Exploring the Mechamism of Species Endangerment and Conservation Strategy in the Rangtze River Drainage
Investigation of intraspecific morphological variation is critical for the understanding of evolutionary and ecological processes, and may provide insights for uncovering the roles of natural selection, gene flow, and genetic drift in the distribution and abundance of species diversity. In the present study, we analyzed statistically the patterns of variation of 13 morphological traits among 12 populations in three localities of an endemic orchid, Changnienia amoena. The results showed that, among the three localities, the mean value of all measured morphological traits is the highest in the Lushan populations. There is abundant variation at both the species and population levels. Coefficient of variation (CV) varied between 0.02 and 0.30 at the species level, and the CV values of reproductive organs were lower than those of vegetative structures. ANOVA analysis showed that there was significant difference in most morphological traits among the three localities. UP-GMA analysis showed that the populations in three localities were clustered into three main clades, the populations from Xinning and Lushan formed one clade, while the Shennongjia populations formed another clade. It is noteworthy that the Shennongjia populations were separated into two subclades corresponding to the populations at Longmenhe and Guanmenshan, respectively. This morphological differentiation is most likely a result of pollinator-mediated selection because this species is pollinated by different bumblebee species at these two sites. Pearson correlation analysis showed that high correlation occurred within the vegetative organs, reproductive organs, and be-tween them. These results have important implications for our understanding of the evolutionary processes and mechanism of C. amoena and might provide useful information for the conservation and management of this endangered orchid.
Large mammals such as Asiatic elephant (Elephas maximus), rhino (Rhinoceros sp.), golden monkey (Rhinopithecus roxellana), gibbon (Hylobates sp.), giant panda (Ailuropoda melanoleuca), Père David's deer (Elaphurus davidianus), sika deer(Cervus nippon), and brown bear (Ursus arctos) once lived in the Dongting Lake drainage area of the middle-lower reaches of Yangtze River. However, due to climate change, geomorphological change and human disturbance, these large mammals were extirpated from thearea. After humans settled in the Dongting Lake drainage area, human activity was the major cause of the ex-tinction of local mammalian fauna, especially human hunting, habitat loss to human settlements and land reclamation. Rhino and Asiatic elephant were extirpated or emigrated from the area during the late period of the Northern Song Dynasty while Père David's deer, golden monkey, gibbon, giant panda, sika deer and brown bear became extinct in the Dongting Lake Drainage Area in the late 19th century. According to our in-vestigations during past years, such a process of species extinction is still escalating. We recorded 21 national key protected mammals in the 30 nature reserves or forest parks in the Dongting Lake drainage area. Among those species, five species are critically endangered, six species are endangered and ten species are vulner-able. Primary causes that threaten the survival of mammals are habitat loss, environmental pollution, hunting, and competition for food or habitat among wild animals. Impacts of human activities on survival of presently endangered mammalian species are much greater than ever before. These threats should be considered when reintroducing Père David's deer to the Dongting Lake region. A suitable habitat with enough foods and space and no human disturbance, a healthy founder population under close monitoring, and active conservation measures based on community co-management will be prerequisites for successful re-establishment of the extinct Père David's deer in the Dongting Lake drainage area.
Uncontrolled trade in wildlife may lead to extinction or endangerment of wildlife resources. Theoretical analysis on the characteristics and impacting factors on wildlife trade will improve the management of wildlife trade. We analyzed the features of wildlife trade, excluding timber and ocean fishery trades, from the view points of biological, sociological, economic and culture aspects. Comparing with other trade, the trade in wildlife is characterized by its traditional, regional, directional, seasonal, dispersive, substitutable, positive feedback and supplemental features. We pointed out that biological factors such as population size, possibility of acquirement, body size, periodic fluctuation in population size, endurance to harvest, sub-stitutability all influence trade of wildlife. Sociological factors such as policy, law enforcement, social psy-chology, income and hunting technique, at the same time, culture and traditional customs also affect the form and range of trade in wildlife. It provides theory basis for the management in wildlife trade to study the bio-logical, sociological, economic and culture influences on wildlife trade.
