Dataset summarising observations of amphibians in estavelles springs

The dataset summarises observations of amphibians performed in springs and estavelles of the Classic Karst region (NE Italy). From June 2020 to January 2025 we performed repeated surveys in all the months of the year, August excluded, both during day and night, in 61 springs sites. We considered springs occurring in the four poljes that were likely to have the typical hydrological regime already described for estavelles. In each site the occurrence and breeding of amphibians was assessed visually by inspecting for at least 10 minutes all the possible shelters including the elements of the substrate. At each survey, for each spring, we recorded abiotic and biotic features that can be important in explaining amphibians’ use of aquatic sites. As abiotic features we recorded the maximum water depth, the intensity of water flow, if the site was emitting or absorbing, the morphology of the spring mouth, diversification of substrate, which can reflect the abundance of shelters. Water flow was differentiated in four categories by the same observer: 1= absent, 2= just occurring, 3= moderate, 4 =strong. Diversification of substrate was based on microhabitat heterogeneity, considering the percent cover of sediments (including organic matter) which was classified as follows: 1, no diversification, one single substrate element covering almost entirely the site; 2, poor diversification, occurrence of two different substrates that added together covered>90% of the spring; 3, quite diversified, at least three elements on the substrate, each of which covering 20-40% of the spring habitat; 4, highly diversified, four or more elements including leaves and branches. As biotic features we recorded the occurrence of aquatic and semi-aquatic macrophytes and the occurrence of individuals (both juveniles and adults) of the pike (Esox cisalpinus) which is the top predator fish of the system investigated.

本数据集汇总了意大利东北部经典喀斯特区域内，于泉水与喀斯特落水泉（estavelle）中开展的两栖类动物观测研究。2020年6月至2025年1月期间，研究团队于全年除8月外的所有月份，分日间与夜间对61处泉水样地开展了重复调查。本次调查选取了分布于4处喀斯特洼地（polje）内的泉水样地，这些样地具备已被文献报道的落水泉典型水文节律。在每处样地中，研究人员通过目视巡查至少10分钟，排查所有潜在庇护场所（包括底质各类组分），以评估两栖类的存在与繁殖情况。每次调查时，研究人员均记录了可用于解释两栖类对水生生境利用情况的非生物与生物特征。非生物特征包括：最大水深、水流强度、样地的出水/吸水属性、泉口形态，以及可反映庇护场所丰度的底质多样性。其中水流强度由同一名调查人员划分为4个等级：1级为无水流，2级为仅存在微弱水流，3级为中等强度水流，4级为强水流。底质多样性基于微生境异质性进行评估，同时考量沉积物（包括有机质）的覆盖占比，具体分级标准如下：1级为无多样性，仅存在单一底质组分且几乎完全覆盖样地；2级为低多样性，存在两种不同底质组分，二者总覆盖占比＞90%；3级为中等多样性，底质至少包含3种组分，每种组分的覆盖面积占样地生境的20%～40%；4级为高多样性，底质包含4种及以上组分，包括落叶与枝条。生物特征包括：水生与半水生大型植物（macrophytes）的存在情况，以及本次研究系统中的顶级捕食性鱼类——梭鱼（Esox cisalpinus）的成体与幼体个体存在情况。