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1.
Interactions between seabirds and longline fishing can cause incidental bird mortality and reduced gear efficiency. The potential for solving these problems by using a bird-scaring streamer line and a line shooter was investigated in commercial longlining in the northern Atlantic off the coast of Norway. We compared the bycatch rate of northern fulmars Fulmarus glacialis, the loss rate of baits to fulmars and the catch rates of fish target species among lines set with either of these mitigation measures, a combination of both and no mitigation measure. A total of 58,420 hooks were set in each of the four treatments. No birds were caught using the bird-scaring line alone and a single fulmar was caught when the bird-scaring line was used in combination with the line shooter. In contrast, 32 fulmars were caught in sets with no mitigation device and thirteen in sets with the line shooter alone. Losses of mackerel bait were reduced when the bird-scaring line was used, but not by using the line shooter alone. Longlines set with the line shooter reached 3 m depth 15% faster then lines set without the line shooter; beyond this depth sinking rates were similar (about 15 cm s−1). Fish catch did not vary significantly among setting methods. These results should also be applicable to the bycatch of Fulmarus spp. in demersal longline fisheries worldwide.  相似文献   

2.
Seabirds such as albatrosses and petrels are frequently caught in longline and trawl fisheries, but limited demographic data for many species creates management challenges. A method for estimating the potential biological removal (the PBR method) for birds requires knowledge of adult survival, age at first breeding, a conservation goal, and the lower limit of a 60% confidence interval for the population size. For seabirds, usually only the number of breeding pairs is known, rather than the actual population size. This requires estimating the population size from the number of breeding pairs when important demographic variables, such as breeding success, juvenile survival, and the proportion of the adult population that engages in breeding, are unknown. In order to do this, a simple population model was built where some demographic parameters were known while others were constrained by considering plausible asymptotic estimates of the growth rate. While the median posterior population estimates are sensitive to the assumed population growth rate, the 20th percentile estimates are not. This allows the calculation of a modified PBR value that is based on the number of breeding pairs instead of the population size. For threatened albatross species, this suggests that human-caused mortalities should not exceed 1.5% of the number of breeding pairs, while for threatened petrel species, mortalities should be kept below 1.2% of the number of breeding pairs. The method is applied to 22 species and sub-species of albatrosses and petrels in New Zealand that are of management concern, of which at least 10 have suffered mortalities near or above these levels.  相似文献   

3.
Longline fisheries have been responsible for the deaths of large numbers of seabirds worldwide. Two of the most difficult seabird species to deter from baited hooks are the white-chinned petrel (Procellaria aequinoctialis) and sooty shearwater (Puffinus griseus). Longlines with integrated weight (IW) sink faster than normal, unweighted (UW), longlines and have the potential to reduce the numbers of these species killed. The relative differences in the number of white-chinned petrels and sooty shearwaters killed on UW longlines and IW longlines containing 50 g/m beaded lead core were investigated in 2002 and 2003 in the New Zealand ling (Genypterus blacodes) autoline fishery. Effects on catch rates of target and non-target fish species, and operational aspects of the use of IW gear, were also assessed. A single bird scaring streamer line was deployed on all sets of longlines. In 2002 and 2003, compared to UW lines IW lines reduced mortality of white-chinned petrels by 98.7% and 93.5%, respectively. In 2003 IW lines reduced sooty shearwater mortality by 60.5%. Catch rates of white-chinned petrels (including on sets when no fatalities were recorded) by IW gear were low: 0.005/1000 hooks (UW: 0.4) and 0.01/1000 hooks (UW: 0.17) in 2002 and 2003, respectively. Equivalent rates for sooty shearwaters in 2003 were 0.06/1000 hooks by IW and 0.13/1000 hooks by UW. No albatrosses were caught on either line type in 2002; in 2003 a single Salvin’s albatross (Thalassarche salvini) was caught on UW gear. Both the number of ling and the mean masses of ling caught in 2003 by IW (mass: 189.3; CL95% 162.7-220.3 kg/1000 hooks) and UW (200.6; CL95% 178.2-225.9 kg/1000 hooks) longlines were similar statistically. Use of IW longlines and streamer lines in autoline fisheries should yield major conservation benefits to seabirds interacting with these fisheries worldwide.  相似文献   

