structure and composition.As studies are limited,we assessed the structure and species composition of a portion of miombo woodland along an increasing disturbance gradient from a national park,through a buffer zone to communal lands in northeast Zimbabwe.Five concentric plots of 2 and 11 m radii were established in each area to record woody species composition,diameter,height,basal area,density and volume as well as evidence of disturbance.Effects of site,growth stage and their interaction on vegetation diversity and structural parameters were tested using a general linear model(GLM).Principal component analysis(PCA) tested the association between species and site and ANOVA the differences in the level of disturbance across strata.Species diversity did not differ between sites except for evenness,which increased with disturbance.Evenness and richness were greater in seedlings and saplings than mature trees across sites,respectively.Sapling and mature tree diameters differed significantly between sites.Volume and density of mature trees declined with increasing disturbance while seedling densities peaked at intermediate disturbance levels(buffer zone).Tree harvesting,was more evident in the buffer zone and in the communal area relative to the national park.In contrast,fire frequency was greater in the national park and in the buffer zone relative to the communal area.The results of this study identify a true miombo woodland dominated by Brachystegia boehmii with a stable population,as illustrated by an inverse-J shape in diameter class distribution on all sites,and that these woodlands are generally resilient to disturbances,maintaining similar species composition and structure at various levels of disturbance.However,continued monitoring of disturbance levels and miombo woodland response is recommended to ensure sustainable utilisation of these resources.展开更多
Changes in forest biomass and soil organic carbon reserves have strong links to atmospheric carbon dioxide concentration.Human activities such as livestock grazing,forest fires,selective logging and firewood extractio...Changes in forest biomass and soil organic carbon reserves have strong links to atmospheric carbon dioxide concentration.Human activities such as livestock grazing,forest fires,selective logging and firewood extraction are the common disturbances that affect the carbon dynamics of the forest ecosystems.Here,we hypothesized that such anthropogenic activities significantly reduce the carbon stocks and accumulation rates in the tropical highland forests of the Sierra Madre de Chiapas in Southern Mexico.We sampled the Pinus oocarpa Scheide dominated forests within the elevation range of 900 to 1100 m above sea level in 2010,2014 and 2017.We measured the stand structural properties and used the reported allometric equations to calculate the tree carbon stocks.Stock change approach was used to calculate carbon accumulation rates.The results showed a gradual increase in carbon storage over the 7-year period from 2010 to 2017,but the rate of increase varied significantly between the study sites.The aboveground carbon stock was 107.25±11.77 Mg ha-1 for the site with lower anthropogenic intensity,compared to 74.29±16.85 Mg ha-1 for the site with higher intensity.The current annual increment for the forest with lower anthropogenic intensity was 7.81±0.65 Mg ha-1 a-1,compared to 3.87±1.03 Mg ha-1 a-1 in the site with high anthropogenic intensity.Although at varying rates,these forests are functioning as important carbon sinks.The results on carbon accumulation rates have important implications in greenhouse gas mitigations and forest change modelling in the context of changing global climate.展开更多
The soil seed bank is an important source of restoration and resilience of disturbed ecosystems. This study evaluates the regeneration potential through the soil seed bank of the shrub savannas of Nguela and Mbe in or...The soil seed bank is an important source of restoration and resilience of disturbed ecosystems. This study evaluates the regeneration potential through the soil seed bank of the shrub savannas of Nguela and Mbe in order to predict the eventual dynamics. Three plots of 0.25 ha subdivided into four sub-plots of 0.015 ha have been installed in each savannah. In total, 48 samples of each savannah, i.e. 96 samples of both savannas, have been taken from the soil layers, 0 - 5 cm, 5 - 10 cm, 10 - 15 cm and 15 - 20 cm. Species diversity and abundance of the soil seed bank have been assessed after germination. The results reveal 167 seedlings belonging to 23 species in the Mbe savannah and 144 seedlings belonging to 14 species in the Nguela savannah. The total densities of the germinated seeds were respectively 463.63 seeds/m<sup>2</sup> and 400 seeds/m<sup>2</sup>. Nevertheless, the 20 cm deep layers have illustrated themselves compared to the superficial layers with densities of 16.29 seeds/m<sup>2</sup> and 21.66 seeds/m<sup>2</sup>, respectively, in the savannas of Mbe and Nguela. Herbaceous species largely dominated, with percentages of 91% and 100%, respectively, in the savannas of Mbe and Nguela. Alone, the Trema orientalis (L.) Blume species has been identified as woody species in the Mbe savannah. The greatest specific richness has been obtained in the first five centimeters of soil, with 21.73% and 28.57% of exclusive species, respectively, in the savannas of Mbe and Nguela. The results reveal that restoration through the soil seed bank would be limited to a single woody species found (T. orientalis). Consequently, the study suggests silvicultural interventions based on planting or enrichment techniques for sustainably managed savannas exposed to anthropogenic disturbances.展开更多
Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low na...Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low native diversity' vs. ‘high native diversity', is supported by the regional distribution patterns of invasive plant species in the Himalayas,Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high.Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend.Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that ‘high native diversity' supports or facilitates invasive plant species. Further, it indicates that nativeand invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors.展开更多
Mount Hilong-hilong is a key biodiversity area, spanning several municipalities in the provinces of the Caraga Region （Agusan del Norte, Agusan del Sur, Surigao del Norte and Surigao del Sur）, northeastern Mindanao ...Mount Hilong-hilong is a key biodiversity area, spanning several municipalities in the provinces of the Caraga Region （Agusan del Norte, Agusan del Sur, Surigao del Norte and Surigao del Sur）, northeastern Mindanao Island, southern Philippines. The Hilong-hilong massif remains one of the most signiifcant forested areas in Mindanao, threatened with habitat modification （forest removal, degradation） and other anthropogenic disturbances related to renewable resource extraction. Amphibians are key indicator species for environmental quality and are useful focal taxa for conservation efforts. Relying on historical museum database information and new survey work on Mount Hilong-hilong, we provide species accounts and describe microhabitat preferences of the anurans （frogs and toads） present in the area. Twenty-seven species representing seven anuran families were studied in detail at elevations between 700 to 1300 meters above sea level; 16 of these species are Mindanao faunal region endemics. Qualitative overlap in microhabitat use was observed, suggesting that, for the species recorded, intact forest may ensure species persistence to some levels of anthropogenic disturbance. A more extensive herpetofaunal survey is needed to fully estimate the herpetofaunal diversity of Mount Hilong-hilong. Because amphibians represent ifne-scale indicators of environmental quality and microendemism, we recommend appropriate ifne-scaled regional strategies geared towards the conservation of amphibians in the Caraga area, northeast Mindanao Island.展开更多
In order to realize the significance of oak forests for ecology and economy of the Himalayan region,the present study attempts to objectively characterize disturbance intensities and their impacts on compositional fea...In order to realize the significance of oak forests for ecology and economy of the Himalayan region,the present study attempts to objectively characterize disturbance intensities and their impacts on compositional features of identified Oak forests, i.e.Banj-oak(Quercus leucotrichophora A.Camus), Tilonj-oak(Q.floribunda Lindley)and Kharsu-oak(Q. semecarpifolia J.E.Smith)in west Himalaya. Amongst studied forests,Q.leucotrichophora and Q. semecarpifolia forests exhibited high sensitivity towards disturbance intensities.In both forests, increasing level of disturbance significantly lowered tree density,dominance and natural recruitment (seedling and sapling density).Q.floribunda forests, however,appeared relatively more resilient to anthropogenic disturbances.Amongst studied oak forests,Q.semecarpifolia forests with overall poor natural regeneration are in a most critically endangered demographic state.However,a slightly improved regeneration(i.e.,seedling density)in moderately disturbed plots is indicative that such plots may be utilized most suitably for in situ revival of these forests.Effect of disturbance intensities on tree population is an important subject for forest ecology and management and the present study highlights a need for adopting different management strategies across disturbance intensities in diverse oak forests of west Himalaya.展开更多
Forest resource conservation has been widely accepted as a key to sustain the local and regional economic development. The forest edges are affected by anthropogenic activities including deforestation, forest fragment...Forest resource conservation has been widely accepted as a key to sustain the local and regional economic development. The forest edges are affected by anthropogenic activities including deforestation, forest fragmentation, selective logging, extraction of non-timber forest products, collection of medicinal plants, recreations, hydroelectric pro- jects and its associated developmental activities, which alter the biodiver- sity. The present study intends to evaluate the edge effect on vegetation structure and species compositions in the tropical forest ecosystems at Periyar Wildlife Sanctuary in the Western Ghats. High species richness （number of species） and Shannon＇s diversity indices were observed in the site IlI （completely undisturbed forest） compared to site I （adjacent to the village/edge of the forest, which is next to the teal（ plantation, severely disturbed forest） and site II （in between the undisturbed forest and mod- erately disturbed forest） while density of tree species showed greater value in site II. Single species such as Tectona grandis （IVI of 80） and Terminaliapaniculata （IVI of 112） were the dominant tree species in site I and site II, respectively, whereas, in site III Terminalia bellirica, Bishofia javanica and Syzgium gardneri shared the dominance. Perturba- tion leads to alien plant invasion particularly Lantana camara, Eupato- rium odoratum and Ageratum conizoides. Site II is at forest transition level because the site is dominated by both natural species as well as plantation species such as Tectona grandis. This site seems to be a buffer zone on natural forest and plantations. Further studies are required to analyse the real patterns of regeneration and dynamic change due to human impact by long term monitoring with the establishment of perma- nent plots.展开更多
