共查询到20条相似文献,搜索用时 15 毫秒
1.
D. Delille 《Biodiversity and Conservation》1996,5(11):1505-1523
A short overview of the biodiversity of Antarctic marine bacteria is given with respect to morphology and metabolic activity. The importance of spatial and temporal variability is described. The physiological adaptation and ecological function of Antarctic marine bacterioplankton are discussed. 相似文献
2.
The pycnogonids of the Southern Ocean have been studied for almost two centuries and have played a key role in shaping previous biogeographic regions for the Antarctic benthos. The aim of this study was to assess the biogeographic patterns derived from the most current sample records of pycnogonids from the Southern Ocean and neighbouring areas. 332 species of pycnogonids from 1837 sample locations were analysed using 279 3° by 3° grid cells. We investigated richness patterns and the effect of sampling intensity at both local and regional scales, and used multivariate analysis of distribution patterns and species assemblages to define biogeographic trends. These analyses identified a distinct and isolated Antarctic pycnogonid shelf fauna which was different to that of the deep‐sea around Antarctica, the Sub‐Antarctic islands, South America or New Zealand. Within the Antarctic, we found the South Shetland Islands to be the most speciose region and a probable center of radiation for the pycnogonids. No latitudinal gradients in species richness were detected. We note that the distribution patterns observed are based upon classical taxonomy and discuss the potential for changes to these patterns with new insights from molecular techniques. We conclude that, even with the potential for cryptic species, the large‐scale biogeographic trends observed in the pycnogonids should hold true. 相似文献
3.
Laurence Cordonnery 《Ocean Development & International Law》2013,44(3):188-207
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) adopted a conservation measure for establishing a network of marine protected areas (MPAs) in 2011. Since then, a number of proposals have been submitted to the Commission, but their designation has been consistently opposed by some pro-fishing CCAMLR member countries. This article provides an analysis of CCAMLR institutional and decision-making processes in an attempt to explain the obstacles preventing the creation of a network of MPAs. The role of environmental nongovernmental organizations (ENGOs) is examined through their track record in Antarctic environmental governance as well as the extent of their participation within the CCAMLR MPA process. 相似文献
4.
No study has been done on the impact of anthropogenic risks on protected areas. This may be due to complexity and diversity of risk assessment indices. In this research, using multicriteria decision-making methods, qualitative and complex indices were converted to simple and quantitative indices by which anthropogenic risks affecting the Helleh Protected Area in Iran were analyzed. To this end, a questionnaire was prepared and delivered to Delphi panelists consisting of environmental expertise. In order to prioritize the identified risks, Technique for Order Preference by Similarity to Ideal Solution (TOPSIS), Analytical Hierarchy Process (AHP), and Simple Additive Weighting Technique (SAW) were used as a subset of Multiple Attribute Decision-making methods (MADM). In this study, risk factors were evaluated using three criteria of severity, probability of occurrence, and sensitivity of the recipient environment. In order to reach enough transcendence (consensus on priority of risks), an integrated approach comprising average, Borda, and Copeland methods was used. The obtained results suggested that “dam inundation upstream of the study area” is a top-priority risky factor threatening the wetland. “Stopping water pumps from the wetland” and “use of modern irrigation systems” were recommended as the most effective managerial strategies to control the identified risk. 相似文献
5.
Ostracod faunas at six locations are compared, and related to distributions in an Atlantic Ocean-wide data base. Five, widely developed, vertical faunal sequences are recognised at particular levels within deep water-masses: Henryhowella Fauna (lower part of Antarctic Intermediate Water); Krithe Fauna (Upper North Atlantic Deep Water); Poseidonamicus-Bosquetina Fauna (upper part of Lower NADW); Dutoitella Fauna (lower part of Lower NADW); Legitimocythere Fauna (Antarctic Bottom Water). These faunas are correlated with previously established deep water benthic foraminiferal assemblages, and their possible palaeo-oceanographic use is discussed. 相似文献
6.
