Ecosystem roles and conservation status of bioturbator mammals
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Oct 26, 2021 version files 171.84 KB
Abstract
The action of biological reworking of soils is referred to as bioturbation, and many species of mammals globally have an important role in soil disturbance, modifying ecosystem characteristics.
We examined global patterns in the distribution, conservation status, and threats to the world’s bioturbator mammals and illustrated the relevant roles these species play in ecosystem engineering related to soil processes and services. We searched the data available on 3932 non‐flying land‐dwelling mammals included in the International Union for Conservation of Nature’s (IUCN) Red List.
Using existing literature and online databases, we determined that 869 (22%) of the non‐flying land‐dwelling mammals accessed can be considered as bioturbators in three distinct groups: foragers (n = 123), semi‐fossorial species (n = 652), and strictly fossorial species (n = 94). Of the world’s bioturbator mammal species, 16% are threatened, 2% are already Extinct, and 8% are classified as Data Deficient. Foragers have the highest percentage of threatened (35%) and Extinct (5%) species, while strictly fossorial species have the highest percentage of Data Deficient species (12%). Although the majority of bioturbator mammal species are found in Asia (32%), Oceania is the continent with the highest percentage of threatened (27%) and Extinct (11%) bioturbator species, while Central and South America have the highest percentage of species classified as Data Deficient (24%). The threats experienced by the greatest number of bioturbator mammal species are activities related to agriculture and aquaculture (29%), and biological resource use (22%).
Soil bioturbation can improve ecosystem health by reducing soil compaction, increasing nutrient cycling, soil moisture, microbe diversity, plant recruitment, and carbon storage. The loss of bioturbator mammals could trigger cascading effects throughout the ecosystems they inhabit. A better understanding of their conservation status is important so that effective conservation measures can be developed.
Methods
From the available data on the 5900 species of mammals present on the International Union for Conservation of Nature’s (IUCN) Red List, we searched for land-dwelling non-volant mammal species in order to identify how many of these species perform bioturbator activities. We based our search only on the species on the IUCN Red List, since this is the most comprehensive inventory of the global conservation status of biological species. The list of species is updated regularly, but we only included information about species that were available from October 2018 to April 2020, when searches were conducted. We did not include 1968 species, due to their flying or marine habits, but we did include freshwater-area associated species and species that are mostly arboreal but also spend time on the ground, for example, members of the Cricetidae and Sciuridae family. This meant that 3932 species were assessed for bioturbation activities. We used books (Nowak & Walker 1999, Wilson & Mittermeier 2009) and online databases (Google Scholar, Microsoft Academic and WorldWideScience, Web of Science, ScienceDirect, Scopus, JSTOR, and IUCN Red List website) in order to find reliable scientific publications from the last 30 years, in both English and Spanish, when available. When using online databases, we searched one species at a time, typing the species name followed by key terms ‘dig’ and/or ‘burrow’, to determine whether the species could be considered a bioturbator mammal. Although many species occasionally dig, here we consider a bioturbator mammal to be a species that is either an obligate digger or performs regular digging activities to meet foraging, nesting, or shelter requirements. When a species fitted in more than one group, we used the group with which the bioturbation activity of the species was most strongly associated.