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1.
对本实验室分离到的一株中度嗜盐菌Halomonas sp.NY-011的耐盐特性和耐盐机理进行了初步研究.NY-011在LB培养基中最大能耐受260g/LNaCl浓度,在M63培养基中能耐受大于150g/LNaCl浓度.Cl-的缺少对NY-011的耐盐生长有明显抑制,K+较Li+和Mg2+更适合于为NY-011提供内部渗透压力.NY-011通过在胞内积累K+、游离氨基酸及其他相容性溶质对抗胞外渗透压力.NY-011胞内相容性溶质组成随培养基NaCl浓度变化而变化,四氢嘧啶是最主要的组成成分,含量随培养基NaCl浓度增加而增加,120g/LNaCl时浓度可达到71.5mg/g干重.NY-011还可吸收胞外的四氢嘧啶和甜菜碱以平衡外界高渗透压.随着培养基中NaCl浓度的提高,NY-011菌体蛋白的合成受到明显抑制.图5表2参24  相似文献   

2.
从采自内蒙古锡林浩特地区盐湖的样品中筛选到产脂肪酶嗜盐菌JNPH-3,该菌株可在含有1.5~5mol/L NaCl的培养基上生长,最适生长温度45℃,最适pH7~9.5.经形态学分析、生理生化实验及16SrDNA鉴定,JNPH-3菌株为Halorubrum aidingense,属于极端嗜盐菌.JNPH-3菌株在生长过程中专一性依赖Na+,对Cl-依赖性较小,K+浓度变化对菌体生长无明显影响.高效液相色谱分析表明,JNPH-3菌株在液体复合培养基中能够产生四氢嘧啶,且与环境中盐浓度呈负相关,说明JNPH-3体内除存在产生四氢嘧啶的机制来维持渗透平衡,还有其它机制来维持细胞正常生长.  相似文献   

3.
一株积聚四氢嘧啶的青海湖盐单胞菌的分离及特性   总被引:1,自引:0,他引:1  
从青海湖采集20份水样,利用RM高盐培养基分离获得35株嗜盐菌.选取其中一株优势中度嗜盐菌QHL25进行形态学和生理生化特征分析,结果表明:QHL25菌落圆形或椭圆形,乳白色,不透明,中心突出,边缘透明,生长盐度为0~2.9 mol/L,最适生长盐度为1.45 mol/L.显微形态呈短杆状,革兰氏染色呈阴性,单个或成串排列.最适生长pH为8.5,最适生长温度为37℃.16S rDNA序列分析表明:该菌株与盐单胞菌属(Halomonas sp.)相似性为98%;结合形态特征和生理生化特征分析,初步认定该菌株隶属于γ变形杆菌纲(Gammaproteobacteria)海洋螺菌目(Oceanospirillales)盐单胞菌科(Holomonadaceae)盐单胞菌属(Holomonas).薄层层析(TLC)定性分析可知QHL25胞内含有相容溶质四氢嘧啶;高效液相色谱(HPLC)定量分析表明,在1.7 mol/L的NaCl浓度下,四氢嘧啶含量约为36.70 mg/g(细胞干重).  相似文献   

