Does Facilitation of Faunal Recruitment Benefit Ecosystem Restoration? An Experimental Study of Invertebrate Assemblages in Wetland Mesocosms

Abstract

We used wetland mesocosms (1) to experimentally assess whether inoculating a restored wetland site with vegetation/sediment plugs from a natural wetland would alter the development of invertebrate communities relative to unaided controls and (2) to determine if stocking of a poor invertebrate colonizer could further modify community development beyond that due to simple inoculation. After filling mesocosms with soil from a drained and cultivated former wetland and restoring comparable hydrology, mesocosms were randomly assigned to one of three treatments: control (a reference for unaided community develop-ment), inoculated (received three vegetation/sediment cores from a natural wetland), and stocked ϩ inoculated (received three cores and were stocked with a poorly dispersing invertebrate group-gastropods). All mesocosms were placed 100 m from a natural wetland and allowed to colonize for 82 days. Facilitation of invertebrate colonization led to communities in inoculated and stocked ϩ inoculated treatments that contrasted strongly with those in the unaided control treatment. Control mesocosms had the highest taxa richness but the lowest diversity due to high densities and dominance of Tanytarsini (Diptera: Chironomidae). Community structure in inoculated and stocked ϩ inoculated mesocosms was more similar to that of a nearby natural wetland, with abundance more evenly distributed among taxa, leading to diversity that was higher than in the control treatment. Inoculated and stocked ϩ inoculated communities were dominated by non-aerial invertebrates, whereas control mesocosms were dominated by aerial invertebrates. These results suggest that facilitation of invertebrate recruitment does indeed alter invertebrate community development and that facilitation may lead to a more natural community structure in less time under conditions simulating wetland restoration.

Effect of restoration on zooplankton community in a permanent interdunal pond

“…Some studies conducted in invertebrates and vegetation have suggested the importance of this viable present egg bank to facilitate colonization after pond restoration (Brouwer and Roelofs, 2001;Brady et al, 2002;Jenkins and Boulton, 2007).…”

Macroinvertebrate assemblages and biodiversity levels: ecological role of constructed wetlands and artificial ponds in a natural park

“…Macroinvertebrates are directly affected by the physical and chemical integrity of the surrounding environment, including water quality (EPA, 2002). They are known to influence the rates of nutrient cycling and decomposition, to have a central position in the wetland food webs and to integrate environmental impacts and changes through time (Scatolini and Zedler, 1996;Sharitz and Batzer, 1999;Brady et al, 2002;Stanczak and Keiper, 2004). Therefore, they are potentially useful as indicators of restoration success (Campbell et al, 2002).…”

Influence of flooding and vegetation patterns on aquatic beetle diversity in a constructed wetland complex

“…Many aquatic beetles prefer breeding in waters with dense aquatic vegetation, as it provides food and cover for larvae and imagos (Hebauer 1986, De Szalay andResh 2000), as well as for other macroinvertebrate taxa (Nicolet et al 2004). The experiments of Brady et al (2002) confirm this hypothesis; they found similarities in invertebrate community structures between inoculated and natural water bodies and significant differences between inoculated and control areas without vegetation. However, the abundances of some groups, including Coleoptera, were much lower in the vegetated mesocosms of that investigation.…”

“…To facilitate the establishment of plant species to achieve a more natural habitat, it is a common procedure to inoculate desired plant species (Brady et al 2002). Breeding habits of aquatic beetles seem to explain the differences between the planted and unplanted SF wetlands.…”

“…Brady et al (2002) investigated their wetland mesocosms 82 days after inoculation, whereas we took samples three years after plantings. The timing of the experiment of Brady et al (2002) might have precluded colonization by aerial invertebrate taxa that have fall or spring emergence. In contrast, we studied the restoration area through multiple vegetation periods.…”