4.
The population-level impact of seabird bycatch is difficult to assess because colony-of-origin is often unknown. As an alternative and complementary approach to ship-derived observations, we assessed the relative potential for bycatch of a known seabird population by quantifying spatio-temporal overlap with local fisheries. Common murres (Uria aalge) have been reported as the most abundant seabird inadvertently caught in Washington and British Columbia coastal gillnet fisheries. In 1999-2001, we tracked 48 common murres from Tatoosh Island, the closest colony to the fisheries, during post-breeding. Using capture-mark-recapture models, we estimated weekly murre movement probabilities to/from three strata (offshore of, centered around, and inshore of Tatoosh Island). Based on movement probabilities and population size, we projected strata- and week-specific murre abundance. We created an index of overlap by calculating the product of murre abundance × gillnet fishing effort as a function of strata and time. The majority of murres (80%) moved inshore, where fishing effort was consistently the highest, suggesting that up to 4000 Tatoosh murres were vulnerable to bycatch. Index scores in the inshore stratum were 5-25 times higher relative to the offshore and Tatoosh strata, respectively. Overlap was sensitive to phenology, as index scores increased by 50% when dispersal was shifted four weeks earlier, while a two weeks delay decreased scores by 20%. Until the long-term impact of cumulative mortality in gillnet fisheries is determined, we believe a precautionary approach is warranted in the inshore stratum where the potential for bycatch was highest. We advocate the use of visible netting in inshore fisheries, a proven solution that reduces murre bycatch while maintaining fishing efficiency.  相似文献   

5.
Despite the worrying conservation status of several albatross and petrel population, the long-term trends of many populations remain largely unknown and the causes of decline in many cases are known or very strongly suspected to be incidental mortality in fisheries. Here we combine long-term monitoring of population trends, breeding success and band recoveries to examine the past and current status of five species of albatrosses and giant petrels breeding at the same site: sooty albatross (Phoebetria fusca), light-mantled albatross (Phoebetria palpebrata), wandering albatross (Diomedea exulans), northern giant (Macronectes halli) and southern giant petrels (Macronectes giganteus) on Possession Island, Crozet archipelago. We identified three groups of trends over a 25-years period (1980-2005) suggesting common underlying causes for these species in relation to their bioclimatic foraging ranges. The Antarctic species - light-mantled albatross and southern giant petrel - appeared stable and increased recently, the Sub-Antarctic species - wandering albatross and northern giant petrel - declined with intermediate periods of increase, and finally the subtropical species - sooty albatross - declined all over the period. Breeding success, indicative of environmental conditions, showed two kinds of pattern (low and fluctuating versus high and/or increasing) which were consistent with oceanographic variations as found in a previous study. We present the analysis of fisheries-related recoveries, indicative of fisheries bycatch risks showing specific catch rates. No direct relationship between population trends and longline fishing effort was detected, probably because census data alone are not sufficient to capture the potentially complex response of demographic parameters of different life stages to environmental variation. This study highlights the contrasted changes of procellariiform species and the particularly worrying status of the subtropical sooty albatrosses, and in a lesser extent of Sub-Antarctic species.  相似文献   