4.
水中主要阳离子对铜绿微囊藻生长及多糖的影响   总被引:2,自引:0,他引:2  
郭丽丽  朱伟  李明 《生态环境》2013,(8):1358-1364
通过室内培养试验,在65μmol·m-2·s-1光照度和12 h∶12 h光暗比下,模拟野外水体中铜绿微囊藻(Microcystis aeruginosa)的生长,研究了水中主要阳离子Ca、Mg、K、Na质量浓度的变化对铜绿微囊藻生长以及多糖的影响。依据自然水体中Ca、Mg、K、Na的实际浓度水平结合已有研究得到的抑制浓度,试验分别设定了5个质量浓度梯度的培养基,其中Ca质量浓度梯度为0、10、20、50、100 mg·L-1,Mg质量浓度梯度为0、2、5、10、20 mg·L-1,K质量浓度梯度为5、10、20、50、100 mg·L-1,Na质量浓度梯度为18、30、50、100、200 mg·L-1。试验测定的生理生化指标包括培养周期内每天铜绿微囊藻的藻细胞密度和对数生长期内铜绿微囊藻溶解性胞外多糖(sEPS)、固着性胞外多糖(bEPS)和胞内多糖(IPS)的含量。试验结果表明:低质量浓度的Ca对微囊藻的生长没有明显影响,高质量浓度的Ca(〉50 mg·L-1)会抑制铜绿微囊藻的生长但同时铜绿微囊藻合成多糖总量(TPS)会增加,Ca质量浓度的增大对铜绿微囊藻胞外多糖的分泌呈现先促进后抑制的趋势,并在刺激铜绿微囊藻细胞分泌多糖的同时会促进其溶解。Mg缺失时,铜绿微囊藻的生长会受到显著的抑制,较高质量浓度的Mg(〉5 mg·L-1)也会抑制铜绿微囊藻的生长但同时铜绿微囊藻合成多糖总量(TPS)会增加,Mg在适宜质量浓度(5 mg·L-1)会抑制多糖分泌、防止多糖溶解。K离子质量浓度的变化对微囊藻的生长无明显影响但铜绿微囊藻TPS的量呈现先增加后减少的趋势,K对多糖的分泌并没有显著影响,但对多糖的溶解呈现先促进后抑制的作用。Na离子质量浓度的变化对铜绿微囊藻的生长以及合成TPS的量均无明显影响,Na质量浓度增大对多糖的分泌的影响与Ca的一致,但影响的程度明显小于Ca的影响,其质量浓度的增加对多糖的溶解过程有轻微的促进作用。  相似文献   

5.
由ectA、ectB、ectC和ectD编码的酶可以催化对细胞起保护作用的四氢嘧啶类物质的生物合成,嗜盐菌新种Halomonas socia NY-011~T ectABC和ectD为四氢嘧啶和羟基四氢嘧啶的生产提供新的基因来源.通过SEFA-PCR步移方法从Halomonas socia NY-011~T中克隆ectA、ectB、ectC和ectD基因,并分别构建ectABC和ectD的原核表达质粒,在E.coli BL21(DE3)中异源表达,利用SDS-PAGE对重组蛋白进行鉴定,通过ACQUITY UPLC MS/MS检测四氢嘧啶和羟基四氢嘧啶的生成.结果显示:H.socia NY-011~T的四氢嘧啶合成基因ectA、ectB、ectC形成基因簇ectABC(KP717055-57),大小为2 506 bp,四氢嘧啶羟化酶基因ectD大小为942 bp(KP717058),与近源种H.elongata DSM258同源性分别为81%和78%;SDS-PAGE检测到4种融合蛋白,大小(M_r)分别为21.6×10~3、46.4×10~3、14.4×10~3、55.3×10~3,与预期相符;利用ACQUITY UPLC MS/MS发现仅表达ectABC的重组菌株[E.coli BL21(DE3)/pltac-ABC]中只存在四氢嘧啶,而在表达ectABC和ectD的重组菌株[E.coli BL21(DE3)/pltac-ABC/pETect D]中检测到四氢嘧啶和羟基四氢嘧啶.本研究从H.socia NY-011~T中分离得到的四氢嘧啶类物质的合成基因,能够在E.coli BL21(DE3)中异源表达并行使功能,为四氢嘧啶类物质异源生产提供了新的基因来源.  相似文献   

