North Temperate Lakes LTER Regional Survey Zooplankton 2015 - current

The Northern Highlands Lake District (NHLD) is one of the few regions in the world with periodic comprehensive water chemistry data from hundreds of lakes spanning almost a century. Birge and Juday directed the first comprehensive assessment of water chemistry in the NHLD, sampling more than 600 lakes in the 1920s and 30s. These surveys have been repeated by various agencies and we now have data from the 1920s (UW), 1960s (WDNR), 1970s (EPA), 1980s (EPA), 1990s (EPA), and 2000s (NTL). The 28 lakes sampled as part of the Regional Lake Survey have been sampled by at least four of these regional surveys including the 1920s Birge and Juday sampling efforts. These 28 lakes were selected to represent a gradient of landscape position and shoreline development, both of which are important factors influencing social and ecological dynamics of lakes in the NHLD. This long-term regional dataset will lead to a greater understanding of whether and how large-scale drivers such as climate change and variability, lakeshore residential development, introductions of invasive species, or forest management have altered regional water chemistry. Zooplankton samples were taken at approximately the deepest part of each lake, via a vertical tow with a Wisconsin net. Count of individuals and presence absence data for all lakes in study region are provided here.

北部高地湖区（Northern Highlands Lake District, NHLD）是全球少数拥有近一个世纪以来数百个湖泊周期性综合水化学监测数据的区域之一。伯奇（Birge）与朱迪（Juday）牵头开展了该区域首次全面的水化学评估工作，于20世纪20至30年代对600余个湖泊完成了系统采样。后续多家机构先后重复开展了此类调查，目前我们已获取多批次分年代的监测数据：1920年代（威斯康星大学，University of Wisconsin, UW）、1960年代（威斯康星州自然资源部，Wisconsin Department of Natural Resources, WDNR）、1970至1990年代（美国环境保护署，U.S. Environmental Protection Agency, EPA）以及2000年代（北温带湖泊长期生态研究项目，North Temperate Lakes, NTL）。作为区域湖泊调查组成部分的28个湖泊，至少被上述4次区域调查采样覆盖，其中便包含1920年代伯奇与朱迪的采样工作。这28个湖泊的选取依据是其景观位置与岸线开发程度的梯度分布，二者均为影响北部高地湖区湖泊社会与生态动态的关键控制因子。这套长期区域数据集将助力我们更深入地解析气候变化与变异性、湖岸住宅开发、外来入侵物种引入以及森林管理等大型驱动因子是否以及如何改变了区域水化学特征。研究人员采用威斯康星网（Wisconsin net）垂直拖捕的方式，在每个湖泊的大致最深水域采集了浮游动物样本。本数据集提供了研究区域内所有湖泊的浮游动物个体计数及物种存在-缺失数据。