Fish densities sampled by Dual Frequency Identification Sonar (DIDSON) within Artificial Seagrass Units (ASU) in Back Sound, NC from June to October 2018

To parse the ecological effects of habitat area and patchiness on faunal community structure and dynamics of estuarine nekton, we employed artificial seagrass unit (ASU) landscapes at a scale relevant to habitat fidelity of common fish and macroinvertebrates in our temperate study system, Back Sound, NC. These ASU landscapes were designed along orthogonal axes of artificial seagrass area (i.e., percent cover of each landscape = 10-60 percent) and fragmentation per se (i.e., percolation probability; 0.1-0.59) to delineate their independent and interactive effects on seagrass fish communities.

To examine potential differences among faunal responses to habitat configuration within structured habitat (i.e., artificial seagrass) versus matrix habitat (i.e., sand/mudflat) within the borders of the landscape footprint, fish densities (catch per unit effort; CPUE) were sampled by Dual Frequency Identification Sonar (DIDSON) at three locations within each landscape from June to October 2018. Fish densities were sampled within the largest ASU patch of each landscape (“largest patch”) and at two locations within the matrix: 1-m away from the largest patch (\"near-patch\") and bisecting the largest interpatch distance (\"interpatch\"). Interpatch samples were not taken in landscapes with 0.59 percolation probability, as they only had one patch.

DIDSON samples were collected by Drs. F. Joel Fodrie, James W. Morley, and Amy H. Yarnall for the Estuarine Ecology Laboratory of the University of North Carolina at Chapel Hill’s Institute of Marine Sciences.

为厘清栖息地面积与斑块化程度对河口自泳生物（nekton）群落结构及动态的生态效应，本研究在温带研究系统——北卡罗来纳州巴克湾（Back Sound）中，采用与常见鱼类及大型无脊椎动物生境保真度相匹配的尺度构建人工海草单元（ASU）景观。本研究沿人工海草面积（即各景观的盖度占比为10%~60%）与固有破碎化程度（即渗流概率，取值范围0.1~0.59）两个正交轴设计实验景观，以阐明二者对海草鱼类群落的独立效应与交互效应。

为探究结构化生境（即人工海草）与景观覆盖区内基质生境（即沙质/泥质滩涂）中动物群落在生境配置响应上的潜在差异，本研究于2018年6月至10月期间，采用双频识别声呐（DIDSON）在每个景观内的3个采样点开展鱼类密度（单位捕捞努力量渔获量，CPUE）采样。采样点位分别设置于每个景观内最大的人工海草单元斑块（"largest patch"）中，以及基质生境的两个位置：距最大斑块1米处（"near-patch"），以及平分最大斑块间距的位置（"interpatch"）。对于渗流概率为0.59的景观，由于其仅存在1个斑块，因此未布设斑块间采样点。

本研究的双频识别声呐采样工作由北卡罗来纳大学教堂山分校海洋科学研究所河口生态学实验室的F. Joel Fodrie、James W. Morley及Amy H. Yarnall博士完成。