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1.
Within the marine conservation community there is considerable interest in combining local knowledge and science to achieve management objectives. Yet there remain few studies which have examined the merits and caveats of local knowledge, or shown how combining both knowledge systems has resulted in better management outcomes. This study outlines collaborative efforts to conserve fish spawning aggregations (FSAs) in Roviana Lagoon, Western Solomon Islands. Baseline information on FSAs was obtained through local knowledge and spearfishing creel surveys. This information provided the starting point for establishing a 2-year community-based underwater monitoring program at the largest known FSA in Roviana Lagoon, where the brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) co-aggregate. This participatory research shows that local knowledge on FSAs is utilised to maximise returns from fishing, with spearfishermen targeting aggregations at night during the lunar periods when abundances peak. Because of its shallow distribution P. areolatus is the most vulnerable of the three groupers to nighttime spearfishing, with two fishermen capable of removing 15–30% of the total spawning biomass in two nights. Underwater monitoring demonstrates that while fishermen provided accurate information on many aspects of FSAs, their knowledge on spawning seasons was inaccurate for the FSA reported on here. Peak aggregations occurred from December to April each year, which differs from the traditionally recognised grouper season of October to January. A combination of local knowledge and science was used to develop appropriate management measures for this FSA, with the aggregation declared a community-based marine protected area (MPA) in 2006.  相似文献   

2.
Increasing the level of protection afforded to the marine environment requires assessment of the efficacy of existing marine protected areas (MPAs) in protecting exploited species. Long-term data from before and after the establishment of MPAs provide a rare but valuable opportunity to assess these effects. In this study we present long-term data (1977-2005) from before and after park establishment, on the abundance of spiny lobster Jasus edwardsii from fixed sites in a no-take marine park and a recreationally fished marine park, to assess the efficacy of no-take vs. partial protection. Lobster densities were comparable between both marine parks prior to park establishment, but the response of lobster populations differed markedly following protection. On average, legal-sized lobster were eleven times more abundant and biomass 25 times higher in the no-take marine park following park establishment, while in the partially protected marine park there has been no significant change in lobster numbers. Furthermore, no difference was found in densities of legal-sized lobster between the partially protected marine park and nearby fully-fished sites (<1 per 500 m2). Long-term data from fully fished and partially protected sites suggest long-term declines in lobster populations and reflect regional patterns in catch per unit effort estimates for the fishery. The long-term patterns presented provide an unequivocal example of the recovery of lobster populations in no-take MPAs, but clearly demonstrate that allowing recreational fishing in MPAs has little benefit to populations of exploited species such as J. edwardsii.  相似文献   

3.
Populations of a protandric limpet, Cymbula oculus, were compared between two South African Marine Protected Areas (MPAs), Dwesa and Tsitsikamma, and four exploited sites, and between sites exposed to or sheltered from strong wave action. Harvesting is decimating populations of this limpet. Compared with harvested sites, limpets in MPAs were 30-50% larger, adult densities 75% greater and biomass 30-90% greater. The female:male ratio was 0.58:1 inside the MPAs, but 0.11:1 at harvested sites. Growth rate and age-at-maturity were unaffected by harvesting, but survivorship was 10-fold higher inside MPAs, and reproductive output a staggering 80-fold higher. Conversely, recruitment was three times higher in harvested than protected areas, and inversely correlated with adult density. Wave action had negative effects of similar magnitude to harvesting. Limpets at sheltered sites were 65% larger, biomass 80% greater, female proportions 40% higher, survivorship 25% greater and growth 33% greater. Recruitment was, however, 45% greater at wave-exposed sites. All these effects were detected only inside the MPAs, being masked by harvesting elsewhere. The impacts of harvesting and wave action could never have been detected without the existence of MPAs, emphasizing their importance for base-line studies as well as protection. Dwesa MPA is under threat from poaching and demands for access to resources, but a strong case exists for retaining at least a core fully protected area. Our results clearly illustrate the need for MPAs among the tools used for coastal management.  相似文献   

