**2. Glacial biodiversity: glacial and periglacial landforms as habitat for cryophilous species**

At first glance, the ground surrounding the glacier front, its surface and the streams originated by the melting glaciers seems to be too extreme to host any life forms. Conversely, there are many organisms that permanently colonize the cryosphere, from bacteria to vertebrates, the so-called glacial biodiversity [7].

From the quantitative point of view, the glacial biodiversity is mainly formed by little (less of 5 cm) or microscopic organisms linked to aquatic, semiaquatic, wet or terrestrial (mainly bare and rocky grounds) habitats.

The surface of glaciers is colonized by bacteria and algae [8, 9] and mosses, hosting in turn water bears (Tardigrade), roundworms (Nematoda) and potworms (Enchytraeidae) [10]. They can live also directly on the surface of the ice, in cryoconite holes and rivulets on ice. In addition, on the glaciers, it is possible to observe wandering several spiders (Araneae) during the day as well as some ground beetles (Coleoptera: Carabidae) during the night searching for preys. Many other invertebrates, mostly connected with aquatic/wet environments, such as springtails (Collembola), stoneflies (Plecoptera) and non-biting midges (Diptera: Chironomidae), can live directly on the surface of the ice [11]. Moreover, supraglacial cryoconite holes can be considered biodiversity hotspots for invertebrates such as Copepoda, worms (Annelida), water bears, roundworms and wheel animals (Rotifera) [11, 12].

Most of the invertebrates living on the glaciers can be found also along recently deglaciated terrains and in the uppermost reach of glacial streams. Thus, the glacial biodiversity living at the edge with the glacier front arrives from two different sinks: falling down from the glacier surface during the melting phases and shifting up along the glacier forelands, transported airborne or by walking. Typically, springtails and moss mites (Oribatida) are the first colonizers of recently deglaciated areas because they are easily transported by the wind, thanks to their lightweight. Some sheet weaver spiders (Linyphiidae) are as well colonizers transported by wind [13]. Thus, recently deglaciated terrains act as a source of glacial biodiversity characterized by species living on the ground but still linked to the presence of cold microclimate ensured by the presence of the glacier few meters far from them.

Aquatic fauna in rivulets on ice (= eukryal) and uppermost reaches of glacierfed streams (=metakryal) is represented mainly by cold hardy non-biting midges that have resistant forms to survive freezing and desiccation. Other guests of

**145**

**Figure 1.**

*Glacial Biodiversity: Lessons from Ground-dwelling and Aquatic Insects*

glacial biodiversity in the current warm stage period.

such habitats are worms (e.g., Naididae and Enchytraeidae) and free-living and

Similar to recently deglaciated terrains, also rock glaciers—which are the best expression of the periglacial environment in alpine areas—can sustain glacial biodiversity, also in the places where there are no glaciers or they disappeared. Currently, the state of knowledge about the animals living on this kind of landform is still very limited; just few sites in Sierra Nevada and on the Alps were investigated [14–16]. Both studies highlighted the presence of microbes, arthropods and small rodent fauna linked to the cold and wet habitat ensured by the presence of interstitial ice. Given the known thermal and hydrologic capacity of rock glaciers to resist warming, this distinct landform has been suggested as potential climatic refugia for

It is therefore evident that glacial biodiversity is characterized by species living in ice-related landforms, thus landforms ensuring, at the ground as well as on the water, average annual temperatures around 0°C [17, 18]. Thus, the species living on and around ice-related landforms can be defined as cryophilous (which means "loving the ice") or cold-adapted species. Among these, the best adapted to survive such extreme habitats are ground beetles (carabids) and non-biting midges

**3. Ground beetles and non-biting midges as flagship organisms: richness** 

Ground beetles (**Figure 1**) occur in almost all terrestrial environments and geographical areas and have different trophic requirements (e.g., predators, seed eaters and phytophagous), it is easy to collect them and their sensitivity to environmental and climate changes is known [19]. In addition, they can be considered among the most important meso- and macrofauna living on recently deglaciated terrains and on the glaciers in terms of species richness and abundance of individuals [13]. Last but not least, there is an ongoing awareness about the extinction risk for some endemic cryophilous species due to the habitat destruction (e.g., glacier

*The ground beetle* Nebria germari *(approx. body length = 1 cm) walking on the Presena Glacier (2700 m a.s.l.) (Adamello-Presanella Mts., Italian Alps) (photo by F. Pupin/archive MUSE).*

*DOI: http://dx.doi.org/10.5772/intechopen.92826*

parasite roundworms.

(chironomids).

