**3.6 Non-biting midges in glacier-fed streams**

Non-biting midges are the main colonizers of glacier-fed streams around the world. Glacially dominated rivers are characterized by a deterministic nature of benthic communities due to the overriding conditions of low water temperature, low channel stability, low food availability and strong daily discharge fluctuations associated to glacier runoff (**Figure 6**). A predictable longitudinal pattern of taxa richness and diversity increasing with distance from the glacier has been described for many European glacier-fed streams, starting from the kryal sector (where maximum water temperature is below 4°C), typically colonized almost exclusively by *Diamesa* species in the temperate regions [53]. *D. steinboecki*, *D. goetghebueri*, *D. tonsa*, *D. zernyi* and *D. bohemani* are the species more frequent and abundant in kryal sites in the Palearctic regions, followed by *D. bertrami*, *D. latitarsis*, *D. modesta*, *D. hamaticornis* and *D. cinerella*. Less frequent are *D. martae*, *D. nowickiana*, *D. longipes*, *D. wuelkeri* and *D. aberrata*; *D. insignipes*, *D. dampfi*, *D. permacra* and

#### **Figure 6.**

*Dubani glacial stream at the glacier snout (3232 m a.s.l., 36°N, 74°E; Bagrote Valley, Karakoram range of northern Pakistan) (photo by L. Latella).*

**153**

changing climate [58].

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

*D. incallida* are rare, being more frequent in glacio-rhithral and krenal habitats, characterized by a lower glacial influence. *D. arctica* is typical of the Arctic regions, and *D. akhrorovi*, *D. alibaevae*, *D. planistyla, D. solhoyi*, *D. aculeate*, *D. praecipua* and *D. khumbugelida* are among the *Diamesa* species typical of Pamir and Tibet mountains. In tropical streams, mainly Podonominae colonize the uppermost glacier-fed stream reaches, while Diamesinae appear more downstream [54]. In glacier-fed streams of New Zealand, [55] reported the mayflies (Ephemeroptera) *Deleatidium cornutum* and *Nesameletus* dominated at the upper sites of glacier-fed streams, with the chironomids *Eukiefferiella* and *Maoridiamesa*. Biodiversity naturally increases with decreasing altitude and increasing distance from the glacier terminus, with a more diversified community downstream of the confluence with tributaries fed by groundwater and rainfall (= krenal and kreno-rhithral). Orthocladiinae and Tanypodinae (e.g., *Zavrelimyia*) become more abundant, followed by Tanytarsini (e.g., *Micropsectra* spp.) in slow-flowing waters where mosses are abundant.

**4. Threats and opportunities for ground beetles and non-biting midges** 

Glaciers and permafrost are disappearing all over the world, and with them, we are risking to lose also the associated glacial biodiversity. Therefore, it is mandatory to describe the temporal and spatial biological fingerprint of climate change

The available literature on ground beetles and non-biting midges is able to give us insights about the threats and opportunities they have in relation to the ongoing

Currently, no ground beetles living on glacial and periglacial landforms have been declared extinct. On the other hand, the temporal reduction in population size of two high-altitude species (*Nebria germari* and *Trechus dolomitanus*) of the Dolomites (Italy) in 30 years was documented [56]. Specifically, local extinction of *Nebria germari* populations was documented in some high-altitude prairies of the Dolomites, and now the species maintain large populations only on glacial and

As observed for ground beetles, also for non-biting midges from kryal habitats, there is no evidence of global extinction of single species, rather of local extinction caused by the retreat of glaciers. The consequence of the glacial retreat is the further isolation of the populations in the short-term and, in the long-term, their possible disappearance due to very restricted habitat preference and limited dispersal abilities of midges. Glacier shrinking favors an upstream shift of lowland euriecious species of chironomid and other invertebrates, associated with an initial decrease in abundance and finally local extinction of kryal *Diamesa* species and other Diamesinae [57]. *Diamesa longipes* and *Syndiamesa nigra* have not been collected in recent years in Alpine running water [53], and the ice fly *Diamesa steinboecki* has disappeared in some glacier-fed streams in the Southern Alps [58]. The strong cold hardiness of *Diamesa* species [59] and the scarcity of potential refuge areas in glacial and periglacial area threaten these species seriously with extinction. Thus, *Diamesa* species have been suggested to be used as sentinels for climate change, especially in relation to glacier retreat. Recent studies found a direct relationship between the loss of *Diamesa* species in alpine riverine environments and the consequences of the

periglacial landforms; thus, it has become an ice-related species.

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

**in relation to climate warming**

impacts to deeply understand trends and patterns.

climate and, consequently, landscape changes.

**4.1 Extinction**

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

*D. incallida* are rare, being more frequent in glacio-rhithral and krenal habitats, characterized by a lower glacial influence. *D. arctica* is typical of the Arctic regions, and *D. akhrorovi*, *D. alibaevae*, *D. planistyla, D. solhoyi*, *D. aculeate*, *D. praecipua* and *D. khumbugelida* are among the *Diamesa* species typical of Pamir and Tibet mountains. In tropical streams, mainly Podonominae colonize the uppermost glacier-fed stream reaches, while Diamesinae appear more downstream [54]. In glacier-fed streams of New Zealand, [55] reported the mayflies (Ephemeroptera) *Deleatidium cornutum* and *Nesameletus* dominated at the upper sites of glacier-fed streams, with the chironomids *Eukiefferiella* and *Maoridiamesa*. Biodiversity naturally increases with decreasing altitude and increasing distance from the glacier terminus, with a more diversified community downstream of the confluence with tributaries fed by groundwater and rainfall (= krenal and kreno-rhithral). Orthocladiinae and Tanypodinae (e.g., *Zavrelimyia*) become more abundant, followed by Tanytarsini (e.g., *Micropsectra* spp.) in slow-flowing waters where mosses are abundant.