4.
We assessed home range size for breeding loggerhead turtles (Caretta caretta) near the limit of the species range at the Greek island of Zakynthos in the Mediterranean. Thirteen adult females and seven adult males were tracked using GPS units (loggers and transmitters) during May and June of 2006, 2007 and 2008. Kernel analysis indicated that core home range sizes (50% estimator; range: 2.9-19.7 km2) for both males and females were restricted to a 7.5 km tract of coastline. 15% of GPS locations fell outside of the national park protection zones, while within the protected breeding area 88% of GPS locations occurred in zones of minimal protection. Female home ranges were 64% larger in 2008 than in 2006 and 2007, indicating that several years monitoring may be required for the most effective designation of marine protected areas (MPAs). Ten of the tracked females departed the core breeding area on 15 occasions for periods of 1-15 days travelling distances of 10-100 km, although none nested at alternative breeding sites. The inter-annual variability of breeding area home range size and likelihood of incidence of forays appeared be correlated with barometric pressure. The movement responses of loggerheads to environmental conditions implicates an ability to switch nesting areas over small scales in response to climate change. However, such behaviour suggests the protection of existing core breeding sites may be inadequate, with policy makers being required to consider the protection of broader areas to encompass potential changes in the habitat needs of this species.  相似文献   

5.
The effects of cattle manure and inorganic N‐fertilizer application on soil organic carbon (SOC), bulk density, macro‐aggregate stability and aggregate protected carbon were determined on clay and sandy soils of the Murewa smallholder farming area, Zimbabwe. Maize was grown in four fields termed homefields (HFs) and outfields (OFs) because of spatial variability induced by management practices and with the following fertility treatments: control (no fertility amelioration), 5, 15 and 25 t/ha cattle manure + 100 kg/ha N applied annually for seven consecutive years. The addition of cattle manure resulted in significant (P < 0.01) increases in SOC, macro‐aggregate stability and aggregate protected carbon in clay soils from at least the 5 t/ha cattle manure rate and was comparable between HFs and OFs on clay soils. Aggregate protected carbon in clay soils was significantly higher from the 15 and 25 t/ha cattle manure rates compared to the 5 t/ha cattle manure treatment. In contrast, only SOC was significantly (P < 0.05) increased with the addition of cattle manure on the sandy soils, while bulk density, macro‐aggregate stability and aggregate protected carbon were not significantly changed. Bulk density was also not significantly (P > 0.05) different on the clay soils. A significant and positive linear relationship (r2 = 0.85) was found between SOC and macro‐aggregate stability, while an r2 value of 0.82 was obtained between SOC and aggregate protected carbon on the clay soils. However, no regressions were performed on data from the sandy soils because of the lack of significant changes in soil physical properties. Application of cattle manure and inorganic N‐fertilizer significantly increased (P < 0.05) maize grain yield on both soil types. Results show that inorganic N‐fertilizer combined with cattle manure at 5–15 t/ha per yr is necessary to increase maize yields and SOC on sandy soils in Murewa, while at least 15 t/ha per yr cattle manure is required on the clay soils to improve physical properties in addition to maize yields and SOC.  相似文献   

6.
Extent and conservation of tropical dry forests in the Americas   总被引:1,自引:0,他引:1  
This paper shows the results of an assessment on the current extent of Neotropical dry forests based on a supervised classification of MODIS surface reflectance imagery at 500-m resolution. Our findings show that tropical dry forests extend for 519,597 km2 across North and South America. Mexico, Brazil and Bolivia harbor the largest and best-preserved dry forest fragments. Mexico contains the largest extent at 181,461 km2 (38% of the total), although it remains poorly represented under protected areas. On the other hand, Brazil and Bolivia contain the largest proportion of protected tropical dry forests and the largest extent in continuous forest fragments. We found that five single ecoregions account for more than half of the tropical dry forests in the Americas (continental and insular) and these ecoregions are: the Chiquitano dry forests, located in Bolivia and Brazil (27.5%), the Atlantic dry forests (10.2%), the Sinaloan dry forests in Mexico (9.7%), the Cuban dry forests (7.1%) and the Bajio dry forests in Mexico (7%). Chiquitano dry forests alone contain 142,941 km2 of dry forests. Of the approximately 23,000 km2 of dry forest under legal protection, 15,000 km2 are located in just two countries, Bolivia and Brazil. In fact, Bolivia protects 10,609 km2 of dry forests, where 7600 km2 are located within the Chiquitano dry forest ecoregion and protected by a single park. Low extent and high fragmentation of dry forests in countries like Guatemala, Nicaragua, Ecuador, Costa Rica and Peru means that these forests are at a higher risk from human disturbance and deforestation.  相似文献   