Daily travel distance of primates is an important factor to evaluate their home range size. The effects of annual change in group size, human disturbances and weather on daily travel distance of a group in Sichuan snub-nosed monkey (Rhinopithecus roxellana) was studied for eight seasons from April 2001 to January 2003 in the Qianjiaping area of Shennongjia Nature Reserve, Hubei. The group was successively followed for 30 days every season. The group’s straight-line distance method was used to determine the daily travel distance of the group. Annual group size was investigated and information on human disturbance and weather was collected. The results showed that group size increased by 14% from 2001 to 2002. There was no difference in the daily travel distance of the group between the two years, suggesting that annual change in group size had little effect on daily travel distance. The group traveled a longer distance on days with hu-man disturbance than on days without in the same season. Multiple stepwise regression analysis showed that there was no relationship between the daily travel distance of the group, the proportion of time spent sunning and the proportion of cloud cover during the day in different seasons. The daily travel distance was nega-tively correlated with percent of time with rain or snow during the day in winter and spring but not in sum-mer and autumn, indicating that the group reduced daily travel distance during rainy or snowy days in winter and spring. The seasonal difference in effects of rain or snow on the daily travel distance may be related to reproductive features of the monkeys. The results suggest that human disturbance may have a harmful effect on the monkey population, and that long periods of precipitation in spring and winter can represent crises for the monkeys.
To improve the efficacy of population conservation of giant panda, and to further understanding of its life history and biology, we investigated the scent mark trees at giant panda breeding sites in Wanglang National Nature Reserve in the spring of 2004. Based on 36 surveys on 10 transects, we documented 24 scent mark trees. We recorded species, height, and DBH of 1801 trees on the ridges of possible panda breeding sites. We found 13 (54%) of the scent mark trees on ridges with forest on both sides and located in the center of panda habitat. Seventeen scent mark trees (71%) were distributed between the elevation of 2700-3000 m. Average DBH of scent mark trees was 37.2±17.8 cm, 22 (92%) trees were Abies fargesii var. faxoniana, and 23 (96%) had rough bark. Eighteen (75%) trees were marked with secretion of the crissal gland at an average height of 51.8±15.6 cm (center above the ground), and the remaining six were marked with urine at an average height of 64.5±14.5 cm (upper edge above ground). All the scent mark trees were found in Changbai Valley and Jiefang Valley. Therefore, these valleys are vital habitats of the panda population during the spring mating season. Based on our results, Wanglang Nature Reserve has enhanced giant panda protection by adding a new seasonal conservation station, improving the patrolling route, and increasing patrolling frequency.
Home range and habitat use of male Reeves’s pheasant (Syrmaticus reevesii) were studied during the winter of 2001/2002 and 2002/2003 in the Dongzhai National Nature Reserve, Henan Province. The results from five individuals of Reeves’s pheasant with over 30 relocations indicated the average size of home range was 10.03 ± 1.17 hm2 by Minimum Convex Polygon method, 8.60 ± 0.35 hm2 by 90% Harmonic Mean Transformation method, and 9.50 ±1.90 hm2 by 95% Fixed Kernel method. The winter range was smaller than that in the breeding season. The mean core area of the home range was 1.88 ± 0.37 hm2. Although the habitat composition of the core area varied greatly among individuals, conifer and broadleaf mixed forests, masson pine forests, fir forests, and shrubs together accounted for a large part of the habitats used. Habitat use within the study area was non-random, while habitats were randomly used within home ranges. Tree di-ameter at breast height, shrub height and coverage at 2.0 m dictated habitat use. The proximity between for-ests and shrubs were also important in providing refuge for the birds during the winter. Recommendations for conservation management include protecting the existing habitats in Dongzhai National Nature Reserve, in-creasing suitable habitat for Reeves’s pheasant through artificial plantations (e.g. firs), and restoring some parts of the large area of shrubs to forest.
Cathaya argyrophylla, an endangered species endemic to China, belongs to a single species genus of the pine family. Previous ecological studies indicated that the specific light requirement was one of the key limiting factors for its survival. Here we investigated the adaptation of its seedlings to different light availabilities created by different layers of black nylon net over the nursery site. The treatment of light avail-abilities included three levels, 100%, 45% and 3% of full daylight. The photosynthesis-related parameters under these three light environments were measured in summer and winter by the technique of gas exchange and chlorophyll fluorescence. Results showed that the low light environment decreased the maximal rate of photosynthesis（Pnmax）and carboxylation efficiency（CE）in the summer growing season, but the degree of depression depended on leaf age. Shading also caused a decrease of light compensation point（LCP）and light saturation point（LSP）to some degree. The accumulation of time that light intensity was higher than the light compensation point（LCP）in low light（3% daylight）on sunny days was not longer than six hours in an entire day. These results indicate that the growth of C. argyrophylla was greatly depressed under low light condi-tions. Its growth was the best under full daylight conditions and declined when light was lower than 45% daylight. The Pnmax, CE, LCP, and LSP in winter were lower than in summer, which may be attributed todown-regulation of the photosynthetic apparatus by the combined effect of low light and low temperature. Both current-year leaves and one-year-old leaves showed slight photoinhibition in winter under illumination, and moderate shade favored the adaptation to photoinhibition in winter. Compared with summer, the leaf of C. argyrophylla in winter dissipated a higher proportion of absorbed light energy in the form of heat, which could be indicated from the higher coefficients of non-photochemical fluorescence quenching (NPQ).