The Anthropocene proposal suggested that the Earth may have entered a new geological epoch,in which human activity and climate change are influencing the environment at global scale.Arrival of the Anthropocene is brin...The Anthropocene proposal suggested that the Earth may have entered a new geological epoch,in which human activity and climate change are influencing the environment at global scale.Arrival of the Anthropocene is bringing an unprecedented challenge to the biodiversity that is essential to humans,and enhancing many benefits of nature to human being.However,biodiversity loss is aggravating in the rhythm of inevitable change in the Anthropocene,and the adaptation of biodiversity to the anthropogenic disturbance seems unable to keep pace with the human activity and climate change.Therefore,re-examination of the assumptions and practices upon the current conservation endeavor are needed.We suggested that biodiversity conservation should be paid more attention to the response from biodiversity to the human activity and climate change in the Anthropocene.Thus,the concept of biodiversity arks in the Anthropocene is proposed,that is,biodiversity arks in the Anthropocene are the areas where vulnerable biodiversity is sheltered to alleviate human activity and buffered from climate change under the anthropogenic disturbance.The concept should be implemented for biodiversity conservation to fill gaps between our knowledge and build on successful conservation and sustainability in the Anthropocene.It will be certainly important to conservation policy instruction and management under climate change,especially the implementation of climate buffering zones preserving biodiversity in the face of warming climate.展开更多
Assessment of tree species diversity, structure and regeneration status of four sacred groves of Kushalnagar,southern Karnataka was carried out. The random quadrat method was employed in each grove for enumeration of ...Assessment of tree species diversity, structure and regeneration status of four sacred groves of Kushalnagar,southern Karnataka was carried out. The random quadrat method was employed in each grove for enumeration of tree diversity and regeneration status. A total of 98 tree species belonging to 38 families were found from the sampled areas.These groves possess higher diversity and basal area. Some67 % of species have shown regeneration, while 17 % of species had no regeneration. Another 15 % of species were reappearing or immigrating. It is observed that increased disturbance was directly proportional to number of reappearing or immigrating species and inversely proportional to the diversity in all the sacred groves. Significant impact on diversity, species richness and regeneration status of the flora due to manifold anthropogenic activities have been recorded.展开更多
文摘The present study assesses anthropogenic disturbances and their impacts on the vegetation in Western Himalaya,India on the basis of various disturbance parameters such as density,Total Basal Cover(TBC) of cut stumps,lopping percentage and grazing intensities.On the basis of canopy cover and frequency of disturbances(%),the studied forests were divided into highly disturbed(HD),moderately disturbed(MD) and least disturbed(LD) categories.The HD forests had the lowest canopy cover,lowest density and lowest TBC and the LD had the highest canopy cover,highest density and highest TBC.The MD forests occupied the intermediate position with respect to these parameters.Species richness was least in HD forests,highest in one of the MD forests while LD forest occupied an intermediate position.The percentage of regenerating species was lowest(54%) in HD and highest(72%) in MD.The density of seedlings and saplings was higher in one of the MD forests as compared to HD and LD.We concluded that the moderate disturbances do not affect the vegetation adversely;however the increased degree of disturbance causes loss in plant diversity;affects regeneration and changes community characteristics.Construction of hydroelectric projects at various places in the study area was found to be one of the most important sources of anthropogenic disturbances in addition to the routine anthropogenic disturbances like grazing,fuelwood collection and fodder extraction.If all proposed dams in the Indian Himalaya are constructed combined with weak national environmental impact assessment and implementation,it will result in a significant loss of species.Therefore,various agents of disturbances should be evaluated in cumulative manner and any developmental activities such as hydropower projects,which trigger various natural and anthropogenic disturbances,should be combined with proper cumulative environmental impact assessment and effective implementation to minimise the anticipated loss of vegetation.
