Population Ecology Of Litsea Glutinosa In Dongshan Island

This paper studied the population ecology of Litsea glutinosa, a native tree in Dongshan island, propagation and cultivation, etc. by statistical methods.The results of this paper are as follows:1.Initial investigations community of Litsea glutinosaon in Dongshan Island, found that the distribution of Litsea glutinosa in the island a very wide scope,Both in the films into communities of Fung Shui Woodland secondary, and in the Dimocarpus longan Park,or Casuarina shelterbelt forests or Pinus elliottii forests, can be found Litsea glutinosa. Especially in the woodlands, low-lying land along the ditch Litsea glutinosa saplings in common, Casuarina backbone in the coastal protection forest belt has some of the regional distribution.The secondary communities of Litsea glutinosa in Dongshan island coverage a wealth of vegetation. There are mainly Casuarina, Ficus microcarpa, Litsea glutinosa, Celtis tetrandra subsp.sinensis, Zanthoxylum avicennae, Pistacia chinensis, Scolopia chinensis , Schefflera octophylla, Litsearotundifolia var.oblongifolia and Bridelia tomentosa in tree layer,and Murraya exotica,Pandanus tectorius,Glochidion puberum,Adina pilulifera,Lantana camara,Ardisia crenata,Pittosporum tobira,Gardenia jasminoides,etc in Shrub layer.There are Smilax china L.,Sabia schumanniana Diels,Acanthopanax trifoliatus,Coptosapelta diffusa,Cocculus orbiculatus,Sageretia thea,Anodendron affine,Pueraria lobata,Rosa cymosa in fujimoto layer,and Arundinella anomala,Polygonum chinense,Ageratum conyzoides, etc. in Herb layer.By analyzing the association between populations in the three sample plots, found among populations in communities have better adaptability, some of populations have very strong negative correlation. Litsea glutinosa populations in the secondary environment of Dongshan island other populations of interspecific association is not strong, and even unrelated. This shows that the independence of the Litsea glutinosa populations is relatively strong, and the strong ecological adaptability, to take the artificial vegetation restoration is feasible.2.By analyzing the age structure of populations of Litsea glutinosa, found that the age structure of Litsea glutinosa populations in Shanzhi,Huangshan and Houyao all showed a progressive population, the number of seedlings of individual possession of absolute advantage. Through the preparation life table of the three samples of Litsea glutinosa populations, the analysis:(1)Litsea glutinosa populations only survival curve model in Shanzhi (NX=N0e-0.7994x (R=0.952),NX=N0x -3.3025 (R=0.945) ) and (NX=N0e -0.7384x (R=0.9866),NX=N0x -2.0285 (R=0.9342) ) survival curve in Houyao tends to DeeveyⅡtype, while the population model in Huangshan (NX=N0e-0.851x (R=0.8812),NX=N0x-3.1489 (R=0.9854) ) tends to DeeveyⅢtype more. This shows that all populations of the two village (Shanzhi and Houyao)-level mortality or less the same age, and Litsea glutinosa in Huangshan village seedling stage mortality in a large population.(2)Mortality curves show Litsea glutinosa populations in Shanzhi village of only two deaths peak: Litsea glutinosa populations in Huangshan village during the peak of death three times.. Population of Litsea glutinosa in Houyao have two deaths peak in the first peak of the population than the other two areas should be delayed one age class, occurred in the first age classⅡ. This kind of three populations of Litsea glutinosa not a recession phase of the peak of the last death, shows that the population growth does not decline to its physiological age, the population of the life cycle will continue to develop.(3)Survival analysis of the introduction of four functions: survival function, cumulative mortality function, the death density function and hazard rate function, Curve estimates suggest that population growth has a characteristic of Early growth and late stable.3.With the frequency and R-scale analysis of the spatial distribution pattern of the population of Litsea glutinosa in the three sample plots.(1)On the adoption of the 5m×5m, 10m×5m and 10m×10m sampling three different scales in Shanzhi, it was found in different sampling units, Litsea glutinosa populations are reflected in the cluster distribution, and in the 5m×5m sampling unit on a strong degree of aggregation. Litsea glutinosa populations in Shanzhi in general for the cluster distribution of seedlings, saplings of the highest level of aggregation,and stage tree to tree to the random distribution of the population gradually and evenly distributed pattern of development. Of the two locations Huangshan and Houyao populations of Litsea glutinosa only 5m×5m scale analysis of the pattern of distribution, reflect the same local populations of the two first-classⅠand classⅡgathered at the largest degree, followed by the gradual spread of the final distribution tends to uniform or random. Overall, according to Green's index and the proliferation of GI index I sort, gather strength for the Huangshan> Shanzhi> Houyao, while the negative binomial parameter k, Cassie value targets CA, proliferation index and poly Iδmass index m * / m to sort order of aggregation for Houyao> Huangshan> Shanzhi.(2)Analysis of the use of R-scale, the three plots of Shanzhi, Huangshan and Houyao the spatial distribution of the population belong to non-random distributionby the statistical test concluded with the calculation results. Gathered for the degree of order Houyao > Huangshan > Shanzhi, which is in front of the spatial distribution of the frequency analysis of two parameters k, Cassie value targets CA, proliferation index and poly Iδmass index m * / m the results were consistent.4.Hegyi competition index model used to calculate the size of the competition index. The results showed that: Litsea glutinosa intensity of intraspecific competition of the size of the order as follows: Shanzhi (4.69)> Houyao (1.34)> Huangshan (0.68), intensity of intraspecific competition are the basic objects as wood and reduced the increase in diameter at breast height. Three Litsea glutinosa sample populations of interspecific competition in order of strength were: Shanzhi Litsea glutinosa (4.69)> Celtis tetrandra subsp.sinensis (0.69)> Ficus microcarpa (0.29)> Zanthoxylum avicennae (0.18), Huangshan, Casuarina (1.39)> Litsea glutinosa (0.68)> Dimocarpus longan (0.06), Houyao village of Litsea glutinosa (1.34)> Celtis tetrandra subsp.sinensis (0.31)> Ficus microcarpa (0.17)> Casuarina (0.12)> Zanthoxylum avicennae (0.09). Litsea glutinosa in Shanzhi village of intraspecific competition intensity forecast, the forecast for the regression model y = 55.67x-1.44(R =0.987), in the object tree diameter at breast height from 2.5 cm to 22.5 cm in the course of, Litsea glutinosa intensity of competition was clear downward trend; object tree diameter at breast height of 22.5 cm or more, although the decline in competition intensity, but the decrease is very small, the basic stabilizing.5.Determined through experiments were as follows: about 165.1 grams of seed weight of 1000, seed moisture content for dried 9.77%; the peak period of seed germination is normally between 30-40 days, the outside world the best in the temperature between 25-30 degrees Celsius, and humidity, to a large. Natural seedlings of early transplant mortality, the latter reduced until a stable.If during this period to take appropriate shade, ground in addition to weeds, maintain soil moisture and other conservation measures, can effectively improve the survival rate.6.Based on the above findings, the following stocks to the restoration of responses:First of all, as far as possible to protect the ecological communities where have the population of Litsea glutinosa.The restoration and development of the Litsea glutinosa population focus of seedlings in the protection of saplings.Collect Litsea glutinosa seeds in the field, and nurture seedlings to reforest.Rationally use of natural seedlings of Litsea glutinosa, plant relocation, and expansion of its human population distribution.