The soil constituents and relations between the variation of soil resources and plant communities in three adjacent sites representing the overgrazing, reclamation and comparatively undisturbed communities respectivel...The soil constituents and relations between the variation of soil resources and plant communities in three adjacent sites representing the overgrazing, reclamation and comparatively undisturbed communities respectively were quantified and examined in study area in Huailai Basin, Hebei Province, China. There have been significantly greater constituent of C, N, P in the soils of shrubland site. Corg, Ntotal, Navail and Pavail were between 1.18 and 3.90 times more concentrated in the soils of shrubland site in comparison with the other two sites. Although the Ptotal concentration was lower in shrubland soils than in overgrazed rangeland soils, the Pavail concentration, however, was significantly greater in the soils of shrubland site, and increased by 59.1% and even 289.6% in the soils of shrubland site comparing to those in the soils of range-land and millet field sites. Among the three sites, CV exceeding 40% were found for SO4, Cl, and F ion. The CV of organic carbon also exceeded 40% but only in the soils of millet field site. The highest CV were found for F, SO4 ion in the soils of shrubland and overgrazed rangeland sites, while for Cl and SO4 ion in those of millet field site. The results also showed that the introductions of shrubs are of vital importance for the accumulation of soil nutrients and maintenance of soil fertilities, and also for the restoration and reconstruction of desertified ecosystems.展开更多
ALASHAN AND ORDOS,Inner Mongolia-Dust,five centimeters thick, and rat holes cover the landscape of the Shilekai village,about 300 kilometers from the city of Ordos, Inner Mongolia.
Background Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plate...Background Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plateau. This research tested the hypothesis that overgrazing might promote Echinococcus multilocularis transmission through increasing populations of small mammal, intermediate hosts in Tibetan pastoral communities. Methods Grazing practices, small mammal indices and dog Echinococcus multilocularis infection data were collected to analyze the relation between overgrazing and Echinococcus multilocularis transmission using nonparametric tests and multiple stepwise logistic regression. Results In the investigated area, raising livestock was a key industry. The communal pastures existed and the available forage was deficient for grazing. Open (common) pastures were overgrazed and had higher burrow density of small mammals compared with neighboring fenced (private) pastures; this high overgrazing pressure on the open pastures measured by neighboring fenced area led to higher burrow density of small mammals in open pastures. The median burrow density of small mammals in open pastures was independently associated with nearby canine Echinococcus multilocularis infection (P=-0.003, OR=1.048). Conclusion Overgrazing may promote the transmission of Echinococcus multilocularis through increasing the population density of small mammals.展开更多
The Three-River Headwaters region in China is an ecological barrier providing en- vironmental protection and regional sustainable development for the mid-stream and down- stream areas, which also plays an important ro...The Three-River Headwaters region in China is an ecological barrier providing en- vironmental protection and regional sustainable development for the mid-stream and down- stream areas, which also plays an important role in animal husbandry in China. This study estimated the grassland yield in the Three-River Headwaters region based on MODIS NPP data, and calculated the proper livestock-carrying capacity of the grassland. We analyzed the overgrazing number and its spatial distribution characteristics through data comparison be- tween actual and proper livestock-carrying capacity. The results showed the following: (1) total grassland yield (hay) in the Three-River Headwaters region was 10.96 million tons in 2010 with an average grassland yield of 465.70 kg/hm2 (the spatial distribution presents a decreasing trend from the east and southeast to the west and northwest in turn); (2) the proper livestock-carrying capacity in the Three-River Headwaters region is 12.19 million sheep units (hereafter described as "SU"), and the average stocking capacity is 51.27 SU [the proper carrying capacity is above 100 SU/km2 in the eastern counties, 60 SU/km2 in the cen- tral counties (except Madoi County), and 30 SU/km2 in the western counties]; and (3) total overgrazing number was 6.52 million SU in the Three-River Headwaters region in 2010, with an average overgrazing ratio of 67.88% and an average overgrazing number of 27.43 SU/km2 A higher overgrazing ratio occurred in Tongde, Xinghai, Yushu, Henan and Z^kog. There was no overgrazing in Zhiduo, Tanggula Township and Darlag, Qumerleb and Madoi. The re- mainder of the counties had varying degrees of overgrazing.展开更多
Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau (QTP) in China. However, it is lacking of studies on the effects of warming and...Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau (QTP) in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments: control (CK), warming (W), clipping (C) and warming+clipping combination (WC). The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial responses of plant and soil properties to experimental warming and clipping were slow and weak, the drought induced by the down- ward shift of soil moisture in the upper soil layers may induce plant belowground biomass to transfer to the deeper soil layers. This movement would modify the distributions of soil activated carbon, organic carbon and total nitrogen However, long-term data collection is needed to further explain this interesting phenomenon.展开更多
St udying the changes in nutrient use strategies induced by grazing can provide insight into the process of grassland degradation and is important for improving grassland quality and enhancing ecosystem function. Domi...St udying the changes in nutrient use strategies induced by grazing can provide insight into the process of grassland degradation and is important for improving grassland quality and enhancing ecosystem function. Dominant species in meadow steppe can optimize their use of limiting resources; however, the regulation of nutrient use strategies across grazing gradients is not fully understood. Therefore, in this study, we report an in situ study in which the impact of grazing rates on nutrient use strategies of Leymus chinensis, the dominant plant species in eastern Eurasian temperate steppes, was investigated. We conducted a large randomized controlled experiment(conducted continuously for five years in grassland plots in a natural pasture in Ha ilar, eastern Mongolia Plateau, China) to assess the effects of grazing rate treatments(0.00, 0.23, 0.34, 0.46, 0.69, and 0.92 adult cattle unit(AU) ha-1) on L. chinensis along a grazing gradient and employed a random sampling approach to compare the accumulation, allocation, and stoichiometry of C, N, and P in leaves and stems. Ou r findings demonstrated the follows:(i) The height of L. chinensis decreased with an increase in the grazing gradient, and the concentrations of C, N, and P significantly increased;(ii) the accumulation of C, N, and P per individual was negatively correlated with the concentration of aboveground tissues, suggesting that there was a tradeoff in L. chinensis between nutrient accumulation and concentration at the individual scale;(iii) the leaf-to-stem ratio of C, N, and P accumulation increased with grazing intensity, indicating a tradeoff in nutrient allocation and plant size at the individual plant level; and(iv) grazing rates were negatively correlated with the ratios of C:N and C:P in the stem; however, these ratios in leaves significantly increased with grazing intensity. Our findings suggest that L. chinensis in meadow steppe adapts to grazing disturbance through tradeoffs between plant size and nutrient use strategies. Moreover, our results imply that grazing produces a compensatory effect on nutrient use efficiency between the stems and leaves of L. chinensis.展开更多
Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelih...Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO<sub>2</sub> as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure arrangements. However, the building of enhanced capacities of pasture management and effective local rangeland governance structures can increase the likelihood, which will be sustainable and equitable. Finally, this paper presented several promising technical options, aiming at reversing the trend of rangeland degradation in Central Asia.展开更多
Horqin Sandy Land is a fragile, seriously desertified region located in Inner Mongolia of China. Over- grazing is one of the primary drivers of desertification in this region. We investigated whether the establishment...Horqin Sandy Land is a fragile, seriously desertified region located in Inner Mongolia of China. Over- grazing is one of the primary drivers of desertification in this region. We investigated whether the establishment of grazing exclosures in areas with active sand dunes enhances soil carbon (C) sequestration and benefits soil re- covery. The results showed that soil organic C storage was 1.4, 1.9, and 3.5 times, and light fraction C storage was 2.3, 3.2, and 4.4 times in the 100-cm topsoil after 7, 12, and 25 years of grazing exclusion, respectively, compared to the case in active sand dunes. The light fraction of soil played an important role in soil C sequestration, although it might not change rapidly to provide an early indication of how soil C is increasing in response to grazing exclusion. The results indicated that soils could potentially sequester up to 13.8 Mt C in 25 years if active sand dunes in the study area were to be protected by exclosures. This corresponds to 12.8% of the estimated carbon loss (107.53 Mt) that has been associated with desertification over the past century in the Horqin Sandy Land. Our results suggested that exclosures have the capacity to increase soil C sequestration; however, decades will be required for soil C to recover to historical grassland levels observed prior to desertification.展开更多
We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo (Kereyu and lttu) Nations in and around the semi=arid Awash National Park (ANP), Ethiopia. The study aimed at investigati...We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo (Kereyu and lttu) Nations in and around the semi=arid Awash National Park (ANP), Ethiopia. The study aimed at investigating and documenting indigenous knowledge (IK) on forage/fodder plant species and threats to their survival. Ninety-six in= formants between 20 and 80 years old were selected using prior informa- tion. Data were collected using semi-structured interview, guided field wail discussion and field observation. Preference ranking, Jaccard's coefficient of similarity and priority ranking were used for data analysis. One hundred twenty-six forage/fodder species of 90 genera and 43 fami- lies were collected in the study area. More than 88% of the species were reported with their vernacular names, where 68% were reported by the Afar Nation and 70% by the Oromo Nation. Family Poaceae was repre- sented by 25 species (20%), followed by Fabaceae 18 (14%). Preference ranking for the most preferred forage grasses as perceived by key informants revealed that Chrysopogon plumulosus was the most important forage/fodder species. Overgrazing was the major threat in the study area, scoring 22%.展开更多
In the study area located in Western Kenya near the Lake Victoria, severe soil erosion occurred and it thought to relate to vegetation degradation caused by overgrazing. The livestock density estimated by analyzing sa...In the study area located in Western Kenya near the Lake Victoria, severe soil erosion occurred and it thought to relate to vegetation degradation caused by overgrazing. The livestock density estimated by analyzing satellite image (1.39 TLU/ha for available grazing lands) was lower than that of measured for seven farmers’ grazing lands using GPSs (4.41 TLU/ha, 2011) with variation from 0.83 to 12.36 TLU/ha. Thus, it is clear that the grasslands used by farmers are limited compared with the area of estimated available land for grazing identified by analyzing the satellite image. According to growth-consumption rate model that was developed by the Nyangito et al. (2008) in southeastern Kenya, if livestock density reaches over 7 TLU/ha, pasture growth rate became lower than consumption rate. Grass biomasses of the grazing lands were kept low (less than 50 g/50 × 50 cm2) under high livestock density (three farmers out of seven were higher than 7 TLU/ha). In addition, rainfall pattern is very unstable and we observed stunted growth of grasses during dry spells. Therefore, we concluded that overgrazing. It means that inhibition of continuous re-growth of grasses due to high grazing pressure has been occurred even for small area and contributed to the soil erosion.展开更多
Sahel of Africa is one of the most seriously desertified regions in the world. It becomes notorious owing to severe drought anddesertification occurred during 1968-1973 in the region. This paperdiscusses the causes an...Sahel of Africa is one of the most seriously desertified regions in the world. It becomes notorious owing to severe drought anddesertification occurred during 1968-1973 in the region. This paperdiscusses the causes and essence of desertification in Sahel. Firstiy, thechanges of social and economic conditions in West Africa and theirinfluence on desertification are analysized. Then the pattem ofdesertification is described, and the causes and essence are interpreted.Finally, the author proposes some measures for prevation and control of desertification in the area.展开更多
As a result of overgrazing and deforestation in the mid-1950s, along with the advent of global warming, China is now affected by deforestation as it is impacting 400 million people. Researchers estimate that this scou...As a result of overgrazing and deforestation in the mid-1950s, along with the advent of global warming, China is now affected by deforestation as it is impacting 400 million people. Researchers estimate that this scourge costs the Chinese Government 213 billion yuan ($31 billion) a year. However, China is also the first nation to see the vast swathes of its desert lands decline by more than 2,400 square km a year.Achieving this impressive feat is in large part due to the Kubuqi model of desertification control. The Kubuqi Desert of "Yellow Peril," as it is colloquially called, is located in the Hanggin Banner of Ordos City, the Inner Mongolia Autonomous Region in north China, covering an area of 18,600 square km. This makes it the seventh largest desert in China. Yet despite the often negative connotations of arid lands, today's Kubuqi is a symbol of life, development and hope.展开更多