7.
The endemic Seram cockatoo, Cacatua moluccensis, was placed on Appendix I of CITES in response to declining trade statistics but in the absence of population data. We conducted population surveys and collected data on habitat structure at seven sites on Seram in 1998. Cockatoo densities ranged from 0.93 to 17.25 birds/km2 and averaged 7.9 birds/km2 across sites. We classified habitat into three types but found that cockatoo densities did not correspond closely to habitat differences across sites. Cockatoo abundance was significantly associated with presence of potential nest trees and strangling figs. Analysis of forest cover and landuse indicates that while most of the island is still covered in lowland forest, only 14% of these forests are protected and almost half the island is classified as logging concession. Conservation recommendations include better information and enforcement of laws protecting Seram cockatoos and resolution of boundary conflicts between parks and logging concessions.  相似文献   

8.
Recognizing the importance of preserving biodiversity and ecosystem services, human society has established extensive protected area networks to conserve these resources in recent decades. Are protected areas working as expected? Empirical coarse-scale assessments of this question across large regions, or even globally, tend to answer “yes”, while fine-scale studies of individual protected areas often and repeatedly answer “no”. We conducted a first fine-scale analysis of Brazil’s extensive Amazonian protected area network (1.8 million km2) and have quantitatively estimated conservation effectiveness in light of changing human development pressures in the surrounding landscape. The overall network maintained intact forest cover for 98.6% of protected forest lands, largely agreeing with previous coarse-scale studies. However, detailed examination of 474 individual protected areas unveils a broad range of efficacy. Many protected areas (544,800 km2) experience default protection simply due to their remoteness. Many others (396,100 km2) have provided highly effective protection in the face of substantial human development pressure. Conversely, 12% (38) of protected areas have failed to protect the 27,300 km2 that they encompass, and another 7% (23) provide only marginal protection of 37,500 km2. Comprehensive landscape assessments of protected area networks, with frequent monitoring at scales matching the patterns of human-caused disturbances, are necessary to ensure the conservation effectiveness and long term survival of protected areas in rapidly changing landscapes. The methods presented here are globally adaptable to all forested protected areas.  相似文献   

9.
A.J. Fristensky  M.E. Grismer   《CATENA》2009,79(1):93-102
Application of organic soil amendments to disturbed soil has been shown to improve aggregate stability and reduce soil susceptibility to erosion. Employing ultrasonic aggregate stability assessment techniques described earlier [Fristensky, A. and Grismer, M.E., 2008. A simultaneous model for ultrasonic aggregate stability assessment. Catena, 74: 153–164.], we assess the effect of two experimental organic soil amendments – a compost and a woodchip mulch incorporated at a rate of 2000–6000 kg ha− 1 N-equivalence – on soil aggregation and aggregate stability at four drastically disturbed sites within the Lake Tahoe Basin, USA. Experimental plots were established 1–3 years prior to testing. The soils were of granitic or volcanic origin, and disturbed by either ski run or road development. Soil treatments were observed to significantly (p < 0.05) increase both aggregation (300% average increase) and ultrasonic aggregate stability (600% average increase) relative to the untreated soil. However, at the two sites disturbed by ski run development, the control treatment (tilling and surface application of pine–needle mulch) performed comparably to the two incorporated compost treatments, suggesting that the effects of the experimental amendments on aggregation were negligible at these sites, or their effective duration was shorter than the evaluation period.Rainfall simulations (72–120 mm h− 1) were performed on the treatment plots, and results were compared with the ultrasonic aggregate stability indices. Significant (p < 0.05) positive correlations were obtained between the measurements of aggregate instability and indices of soil susceptibility to runoff, including steady-state infiltration rate (measured values between 1 and 120 mm h− 1), and the level of kinetic energy of applied rainfall at which runoff commences (EBR, measured values between 12 and 224 J m− 2). However, no correlation was found between the ultrasonic aggregate stability indices and observed soil erosion variables. Interestingly, positive relationships (p < 0.05) were observed between both infiltration rate and EBR and the proportion of 2–20 μm and < 2 μm particles liberated from the largest aggregates detected in each soil. Our results suggest that ultrasonic aggregate stability indices may be useful indicators of soil susceptibility to runoff and erosion under rainfall.  相似文献   