基金supported by Kenya Forestry Research Institute(KEFRI/FBEM 2014_2015/2.3)International Foundation for Science(IFS D5452-1)
文摘Despite the ecological and economic importance of Acacia senegal, little is known about the effects of anthropogenic disturbances on its natural regeneration patterns and population structure. We investigated the effects of these factors within the Lake Baringo woodland ecosystem. Data was collected from 60 plots of 20 m × 20 m systematically distributed in four A. senegal-dominated populations within the Lake Baringo woodland. Sample populations spanned a degradation gradient measured by a population disturbance index (PDI). Trees were measured for diameter at breast height (DBH) and categorized by growth stages: seedling, sapling and adult tree. Higher seedling and sapling densities were recorded in lightly than heavily disturbed populations, but only sapling density was significantly different between the two disturbance levels (P = 0.02). Lightly disturbed populations revealed a reversed J-shape size-class distribution (SCD) indicative of stable structure unlike the heavily disturbed populations. The quotient and permutation indices indicated unstable populations with episodic recruitment and mortality. Our study reveals that natural regeneration and population structure of A. senegal were affected majorly by selective harvesting and heavy browsing. Suitable management strategies to control livestock grazing and illegal tree harvesting within the woodland is required to promote conservation of the species genetic resources
基金the projects of National Natural Science Foundation of China(21077119)National Basic Research Program of China(2009CB421103)+2 种基金Special Fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(12L03ESPC)Beijing Nova Program(2011095)K.C.Wong Education Foundation,Hong Kong
文摘The diversity of Planctomycetes and related bacteria in 3 types of freshwater wetlands with different anthropogenic disturbances were investigated by cloning and sequencing PCR-amplified partial 16S rRNA genes. Three clone libraries were constructed using 16S rRNA-targeted forward PCR primer specific for Planctomycetales and general bacterial reverse primer. Phylogenetic analysis of the 16S rRNA gene sequences defined 95 operational taxonomic units (OTUs) with 163 sequences. The clone libraries covered a wide microbial diversity of Proteobacteria and the Planctomycetes-Verrucomicrobia-Chlamydiales (PVC) superphylum. The majority of the OTUs were related to the phylum of Planctomycetes (33 OTUs), Proteobacteria (22 OTUs) and Verrucomicrobia (22 OTUs). Four known genera from the Planctomycetes phylum were all detected. The genus Pirellula (18 OTUs) dominated the Planctomycetes community, but different patterns of distribution were observed in the wetlands. The littoral wetlands of Baiyangdian Lake with the least anthropogenic disturbances covered more species and showed the highest biodiversity. However, the Jiaxing paddy fields with the highest anthropogenic disturbances showed a higher biodiversity than that in the riparian wetlands of the North Canal. Bacteria distantly related to anammox bacteria were also detected with a small proportion (4 OTUs). It showed that wetlands hold a great biodiversity of phyla Planctomycetes and related bacteria; furthermore, there is ample opportunity to discover novel phylotypes of Planctomycetes in the wetland ecosystems.
文摘Almost three-fourths of forests are experiencing anthropogenic disturbances globally, and more than two-thirds of the forests in Nepal receive different types of disturbances. In community forests(CFs), local communities are dependent on the ecosystem services provided by the forests for various aspects of their livelihoods, which disturb the forests’ natural conditions and ecosystem functioning in a variety of ways. This study tested the major disturbance factors that had influential roles on plant species diversity, recruitment(seedlings and saplings), biomass, soil organic carbon(SOC) and total carbon density in two community-managed forests in the Mid-hills of Nepal. The stump number, cut-off seedlings and saplings, lopping, dropping, and grazing/trampling were used as measures of the major anthropogenic disturbances. The necessary data were collected from 89 randomly selected sample plots, each with an area of 250 m2. The responses to anthropogenic disturbances were analyzed using Generalized Linear Models(GLM). The results showed that forest lopping was the most significant anthropogenic disturbance for biomass and total carbon density balance. A higher degree of lopping in the forests resulted in a lowering of the forests’ carbon stock in the study area. SOC showed no significant response to any of the tested anthropogenic disturbances. Woody species richness and number of saplings increased with an increasing number of stumps, which signifies that intermediate disturbance was beneficial. However, a higher intensity of lopping reduced the sapling density. Grazing/trampling was the most significant disturbance for inhibiting seedling growth. Areas in the forests with a higher intensity of trampling showed lower numbers of seedlings and saplings. These results will be a guide for managing anthropogenic disturbances in multiple-use forests in Nepal, as well as those in similar socio-economic environments worldwide.
基金This work was supported by the National Natural Science Foundation of China(31560181)The Biodiversity Survey and Assessment Project of the Ministry of Ecology and Environment,China(2019HJ2096001006).
文摘Aims The aims of this study were to assess how functional diversity(FD)and functional redundancy respond to subalpine meadow ecosystem degradation under anthropogenic disturbance and how species contribute to functional redundancy along the disturbance gradient.Methods The study was carried out in the subalpine meadow in Mount Jade Dragon,which is located at the southeastern edge of the Tibetan Plateau.Four disturbance intensities[no disturbance(ND),weak disturbance(WD),moderate disturbance(MD)and severe disturbance(SD)]were identified.Species richness,soil properties and five key plant functional traits were assessed along the disturbance gradient.Simpson’s diversity index,FD based on the Rao algorithm,functional redundancy,community-weighted mean of each functional trait and species-level functional redundancy were determined.Important Findings Unimodal change pattern of FD and functional redundancy along the disturbance gradient were found in the present study,with their maximum in MD and WD,respectively.Species diversity showed a decreasing trend with increasing disturbance intensity.As disturbance intensified,species with traits related to conservative growth strategies,such as low specific leaf area(SLA)and high leaf dry matter content(LDMC),decreased,whereas species with resource acquisitive strategies,such as small plant,high SLA and low LDMC,increased in the community.At the species level,species showed species-specific roles in functional redundancy.Notably,some species were important in the community in terms of their unique function.For instance,Ligularia dictyoneura in ND and Potentilla delavayi in MD and SD.