6.
Small-scale fisheries provide over half the world’s wild-caught seafood, employ over 99% of its fishers, and are frequently promoted as a sustainable alternative to large-scale industrial fisheries. However, few studies have quantitatively examined how possible habitat impacts and non-target species composition vary across gears used in small-scale fisheries, as data are sparse and conservation efforts are largely focused on more iconic species. Here, we quantify and compare the ecosystem impacts of four fishing gears (lobster traps, fish traps, set gillnets, drift gillnets) used in small-scale fisheries of Baja California, Mexico, using at-sea observations and field experiments. Set gillnets had the highest overall impact on both non-target species and habitat, with discard rates higher than most industrial fisheries (34.3% by weight), and an estimated 19.2% of Eisenia arborea kelp and 16.8% of gorgonian corals damaged or removed within 1 m of the net path. Fish traps had the lowest discard rates (0.11%) while lobster traps and drift gillnets had intermediate discard rates (15.1% and 18.5% respectively). In contrast with gillnets, traps caused minimal immediate damage to gorgonian corals and rarely interacted with kelp. Results indicate that ecological impacts depend more on fishing gear type and habitat characteristics than the size of fishing vessels, calling into question broad generalizations that small-scale fisheries are inherently more sustainable than industrial fisheries. Our findings highlight the ecological impacts of artisanal gillnet fisheries as priorities for research, management, and conservation efforts in Baja California and other coastal areas.  相似文献   

7.
Satellite tracking devices were used to examine the at sea movements of southern and northern giant petrels from Macquarie Island during the Austral summers of 2005-06 and 2006-07. Time spent at sea for nine northern giant petrels (four breeding adults, five recently fledged juveniles) and 10 southern giant petrels (three breeding adults, one non-breeding adult, and six recently fledged juveniles) was examined in relation to marine protected areas and fishing activity in the area immediately adjacent to Macquarie Island in 2005-06, and in terms of the jurisdictions of Regional Fisheries Management Authorities (RFMOs) at a broader scale during both seasons. Breeding adult southern and northern giant petrels spent a large proportion of their time at sea in the Macquarie Island Marine Park (25% and 65%, respectively), primarily during chick rearing. Further from Macquarie Island, the most important foraging areas for adult giant petrels were the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) statistical sub-areas 58.4.1 and 88.1, where foraging activity was concentrated around the ice edge and the Polar Frontal Zone. Fledglings of both species spent time in the Marine Park immediately after fledging, before moving into international waters. We found significant temporal and spatial overlap in the areas used by recently fledged juvenile northern giant petrels and the areas utilised by the single trawler that operated in these waters during 2005-06. Adult giant petrels spent little time in RFMO waters other than those under the jurisdiction of CCAMLR, but fledgling southern and northern giant petrels spent considerable time (56% and 78% of total time at sea) on the high seas of the Pacific Ocean, in areas under the jurisdictions of the Commission for the Conservation of Southern Bluefin Tuna (CCSBT), the Western and Central Pacific Fisheries Commission (WCPFC), the Inter American Tropical Tuna Commission (IATTC) and the South Pacific Regional Fisheries Management Organisation (SPRFMO). Band returns indicate that the International Commission for the Conservation of Atlantic Tunas (ICCAT) and the South East Atlantic Fisheries Organisation (SEAFO) areas are likely to be extensively utilised by Macquarie Island giant petrels in the first three years after fledging. Overall, Macquarie Island’s giant petrel populations are well protected by marine reserves during the breeding season. However, after fledging birds move into RFMO areas that currently have low standards of observer coverage and by catch mitigation, and where fisheries related mortality is likely to pose a significant risk.  相似文献   

8.
Many existing parks are currently experiencing difficulties in achieving their conservation aims, yet they remain an important option for maintaining and enhancing the conservation of biological diversity and ecosystem processes. Critics have claimed that many national parks cannot continue to protect the biological resources within their borders, and the sustainability of these areas over the long-term is in question. Ways need to be found to strengthen those that are failing, and to understand and replicate those that are succeeding. This paper presents the empirical results from a systematic evaluation of how effectively six case study national parks and national park reserves in Canada and South Africa have been protecting ecological integrity. Several parks were effective at addressing the priorities for which they had monitoring data, however the effectiveness rating of each park decreased when all indicators, including those identified as priorities but lacking monitoring data, were analysed. This indicates that the parks had generally identified more priority indicators than they were actually able to address (for many reasons, including lack of budget or trained staff, managerial challenges). Overall, a systematic approach to evaluating ecological integrity in national parks is recommended as the managers of protected areas cannot be expected to conserve the biological diversity and ecosystem processes within their borders if they are unaware of the ecological status of the park’s biodiversity. The paper concludes with several practical recommendations for monitoring ecological integrity in national parks.  相似文献   