10.
Earthworms are known to play a role in aggregate formation and soil organic matter (SOM) protection. However, it is still unclear at what scale and how quickly earthworms manage to protect SOM. We investigated the effects of Aporrectodea caliginosa on aggregation and aggregate-associated C pools using 13C-labeled sorghum (Sorghum bicolor (L.) Moench) leaf residue. Two incubations were set up. The first incubation consisted of soil samples crushed <250 μm to break up all macroaggregates with three treatments: (i) control soil; (ii) soil+13C-labeled residue and (iii) soil+13C-labeled residue+earthworms. Earthworms were added after 8 d and 12 d (days) later, aggregate size distribution was measured together with total C and 13C in each aggregate fraction. A second incubation was made to assay protected versus unprotected total C and 13C from 21-d laboratory incubations of intact and crushed large (>2000 μm) and small (250-2000 μm) macroaggregates and microaggregates (53-250 μm). Eight different pools of aggregate-associated C were quantified: (1) and (2) unprotected C pools in large and small macroaggregates, (3) unprotected C pools in microaggregates, (4) and (5) protected C pools in large and small macroaggregates, (6) protected C pool in microaggregates, and (7) and (8) protected C pools in microaggregates within large and small macroaggregates. In the presence of earthworms, a higher proportion of large macroaggregates was newly formed and these aggregates contained more C and 13C compared to bulk soil. There were no significant differences between the samples with or without earthworms in the C pool-sizes protected by macroaggregates, microaggregates or microaggregates within small macroaggregates. However, in the presence of earthworms, the C protected by microaggregates within large macroaggregates was a significant pool and 22% of this C pool was newly added C. In conclusion, these results clearly indicate the direct involvement of earthworms in providing protection of soil C in microaggregates within large macroaggregates leading to a possible long-term stabilization of soil C.  相似文献   

11.
Global declines in shark populations have created uncertainty in the future status of many species and conservation efforts are urgently needed. Marine protected areas (MPAs) are used increasingly as conservation tools around the world, but how they benefit mobile and wide ranging species like sharks remains unclear. To evaluate the degree of protection MPAs may provide for sharks, we used an array of acoustic receivers to examine the movements and spatial use of two tropical coastal species within two MPAs in the Great Barrier Reef Marine Park, Australia. Juvenile pigeye (Carcharhinus amboinensis) and adult spottail (Carcharhinus sorrah) sharks were fitted with acoustic transmitters from 2009 to 2010. Both species displayed long-term use of MPAs, with some individuals detected for longer than 600 days. The mean percentage of time C. amboinensis and C. sorrah spent inside MPAs was 22% and 32%, respectively. MPA use varied seasonally, with C. amboinensis spending a higher percentage of time inside MPAs in summer (mean = 28%) and C. sorrah spending a higher percentage of time inside MPAs in winter (mean = 40%). Although sharks used large areas inside MPAs, most individuals tended to use only half of the available protected space. In addition, all sharks made excursions from MPAs and individuals exited and re-entered at consistent locations along the MPA boundaries. These results demonstrate that MPAs have conservation benefits for shark populations by providing protection across different species and life stages, and tracking studies can be used to help tailor MPA design to maximize effectiveness.  相似文献   