6.
从20份青海湖水样中,分离获得了35株中度嗜盐菌株.耐盐梯度实验表明:水体中以中度嗜盐菌为主,约占65.7%;弱嗜盐菌次之,约占25.7%;非嗜盐菌与耐盐菌相对较少,约占8.5%.采用80%乙醇法抽提中度嗜盐菌胞内的Ectoine,利用TLC和HPLC分析,结果表明:青海湖中度嗜盐菌中,大多数胞内积聚相溶物质Ectoine;在最适生长盐度下,中度嗜盐菌QHL1、QHL5、QHL10、QHL26和QHL28的胞内Ectoine含量分别为258.6μg·mL-1、325.47μg·mL-1、208.8μg·mL-1、292.31μg·mL-1和295.13μg·mL-1,以此初步获得5株具有Ectoine高产潜力的野生菌株.  相似文献   

7.
α-MnO2/水界面磺胺嘧啶的氧化降解动力学   总被引:2,自引:0,他引:2  
通过反歧化法合成α-MnO2,并以α-MnO2为氧化剂,研究了不同锰氧化物剂量、不同磺胺嘧啶初始浓度和不同pH值下α-MnO2/水界面磺胺嘧啶的氧化降解动力学,并讨论了不同的反应条件对反应动力学的影响.结果表明,α-MnO2可以有效的氧化降解甚至矿化磺胺嘧啶,反应符合准一级反应动力学方程,在25 ℃,pH 4.6的反应条件下,反应120 min后,11.5 mmol·L-1的α-MnO2对0.02 mmol·L-1磺胺嘧啶去除率达到99.98%.α-MnO2剂量和磺胺嘧啶的初始浓度均与磺胺嘧啶氧化降解的动力学常数呈显著正相关关系,相关因子分别为0.67和0.18,相关系数R分别达到0.9961和0.9979;而磺胺嘧啶的降解动力学常数与体系的pH则呈显著负相关关系,相关因子为-0.25,相关系数R达到0.9975.初步探讨了锰氧化物氧化降解磺胺嘧啶机理.研究表明,土壤及沉积物中的锰氧化物可以有效促进其中残留抗生素类药物磺胺嘧啶的降解消除过程.  相似文献   

8.
青海湖嗜盐菌的分离与优势菌株QHL5的特性   总被引:1,自引:0,他引:1  
采用高盐选择性培养基从20份青海湖水样中筛选分离获得35株青海湖嗜盐微生物.耐盐梯度实验分析表明:水体中以中度嗜盐菌为主,约占65.7%;弱嗜盐菌次之,约占25.7%;非嗜盐菌与耐盐菌相对较少,约占8.5%.其中优势菌QHL5的生长盐度耐受范围为0.04~3.0 mol/L,最适生长范围为0.3~0.9 mol/L,隶属于中度嗜盐菌.菌体形态和生长特性分析表明:QHL5菌落大小为4~6 mm,圆形或椭圆形,边缘整齐厚实,乳白色,中间微隆起,不透明,革兰氏染色阴性.显微形态呈杆状,最适生长pH为8.5~9.5,最适生长温度为35℃.生理生化、16S rRNA的全序列Blast和系统发育分析表明:QHL5菌株分类定位于γ变形菌纲海洋螺菌目盐单胞菌属樊氏盐单胞菌(Halomonas ventosae).通过80%乙醇法抽提胞内相溶物质,采用TLC法检测出该菌积聚四氢嘧啶.  相似文献   

9.
为研究日喀则不同粒径大气颗粒物中水溶性无机离子的组成特征,利用Andersen分级撞击式采样器在夏、冬季进行大气颗粒物分级采样,采用离子色谱测定NH+4、Ca2+、K+、Mg2+、Na+、SO2-4、NO-3和Cl-等8种离子浓度.结果表明,夏、冬季总离子浓度分别为9648±3030、4925±1138 ng·m-3.夏季离子浓度高低顺序为Cl-﹥Ca2+﹥NH+4﹥Na+﹥SO2-4﹥NO-3﹥K+﹥Mg2+,Cl-、Ca2+、NH+4和Na+占总离子浓度的比重为74.9%;冬季水溶性无机离子浓度高低顺序为Cl-﹥SO2-4﹥NH+4﹥NO-3﹥Ca2+﹥Na+﹥K+﹥Mg2+,Cl-、SO2-4、NH+4和NO-3占总离子浓度的比重为88.0%.夏、冬季大气颗粒物中所有水溶性无机离子的粒径分布均成双峰型.夏季,大气颗粒物中SO2-4与Mg2+(r=0.951)、Ca2+(r=0.947),NO-3与Mg2+(r=0.904)、Ca2+(r=0.843),在0.01水平(双侧)上均显著相关;冬季,细粒子中K+与Cl-(r=0.740)、SO2-4(r=0.929)及NO-3(r=0.920),在0.01水平(双侧)上显著相关.  相似文献   

