Dados do Trabalho

TÍTULO

A WORLD REVIEW OF ECOSYSTEM ENGINEERING BY DIGGING MAMMALS

Resumo

The action of biological reworking of soils and sediments is referred as bioturbation. Several species of mammals move soil to search for subterranean food, build shelter or nest underground, modifying biotic and abiotic habitat characteristics and influencing ecosystem processes from the local to the landscape scale level. Diggings 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 preservation situation of these animals. The aim of this study was to examine the status of the world’s digging mammals and present the research information gaps, as well as to draw attention to the threats these animals may be experiencing. Using the International Union for Conservation of Nature (IUCN) Red List website, we searched the available species data to determine the digging capacity of the terrestrial mammals. We only considered species that 1) forages to find subterranean food, 2) creates burrows or warrens and often live underground or 3) are strictly fossorial. From each species we collected their conservation status, continent, country, habitat, threats and body mass. Of the total 2,000 mammals assessed, 92 species were classified in the first group, 348 in the second group, and 73 in the third group, representing 15 orders and 44 families. Temperate grassland, temperate shrubland and temperate forest were the ecoregions with greatest diversity of mammals. We found that 30% of species are listed as threatened (including 10 extinct and 22 critically endangered). America is the continent with the largest number of digging mammals (n = 228) and the highest number of threatened species (n = 51), followed by Asia (n = 34) and Oceania (n = 19), which also shows the biggest number of extinct species (n = 6). In addition, most species classified as Data Deficient are found in the American continent, particularly in South America (n = 31). Asia has species with largest body size and the most threatened species (≥100 kg), while in Oceania, in contrast, smaller body sized mammals (≤40 kg) are the most threatened. Activities related to farming as a result of agricultural expansion and intensification, and the consumptive use of wild biological resources were the main threats for the three groups of digging mammals. Many threatened species are poorly studied and little is known about their basic ecology. Thus, considering the current rates of defaunation worldwide and the potential role these animals perform in the ecosystem functioning, it is essential to consider their conservation status in order to direct safeguard actions. The loss of digging mammals can negatively impact biodiversity, through reducing available resources to microscopic and macroscopic organisms, and affecting important soil processes as the nutrient cycling.

Palavras-chave

bioturbation, soil disturbance, ecosystem engineers