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1.
M. Nazre 《Genetic Resources and Crop Evolution》2014,61(6):1147-1158
Mangosteen (Garcinia mangostana L.), known as one of the most desirable tropical fruits of Southeast Asia, has been considered as an obligate agamospermous hybrid, thought to have arisen from two wild species, G. celebica L. (syn. G. hombroniana Pierre) and G. malaccensis Hook. f. However, this putative origin was based on a misidentification of G. malaccensis, which was confused for G. penangiana Pierre. Intensive field studies and molecular investigations based on internal transcribed spacer (ITS) sequence data of 22 samples were conducted, which included six samples of true G. malaccensis. Morphological observation shows that mangosteen highly resembles G. malaccensis, particularly in its vegetative and fruit characters, even sharing similar taste of ripe fruits. ITS data revealed that mangosteen shared more than 99 % of its sequence with G. malaccensis with a few accessions identical with wild populations in Peninsular Malaysia. Phylogenetic analysis revealed that clades of mangosteen are paraphyletic per se, but monophyletic if both mangosteen and G. malaccensis are grouped together. This show that mangosteen and G. malaccensis are so closely related that they should be combined together as one species. I propose two theories on the origin of mangosteen, first, that it is a hybrid of different varieties of G. malaccensis, and second, that it may be a product of multiple, superior selections from different populations of female trees of G. malaccensis originating in Peninsular Malaysia. 相似文献
2.
We analysed population trends of 24 wildfowl species in Mexico. Wildfowl numbers peaked during the early 1980s; lowest counts were recorded in 1997. Total wildfowl numbers (all species combined) and duck numbers (duck species combined) showed significant short-term (1981-2000) declines, while geese (goose species combined) showed a significant long-term (1961-2000) increase. Six wildfowl species suffered significant long-term declines, while four showed increases. During 1981-2000, 11 species declined, but none had significant increases. Redhead (Aythya americana), Mexican duck (Anas diazi), northern pintail (A. acuta) and black brant (Branta bernicla nigricans) should be given high conservation priority because of the high proportions of their North American populations in Mexico. Declining numbers of the later two species should trigger further investigation into the possibility of assigning them legal protection status. Other species with apparent declines in numbers should also be more closely monitored. For setting hunting limits in the country, the population status of each species should be accounted for, as well as the condition of breeding populations the previous spring. Other species with poor data or combined counts should be targeted for basic population studies. We suggest that the mid-winter counts be expanded to cover non-surveyed areas and conducted every year to more precisely detect wildfowl population change. Integrated to a site-selection analysis, the information presented here can provide the basis for a wildfowl conservation strategy in Mexico. 相似文献
3.
We compared the composition and structure of primary forest avifauna among primary forests, selectively logged forests and mixed-rural areas (e.g. villages and agricultural areas) of Peninsular Malaysia. We found that forests that were selectively logged at least 30 years ago contained only 73-75% of the 159 species of extant primary forest birds, with an increased proportion of dominant species. We estimated that only 28-32% of the primary forest species utilized the mixed-rural habitat, and that the number of species that bred in the agricultural landscapes might be even lower. The microhabitat of different species most affected their vulnerability to disturbance. Most small, arboreal frugivores and omnivores, and insectivores that fed from tree trunks, showed greater persistence in the mixed-rural habitat than ground dwelling bird species, which were affected most by disturbance. Resource abundance and variables that were closely related to forest disturbance such as the density of large trees, density of dead trees, canopy cover density and shrub volume influenced the distribution of the primary forest birds. Large primary forest reserves and a revision of short-cycle logging regimes (ca. 30 years) are needed if we are to conserve the lowland rainforest avifauna of Peninsular Malaysia and other parts of Southeast Asia. 相似文献
4.
Populations of rare or elusive large mammals are difficult to monitor, because they usually are secretive, solitary, occur at low densities, and have large home ranges. The global trend of generally decreasing large carnivore populations necessitates new, feasible, reliable, and cost-effective monitoring methods. We evaluate an index method developed for monitoring populations of moose (Alces alces) based on voluntarily and systematically collected observations from hunters, corrected for effort, for use in monitoring populations of large carnivores in Sweden. For our evaluation, we used independent estimates of minimum brown bear (Ursus arctos) densities from DNA-based scat surveys and brown bear distribution from mandatory reports from successful bear hunters. We verified that the index correctly reflected bear distribution. We also found strong linear relationships between the indices and the independent density estimates for bears at the scale of local management units (about 1000-2000 km2) in all three regional study areas (adjusted R2 = 0.88-0.60). Our results suggest that systematic, effort-corrected reports of observed animals can be an alternative and accurate monitoring method for the conservation and management of large mammals occurring over large areas when large numbers of willing volunteers are available (effort >30,000 h). 相似文献
5.
