Terrestrial invertebrates as bioindicators in restoration ecology: A global bibliometric survey

Biodiversity promotion activities, such as ecological restoration, are recognized as instruments to arrest and mitigate the diminishing health of ecosystems. The restoration of fauna is a fundamental component of this process but, despite this, there are few studies that compile and discuss the knowledge produced on this topic. Hence, by seeking a general understanding of what we currently know about terrestrial invertebrates as bioindicators in restored ecosystems, the present work sought to organize knowledge in such a way as to indicate gaps and opportunities for both researchers and restorers. To this end, we searched for topics associated with restoration ecology in the Web of Science database, identifying which invertebrate groups have been studied in relation to intrinsic characteristics of ecological intervention, including type of biome, type of disturbance, restoration technique, age, project size, and indices used. We found 154 studies published between 1995 and 2018: 93.5% of which were from 2002 onwards. We detected a growing number of studies and a tendency to evaluate functional groups. Moreover, there was a high concentration of studies within a few taxonomic groups, notably Hymenoptera (Formicidae), Coleoptera, and Lepidoptera. Many of the restoration scenarios are poorly studied, for example, in temperate coniferous forests or taiga biomes, previous disturbances caused by pollution or urbanization, under certain restoration techniques such as brushwood transposition, and investigations in large or old areas. There was also a paucity of information concerning community or population-level measures of restoration success, such as the structure of communities, biomass, and dominance. We discuss some consequences of these knowledge gaps. Finally, we indicate which taxonomic groups have been evaluated in relation to each restoration characteristic considered, resulting in guidance for those wishing to engage in research and monitoring of such organisms during the restoration process.

Automated summary

This study analyzed research on terrestrial invertebrates as bioindicators in restored ecosystems from 1995 to 2018, finding a concentration of studies within certain taxonomic groups and a lack of research in some restoration scenarios and techniques. The number of relevant studies has been increasing over time, but there is still a scarcity of information on community or population-level measures of restoration success.