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1.
RAINER HUTTERER TIZIANO MADDALENA OBDULIA M. MOLINA 《Biological journal of the Linnean Society. Linnean Society of London》1992,46(1-2):49-58
Until recently the North Atlantic Islands were believed to house only mammals introduced by humans. Recent work has demonstrated that at least the Canary Islands house(d) a native mammal fauna. New data including chromosome numbers, genetic distances and analysis of vocalizations are given for the two extant shrew species, Crocidura canariensis and C. osorio , and their possible sister taxa are evaluated. Evidence is presented for the hypothesis that the two island species originated from two different lineages of the Palaearctic branch of the genus Crocidura. The data support the present status of the Canary Island shrews as local endemics of high conservation priority. 相似文献
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Aim The aim of this paper is to investigate the causes of the current restricted distribution of a narrow-range endemic bird species, the Canary Islands stonechat, Saxicola dacotiae .
Location Eastern islands of the Canary Islands archipelago.
Methods We compared climatic patterns (temperature and rainfall), habitat and microhabitat structure, food availability during a full annual cycle, and the abundance of native avian competitors and predators inside and outside the species' range. Three study areas, located in similar habitats on nearby islands, were studied: northern Fuerteventura, close to the northern border of the species' range; southern Lanzarote, 22 km from the nearest site occupied by stonechats; and the Lobos islet, 10 km from the nearest occupied site and 2 km from the coast of Fuerteventura.
Results The cover of suitable habitats (slopes with high cover of large shrubs, stony fields and ravines) and microhabitats (shrubs and boulders) and the abundance of arthropods during the breeding period of Canary Islands stonechats were lower outside than inside the species' range. Temperature, rainfall and the abundance of competitors and predators inside and outside the species' range did not differ significantly.
Main conclusions Ecological requirements explaining the distribution of the Canary Islands stonechat within its range seem to be the main factor hindering its settlement on nearby islands. Geological and palaeoclimatic processes, as well as past and current human impact, could also have constrained the distribution of this narrow-range endemic bird species. 相似文献
Location Eastern islands of the Canary Islands archipelago.
Methods We compared climatic patterns (temperature and rainfall), habitat and microhabitat structure, food availability during a full annual cycle, and the abundance of native avian competitors and predators inside and outside the species' range. Three study areas, located in similar habitats on nearby islands, were studied: northern Fuerteventura, close to the northern border of the species' range; southern Lanzarote, 22 km from the nearest site occupied by stonechats; and the Lobos islet, 10 km from the nearest occupied site and 2 km from the coast of Fuerteventura.
Results The cover of suitable habitats (slopes with high cover of large shrubs, stony fields and ravines) and microhabitats (shrubs and boulders) and the abundance of arthropods during the breeding period of Canary Islands stonechats were lower outside than inside the species' range. Temperature, rainfall and the abundance of competitors and predators inside and outside the species' range did not differ significantly.
Main conclusions Ecological requirements explaining the distribution of the Canary Islands stonechat within its range seem to be the main factor hindering its settlement on nearby islands. Geological and palaeoclimatic processes, as well as past and current human impact, could also have constrained the distribution of this narrow-range endemic bird species. 相似文献
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R. S. THORPE M. BAEZ 《Biological journal of the Linnean Society. Linnean Society of London》1993,48(1):75-87
The lacertid lizard ( Gallotia stehlini ), an endemic of Gran Canaria, shows no visually obvious geographic variation, yet all seven scalation characters that were examined exhibit significant geographic variation. The number of collar scales, scales along the ventral trunk and femoral pores are correlated with habitat type, while the number of femoral pores is correlated negatively with altitude. Mantel tests were used to compare simultaneously an observed pattern with three hypothesized patterns (habitat type, altitude and proximity). They indicate that, while several individual characters are significantly associated with the putative causal factors of habitat type and altitude, there is no association between an overall scalation distance matrix and habitat type, or altitude when the effect of proximity is removed. Consequently, one should consider the individual characters as well as the multivariate generalized distances. Some of the observed patterns of geographic variation in scalation are very similar to those of the small scincid lizard Chalcides sexlineatus on Gran Canaria and also parallel the altitudinal and latitudinal variation in the scalation of the Tenerife lacertid ( Galotia galloti ). The low level of congruence in patterns of geographic variation in individual characters (i.e. some vary with latitude, some with altitude and one varies with longitude) is consistent with the hypothesis that ecogenetically caused geographic variation may result in lower inter-character congruence than phylogenetically caused geographic variation. 相似文献