10.
水体中微污染磺胺嘧啶药物的氧化降解   总被引:2,自引:0,他引:2  
环境中残留的微量抗生素药物对生态环境的危害和修复越来越受到人们的重视.对广泛使用的广谱抗菌素磺胺嘧啶(SD)微污染水体的Fenton氧化降解进行了研究,探讨了SD、H2O2、Fe2+质量浓度、pH和反应时间对SD降解率的影响.研究结果表明,当SD初始质量浓度为2.0 mg·L-1,水体中添加H2O2、Fe2+至质量浓度分别为30 mg·L-1和1.25 mg·L-1,反应时间为60 min时,降解率可以达到99.8%,说明Fenton法是一种有效的处理微量磺胺嘧啶带来的水体污染的修复方法.  相似文献   

11.
Conservation science is a crisis discipline in which the results of scientific enquiry must be made available quickly to those implementing management. We assessed the extent to which scientific research published since the year 2000 in 20 conservation science journals is publicly available. Of the 19,207 papers published, 1,667 (8.68%) are freely downloadable from an official repository. Moreover, only 938 papers (4.88%) meet the standard definition of open access in which material can be freely reused providing attribution to the authors is given. This compares poorly with a comparable set of 20 evolutionary biology journals, where 31.93% of papers are freely downloadable and 7.49% are open access. Seventeen of the 20 conservation journals offer an open access option, but fewer than 5% of the papers are available through open access. The cost of accessing the full body of conservation science runs into tens of thousands of dollars per year for institutional subscribers, and many conservation practitioners cannot access pay‐per‐view science through their workplace. However, important initiatives such as Research4Life are making science available to organizations in developing countries. We urge authors of conservation science to pay for open access on a per‐article basis or to choose publication in open access journals, taking care to ensure the license allows reuse for any purpose providing attribution is given. Currently, it would cost $51 million to make all conservation science published since 2000 freely available by paying the open access fees currently levied to authors. Publishers of conservation journals might consider more cost effective models for open access and conservation‐oriented organizations running journals could consider a broader range of options for open access to nonmembers such as sponsorship of open access via membership fees. Obtención de Acceso Abierto a la Ciencia de la Conservación  相似文献   

12.
Summary Interactions were studied among alkaloid-containing legumes (Erythrina corallodendrum andSpartium junceum) and non-toxic plants (Citrus sinensis, Cucurbita moschata andEuphorbia tirucalli), several polyphagous homopterans,Aphis craccivora (Aphididae),Icerya purchasi, I. aegyptiaca (Margarodidae),Lepidosaphes ulmi (Diaspididae) andPlanococcus citri (Pseudococcidae), and some major natural enemies of these homopterans. Significant reductions in survival due to negative effects of alkaloid containing as compared with non-alkaloidal plants were recorded for the predatorsRodolia cardinalis andChilocorus bipustulatus, but not forCryptolaemus montrouzieri (Coleoptera: Coccinellidae),Chrysoperla carnea (Neuroptera: Chrysopidae) andSympherobius sanctus (Neuroptera: Sympherobiidae). The development time of the larvae or pupae ofR. cardinalis, C. carnea andS. sanctus was longer on the toxic plants than on the non-toxic ones. The percentage of parasitism ofA. craccivora collected from the non-alkaloidal plantsVicia palaestina andMelilotus albus was much higher than that onS. junceum. The parasitoid complexes ofA. craccivora differed between both plant groups. The nutritive value of honeydew ofI. purchasi andA. craccivora, as expressed by the life span ofEncyrtus infelix (Hymenoptera: Encyrtidae) adults, was also investigated. Life spans were significantly longer when the wasps fed on honeydew produced on non-alkaloidal plants (C. sinensis andPittosporum tobira) than on alkaloid containing plants whenI. purchasi — but notA. craccivora — was the producer. It is suggested that the chemical defense ofE. corallodendrum andS. junceum is exploited by polyphagous phytophages to reduce predation. In nature, population growth and density of four of the investigated homopterans are conspicuously high when they developed on the alkaloid containing plant species, and very low on non-alkaloid plants. The efficiency of their natural enemies may be reduced by sequestration of alkaloids (or other toxic plant compounds) or their transfer into excreted honeydew. Therefore it is assumed that a generalist phytophagous homopteran may be protected from its natural enemies, although at different rates of efficiency, if it can safely sequester the host allelochemical when it develops on toxic species within its host range.  相似文献   