文摘The survival chance of epiphytie orchids today not only depends on the natural site conditions required by the orchids but also on anthropogenic changes in site conditions. This study answers two questions： （1） What is the ecological niche of the different epiphytic orchid species？ （2） What are the ecological factors that threaten epiphytic orchid＇s population under anthropogenic disturbances？ Our study area was the Kathmandu valley, Nepal, with its subtropical forest. We established 156 systematically selected sampling points in the Kathmandu area covering different types of ecosystems under human impacts such as densely populated area, agricultural land, mixed agricultural and settled area, old tree patches, and a natural forest in a national park. The ecological niche of the orchid species was analyzed with a principal component analysis （PCA）. The correlations between the different site factors were statistically significant. Spearman＇s rank correlation matrices showed that the variables land-use intensities with altitude, and height with diameter in breast height （dbh） of host had the highest significant positive correlation coefficient （0.67 and 0.64 respectively）. On the other hand, host bark pH and altitude as well as land use had a significantly strong negative correlation coefficient （-0.80 and -0.61, respectively）. Different epiphytic orchid species interact differently with the given set of environmental factors： for occurrence of Vanda cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and high light availability are important. First two axis of the PCA explained more than 50% of the total variance. Most orchid species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid population in the Kathmandu Valley are loss of adequate host trees （species and size） and increasing air pollution, resulting in increasing host bark pH.
文摘This paper investigated the information about Ice sheet melt and Ozone hole variations during three solar cycles. After performing the inquiry on the data, the final results pointed out that both phenomena varying accord with Earth’s seasonality. The sea melt extension depends on the season and if the ocean waters are warmer around the polar caps. We checked the suggestion that anthropogenic perturbations could influence the variations in both phenomena.
文摘Malaysia's rapid economic and demographic development have placed negative pressure on its water supplies and the quality of the Juru River, which is close to the nation's capital and its major source of water. Healthy aquatic ecosystems are supported by physicochemical properties and biological diversity. This study evaluated the anthropogenic impacts on aquatic biodiversity, especially plankton, fish, and macrobenthos, as well as the water quality of the Juru River in the Penang area. Aquatic biodiversity and river water parameters were collected from ten sampling stations along the Juru River. Seven variables were used to assess the physicochemical environment: pH, temperature, total suspended solids (TSS), salinity, dissolved oxygen (DO), biochemical oxygen demand (BOD), and chemical oxygen demand. At each sampling station, the total number of plankton, fish, and macrobenthic taxa were counted and analyzed. The relationships between the physicochemical parameters and aquatic biodiversity were investigated with biotypological analysis, principal component analysis, hierarchical cluster analysis, and linear regression analysis. These analyses showed that the richness and diversity indices were generally influenced by salinity, temperature, TSS, BOD, and pH. The data obtained in this study supported the bioindicator concept. The findings, as they related to scientifically informed conservation, could serve as a model for Juru River management, as well as for river management throughout Malaysia and other tropical Asian countries.
文摘The montane closed evergreen forests found at altitudes above 1,800 m in the Western Ghats of India possess a distinct vegetation type and are called shola forests. Despite the fact that these forests are located in relatively inaccessible areas, they are still under anthropogenic pressure leading to continued habitat degradation and loss of biomass and biodiversity. A case study was conducted in Mananvan shola, the largest shola forest in Kerala of Western Ghats, to recognize the impact of disturbance on vegetation structure, composition and regeneration pattern, to identify the socio-economic reasons for disturbance and to evolve strategies for its management. In the disturbed part of the forest, dominance of light demanding species in tree, shrub and herb communities has been recorded. Here even the dominance of exotic species in tree seedling, shrub and herb communities is prominent. Skewed girth class distribution of tree community with poor representation by the individuals of girth class 30.1 to 90.0 cm, is also an indication of the collection of small wood and poles from the forest. The RISQ (Ramakrishnan Index of Stand Quality) in the disturbed area of the forest is above 2.0 as against near to 1.0 in relatively undisturbed forest standssuggesting that the disturbance is intensive and thus natural recovery process would be slow. Socio- economic analysis in villages located near the shola forest revealed the fact that the people depended heavily on this forest for their livelihood. Thus, the crux and the success of future management and conservation strategy depend on how one can reduce the dependency of people on the shola vegetation. Enrichment planting in disturbed parts of shola, enhancement of firewood by raising energy plantations, as well as development of lemongrass and firewood based agroforestry systems and reduction of grazing pressure by developing silvopastoral systems are the major strategies for the conservation of these shola forests.
基金supported by the National Natural Science Foundation of China(32071529)the Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station(Z202204)+1 种基金Shanghai Key Lab for Urban Ecological Processes and EcoRestoration(SHUES2020B06,SHUES2021C04)the Fundamental Research Funds for the Central Universities.