The quickening pace of modernisation in Malaysia is leading to a corresponding acceleration in man's impact on the natural environment of the region. It is shown that the tropical rainforest of Peninsular Malaysia is under heavy attack from a number of economic activities, the most important of these being tin-mining, the exploitation of the jungle for tropical hardwoods, and the removal of extensive areas of natural forest for agricultural expansion. Some of the ecological effects of these activities are briefly discussed and, by way of contrast, compared with man/environment relations in less technically and economically advanced societies. It is suggested that there is an urgent need to preserve, conserve and manage portions of Peninsular Malaysia's rainforest for the economic, aesthetic, recreational and ecological requirements of future generations. 相似文献
6.
Clarence L. Abercrombie Debra Davidson Christine A. Hope David E. Scott 《Biological conservation》1980,17(2):103-113
An investigayion was made into the status of the Morelet's crocodile Crocodylus moreleti Dumeril & Dumeril in Belize, a Caribbean nation of Central America. Juvenile animals were found to be rather common in isolated areas, but very few adults were observed; we believe this to be an indication of over-exploitation. Certain aspects of the hide-hunting-dealing enterprise are also examined, and it is concluded that if C. moreleti is to survive in any numbers, a policy of protection should be instituted. 相似文献
7.
The relationships between the Ni concentrations of the mudflat snails Telescopium telescopium and the surface sediments have not been reported yet from tropical intertidal areas. In this study, telescope snails and surface sediments were collected from 18 geographical sampling sites in intertidal areas of Peninsular Malaysia. The concentrations of Ni were measured in seven different soft tissues of the snails namely foot, cephalic tentacles, mantle, muscle, gill, digestive cecum, and remaining soft tissues. It was found that different concentrations of Ni were found in the different soft tissues, indicating different mechanisms of sequestration and regulation of Ni in these different tissues. By comparing the Ni concentrations in the similar tissues, spatial variations of Ni were found in the different sampling sites although there was no consistent pattern of Ni in these sites. The highest Ni variation based on the ratio of maximum to minimum values indicated that cephalic tentacle and foot were the main organs having high Ni variation. The use of correlation analysis and multiple linear stepwise regression analysis revealed that digestive cecum of T. telescopium could be used to reflect the Ni contamination of the sampling site. Also, the digestive cecum and gill were found to be the main bioaccumulation and storage sites for Ni. From the Ni accumulation patterns in all the populations investigated, tissue redistributions of Ni in gill was identified and could be proposed as an indicator of high Ni bioavailability and contamination in the sampling site. To our knowledge, this is the first and most comprehensive study on Ni accumulation in the different soft tissues of T. telescopium from tropical intertidal areas, in relation to the sediment data. 相似文献
8.
Jeffrey E. Moore Mark A. Colwell Ryan L. Mathis Jeffrey M. Black 《Biological conservation》2004,115(3):475-486
Spring distributions of black brant (Branta bernicla nigricans) are closely related to that of their primary food plant, eelgrass (Zostera marina). Using historical (1931-2001) brant data from Humboldt Bay, California, we show that proportional use of two main feeding areas in the bay strongly reflects food abundance. We used multiple regression to investigate whether the spatial relationship between brant and eelgrass holds at the flyway level. We related peak brant numbers at 11 staging areas in the Pacific flyway to the sites' Z. marina abundance and isolation from other important staging areas. We explained 90% of the variation in peak brant numbers across sites with these variables; isolated bays with high eelgrass abundance supported the most brant. Our results emphasize the importance of protecting large eelgrass habitats along the Pacific Coast, particularly in bays that are geographically isolated from other large staging areas. 相似文献
9.