Rangelands worldwide have been subject to broadscale modification,such as widespread predator control,intro-duction of permanent livestock water and altered vegetation to improve grazing.In Australia,these landscape ch...Rangelands worldwide have been subject to broadscale modification,such as widespread predator control,intro-duction of permanent livestock water and altered vegetation to improve grazing.In Australia,these landscape changes have resulted in kangaroos(i.e.large macropods)populations increasing over the past 200 years.Kan-garoos are a key contributor to total grazing pressure and in conjunction with livestock and feral herbivores have been linked to land degradation.We used 22 years of aerial survey data to investigate whether the density of 3 macropod species in the southern rangelands of Western Australia was associated with:(i)land use,including type of livestock,total livestock,density of feral goats,type of land tenure,and kangaroo commercial harvest effort;(ii)predator management,including permitted dingo control effort,estimated dingo abundance,and presence of the State Barrier Fence(a dingo exclusion fence);and(iii)environmental variables:ruggedness,rainfall,fractional cover,and total standing dry matter.Red kangaroos(Osphranter rufus)were most abundant inflat,open vegetation,on pastoral land,where area permitted for dingo control was high,and numbers were positively associated with antecedent rainfall with a 12-month delay.Western grey kangaroos(Macropus fuliginosus)were most abundant onflat,agricultural land,but less abundant in areas with high permitted dingo control.Euros(Osphranter robustus)were most abundant in rugged pastoral land with open vegetation,where permitted dingo control was high.While environmental variables are key drivers of landscape productivity and kangaroo populations,anthropogenic factors such as land use and permitted dingo control are strongly associated with kangaroo abundance.展开更多
Background:Due to the effects of climate change and overgrazing in recent decades,alternative stable states in the alpine Kobresia meadow degradation process have coexisted in the same geographical and climatic enviro...Background:Due to the effects of climate change and overgrazing in recent decades,alternative stable states in the alpine Kobresia meadow degradation process have coexisted in the same geographical and climatic environment,with variations occurring among microsites.Methods:We used a space-for-time substitution approach to explore the synergies of microsite variation according to its numerical characteristics and the proportion of each stable state at various stages of succession in alpine Kobresia meadows on the Qinghai-Tibetan Plateau.Results:(1)The highest average aboveground biomass in summer was 196.2±20.3 gm^(-2),with significantly higher levels of biomass in≤3.65 sheep unit ha^(-1) than in other levels of grazing intensity,while the parameters showed no significant differences among grazing intensity levels in>3.65 sheep unit ha^(-1).(2)The importance of plant functional groups,aboveground biomass,and niche breadth of Poaceae and Cyperaceae significantly decreased as the grazing intensity increased.(3)The effects of≥0°C accumulated temperature,total precipitation,altitude,longitude,and latitude cumulatively contributed less than 20%of the variation in the distribution of functional group characteristics across microsites.Conclusions:(1)Overgrazing decreases primary production in alpine Kobresia meadows,but ecosystem responses regulate plant community structure and botanical components so as to partially counteract grazing disturbance.(2)Overgrazing changed the proportion of microsites,which in turn led to regime shift in the plant community and subsequent synergies between the microsites of plant communities and their stable states.展开更多
Background Alveolar echinococcosis is a major zoonosis of public health significance in western China. Overgrazing was recently assumed as a potential risk factor for transmission of alveolar echinococcosis. The resea...Background Alveolar echinococcosis is a major zoonosis of public health significance in western China. Overgrazing was recently assumed as a potential risk factor for transmission of alveolar echinococcosis. The research was designed to further test the overgrazing hypothesis by investigating how overgrazing influenced the burrow density of intermediate host small mammals and how the burrow density of small mammals was associated with dog Echinococcus multilocularis infection. Methods The study sites were chosen by previous studies which found areas where the alveolar echinococcosis was prevalent. The data, including grass height, burrow density of intermediate host small mammals, dog and fox fecal samples as well as Global Positioning System (GPS) position, were collected from field investigations in Shiqu County, Sichuan Province, China. The fecal samples were analyzed using copro-PCR. The worms, teeth, bones and hairs in the fecal samples were visually examined. Single factor and multifactor analyses tools including chi square and generalized linear models were applied to these data. Results By using grass height as a proxy of grazing grass in the pasture led to lower small mammals' pressure in the homogenous pasture, this study found that taller burrow density (X2=4.670, P=0.031, coefficient=-1.570). The Echinococcus multilocularis worm burden in dogs was statistically significantly related to the maximum density of the intermediate host Ochotona spp. (X2=5.250, P=-0.022, coefficient=0.028). The prevalence in owned dogs was positively correlated to the number of stray dogs seen within a 200 meter radius (Wald X2=8.375, P=-0.004, odds ratio=1.198). Conclusions Our findings support the hypothesis that overgrazing promotes transmission of alveolar echinococcosis and confirm the role of stray dogs in the transmission of alveolar echinococcosis.展开更多
Changing environmental and socio-economic conditions make land degradation,a major concern in Central and East Asia.Globally satellite imagery,particularly Normalized Difference Vegetation Index(NDVI)data,has proved a...Changing environmental and socio-economic conditions make land degradation,a major concern in Central and East Asia.Globally satellite imagery,particularly Normalized Difference Vegetation Index(NDVI)data,has proved an effective tool for monitoring land cover change.This study examines 33 grassland water points using vegetation field studies and remote sensing techniques to track desertification on the Mongolian plateau.Findings established a significant correlation between same-year field observation(line transects)and NDVI data,enabling an historical land cover perspective to be developed from 1998 to 2006.Results show variable land cover patterns in Mongolia with a 16%decrease in plant density over the time period.Decline in cover identified by NDVI suggests degradation;however,continued annual fluctuation indicates desertificationirreversible land cover changehas not occurred.Further,in situ data documenting greater cover near water points implies livestock overgrazing is not causing degradation at water sources.In combination of the two research methodsremote sensing and field surveysstrengthen findings and provide an effective way to track desertification in dryland regions.展开更多
