Disturbance Hydrology: Preparing for an Increasingly Disturbed Future

Abstract

This special issue is the result of several fruitful conference sessions on disturbance hydrology, which started at the 2013 AGU Fall Meeting in San Francisco and have continued every year since. The stimulating presentations and discussions surrounding those sessions have focused on understanding both the disruption of hydrologic functioning following discrete disturbances, as well as the subsequent recovery or change within the affected watershed system. Whereas some hydrologic disturbances are directly linked to anthropogenic activities, such as resource extraction, the contributions to this special issue focus primarily on those with indirect or less pronounced human involvement, such as bark‐beetle infestation, wildfire, and other natural hazards. However, human activities are enhancing the severity and frequency of these seemingly natural disturbances, thereby contributing to acute hydrologic problems and hazards. Major research challenges for our increasingly disturbed planet include the lack of continuous pre and postdisturbance monitoring, hydrologic impacts that vary spatially and temporally based on environmental and hydroclimatic conditions, and the preponderance of overlapping or compounding disturbance sequences. In addition, a conceptual framework for characterizing commonalities and differences among hydrologic disturbances is still in its infancy. In this introduction to the special issue, we advance the fusion of concepts and terminology from ecology and hydrology to begin filling this gap. We briefly explore some preliminary approaches for comparing different disturbances and their hydrologic impacts, which provides a starting point for further dialogue and research progress.

Combined effects of an anthropogenic (forest harvesting) and natural (extreme rainfall event) disturbance on headwater streams in New Zealand

“…Natural disturbance regimes are an integral component of forested stream ecosystems. However, anthropogenic activities are increasing the frequency and severity of these hydrological disturbances (Mirus, Ebel, Mohr, & H., & Zegre, N., 2017). It can be difficult to differentiate the impacts of anthropogenic disturbances from natural hydrological disturbances, as was the case in our study.…”

“…It can be difficult to differentiate the impacts of anthropogenic disturbances from natural hydrological disturbances, as was the case in our study. However, Mirus et al. (2017) noted "it may be more useful to consider how humans may or may not influence the severity and frequency of different disturbances, rather than to attempt to differentiate between strictly anthropogenic and non-anthropogenic disturbances".…”

Stormflow threshold behaviour in a subtropical mountainous headwater catchment during forest recovery period

“…The concept of threshold behaviour is expected to serve as a promising new tool, which can be applied to evaluate stormflow responses to forest recovery following ecological disturbances. Previous studies have examined the forest damage following natural disturbances such as bark‐beetle infestation, wildfires, typhoons and extreme drought (Mirus, Ebel, Mohr, & Zegre, ), which in turn generate associated changes in forest eco‐hydrological processes (Biederman et al, 2015; Ebel, Rengers, & Tucker, ; Rengers, McGuire, Kean, Staley, & Hobley, ; Zhang et al, ). In January and February 2008, most areas in southern China suffered extensively from an extreme ice and snow storm event (Chen & Sun, ; Li, ; Shao, Huang, Liu, Kuang, & Li, ; Stone, ; Zhou et al, ).…”

Using isotopes to understand the evolution of water ages in disturbed mixed land‐use catchments

“…However, so far, most catchment studies exploring water age have been conducted in relatively small (<10 km 2 ), long‐term observatories with limited human impact: Far fewer are in catchments that have been disturbed though agricultural intensification and urban development (e.g., Brauer, van der Velde, Teuling, & Uijlenhoet, ; Soulsby, Birkel, & Tetzlaff, ). Nevertheless, as the human population continues to rise, increasing proportions of catchments are indeed being subject to more intensive disturbance and are undergoing major land use change (Mirus, Ebel, Mohr, & Zegre, ). In such landscapes, understanding the evolution of water age and the changing hydrological behaviour of the system can be challenging (Yu et al, ), as land management has the potential to induce complex scale‐dependent change (Thompson et al, ).…”