In the UK, Euphydryas aurinia exists in fragmented habitat patches, and undergoes population fluctuations as a result of a larval parasitoid. Its range is declining in the UK and conservation is thought to require a landscape approach since populations spread over large areas in some years and contract to core breeding patches in others. We examined populations at a range of geographic scales using allozyme electrophoresis to look for evidence of gene flow and differences in genetic diversity among populations. Nationally, our FST value was 0.1542 but between population groups within the suspected colonisation range of the butterfly (ca. 20 km), FST values were not significantly different from zero. Genetic diversity in terms of number of alleles and heterozygosity was reasonably high in natural populations (He=0.267) but low in an introduced, isolated population. We infer that migration between closely spaced subpopulations (in a metapopulation) maintains a high genetic effective population size (large number of individuals in a population that contribute genes to the next generation) which offsets any local reductions in population numbers due to stochastic extinctions or parasitoid effects. We therefore conclude that effective conservation of the species must seek to provide networks of suitable habitat for groups of subpopulations, rather than maintaining habitat for isolated populations. 相似文献
10.
František J. Turček 《Biological conservation》1976,9(1):29-36
Saline marshes and steppes along the Danube in southern Slovakia lie on the northernmost border of the complex of Central European saline soils. The ecology of the saline localities studied is outlined on the basis of 48 bird and 18 mammal species. Some birds are confined to the saline localities studied because these are relatively well conserved and extensive rather than because they are saline. The root vole (Microtus oeconomus (Pallas)), known only from the area studied, and the lizard Lacerta vivipara Jacquin, living in isolated populations in mountainous areas, are the only known vertebrate relics. Some functional aspects of the animals studied are stressed. The saline localities are threatened by reclamation for agricultural use, by fire, drainage and lowering the underground water table, but primarily by pollution from both oily water and the dumping of refuse. In order to conserve these unique communities, total protection is needed except, perhaps, from cattle-grazing on the steppes. 相似文献
11.
M Elsbeth McPhee 《Biological conservation》2004,115(1):71-77
Long-term maintenance of captive populations followed by release of captive animals into the wild is one of many approaches to endangered species conservation. To assess captivity's effects on behavior, a simulated predator was presented and response behaviors measured in oldfield mice, Peromyscus polionotus subgriseus. The animals tested were from four populations collected from Ocala National Forest, Florida, and held in captivity for varying numbers of generations: 35, 14, 2, and 0 (wild caught). Results show (1) that the more generations a population has been in captivity, the less likely an individual is to take cover after seeing a predator and (2) variance in predator-response behaviors increases with generations in captivity. These results point to two ways in which captivity can compromise animal behavior and, in turn, the success of reintroduction programs. First, because individuals from populations that have been in captivity for multiple generations seek refuge less often than their wild counterparts, they might experience increased mortality in the wild due to predation. Second, increased behavioral variance could translate into decreased survivorship upon reintroduction. Therefore, more individuals will need to be released to reach the targeted wild population size. 相似文献
12.
Kimberly A Romain-Bondi Robert B Wielgus Wayne F Kasworm Wayne Wakkinen 《Biological conservation》2004,117(4):417-428
We used non-invasive DNA hair-sampling and catch per unit effort (CPUE: grizzly bears detected per 1000 trap nights) to estimate relative density and population size for a threatened grizzly bear population in the North Cascade Ecosystem of Washington and British Columbia. We used linear, logistic, and linear through the origin regression analyses to estimate the relationship between catch per unit effort and grizzly bear density for seven other grizzly populations. One grizzly bear was detected during 5304 trap nights (CPUE=0.19) over 3 years in the North Cascades. This CPUE was much lower than in the other seven populations, including two threatened grizzly populations in the Cabinet-Yaak and Selkirk Mountain Ecosystems. The logistic model (curvilinear relationship) best fit the data (R2=0.927), and yielded density and population size estimates of 0.15 bears/100 km2 (90% CI=0.03-0.71) and six bears (90% CI=1-27), respectively. Natural recovery seems unlikely for the North Cascade grizzly bear population because the population has a high likelihood of extinction due to demographic and environmental stochastic effects associated with extremely small population numbers. We recommend population augmentation. DNA hair-sampling and catch per unit effort models can be a useful method to evaluate relative densities and numbers of animals in small, threatened grizzly bear populations when sample sizes are too small to yield traditional mark-recapture analysis. 相似文献
13.