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Pedro Cardoso Miquel A. Arnedo Kostas A. Triantis Paulo A. V. Borges 《Journal of Biogeography》2010,37(6):1034-1046
Aim To identify the biogeographical factors underlying spider species richness in the Macaronesian region and assess the importance of species extinctions in shaping the current diversity. Location The European archipelagos of Macaronesia with an emphasis on the Azores and Canary Islands. Methods Seven variables were tested as predictors of single‐island endemics (SIE), archipelago endemics and indigenous spider species richness in the Azores, Canary Islands and Macaronesia as a whole: island area; geological age; maximum elevation; distance from mainland; distance from the closest island; distance from an older island; and natural forest area remaining per island – a measure of deforestation (the latter only in the Azores). Different mathematical formulations of the general dynamic model of oceanic island biogeography (GDM) were also tested. Results Island area and the proportion of remaining natural forest were the best predictors of species richness in the Azores. In the Canary Islands, area alone did not explain the richness of spiders. However, a hump‐shaped relationship between richness and time was apparent in these islands. The island richness in Macaronesia was correlated with island area, geological age, maximum elevation and distance to mainland. Main conclusions In Macaronesia as a whole, area, island age, the large distance that separates the Azores from the mainland, and the recent disappearance of native habitats with subsequent unrecorded extinctions seem to be the most probable explanations for the current observed richness. In the Canary Islands, the GDM model is strongly supported by many genera that radiated early, reached a peak at intermediate island ages, and have gone extinct on older, eroded islands. In the Azores, the unrecorded extinctions of many species in the oldest, most disturbed islands seem to be one of the main drivers of the current richness patterns. Spiders, the most important terrestrial predators on these islands, may be acting as early indicators for the future disappearance of other insular taxa. 相似文献
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Guilhem Mansion Federico Selvi Alessia Guggisberg Elena Conti 《Journal of Biogeography》2009,36(7):1282-1296
Aim The presence of numerous reliable fossils and the occurrence of many endemic island species make the Boraginales particularly suitable for integrative biogeographical studies. In this paper we aim to elucidate the time frame and events associated with the origin of selected borages endemic to the Mediterranean climate zone. More specifically, we describe and examine the alternative palaeo‐ and neoendemic hypotheses for their origin. Location Corsica and Sardinia (continental fragment islands) and the Canary Islands (an oceanic island archipelago). Methods Eighty‐nine accessions, representing 30 genera from five families ascribed to the Boraginales, were examined for six chloroplast DNA regions. We used an integrative approach including phylogenetic analyses (Mr Bayes ), Bayesian molecular dating (T3 package) with four fossil constraints on nodes, and biogeographical reconstructions (diva ) to elucidate the temporal and spatial origins of the Corso‐Sardinian and Canary Island endemics. Results Species of Echium endemic to the Canary Islands diverged from their continental sister clade during the Miocene (15.3 ± 5.4 Ma), probably after the rise of the oldest islands (c. 20 Ma). Corso‐Sardinian endemics of Borago diverged from their primarily North African sister clade during the late Miocene‐Pliocene (c. 6.9 ± 3.6 Ma), well after the initial fragmentation of the islands (c. 30 Ma). Similarly, Corso‐Sardinian endemics of Anchusa diverged from the South African Anchusa capensis during the Pliocene–Pleistocene (c. 2.7 ± 2.1 Ma). Main conclusions The present study reveals an Anatolian origin for Anchusa, Borago and Echium and underlines the importance of the Eastern Mediterranean region as a possible reservoir for plant evolution in the Mediterranean Basin. For Anchusa and Borago, the divergence from their respective sister clades on the two types of islands post‐dated the formation of the islands, thus supporting the neo‐endemic hypothesis, whereas the dating results for the origin of Echium endemics were less conclusive. 相似文献
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Aim Oceanic islands represent a special challenge to historical biogeographers because dispersal is typically the dominant process while most existing methods are based on vicariance. Here, we describe a new Bayesian approach to island biogeography that estimates island carrying capacities and dispersal rates based on simple Markov models of biogeographical processes. This is done in the context of simultaneous analysis of phylogenetic and distributional data across groups, accommodating phylogenetic uncertainty and making parameter estimates more robust. We test our models on an empirical data set of published phylogenies of Canary Island organisms to examine overall dispersal rates and correlation of rates with explanatory factors such as geographic proximity and area size. Location Oceanic archipelagos with special reference to the Atlantic Canary Islands. Methods The Canary Islands were divided into three island‐groups, corresponding to the main magmatism periods in the formation of the archipelago, while non‐Canarian distributions were grouped into a fourth ‘mainland‐island’. Dispersal between island groups, which were assumed constant through time, was modelled as a homogeneous, time‐reversible Markov process, analogous to the standard models of DNA evolution. The