The Atlantic Forest (AF) of Brazil is a highly endangered natural ecosystem whose rural human inhabitant’s socioeconomic and
health situation also is generally precarious. Using a transdisciplinary and participatory methodology, the different characteristics
of rural populations living near three protected areas in Santa Teresa—ES, Brazil, were investigated in a pilot project examining
the human groups and the biodiversity of the region. This article presents a general overview of the project, its bioanthropological
methodology, socioeconomic, demographic, environmental perception, and sanitary findings, and their possible implications
for the three protected areas. A total of 178 families, living in 119 properties participated in the research. The water and
sanitation infrastructure of these properties is often poor, over 85% of the cultivated land is used for products which make
heavy use of pesticides and chemical fertilizers, education levels are low, and two-thirds of the inhabitants do not perceive
a value in the protected areas. Hunting and extraction of forest products in the areas is common and many local animal species
are highly endangered. Considering that the AF protected areas are under intense anthropogenic pressure, it is imperative
to study their surrounding populations in order to propose initiatives that can contribute simultaneously to environmental
conservation and the improvement of their quality of life. The project is based on the participation of the local population
with the aim of contributing to a better integration of the communities with the protected areas. 相似文献
7.
Enrico Di Minin Luke T. B. Hunter Guy A. Balme Robert J. Smith Peter S. Goodman Rob Slotow 《PloS one》2013,8(8)
The ideal conservation planning approach would enable decision-makers to use population viability analysis to assess the effects of management strategies and threats on all species at the landscape level. However, the lack of high-quality data derived from long-term studies, and uncertainty in model parameters and/or structure, often limit the use of population models to only a few species of conservation concern. We used spatially explicit metapopulation models in conjunction with multi-criteria decision analysis to assess how species-specific threats and management interventions would affect the persistence of African wild dog, black rhino, cheetah, elephant, leopard and lion, under six reserve scenarios, thereby providing the basis for deciding on a best course of conservation action in the South African province of KwaZulu-Natal, which forms the central component of the Maputaland-Pondoland-Albany biodiversity hotspot. Overall, the results suggest that current strategies of managing populations within individual, small, fenced reserves are unlikely to enhance metapopulation persistence should catastrophic events affect populations in the future. Creating larger and better-connected protected areas would ensure that threats can be better mitigated in the future for both African wild dog and leopard, which can disperse naturally, and black rhino, cheetah, elephant, and lion, which are constrained by electric fences but can be managed using translocation. The importance of both size and connectivity should inform endangered megafauna conservation and management, especially in the context of restoration efforts in increasingly human-dominated landscapes. 相似文献
8.
Philobryids (Bivalvia: Arcoida) are one of the most speciose marine bivalve families in the Southern Ocean and are common throughout the Southern Hemisphere. Considering this diversity and their brooding reproductive mode (limiting long-distance dispersal), this family may have been present in the Southern Ocean since its inception. However Philobrya and Adacnarca appear only in the Quaternary fossil record of the Antarctic, suggesting a much more recent incursion. Molecular dating provides an independent means of measuring the time of origin and radiation of this poorly known group. Here we present the first combined molecular and morphological investigation of the Philobryidae in the Southern Ocean. Two nuclear loci (18S and 28S) were amplified from 35 Southern Ocean Adacnarca and Philobrya specimens, with a combined sequence length of 2,282 base pairs (bp). Adacnarca specimens (A. nitens and A. limopsoides) were resolved as a strongly supported monophyletic group. Genus Philobrya fell into two strongly supported groups (‘sublaevis’ and ‘magellanica/wandelensis’), paraphyletic with Adacnarca. The A. nitens species complex is identified as at least seven morpho-species through morphological and genetic analysis of taxon clustering. Phylogenetic analyses resolve Philobryidae as a strongly supported monophyletic clade and sister taxon to the Limopsidae, as anticipated by their classification into the superfamily Limopsoidea. Bayesian relaxed clock analyses of divergence times suggest that genus Adacnarca radiated in the Southern Ocean from the Early Paleogene, while P. sublaevis and P. wandelensis clades radiated in the late Miocene, following the formation of the Antarctic Circumpolar Current. 相似文献
9.
