**8. Conclusions**

The questions posed in the 'Introduction' section can be answered in the following way:


## **b.** *Questions about zoological succession*

where ancient carbon was assimilated by Diptera larvae, mainly Chironomidae. In a foreland without ponds, a possible release of ancient carbon can be checked by radiocarbon dating chironomid larvae from the glacier river. A peculiar thing is that if invertebrates, which had assimilated old carbon, had been recovered as subfossils and radiocarbon dated, their age had been overestimated by up to 1100 years [29]. Since several pioneer species were herbivores on biofilm or mosses, the present succession did not fit with the 'predator-first' hypothesis. Although pioneer species may be ecologically very different, the pioneer community is surprisingly predictable, both within Norwegian forelands and in the Alps, and several genera are in common [32]. We need to improve our knowledge about the autecology of the individual species to better understand their position and functional role in the succession process. From each species´ point of view, colonising the foreland is a question of fulfilling minimum ecological demands. For instance, analyses of gut content were the key to understand the pioneer food web in the present foreland [29, 31]. Experimental studies involving transportation and re-location of species could be rewarding, but would it for the sake of science be ethically acceptable to

**Figure 18.** In plot no. 18 (age 180 years, see Figure 1), 12 soil cores were taken. This example shows how the cumulative number of mite taxa increased with increasing number of cores. However, none of the single cores contained all taxa

move species within a 'natural laboratory' that should develop in a natural way?

Southern Alps [50].

(columns).

170 Glacier Evolution in a Changing World

A negative and special aspect by melting glaciers is that their meltdown will threaten coldadapted invertebrates which live near glaciers. Especially when it comes to endemic, coldadapted species, melting glaciers represent an extinction threat, as in certain mountains of the