stationary state frequencies in these models reflect the relative carrying capacity of the islands, while the exchangeability (rate) parameters reflect the relative dispersal rates between islands. We examined models of increasing complexity: Jukes–Cantor (JC), Equal‐in, and General Time Reversible (GTR), with or without the assumption of stepping‐stone dispersal. The data consisted of 13 Canarian phylogenies: 954 individuals representing 393 taxonomic (morphological) entities. Each group was allowed to evolve under its own DNA model, with the island‐model shared across groups. Posterior distributions on island model parameters were estimated using Markov Chain Monte Carlo (MCMC) sampling, as implemented in MrBayes 4.0, and Bayes Factors were used to compare models. Results The Equal‐in step, the GTR, and the GTR step dispersal models showed the best fit to the data. In the Equal‐in and GTR models, the largest carrying capacity was estimated for the mainland, followed by the central islands and the western islands, with the eastern islands having the smallest carrying capacity. The relative dispersal rate was highest between the central and eastern islands, and between the central and western islands. The exchange with the mainland was rare in comparison. Main conclusions Our results confirm those of earlier studies suggesting that inter‐island dispersal within the Canary Island archipelago has been more important in explaining diversification within lineages than dispersal between the continent and the islands, despite the close proximity to North Africa. The low carrying capacity of the eastern islands, uncorrelated with their size or age, fits well with the idea of a historically depauperate biota in these islands but more sophisticated models are needed to address the possible influence of major recent extinction events. The island models explored here can easily be extended to address other problems in historical biogeography, such as dispersal among areas in continental settings or reticulate area relationships. 相似文献
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We describe 10 polymorphic tetranucleotide microsatellite loci from the eastern Canary Island lacertid lizard, Gallotia atlantica. Loci were isolated from a partial genomic library that had been enriched for AAAG repeat sequence. All loci were highly polymorphic (eight alleles or more) with observed heterozygosities from 0.75 to 1.00. At least four loci were successfully amplified and polymorphic in the Gran Canarian lacertid, Gallotia stehlini. These loci will be used to examine correlations between patterns of gene flow and recent volcanism on the island of Lanzarote. 相似文献
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Martin Haase Carola Greve Rainer Hutterer Bernhard Misof 《Zoological Journal of the Linnean Society》2014,171(1):92-107
Time‐trees are commonly calibrated based on fossils attributed to internal nodes, thus defining the minimum age of these nodes. However, in the absence of synapomorphies, the phylogenetic position of a fossil can only be inferred based on similarity. In this study, we objectively allocated fossil shells to internal nodes based on the reconstruction of ancestral shapes and sizes in a geometric morphometric framework. Our phylogenetic analysis of 24 (putative sub)species was based on 2524 amplified fragment length polymorphism loci. In this well‐supported tree the taxa occurring in north‐west Africa and on the Iberian peninsula were paraphyletic with respect to the (sub)species from the Canary and Selvagen Islands, indicating a continental origin of the genus in contrast to our earlier sequence‐based account. Ancestral shell shapes and sizes were inferred based on landmark data using squared‐change parsimony. In a subsequent principal component analysis, only three of 20 fossil shells could be unequivocally allocated to internal nodes. However, these fossils were all Quaternary, and thus too young to infer meaningfully narrow confidence intervals for divergence estimates that probably reach back into the Miocene or even Oligocene. The apparent failure of allocating older fossils to internal nodes and achieving a reliable tree calibration was caused by the absence of phylogenetic signal in the shells of Theba due to extensive, sometimes rapid, convergent evolution, including reversals. © 2014 The Linnean Society of London 相似文献
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Antn Prez‐Rodríguez lvaro Ramírez David S. Richardson Javier Prez‐Tris 《Global Ecology and Biogeography》2013,22(12):1272-1281
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Simone Fattorini 《Journal of Biogeography》2010,37(6):1061-1070
Aim To investigate the importance of various island characteristics in determining spatial patterns of variations in beta diversity for various animal groups. Location Analyses are presented for 10 animal groups living on the Aeolian Islands, a volcanic archipelago in the central Mediterranean, near Sicily. Methods Three hypotheses were formulated to explain patterns of beta diversity: the target‐area–distance effect, stepping stone dispersal and island age. Matrices of inter‐island dissimilarities were constructed under each hypothesis and correlated with matrices of faunal dissimilarities using Mantel tests. For the ‘target‐area–distance effect’ hypothesis, inter‐island dissimilarities were calculated using island sizes and distances to nearest mainland areas. For the ‘stepping stone dispersal’ hypothesis, inter‐island distances were measured. Finally, for the ‘island age’ hypothesis, inter‐island dissimilarities were calculated on the basis of the geological age of the islands. Cluster analysis was used to investigate inter‐island