Freshwater and limno-terrestrial meiofauna of the Massane Forest Reserve in the Eastern French Pyrenees

Abstract

We report the results of a faunistic survey focused on freshwater and limno-terrestrial meiofauna to improve biodiversity knowledge in a protected area in the Eastern part of the French Pyrénées: the Massane Forest Reserve (336 ha). The survey provided 1187 occurrence records from 315 taxa (most resolved at species level), uploaded as a shared online dataset and made freely available in the Global Biodiversity Information Facility (GBIF). The highest number of occurrences and distinguishable species belong to Nematoda (775 occurrences, 172 taxa), followed by Rotifera (219 occurrences, 67 taxa), Platyhelminthes (85 occurrences, 32 taxa), Tardigrada (69 occurrences, 25 taxa), and Gastrotricha (39 occurrences, 19 taxa). A diversity of meiofaunal organisms was found, in large numbers, in all the screened samples: from stream biofilms and sediments to forest floor soils, mosses, and litter, to a broad range of tree-related micro-habitats associated with beech epixylic mosses and lichens, tree cavities, woodpecker breeding holes, bark pockets and fruiting bodies of saproxylic fungi. This survey makes the Massane forest one of the few protected areas of the world with an all-taxa biodiversity inventory including meiofaunal groups, which could serve as a standard to further consider those cryptic groups of tiny animals in forest conservation efforts.

An adapted typology of tree-related microhabitats including tropical forests

“…In forests, examples of such indicators are stand structure, tree species composition, tree age, diameter distribution, tree regeneration, and deadwood amount and diversity (Larrieu et al, 2018; Larsson et al, 2001). A more recent approach has emerged from the concept of tree-related microhabitats (TreMs), based on the observation that trees provide important microhabitats for a wide range of organisms, including insects, vertebrates, arachnids, Diplopoda, collemboles, gastropods, fungi, lichens, bryophytes, vascular plants, nematodes, rotifers and tardigrades (Bütler et al, 2020; Larrieu et al, 2018; Majdi et al, 2024; Martin et al, 2022; Müller et al, 2014; Schauer et al, 2018; Winter and Möller, 2008). TreMs are morphological singularities found on living or standing dead trees and form essential substrates or microhabitats for thousands of species.…”