Plant and arthropod colonisation of a glacier foreland in a peripheral mountain range

Marano

et al. 2017

Boreas

Self Cite

Active rock glaciers are periglacial landforms consisting of coarse debris with interstitial ice or ice-core. Recent studies showed that such landforms are able to support plant and arthropod life and could act as warm-stage refugia for cold-adapted species due to their microclimate features and thermal inertia. However, integrated research comparing active rock glaciers with surrounding landforms to outline their ecological peculiarities is still scarce. We analysed the abiotic (ground surface temperature and humidity, soil physical and chemical parameters) and biotic (plant and arthropod communities) features of two Alpine active rock glaciers with contrasting lithology (silicate and carbonate), and compared them with the surrounding iceless landforms as reference sites (stable slopes and active scree slopes). Our data show remarkable differences between stable slopes and unstable landforms as a whole, while few differences occur between active scree slopes and active rock glaciers: such landforms show similar soil features but different ground surface temperatures (lower on active rock glaciers) and different occurrence of cold-adapted species (more frequent/abundant on active rock glaciers). Both plant and arthropod species distributions depend mainly on the geographical context as a function of soil pH and on the contrast between stable slopes and unstable landforms as a function of the coarse debris fraction and organic matter content, while the few differences between active scree slopes and active rock glaciers can probably be attributed to microclimate. The role of active rock glaciers as potential warm-stage refugia for cold-adapted species is supported by our data; however, at least in the European Alps, their role in this may be less important than that of debris-covered glaciers, which are able to host cold-adapted species even below the climatic tree line.

Section: Discussionmentioning

confidence: 97%

Ecology of active rock glaciers and surrounding landforms: climate, soil, plants and arthropods

Tampucci

Marano

et al. 2017

Boreas

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“…glacier forelands) (see Hagvar, 2012). Spatial distribution of ground-dwelling arthropods is mainly determined by site age (time since deglaciation), with its related local fine-scale environment conditions, such as soil grain size, vegetation cover, and/or soil organic matter (see, Kaufmann, 2001;Brambilla & Gobbi, 2014;Tampucci et al, 2015). More recently, attention has shifted from the glacier forelands to the surface of debris-covered glaciers, because of the emerging interest of debris-covered glaciers as suitable habitats for micro-, meso-and macro-fauna and plant life (Caccianiga et al, 2011;Gobbi et al, 2011;Azzoni et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Life in harsh environments: carabid and spider trait types and functional diversity on a debris‐covered glacier and along its foreland

Ballarin

Brambilla

et al. 2017

Ecological Entomology

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1. Patterns of species richness and species assemblage composition of ground‐dwelling arthropods in primary successions along glacier forelands are traditionally described using a taxonomic approach. On the other hand, the functional trait approach could ensure a better characterisation of their colonisation strategies in these types of habitat. 2. The functional trait approach was applied to investigate patterns of functional diversity and life‐history traits of ground beetles and spiders on an alpine debris‐covered glacier and along its forefield in order to describe their colonisation strategies. 3. Ground beetles and spiders were sampled at different successional stages, representing five stages of deglaciation. 4. The results show that the studied glacier hosts ground beetle and spider assemblages that are mainly characterised by the following traits: walking colonisers, ground hunters and small‐sized species. These traits are typical of species living in cold, wet, and gravelly habitats. The diversity of functional traits in spiders increased along the succession, and in both carabids and spiders, life‐history traits follow the ‘addition and persistence model’. Accordingly, there is no turnover but there is an addition of new traits and a variation in their proportion within each species assemblage along the succession. The distribution of ground beetles and spiders along the glacier foreland and on the glacier seems to be driven by dispersal ability and foraging strategy. 5. The proposed functional approach improves knowledge of the adaptive strategies of ground‐dwelling arthropods colonising glacier surfaces and recently deglaciated terrains, which represent landforms quickly changing due to global warming.

“…Both spider taxonomic diversity and species richness were not spatially correlated at any spatial scales (Table I). This suggests that spiders are less sensitive to the spatial distances between plots/ areas than carabid beetles are, probably because of the high dispersal abilities -for example, some species/families are able to move via ballooning, in some cases at both the juvenile and adult stages (Weyman 1993), this favouring wider dispersal (Tampucci et al 2015).…”

Section: Resultsmentioning

confidence: 99%

Patterns of spatial autocorrelation in the distribution and diversity of carabid beetles and spiders along Alpine glacier forelands

Italian Journal of Zoology

Brambilla

2016

Spatial autocorrelation is a common feature of ecological data and can be found in the distribution pattern of many species or in the diversity of many species assemblages. The presence of spatial autocorrelation in species distribution along primary successions on recently deglaciated terrains has been largely overlooked until now, despite its potential consequences for comparisons between glacier forelands. Here, we investigated the occurrence of spatial autocorrelation at different spatial scales in the distribution and diversity of ground beetles and spiders along glacier forelands. We found positive spatial autocorrelation in patterns of occurrence of most species and in patterns of species assemblages diversity at spatial scales representing single (< 3 km) or adjacent valleys (< 7 km), whereas at a larger spatial scales (0-30 km) such positive spatial autocorrelation disappeared. We concluded that spatial autocorrelation could be a key issue for studies investigating distribution of arthropods, including in glacier forelands, in order to perform more robust analysis and to avoid misinterpretation of species distribution in relation to the glacier retreat and other environmental characteristics.