The main grassland plain of Nech Sar National Park(NSNP)is a federally managed protected area in Ethiopia designated to protect endemic and endangered species.However,like other national parks in Ethiopia,the park has...The main grassland plain of Nech Sar National Park(NSNP)is a federally managed protected area in Ethiopia designated to protect endemic and endangered species.However,like other national parks in Ethiopia,the park has experienced significant land cover change over the past few decades.Indeed,the livelihoods of local populations in such developing countries are entirely dependent upon natural resources and,as a result,both direct and indirect anthropogenic pressures have been placed on natural parks.While previous research has looked at land cover change in the region,these studies have not been spatially explicit and,as a result,knowledge gaps in identifying systematic transitions continue to exist.This study seeks to quantify the spatial extent and land cover change trends in NSNP,identify the strong signal transitions,and identify and quantify the location of determinants of change.To this end,the author classifies panchromatic aerial photographs in 1986,multispectral SPOT imagery in 2005,and Sentinel imagery in 2019.The spatial extent and trends of land cover change analysis between these time periods were conducted.The strong signal transitions were systematically identified and quantified.Then,the basic driving forces of the change were identified.The locations of these transitions were also identified and quantified using the spatially explicit statistical model.The analysis revealed that over the past three decades(1986–2019),nearly 52%of the study area experienced clear landscape change,out of which the net change and swap change attributed to 39%and 13%,respectively.The conversion of woody vegetation to grassland(~5%),subsequently grassland-to-open-overgrazed land(28.26%),and restoration of woody vegetation(0.76%)and grassland(0.72%)from riverine forest and open-overgrazed land,respectively,were found to be the fully systematic transitions whereas the rest transitions were recorded either partly systematic or random transitions.The location of these most systematic land cover transitions identified through the spatially explicit statistical modeling showed drivers due to biophysical conditions,accessibility,and urban/market expansions,coupled with successive government policies for biodiversity management,geo-politics,demographic,and socioeconomic factors.These findings provide important insights into biodiversity loss,land degradation,and ecosystem disruption.Therefore,the model for predicted probability generally suggests a 0.75 km and 0.72 km buffers which are likely to protect forest and grassland from conversion to grassland and open-overgrazed land,respectively.展开更多
Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock...Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock overgrazing,climate change and overpopulation of small mammals are treated as important factors that cause the degradation of meadow ecosystems in the QTP.However,there are few hypotheses focus on the potential role of plant compensatory growth on meadow degradation.We proposed a compensatory growth-related hypothesis to understand the potential degradation process of meadow ecosystems in the QTP.We discussed that there are two stages of meadow degradation,i.e.the beginning stage of meadow degradation that is triggered by high-strength overcompensation;and the intensification stage of meadow degradation,which are driven by external factors such as climate warming,small mammals and thawing of permafrost.The mechanism of meadow degradation driven by plant compensatory growth is the asynchronism of plant consumption and the availability of soil nutrients.Our hypothesis that plant compensatory growth drives meadow degradation under the overgrazing condition requires re-examination and modification by testing the balance between soil nutrient cycling rates and the strength of plant compensatory growth in alpine regions.展开更多
This study was conducted in the Banni region of the Gujarat State,India,which is located in the western-most end of the country.The main objective was to investigate the local perceptions of grassland change,regenerat...This study was conducted in the Banni region of the Gujarat State,India,which is located in the western-most end of the country.The main objective was to investigate the local perceptions of grassland change,regeneration potentiality,socio-economic status and fac-tors that cause degradation of the vegetation resources in Banni.Participatory Rural Appraisal(PRA)was employed to generate the socio-economic profile of interviewed villages or hamlets.Information on vegetation deteriora-tion and changes in species composition significant for sustainable management of grassland was obtained through interviews with 51 elderly maldharies(pastoral-ists)and local inhabitants living in 31 villages in Banni.Local people had observed a change in the local surrounding habitats from grassland to woodland(domi-nated by Prosopis juliflora,locally called Gando Bavar)during their lifetime and considered it primarily a result of frequent intensive drought,constructed dams on flooding rivers in Banni,and declining rainfall.The socio-economic survey showed that the Banni communities are highly dependent on the natural grassland for various purposes.In particular,nine woody species were useful for construction of the traditional house called Bhunga,four for medicine and 22 for livestock fodder.Highly preferred and declining species were characteristically large wild thorny trees with edible fruits,viz.Acacia nilotica subsp.indica(Bavar),Prosopis cineraria(Kandho),and Salvadora persica(Kharijar).Some of the locally highly preferred grass species were also considered to be declining in the local environs;they included Dichanthium annulatum(Jinjvo),Cenchrus ciliaris(Dhaman),Sporobolus fertilis(Khevai)and Chloris barbata(Siyarpuchha).The study furthermore identified a close coincidence between the interest in conserving tree species diversity nearby the natural water resources and priorities of local inhabitants,which included protection of plenty of large trees(including many fruit tress,viz.Mangifera indicia(Ambo),Cordia dichotoma(Gunda)and Pithecellobium dulce(Gora-samli)),improvement of woody fodder tree and grass species regeneration,and reduction of overgrazing pres-sure on grasslands.Focusing management strategies on increasing the populations of such declining and highly preferred tree and grass species,by active restoration and grazing policies,would enhance the natural resource value and biodiversity wealth considerably and thereby the quality of life for the local inhabitants.The implications of the results are discussed and recommendations are suggested for conservation,management,and sustainable utilization of the fragile grassland ecosystem of the Banni region.展开更多
文摘The soil constituents and relations between the variation of soil resources and plant communities in three adjacent sites representing the overgrazing, reclamation and comparatively undisturbed communities respectively were quantified and examined in study area in Huailai Basin, Hebei Province, China. There have been significantly greater constituent of C, N, P in the soils of shrubland site. Corg, Ntotal, Navail and Pavail were between 1.18 and 3.90 times more concentrated in the soils of shrubland site in comparison with the other two sites. Although the Ptotal concentration was lower in shrubland soils than in overgrazed rangeland soils, the Pavail concentration, however, was significantly greater in the soils of shrubland site, and increased by 59.1% and even 289.6% in the soils of shrubland site comparing to those in the soils of range-land and millet field sites. Among the three sites, CV exceeding 40% were found for SO4, Cl, and F ion. The CV of organic carbon also exceeded 40% but only in the soils of millet field site. The highest CV were found for F, SO4 ion in the soils of shrubland and overgrazed rangeland sites, while for Cl and SO4 ion in those of millet field site. The results also showed that the introductions of shrubs are of vital importance for the accumulation of soil nutrients and maintenance of soil fertilities, and also for the restoration and reconstruction of desertified ecosystems.
