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61.
Clem Tisdell 《Biodiversity and Conservation》1994,3(5):419-436
The main characteristics of the dominant economic system, including the increasing use of markets and money are described. The global system has expanded trade, including international trade, and production tremendously. While this system has the potential to favour nature conservation, in practice the opposite has occurred. Difficulties raised for conservation of biodiversity by short-term economic crises such as deficits in a country's international payments, the adoption of policies for structural economic adjustment, international capital flows, international loans and foreign aid as well as debt-for-nature swaps are discussed. As explained, it is politically difficult in market economies to support nature conservation at the expense of economic growth and as more economies develop and become market economies this problem spreads. Given global interdependence of nations, an important issue is the distribution of net benefits from biodiversity conservation between developed and less developed countries. Possible distributions of benefits and related issues are discussed. In conclusion, the importance of political lobbying by nature conservation groups in developed market economies is emphasised as a means of ensuring correction of market failures. Unfortunately, no economic system is likely to prove satisfactory in itself in conserving biodiversity so political action by conservationists is always required. 相似文献
62.
M. A. Burgess 《Biodiversity and Conservation》1994,3(2):126-136
Understanding the relationships between indigenous people and their threatened economic plants can aid the conservation effort on many levels. Understanding ethnic perceptions of the taxon is critical toin situ andex situ conservation projects and enhances the accompanying educational effort. Examples are discussed from the experience of a grassroots conservation group in southwestern United States, Native Seed/SEARCH. Four levels of economic plant vulnerability are examined among 1) wild-harvested plants, 2) husbanded wild plants, 3) domesticates, and 4) wild relatives of domesticates. Legal interpretations of endangered husbanded and domestic plants are discussed, and further documentation encouraged. Genetic dynamism of threatened indigenous crops is examined and the concept of Systems Conservation (i.e. the plant/human interactive systems) is introduced. Guidelines are offered for incorporating better cultural responsibility intoex situ conservation strategies. The concept of Biocultural Restoration is introduced with an example from an O'odham community. Examples are given of ways indigenous peoples and their knowledge can assist in the conservation effort. 相似文献
63.
评世界保护联盟新的物种受威胁分类系统草案 总被引:2,自引:0,他引:2
王献溥 《植物资源与环境学报》1994,3(4):55-58
为了进一步了解物种受威胁的情况和发展,以加强物种保护工作,世界保护联盟制定了一个新的物种受威胁分类系统草案,把物种受威胁的程度分为9个级别,即绝灭种、野生状态下的绝灭种、极危种、濒危种、渐危种、敏感种、安全的/危险性小的种、不充分了解的种和未估价的种。本文对这个分类系统草案作了简略的评介。 相似文献
64.
An ecosystems approach to base-rich freshwater wetlands,with special reference to fenlands 总被引:1,自引:1,他引:0
Geert van Wirdum 《Hydrobiologia》1993,265(1-3):129-153
A survey of base-rich wetlands in The Netherlands is presented. The main area of their occurrence is the low-lying Holocene
part of the country, until some thousand years ago a large and coherent wetland landscape: the Holland wetland. The development
of various parts of the Holland wetland into marshes, fens and bogs can be understood from hydrological relations in mire
basins, as recognized in the distinction of primary, secondary and tertiary mire basin stages. Presently, the remnants of
the Holland wetland are separate base-rich wetlands. The succession of their vegetation reflects various abiotic conditions
and human influences. Three main developmental periods are distinguished as regards these factors. The first, geological period
of mire development is seen as a post-glacial relaxation, with the inertia due to the considerable mass of wetland as a stabilizing
factor. Biological “grazing” influences, as an aspect of utilization by humans, converted base-rich wetlands to whole new
types in the second, historical period. Presently, mass and harvesting have decreased in importance, and actual successions
in terrestrializing turbaries seem to reflect rapidly changing environmental conditions. Human control could well become the
most important factor in the future development of wetland nature. The present value of open fen vegetation strongly depends
on the continuation of the historical harvesting. The development of wooded fen may help to increase the mass of wetland in
the future. Best results in terms of biodiversity are expected when their base state is maintained through water management.
The vegetation and hydrology of floating fens in terrestrializing turbaries is treated in some more detail. Various lines
and phases in the succession are distinguished. Open fen vegetation at base-rich, yet nutrient-poor sites is very rich in
species threatened elsewhere. The fast acidification of certain such fens is attributed to hydrological and management factors.