9.
Urbanization changes bird community structure during the breeding season but little is known about its effects on migrating birds. We examined patterns of habitat use by birds at the local and landscape level during 2002 spring migration at 71 riparian plots along an urban gradient in Cincinnati, Ohio, USA. Using linear regression, we examined variation in relative density, species richness, and evenness of four migratory guilds associated with natural land covers and building area at four scales (50, 100, 250, 500 m radial buffers). We also examined the influence of local vegetation using multiple regression models. As building area increased, riparian forests tended to be narrower and have fewer native trees and shrubs. In general, native birds were positively associated with tree cover (within 250-500 m of stream) and native vegetation, and negatively with building area (within 250 m); exotic species responded inversely to these measures. Short-distance migrants and permanent residents displayed the weakest responses to landscape and vegetation measures. Neotropical migrants responded strongest to landscape and vegetation measures and were positively correlated with areas of wide riparian forests and less development (>250 m). Resident Neotropical migrants increased with wider riparian forests (>500 m) without buildings, while en-route migrants utilized areas having a wide buffer of tree cover (250-500 m) regardless of buildings; both were positively associated with native vegetation composition and mature trees. Consequently, developed areas incorporating high native tree cover are important for conserving Neotropical migrants during stopover.  相似文献   

10.
We conducted a satellite tracking study of the endangered short-tailed albatross (Phoebastria albatrus) to determine post-breeding season distribution, the amount of time spent within exclusive economic zones of Pacific Rim countries, and assess factors affecting spatial and temporal overlap with commercial fisheries in Alaska. We obtained 6709 locations for 14 albatrosses (131-808 locations and 51-138 days of tracking per bird). Albatrosses ranged widely throughout the North Pacific Rim, spending the majority of time within the exclusive economics zones of Japan, Russia (Kuril Islands and Kamchatka Peninsula), and the United States (Aleutian Islands and Bering Sea, Alaska). We found evidence for gender and age-related differences in distribution and, therefore, potential interaction with regional fisheries. Overall, albatrosses spent the greatest proportion of time within the Alaska exclusive economic zone. Within Alaska, albatrosses occurred most frequently in fishery management zones that encompassed the Aleutian Islands, Bering Sea, and south of the Alaska Peninsula. Short-tailed albatrosses had the greatest potential overlap with fisheries that occurred along continental shelf break and slope regions, e.g., longlining for sablefish (Anoplopoma fimbria), where albatrosses occurred most often. Some birds, however, also made frequent excursions onto the extensive Bering Sea shelf, suggesting significant potential for interactions with the large-scale walleye pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus) fisheries. Alaskan longline fishing fleets have been proactive in using seabird deterrent devices, however, our data further emphasize that such efforts beyond the Alaska exclusive economic zone would provide a greater conservation benefit for this species.  相似文献   

11.
Oryza granulata, an upland wild rice species, represents an unique germplasm for possessing abilities of tolerance to shade and drought, immune to bacterial blight and resistance to brown planthopper. Although low degree of genetic variability has been revealed within its populations, little genetic information at the species level is available in determining rational conservation strategies. Here we used dominant DNA marker random amplified polymorphism DNA (RAPD) to assess the genetic variability among 23 accessions of O. granulata that collected from main distribution areas worldwide. Twenty decamer primers generated a total of 243 bands, with 83.5% of them (203 bands) being polymorphic. Calculation of Shannon index of diversity revealed an average value of 0.42 ± 0.25, indicating that O. granulata maintains a relatively high degree of genetic diversity on the species level. Analysis of genetic dissimilarity (GD) showed that genetic differentiation occurred among studied accessions, which supports the feasibility of current ex situ conservation strategies. We also suggested that information based on population studies, which could be achieved by international co-operation, is needed to conserve this widespread germplasm more effectively.  相似文献   

