Recovery of plant communities after ecological restoration of forestry‐drained peatlands

Abstract

Ecological restoration is expected to reverse the loss of biodiversity and ecosystem services. Due to the low number of well‐replicated field studies, the extent to which restoration recovers plant communities, and the factors underlying possible shortcomings, are not well understood even in medium term. We compared the plant community composition of 38 sites comprising pristine, forestry‐drained, and 5 or 10 years ago restored peatlands in southern Finland, with special interest in understanding spatial variation within studied sites, as well as the development of the numbers and the abundances of target species. Our results indicated a recovery of community composition 5–10 years after restoration, but there was significant heterogeneity in recovery. Plant communities farthest away from ditches were very similar to their pristine reference already 10 years after restoration. In contrast, communities in the ditches were as far from the target as the drained communities. The recovery appears to be characterized by a decline in the number and abundance of species typical to degraded conditions, and increase in the abundance of characteristic peatland species. However, we found no increase above the drained state in the number of characteristic peatland species. Our results suggest that there is a risk of drawing premature conclusions on the efficiency of ecological restoration with the current practice of short‐term monitoring. Our results also illustrate fine‐scale within‐site spatial variability in the degradation and recovery of the plant communities that should be considered when evaluating the success of restoration. Overall, we find the heterogeneous outcome of restoration observed here promising. However, low recovery in the number of characteristic species demonstrates the importance of prioritizing restoration sites, and addressing the uncertainty of recovery when setting restoration targets. It appears that it is easier to eradicate unwanted species than regain characteristic species by restoration.

Rapid recovery of invertebrate communities after ecological restoration of boreal mires

“…However, this hypothesis may be unrealistic because the restoration of habitat features and plant communities do not necessarily guarantee the recolonization of other taxa (Zanden et al ). Moreover, biodiversity generally remains lower (Benayas et al ) and the community composition altered (Haapalehto et al , , in review; see also Elo et al , in press) in disturbed and restored versus intact ecosystems, demonstrating that efforts to create favorable conditions do not necessarily bring back species. It might also mean that key abiotic and biotic conditions in the restoration process have not been identified correctly or that the abiotic environment has not yet been restored.…”

“…Although it is assumed that if the physical conditions of an ecosystem are recreated, the biotic system will gain features of the undisturbed habitats simply by natural succession (Suding et al ), the generality of this assumption needs further scrutiny (Palmer et al ; Elo et al , in press). For example, the restoration of wetlands may follow various trajectories in terms of changes in species abundances, community structure, and ecosystem functions, and appears to be habitat specific (Zedler ; Menninger & Palmer ; Haapalehto et al , in review). Furthermore, the relationship between habitat restoration, changes in various environmental variables, and changes in biodiversity remain relatively poorly understood.…”

“…In contrast, microinvertebrates (van Duinen et al ), Diptera (Taillefer & Wheeler ), and Odonata (Elo et al , in press) seem to benefit from recovery by the rewetting of damaged peatlands. Thus, as different species, including endangered species and communities, potentially respond differently to restoration practices (van Duinen et al ; Babin‐Fenske & Anand ), it is essential to have a mechanistic understanding of the processes involved in recovery (Elo et al , in press; Haapalehto et al , in review).…”

Quantifying the relationship between soil seed bank and plant community assemblage in sites harboring the threatened Ivesia webberi in the western Great Basin Desert

“…An assessment of the relationship between the above‐ground plant community and the soil seed bank is critical to understanding the ecological resistance and resilience of an ecosystem and post‐disturbance successional pattern (Korb et al, 2005; Ma et al, 2019; Mndela et al, 2020). Such an understanding is needed to support successful restoration efforts, and reverse biodiversity loss (Ma et al, 2010; Haapalehto et al, 2017). However, the majority of studies that investigated the association between the above‐ground plant communities and the soil seed bank reported low floristic similarity, and many soil seed banks are dominated by native and exotic annual ruderal and early‐successional species (Peco et al, 1998; Decocq et al, 2004; Hopfensperger, 2007; Bossuyt and Honnay, 2008).…”

Effects of habitat restoration on peatland bird communities

“…The natural pristine state of the peatlands, together with hydrology and carbon storing capacity, recovers faster through restoration (Jauhiainen et al 2002; Vasander et al 2003; Haapalehto et al 2014). However, recovery may be incomplete and in many aspects the restored peatlands may differ greatly from their pristine state (Moreno‐Mateos et al 2012; Haapalehto et al 2017). Indeed, a full recovery of peatland biota may take several decades (Gorham & Rochefort 2003; Moreno‐Mateos et al 2012), even though a significant number of typical peatland species can recover in 3–5 years (Gorham & Rochefort 2003; Noreika et al 2015).…”