Identifying Preferential Associates to Initiate Restoration Plantings

Abstract

Ecological restoration typically aims to re-establish dominant plant species and their native associates, despite the lack of guidance on which associates to introduce initially. Analysis of naturally occurring plant communities can provide criteria to shorten the list of species that are associated with dominants, in order to focus revegetation efforts on species likely to establish. Using the example of sedge meadows, we evaluated wetland vegetation data from Laurentian Great Lakes wetlands to identify "preferential associates," that is, species that co-occur more frequently than expected based on their overall abundance. A total of 176 taxa occurred within the two hundred and thirty-nine 1 × 1 m 2 plots in 48 wetlands that contained Carex stricta, a widespread tussock-forming sedge. Of 58 species that co-occurred with C. stricta where it was dominant (≥50% plot cover), we identified 26 associates using Bray-Curtis similarities and we determined that 12 of the 26 were preferential using an electivity index. The electivity index identified preferential associates even when they occurred infrequently or had low mean cover per plot. We provide guidance on how to initiate restoration with preferential associates.

Effectiveness of a Constructed Wetland in Reducing Phosphorus Inflow Loads from an Agricultural Catchment Area

“…The constructed wetland accumulated 0.4 g P m -2 year -1 . A similar accumulation of phosphorus was shown by Johnston [4], whereas a study by Wang et al [24] into the accumulation of phosphorus in deposits supplied with sewage showed phosphorus to accumulate at a rate of 30 g P m -2 year -1 .…”

“…This greatly reduces the effects of the sewage treatment plant construction program in rural areas. In order to improve sewage management and to protect waters from a harmful excess of biogenic elements, the various methods employed should include the natural biological, physical and chemical processes that take place in natural and constructed wetlands, which very effectively stimulate biological treatment of water [3][4][5][6].…”

Local disturbance by muskrat, an ecosystem engineer, enhances plant diversity in regionally‐altered wetlands

“…were typically found at the base of cattail stems or growing out from the house, while the wetland obligate, Bidens spp., was also largely found growing on cattail mats (Z. X. Kua, personal communication ). Among the species identified to occur more in muskrat‐disturbed transects, three taxa (i.e., Lysimachia spp., Scutellaria spp., and Cicuta bulbifera ) were plants associated with sedge tussock mounds (Johnston and Zedler 2012). In this case, muskrat house structures may create similar physical structures which allow these tussock‐associated plants to occur more frequently around muskrat houses.…”

“…Moreover, the higher abundance of Lemna minor around muskrat‐disturbed areas may be associated with the habitat type associated with muskrat activity. The lesser presence of C. lacustris around muskrat houses, alongside P. arundinacea, was also identified as wetland plants associated with tussock mounds (Johnston and Zedler 2012). However, inferences made based on these observed differences remain speculative and will require further studies and observations to help properly understand these phenomena.…”

Phenology of Carex stricta: It pays to be tall!

“…Carex stricta supports biodiversity, including several associates recommended for introduction after the C. stricta matrix is well established in restoration sites (Johnston and Zedler 2012). Tussocks add surface area (40% more with 15-25 cm-tall tussocks; Werner and Zedler 2002), provide topographic heterogeneity, and grow early in spring, allowing temporal segregation (Peach and Zedler 2006;this study).…”