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Aim: To identify the effect of multiple, temporally close, forcing events (i.e. climate‐driven habitat fragmentations/homogenizations) in shaping current patterns of biodiversity in alpine areas. Given their spatial configuration, alpine areas have been traditionally seen as islands surrounded by an "ocean" of unsuitable lands. A quantitative assessment of the effects of Holocene climate fluctuations on islands area and inter‐island connectivity is crucial to finely reconstruct past biodiversity dynamics and forecast species responses to future changes. Location: Italy. Taxa: Carabidae (Ground beetles), Chrysomelidae (Leaf beetles), Elateridae (Click beetles), Orthoptera (Grasshoppers and Crickets) and Papilionoidea (Butterflies and Skippers). Methods: A total of 1,077 species for 128,093 records were analysed and a classification based on their functional traits allowed identifying groups of good and poor dispersers within each taxon. A dynamic discrete model of ecosystem evolution provided the spatio‐temporal context to test two competing (transient equilibria vs. nonequilibrium) dynamics based on different colonization capabilities. In the transient equilibria dynamic the species are able to respond to island evolution through successful dispersal and colonization events, whereas in the nonequilibrium dynamic ineffective immigration constrains the current species richness to that generated by the strongest island contraction. Results: With the exception of Elateridae, good dispersers (Chrysomelidae and Papilionoidea) responded to environmental changes by establishing a series of transient equilibria. In contrast, the nonequilibrium dynamic better described patterns of species richness in poor dispersers (Carabidae and Orthoptera). Main conclusions: Our approach could be used as the basis for the development of spatially and temporally explicit models of island evolution and could be a valuable tool for quantifying the sensitivity of single taxa to climate‐driven habitat changes. It also represents a further step towards the forecasting of future responses to climate change and the accompanying development of conservation strategies that more effectively respond to the detrimental impacts of climate change on biodiversity. [ABSTRACT FROM AUTHOR]

Aim Bats communicate by emitting social calls, and these often elicit reactions in conspecifics. Many such vocalizations are species-specific so that unambiguous signals can be transmitted and interpreted by conspecifics. In species-rich assemblages, evolutionary pressures might prompt interspecific diversification of call structure so that communication with heterospecifics is avoided. In species-poor island communities, where no risk of miscommunication occurs, stabilizing selection should prevail and preserve call structure and function. Call structure in island bats might be inherited from colonizers from the mainland and be maintained with little change in the absence of selection from heterospecifics. To test this hypothesis we studied Pipistrellus maderensis, an insular taxon occurring on the Madeira Archipelago, the Canary Islands and the Azores. It is closely related to one of the most widespread European pipistrelles, Pipistrellus kuhlii. Pipistrellus maderensis most probably evolved from a common ancestor shared with P. kuhlii, or from founders of that taxon that colonized the islands. We hypothesized that on Madeira Island, where no risk of ambiguous communication with heterospecifics exists, the structure and function of social calls should have been preserved by stabilizing selection. Echolocation calls, subject to different selection pressures, may instead show more pronounced differences between P. maderensis and P. kuhlii. Location Madeira Island (Portugal, Atlantic Ocean), central and southern Italy. Methods We recorded social and echolocation calls from allopatric populations of the two pipistrelles and explored interspecific differences in time and frequency characteristics. We also conducted playback experiments by broadcasting recordings of social calls from P. kuhlii and P. maderensis (taken respectively in peninsular Italy and on Madeira) and monitoring the bats’ responses. Results Social call structure showed a strong similarity between species, whereas echolocation calls were markedly different and exhibited a mean divergence of over 6 kHz in their frequency of maximum energy. On Madeira, P. maderensis significantly reduced flight activity when we broadcast P. kuhlii signals, as did P. kuhlii in Italy in response to P. maderensis calls. Main conclusions Reliable interpretation of social calls provides benefits to both the signaller and the receiver because signals help to optimize food exploitation at foraging sites. In the absence of closely related species that can emit similar calls, this advantage may have acted as a strong evolutionary pressure, stabilizing social call structure in P. maderensis in insular ecosystems with limited foraging resources. [ABSTRACT FROM AUTHOR]

Aim To investigate the biological meaning of equations used to apply the general dynamic model (GDM) of oceanic island biogeography proposed by R. J. Whittaker, K. A. Triantis and R. J. Ladle. Location Analyses are presented for 17 animal groups living on the Aeolian Islands, a volcanic archipelago in the central Mediterranean, near Sicily. Methods In addition to the mathematical implementation of the GDM proposed by Whittaker, Triantis and Ladle, and termed here logATT2 ( , where S is species number or any other diversity metric, t is island age, A is island area, and a, b, c and d are fitted parameters), a new implementation based on the Arrhenius equation of the species–area relationship (SAR) is investigated. The new model (termed powerATT2) is: . For logATT2 and powerATT2 models, equations were developed to calculate (1) the expected number of species at equilibrium (i.e. when the island has reached maturity) per unit area ( Seq), and (2) the time required to obtain this value ( teq). Whereas the intercept in the Gleason model ( S = C + z log A) or the coefficient of the Arrhenius power model ( S = CA z) of the SAR can be considered measures of the expected number of species per unit area, this is not the case for the parameter a of the ATT2 models. However, values of Seq can be used for this purpose. The index of ‘colonization ability’ (CAB), calculated as the ratio , may provide a measure of the mean number of species added per unit area per unit time. Results Both ATT2 models fitted most of the data well, but the powerATT2 model was in most cases superior. Equilibrial values of species richness ( Seq) varied from c. 3 species km−2 (reptiles) to 100 species km−2 (mites). The fitted curves for the powerATT2 model showed large variations in d, from 0.03 to 3. However, most groups had values of d around 0.2–0.4, as commonly observed for the z-values of SARs modelled by a power function. Equilibration times ranged from about 170,000 years to 400,000 years. Mites and springtails had very high values of CAB, thus adding many more species per unit area per unit time than others. Reptiles and phytophagous scarabs showed very low values, being the groups that added fewest species per unit area per unit time. Main conclusions Values of equilibrial species richness per unit area are influenced by species biology (e.g. body size and ecological specialization). Theoretical and empirical evidence suggests that higher immigration rates should increase the z-values of the Arrhenius model. Thus, in the same archipelago, groups with larger z-values should be characterized by higher dispersal ability. Results obtained here for the parameter d conform to this prediction. [ABSTRACT FROM AUTHOR]