12.
In addition to protecting important species or ecosystems, ideally Marine Protected Areas (MPAs) should also act as propagule sources and be located where they can receive larval influxes so as to buffer species against local extinctions and allow genetic mixing. There are many examples of island MPAs across the world because of their advantages compared to mainland sites, and although evidence suggests they effectively protect biodiversity and may have localized fisheries benefits, their contribution to larval export and connectivity to mainland areas remains largely unknown; these are important aspects of MPA sustainability and functioning. Here I examined the genetic differentiation between four island MPAs in northern Europe and their respective mainlands, relative to differentiation of populations along the coast at similar spatial scales for two marine invertebrates (Semibalanus balanoides, planktonic larvae; Nucella lapillus, direct development). These data were used to infer past patterns of larval exchange between populations. Gene flow was restricted at all four locations between the islands and the mainland, compared to gene flow along the coast (for both species) and more distant islands had greater differentiation than those closer to the mainland for S. balanoides, but not for N. lapillus. My results of genetic analysis suggest that island MPAs may not provide as much larval export or receive as much buffering against local extinctions, compared with mainland populations (for a similar sized protected area). My findings are especially relevant to the creation of MPA networks and in understanding the importance of connectivity in achieving the greatest fisheries benefits and in ensuring inter-MPA linkages. Low levels of larval exchange may limit the success of any protected area and may prevent multiple conservation objectives from being achieved.  相似文献   

13.
As part of our ungulate population protection program, the specific causes of ungulate mortality were examined and the effect of single habitat on habitat selection by ungulate analyzed. An integrated occurrence–mortality model for three ungulate species (wild boar Sus scrofa L., red deer Cervus elaphus L. and roe deer Capreolus capreolus Pallas) within the Wanda Mountains of Heilongjiang Province, China was then created. Results showed that steel cable snares and poison, used to kill ungulates, were the primary threats to survival of wild boar (40.07% poison, 27.79% cable snares), red deer (51.35% poison, 40.54% cable snares) and roe deer (29.31% poison, 56.90% cable snares). Furthermore, we found evidence that aspect, slope, elevation and forest type are important factors in determining ungulate habitat preference. The integrated occurrence–mortality model indicated that 46.39% of suitable habitat was associated with mortality risk. This model correctly classified 8.06% (297.49 km2) of the study area as unsuitable habitat, 5.43% (200.44 km2) as first attractive sink-like habitat, 32.76% (1209.85 km2) as second attractive sink-like habitat, 8.20% (302.77 km2) as third attractive sink-like habitat, and 8.91% (329.00 km2), 30.53% (1127.22 km2) and 6.11% (225.29 km2) as first, second and third source-like habitats, respectively. The results indicate that source-like habitats should be preserved to prevent habitat loss and degradation, while attractive sink-like habitats should be managed effectively to mitigate mortality risks. In particular, the various authorities need to be more proactive (increase patrolling, thereby providing employment, educational opportunities and increasing income) to reduce human-caused ungulate mortality.  相似文献   

14.
The influence of landscapes and vegetation types on soil aggregate stability was studied at 55 sites in rangeland and 18 sites in cropland in northeastern Syria. For the measurement of soil aggregate stability, the wet-sieving test was applied to air-dried and prewetted aggregates. As soil properties, pH, EC, organic carbon content, inorganic carbon content, sand content were determined. Slope gradients at all the sites and soil surface coverage at the sites in the rangeland were also determined. Due to the slaking process, the stability of air-dried aggregates with a mean value of 47.5 × 10-2 kg kg-1 was lower than that of prewetted ones with a mean value of 89.8 × 10-2 kg kg-1. The absence of a significant relationship between the soil aggregate stability and soil chemical properties in the cropland suggested the influence of tillage. Principal component analysis and stepwise multiple regression analysis for the sites in the rangeland indicated that the air-dried aggregate stability could be described by a coverage factor and slope factor (r=0.76). The contribution of the coverage factor suggested that the increase of the soil organic matter content through the addition of plant materials and protection of the soil surface from the raindrop impact could enhance the soil aggregate stability. The positive contribution of the slope factor implied that unstable aggregates on steeper slopes had already been translocated, while stable aggregates remained. Thus, for the preservation of the soil aggregate stability, the soil surface coverage should be improved especially on gentler slopes.  相似文献   

