The future of the US endangered species act

The United States Endangered Species Act of J973 (ESA) is the strongest tool for protecting plants and animals in the US and has served as a model of species protection for many other nations. Because the goals of the Act - to conserve all endangered and threatened species in the US and the ecosystems upon which they depend - are widely supported among US environmentalists and biologists, it is commonly believed that these groups offer united support for the legislation. Within the US, however, vigorous debate ensues among conservation biologists as to the effectiveness of the species-oriented approach of the Act.     

Preliminary distributional analysis of US endangered bird species

A first exploration of applications of ecological niche modeling and geographic distributional prediction to endangered species protection is developed. Foci of richness of endangered bird species are identified in coastal California and along the southern fringe of the United States. Species included on the Endangered Species List on the basis of peripheral populations inflate these concentrations considerably. Species without protection in the US National Park System are focused particularly in peninsular Florida. Application of this methodology to additional taxa and regions holds promise for diverse conservation applications.     

Whole-genome analysis of giraffe supports four distinct species

1. Download : Download high-res image (223KB)
2. Download : Download full-size image

     

Genetic admixture supports an ancient hybrid origin of the endangered Hawaiian duck

Speciation is regarded primarily as a bifurcation from an ancestral species into two distinct taxonomic units, but gene flow can create complex signals of phylogenetic relationships, especially among different loci. We evaluated several hypotheses that could account for phylogenetic discord between mitochondrial DNA (mtDNA) and nuclear DNA (nuDNA) within Hawaiian duck (Anas wyvilliana), including stochastic lineage sorting, mtDNA capture and widespread genomic introgression. Our results best support the hypothesis that the contemporary Hawaiian duck is descended from an ancient hybridization event between the mallard (Anas platyrhynchos) and Laysan duck (Anas laysanensis). Whereas mtDNA clearly shows a sister relationship between Hawaiian duck and mallard, nuDNA is consistent with a genetic mosaic with nearly equal contributions from Laysan duck and mallard. In addition, coalescent analyses suggest that gene flow from either mallard or Laysan duck, depending on the predefined tree topology, is necessary to explain contemporary genetic diversity in Hawaiian ducks, and these estimates are more consistent with ancient, rather than contemporary, hybridization. Time since divergence estimates suggest that the genetic admixture event occurred around the Pleistocene–Holocene boundary, which is further supported by circumstantial evidence from the Hawaiian subfossil record. Although the extent of reproductive isolation from either putative parental taxon is not currently known, these species are phenotypically, genetically and ecologically different, and they meet primary criteria used in avian taxonomy for species designation. Thus, the available data are consistent with an admixed origin and support the hypothesis that the Hawaiian duck may represent a young hybrid species.     

物种濒危等级划分与物种保护

介绍了国际与国内濒危物种等级最新标准。探讨了濒危物处等级的划分标准存在的问题和物种的保护优先序。介绍了确定物种保护优先序时的两种不同观点。     

Semen cryopreservation and the conservation of endangered species

Currently, more than 16,000 plant and animal species are imminently threatened by extinction, often as a direct consequence of anthropogenic influences. One of the measures to halt that process is genetic resource banking. This short review focuses on mammal sperm cryopreservation in combination with assisted reproduction techniques. It summarizes general problems, recent developments, and currently applied protocols and gives an overview of hitherto existing successes of assisted reproduction measures in wild animals in the light of conservation efforts.     

Reproductive biotechnologies for endangered mammalian species

Assisted reproductive techniques (gamete cryopreservation, artificial insemination, embryo transfer, and in vitro fertilization) allow to propagate small fragmented populations of wild endangered species or domestic breeds. There are the best way for producing several offspring from selected genitors in order to avoid inbreeding depression. However, few mammalian species have been well studied for their reproductive biology whereas huge differences have been observed between these species. Furthermore, materials, methods and experimental designs have to be adapted for each case and each limiting factor (wildness, poor quantity of biological material, disparate locations). Genome resource banking is currently arising and the most applied reproductive biotechnology remains artificial insemination. Assisted reproductive techniques currently developed in domestic species (intracytoplasmic sperm injection, nuclear transfer) may offer new opportunities for the propagation of endangered species.     

