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Latella L.,Sezione di Zoologia | Verdari N.,Sezione di Zoologia | Gobbi M.,Sezione di Zoologia degli Invertebrati e Idrobiologia
Zoological Studies | Year: 2012

Distribution of terrestrial cave-dwelling arthropods in two adjacent Prealpine Italian areas with different glacial histories. Zoological Studies 51(7): 1113-1121. The aim of this study was to investigate the distribution of cave-dwelling arthropod communities in 2 adjacent karst areas with different glacial histories. Endemic and obligate cave-dwelling faunas were recorded in 60 caves located in 2 adjacent Prealpine areas (in Veneto, northeastern Italy): the Baldo and Lessinia Mountain groups were compared. During the last glacial period, the Baldo Mountain group was completely surrounded and isolated from the Lessinia group by the Adige glacier, while the Lessinia was only partially surrounded. The effect of glacial isolation, both geographically (cave locations) and elevationally (cave elevation), on the faunal distribution was tested using the number of troglobiont and endemic species collected in each area. The Lessinia hosts a higher number of troglobiont species and a lower number of endemic species compared to those of the Baldo area. Furthermore, results indicated that the similarity in species assemblages in caves was not driven by their geographic location, but by colonization patterns caused by isolation created by the Adige glacier during the last ice age. This suggests that the geographic isolation of the Baldo area during Quaternary climatic fluctuations determined the species which colonized the caves and consequently prevented multiple colonizations during warm periods. Glacier-induced isolation during the last ice age can therefore be considered one of the main factors which determined terrestrial arthropod colonization of caves in the Prealps area. Source


Brambilla M.,Sezione di Zoologia dei Vertebrati | Gobbi M.,Sezione di Zoologia degli Invertebrati e Idrobiologia
Ecography | Year: 2014

Climate change is affecting species distribution, composition of biological communities, and species traits. Despite the growing body of knowledge on the reaction of species to climate change, the potentially delayed response of species is still severely understudied. In this paper we modelled the time needed by ground-living invertebrates to effectively react to habitat modification induced by climate change in relation to dispersal abilities. We analyzed the occurrence pattern of alpine ground beetles (carabids) along areas recently freed by retreating glaciers in the central-eastern Italian Alps, to test how the synergic effects of time since deglaciation and environmental factors may affect the colonisation process. Different times of response to climate change in ground beetles were found. Sites already hosting the land cover type suitable for our study taxon, but ice-free for less than 100 yr, are mainly colonised by winged carabid beetles (which have high dispersal abilities and are mostly habitat generalists). No, or very few, wingless species (slow colonizers and ecologically specialized) occur within those sites. The overall pattern suggests that within a site, suitable land cover is established prior to colonization, due to a strong joint effect of time since deglaciation and land cover type. Long-lasting habitat development at the fine scale is likely to result in a lack of specific resources (e.g. food items, or microhabitat), which is likely to contribute to delayed colonisation, which potentially could be tied also to dispersal abilities. Whatever the reason, the existence of a time-lag often equal to or greater than 100 yr in species colonisation implies caution in predicting species' occurrence shifts following climate change. © 2013 The Authors. Source


Tampucci D.,University of Milan | Gobbi M.,Sezione di Zoologia degli Invertebrati e Idrobiologia | Boracchi P.,Struttura Complessa di Statistica Medica | Cabrini E.,University of Milan | And 5 more authors.
Biodiversity | Year: 2015

Primary successions along glacier forelands are perfect examples of the changing climate upon high mountain ecosystems. Peripheral mountain ranges deserve particular attention, given they are characterised by high numbers of species and endemism and are considered to be particularly susceptible to climate change. We analysed thermal regime, soil parameters and plant/arthropod primary succession along a glacier foreland located in such a context, comparing it with those previously studied in the inner Alps. The overall patterns of the investigated primary succession agree with those of the inner Alps at the same elevation, but stands out for a delayed plant and arthropod colonisation which promotes the long-lasting persistence of pioneer cold-adapted species. In light of the results obtained, and considering the glaciological features of peripheral mountain ranges (glaciers persistence at low elevation), this paper asserts the hypothesis that glacial landforms of these areas may act as warm-stage refugia for pioneer cold-adapted species. © 2015 Biodiversity Conservancy International. Source