文摘Human disturbances are considered to break reproduction barriers among species.Significant increases in hybridization events have been reported among a large number of taxonomic groups in anthropogenic environments,providing novel insights into species evolution mechanisms and conservation management in the Anthropocene.The Eastern Golden Frog(Pelophylax plancyi)and BlackSpotted Frog(P.nigromaculatus)are two sympatric anuran species with a long history of mitochondrial genome introgression in highly urbanized continental East Asia.However,there is only limited understanding of the pattern of their contemporary hybridization and factors influencing their interspecific relationship under anthropogenic disturbances.Here,interspecific hybridization between P.plancyi and P.nigromaculatus at the population level was investigated in Shanghai.All except two haplotypes obtained from both species in Shanghai were mixed together,and located in the introgression clade,implying multiple ancient mitochondrial introgression events occurred in the populations of our study area.Asymmetric genetic introgression was detected by microsatellite markers,with 0.7%of P.plancyi and 14.6%of P.nigromaculatus identified as contemporary admixed individuals.Consistent with the trend of population density,higher genetic diversity of neutral microsatellite loci was found in the more abundant P.plancyi;however,variation in mitochondrial(Cyt-b)and nuclear(POMC)genes was higher in relatively rare P.nigromaculatus.The population density of P.plancyi and number of water patches within local habitats were significantly positively correlated with both occurrences and proportions of admixed individuals in the populations of P.plancyi and P.nigromaculatus.Considering the prevalent transformation of habitats in urbanized areas,these results imply that a high population density in isolated artificially altered habitats is likely to increase interspecific hybridization.Thus,population monitoring and improvement of landscape connectivity between habitats would be needed to control the intensity of interspecific hybridization between P.plancyi and P.nigromaculatus in anthropogenic-disturbed environments.
文摘Wildfires can result from natural causes like lightning,volcanoes,and earthquakes.In Brazil,though,volcanoes and earthquakes are rare.The surge in fires over the past decade is linked to human activities,mainly deforestation driven by foreign interests searching for strategic minerals in low-productivity areas.This extensive mining affects the environment and climate,jeopardizes lives,impacts local birth rates and young women,and ultimately threatens entire populations seeking a dignified life.
文摘Miombo woodlands near human settlements are under significant pressures from human activities,with negative consequences on their structure and composition.As studies are limited,we assessed the structure and species composition of a portion of miombo woodland along an increasing disturbance gradient from a national park,through a buffer zone to communal lands in northeast Zimbabwe.Five concentric plots of 2 and 11 m radii were established in each area to record woody species composition,diameter,height,basal area,density and volume as well as evidence of disturbance.Effects of site,growth stage and their interaction on vegetation diversity and structural parameters were tested using a general linear model(GLM).Principal component analysis(PCA) tested the association between species and site and ANOVA the differences in the level of disturbance across strata.Species diversity did not differ between sites except for evenness,which increased with disturbance.Evenness and richness were greater in seedlings and saplings than mature trees across sites,respectively.Sapling and mature tree diameters differed significantly between sites.Volume and density of mature trees declined with increasing disturbance while seedling densities peaked at intermediate disturbance levels(buffer zone).Tree harvesting,was more evident in the buffer zone and in the communal area relative to the national park.In contrast,fire frequency was greater in the national park and in the buffer zone relative to the communal area.The results of this study identify a true miombo woodland dominated by Brachystegia boehmii with a stable population,as illustrated by an inverse-J shape in diameter class distribution on all sites,and that these woodlands are generally resilient to disturbances,maintaining similar species composition and structure at various levels of disturbance.However,continued monitoring of disturbance levels and miombo woodland response is recommended to ensure sustainable utilisation of these resources.
基金We thank BIOMASA A.C.and Mexico REDD+program for supporting part of the fieldwork.We are thankful to Carrie Mitchell for English revision of the manuscript.We acknowledge the constructive comments from the reviewers on the earlier version of the article.
文摘Changes in forest biomass and soil organic carbon reserves have strong links to atmospheric carbon dioxide concentration.Human activities such as livestock grazing,forest fires,selective logging and firewood extraction are the common disturbances that affect the carbon dynamics of the forest ecosystems.Here,we hypothesized that such anthropogenic activities significantly reduce the carbon stocks and accumulation rates in the tropical highland forests of the Sierra Madre de Chiapas in Southern Mexico.We sampled the Pinus oocarpa Scheide dominated forests within the elevation range of 900 to 1100 m above sea level in 2010,2014 and 2017.We measured the stand structural properties and used the reported allometric equations to calculate the tree carbon stocks.Stock change approach was used to calculate carbon accumulation rates.The results showed a gradual increase in carbon storage over the 7-year period from 2010 to 2017,but the rate of increase varied significantly between the study sites.The aboveground carbon stock was 107.25±11.77 Mg ha-1 for the site with lower anthropogenic intensity,compared to 74.29±16.85 Mg ha-1 for the site with higher intensity.The current annual increment for the forest with lower anthropogenic intensity was 7.81±0.65 Mg ha-1 a-1,compared to 3.87±1.03 Mg ha-1 a-1 in the site with high anthropogenic intensity.Although at varying rates,these forests are functioning as important carbon sinks.The results on carbon accumulation rates have important implications in greenhouse gas mitigations and forest change modelling in the context of changing global climate.
