Population Dynamics, Habitat Selection, And Conservation Of Gloydius Shedaoensis In Snake Island, Dalian, China

From 2005 to 2006,based on the investigational field data and collectable material,we study the pit-vipers Gloydius shedaoensis that has the representation to the life on Snake Island in China and is an endangered poisonous snake by using wild animals investigation,statistical analysis,silver staining and immunohistochemical,the computer model simulation.The population dynamics,habitat selection,relation between edible birds and snakes,population viability analysis,protection and management of Gloydius shedaoensis are studied on the point of view from the population ecology and conservation biology.The main results in this paper were revealed as following:1.Population size and distribution of Gloydius shedaoensis at presentFor current,the population size of Gloydius shedaoensis is 20 281±590 and most of them are in the sixth ditch and the second ditch,which mainly distributes in the shrub and the meadow.In addition,the distribution of Gloydius shedaoensis is more at the edge of forest, pond,and roadside,nearby stone such as places,while smaller at the jungle and kudzu. Different age groups of Gloydius shedaoensis have different distribution area that the juvenile and the subadult mainly distribute in the shrub and meadow,the adult mainly distributes in the forest,and aged adult mainly in bare land and rock.The main factors of influencing the populations and distribution of Gloydius shedaoensis are food,the type of vegetation,water source and stone,etc.2.Basic parameters of the populationAt present,the sex ratio of female and male of population of Gloydius shedaoensis is 1.11:1.00,the number of effective populations is 15 074 and age structure is that the juvenile 9.66%,subadult 15.81%,adult 61.08%,and aged adult 13.45%.The instantaneous rate of increase and the finite rate of increase respectively are 0.020 4 and 1.0206.It is a stable population and population growth slowly.The estimate value of environmental capacity is 22750.3.Population dynamics changeThe number and distribution of Gloydius shedaoensis changed significantly in spring and autumn.Population has small fluctuation and distribution is permanent and in heaps.It has certain changes in the structure of the population that juvenile and subadult reduce the proportion and aged adult has an increasing proportion.The number growth speed is gradually slowing down;so,the need for further increasing the level of environmental capacity is necessary. 4.Habitat selectionIn order to obtain more opportunities to catch the edible birds,Gloydius shedaoensis has more choices the shrub and forest habitats in sunny and semi-shade semi-sunny,in general, which locate in upper slope location,higher elevation,slopes,moderate vegetation cover, proximity to the forest edge,roads and the mountain ridges.In order to obtain sufficient energy, Gloydius shedaoensis selects habitat conditions with higher temperature,moderate humidity and illumination intensity.It is the most important environmental factors that Gloydius shedaoensis habitat selection is forest edge,roads,mountain ridges and the type of vegetation. The main influencing factors of habitat selection are the availability of food and heat.5.The relationship between Gloydius shedaoensis and edible birdsCurrently edible birds of Gloydius shedaoensis have 9 Order,29 families,99 species,and passerine small birds(body length 20.00～10.00 cm) are the mains.Edible birds have higher population density at the bottom of ditch near the water meadows,bare land and shrub.Body length,number,distribution,the time,which arrives and pause on the island of edible birds influence Gloydius shedaoensis habitat selection and predation rate.Gloydius shedaoensis and edible bird's population dynamics show significant positive correlation.6.Gastrointestinal endocrine cells of Gloydius shedaoensis and their alimentary canal function adaptationArgyrophilic cells and 5-Hydroxytryptamine immunoreactive cells of Gloydius shedaoensis exist in all parts of digestive tract and have diverse morphology.The distribution of density curve is undee and the distribution density at gastric cardia;duodenum and rectum site is higher which demonstrate that unique diet is suitable for living environmental.7.Artificial feeding and energy metabolismThe snake can be longer suffered from hunger,resting metabolic rate(RMR) is low, energy metabolism relatively is slow,and the discharge peak is seven days after eating.Adult's digestion and absorption rate are higher,while,the juvenile and the subadult are lower. Artificial feeding liquid food can meet the individual needs of the growth and have a higher survival rate.8.Population viability analysisWhen the parameters of the estimative and forecast population number of Gloydius shedaoensis have been put into VORTEX 9.42 software,we can obtain the better fitting results with the present observation value.The existing management measures of nature reserve can assure this population stabilize in the level of environmental capacity for a long time,which make the extinct probability of this population be 0 within 100 years,but not make the population number obviously increase.The main factors of affecting population dynamics are environmental capacity,mortality and disaster.On the level of environmental capacity,it will have not a tremendous influence on population dynamics of Gloydius shedaoensis by capturing properly.Increasing the environmental capacity and reducing the mortality are the main measures of increasing the population number of Gloydius shedaoensis.Meanwhile,they will be important work contents of nature reserve in future.9.Endangered mechanisms and protection measuresAt present,Gloydius shedaoensis have a certain protection,and have a better basis of scientific research and management means,but species are still endangered.On the one hand, fluctuations of the external environment randomly interfere with the island ecosystems,the other hand,they loss their own genetic diversity and own life history character.Correctly handling the relationship among people,snakes and birds,the relations between protection and economic development,intensifying the research and the effective management,and raising the people's awareness of protection are the effective way of protecting Gloydius shedaoensis populations and restoring its resources.