13.
A bioblitz inexpensively and quickly generates biodiversity data, but bioblitzes are often conducted with haphazard, unreplicated sampling. Results tend to be taxonomically, geographically, or temporally biased, lack metadata, and consist of lists of observed taxa that do not enable further analyses or correction for imperfect detection. A rapid, recurring, structured survey (RRSS) uses a structured sampling design and temporal and spatial replication to survey randomly selected sites on a conservation property. We participated in a loosely structured bioblitz and a subsequent RRSS at Big Canoe Creek Nature Preserve in Springville (St. Clair County), Alabama (USA) to compare observed richness derived from the 2 survey approaches. The RRSS data structure enabled us to fit models that accounted for imperfect detection to estimate abundances, occupancy probabilities, and habitat associations. The loosely structured bioblitz data could not be used in such models. We present a new integrated multispecies abundance model that we applied to avian RRSS data. Our model extension enables estimation for the community, employs data augmentation to estimate the number of undetected species, and incorporates covariates. The RRSS generated a more comprehensive and less biased list of observed taxonomic richness than the loosely structured bioblitz (e.g., 73 vs. 45 bird species and 104 vs. 63 insect families from the RRSS vs. loosely structured bioblitz, respectively). Models fit to the RRSS data identified seasonal patterns in avian community composition and allowed for estimation of habitat–occupancy relationships for insect taxa. The RRSS protocol has potential for broad transferability as a standardized, quick, and inexpensive way to inventory biodiversity and estimate ecological parameters while providing an outreach opportunity.  相似文献   

14.
Summary Two South American polyphagous leaf beetles,Diabrotica speciosa andCerotoma arcuata, selectively accumulated the bitter tasting compound 23,24-dihydrocucurbitacin D in their body after ingesting root tissues of cucurbit plants. Similarly, three Asian Cucurbitaceae-feeding specialists in the genusAulacophora were found to sequester the same compound. Cucurbitacin analogs were shown to deter feeding by a bird predator, indicating an allomonal role for these compounds in cucurbitacin-associated chrysomelid leaf beetles both of New and Old Worlds. The strong affinity to cucurbitacins, selective sequestration of the analogs and consequent protection from predators suggested an ecological adaptation mechanism developed in common among these two geographically isolated subtribes in the Luperini.  相似文献   

