Ecosystem Birth near Melting Glaciers: A Review on the Pioneer Role of Ground-Dwelling Arthropods
Faculty of Environmental Sciences and Natural Resource Management, Norwegian University of Life Sciences, 1433 Aas, Norway
MUSE-Museo delle Scienze, Corso del Lavoro e della Scienza, 3, I-38122 Trento, Italy
Department of Ecology, University Innsbruck, Technikerstrasse 25, A-6020 Innsbruck, Austria
Department of Biology, Lund University, Sölvegatan 37, S-223 62 Lund, Sweden
Department of Biosciences, Università degli Studi di Milano, Via Giovanni Celoria 26, 20133 Milano, Italy
Museo Civico di Scienze Naturali “E. Caffi” di Bergamo, Piazza Cittadella 10, I-24129 Bergamo, Italy
Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
Science and Technology Facilities Council, Polaris House, Swindon SN2 1FL, UK
Author to whom correspondence should be addressed.
Received: 15 August 2020 / Revised: 14 September 2020 / Accepted: 16 September 2020 / Published: 19 September 2020
Due to climate change, glaciers are retreating. On newly deglaciated ground, ecosystems gradually evolve through the process of primary succession. This gives scientists a unique opportunity to study how a new ecosystem is born. During the first few years, before plants establish, the barren ground of sand, silt, and stones close to the ice edge is conquered by a rich variety of insects, spiders, and other small animals. Many of these are predators and their prey are either transported by air or produced in situ. The real pioneers are, however, wingless springtails that graze on biofilm containing algae or cyanobacteria. Studies of two pioneer food webs showed differences in structure and function. In the one case, beetles, spiders, and harvestmen exhibit preferences for locally produced springtails, while predators in the other example relied mainly upon midges hatching from young ponds. Pioneer communities contain a mixture of generalists and specialists. Species composition vary under different climatic and geographical conditions, depending on the available candidate species in the surrounding areas. This study illustrates flexibility in the early phase of primary succession. Certain cold loving beetles, spiders, and springtails may become extinct if glaciers disappear completely.