C. San Vicente J. Castelló J. Corbera A. Jimeno T. Munilla M. C. Sanz J. C. Sorbe A. Ramos 《Polar Biology》2007,30(4):477-486
During the austral summer 1995, suprabenthic samplings were carried out at 24 stations (depth range 45–649 m) located around
Livingston Island, within the caldera of Deception Island and in the Bransfield Strait. At each station, the near-bottom motile
fauna was simultaneously collected with a multinet Macer-GIROQ sled in three water layers above the bottom. This study presents
original data on the occurrence, diversity, vertical distribution and abundance of suprabenthic taxa in this near-bottom environment.
The most speciose taxa were amphipods (at least 140 spp.), followed by isopods (66 spp.), pycnogonids (31 spp.) and mysids
(19 spp.). Total abundances ranged between 31 ind./100 m2 (Bransfield Strait, 361 m depth) and 6817 ind./100 m2 (South Livingston Island, 163 m depth). According to stations, the groups numerically dominant and more frequent were amphipods
(17 stations) or mysids (seven stations). Four suprabenthic assemblages were discriminated in the study area, apparently more
structured by the degree of shelter-exposure and development of sessile epifauna than by water depth or sediment features. 相似文献
10.
Paolo Guidetti Pasquale Baiata Enric Ballesteros Antonio Di Franco Bernat Hereu Enrique Macpherson Fiorenza Micheli Antonio Pais Pieraugusto Panzalis Andrew A. Rosenberg Mikel Zabala Enric Sala 《PloS one》2014,9(4)
Marine protected areas (MPAs) were acknowledged globally as effective tools to mitigate the threats to oceans caused by fishing. Several studies assessed the effectiveness of individual MPAs in protecting fish assemblages, but regional assessments of multiple MPAs are scarce. Moreover, empirical evidence on the role of MPAs in contrasting the propagation of non-indigenous-species (NIS) and thermophilic species (ThS) is missing. We simultaneously investigated here the role of MPAs in reversing the effects of overfishing and in limiting the spread of NIS and ThS. The Mediterranean Sea was selected as study area as it is a region where 1) MPAs are numerous, 2) fishing has affected species and ecosystems, and 3) the arrival of NIS and the northward expansion of ThS took place. Fish surveys were done in well-enforced no-take MPAs (HP), partially-protected MPAs (IP) and fished areas (F) at 30 locations across the Mediterranean. Significantly higher fish biomass was found in HP compared to IP MPAs and F. Along a recovery trajectory from F to HP MPAs, IP were similar to F, showing that just well enforced MPAs triggers an effective recovery. Within HP MPAs, trophic structure of fish assemblages resembled a top-heavy biomass pyramid. Although the functional structure of fish assemblages was consistent among HP MPAs, species driving the recovery in HP MPAs differed among locations: this suggests that the recovery trajectories in HP MPAs are likely to be functionally similar (i.e., represented by predictable changes in trophic groups, especially fish predators), but the specific composition of the resulting assemblages may depend on local conditions. Our study did not show any effect of MPAs on NIS and ThS. These results may help provide more robust expectations, at proper regional scale, about the effects of new MPAs that may be established in the Mediterranean Sea and other ecoregions worldwide. 相似文献
11.
Most assessments of present protected areas have focused on which features are or are not represented and to what extent, but they have not considered the environmental gradients and the geographic context within each biodiversity feature under a conservation network. We examined how protected areas are distributed with respect to the distribution of six forest community types. Three analyses were applied to the dataset in the Red Data Book of Plant Communities in Japan and the related survey: (1) recursive partitioning was used to contrast environmental factors of conserved communities with nonconserved communities; (2) point pattern analysis, based on Ripley's K function, was used to describe the spatial pattern of conserved communities; and (3) the spatial scan statistic was used to detect spatial representation gaps. Overall, environmental bias was greatest in relation to soil and topography. However, the results of point pattern analysis showed that the spatial pattern of conserved communities did not depend entirely on the distribution of environmental factors. Four types of gaps in spatial representation were detected by the spatial scan statistic, irrespective of environmental bias. These results showed that although a community type might be well protected in total or along the environmental gradients, conserved communities might not capture the full range of geographic context. To ensure appropriate representation or protection, it is important that conservation planning for protected areas take into account both the environmental gradients and the geographic context within each biodiversity feature. 相似文献
12.
Fishes of the Southern Ocean 总被引:2,自引:0,他引:2
Graeme Parkes 《Reviews in Fish Biology and Fisheries》1992,2(4):344-345
13.