文摘The soil seed bank is an important source of restoration and resilience of disturbed ecosystems. This study evaluates the regeneration potential through the soil seed bank of the shrub savannas of Nguela and Mbe in order to predict the eventual dynamics. Three plots of 0.25 ha subdivided into four sub-plots of 0.015 ha have been installed in each savannah. In total, 48 samples of each savannah, i.e. 96 samples of both savannas, have been taken from the soil layers, 0 - 5 cm, 5 - 10 cm, 10 - 15 cm and 15 - 20 cm. Species diversity and abundance of the soil seed bank have been assessed after germination. The results reveal 167 seedlings belonging to 23 species in the Mbe savannah and 144 seedlings belonging to 14 species in the Nguela savannah. The total densities of the germinated seeds were respectively 463.63 seeds/m<sup>2</sup> and 400 seeds/m<sup>2</sup>. Nevertheless, the 20 cm deep layers have illustrated themselves compared to the superficial layers with densities of 16.29 seeds/m<sup>2</sup> and 21.66 seeds/m<sup>2</sup>, respectively, in the savannas of Mbe and Nguela. Herbaceous species largely dominated, with percentages of 91% and 100%, respectively, in the savannas of Mbe and Nguela. Alone, the Trema orientalis (L.) Blume species has been identified as woody species in the Mbe savannah. The greatest specific richness has been obtained in the first five centimeters of soil, with 21.73% and 28.57% of exclusive species, respectively, in the savannas of Mbe and Nguela. The results reveal that restoration through the soil seed bank would be limited to a single woody species found (T. orientalis). Consequently, the study suggests silvicultural interventions based on planting or enrichment techniques for sustainably managed savannas exposed to anthropogenic disturbances.
基金part of the research project ‘Legal frameworks for Conservation of Biodiversity and Ecosystem Services in the Himalayas (HIMALINES)’ funded by the Norwegian Research Council (190153/V10) Olaf Grolles Legat
文摘Invasive plant species are exerting a serious threat to biological diversity in many regions of the world. To understand plant invasions this study aims to test which of the two plant invasiveness hypotheses; ‘low native diversity' vs. ‘high native diversity', is supported by the regional distribution patterns of invasive plant species in the Himalayas,Nepal. This study is based on data retrieved from published literatures and herbarium specimens. The relationship between invasive plant species distribution patterns and that of native plant species is elucidated by scatter plots, as well as by generalized linear models. The native plant species and invasive plant species have similar distribution patterns and the maximum number of invasive plant species is found in the same altitudinal range where the highest richness for native tree species is found. There is a clear trend of higher invasive plant richness in regions where native tree species richness is relatively high.Consequently, the native plant richness is highest in the central phytogeographic region, followed by the eastern and the western regions, respectively. The invasive plant species also follows a similar trend.Additionally, the invasive plant species richness was positively correlated with anthropogenic factors such as human population density and the number of visiting tourists. This study supports the hypothesis that ‘high native diversity' supports or facilitates invasive plant species. Further, it indicates that nativeand invasive plant species may require similar natural conditions, but that the invasive plant species seem more dependent and influenced by anthropogenic disturbance factors.
文摘Mount Hilong-hilong is a key biodiversity area, spanning several municipalities in the provinces of the Caraga Region （Agusan del Norte, Agusan del Sur, Surigao del Norte and Surigao del Sur）, northeastern Mindanao Island, southern Philippines. The Hilong-hilong massif remains one of the most signiifcant forested areas in Mindanao, threatened with habitat modification （forest removal, degradation） and other anthropogenic disturbances related to renewable resource extraction. Amphibians are key indicator species for environmental quality and are useful focal taxa for conservation efforts. Relying on historical museum database information and new survey work on Mount Hilong-hilong, we provide species accounts and describe microhabitat preferences of the anurans （frogs and toads） present in the area. Twenty-seven species representing seven anuran families were studied in detail at elevations between 700 to 1300 meters above sea level; 16 of these species are Mindanao faunal region endemics. Qualitative overlap in microhabitat use was observed, suggesting that, for the species recorded, intact forest may ensure species persistence to some levels of anthropogenic disturbance. A more extensive herpetofaunal survey is needed to fully estimate the herpetofaunal diversity of Mount Hilong-hilong. Because amphibians represent ifne-scale indicators of environmental quality and microendemism, we recommend appropriate ifne-scaled regional strategies geared towards the conservation of amphibians in the Caraga area, northeast Mindanao Island.