文摘ALASHAN AND ORDOS,Inner Mongolia-Dust,five centimeters thick, and rat holes cover the landscape of the Shilekai village,about 300 kilometers from the city of Ordos, Inner Mongolia.
基金the Health Department of Sichuan Province the Ecology of Infectious Diseases Program from USA National Institutes of Health (No. 1565)the French Embassy in Beijing
文摘Background Overgrazing was assumed to increase the population density of small mammals that are the intermediate hosts of Echinococcus multilocularis, the pathogen of alveolar echinococcosis in the Qinghai Tibet Plateau. This research tested the hypothesis that overgrazing might promote Echinococcus multilocularis transmission through increasing populations of small mammal, intermediate hosts in Tibetan pastoral communities. Methods Grazing practices, small mammal indices and dog Echinococcus multilocularis infection data were collected to analyze the relation between overgrazing and Echinococcus multilocularis transmission using nonparametric tests and multiple stepwise logistic regression. Results In the investigated area, raising livestock was a key industry. The communal pastures existed and the available forage was deficient for grazing. Open (common) pastures were overgrazed and had higher burrow density of small mammals compared with neighboring fenced (private) pastures; this high overgrazing pressure on the open pastures measured by neighboring fenced area led to higher burrow density of small mammals in open pastures. The median burrow density of small mammals in open pastures was independently associated with nearby canine Echinococcus multilocularis infection (P=-0.003, OR=1.048). Conclusion Overgrazing may promote the transmission of Echinococcus multilocularis through increasing the population density of small mammals.
基金The Chinese National Non-profit Program for Environment Protection,No.201109030
文摘The Three-River Headwaters region in China is an ecological barrier providing en- vironmental protection and regional sustainable development for the mid-stream and down- stream areas, which also plays an important role in animal husbandry in China. This study estimated the grassland yield in the Three-River Headwaters region based on MODIS NPP data, and calculated the proper livestock-carrying capacity of the grassland. We analyzed the overgrazing number and its spatial distribution characteristics through data comparison be- tween actual and proper livestock-carrying capacity. The results showed the following: (1) total grassland yield (hay) in the Three-River Headwaters region was 10.96 million tons in 2010 with an average grassland yield of 465.70 kg/hm2 (the spatial distribution presents a decreasing trend from the east and southeast to the west and northwest in turn); (2) the proper livestock-carrying capacity in the Three-River Headwaters region is 12.19 million sheep units (hereafter described as "SU"), and the average stocking capacity is 51.27 SU [the proper carrying capacity is above 100 SU/km2 in the eastern counties, 60 SU/km2 in the cen- tral counties (except Madoi County), and 30 SU/km2 in the western counties]; and (3) total overgrazing number was 6.52 million SU in the Three-River Headwaters region in 2010, with an average overgrazing ratio of 67.88% and an average overgrazing number of 27.43 SU/km2 A higher overgrazing ratio occurred in Tongde, Xinghai, Yushu, Henan and Z^kog. There was no overgrazing in Zhiduo, Tanggula Township and Darlag, Qumerleb and Madoi. The re- mainder of the counties had varying degrees of overgrazing.
基金financially supported by the Hundred Talent Program of Chinese Academy of Sciences and the National Natural Science Foundation of China (41301211, 41201195)
文摘Climate warming and livestock grazing are known to have great influences on alpine ecosystems like those of the Qinghai-Tibetan Plateau (QTP) in China. However, it is lacking of studies on the effects of warming and grazing on plant and soil properties in these alpine ecosystems. In this study, we reported the related research from manipulative experiment in 2010-2012 in the QTP. The aim of this study was to investigate the individual and combined effects of warming and clipping on plant and soil properties in the alpine meadow ecosystem. Infrared radiators were used to simulate climate warming starting in July 2010, while clipping was performed once in Octo- ber 2011 to simulate the local livestock grazing. The experiment was designed as a randomized block consisting of five replications and four treatments: control (CK), warming (W), clipping (C) and warming+clipping combination (WC). The plant and soil properties were investigated in the growing season of the alpine meadow in 2012. The results showed that W and WC treatments significantly decreased relative humidity at 20-cm height above ground as well as significantly increases air temperature at the same height, surface temperature, and soil temperature at the depth of 0-30 cm. However, the C treatment did not significantly decrease soil moisture and soil temperature at the depth of 0-60 cm. Relative to CK, vegetation height and species number increased significantly in W and WC treatment, respectively, while vegetation aboveground biomass decreased significantly in C treatment in the early growing season. However, vegetation cover, species diversity, belowground biomass and soil properties at the depth of 0-30 cm did not differ significantly in W, C and WC treatments. Soil moisture increased at the depth of 40-100 cm in W and WC treatments, while belowground biomass, soil activated carbon, organic carbon and total nitrogen increased in the 30-50 cm soil layer in W, C and WC treatments. Although the initial responses of plant and soil properties to experimental warming and clipping were slow and weak, the drought induced by the down- ward shift of soil moisture in the upper soil layers may induce plant belowground biomass to transfer to the deeper soil layers. This movement would modify the distributions of soil activated carbon, organic carbon and total nitrogen However, long-term data collection is needed to further explain this interesting phenomenon.
