Ecological consequences of shifting habitat mosaics within and across years in an intermittent stream

Intermittent streams that cease to flow during dry periods represent more than half of the global river network and are particularly common in arid and semi-arid regions. They are characterized by high spatial and temporal variability in aquatic habitat, forming a shifting habitat mosaic that supports diverse assemblages of native and endemic species. Climate projections for much of the world predict greater variation in precipitation and increasing drought severity, suggesting a need to better understand species’ responses to habitat variability within intermittent stream ecosystems. Here we explored changes in the distribution and abundance of aquatic vertebrates in response to a wide range of annual hydrologic conditions within a Mediterranean-climate intermittent stream in California. We conducted wetted habitat and vertebrate abundance surveys during the dry season for seven years, spanning both extreme wet and extreme dry annual precipitation conditions, and characterized the vari..., Dataset Collection
Wetted Channel Surveys
We conducted surveys of wetted habitat conditions from 2014 to 2021 (except 2020, due to Covid-19 restrictions) along the 5-kilometer study reach in Coyote Creek (Figure 1b). In 2014, we surveyed at the end of the dry season (i.e., September; Bogan et al. 2019). Beginning in 2015, we expanded the study to include monthly surveys from the onset of disconnection (typically July or August) through the end of the dry season (i.e., until the first autumn rainfall, typically October or November). The timespan within which surveys were conducted encompassed extreme low (2021: 263 mm) and high (2017: 1011 mm) precipitation years, including the final years of a statewide multi-year drought between 2012-2016, capturing the wide range of interannual hydrologic variability observed in the system.
Between 2014-2016, monthly wet-dry mapping surveys were conducted by field crews walking the channel with a handheld Garmin eTrex GPS unit (+/- 15 m accuracy) and ...,