Long-term measurements of algal biomass in Sycamore Creek, Arizona, USA (2011-2019)

The primary objective of this project is to understand how long-term climate variability and change influence the structure and function of desert streams via effects on hydrologic disturbance regimes. Climate and hydrology are intimately linked in arid landscapes; for this reason, desert streams are particularly well suited for both observing and understanding the consequences of climate variability and directional change. Researchers try to (1) determine how climate variability and change over multiple years influence stream biogeomorphic structure (i.e., prevalence and persistence of wetland and gravel-bed ecosystem states) via their influence on factors that control vegetation biomass, and (2) compare interannual variability in within-year successional patterns in ecosystem processes and community structure of primary producers and consumers of two contrasting reach types (wetland and gravel-bed stream reaches). This dataset was collected to understand changes of algal growth by month during the field season and same season in different years characterized by different hydrological regime. In 2009 and 2013, data was collected in both wetland reach and gravel reach to compare the difference of algal growth in two reach types in the same time of the year. Data collected in 1980s and 1990s include two reach types: riffle and run, and were also to understand the post-flood succession. As sample collection and processing methodologies changed over the course of the long-term study, methods specific to distinct sampling periods are provided.

本项目的核心目标为揭示长期气候变率与气候变化如何通过调控水文扰动格局，进而影响荒漠溪流的结构与功能。在干旱景观中，气候与水文过程紧密耦合，因此荒漠溪流尤为适于观测并解析气候变率与方向性变化的生态效应。研究团队开展两项核心研究：（1）阐明多年尺度的气候变率与气候变化如何通过调控植被生物量的相关影响因子，作用于河流生物地貌结构（即湿地与砾石床生态系统状态的分布占比与持久性）；（2）对比两类差异显著的河段（湿地河段与砾石床溪流河段）的生态系统过程、初级生产者与消费者群落结构的年内演替格局的年际变异性。本数据集的构建旨在解析野外调查季内逐月的藻类生长动态，以及不同水文情势特征年份的同期季节变化规律。2009年与2013年，研究团队在湿地河段与砾石床河段均开展了数据采集，用于对比同一时段内两类河段的藻类生长差异。1980年代与1990年代采集的数据涵盖急流滩与缓流段两种河段类型，其采集目标同样为解析洪水后的生态演替过程。鉴于长期研究过程中样品采集与处理方法历经调整，本数据集针对不同采样时段分别提供了对应的专属实验方法。