Combining pond margin sampling and SCUBA-diving effectively assesses biodiversity from shallow to deep zones

For each selected pond, four quadrats of 4 m2 and spaced at least 5 m apart were selected at 8 different water depths (32 quadrats per pond, 64 quadrats in total). These depths were: 0.25 m, 0.50 m, 0.75 m, 1 m, 1.5 m, 2 m, 2.5 m and 3 m, nearly reaching the maximum depth of both ponds. Quadrats were selected to be representative of all microhabitats present (e.g. emergent vegetation, submerged vegetation, open water, etc.). For water deeper than 1 m, a line and dropper was used to determine water depth. Each quadrat from a depth of 0.25 m to 1 m was marked using a implanted pole, and each quadrat from a depth of 1.5 to 3 m was marked using floating buoys to ensure a constant depth was maintained while sampling. Macroinvertebrates were sampled within each quadrat for a total of 5 min, using a standard pond net (30 cm X 30 cm, 1000-micron mesh size). Quadrats at depths of 0.25 m to 1 m were sampled by the surveyor standing in the water, and quadrats at depths of 1.5 m to 3 m were sampled by the surveyor using SCUBA-diving gear to reach the desired depth

针对每个选定的池塘，在8个不同水深下各选取4个面积为4平方米、间距至少5米的样方（quadrat），每个池塘共32个样方，总样方数为64个。所选用的水深分别为0.25 m、0.50 m、0.75 m、1 m、1.5 m、2 m、2.5 m和3 m，几乎覆盖两个池塘的最大水深。样方选取需尽可能代表区域内所有现存微生境，例如挺水植被、沉水植被、开阔水域等。对于水深超过1 m的区域，采用测绳与垂锤组合的方式测定实际水深。水深0.25 m至1 m的样方通过植入式标杆进行标记，水深1.5 m至3 m的样方则使用浮动浮标标记，以确保采样过程中维持预设的固定水深。使用标准池塘采样网（30 cm × 30 cm，网孔尺寸1000微米）对每个样方内的大型无脊椎动物进行为期5分钟的采样。水深0.25 m至1 m的样方由调查人员直接站在水中完成采样，而水深1.5 m至3 m的样方则需调查人员借助水肺潜水装备抵达指定水深后方可开展采样。