基金supported by the National Basic Research Program of China (2014CB138806)the International Science and Technology Cooperation Project of China (2013DFR30760)+1 种基金the Natural Science Foundation Committee of Inner Mongolia, China (ZD201502)the Basic Research Funding Project of Institute of Grassland Research, Chinese Academy of Agricultural Sciences (1610332015005)
文摘St udying the changes in nutrient use strategies induced by grazing can provide insight into the process of grassland degradation and is important for improving grassland quality and enhancing ecosystem function. Dominant species in meadow steppe can optimize their use of limiting resources; however, the regulation of nutrient use strategies across grazing gradients is not fully understood. Therefore, in this study, we report an in situ study in which the impact of grazing rates on nutrient use strategies of Leymus chinensis, the dominant plant species in eastern Eurasian temperate steppes, was investigated. We conducted a large randomized controlled experiment(conducted continuously for five years in grassland plots in a natural pasture in Ha ilar, eastern Mongolia Plateau, China) to assess the effects of grazing rate treatments(0.00, 0.23, 0.34, 0.46, 0.69, and 0.92 adult cattle unit(AU) ha-1) on L. chinensis along a grazing gradient and employed a random sampling approach to compare the accumulation, allocation, and stoichiometry of C, N, and P in leaves and stems. Ou r findings demonstrated the follows:(i) The height of L. chinensis decreased with an increase in the grazing gradient, and the concentrations of C, N, and P significantly increased;(ii) the accumulation of C, N, and P per individual was negatively correlated with the concentration of aboveground tissues, suggesting that there was a tradeoff in L. chinensis between nutrient accumulation and concentration at the individual scale;(iii) the leaf-to-stem ratio of C, N, and P accumulation increased with grazing intensity, indicating a tradeoff in nutrient allocation and plant size at the individual plant level; and(iv) grazing rates were negatively correlated with the ratios of C:N and C:P in the stem; however, these ratios in leaves significantly increased with grazing intensity. Our findings suggest that L. chinensis in meadow steppe adapts to grazing disturbance through tradeoffs between plant size and nutrient use strategies. Moreover, our results imply that grazing produces a compensatory effect on nutrient use efficiency between the stems and leaves of L. chinensis.
基金the Asian Development Bank,the International Center for Agricultural Research in the Dry Areas,Russian Scientific Fund(14-38-00023)the CGIAR Research Program on Dryland Systems for their support and funding
文摘Rangelands of Central Asia (referring to Kazakhstan, Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan in this study), the largest contiguous area of grazed land in the world, serve as an important source of livelihood for pastoral and agro-pastoral communities in this region. They also play an important role in absorbing CO<sub>2</sub> as a global carbon sink. However, unsustainable management of rangelands has led to their degradation hugely by downgrading their potential agro-ecological, environmental and socio-economical roles. This paper reviewed the rangeland degradation in Central Asia, a topic which so far has received only scant coverage in the international scientific literature. It also provided examples of successful experiences and outlined possible options that land managers can adopt to enhance the sustainable management of these vast degraded rangelands. The experiences and lessons described in this paper may also be relevant for other degraded rangeland areas, especially in the developing countries. The causes of rangeland degradation within the Central Asian region are numerous, complex and inter-related. Therefore, while addressing the factors associated with improper rangeland management may shed some light on the causes of rangeland degradation, the scope of this paper would not be all-encompassing for the major causes of degradation. There is a need to develop and widely apply the viable and locally accepted and adapted packages of technical, institutional and policy options for sustainable rangeland management. Incentivizing the collective action of small-scale pastoralists who group together to facilitate access to remote pastures can reduce the degree of overgrazing within community pastures, such as those near the settlements. We also found that migratory grazing through pooling of resources among small-scale pastoralists can increase household income. After their independence, most Central Asian countries adopted various rangeland tenure arrangements. However, the building of enhanced capacities of pasture management and effective local rangeland governance structures can increase the likelihood, which will be sustainable and equitable. Finally, this paper presented several promising technical options, aiming at reversing the trend of rangeland degradation in Central Asia.
基金supported by the National Natural Science Foundation of China(4090104931060060)+1 种基金the Major State Basic Research Development Program of China(2009CB 421303)the 'Qing Lan' Talent Engineering Funds of Lanzhou Jiaotong University(QL-08-14A)
文摘Horqin Sandy Land is a fragile, seriously desertified region located in Inner Mongolia of China. Over- grazing is one of the primary drivers of desertification in this region. We investigated whether the establishment of grazing exclosures in areas with active sand dunes enhances soil carbon (C) sequestration and benefits soil re- covery. The results showed that soil organic C storage was 1.4, 1.9, and 3.5 times, and light fraction C storage was 2.3, 3.2, and 4.4 times in the 100-cm topsoil after 7, 12, and 25 years of grazing exclusion, respectively, compared to the case in active sand dunes. The light fraction of soil played an important role in soil C sequestration, although it might not change rapidly to provide an early indication of how soil C is increasing in response to grazing exclusion. The results indicated that soils could potentially sequester up to 13.8 Mt C in 25 years if active sand dunes in the study area were to be protected by exclosures. This corresponds to 12.8% of the estimated carbon loss (107.53 Mt) that has been associated with desertification over the past century in the Horqin Sandy Land. Our results suggested that exclosures have the capacity to increase soil C sequestration; however, decades will be required for soil C to recover to historical grassland levels observed prior to desertification.
文摘We undertook ethnobotanical study of forage/fodder plant species used by the Afar and Oromo (Kereyu and lttu) Nations in and around the semi=arid Awash National Park (ANP), Ethiopia. The study aimed at investigating and documenting indigenous knowledge (IK) on forage/fodder plant species and threats to their survival. Ninety-six in= formants between 20 and 80 years old were selected using prior informa- tion. Data were collected using semi-structured interview, guided field wail discussion and field observation. Preference ranking, Jaccard's coefficient of similarity and priority ranking were used for data analysis. One hundred twenty-six forage/fodder species of 90 genera and 43 fami- lies were collected in the study area. More than 88% of the species were reported with their vernacular names, where 68% were reported by the Afar Nation and 70% by the Oromo Nation. Family Poaceae was repre- sented by 25 species (20%), followed by Fabaceae 18 (14%). Preference ranking for the most preferred forage grasses as perceived by key informants revealed that Chrysopogon plumulosus was the most important forage/fodder species. Overgrazing was the major threat in the study area, scoring 22%.
文摘In the study area located in Western Kenya near the Lake Victoria, severe soil erosion occurred and it thought to relate to vegetation degradation caused by overgrazing. The livestock density estimated by analyzing satellite image (1.39 TLU/ha for available grazing lands) was lower than that of measured for seven farmers’ grazing lands using GPSs (4.41 TLU/ha, 2011) with variation from 0.83 to 12.36 TLU/ha. Thus, it is clear that the grasslands used by farmers are limited compared with the area of estimated available land for grazing identified by analyzing the satellite image. According to growth-consumption rate model that was developed by the Nyangito et al. (2008) in southeastern Kenya, if livestock density reaches over 7 TLU/ha, pasture growth rate became lower than consumption rate. Grass biomasses of the grazing lands were kept low (less than 50 g/50 × 50 cm2) under high livestock density (three farmers out of seven were higher than 7 TLU/ha). In addition, rainfall pattern is very unstable and we observed stunted growth of grasses during dry spells. Therefore, we concluded that overgrazing. It means that inhibition of continuous re-growth of grasses due to high grazing pressure has been occurred even for small area and contributed to the soil erosion.
