Salvaged-Wetland Soil as a Technique to Improve Aquatic Vegetation at Created Wetlands in Wyoming, USA

Abstract

Aquatic plants usually establish following wetland creation from a variety of mechanisms including animal transport, inflows from nearby wetlands, wind dispersal, and seed banks if they are available. However, at created wetlands that are isolated from natural wetlands, aquatic plant communities may not establish even after 10 or more years. One method of improving the establishment of aquatic plants is through the use of salvaged-marsh soils. Using this method, wetland soil from a donor site is collected and spread across the basin of the created wetland. When the proper hydrologic regime is reached at the created site, the seed bank from the donor soil is then present to take advantage of the uncolonized site. Over 1500 wetlands have been created in northeast Wyoming, USA from bentonite mining and most of them have not developed submersed and emergent plant communities due to isolation from plant sources. Our goal was to evaluate the effectiveness of using salvaged-wetland soil as a tool for improving plant growth at created wetlands. Our study took place at 12 newly created wetlands that were isolated from other wetlands by >5 km. Six wetlands were treated as reference wetlands, with no introductions of seeds or propagules. At the other six wetlands we spread %10-15 cm of salvaged soil from a donor wetland during the winter of 1999-2000. To identify the potential plants in donor soil, we collected 10 random samples from the donor wetlands and placed them within wetland microcosms in a greenhouse where they were treated to either moist-soil conditions (water at or just below the soil line) or submersed conditions (water levels maintained at 15-30 cm). Treatment wetlands were evaluated for plant growth during the fall of 2000 and 2001, whereas the greenhouse samples were grown for two growing seasons then harvested. Our results show that using salvaged wetland soil increases: (1) the number of plant species present at a wetland over time, (2) the total vegetation coverage in a treated wetland over time, and (3) the total plant biomass in a treated wetland. The species pool available in the salvaged wetland soil was limited to 10 obligate wetland species, but several of them are considered valuable to waterfowl and other wildlife. Furthermore, salvaged-wetland soil could be useful for ameliorating poor substrate conditions (i.e., bentonite) and improving conditions for the establishment of additional species. One concern with this technique is the introduction of invasive or exotic species that could form monocultures of undesirable plants (e.g., cattail [Typha spp.]); introducing more desirable species during the application of salvaged soil could reduce this probability. We believe incorporating salvaged-wetland soil during basin construction could be used to increase the value and productivity of created wetlands in this region.

Temporary wetland restoration after rice cultivation: is soil transfer required for aquatic plant colonization?

“…Although they are less adapted to the temporary wetland and tend to disappear over time, a certain plasticity of their phenology allowed their presence in the mesocosms and can thus compromise succession and prevent the natural reestablishment of target species. Soil transfer appears to be an appropriate method to accelerate succession towards the desired community and to attempt to bypass some of blocked stages of succession (Collinge and Ray, 2009;McKinstry and Anderson, 2005;Reinartz and Warne, 1993). In using soil transferred from several donor sites, we increase the number of target hydrophyte species at one site compared with a single donor site.…”

“…This dormant reservoir is a powerful mechanism for maintaining species diversity by promoting the coexistence of a greater number of species. In addition, soil transfer allows i) the preservation of biotic interactions by transferring soil microorganisms (Bullock, 1998) which play an important role in structuring plant community (Moora and Zobel, 2009) and in improving substrate conditions (McKinstry and Anderson, 2005) and ii) the potential transfer of zooplankton and macroinvertebrate egg bank. Brady and coauthors (2002) demonstrated that soil transfer leads to a more natural invertebrate community structure, and can be a significant benefit for non-aerial invertebrates, which are not able to disperse alone, such as crustaceans (Cladocera and Triops).…”

“…Several studies have demonstrated dispersal limitation despite the proximity of natural temporary wetlands (Collinge and Ray, 2009;Galatowitsch and Valk, 1996). Moreover, the site to be restored may be isolated from the network of wetlands (McKinstry and Anderson, 2005;Reinartz and Warne, 1993) or may have been submitted to a long cultivation period (Prach et al, 2001), which often limits re-colonization. In such cases, active restoration, including reestablishment of dispersal vectors, is needed to restore plant communities (Bischoff, 2002).…”

Restoration of wetland vegetation using soil seed banks: lessons from a project in Lake Kasumigaura, Japan

“…Several methods for introducing plants to restoration sites have been used, including transplanting, sowing hand-collected or commercially available propagules (Reinartz and Warne 1993;Vé crin et al 2002;Rochefort et al 2003;Bissel et al 2004), transferring freshly mown plant material (Hö lzel and Otte 2003), whole turf translocation (Good et al 1999), and spreading soil that contains wetland-plant seed banks or propagule banks (Stauffer and Brooks 1997;Bruelheide and Flintrop 2000;Vé crin and Muller 2003;Cobbaert et al 2004;McKinstry and Anderson 2005) (hereafter, 'seed bank' implies propagule bank). The use of soil seed banks is thought to be advantageous in conserving and restoring biodiversity because the seed banks of past and present wetlands may be expected to contain a variety of species and genetically diverse individuals (Levin 1990;van der Valk et al 1992).…”

“…Furthermore, the recovery of species that have disappeared from the above-ground vegetation may also occur, depending on the seed characteristics and environmental conditions. Nowadays, the usage of soil seed banks as plant materials is becoming a common revegetation technique in wetland restoration (Vivian- Smith and Handel 1996;Brown and Bedford 1997;Stauffer and Brooks 1997;Bruelheide and Flintrop 2000;Rochefort et al 2003;Vé crin and Muller 2003;Cobbaert et al 2004;McKinstry and Anderson 2005).…”