12.
Rare plants in coastal New England sandplains are often restricted to anthropogenically disturbed sites including plowed and mowed firelanes at the Manuel F. Correllus State Forest on Martha’s Vineyard. Little is known about pre-colonial rare plant habitat or how modern management impacts these species. To understand the factors influencing rare plant distribution, we examined the influence of vegetation structure, species composition, environmental characteristics and disturbance history on rare plant populations and potential natural habitat in the 2100-ha Forest. We sampled >100, 100 m2 plots - in firelanes and forested/shrubland areas - and conducted extensive searches for rare plants.Linum intercursum and Scleria pauciflora var. caroliniana were frequent in firelanes including in recently plowed areas, whereas Nabalus serpentarius, Sisyrinchium fuscatum, and Aristida purpurascens generally occurred in isolated, locally-abundant patches in firelanes not plowed for many decades. The former group may be characterized by an ability to rapidly establish following disturbances while the latter may take longer to establish and develop large populations. In some respects, rare plants were associated with environmental conditions reflecting the disturbance histories of sites they occupied (e.g., L. intercursum with lower duff depth and N. serpentarius with greater litter cover/depth).In forests and shrublands undisturbed for decades, rare plants only occurred on well-worn paths. Although scrub oak stands supported conditions more similar to those found in firelanes than other native vegetation types, disturbances - far more severe than those in forests/shrublands of the past century - are probably required to create suitable rare plant habitat in sandplain forests and shrublands.  相似文献   

13.
We integrated satellite-tracking data from black-footed albatrosses (Phoebastria nigripes; n = 7) and Laysan albatrosses captured in Alaska (Phoebastria immutabilis; n = 18) with data on fishing effort and distribution from commercial fisheries in the North Pacific in order to assess potential risk from bycatch. Albatrosses were satellite-tagged at-sea in the Central Aleutian Islands, Alaska, and tracked during the post-breeding season, July-October 2005 and 2006. In Alaskan waters, fishing effort occurred almost exclusively within continental shelf and slope waters. Potential fishery interaction for black-footed albatrosses, which most often frequented shelf-slope waters, was greatest with sablefish (Anoplopoma fimbria) longline and pot fisheries and with the Pacific halibut (Hippoglossus stenolepsis) longline fishery. In contrast, Laysan albatrosses spent as much time over oceanic waters beyond the continental shelf and slope, thereby overlapping less with fisheries in Alaska than black-footed albatrosses. Regionally, Laysan albatrosses had the greatest potential fishery interaction with the Atka mackerel (Pleurogrammus monopterygius) trawl fishery in the Western Aleutian Islands and the sablefish pot fishery in the Central Aleutian Islands. Black-footed albatrosses ranged further beyond Alaskan waters than Laysan albatrosses, overlapping west coast Canada fisheries and pelagic longline fisheries in the subarctic transition domain; Laysan albatrosses remained north of these pelagic fisheries. Due to inter-specific differences in oceanic distribution and habitat use, the overlap of fisheries with the post-breeding distribution of black-footed albatrosses is greater than that for Laysan albatrosses, highlighting inter-specific differences in potential vulnerability to bycatch and risk of population-level impacts from fisheries.  相似文献   

