Ecological Research Of The Beal's Eyed Turtle(Sacalia Bealei) At Huboliao National Nature Reserve,Fujian,China

The Beal's eyed turtle(Sacalia bealei) is a species endemic to China, distributed at Guangxi, Guangdong, Fujian, Anhui, Guizhou, Jiangxi Province and Hong Kong. Though S. bealei has been listed as endangered by IUCN, the research on their field ecological and breeding characteristics is still rare. Therefore we conducted systematic field research on the ecology of S. bealei between July 2014 and October 2015 at Huboliao National Nature Reserve of Fujian Province. 1. The relative population density and habitat selection of S. bealeiLocal interview and cage trapping were performed to investigate their population distribution and density. Two adult and three immature turtles were trapped in primary tributary, with none captured in secondary tributary and the main stream through 1660 cage days' s effort. So the relative population density of S. bealei was 0.0030 per cage day and the catching population density of S. bealei was 0.8/km at Huboliao National Nature Reserve. Local interview also indicated that S. bealei was mainly captured in primary tributary while few captured in the main stream by local residents. Therefore the population of S. bealei mainly distributed in primary tributary of the stream.Plots survey were preformed to compare the variation of 21 ecological factors among the main stream, primary tributary and secondary tributary. Thirteen factors showed significant difference between the primary tributary and main stream, while 16 factors showed significant difference between the primary and secondary tributary. Therefore, the habitat of primary tributary preferred by S. bealei was significantly different from that of main stream or secondary tributary. The habitat characteristics of the primary tributary were shown as following: biggish distance to human disturbance(250.17 ± 27.03)m, medium elevation(276 ~ 389)m, mild slope(18.50 ± 2.21)°, medium water depth(3.86 ± 0.17)m, biggish canopy density(50.10 ± 3.56)%, higher fruiter abundance(1.40 ± 0.20)/m2, biggish thickness of deciduous leaves(4.97 ± 0.16)cm, stony substrate [2(0)], the largest number of stone caves(0.26 ± 0.02)/m2 and greatest percentage of exposed stones(47.10 ± 2.27)%, higher density(5.03 ± 0.35)/m2 and species number of benthos(3.97 ± 0.26)/m2.We studied the micro-habitat selection of S. bealei(6?3?) in primary tributary though radio-telemetry techniques. Ten ecological factors including water depth, stone caves, density and species number of benthos, obscured object type, fruiter abundance, substrate type, vegetation type, percentage of exposed stones and woody plant density were significantly different between usage plots and control plots in both breeding and non-breeding period, while the former eight ecological factors were extremely significantly different. The principal components analysis was applied based on the year-round usage plots, and the result indicated that the former six principal components could explain 76.74% in which the “concealment factor” including number of stone caves, water depth, obscured object type, crown density, the “food factor” including number of benthos species, number of benthos density and fruiter abundance and “flow factor” including stream width and flow water speed played important roles in micro-habitat selection of S. bealei. 2. Home range of S. bealeiWe located 770 effective activity sites of 9 individuals(3?6?) during the research period. We defined the distance between the most remote two points among all the activity sites of each turtle as linear home range and computed the home range by the method of 95% minimum convex polygon and core home range by the method of 50% fixed kernel estimator with the help of Home Range Tools for Arc GIS 9.X. The result indicated that the linear home range of S. bealei was 184.89±25.98 m, the home range was 6256.91±1426.56m2 and the core home range was 892.01±205.86m2. We compared the sexual difference of home range between breeding and non-breeding period based on 6 S. bealei's(3?3?), and the results showed that female turtle's home range(6560.29±1232.78m2) was significantly larger than male turtle's home range(2033.05±455.47m2)(P=0.026) and female turtle's core home range(1128.81±189.16m2) was also significantly larger than male turtle's core home range(468.95±102.28m2)(P=0.037) in breeding period while no difference between female(1058.30±234.43m2; 212.60±51.40m2) and male(1112.14±207.33m2; 231.43±39.99m2) turtle's home range(P=0.872) and core home range(p=0.787) in non-breeding period. 3. Breeding research of S. bealei at fieldThe spawning period of female S. bealei was between middle April and middle June, mainly in May. They preferred to nest and lay eggs at rainy days. We discovered 6 female turtles' spawning action and witnessed 3 turtles' whole spawning procedure by direct observation, and the whole procedures included 5 different periods, including going ashore, digging nest, laying eggs, covering nest and returing water. The female turtles needed to crawl 21.33±4.69 m to find a proper nest site and could crawl 42.67±7.18 m to finish the whole spawn process which may last 4-10 hours. Female turtles might use 40-60 minutes to dig a nest and 8-10 minutes to lay eggs. Some turtles could spend several times to go ashore until finally found a proper nest site. For example turtle(15?) spent 3 times to go ashore from 17 May to 31 May and her whole procedure lasted 15 days.We discovered 13 eggs in 6 nests, and the clutch size was 2.2±0.3 eggs per nest. The average major axis of egg was 450.5±1.00 mm, average minor axis of egg was 23.20±0.50 mm, and average egg weight was 14.8±0.8g. Ten eggs showed fertilization spot which indicated the fertility rate was 76.9%. Seven infant turtles hatched successfully which indicated the incubation rate was 53.8%. The incubation period was 85—108d, and the average incubation period was 94.7±2.7d(n=7); the incubation temperature was 17.51-29.64 ?, and the average incubation temperature was 25.08±0.13 ?(n=7); the incubation cumulative temperature was 2152.2-2627.64??d, and the average incubation cumulative temperature was 2373.18±55.42??d(n=7). The average body weight of hatching turtles was 9.7±0.6g, with their average carapace length, carapace width, body height, plastron length and plastron width was 40.10±0.60 mm, 33.30±1.50 mm,17.40±0.60 mm, 31.60±0.60 mm and 25.40±0.80 mm respectively. The marginal shell of hatching turtles was soft, their carapace color was dark yellow and their eye spots color was bright green. The eye spots were bilaterally symmetrical, and linked together at each side. The yolk was absorbed completely after 7-10 days with plastron closed. Five hatching turtles survived after yolk was absorbed successfully among the 7 hatched turtles, so the survival rate of hatching turtle in 10 days was 71.4%.We treated the nests as usage plots(n=6) and located other sites that existed random distance on longitude and latitude with the nests as control plots(n=6). The test of ecological factors' difference between usage and control plots indicated that crown density(P=0.032), soil hardness(P=0.049), coverage degree(P=0.040) were significantly different and thickness of deciduous leaves(P=0.002) was extremely significantly different among 18 ecological factors which indicated that S. bealei preferred the site with lower crown density(36.67±9.80%), more number of vegetation species(10.67±0.71), bigger thickness of deciduous leaves(8.17±0.60cm), lower bushwood height(1.46±0.43m) and 1-20 vegetation per m2 as their nest sites.The result of principal component analysis indicated that the former 5 principal components could explained 88.63% variance in which the physical and chemical factors including soil hardness and soil salinity, the concealment factors including vegetation height, vegetation cover, vegetation density, number of vegetation species, crown density, the vegetation factors including distance to arbor and vegetation type would play an important role in nest site selection of S. bealei.