This acidification is illustrated in the profile of a floating raft sample. At the scale of these small fens, the elemental
structure comprising base-rich fen, transitional fen and bog vegetation, is not as stable as it was in the large Holland wetland.
A critical role seems to be played by the supply of bases with the water influx. The changing base state is supposed to change
the nutrient cycling to such an extent that it would be correct to call this trophic excitation of the ecosystem, rather than
just eutrophication. Eutrophication indicates a quantitative reaction to an increased nutrient supply, the internal system
being unaltered. The drainage of fens, resulting in an increased productivity of the vegetation, provides another example
of excitation, to the effect that the functional system is dramatically changed internally. 相似文献
65.
The densities of alkali fly larvae and pupae were measured in relation to depth and substrate type at six locations around Mono Lake. Samples representing a mixture of different bottom features were taken to a depth of 10 m (33 ft) using SCUBA. This is at or near the depth limit of fly larvae and pupae. The biomass of larvae and pupae on hard substrate were maximum and approximately equal at depths of 0.5 m and 1 m, substantially lower at intermediate depths of 3 m and 5 m, and over an order of magnitude further reduced at 10 m. Densities of flies on hard or rocky substrates (mainly calcareous tufa deposits), were significantly greater than those found on soft substrates such as mud or sand, at all but the greatest depth surveyed.Bathymetric maps of the areas of hard and soft substrate occurring at different lake depths were used to estimate the fly population size over the whole lake, based on the density distribution of larvae and pupae with depth on different substrates. The mapped areas of soft and hard substrates were also calculated for different lake levels, and applying the same procedure, a population model comparing the abundance of flies at different lake levels was developed. This habitat-based population model predicts that the abundance of the alkali fly is maximized at 6380 ft (1945 m) lake surface elevation. Most of the tufa substrate submerged at this lake level will become exposed and unavailable as habitat as the lake declines to 6370 ft (1942 m). In late 1991, the lake level was just over 6374 ft (1943 + m). 相似文献
66.
Evaluation of five strategies for obtaining a core subset from a large genetic resource collection of durum wheat 总被引:6,自引:0,他引:6
P. L. Spagnoletti Zeuli C. O. Qualset 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(3):295-304
The use of plant genetic resources contained in a large collection may be enhanced by specifying subsamples, called core samples. Five strategies for selecting a core sample from a collection of 3000 durum wheat accessions were applied and evaluated using four qualitative and eight quantitative spike characters. Each of the following strategies generated about 500 accessions for the core sample: random, random-systematic according to chronology of entry of the accessions into the collection, stratified by countryof-origin, stratified by log frequency by country-of-origin, and stratified by canonical variables. The first three strategies produced samples representative of the whole collection, but the remaining two produced the desired effect of increasing frequencies from less-represented countries-of-origin for several characters. The stratified canonical sample increased phenotypic variances. The quality of core samples is dependent upon good passport and evaluation data to partition the collection. The multivariate approach is extremely useful, but requires considerable data from the whole collection. Ecogeographic origin may be used in the absence of evaluation data on several characters to select useful core samples. 相似文献
67.
Niclas U. Lundsgaard Coen Hird Kathleen A. Doody Craig E. Franklin Rebecca L. Cramp 《Global Change Biology》2023,29(14):3857-3868
Ecological carryover effects, or delayed effects of the environment on an organism's phenotype, are central predictors of individual fitness and a key issue in conservation biology. Climate change imposes increasingly variable environmental conditions that may be challenging to early life-history stages in animals with complex life histories, leading to detrimental physiological and fitness effects in later life. Yet, the latent nature of carryover effects, combined with the long temporal scales over which they can manifest, means that this phenomenon remains understudied and is often overlooked in short-term studies limited to single life-history stages. Herein, we review evidence for the physiological carryover effects induced by elevated ultraviolet radiation (UVR; 280–400 nm) as a potential contributor to recent amphibian population declines. UVR exposure causes a suite of molecular, cellular and physiological consequences known to underpin carryover effects in other taxa, but there is a lack of research linking embryonic and larval UVR exposures to fitness consequences post-metamorphosis in amphibians. We propose that the key impacts of UVR on disease-related amphibian declines are facilitated through carryover effects that bridge embryonic and larval UVR exposure with potential increased disease susceptibility post-metamorphosis. We conclude by identifying a practical direction for the study of ecological carryover effects in amphibians that could guide future ecological research in the broader field of conservation physiology. Only by addressing carryover effects can many of the mechanistic links between environmental change and population declines be elucidated. 相似文献
68.
