Gallery Forest or Herbaceous Wetland? The Need for Multi‐Target Perspectives in Riparian Restoration Planning

Abstract

Much riparian restoration focuses on establishment of gallery forests, with relatively limited effort to restore herbaceous wetlands as key components of riparian landscape mosaics. Multiple reasons for this include inherent cultural or esthetic preferences, greater availability of scientific knowledge to support riparian forest restoration, and choices of ecological indicators commonly used for monitoring and assessment. Yet riparian herbaceous wetlands have declined dramatically as a result of river regulation and agricultural development, leading to losses of important habitats and ecosystem services that differ from those provided by gallery forests. As an alternative to a single-minded focus on tree establishment, we advocate restoration of diverse and dynamic habitat mosaics in the context of natural variability of flow and sediment regimes. Landscape context should inform active restoration activities at the local scale, such that riparian forests are not planted in ecologically inappropriate sites. Models are needed to match life history requirements of particular wetland herbaceous plant species with details of flow and sediment transport regimes. We emphasize the importance of herbaceous wetlands as a critical and often overlooked component of riparian ecosystems, and the need for both passive and active restoration of fluvial marshes, sloughs, wet meadows, alkali meadows, off-channel ephemeral ponds, and other critical floodplain communities associated with herbaceous plant dominance.

Novel water sources restore plant and animal communities along an urban river

“…Weisberg et al (2013) note that riparian herbaceous wetlands have declined dramatically in the desert Southwest and have advocated for restoration of diverse and dynamic mosaics, including marshlands, as an alternative to a single-minded focus on tree establishment. One major conclusion is that passive urban discharge along arid urban streams can provide the hydrologic conditions needed for establishing critical wetland and riparian habitat without other types of intervention or management.…”

Incorporating climate change projections into riparian restoration planning and design

“…In some cases, riparian revegetation may be accomplished by creating suitable hydrologic and geomorphic conditions and allowing natural establishment from dispersing seeds and seed banks (Kauffman et al, 1997;Hough-Snee et al, 2013;Meli et al, 2013). Planting is usually implemented at the site scale and is only a temporary solution to problems with unsuitable conditions for natural establishment (Weisberg et al, 2013) but can be a longerterm solution to problems with lack of propagules. Ruwanza et al, 2013).…”

The Rapid Riparian Revegetation Approach

“…Elements described in this paper range from site assessment to planting and include observed limiting factors to riparian restoration success, as well as strategies devised to help address them (Table 1). While the focus of this paper is the restoration and enhancement of degraded riparian forests, we acknowledge the critical importance of non-woody plant dominated riparian plant communities, including fluvial marshes, sloughs, wet meadows, alkali meadows and off-channel ephemeral ponds (Weisberg et al 2012), and do not intend to imply that riparian forests are appropriate or desired in all contexts.…”