Search results for "island biogeography"

The use of insular vertebrates in palaeogeographic reconstructions.

2009

Species–area relationship and small-island effect of vascular plant diversity in a young volcanic archipelago

2021

International audience; Aims: Aeolian islands form an active volcanic archipelago. By using updated vascular plant checklists for islands and islets, we tested four hypotheses: (i) Island speciesarea relationship (ISAR) of alien species has lower c-and higher z-values than native species, (ii) islands with active volcanoes have lower species richness than expected for native and alien species, (iii) ISAR of native species shows lower c-and higher z-values than ISARs of Mediterranean land bridge archipelagos and (iv) species richness of smaller islets is independent of area.Location: Aeolian Archipelago, Mediterranean Basin.Taxon: Vascular plants, identified and named according to the Flora …

Plant species richness, biogeographic and conservation interest of the vascular flora of the satellite islands of Sicily: patterns, driving forces an…

2013

The vascular flora has been investigated on about 60 of the approximately 100 islands and islets of the Sicilian archipelago. This paper provides detailed information on the number of exclusive, rare, or threatened vascular plants living on these islands and islets. Focusing on the 18 most-investigated islets, we evaluate the extent to which species richness, rate of endemism, number of alien plants, and number of terrestrial habitats have been influenced by 1) geographical setting, 2) geological history, 3) geo-pedological variability, 4) bioclimate, 5) number and patchiness of local plant communities, and 6) natural and human disturbance history and regime. Special attention is directed t…

Land mammal colonisation of islands is a multifactorial product; a critic to the unwise use of models

2011

The colonization of islands by terrestrial mammals has been the topic of a flurry of studies. Contributions normally tend to oversimplify the subject, focusing on specific key factors which are allegedly considered the best to explain why, how and when non volant terrestrial mammals reached islands and which are used to devise models. The subjectivity in the choice of key factors understandably leads to controversy and debate. Insular faunas are the multifactorial result of complex combinations of facts, conditions and processes. Hence, the faunal assemblages of each island should be inquired individually, on a case-by-case basis. Models, by definition, are simplified representations of rea…

Mediterranean island biogeography: Analysis of fern species distribution in the system of islets around Sicily

2011

The aim of this article was to test the way in which geographical factors influence island floras in the Mediterranean basin, using ferns as target organisms, and the islands surrounding Sicily as location. A matrix with presence/absence data concerning fern taxa in the 16 islands studied was compiled. Cluster analysis, principal co-ordinates analysis (PCoA), principal components analysis (PCA) and a Bayesian analysis were performed. For each island, the total number of fern taxa was regressed against three factors: island area, island elevation and isolation. All the analyses pointed to affinities between islands according to their different geological composition, independently from their…

Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environments.

2018

Plant species tend to retain their ancestral ecology, responding to temporal, geographic and climatic changes by tracking suitable habitats rather than adapting to novel conditions. Nevertheless, transitions into different environments or biomes still seem to be common. Especially intriguing are the tropical alpine-like areas found on only the highest mountainous regions surrounded by tropical environments. Tropical mountains are hotspots of biodiversity, often with striking degrees of endemism at higher elevations. On these mountains, steep environmental gradients and high habitat heterogeneity within small spaces coincide with astounding species diversity of great conservation value. The …

When an island matches a glacial refugium: the case of Sicilian mammals

2011

Network analysis by simulated annealing of taxa and islands of Macaronesia (North Atlantic Ocean)

2018

With the aim of explaining the role that taxa and island features have in biogeographical patterns, we processed presence–absence matrices of all the Macaronesian native species of ten different taxa (arthropods, birds, bryophytes, fungi, lichens, mammals, mollusks, pteridophytes, reptiles and spermatophytes) through simulated annealing analysis. Distribution patterns among the archipelagos were pinpointed, along with the different biogeographic roles played by islands and species groups. All the networks analysed resulted to be significantly modular and the structure of biogeographic modules reflects known past connections among the archipelagos and the current drivers of species distribut…

Supplementary material 1 from: Gehrke B (2018) Staying cool: preadaptation to temperate climates required for colonising tropical alpine-like environ…

2018

Detailed examples on how the coding was done :

Data from: Network analysis by simulated annealing of taxa and islands of Macaronesia (North Atlantic Ocean)

2018

With the aim of explaining the role that taxa and island features have in biogeographical patterns, we processed presence-absence matrices of all the Macaronesian native species of ten different taxa (arthropods, birds, bryophytes, fungi, lichens, mammals, mollusks, pteridophytes, reptiles and spermatophytes) through simulated annealing analysis. Distribution patterns among the archipelagos were pinpointed, along with the different biogeographic roles played by islands and species groups. All the networks analysed resulted to be significantly modular and the structure of biogeographic modules reflects known past connections among the archipelagos and the current drivers of species distribut…