Tenan S.,Sezione di Zoologia dei Vertebrati | Maffioletti C.,Sezione di Zoologia degli Invertebrati e Idrobiologia | Caccianiga M.,University of Milan | Compostella C.,University of Milan | And 2 more authors.
Ecological Modelling | Year: 2016

Chronosequences of glacier retreat are useful for investigating primary successions over time periods that are longer than direct observation would permit. In this context, space-for-time substitution studies have been applied to assess the effects of climate change on invertebrate assemblages. However, population dynamics of insect species following retreating glaciers has been under-investigated until now due to difficulty in applying capture-recapture methods and correctly identifying species in the field. Removal sampling methods are commonly used, but imperfect detectability is rarely accounted for in the analytical framework. In this paper we study the effects of environmental drivers of spatial, and indirectly temporal, variation in population size and sex-ratio of cold-adapted insects through a hierarchical framework for abundance. We show the importance of a metapopulation design, where samples are replicated in space and time, to model data from small and scattered populations, typically present in habitats with climate-mediated selective pressure like those along glacier forelands. This scattered distribution can influence the observation or sampling process and thus species detectability. Our results show that glacier retreat differently affects species-specific changes of population size and sex ratio along the chronosequence, even if the species are taxonomically related. Small-sized populations occur on the glacier surface, near the glacier front, and in sites deglaciated for at least 100 yrs. On the contrary, larger populations occupy sites deglaciated for more than 20 yrs, but less than 100 yrs. This pattern is described by the concave relationship of abundance with both species richness of other arthropods (proxy of habitat complexity) and soil organic matter (proxy of soil maturity). Sex-ratio showed opposite patterns in relation to time since deglaciation. Hierarchical models that estimate abundance of spatially distinct subpopulations represent useful tools for accurately assessing changes in species abundance following climate change while accounting for possible bias associated with imperfect detectability, an issue which is often neglected in space-for-time substitution studies on invertebrates and, more generally, in studies involving pitfall trapping. © 2016 Elsevier B.V. Source


Pizzolotto R.,University of Calabria | Gobbi M.,Sezione di Zoologia degli Invertebrati e Idrobiologia | Brandmayr P.,University of Calabria
Ecology and Evolution | Year: 2014

Very little is known about fferent responses to climate change of animal the changes of ground beetle assemblages in the last few decades in the Alps, and dipopulations living above and below the treeline have not been estimated yet. This study focuses on an altitudinal habitat sequence from subalpine spruce forest to alpine grassland in a low disturbance area of the southeastern Dolomites in Italy, the Paneveggio Regional Park. We compared the ground beetle (Carabidae) populations sampled in 1980 in six stands below and above the treeline (1650-2250 m a.s.l.) with those sampled in the same sites almost 30 years later (2008/9). Quantitative data (species richness and abundance) have been compared by means of several diversity indexes and with a new index, the Index of Rank-abundance Change (IRC). Our work shows that species richness and abundance have changed after almost 30 years as a consequence of local extinctions, uphill increment of abundance and uphill shift of distribution range. The overall species number dropped from 36 to 27, while in the sites above the treeline, species richness and abundance changed more than in the forest sites. Two microtherm characteristic species of the pioneer cushion grass mats, Nebria germari and Trechus dolomitanus, became extinct or showed strong abundance reduction. In Nardetum pastures, several hygrophilic species disappeared, and xerophilic zoophytophagous elements raised their population density. In forest ecosystems, the precipitation reduction caused deep soil texture and watering changes, driving a transformation from Sphagnum-rich (peaty) to humus-rich soil, and as a consequence, soil invertebrate biomass strongly increased and thermophilic carabids enriched the species structure. In three decades, Carabid assemblages changed consistently with the hypothesis that climate change is one of the main factors triggering natural environment modifications. Furthermore, the level of human disturbance could enhance the sensitivity of mountain ecosystems to climate change. © 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Source

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