From 1998 to 2001, we investigated the relationship between population density, rut tactics and rut phases of Père David’s deer. We chose three groups of Père David’s deer as experimental animals: two groups from the Père David deer population in the Dafeng Père David Deer Nature Reserve, Jiangsu Province and one group from the Père David deer population in the Beijing Père David Deer Park, Beijing. We recorded population parameters and closure area, reproductive tactics, the events of changing harem master, the numbers and size of harems during the prophase, metaphase and anaphase of the rutting season. Three rut tactics - harem holding, sneak mating and lekking - were all recorded in these populations, though there were variations in the rut tactics among the three populations during the three phases. With Factor Analysis, we extracted two main components associated with rutting tactics: component 1 mainly represented the observation site, the number of deer and the density of deer, whereas component 2 mainly represented the phases of the rutting season. Spearman correlations showed that: (1) “sneak” tactics occurred during the whole rut season, while harem holding and lekking tactics only occurred during certain phases of the rut; (2) as population density increased, the stags tended to adopt lekking tactics. Thus, we conclude that “holding a harem” is the main rut tactic among Père David’s deer stags, however, stags also adopt different rutting tactics related to the phases of rut and the density of the population. We discuss the significance of rut behavioral adaptation toenvironment in Père David’s deer, and put forward ideas about conservation of Père David’s deer.
During 2001-2003, we conducted a survey on icefish resources in the Yangtze River basin, aiming to find out the impacts of habitat fragmentation on the population structure and dynamics of the species Hemisalanx brachyrostralis. By investigating the presence/absence of the target species in 86 water bodies, we analysed its temporal-spatial distribution patterns in relation to two important habitat parameters—water area and isolation. The results indicated that this species was mainly distributed in lakes affiliated with the mid-lower reaches of the Yangtze River, showing low incidence of occurrence (IO=21.3%, annual mean), frequent change in spatial pattern, and unstable population structure from year to year. Further analysis showed that both the IO and population stability of this species related positively to the water area index but negatively to the isolation index of the lakes studied. Binary logistic regression elucidated the presence/absence structure of H. brachyrostralis in the three years, showing presence of the species was positively related to water area index with high significance and negatively related to isolation index with significance. We conclude that the process of river-lake fragmentation, which results in the decrease of water area and increase of lake isolation, has major impacts on the spatial structure and dynamics of H. brachyrostralis along the Yangtze River basin.
The Bamboo Stem Fragment (BSF) distinguishing method is an important component of the currently widely applied panda population survey methodology. The threshold for differentiating individuals was based on a difference in average stem fragment size of 2 mm. Droppings from the same individuals were collected in Wanglang National Nature Reserve, and BSF values were measured and analyzed for accuracy assessment of the method. When integrated with other data from published references, the results show that the BSF method has a high correct distinguishing ratio (CDR). In Wanglang, the sample CDR was 92.9%. For the wild panda population of Wolong, the sample CDR was 71.2%, and for the captive panda population, the CDR was 77.6%. One hundred bamboo fragments are typically collected from each dropping. Fewer frag-ments will decrease the CDR. For example, with 30 fragments the CDR decreases by 3.7%, while with 34 fragments the CDR decreases by 2.6%.
Genetic diversity in a natural Caldesia grandis population in Hunan Province was assessed using RAPD markers. A total of 180 individuals from 30 maternal plants were assayed. Of the 100 RAPD primers screened, twelve produced highly reproducible bands. Using these primers, a total of 112 DNA fragments were generated with 79 (70.5%) being polymorphic. Analysis of molecular variance (AMOVA) show that a large proportion of genetic variation (76.9%) resided within families, while only a small proportion (23.1%) resided among families. Shannon index showed that total genetic diversity of maternal plants was 0.18, which was identical with the result of analysis of Nei’s gene diversity. NTSYS analysis indicated that the individual offspring from a single maternal plant could not be clustered together completely. The estimate of gene flow (Nm) among maternal plants was 0.83, indicating high gene flow among the maternal plants.
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