Restoration for variability: emergence of the habitat diversity paradigm in terrestrial ecosystem restoration

Abstract

Ecosystem restoration implies focusing on multiple trophic levels and ecosystem functioning, yet higher trophic levels, that is, animals, are less frequently targeted by restoration than plants. Habitat diversity, the spatial heterogeneity between and within habitat patches in a landscape, is a well-known driver of species diversity, and offers possible ways to increase species diversity at multiple trophic levels. We argue that habitat diversity is central in whole-ecosystem restoration as we review its importance, provide a practical definition for its components, and propose ways to target it in restoration. Restoration targeting habitat diversity is used commonly in aquatic ecosystems, mostly to increase the physical diversity of habitats, meant to provide more niches available to a higher number of animal species. To facilitate the uptake of habitat diversity in terrestrial ecosystem restoration, we distinguish between compositional and structural habitat diversity, because different animal groups will respond to different aspects of habitat diversity. We also propose four methods to increase habitat diversity: varying the starting conditions to obtain divergent successional pathways, emulating natural disturbances, establishing keystone structures, and applying ecosystem engineer species. We provide two case studies to illustrate how these components and methods can be incorporated in restoration. We conclude that targeting habitat diversity is a promising way to restore habitats for a multitude of species of animals and plants, and that it should become mainstream in restoration ecology and practice. We encourage the restoration community to consider compositional and structural habitat diversity and to specifically target habitat diversity in ecosystem restoration.

Reptile responses to vegetation structure in a grassland restored for an endangered snake

“…This information is central in habitat restorations, where the target state should be defined based on the habitat preference of each target species. Our study also shows that habitat restorations should target the vegetation structure that is most likely to benefit all species (Lengyel et al 2020). Restoration of vegetation structure may be achieved in a more economic way compared to vegetation composition or plant species richness, which is usually expensive in case of target state of primary grasslands (cultivating/collecting seeds, producing high-diversity seed mixtures, soil preparation, sowing, etc.…”

“…However, the target state aimed by grassland restoration is often defined based on the desired plant species or vegetation, and higher trophic levels are rarely targeted (Woodcock et al 2008). Consequently, knowledge of the vegetation composition, structure or complexity required for habitat restoration for vertebrate wildlife is rather poor in most cases (Lengyel et al 2016(Lengyel et al , 2020.…”

Restoring Riparian Ecosystems During the UN-Decade on Ecosystem Restoration: A Global Perspective

“…During floods, this information also supports the local administration for preparedness, monitoring, mitigation, and flood risk assessment (Dang and Kumar, 2017). During the final stage of eco-restoration, the monitoring phase, geoinformatics supports assessing the improvement of the niche of various life forms (Lengyel et al 2020;Hortobágyi et al 2018) and the health regaining rate of various ecosystems along the riparian corridor (Golet et al 2008;Hausner et al 2018).…”

“…Ecosystems support various life forms on earth. Down the ages, human activities have impaired ecosystems around the world (Dybala et al 2018;Lewis et al 2019;Álvarez-Yépiz 2020) The acreage of pristine ecosystems is decreasing across the planet and is on the verge of degradation (Lengyel et al 2020). Restoration of ecosystems is required for the survival of all organisms (Vollmer et al 2015;Daigneault et al 2017;Mohan et al 2020).…”

Efforts at the beginning pay off: sowing grasses and forbs simultaneously supports restoration of species-rich grasslands and improves weed control in ex-arable land

“…Halting their degradation, decreasing their fragmentation and increasing their area, as well as conserving their diversity are as important as afforestation principles [8,9] . By restoring species-rich grasslands not only plant diversity can be increased, but also habitat heterogeneity, which in turn facilitates restoration of other life forms [10] . These targets can be achieved both by restoration of degraded species-rich grassland ecosystems [11] and by grassland recreation in abandoned croplands [12,13] .…”