The Development and Application of Uniform Hydroseres in Riparian and Wetland Restoration: A Means of Increasing Resolution in the Design Phase and Enhancing Success in the Construction Phase
John Giordanengo1
1AloTerra Restoration Services, LLC, Fort Collins, USA; john@aloterraservices.com.
The distribution of plants across riparian areas is influenced by the frequency of flood disturbance, groundwater hydrology, soil conditions, shade, and other variables. The consistency of these variables over space and time can lead to the development of predictable hydroseres (i.e., zones) across floodplains. However, a consistent approach to defining these hydroseres, especially in a restoration setting, is lacking. Hoag and Fripp (2005) defined riparian zones for southwest riparian systems, based on flood return intervals. Merritt et al. (2010) developed vegetation-flow response guilds, grouping species with shared traits such as life history, reproductive strategy, morphology, and adaptations to fluvial disturbance & water availability. Restoration practitioners are tasked to define and communicate riparian designs for a broad spectrum of stakeholders and to develop formulaic approaches to prescribing treatments. Considering the need for efficient design and construction processes, the use of a riparian zonation system that relates plant palettes and seed mixes to a hydrologic point of reference (i.e., bankfull) has important practical implications. However, because floodplains include a broad range of hydrologic and geomorphological conditions (i.e., cut banks, benches, slope gradients, etc.) across a site, prescribing treatments based on general terms like “riparian”, “upper riparian,” or “bench”, or Zone 1-4, can be misleading, lead to a reduction in the extents of revegetation efforts, and/or result in locating plant materials where they have an increased risk of failure. This talk will present an approach to defining riparian restoration hydroseres based on design and construction experience of over 20 stream projects in the Southern Rocky Mountains. We will explore methods to designing and communicating plant palettes and seed mixes for various hydroseres is a formulaic way, share key technical tips, and provide case studies.