基金support from Department of Science & Technology,New Delhi(No:SP/SO/A60/99)isgratefully acknowledged
文摘In order to realize the significance of oak forests for ecology and economy of the Himalayan region,the present study attempts to objectively characterize disturbance intensities and their impacts on compositional features of identified Oak forests, i.e.Banj-oak(Quercus leucotrichophora A.Camus), Tilonj-oak(Q.floribunda Lindley)and Kharsu-oak(Q. semecarpifolia J.E.Smith)in west Himalaya. Amongst studied forests,Q.leucotrichophora and Q. semecarpifolia forests exhibited high sensitivity towards disturbance intensities.In both forests, increasing level of disturbance significantly lowered tree density,dominance and natural recruitment (seedling and sapling density).Q.floribunda forests, however,appeared relatively more resilient to anthropogenic disturbances.Amongst studied oak forests,Q.semecarpifolia forests with overall poor natural regeneration are in a most critically endangered demographic state.However,a slightly improved regeneration(i.e.,seedling density)in moderately disturbed plots is indicative that such plots may be utilized most suitably for in situ revival of these forests.Effect of disturbance intensities on tree population is an important subject for forest ecology and management and the present study highlights a need for adopting different management strategies across disturbance intensities in diverse oak forests of west Himalaya.
文摘Forest resource conservation has been widely accepted as a key to sustain the local and regional economic development. The forest edges are affected by anthropogenic activities including deforestation, forest fragmentation, selective logging, extraction of non-timber forest products, collection of medicinal plants, recreations, hydroelectric pro- jects and its associated developmental activities, which alter the biodiver- sity. The present study intends to evaluate the edge effect on vegetation structure and species compositions in the tropical forest ecosystems at Periyar Wildlife Sanctuary in the Western Ghats. High species richness （number of species） and Shannon＇s diversity indices were observed in the site IlI （completely undisturbed forest） compared to site I （adjacent to the village/edge of the forest, which is next to the teal（ plantation, severely disturbed forest） and site II （in between the undisturbed forest and mod- erately disturbed forest） while density of tree species showed greater value in site II. Single species such as Tectona grandis （IVI of 80） and Terminaliapaniculata （IVI of 112） were the dominant tree species in site I and site II, respectively, whereas, in site III Terminalia bellirica, Bishofia javanica and Syzgium gardneri shared the dominance. Perturba- tion leads to alien plant invasion particularly Lantana camara, Eupato- rium odoratum and Ageratum conizoides. Site II is at forest transition level because the site is dominated by both natural species as well as plantation species such as Tectona grandis. This site seems to be a buffer zone on natural forest and plantations. Further studies are required to analyse the real patterns of regeneration and dynamic change due to human impact by long term monitoring with the establishment of perma- nent plots.
基金This work was financially supported by the Southeast Asia Biodiversity Research Institute,Chinese Academy of Sciences(Y4ZK111B01)the Youth Innovation Promotion Association,Chinese Academy of Sciences(2018432).
文摘The Anthropocene proposal suggested that the Earth may have entered a new geological epoch,in which human activity and climate change are influencing the environment at global scale.Arrival of the Anthropocene is bringing an unprecedented challenge to the biodiversity that is essential to humans,and enhancing many benefits of nature to human being.However,biodiversity loss is aggravating in the rhythm of inevitable change in the Anthropocene,and the adaptation of biodiversity to the anthropogenic disturbance seems unable to keep pace with the human activity and climate change.Therefore,re-examination of the assumptions and practices upon the current conservation endeavor are needed.We suggested that biodiversity conservation should be paid more attention to the response from biodiversity to the human activity and climate change in the Anthropocene.Thus,the concept of biodiversity arks in the Anthropocene is proposed,that is,biodiversity arks in the Anthropocene are the areas where vulnerable biodiversity is sheltered to alleviate human activity and buffered from climate change under the anthropogenic disturbance.The concept should be implemented for biodiversity conservation to fill gaps between our knowledge and build on successful conservation and sustainability in the Anthropocene.It will be certainly important to conservation policy instruction and management under climate change,especially the implementation of climate buffering zones preserving biodiversity in the face of warming climate.
文摘Assessment of tree species diversity, structure and regeneration status of four sacred groves of Kushalnagar,southern Karnataka was carried out. The random quadrat method was employed in each grove for enumeration of tree diversity and regeneration status. A total of 98 tree species belonging to 38 families were found from the sampled areas.These groves possess higher diversity and basal area. Some67 % of species have shown regeneration, while 17 % of species had no regeneration. Another 15 % of species were reappearing or immigrating. It is observed that increased disturbance was directly proportional to number of reappearing or immigrating species and inversely proportional to the diversity in all the sacred groves. Significant impact on diversity, species richness and regeneration status of the flora due to manifold anthropogenic activities have been recorded.
