If we build – they mostly come: partial functional recovery but persistent compositional differences in wetland beetle community restoration

Abstract

There is growing evidence of restoration success for wetland plant communities. However, little research has been done on the associated invertebrate community. We test whether restoring plant communities after peat extraction is sufficient for restoring the taxonomic and functional composition of beetle communities. We monitored taxonomic and trait-based community metrics for beetle assemblages on restoration islands that were up to 13 years old and compared these with the adjacent "target" undisturbed peat bog. Recovery of beetle abundance, species richness, and trophic structure on the islands was remarkably rapid (i.e. within a decade) and converged on that of the undisturbed peat bog within 13 years after restoration commenced. In contrast, small, native, and poor-dispersing taxa were persistently less abundant on the islands than in the undisturbed peat bog, causing persistent differences in species composition, even on the oldest islands. These poor-dispersers probably need assistance to reach the islands and possibly ongoing intervention to allow them to survive there. Our findings emphasize the potential for functional trait analysis to reveal barriers to full restoration of insect community composition.

Restoration of Sphagnum and restiad peatlands in Australia and New Zealand reveals similar approaches

“…Having an adequate seed source for peatland species was also a key requirement, and in areas where the original vegetation had been destroyed or badly damaged (e.g. by fire or peat mining), a patch dynamic approach to restoration ( Sphagnum transplants, vegetated islands, shadecloth‐enhanced vegetated strips) was proving successful and cost‐effective (Watts et al ; Whinam et al ; Watts & Mason ). Reassembly of peatland flora and fauna, and reinstatement of hydrological regimes and ecosystem processes to a restored state (resembling pre‐European conditions in the Australian Alps and pre‐mining conditions at Torehape), however, will be a complex undertaking lasting several decades, even in the absence of further major disturbances (Watts et al ; Good et al ).…”

“…However, the use of low‐cost “raised treatment” peat island restoration technique (as described above) was still effective in starting beetle community reassembly. More recently, Watts and Mason () returned to Torehape mine and found that the recovery of most ground‐dwelling beetles on the peat islands was relatively rapid and converging on that of the undisturbed peatland within 13 years after establishment. In addition, the age of restoration and the related changes in vegetation structure, including canopy density and height, and vegetation cover, strongly influenced beetle species composition.…”

“…At Torehape mine, restoration experiments using combinations of water table, nutrients, and bog species, characteristic of both early and late successional phases, were trialed in 1998 to develop a suitable cost-effective approach to whole-mine site restoration (Schipper et al 2002). This program is ongoing and has resulted in a range of research projects including restoration of invertebrate and vegetation communities (Watts & Didham 2006a, 2006bWatts et al 2008a) and ecosystem processes (Watts et al 2008b;Clarkson et al 2009;Watts & Mason 2015). In addition, it has expanded to the "reconstruction" of three new populations of Sporadanthus-Empodisma robustum at sites where the bog type originally occurred ( Fig.…”

Untitled

“…1e), functional recovery was partly a consequence of the redistribution of biomass among different functional types (Dolbeth et al 2013). Similarly rapid recovery of functional diversity has been observed in other invertebrate communities, such as beetles in restored wetlands (Watts and Mason 2015). These studies, along with ours, suggest that functional traits can be a powerful tool for assessing the response and subsequent recovery of communities to disturbance (Mouillot, Graham, et al 2013).…”

Untitled

“…1e), functional recovery was partly a consequence of the 474 redistribution of biomass among different functional types (Dolbeth et al 2013). Similarly rapid 475 recovery of functional diversity has been observed in other invertebrate communities, such as 476 beetles in restored wetlands (Watts and Mason 2015). These studies, along with ours, suggest that 477 functional traits can be a powerful tool for assessing the response and subsequent recovery of 478 communities to disturbance (Mouillot, Graham, et al 2013).…”