14.
With the aims of investigating the response of the smallest benthic biota to a strong ice-edge-related input of phytodetritus, and of registering supposed lateral transportation processes of phytodetrital matter with northerly direction under the ice, we analysed a number of abiotic and biotic parameters in surface sediments from the northern Fram Strait. Two transects of 14 stations in total were made. One transect, crossing the Fram Strait from the east to the west, followed mainly the ice edge. The second transect extended latitudinally in a northerly direction, starting in ice-free areas, passing the ice edge, and ending in heavy ice-covered areas, approximately 100 nm north of the ice edge. Stations along this transect were sampled at almost constant water depths to avoid depth-related influences in our investigations. Results showed the expected high phytodetritus concentrations in the ice-edge vicinity. Concentrations of sediment-bound plant pigments were approximately 5 times higher than in ice-covered areas, indicating a very strong phytodetritus input. With increasing distance from the highly productive areas at the ice edge, we found significantly decreasing concentrations of phytodetrital input to the seafloor in a northerly direction. Within the foraminiferans, generic diversity was clearly reduced in the area of strong phytodetritus deposition. Along the latitudinal transect, out of the direct ice-edge influence, foraminiferal diversities slowly increased within increasing distance from the ice edge. The integration of results from earlier foraminiferal investigations, from stations further to the north, indicates a once more decreasing diversity with continually decreasing food supply. 相似文献
15.
Ana Maria Rodrigues Sónia Meireles Teresa Pereira Alice Gama Victor Quintino 《Hydrobiologia》2006,555(1):99-113
This study characterizes the composition and spatial distribution patterns of the benthic macrofauna in the intertidal mudflats
of the Tagus estuary, western Portugal. A total of 68 species, more than 226,000 specimens with a total wet weight biomass
of approximately 1170 g were identified in 380 sites. The species Streblospio shrubsolii, Cyathura carinata, Tharyx sp., Hydrobia ulvae and Tubificids were the most common and abundant. Scrobicularia plana strongly dominated the biomass. The invertebrate macrofauna of the Tagus estuary shows similarities to what is known from
other temperate mudflats. The diversity of species, their overall abundance and the ratio of Molluscs plus Crustaceans to
Polychaete species corroborate the distinctiveness between temperate and tropical mudflats and sandflats. The spatial distribution
of the fauna reflects the sediment characteristics but the relationship between the environmental and the biological data
is not as strong as obtained for sublittoral areas. This relationship diminishes from the sublittoral shelf to sublittoral
estuarine areas, showing minimum values in this study, suggesting that such a relationship is less straightforward as natural
disturbance increases. Nevertheless, a mixture of grain-size, elevation (inundation time) and particular habitats (relic oyster
beds) form the best explanatory factors for the spatial distribution patterns of the intertidal benthic macrofauna of the
Tagus estuary. 相似文献
16.
In this study isopod species of the Ross Sea were investigated. Literature until May 2008 was checked to provide an overview of all known and described species in the Ross Sea. This species checklist was then enlarged through material of the 19th Italica expedition in 2004. During this expedition for the first time a small mesh net (500 μm) was used. Nine thousand four hundred and eighty one isopod specimens were collected during this expedition. Through this material the number of isopod species in the Ross Sea increased from 42 to 117 species, which belong to 20 families and 49 genera. Fifty-six percentage of the isopods species collected during the Italica expedition are new to science. The zoogeography of the 117 species was investigated. A non-transformed binary presence-absence data matrix was constructed using the Bray–Curtis coefficient. The results were displayed in a cluster analysis and by nonmetric multidimensional scaling (MDS). This paper gives a first insight into the occurrence and distribution of the isopod species of the Ross Sea. 相似文献
17.