14.
Reports of sugarcane yield responses to silicon (Si), coupled with mounting evidence that elevated crop Si levels reduce both biotic and abiotic stresses, account for the interest in the Si nutrition of this crop. In terms of managing Si supplies to sugarcane in South Africa, uncertainties exist regarding, first, the reserves of plant-available Si in soils, and second, the reliability of soil-test methods for predicting Si availability. In this study, extractable Si was measured in 112 soils collected from sugarcane-producing fields in South Africa. Soils were selected on the basis of dominant soil types and included Inceptisols, Alfisols, Mollisols, Vertisols, Oxisols, Entisols, and Ultisols, varying widely in chemical properties, texture, and extent of weathering. Extractants employed were 0.01 M calcium chloride (CaCl2) and 0.02 N sulfuric acid (H2SO4). Silicon extracted with 0.02 N H2SO4 ranged from 2 to 293 mg kg?1, whereas with 0.01 M CaCl2 the range was 5 to 123 mg kg?1. With both extractants, extractable Si decreased significantly with decreasing pH, exchangeable calcium (Ca), and total cations. In soils with potassium chloride (KCl)–extractable Al+H levels of greater than 0.5 cmolcL?1, extractable Si levels were consistently low, suggesting that soluble Al is implicated in reducing plant-available Si levels. Extractable Si levels were not related to the Bache and Williams P-sorption indices of soils. In the second part of the investigation, sugarcane leaf Si concentrations from 28 sites were related to soil extractable Si levels. The CaCl2 soil test proved markedly superior to H2SO4 as a predictive test for leaf Si levels.  相似文献   

15.
The small Cape mountain zebra population in Gamka Mountain Nature Reserve represents a third of the entire gene pool of this endangered species and is thus vital for it’s conservation. Presently, management of this population is largely hands off, with the belief that it will grow to levels which will allow it to form a source for the mixing of mountain zebra stocks in the future. The growth of this population however, has been slow and we investigated the influence of habitat and fire on this growth. Firstly, we used a diffusion model to perform a population viability analysis. This analysis indicated that the population had a low probability of attaining quasi-extinction in the next 50 years (G = 0.0032). However, our findings indicated that less than 30% of the reserve was suitable for mountain zebra and that the preferred habitat would have to be burnt at unnaturally short intervals to sustain the present growth. We therefore argue that the risk of quasi-extinction to this population is greater than predicted and suggest that management options need to be implemented to reduce this risk. These options include; translocation to another protected area; acquisition of adjacent land; burning preferred habitat at unnaturally short intervals; forming a conservancy with adjacent landowners; leasing cultivated land for pasture. We suggest that only the latter two options are likely to stimulate mountain zebra population growth in the short term and that these should receive immediate attention.  相似文献   

16.
The bush dog (Speothos venaticus), listed as CITES Appendix 1 - vulnerable, is a small (5-6 kg), rarely seen canid from Central and South America. The World Conservation Union Canid Specialist Group (IUCN CSG) recommended that research with this species focus on their basic ecology so that a data-driven conservation strategy can be formulated. Information on the bush dog, however, has been lacking since standard field techniques have had little or no success with this species. The S. venaticus Status and Distribution Survey was developed in an attempt to use indirect methodologies to determine the bush dog’s conservation status in the wild, its current distribution, and identify ecological needs by correlating habitat types to bush dog sightings. Survey responses and literature generated a database with 399 historic bush dog locations recorded between 1834 and 2004. These locational records were used to update the species’ range extent map, an important conservation planning tool. With year and precision of data accounted for, we analyzed land use coverage at known locations where bush dogs have historically been reported to evaluate the likelihood that the species persists in the area today. In addition, these locations provided training data for generation of potential distribution maps (i.e., areas of occupancy) using ecological niche modeling (i.e., Maximum Entropy) and bioclimatic data. These analyses revealed that 20% of the historic bush dog locations are associated with fragmented or altered habitat. These results allowed the status of bush dog habitat to be re-evaluated and areas that require more intensive research and protection to be identified.  相似文献   

