Ecosystem Birth near Melting Glaciers: A Review on the Pioneer Role of Ground-Dwelling Arthropods

Abstract

As glaciers retreat, their forelands represent “natural laboratories” for the study of primary succession. This review describes how certain arthropods conquer pristine ground and develop food webs before the establishment of vascular plants. Based on soil samples, pitfall traps, fallout and sticky traps, gut content studies, and some unpublished data, we compare early arthropod succession on glacial forelands of northern Europe (Iceland, Norway including Svalbard, and Sweden) and of the Alps (Austria, Italy). While macroarthropod predators like ground beetles (Coleoptera: Carabidae), harvestmen (Arachnida: Opiliones), and spiders (Arachnida: Araneae) have usually been considered as pioneers, assumed to feed on airborne prey, this review explains a different pattern. Here, we highlight that springtails (Collembola), probably feeding on biofilm made up of algae or cyanobacteria, are super-pioneers, even at high altitudes and under arctic conditions. We also point out that macroarthropod predators can use locally available prey, such as springtails or non-biting midges (Diptera: Chironomidae). Pioneer arthropod communities vary under different biogeographical and climatic conditions. Two pioneer food webs, from northern Europe and the Alps, respectively, differed in structure and function. However, certain genera and orders were common to both. Generalists and specialists live together in a pioneer community. Cold-adapted specialists are threatened by glacier melting.

Ecology of the cold-adapted species Nebria germari (Coleoptera: Carabidae): the role of supraglacial stony debris as refugium during the current interglacial period

“…In the last decades, the key biological role of debris-covered glaciers has been recognised. Indeed, this habitat is hosting cold-adapted arthropod species during the current interglacial period (Gobbi et al 2011, Hågvar et al 2020. The Dolomites are particularly sensitive to the effects of climate change because of their relatively low altitude and the small size of their glaciers, which are undergoing a shrinking of surface size and an increase in debris cover that could partially reduce melting rate (Nakawo & Rana 1999).…”

“…Under the current climate change scenario, debris-covered glaciers are assuming a key biological role in high-altitude environments because they can host cold-adapted arthropod and plant species (Caccianiga et al 2011, Gobbi et al 2011, Hågvar et al 2020. In fact, cold-adapted species may react to rising temperatures by finding refugium areas in glacial and periglacial landforms, as suggested for the Alps by Gobbi et al (2011Gobbi et al ( , 2014Gobbi et al ( , 2018.…”

Rock glaciers and related cold rocky landforms: Overlooked climate refugia for mountain biodiversity

“…Globally, mountains are biodiversity hotspots (Rahbek et al, 2019) due to high rates of local endemism driven by a combination of habitat isolation and adaptation to cold conditions (Muhlfeld et al, 2020; Smith & Weston, 1990). Many microbes, plants, and animals in terrestrial and aquatic environments are associated with glaciers and other cold habitats (Gobbi & Lencioni, 2020; Hågvar et al, 2020; Hotaling, Foley, et al, 2019; Lencioni, 2018). Thus, the rapid contemporary warming of mountain ecosystems is projected to threaten cold‐adapted biodiversity worldwide (Brighenti, Tolotti, Bruno, Wharton, et al, 2019; Hågvar et al, 2020; Hotaling et al, 2017, 2020; Millar et al, 2018; Stibal et al, 2020).…”

“…Many microbes, plants, and animals in terrestrial and aquatic environments are associated with glaciers and other cold habitats (Gobbi & Lencioni, 2020;Hågvar et al, 2020;Hotaling, Foley, et al, 2019;Lencioni, 2018). Thus, the rapid contemporary warming of mountain ecosystems is projected to imperil cold-adapted biodiversity worldwide Hågvar et al, 2020;Hotaling et al, 2017;Hotaling, Wimberger, et al, 2020;Millar et al, 2018;Stibal et al, 2020).…”

Desoria calderonis sp. nov., a new species of alpine cryophilic springtail (Collembola: Isotomidae) from the Apennines (Italy), with phylogenetic and ecological considerations

“…These organisms appear to be differentiated among isolated glacial areas (Deharveng 1975;Lauga-Reyrel & Lauga 1995). By comparing different European glacier forelands, Hågvar et al (2020) observed how the species belonging to this group, and to a few other pioneer genera, are important not only as components of supraglacial communities (see also Gobbi et al 2021), but also as early colonisers of recently-deglaciated terrains. High diversity of cryophilic Isotomidae was observed in southern Alaska and in the Canadian Rocky Mountains in North America (Fjellberg 2010).…”