作为从水生到陆生过渡的脊椎动物, 两栖类是环境健康的重要指示类群。海南东寨港国家级自然保护区是以保护红树林为主的湿地类型自然保护区。目前人们对红树林湿地类保护区中两栖动物资源信息的掌握仍然比较缺乏。为了解海南东寨港国家级自然保护区两栖动物的群落特征及影响因素, 作者在区内布设了39条200 m长的两栖类固定调查样线, 并于2022年7月至2023年4月采用样线法开展了3轮夜间调查。结果表明: 保护区内分布有5科7种两栖动物, 包括优势种海陆蛙(Fejervarya moodiei)、次优种沼水蛙(Hylarana guentheri), 以及少见的泽陆蛙(Fejervarya multistriata)、黑眶蟾蜍(Duttaphrynus melanostictus)、饰纹姬蛙(Microhyla fissipes)、花姬蛙(M. pulchra)和斑腿泛树蛙(Polypedates megacephalus); 缓冲区和实验区内的每条样线平均记录到2.67种两栖类, 但核心区的多数样线(94.44%)只能记录到海陆蛙1种。区内近岸生境中能记录到这7种两栖类, 而近海生境中只栖居有海陆蛙。水体盐度和动物扩散是造成此空间分布格局差异的原因。区内两栖类群落组成也存在时间分布格局差异, 动物繁殖活动及环境温度(即气温和水温)的月际变化可能是导致此差异的重要因素。此外, 调查也发现潮高、湿度和水体pH值也显著影响区内两栖类多度变化。近岸两栖类的物种丰富度(P < 0.01)和多度(P < 0.01)均与海水盐度呈显著负相关; 其多度还与环境湿度(P < 0.01)和水体pH值(P < 0.01)显著负相关, 但与潮高(P < 0.01)、气温(P < 0.001)和水温(P < 0.001)显著正相关。本文报道了海南东寨港国家级自然保护区两栖类的群落组成与空间分布格局及影响因素, 丰富了对该保护区两栖动物资源的认识, 有助于红树林湿地类保护区两栖动物的保护与管理工作。

Aims: As vertebrates in the transition from aquatic to terrestrial life, amphibians are an essential indicator of environmental health. The wetland-type Hainan Dongzhaigang National Nature Reserve protects a major natural area of mangrove forests. Information on amphibian resources in mangrove wetland-type reserves remains limited. We aim to better understand the community characteristics and spatial distribution pattern of amphibians and their influencing factors in Hainan Dongzhaigang National Nature Reserve. Further, we provide a scientific basis for the conservation and management of amphibians in mangrove wetland-type reserves.

Methods: Three rounds of line transect surveys at night were conducted for amphibians in the reserve from July 2022 to April 2023. We used a total of 39 fixed sample lines with a length of 200 m in the reserve, with a spacing of more than 500 m between sample lines. Every night from 19:00 to 24:00 we surveyed each sample line once and repeated this routine for 3 days. The Mann-Whitey U-test analysis was applied to determine if there were differences in amphibian richness and abundance between the two sample areas. Differences in amphibian community composition between breeding periods were compared by Chi-square test. Pearson analyses were used to determine the relationship of each factor with amphibian abundance, richness, and Shannon’s diversity index.

Results: Seven species of amphibians from five families were distributed in the reserve, including dominant species Fejervarya moodiei, suboptimal species Hylarana guentheri, and unfrequent species Fejervarya multistriata, Duttaphrynus melanostictus, Microhyla fissipes, M. pulchra, and Polypedates megacephalus. Each sample line averaged a record of 2.67 amphibian species within the buffer and experimental zones, whereas the majority (94.44%) of sample lines recorded only a single species Fejervarya moodiei in the core zone. The seven amphibian species were recorded in the nearshore habitats of the reserve, while the near-sea habitats were inhabited only by Fejervarya moodiei. Species richness (P < 0.01) and abundance (P < 0.01) of nearshore amphibians were negatively correlated with seawater salinity. Further, their abundance was negatively correlated with ambient humidity (P < 0.01) and water pH (P < 0.01), but positively correlated with tidal height (P < 0.01), air temperature (P < 0.001), and water temperature (P < 0.001).

Conclusion: Our research shows that there are spatial differences in amphibian community composition, and seawater salinity and animal dispersal may contribute to these differences. We observe differences in amphibian community composition, with inter-monthly variations in breeding activities and ambient temperature being important factors. Additionally, we find that tidal height, humidity, and water pH significantly influence the variation of amphibian abundance in the reserve.