Soon Leong Lee Kevin K.S. Ng Chai Ting Lee Naoki Tani Jarkko Koskela 《Biological conservation》2006,131(1):72-92
To conserve a rare plant, conservation programs must be guided by the biological attributes of the species. What constitutes the most critical biological information for plant conservation has been the issue of discussion for the last 30 years. Most scientists promote an approach that is either ecological or genetic in emphasis. Ecological and genetic processes will often interact synergistically to influence the population viability and to determine the persistence of populations in the long run. Consequently, conservation management of plant species, in addition to ecological information, requires a robust understanding of underlying genetic processes as well as the variation within and between populations. Conservation has a cost and the resources available for conservation programs are always limited. Therefore, conservation management strategies should not only be scientifically justified but also practical in terms of resource availability. Shorea lumutensis is a rare and endemic dipterocarp in Peninsular Malaysia. A comprehensive research activity was initiated to assess the population ecology and population genetics of S. lumutensis to elucidate specific ecological and genetic requirements and subsequently to set conservation strategies and priorities. This paper is apparently the first attempt at applying both the ecological and genetic approaches into conservation management of a rare dipterocarp. In addition, this paper also attempts to link the gaps between conservation research and conservation management in a realistic manner. It is our hope that this study will serve as a model for the study of other rare dipterocarps which should be given priority for conservation. 相似文献
14.
Tien Ming Lee Navjot Sodhi Lian Pin Koh Susan L.-H. Lim 《Biological conservation》2005,122(2):193-204
Despite their vulnerability to forest disturbances in the Neotropics, the consequences of forest perturbation on mixed species flocks are poorly understood in the threatened Southeast Asian rainforests. We examined the effects of local-scale habitat disturbance on mixed species flocks along an escalating gradient of anthropogenic modification (i.e., forest interior, forest edge, and urban) in a sub-montane tropical rainforest in Peninsular Malaysia that is presently experiencing low intensity development. Mixed species flocks in the forest interior and forest edge habitats (9.3 ± 2.3 and 8.4 ± 2.3, respectively) had significantly higher number of species than those observed in the urban habitat (5.1 ± 1.7). Flock participation was influenced by environmental characteristics (e.g., canopy cover). Flocking species sensitive to habitat disturbance were likely to be from the Families Corvidae, Nectariniidae, and Sylviidae; had narrow to restricted altitudinal ranges; and were exclusively dependent on primary forest and understory microhabitats. We conclude that sub-montane mixed species flocks are affected by even small scale urbanization and that they, particularly with species richness as a parameter, can be used as effective ecological indicators. With the looming development pressure on the sub-montane/montane habitats in Peninsular Malaysia and the Southeast Asian region, urgent conservation actions are needed for the preservation of their biotas. 相似文献
15.
Beáta Újvári Thomas Madsen Tatiana KotenkoMats Olsson Richard ShineHåkan Wittzell 《Biological conservation》2002,105(1):127-130
Meadow vipers (Vipera ursinii) are small venomous snakes whose range in Hungary has been greatly fragmented by anthropogenic habitat disturbance (especially, agriculture). We obtained DNA from a total of eight Hungarian snakes. Genetic variability at the major histocompatibility (Mhc) class I loci was much lower for these snakes than for specimens from two large Ukrainian populations. Within two Hungarian populations for which we had multiple individuals, band-sharing indices were 100 and 84.6% (versus 63.3 and 57% for the Ukraine populations). The Ukrainian snakes also displayed more RFLP fragments than the Hungarian vipers (mean 13.7 versus 9.0, respectively). In combination with reports of birth deformities, chromosomal abnormalities and low juvenile survival, these data strongly suggest that the Hungarian vipers are experiencing inbreeding depression. Genetic diversity is still present in the Hungarian vipers but among rather than within populations. Given the very low numbers of animals, the only feasible strategy to increase the genetic diversity and to save the Hungarian vipers from extinction is to implement a captive breeding program based on genetically screened animals. 相似文献
16.
David Mallon 《Biological conservation》1983,27(4):373-381
The Ladakhl urial Ovis orientalis vignei has a limited distribution and in recent years has declined in number. The author made three visits to Ladakh to investigate the status of the urial in a major part of its range which had been little studied before. The objects of the survey were to ascertain in which parts of its former range the Ladakh urial still occured; to assess its numbers, the reasons for any decrease in numbers and the prospects for its future survival. It was found that the decline of this animal in Ladakh had taken place later than that of animals in other areas of the Himalayas, due in part to unique social conditions, and that a numerically much reduced but widely distributed population remains, and has reasonable prospects for survival. 相似文献
17.