Ana Buchadas Martin Jung Mercedes Bustamante Álvaro Fernández-Llamazares Stephen T. Garnett Ana Sofía Nanni Natasha Ribeiro Patrick Meyfroidt Tobias Kuemmerle 《Global Change Biology》2023,29(17):4880-4897
Tropical and subtropical dry woodlands are rich in biodiversity and carbon. Yet, many of these woodlands are under high deforestation pressure and remain weakly protected. Here, we assessed how deforestation dynamics relate to areas of woodland protection and to conservation priorities across the world's tropical dry woodlands. Specifically, we characterized different types of deforestation frontier from 2000 to 2020 and compared them to protected areas (PAs), Indigenous Peoples' lands and conservation areas for biodiversity, carbon and water. We found that global conservation priorities were always overrepresented in tropical dry woodlands compared to the rest of the globe (between 4% and 96% more than expected, depending on the type of conservation priority). Moreover, about 41% of all dry woodlands were characterized as deforestation frontiers, and these frontiers have been falling disproportionately in areas with important regional (i.e. tropical dry woodland) conservation assets. While deforestation frontiers were identified within all tropical dry woodland classes of woodland protection, they were lower than the average within protected areas coinciding with Indigenous Peoples' lands (23%), and within other PAs (28%). However, within PAs, deforestation frontiers have also been disproportionately affecting regional conservation assets. Many emerging deforestation frontiers were identified outside but close to PAs, highlighting a growing threat that the conserved areas of dry woodland will become isolated. Understanding how deforestation frontiers coincide with major types of current woodland protection can help target context-specific conservation policies and interventions to tropical dry woodland conservation assets (e.g. PAs in which deforestation is rampant require stronger enforcement, inactive deforestation frontiers could benefit from restoration). Our analyses also identify recurring patterns that can be used to test the transferability of governance approaches and promote learning across social–ecological contexts. 相似文献
69.
Erik Joaquín Torres-Romero Vincent Nijman David Fernández Timothy M. Eppley 《Global Change Biology》2023,29(20):5775-5787
The world's primates have been severely impacted in diverse and profound ways by anthropogenic pressures. Here, we evaluate the impact of various infrastructures and human-modified landscapes on spatial patterns of primate species richness, at both global and regional scales. We overlaid the International Union for the Conservation of Nature (IUCN) range maps of 520 primate species and applied a global 100 km2 grid. We used structural equation modeling and simultaneous autoregressive models to evaluate direct and indirect effects of six human-altered landscapes variables (i.e., human footprint [HFP], croplands [CROP], road density [ROAD], pasture lands [PAST], protected areas [PAs], and Indigenous Peoples' lands [IPLs]) on global primate species richness, threatened and non-threatened species, as well as on species with decreasing and non-decreasing populations. Two-thirds of all primate species are classified as threatened (i.e., Critically Endangered, Endangered, and Vulnerable), with ~86% experiencing population declines, and ~84% impacted by domestic or international trade. We found that the expansion of PAST, HFP, CROP, and road infrastructure had the most direct negative effects on primate richness. In contrast, forested habitat within IPLs and PAs was positively associated in safeguarding primate species diversity globally, with an even stronger effect at the regional level. Our results show that IPLs and PAs play a critical role in primate species conservation, helping to prevent their extinction; in contrast, HFP growth and expansion has a dramatically negative effect on primate species worldwide. Our findings support predictions that the continued negative impact of anthropogenic pressures on natural habitats may lead to a significant decline in global primate species richness, and likely, species extirpations. We advocate for stronger national and international policy frameworks promoting alternative/sustainable livelihoods and reducing persistent anthropogenic pressures to help mitigate the extinction risk of the world's primate species. 相似文献
70.
David Storch Jaroslav Koleček Petr Keil Zdeněk Vermouzek Petr Voříšek Jiří Reif 《Diversity & distributions》2023,29(4):572-585