15.
Systematic approaches to site selection for marine protected areas (MPAs) are often favored over opportunistic approaches as a means to meet conservation objectives efficiently. In this study, we compared analytically the conservation value of these two approaches. We locate this study in Danajon Bank, central Philippines, where many MPAs were established opportunistically based on community preference, with few if any contributions from biophysical data. We began by identifying the biophysical data that would have been available when the first MPA was created in Danajon Bank (1995). We next used these data with the reserve selection software Marxan to identify MPAs that covered the same area as is protected under the current set of MPAs (0.32% of the total study area) and that would protect the greatest number of conservation targets at the lowest cost. We finally compared the conservation value of the current MPAs to the value of those selected by Marxan. Because of the dearth of biophysical data available in 1995 and the small area currently under protection, Marxan identified multiple configurations of MPAs that would protect the same percentage of conservation targets, with little differentiation among sites. Further, we discovered that the costs of obtaining and analyzing these data to be used for conservation planning would have been large relative to resources typically available to conservation planners in developing countries. Finally, we found that the current set of MPAs protected more ecological features than would be expected by chance, although not as many as could be protected using a systematic approach. Our results suggest that an opportunistic approach can be a valuable component of conservation planning, especially when biophysical data are sparse and community acceptance is a critical factor affecting the success of an MPA.  相似文献   

16.
Connectivity of the Asiatic wild ass population in the Mongolian Gobi   总被引:1,自引:0,他引:1  
Long-distance migrations of wildlife have been identified as important biological phenomena, but their conservation remains a major challenge. The Mongolian Gobi is one of the last refuges for the Asiatic wild ass (Equus hemionus) and other threatened migratory mammals. Using historic and current distribution ranges, population genetics, and telemetry data we assessed the connectivity of the wild ass population in the context of natural and anthropogenic landscape features and the existing network of protected areas. In the Mongolian Gobi mean biomass production is highly correlated with human and livestock density and seems to predict wild ass occurrence at the upper level. The current wild ass distribution range largely falls into areas below the 250 gC/m2/year productivity isoline, suggesting that under the present land use more productive areas have become unavailable for wild asses. Population genetics results identified two subpopulations and delineated a genetic boundary between the Dzungarian and Transaltai Gobi for which the most likely explanation are the mountain ranges separating the two areas. Home ranges and locations of 19 radiomarked wild asses support the assumed restricting effects of more productive habitats and mountain ranges and additionally point towards a barrier effect of fences. Furthermore, telemetry data shows that in the Dzungarian and Transaltai Gobi individual wild ass rarely ventured outside of the protected areas, whereas in the southeast Gobi asses only spend a small fraction of their time within the protected area network. Conserving the continuity of the wild ass population will need a landscape level approach, also including multi-use landscapes outside of protected areas, particularly in the southeast Gobi. In the southwest Gobi, allowing for openings in the border fence to China and managing the border area as an ecological corridor would connect three large protected areas together covering over 70,000 km2 of wild ass habitat.  相似文献   