15.
Abstract: In East Africa fire and grazing by wild and domestic ungulates maintain savannas, and pastoralists historically set fires and herded livestock through the use of temporary corrals called bomas. In recent decades traditional pastoral practices have declined, and this may be affecting biodiversity. We investigated the effects of prescribed fires and bomas on savanna bird communities in East Africa during the first and second dry seasons of the year (respectively before and after the rains that mark the onset of breeding for most birds). We compared abundance, richness, and community composition on 9‐ha burned plots, recently abandoned bomas, and control plots in the undisturbed matrix habitat over a 3‐year period. Generally, recently burned areas and abandoned bomas attracted greater densities of birds and had different community assemblages than the surrounding matrix. The effects of disturbances were influenced by interactions between primary productivity, represented by the normalized difference vegetation index, and time. Bird densities were highest and a greater proportion of species was observed on burned plots in the months following the fires. Drought conditions equalized bird densities across treatments within 1 year, and individuals from a greater proportion of species were more commonly observed on abandoned bomas. Yearly fluctuations in abundance were less pronounced on bomas than on burns, which indicate that although fire may benefit birds in the short term, bomas may have a more‐lasting positive effect and provide resources during droughts. Several Palearctic migrants were attracted to burned plots regardless of rainfall, which indicates continued fire suppression may threaten their already‐declining populations. Most notably, the paucity of birds observed on the controls suggests that the current structure of the matrix developed as a result of fire suppression. Traditional pastoralism appears critical to the maintenance of avian diversity in these savannas.  相似文献   

16.
Land-use change via human development is a major driver of biodiversity loss. To reduce these impacts, billions of dollars are spent on biodiversity offsets. However, studies evaluating offset project effectiveness that examine components such as the overall compliance and function of projects remain rare. We reviewed 577 offsetting projects in freshwater ecosystems that included the metrics project size, type of aquatic system (e.g., wetland and creek), offsetting measure (e.g., enhancement, restoration, and creation), and an assessment of the projects’ compliance and functional success. Project information was obtained from scientific and government databases and gray literature. Despite considerable investment in offsetting projects, crucial problems persisted. Although compliance and function were related to each other, a high level of compliance did not guarantee a high degree of function. However, large projects relative to area had better function than small projects. Function improved when projects targeted productivity or specific ecosystem features and when multiple complementary management targets were in place. Restorative measures were more likely to achieve targets than creating entirely new ecosystems. Altogether the relationships we found highlight specific ecological processes that may help improve offsetting outcomes.  相似文献   

17.
An argument is presented in which areas of natural arsenic contamination of modern groundwaters throughout Asia have a common origin. Arsenic originally accumulated in oceanic ferro-manganoan sediments of the eastern Palaeo-Tethys. This was further concentrated through oceanic crustal extinction in what later became the south-east Chinese accreted mineralised terrain. Proto-Himalayan uplift of this area created the palaeo-drainage systems of the Ganges – Brahmaputra, Irrawaddy, Mekong, and Red Rivers, with consequent headwater erosion of arsenic-rich sediments. Their downstream deposition as immature and easily redistributed Neogene sandstones, silts, and iron-rich clays has created secondary and tertiary reservoirs of adsorbed and authigenic arsenic, from which the current arsenic-rich groundwaters have evolved. Considering river basins within the above palaeo-hydrogeological framework provides a basis for assessing the risk of arsenic in groundwater basins of south and south-eastern Asia.  相似文献   

18.
Abstract: The last century has seen the ascendance of a core economic model, which we will refer to as Walrasian economics. This model is driven by the psychological assumptions that humans act only in a self‐referential and narrowly rational way and that production can be described as a self‐contained circular flow between firms and households. These assumptions have critical implications for the way economics is used to inform conservation biology. Yet the Walrasian model is inconsistent with a large body of empirical evidence about actual human behavior, and it violates a number of basic physical laws. Research in behavioral science and neuroscience shows that humans are uniquely social animals and not self‐centered rational economic beings. Economic production is subject to physical laws including the laws of thermodynamics and mass balance. In addition, some contemporary economic theory, spurred by exciting new research in human behavior and a wealth of data about the negative global impact of the human economy on natural systems, is moving toward a world view that places consumption and production squarely in its behavioral and biophysical context. We argue that abandoning the straightjacket of the Walrasian core is essential to further progress in understanding the complex, coupled interactions between the human economy and the natural world. We call for a new framework for economic theory and policy that is consistent with observed human behavior, recognizes the complex and frequently irreversible interaction between human and natural systems, and directly confronts the cumulative negative effects of the human economy on the Earth's life support systems. Biophysical economics and ecological economics are two emerging economic frameworks in this movement.  相似文献   