faunal relationships. Results Support for a target‐area–distance effect was found only for birds. For these highly mobile animals, inter‐island distances had no significant effects on beta diversity. Birds are known to colonize islands by crossing large sea barriers and thus they can easily reach the Aeolian Islands, which are close to source areas (notably Sicily). Inter‐island distances had a significant role in determining patterns of beta diversity in most invertebrates. For Mollusca, Opiliones, Chilopoda, Heteroptera, coprophagous Scarabaeoidea, and Tenebrionidae, even relatively short distances preclude invertebrates from colonizing an island regularly from the mainland, and most colonization probably results from inter‐island faunal exchanges. Island age was proved to be important only for orthopterans. Main conclusions The origin of most of the Aeolian invertebrate fauna is quite recent, and species appear to have established on the islands predominantly by stepping stone dispersal. Birds, which are highly mobile organisms, follow more direct mainland–island dynamics. As further studies on other islands become available, comparative analyses will confirm whether the factors influencing variations in beta diversity in this study and their relationships with species dispersal ability are consistent across scales and geographical context. 相似文献
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AGUEDO MARRERO RAFAEL S. ALMEIDA MANUEL GONZÁLEZ-MARTÍN 《Botanical journal of the Linnean Society. Linnean Society of London》1998,128(3):291-314
The arborescent taxa of Dracaena which form the dragon tree group comprise five species found in Macaronesia, Morocco (D. draco), East Africa (D. ombet, D. schizantha), Arabia (D. serrulata) and the island of Socotra (D. cinnabari). A new species of dragon tree, Dracaena tamaranae A. Marrero, R. S. Almeida & M. Gonzalez-Martin, is described from Gran Canaria, Canary Islands. This new species differs from D. draco, the only other Dracaena species currently known in Macaronesia, in having a growth form and inflorescence type and leaves more similar to the East African and Arabian species of Dracaena. In contrast, D. draco appears to be related to D. cinnabari. In this paper, we also present a study of the taxonomy, habitat and ecology of all the species of the dragon tree group. These are found in thermo-sclerophyllous plant communities of tropical-subtropical regions which are rather xerophilous and have a rainfall range of 200–500 mm. Our study indicates two independent colonization events for Dracaena in Macaronesia. In addition, we suggest that the dragon tree group provides an example of two major biogeographical disjunctions between East and West Africa. We postulate that this group has a Tethyan origin, a hypothesis supported by fossil and palaeoclimatic data, and thus parallels the distribution and dispersal pattern of other taxonomic groups. 相似文献
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A. Traveset M. Nogales J. A. Alcover J. D. Delgado M. López-Darias D. Godoy J. M. Igual P. Bover 《Biological invasions》2009,11(7):1653-1670
Invasions of alien rodents have shown to have devastating effects on insular ecosystems. Here we review the ecological impacts
of these species on the biodiversity of the Balearic and the Canary Islands. A total of seven species of introduced rodents
(two rats, three mice, one dormouse, and one squirrel) have been recorded (six in the Balearics and four in the Canaries).
Some of them can occasionally be important predators of nesting seabirds, contributing to the decline of endangered populations
in both archipelagos. Rats are also known to prey upon terrestrial birds, such as the two endemic Canarian pigeons. Furthermore,
rats actively consume both vegetative and reproductive tissues of a high number of plants, with potential relevant indirect
effects on vegetation by increasing erosion and favoring the establishment of alien plants. In the Balearics, rats and mice
are important seed predators of endemic species and of some plants with a restricted distribution. In the Canaries, rats intensively
prey upon about half of the fleshy-fruited tree species of the laurel forest, including some endemics. In both archipelagos,
alien rodents disrupt native plant–seed dispersal mutualisms, potentially reducing the chances of plant recruitment at the
same time that they modify the structure of plant communities. We further suggest that alien rodents played (and play) a key
role in the past and present transformation of Balearic and Canarian native ecosystems. 相似文献
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Aim We analyse the influence of different factors on the inter‐insular colonization processes that yielded the current distribution pattern of endemic reptile species in the Canary Islands. Location The seven main islands of the Canary Islands. Methods We tested 11 hypotheses about factors that might have affected the colonization processes. We used Mantel and partial Mantel tests to establish the statistical significance of the relationship between the islands predicted by each hypothesis, and a parsimony analysis to detect the most parsimonious hypothesis. Results The only significant relationships were those predicted by inter‐island distance, also taking area into account, and habitat similarity, considering current vegetation in the islands. The latter was the best hypothesis according to the parsimony criterion. Main conclusions Our results support the hypothesis that habitat similarity between islands is the main factor affecting the colonization processes of the whole group, although inter‐insular distance seems to play a separate role in colonization events. 相似文献