Camille Lebarbenchon Robert Poulin Michel Gauthier-Clerc Frédéric Thomas 《EcoHealth》2006,3(4):303-307
For the past several years, there has been growing interest in understanding the dynamics of parasites in ecosystems, as well
as the diversity of ways in which they interfere with conservation and health preoccupations. Although it is widely recognized
that many conservation practices (e.g., wildlife translocations, species removal, food supplementation) may be associated
with parasite-related problems, less attention has been devoted to exploring the parasitological consequences of the overcrowding
of animals in protected wildlife areas. Here, we discuss this important ecological/epidemiological problem, presenting at
the same time an overview of the main questions and challenges in this field. Using empirical and theoretical examples chosen
from the literature, we focus particularly on the interactions between the overcrowding of free living species and parasite
population dynamics, the evolution of parasite virulence, the indirect effects on the structure of invertebrate communities,
as well as the nutritional value of prey species. We argue that conservation policies should be aware more than ever of this
problem, especially given the serious health risks currently posed by the spread of virulent viruses (e.g., avian influenza). 相似文献
18.
Protected areas (PAs) have been established to conserve tropical forests, but their effectiveness at reducing deforestation is uncertain. To explore this issue, we combined high resolution data of global forest loss over the period 2000–2012 with data on PAs. For each PA we quantified forest loss within the PA, in buffer zones 1, 5, 10 and 15 km outside the PA boundary as well as a 1 km buffer within the PA boundary. We analysed 3376 tropical and subtropical moist forest PAs in 56 countries over 4 continents. We found that 73% of PAs experienced substantial deforestation pressure, with >0.1% a−1 forest loss in the outer 1 km buffer. Forest loss within PAs was greatest in Asia (0.25% a−1) compared to Africa (0.1% a−1), the Neotropics (0.1% a−1) and Australasia (Australia and Papua New Guinea; 0.03% a−1). We defined performance (P) of a PA as the ratio of forest loss in the inner 1 km buffer compared to the loss that would have occurred in the absence of the PA, calculated as the loss in the outer 1 km buffer corrected for any difference in deforestation pressure between the two buffers. To remove the potential bias due to terrain, we analysed a subset of PAs (n = 1804) where slope and elevation in inner and outer 1 km buffers were similar (within 1° and 100 m, respectively). We found 41% of PAs in this subset reduced forest loss in the inner buffer by at least 25% compared to the expected inner buffer forest loss (P<0.75). Median performance () of subset reserves was 0.87, meaning a reduction in forest loss within the PA of 13%. We found PAs were most effective in Australasia (), moderately successful in the Neotropics () and Africa (), but ineffective in Asia (). We found many countries have PAs that give little or no protection to forest loss, particularly in parts of Asia, west Africa and central America. Across the tropics, the median effectiveness of PAs at the national level improved with gross domestic product per capita. Whilst tropical and subtropical moist forest PAs do reduce forest loss, widely varying performance suggests substantial opportunities for improved protection, particularly in Asia. 相似文献
19.
We report the first record of a northern rockhopper penguin Eudyptes moseleyi on the Kerguelen Islands, Southern Indian Ocean. The penguin must have crossed the subtropical convergence to reach the island. This species was recently proved to be genetically different from the subantarctic eastern rockhopper penguin E. filholi that normally breeds on the Kerguelen Islands. The sequencing of a part of the mitochondrial control region shows that this bird may come from the population of Gough Island, 6,000 km away, in the south Atlantic Ocean. This finding confirms that the genetic isolation between these two penguin species is complete, although some individuals may sporadically disperse between the breeding sites. This first direct observation of a disperser from the Atlantic to the Indian Ocean also adds further support to a biogeographic dispersion pattern already suggested by phylogeographic patterns in other species from the Southern Ocean. 相似文献
20.
Soon after longlining on Patagonian toothfish (Dissostichus eleginoides) started in the Southern Ocean in the second half of the 1980s, interactions of cetaceans with these fisheries became apparent.
The two species primarily involved were orcas (killer whales) (Orcinus orca) and male sperm whales (Physeter macrocephalus). Both species took substantial number of fish from the line primarily during day light hours. Catch rates of longliners
declined to less than 50% when orcas occurred close to longline vessels while the loss to sperm whales was much less obvious.
They were seen diving close to the line down to 400 m where they apparently took fish. Their impact on catch rates was much
less notable. Sperm whales became frequently entangled in the line and part of the line was lost in a number of cases. Other
cetaceans were rarely seen in the vicinity of longline vessels. They became entangled in the line only occasionally and one
whale (presumably a minke whale) died. 相似文献