19.
Effects of Coffee Management on Deforestation Rates and Forest Integrity   总被引:1,自引:0,他引:1  
Knowledge about how forest margins are utilized can be crucial for a general understanding of changes in forest cover, forest structure, and biodiversity across landscapes. We studied forest‐agriculture transitions in southwestern Ethiopia and hypothesized that the presence of coffee (Coffea arabica)decreases deforestation rates because of coffee's importance to local economies and its widespread occurrence in forests and forest margins. Using satellite images and elevation data, we compared changes in forest cover over 37 years (1973–2010) across elevations in 2 forest‐agriculture mosaic landscapes (1100 km2 around Bonga and 3000 km2 in Goma‐Gera). In the field in the Bonga area, we determined coffee cover and forest structure in 40 forest margins that differed in time since deforestation. Both the absolute and relative deforestation rates were lower at coffee‐growing elevations compared with at higher elevations (?10/20% vs. ?40/50% comparing relative rates at 1800 m asl and 2300–2500 m asl, respectively). Within the coffee‐growing elevation, the proportion of sites with high coffee cover (>20%) was significantly higher in stable margins (42% of sites that had been in the same location for the entire period) than in recently changed margins (0% of sites where expansion of annual crops had changed the margin). Disturbance level and forest structure did not differ between sites with 30% or 3% coffee. However, a growing body of literature on gradients of coffee management in Ethiopia reports coffee's negative effects on abundances of forest‐specialist species. Even if the presence of coffee slows down the conversion of forest to annual‐crop agriculture, there is a risk that an intensification of coffee management will still threaten forest biodiversity, including the genetic diversity of wild coffee. Conservation policy for Ethiopian forests thus needs to develop strategies that acknowledge that forests without coffee production may have higher deforestation risks than forests with coffee production and that forests with coffee production often have lower biodiversity value. Efectos de la Administración Cafetalera sobre las Tasas de Deforestación y la Integridad de los Bosques  相似文献   

20.
As drivers of terrestrial ecosystems, humans have replaced large carnivores in most areas, and human influence not only exerts striking ecological pressures on biodiversity at local scales but also has indirect effects in distant corners of the world. We suggest that the multibillion dollar cashmere industry creates economic motivations that link western fashion preferences for cashmere to land use in Central Asia. This penchant for stylish clothing, in turn, encourages herders to increase livestock production which affects persistence of over 6 endangered large mammals in these remote, arid ecosystems. We hypothesized that global trade in cashmere has strong negative effects on native large mammals of deserts and grassland where cashmere‐producing goats are raised. We used time series data, ecological snapshots of the biomass of native and domestic ungulates, and ecologically and behaviorally based fieldwork to test our hypothesis. In Mongolia increases in domestic goat production were associated with a 3‐fold increase in local profits for herders coexisting with endangered saiga (Saiga tatarica).That increasing domestic grazing pressure carries fitness consequences was inferred on the basis of an approximately 4‐fold difference in juvenile recruitment among blue sheep (Pseudois nayaur)in trans‐Himalayan India. Across 7 study areas in Mongolia, India, and China's Tibetan Plateau, native ungulate biomass is now <5% that of domestic species. Such trends suggest ecosystem degradation and decreased capacity for the persistence of native species, including at least 8 Asian endemic species: saiga, chiru (Pantholops hodgsoni), Bactrian camel (Camelus bactrianus), snow leopard(Panthera uncia), khulan(Equus hemionus), kiang (E. kiang), takhi (E. przewalski), and wild yak (Bos mutus). Our results suggest striking yet indirect and unintended actions that link trophic‐level effects to markets induced by the trade for cashmere. Globalización del Mercado de Cachemira y la Declinación de Mamíferos Mayores en Asia Central  相似文献   

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