Management Recommendations for Washington's Priority Habitats and Species: Riparian Pollinators

Riparian ecosystems are global hotspots of biological diversity, providing habitat for many species of fish and wildlife (Kauffman et al. 2001). Riparian areas in the Pacific Northwest are no exception. Situated at the interface between terrestrial and aquatic environments, riparian areas provide the moisture necessary to sustain diverse ecological communities (Kauffman et al. 2001). These ecosystems generally support a high diversity and richness of native vascular plants compared to surrounding areas with less available moisture (Raedeke 1989, Gregory et al. 1991, Décamps and Tabacchi 1993, Naiman et al. 1993). These rich plant communities are also often varied in their vegetative structure (Gregory et al. 1991), which creates niches for numerous species of fish and wildlife, including pollinators (Kauffman et al. 2001, Cole et al. 2015). The abundance and diversity of plants, and especially flowering plants, supports pollinators by providing them with habitat for foraging, nesting, and overwintering (Roof et al. 2018).

Riparian ecosystems can provide important refuge for wildlife during periods of intense heat and drought (Seavy et al. 2009). The proximity to open water in riparian areas moderates the environmental conditions compared to surrounding landscapes (Kauffman et al. 2001). This often creates microclimates that provide resources and refuge to a variety of species (Seavy et al. 2009). These moderating influences may also result in periods of flowering that differ from the surrounding landscape. This can contribute to increased opportunities for pollinator foraging within a landscape and make riparian areas particularly valuable as habitat. As climate change continues to alter environmental conditions, riparian areas could become important climate-change refugia for invertebrates including pollinators (Seavy et al. 2009, Ramey and Richardson 2017).