文摘Sahel of Africa is one of the most seriously desertified regions in the world. It becomes notorious owing to severe drought anddesertification occurred during 1968-1973 in the region. This paperdiscusses the causes and essence of desertification in Sahel. Firstiy, thechanges of social and economic conditions in West Africa and theirinfluence on desertification are analysized. Then the pattem ofdesertification is described, and the causes and essence are interpreted.Finally, the author proposes some measures for prevation and control of desertification in the area.
文摘As a result of overgrazing and deforestation in the mid-1950s, along with the advent of global warming, China is now affected by deforestation as it is impacting 400 million people. Researchers estimate that this scourge costs the Chinese Government 213 billion yuan ($31 billion) a year. However, China is also the first nation to see the vast swathes of its desert lands decline by more than 2,400 square km a year.Achieving this impressive feat is in large part due to the Kubuqi model of desertification control. The Kubuqi Desert of "Yellow Peril," as it is colloquially called, is located in the Hanggin Banner of Ordos City, the Inner Mongolia Autonomous Region in north China, covering an area of 18,600 square km. This makes it the seventh largest desert in China. Yet despite the often negative connotations of arid lands, today's Kubuqi is a symbol of life, development and hope.
文摘Rangelands worldwide have been subject to broadscale modification,such as widespread predator control,intro-duction of permanent livestock water and altered vegetation to improve grazing.In Australia,these landscape changes have resulted in kangaroos(i.e.large macropods)populations increasing over the past 200 years.Kan-garoos are a key contributor to total grazing pressure and in conjunction with livestock and feral herbivores have been linked to land degradation.We used 22 years of aerial survey data to investigate whether the density of 3 macropod species in the southern rangelands of Western Australia was associated with:(i)land use,including type of livestock,total livestock,density of feral goats,type of land tenure,and kangaroo commercial harvest effort;(ii)predator management,including permitted dingo control effort,estimated dingo abundance,and presence of the State Barrier Fence(a dingo exclusion fence);and(iii)environmental variables:ruggedness,rainfall,fractional cover,and total standing dry matter.Red kangaroos(Osphranter rufus)were most abundant inflat,open vegetation,on pastoral land,where area permitted for dingo control was high,and numbers were positively associated with antecedent rainfall with a 12-month delay.Western grey kangaroos(Macropus fuliginosus)were most abundant onflat,agricultural land,but less abundant in areas with high permitted dingo control.Euros(Osphranter robustus)were most abundant in rugged pastoral land with open vegetation,where permitted dingo control was high.While environmental variables are key drivers of landscape productivity and kangaroo populations,anthropogenic factors such as land use and permitted dingo control are strongly associated with kangaroo abundance.
基金National Natural Science Foundation of China,Grant/Award Number:U20A2006Youth Project of Qinghai Province,Grant/Award Number:2023-ZJ-967Q Abstract。
文摘Background:Due to the effects of climate change and overgrazing in recent decades,alternative stable states in the alpine Kobresia meadow degradation process have coexisted in the same geographical and climatic environment,with variations occurring among microsites.Methods:We used a space-for-time substitution approach to explore the synergies of microsite variation according to its numerical characteristics and the proportion of each stable state at various stages of succession in alpine Kobresia meadows on the Qinghai-Tibetan Plateau.Results:(1)The highest average aboveground biomass in summer was 196.2±20.3 gm^(-2),with significantly higher levels of biomass in≤3.65 sheep unit ha^(-1) than in other levels of grazing intensity,while the parameters showed no significant differences among grazing intensity levels in>3.65 sheep unit ha^(-1).(2)The importance of plant functional groups,aboveground biomass,and niche breadth of Poaceae and Cyperaceae significantly decreased as the grazing intensity increased.(3)The effects of≥0°C accumulated temperature,total precipitation,altitude,longitude,and latitude cumulatively contributed less than 20%of the variation in the distribution of functional group characteristics across microsites.Conclusions:(1)Overgrazing decreases primary production in alpine Kobresia meadows,but ecosystem responses regulate plant community structure and botanical components so as to partially counteract grazing disturbance.(2)Overgrazing changed the proportion of microsites,which in turn led to regime shift in the plant community and subsequent synergies between the microsites of plant communities and their stable states.
文摘Background Alveolar echinococcosis is a major zoonosis of public health significance in western China. Overgrazing was recently assumed as a potential risk factor for transmission of alveolar echinococcosis. The research was designed to further test the overgrazing hypothesis by investigating how overgrazing influenced the burrow density of intermediate host small mammals and how the burrow density of small mammals was associated with dog Echinococcus multilocularis infection. Methods The study sites were chosen by previous studies which found areas where the alveolar echinococcosis was prevalent. The data, including grass height, burrow density of intermediate host small mammals, dog and fox fecal samples as well as Global Positioning System (GPS) position, were collected from field investigations in Shiqu County, Sichuan Province, China. The fecal samples were analyzed using copro-PCR. The worms, teeth, bones and hairs in the fecal samples were visually examined. Single factor and multifactor analyses tools including chi square and generalized linear models were applied to these data. Results By using grass height as a proxy of grazing grass in the pasture led to lower small mammals' pressure in the homogenous pasture, this study found that taller burrow density (X2=4.670, P=0.031, coefficient=-1.570). The Echinococcus multilocularis worm burden in dogs was statistically significantly related to the maximum density of the intermediate host Ochotona spp. (X2=5.250, P=-0.022, coefficient=0.028). The prevalence in owned dogs was positively correlated to the number of stray dogs seen within a 200 meter radius (Wald X2=8.375, P=-0.004, odds ratio=1.198). Conclusions Our findings support the hypothesis that overgrazing promotes transmission of alveolar echinococcosis and confirm the role of stray dogs in the transmission of alveolar echinococcosis.