17.
Conservation diagnosis of ex situ techniques (e.g. releasing chicks by hacking) cannot be evaluated without quantitative assessment of the fate of individuals, mainly their survival and recruitment. Here we use a long-term monitoring at a large spatial scale of a hacking programme (i.e. chick translocations) for Audouin’s gulls in an uninhabited site so as to establish a new breeding patch and reinforce the metapopulation. The success of the programme relied on the assumption that birds tend to recruit to the site where they fledge (i.e. they were philopatric). Multi-state capture-recapture models applied to a large dataset (more than 43,500 resights at 30 colonies during 1999–2010) were used to evaluate the survival of released chicks and the probability of being philopatric. Adult survival was high, but juvenile survival was lower than that of wild gulls, suggesting that there was a cost associated with hacking only during their first year of life. As expected, most released birds returned to the hacking site, but very few (including immigrants from abroad) attempted to breed here. Dispersal was inversely correlated with distance from the hacking site and positively associated with the population size of the patch (i.e. conspecific attraction). Even though most hacking procedures met the ecological conditions to succeed, results clearly showed that the program failed to establish a new breeding site. The ability of prospecting and the attraction made by conspecifics at established sites may be a constraint for the success of hacking programs, particularly for social and nomadic species.  相似文献   

18.
There is increasing evidence that culture is an important determinant of behavior in some non-human species including great apes and cetaceans (whales and dolphins). In some cases, there may be repercussions for population biology and conservation. Rapidly evolving “horizontal” cultures, transmitted largely within generations, may help animals deal with anthropogenic change and even allow them to exploit it, sometimes with negative consequences for both the animals and humans. In contrast, stable “vertical” or “oblique” cultures, transmitted principally between generations, may impede adaptation to environmental change, and confound range recovery, reintroductions and translocations. Conformist stable cultures can lead to maladaptive behavior, which may be mistaken for the results of anthropogenic threats. They can also structure populations into sympatric sub-populations with distinctive cultural variants. Such structuring is common among cetaceans, among which sympatric sub-populations may face different anthropogenic threats or respond to the same threat in different ways. We suggest that non-human culture should be integrated into conservation biology when considering populations with such attributes, and also more generally by refining definitions of evolutionarily significant units and considering how cultural attributes may change our perspectives of non-humans.  相似文献   

19.
Physoplexis comosa and Primula glaucescens, endemic to calcareous grasslands of the Lombardy Prealps, northern Italy, are protected under Annex IV of European Community Directive 92/43/EEC. Seed germination dynamics of these species were studied with the aim of producing appropriate germination protocols for use in ex situ conservation. Seeds were collected from Monte Barro (922 m a.s.l.) and for Primula glaucescens from three additional sites in a more central part of its range (1217-2521 m a.s.l.). Physoplexis comosa germinated only in sterile in vitro conditions, in which germination percentages were extremely low without a supply of gibberellic acid (GA3; 1.7%); the optimum GA3 concentration was 100 mg l−1 (> 90% germination), with lower germination at higher doses of 250-500 mg l−1. Primula glaucescens germinated in both sterile and non-sterile conditions and, although total germination was not affected by GA3 concentration, doses of 10-500 mg l−1 acted equally to prompt earlier and more rapid germination. Primula glaucescens from Monte Barro was characterised by slower and poorer germination than from central sites.  相似文献   

20.
Little is known about genetic diversity and geographic origin of wheat landraces from Oman, an ancient area of wheat cultivation. The objectives of this study were to investigate the genetic relationships and levels of diversity of six wheat landraces collected in Oman with a set of 30 evenly distributed SSR markers. The total gene diversity, (HT), conserved in the three durum wheat (Triticum durum desf.) landraces (HT = 0.46) was higher than in the three bread wheat (Triticum aestivum L.) landraces (HT = 0.37), which were similar to Turkish and Mexican bread wheat landraces calculated in previous studies. Genetic variation partitioning (GST) showed that variation was mainly distributed within rather than among the durum (GST = 0.30) and bread wheat (GST = 0.19) landraces. Based on modified Rogers’ distance (MRD), the durum and bread wheat landraces were distinct from each other except for a few individuals according to principal coordinate analysis (PCoA). One bread wheat landrace (Greda) was separated into two distinct sub-populations. A joint cluster analysis with other landraces of worldwide origin revealed that Omani bread wheat landraces were different from other landraces. However, two landraces from Pakistan were grouped somewhat closer to Omani landraces indicating a possible, previously unknown relationship. Implications of these results for future wheat landrace collection, evaluation and conservation are discussed.  相似文献   

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