**and adaptation**

*Glacial Biodiversity: Lessons from Ground-dwelling and Aquatic Insects DOI: http://dx.doi.org/10.5772/intechopen.92826*

*Glaciers and the Polar Environment*

and still underconsidered [6].

**cryophilous species**

(Rotifera) [11, 12].

landforms (e.g., glaciers and rock glaciers) are detrimental to cold-adapted insects, highly specialized to survive constantly at low temperature, high humidity, deep snow and ice cover. Most of the glaciers are strongly reducing their surface, some are disappearing, others are shifting in debris-covered glaciers and permafrost is melting [5]. The effects of climate change on high-altitude terrestrial and aquatic insect community composition and ecosystem functioning are partially unknown

Scattered studies on high-altitude and high-latitude insect communities are available for most of the glacialized areas of the world, but a synthesis paper merging the most recent advances on cold-adapted insect species living on and at the edge of ice-related landforms is still not available. To fill this gap, the purpose of this chapter is to (i) describe what insects live in glacialized areas, (ii) examine what are the flagship insects in terms of richness and adaptation to cold, (iii) identify threats and opportunities in the current warm-period and (iv) illustrate the role of

**2. Glacial biodiversity: glacial and periglacial landforms as habitat for** 

At first glance, the ground surrounding the glacier front, its surface and the streams originated by the melting glaciers seems to be too extreme to host any life forms. Conversely, there are many organisms that permanently colonize the cryosphere, from bacteria to vertebrates, the so-called glacial biodiversity [7].

From the quantitative point of view, the glacial biodiversity is mainly formed by little (less of 5 cm) or microscopic organisms linked to aquatic, semiaquatic, wet or

The surface of glaciers is colonized by bacteria and algae [8, 9] and mosses, hosting in turn water bears (Tardigrade), roundworms (Nematoda) and potworms (Enchytraeidae) [10]. They can live also directly on the surface of the ice, in cryoconite holes and rivulets on ice. In addition, on the glaciers, it is possible to observe wandering several spiders (Araneae) during the day as well as some ground beetles (Coleoptera: Carabidae) during the night searching for preys. Many other invertebrates, mostly connected with aquatic/wet environments, such as springtails (Collembola), stoneflies (Plecoptera) and non-biting midges (Diptera: Chironomidae), can live directly on the surface of the ice [11]. Moreover, supraglacial cryoconite holes can be considered biodiversity hotspots for invertebrates such as Copepoda, worms (Annelida), water bears, roundworms and wheel animals

Most of the invertebrates living on the glaciers can be found also along recently deglaciated terrains and in the uppermost reach of glacial streams. Thus, the glacial biodiversity living at the edge with the glacier front arrives from two different sinks: falling down from the glacier surface during the melting phases and shifting up along the glacier forelands, transported airborne or by walking. Typically, springtails and moss mites (Oribatida) are the first colonizers of recently deglaciated areas because they are easily transported by the wind, thanks to their lightweight. Some sheet weaver spiders (Linyphiidae) are as well colonizers transported by wind [13]. Thus, recently deglaciated terrains act as a source of glacial biodiversity characterized by species living on the ground but still linked to the presence of cold microcli-

Aquatic fauna in rivulets on ice (= eukryal) and uppermost reaches of glacierfed streams (=metakryal) is represented mainly by cold hardy non-biting midges that have resistant forms to survive freezing and desiccation. Other guests of

mate ensured by the presence of the glacier few meters far from them.

insect communities in the glacial-ecosystem functioning and services.

terrestrial (mainly bare and rocky grounds) habitats.

**144**

such habitats are worms (e.g., Naididae and Enchytraeidae) and free-living and parasite roundworms.

Similar to recently deglaciated terrains, also rock glaciers—which are the best expression of the periglacial environment in alpine areas—can sustain glacial biodiversity, also in the places where there are no glaciers or they disappeared. Currently, the state of knowledge about the animals living on this kind of landform is still very limited; just few sites in Sierra Nevada and on the Alps were investigated [14–16]. Both studies highlighted the presence of microbes, arthropods and small rodent fauna linked to the cold and wet habitat ensured by the presence of interstitial ice. Given the known thermal and hydrologic capacity of rock glaciers to resist warming, this distinct landform has been suggested as potential climatic refugia for glacial biodiversity in the current warm stage period.

It is therefore evident that glacial biodiversity is characterized by species living in ice-related landforms, thus landforms ensuring, at the ground as well as on the water, average annual temperatures around 0°C [17, 18]. Thus, the species living on and around ice-related landforms can be defined as cryophilous (which means "loving the ice") or cold-adapted species. Among these, the best adapted to survive such extreme habitats are ground beetles (carabids) and non-biting midges (chironomids).