文摘Changing environmental and socio-economic conditions make land degradation,a major concern in Central and East Asia.Globally satellite imagery,particularly Normalized Difference Vegetation Index(NDVI)data,has proved an effective tool for monitoring land cover change.This study examines 33 grassland water points using vegetation field studies and remote sensing techniques to track desertification on the Mongolian plateau.Findings established a significant correlation between same-year field observation(line transects)and NDVI data,enabling an historical land cover perspective to be developed from 1998 to 2006.Results show variable land cover patterns in Mongolia with a 16%decrease in plant density over the time period.Decline in cover identified by NDVI suggests degradation;however,continued annual fluctuation indicates desertificationirreversible land cover changehas not occurred.Further,in situ data documenting greater cover near water points implies livestock overgrazing is not causing degradation at water sources.In combination of the two research methodsremote sensing and field surveysstrengthen findings and provide an effective way to track desertification in dryland regions.
文摘The main grassland plain of Nech Sar National Park(NSNP)is a federally managed protected area in Ethiopia designated to protect endemic and endangered species.However,like other national parks in Ethiopia,the park has experienced significant land cover change over the past few decades.Indeed,the livelihoods of local populations in such developing countries are entirely dependent upon natural resources and,as a result,both direct and indirect anthropogenic pressures have been placed on natural parks.While previous research has looked at land cover change in the region,these studies have not been spatially explicit and,as a result,knowledge gaps in identifying systematic transitions continue to exist.This study seeks to quantify the spatial extent and land cover change trends in NSNP,identify the strong signal transitions,and identify and quantify the location of determinants of change.To this end,the author classifies panchromatic aerial photographs in 1986,multispectral SPOT imagery in 2005,and Sentinel imagery in 2019.The spatial extent and trends of land cover change analysis between these time periods were conducted.The strong signal transitions were systematically identified and quantified.Then,the basic driving forces of the change were identified.The locations of these transitions were also identified and quantified using the spatially explicit statistical model.The analysis revealed that over the past three decades(1986–2019),nearly 52%of the study area experienced clear landscape change,out of which the net change and swap change attributed to 39%and 13%,respectively.The conversion of woody vegetation to grassland(~5%),subsequently grassland-to-open-overgrazed land(28.26%),and restoration of woody vegetation(0.76%)and grassland(0.72%)from riverine forest and open-overgrazed land,respectively,were found to be the fully systematic transitions whereas the rest transitions were recorded either partly systematic or random transitions.The location of these most systematic land cover transitions identified through the spatially explicit statistical modeling showed drivers due to biophysical conditions,accessibility,and urban/market expansions,coupled with successive government policies for biodiversity management,geo-politics,demographic,and socioeconomic factors.These findings provide important insights into biodiversity loss,land degradation,and ecosystem disruption.Therefore,the model for predicted probability generally suggests a 0.75 km and 0.72 km buffers which are likely to protect forest and grassland from conversion to grassland and open-overgrazed land,respectively.
基金This work was supported by the National Natural Science Foundation of China[31901394]the Second Tibetan Plateau Scientific Expedition and Research[2019QZKK0307]Young Elite Scientists Sponsorship Program by CAST[2019QNRC001].
文摘Degradation of meadow ecosystems in the largest alpine region of the world,i.e.,the Qinghai-Tibetan Plateau(QTP),is a crucial ecological issue that has ardently discussed in recent years.Many factors,such as livestock overgrazing,climate change and overpopulation of small mammals are treated as important factors that cause the degradation of meadow ecosystems in the QTP.However,there are few hypotheses focus on the potential role of plant compensatory growth on meadow degradation.We proposed a compensatory growth-related hypothesis to understand the potential degradation process of meadow ecosystems in the QTP.We discussed that there are two stages of meadow degradation,i.e.the beginning stage of meadow degradation that is triggered by high-strength overcompensation;and the intensification stage of meadow degradation,which are driven by external factors such as climate warming,small mammals and thawing of permafrost.The mechanism of meadow degradation driven by plant compensatory growth is the asynchronism of plant consumption and the availability of soil nutrients.Our hypothesis that plant compensatory growth drives meadow degradation under the overgrazing condition requires re-examination and modification by testing the balance between soil nutrient cycling rates and the strength of plant compensatory growth in alpine regions.
文摘This study was conducted in the Banni region of the Gujarat State,India,which is located in the western-most end of the country.The main objective was to investigate the local perceptions of grassland change,regeneration potentiality,socio-economic status and fac-tors that cause degradation of the vegetation resources in Banni.Participatory Rural Appraisal(PRA)was employed to generate the socio-economic profile of interviewed villages or hamlets.Information on vegetation deteriora-tion and changes in species composition significant for sustainable management of grassland was obtained through interviews with 51 elderly maldharies(pastoral-ists)and local inhabitants living in 31 villages in Banni.Local people had observed a change in the local surrounding habitats from grassland to woodland(domi-nated by Prosopis juliflora,locally called Gando Bavar)during their lifetime and considered it primarily a result of frequent intensive drought,constructed dams on flooding rivers in Banni,and declining rainfall.The socio-economic survey showed that the Banni communities are highly dependent on the natural grassland for various purposes.In particular,nine woody species were useful for construction of the traditional house called Bhunga,four for medicine and 22 for livestock fodder.Highly preferred and declining species were characteristically large wild thorny trees with edible fruits,viz.Acacia nilotica subsp.indica(Bavar),Prosopis cineraria(Kandho),and Salvadora persica(Kharijar).Some of the locally highly preferred grass species were also considered to be declining in the local environs;they included Dichanthium annulatum(Jinjvo),Cenchrus ciliaris(Dhaman),Sporobolus fertilis(Khevai)and Chloris barbata(Siyarpuchha).The study furthermore identified a close coincidence between the interest in conserving tree species diversity nearby the natural water resources and priorities of local inhabitants,which included protection of plenty of large trees(including many fruit tress,viz.Mangifera indicia(Ambo),Cordia dichotoma(Gunda)and Pithecellobium dulce(Gora-samli)),improvement of woody fodder tree and grass species regeneration,and reduction of overgrazing pres-sure on grasslands.Focusing management strategies on increasing the populations of such declining and highly preferred tree and grass species,by active restoration and grazing policies,would enhance the natural resource value and biodiversity wealth considerably and thereby the quality of life for the local inhabitants.The implications of the results are discussed and recommendations are suggested for conservation,management,and sustainable utilization of the fragile grassland ecosystem of the Banni region.