A population viability analysis (PVA) was conducted to assess the minimum viable population (MVP) of the Atlantic Forest spiny rat Trinomys eliasi, a species threatened by habitat loss and restricted geographical distribution. Objectives were to suggest quasi-extinction thresholds, estimate minimum areas of suitable habitat (MASH) and MVPs, and compare results with the species’ current status. The computer package VORTEX was used. The model predicted sizes of 200 animals to achieve demographic stability, but buffering declines in genetic variability required populations of 2000 animals. Estimated MASHs were approximately 250 and 2500 ha for demographic and genetic stability, respectively. Mortality rate and mean litter size were the most sensitive parameters to changes in model assumptions. The protection of known populations and the search for extant populations are the first steps in conservation. T. eliasi's issue could help protecting the coastal shrubland ecosystem of Rio de Janeiro state. Observing IUCN's criteria for listing threatened species, it is suggested that T. eliasi should be ranked as vulnerable in red lists. 相似文献
18.
A.H. Harcourt 《Biological conservation》1981,19(4):269-282
The most detailed survey yet made of the numbers, distribution and conservation status of gorilla in the Bwindi Forest Reserve indicates a total population of 95–135 animals and a breeding population of only about 75. Within the Reserve the local people use an area more than twice as large as that used by the gorillas, and it is clear that gorillas avoid areas of human use. Conflict exists therefore between present human use of the reserve and gorilla conservation in Uganda. Small populations are especially vulnerable to extinction and since one of the primary aims of the Reserve is to provide a sanctuary for the gorilla, together with the other species of this immensely rich forest community, steps should be taken now to lessen the conflict. In particular it is recommended that the extent of all human use be reduced from the present 35–40% of the Reserve area to less than 20% as long as such use can be adequately controlled; if it cannot, National Park status should be considered; that no further access roads be built; that mechanised felling never be allowed; and that the Reserve be extended in the northwest to include extra gorilla habitat and to protect an important watershed in the region. 相似文献
19.
Five subspecies of markhor are said to occur in Pakistan. One subspecies, the so-called Chiltan markhor, was found to be a wild goat (Capra hircus), and the other four subspecies were reduced to two, the straight and flare-horned markhors.We made a survey of status and distribution throughout the range of the species in Pakistan and relied mainly on the literature for information on the animal in Afghanistan, Russia, and India. Markhor prefer fairly dry terrain near cliffs and they avoid deep snow and cold temperatures. These habitat requirements have restricted their range to mountains below altitudes of 2200 m in winter. Excessive hunting has reduced the populations to small, often isolated remnants. The total number of flare-horned markhor in eastern Afghanistan, and in the Chitral, Dir and western Swat districts of Pakistan, was estimated at around 1500. Farther east, along the upper Indus and its tributaries, are perhaps twice as many more (excluding some 250–300 in India). This number, coupled with the efforts made by the governments to protect the remnant, makes the prognosis for the survival of the subspecies good. Most straight-horned markhor occur south of the Khyber Pass in tribal areas which have no wildlife laws. Reduced to a number of small and scattered populations, comprising possibly fewer than 2000 individuals, the future of this subspecies is tenuous. 相似文献
20.
The 1995/1996 reintroduction of gray wolves (Canis lupus) into Yellowstone National Park after a 70 year absence has allowed for studies of tri-trophic cascades involving wolves, elk (Cervus elaphus), and plant species such as aspen (Populus tremuloides), cottonwoods (Populus spp.), and willows (Salix spp.). To investigate the status of this cascade, in September of 2010 we repeated an earlier survey of aspen and measured browsing and heights of young aspen in 97 stands along four streams in the Lamar River catchment of the park’s northern winter range. We found that browsing on the five tallest young aspen in each stand decreased from 100% of all measured leaders in 1998 to means of <25% in the uplands and <20% in riparian areas by 2010. Correspondingly, aspen recruitment (i.e., growth of seedlings/sprouts above the browse level of ungulates) increased as browsing decreased over time in these same stands. We repeated earlier inventories of cottonwoods and found that recruitment had also increased in recent years. We also synthesized studies on trophic cascades published during the first 15 years after wolf reintroduction. Synthesis results generally indicate that the reintroduction of wolves restored a trophic cascade with woody browse species growing taller and canopy cover increasing in some, but not all places. After wolf reintroduction, elk populations decreased, but both beaver (Caster canadensis) and bison (Bison bison) numbers increased, possibly due to the increase in available woody plants and herbaceous forage resulting from less competition with elk. Trophic cascades research during the first 15 years after wolf reintroduction indicated substantial initial effects on both plants and animals, but northern Yellowstone still appears to be in the early stages of ecosystem recovery. In ecosystems where wolves have been displaced or locally extirpated, their reintroduction may represent a particularly effective approach for passive restoration. 相似文献