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浙江大学学报（农业与生命科学版）
Journal of Zhejiang University (Agriculture and Life Sciences)  2021, Vol. 47 Issue (5): 598-606    DOI: 10.3785/j.issn.1008-9209.2021.01.091
Resource utilization & environmental protection     
Terrestrial habitats in Changxing Chinese Alligator Nature Reserve of Zhejiang and their effects on the egg laying of the female alligators
Zhenwei WANG1(),Jianqing LIN2(),Guoheng ZHONG2(),Li SUN2,Shengguo FANG2()
1.Administrative Office of Changxing Chinese Alligator Nature Reserve, Huzhou 313100, Zhejiang, China
2.Key Laboratory of Biosystems Homeostasis and Protection of the Ministry of Education/State Conservation Centre for Gene Resources of Endangered Wildlife, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
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Abstract  

In this research, we surveyed the habitat factors in different regions in the core area of Changxing Chinese Alligator (Alligator sinensis) Nature Reserve of Zhejiang Provinceand their effects on the egg laying of the female alligators during the breeding season. The results revealed that the female alligators preferred to build nests on the regions covered with dense bamboo groves or tall trees. Few nests were found on the regions dominated by weeds and with few tall dominant trees. Investigation on the habitat factors in different regions showed that the dry mass of litter per unit surface area, the height of dominant species and the surface slope were the three major factors that affected the female alligators to choose the site for nesting. The above results could provide references for the habitat optimal transformation, and for the novel habitat selection. Our results could also facilitate the development of conservation programs for Chinese alligator.

Key words： Chinese alligator (Alligator sinensis)      egg laying      terrestrial habitat      vegetation     
Received: 09 January 2021      Published: 27 October 2021
CLC:  Q-9  
Corresponding Authors: Shengguo FANG     E-mail: alligator_wangzhw@163.com;linjianqing@zju.edu.cn;sgfanglab@zju.edu.cn
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Zhenwei WANG
Jianqing LIN
Guoheng ZHONG
Li SUN
Shengguo FANG
Cite this article:

Zhenwei WANG,Jianqing LIN,Guoheng ZHONG,Li SUN,Shengguo FANG. Terrestrial habitats in Changxing Chinese Alligator Nature Reserve of Zhejiang and their effects on the egg laying of the female alligators. Journal of Zhejiang University (Agriculture and Life Sciences), 2021, 47(5): 598-606.

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http://www.zjujournals.com/agr/10.3785/j.issn.1008-9209.2021.01.091     OR     http://www.zjujournals.com/agr/Y2021/V47/I5/598


浙江长兴扬子鳄自然保护区陆地生境及其对母鳄产卵的影响

以浙江长兴扬子鳄省级自然保护区核心区为研究地点，在扬子鳄（Alligator sinensis）繁殖期间，调查不同陆地区域中的生境因子及其对母鳄产卵的影响。结果表明，扬子鳄在选择筑巢地点时存在一定的偏好性，母鳄会优先选择在茂密的竹林或高大的乔木林下筑巢，杂草分布且缺乏高大植被的区域则很难吸引母鳄将其作为产卵地。对不同区域生境参数的差异分析表明，地表单位面积枯落物干质量、地表坡度以及优势种高度是影响扬子鳄巢位选择的主要因素。本研究结果能帮助更好地完成现有扬子鳄栖息地的优化改造，并为未来寻找新的扬子鳄放归地点提供参考，对促进扬子鳄这一濒危物种保护工程的发展具有重要意义。


关键词： 扬子鳄,  产卵,  陆地生境,  植被 
Fig. 1 Distribution of the different nest-density regions in each adult alligator pool and the specific location of quadrats