基于最受关注濒危物种分布的国家级自然保护区空缺分析

我们收集整理了中国96个最受关注濒危物种的分布点信息, 利用Maxent分布模型模拟其中分布点信息较为充分的46个物种的潜在分布区, 将其余50个分布信息极少物种的分布点直接标示在地图上。通过分析单个物种分布被国家级自然保护区覆盖的比例, 以及国家级自然保护区覆盖最受濒危物种分布热点地区的比例, 对国家级自然保护区进行了空缺分析。截至2014年底, 仅16个最受关注濒危物种的预测分布区被保护区覆盖超过10%。在分布有最受关注濒危物种的数目可能超过10种的像元(0.8421º)中, 仅有8.27%得到国家级自然保护区保护; 另外, 仅有10.9%的最受关注濒危哺乳动物分布热点地区、1.13%的最受关注濒危鸟类分布热点地区和7.26%的最受关注濒危植物分布热点地区得到国家级自然保护区覆盖。结果显示国家级自然保护区对大部分最受关注濒危物种覆盖不足, 尤其是对其中的所有长距离迁徙鸟类; 国家级自然保护区对最受关注濒危物种分布热点地区覆盖也不足, 尤其是在中国东部和南部地区, 自然保护区在这些地区的布局亟待优化。     

Managerial strategies in the captive propagation of endangered species

A captive propagation manager, committed to the welfare of captive populations of exotic animals, must often make decisions that are risky to individual animals. Innovative decisions that place animals at risk are essential to the progress of captive propagation. Such decisions must be grounded thoroughly on peer consultation, the scientific and zoo literature, and where possible on original applied research targeted specifically to the procedure in question. The management of two closely spaced births in a gorilla group is provided as an example.     

Chemical constituents of the Korean endangered species Rhododendron brachycarpum

1. Download : Download full-size image

     

Habitat loss and the limits to endangered species recovery

Canada is one of the last places on earth with extensive wilderness areas, yet the number of Canadian species threatened with extinction continues to rise every year. Using satellite‐derived land use data, we find that habitat loss explains most of the variation in numbers of endangered species across Canada. Habitat loss within species ranges is, therefore, likely to be the leading factor inhibiting their recovery. We measured habitat loss individually within the known ranges of 243 terrestrial species at risk of extinction across Canada. Recovery potential, as measured by extent of natural habitat within each species’ range, is bimodally distributed, but less than 50% of the range of the majority of Canada's species at risk is natural habitat and there is no detectable habitat remaining for 16 of the 243 species at risk. There were no differences in the recovery potential of species categorized either by threat level (special concern, threatened, or endangered) or taxon. Despite having extensive wilderness areas, Canada has similar rates of endangerment to other countries in the Americas, underlining the effect of severe habitat loss to intensive agriculture that has occurred in Canada's most biologically diverse regions. Improvements to protected areas networks and especially cooperative conservation activities with private landowners will do the most to improve the recovery prospects of species at risk in Canada.     

Measuring progress in US endangered species conservation

Since passage of the Endangered Species Act in 1973, over 1300 endangered and threatened species have been protected in the USA and its territories. Most species continue to face a significant risk of extinction, but the status of many species is improving. Here we present analyses of federal agency reports to the United States Congress (1988–2002) that describe differences in species status and show which variables are correlated with improving or declining status. We found that 52% of species showed repeated improvements or were not declining over this time. Species status improves over time, with only 35% still declining 13 years or more after protection. Taxonomy, funding by US Fish and Wildlife Service and National Oceanic and Atmospheric Administration, and agency assessment of risk of extinction and potential to recover were significantly correlated with status.     

黄土高原不同气象因子对中国沙棘亚居群遗传多样性的影响

顶生金花茶(Camellia terminalis)是一种濒危植物,主要分布在广西天等县石灰岩山钙质土上的常绿阔叶林内.采用样地调查、统计分析和回归模型预测等方法,对顶生金花茶种群的分布环境、资源量现状、大小和高度结构等进行了研究.结果表明:该种群主要依存于天等县小山乡的蚬木-石山樟林(P1)和任豆-蚬木林(P2)、福新乡的枝花李榄-石山楠林(P3)和齿叶大风子-闭花木林(P4)4种群落,构成灌木层的优势种和共优种;P1、P3和P4种群处于群落较稳定的典型常绿季雨林中,结构较完整,属于稳定或增长型;P2种群由于恶劣环境和频繁人为干扰的共同胁迫,有衰退的趋势;与小山乡生境相比,福新乡相对冷凉湿润的气候条件、丰厚肥沃的土层以及较轻度的人为干扰有利于顶生金花茶种群的发展.目前顶生金花茶种群的资源量有限,建议列为"严重濒临灭绝"(CR)等级.     

The great scallop: an endangered species

The great scallop is a highly valued marine species. It makes its home on rocky seabeds around the British Isles and has been heavily exploited. Fears that natural stocks are showing signs of over fishing are being remedied by strict enforcement of fisheries legislation and by the development of stock enhancement practices.