Many animal species move soil to search for subterranean resources, build shelter or nest underground, modifying biotic and abiotic habitat characteristics and influencing ecosystem processes from the local to the landscape scale level. This action, of biological reworking of soils and sediments, is referred to as bioturbation. Bioturbation activities carried out by mammals have been recognized as an example of ecosystem engineering throughout the world, however, little attention has been given to the current species conservation status. The aim of this study was to review the main role of ecosystem engineering by world’s bioturbator mammals, examine their conservation status, present research information gaps, as well as to draw attention to the threats these animals may be experiencing.
Based on the information provided by the International Union for Conservation of Nature (IUCN) Red List website, we searched the available data of 3,932 land-dwelling mammals. For each species, we collected the conservation status, continent and country of occurrence, predominant habitat and major threats. Then, to determine the bioturbation capacity of each species, we looked into books and online databases to classify them in the following categories: 1) occasional digger, 2) forager, 3) semi-fossorial and 4) strictly fossorial.
Results/Conclusions
Of the total mammals assessed, 567 species were classified as occasional diggers, 137 as foragers, 691 as semi-fossorials and 97 as strictly fossorials, representing 20 orders and 77 families. Temperate shrublands and subtropical and tropical dry shrublands were the ecoregions with the greatest diversity of mammals. We found that 20% of species are listed as threatened and 28 were already extinct. Asia has the largest number of bioturbator mammals (n=467) and the highest number of threatened species (n=90), followed by Africa (n=63). Oceania has the biggest number of extinctions (n=16) and most species classified as Data Deficient are found in Latin America (n=40). Activities related to agricultural expansion, consumptive use of wild biological resources and issues with invasive species are the main threats. Given the ecological role bioturbator mammals perform in the ecosystem functioning, it is essential to consider their conservation status in order to direct safeguard actions. Many of these threatened species are poorly studied and little is known about their basic ecology. The loss of bioturbator mammals can negatively affect biodiversity, through reducing available resources to microscopic and macroscopic organisms besides affecting ecological processes involving vegetation, nutrient cycling and fire regimes, severely compromising the environmental health.