繁殖池

Pool

分布区域

Distribution region

面积

Area/m2

筑巢次数

Nesting times

鳄巢密度/（次/m2）

Nest density/（times/m2）

密度等级

Density class

#1全部陆地 All the land25000.000 0未利用 Not used
#2中心岛 Centre island5240.076 9高密度 High density
北岸 North bank20300.000 0未利用 Not used
西北岸 Northwest bank2600.000 0未利用 Not used
东岸 East bank9800.000 0未利用 Not used
#3西北半岛 Northwest peninsula5560.109 1高密度 High density
南岛 South island151100.066 2高密度 High density
东北半岛 Northeast peninsula11250.044 6高密度 High density
北岛 North island9940.040 4高密度 High density
东岸 East bank66330.004 5低密度 Low density
北岸 North bank32500.000 0未利用 Not used
西岸 West bank22500.000 0未利用 Not used
南岸 South bank16700.000 0未利用 Not used
#13西半岛 West peninsula8660.069 8高密度 High density
南岸 South bank25490.035 4高密度 High density
中心岛 Centre island11340.035 4高密度 High density
东岸北 East bank north5110.019 6低密度 Low density
北岸 North bank13020.015 4低密度 Low density
东半岛 East peninsula13010.007 7低密度 Low density
东岸南 East bank south6000.000 0未利用 Not used
西岸 West bank20900.000 0未利用 Not used
#14西岛 West island3460.176 5高密度 High density
东岛 East island13460.044 8高密度 High density
北岸 North bank16830.017 9低密度 Low density
南岸 South bank18820.010 6低密度 Low density
东半岛 East peninsula2500.000 0未利用 Not used
西岸 West bank11300.000 0未利用 Not used
#16&17东岸南 East bank south14870.047 3高密度 High density
西岸 West bank420130.031 0高密度 High density
东岸北 East bank north13210.007 6低密度 Low density
南岸 South bank10700.000 0未利用 Not used
中心岛 Centre island8000.000 0未利用 Not used
#18北岸 North bank22060.027 3高密度 High density
中心岛 Centre island421100.023 8高密度 High density
南岸东 South bank east5710.017 5低密度 Low density
南岸西 South bank west4000.000 0未利用 Not used
西岸 West bank3000.000 0未利用 Not used
东南岸 Southeast bank2000.000 0未利用 Not used
Table 1 Regions with different nest densities in each adult alligator pool
Fig. 2 Vegetations in the core areaA. Typical vegetations covered by Pleioblastus amarus as the dominant species; B. Typical vegetations covered by Cinnamomum camphora as the dominant species; C. Typical vegetations covered by Salix babylonica as the dominant species; D. Typical vegetations without dominant species.
Fig. 3 Frequency of each vegetation type in different nest-density regionsClass 1 corresponds to Figure 2A; class 2 corresponds to Figure 2B; and class 3 corresponds to Figures 2C and 2D.

生境参数

Habitat parameter

自由度

Degree of freedom

样本数

Sample number

F值

F value

P值

P value

优势种高度 Height of the dominant species2453.2900.047
单位面积枯落物干质量 Dry mass of litter per unit area24510.8720.000
郁闭度 Canopy density2450.6110.548
地表坡度 Surface slope2453.3140.046
干扰度 Disturbance degree2450.8700.426
横向离水距离 Horizontal distance from water2450.0180.982
离水高度 Vertical distance from water2451.6870.197
通畅度 Unobstructed degree2452.6040.086
Table 2 Analysis of variance results of each habitat parameter in different nest-density regions
Fig. 4 Box plots of important habitat parameters

生境参数

Habitat parameter

判别函数系数

Discriminant function

coefficient

12
特征值 Eigenvalue0.9430.201

优势种高度

Height of the dominant species

0.432－0.349

单位面积枯落物干质量

Dry mass of litter per unit area

0.9160.352
郁闭度 Canopy density－0.0990.183
地表坡度 Surface slope－0.4170.048
干扰度 Disturbance degree0.1910.469

横向离水距离

Horizontal distance from water

0.0100.148

离水高度

Vertical distance from water

0.0880.259
通畅度 Unobstructed degree0.1281.133
Table 3 Standardized canonical discriminant function coefficients
Fig. 5 Category scatter plots of the quadrats using the canonical discriminant function1: Not used area; 2: Low density area; 3: High density area.
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