17.
Understanding spatial and temporal patterns of species is a prerequisite for successful species and habitat conservation. Spatial variation in breeding sites of four gull species was studied in southern Finland in an oligo-mesotrophic lake complex covering almost 50 km2 of water areas and 290 km of shoreline in three census periods in 1986-2004. Two of the species have declined and are regarded as red-listed in Finland (black-headed gull ridibundus and lesser black-backed gull L. f. fuscus) and two have increased (common gull L. canus and herring gull L. argentatus) in numbers during the past decades. The numbers of breeding pairs and the percentage similarity in the spatial distribution of pairs of each species in grid squares were compared between different census periods at resolutions of 0.25, 1 and 4 km2. The common gull showed very high percentage similarity between the different census periods and consequently low spatial turnover in nesting sites, whereas the red-listed species, particularly the black-headed gull, had much higher spatial turnover. The spatiotemporal dynamics of gull species should thus be taken into account in conservation planning. If site protection is based only on information of breeding gulls in one year, a large or even major proportion of the breeding red-listed gulls might be outside the protected areas after a few decades. Due to the large spatiotemporal variation of red-listed gulls, areas to be protected should cover a rather large proportion of a boreal lake, not only individual islets or islands.  相似文献   

18.
This study considers the selection of sites based on the densities of breeding waders that would be considered to be distributed widely across common habitats in Scotland: so-called ‘wider countryside’ species. Five methods to provide a hierarchical classification of sites are assessed. Fifty percent of the populations of redshank (Tringa totanus) and snipe (Gallinago gallinago) occur on just 2 and 4.5% of Scottish lowlands, respectively, yet neither are suitably protected by conservation measures and both would benefit from a carefully targeted approach to their conservation. Three species, lapwing (Vanellus vanellus), curlew (Numenius arquata) and oystercatcher (Haematopus ostralegus) are more appropriately considered to be dispersed species. We propose that, if the density of a breeding wader on a site exceeds the threshold level predicted for the top 1% of Scottish lowland for that species, and if the area of the site exceeds 1 km2 then that site be considered to be a key site for farmland waders. The minimum density (in pairs km−2) must exceed 16.8 for lapwing, 10.1 for oystercatcher, 6.1 for snipe, 7.5 for curlew or 3.6 for redshank.  相似文献   

19.
The Chinese alligator, Alligator sinensis, is on the verge of becoming extinct in the wild as a result of loss of natural wetlands in the lower Changjiang valley. Chinese alligators are only known from a small region in southeastern Anhui province, a fraction of its former distribution. Within this area, a 433 km2 reserve has been declared that contains 13 designated habitat sites totaling 41 ha. The sites consist of small ponds located within or adjacent to villages, are completely surrounded by rice fields, or are biologically marginal oligotrophic ponds set in low hills. Alligators are only present at 10 of the 13 designated sites, with the largest groups containing a maximum of 10-11 animals and one adult female. In recent years nesting is known from only four areas, but the eggs are routinely collected and hatchlings retained in the Anhui alligator breeding center. The total population of wild Chinese alligators is probably <130 and is declining at an annual rate of 4-6%. If present trends continue, the Chinese alligator will be the first species of crocodilian to become extinct in the wild in historical times. Conservation efforts need to focus on protection of remaining wetlands and wetland restoration, and the inclusion of Chinese alligators in the active management of protected wetlands sites throughout the species' historic distribution.  相似文献   

20.
Mitochondrial 16S rRNA sequences from morphological validated grouper (Epinephelus aeneus, E. caninus, E. costae, and E. marginatus; Mycteroperca fusca and M. rubra), Nile perch (Lates niloticus), and wreck fish (Polyprion americanus) were used to develop an analytical system for group diagnosis based on two alternative Polymerase Chain Reaction (PCR) approaches. The first includes conventional multiplex PCR in which electrophoretic migration of different sizes of bands allowed identification of the fish species. The second approach, involving real-time PCR, produced a single amplicon from each species that showed different Tm values allowing the fish groups to be directly identified. Real-time PCR allows the quick differential diagnosis of the three groups of species and high-throughput screening of multiple samples. Neither PCR system cross-reacted with DNA samples from 41 common marketed fish species, thus conforming to standards for species validation. The use of these two PCR-based methods makes it now possible to discriminate grouper from substitute fish species.  相似文献   

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