Search results for "Biogeography"
showing 10 items of 310 documents
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…
Global review of recent taxonomic research into Isoetes (Isoetaceae), with implications for biogeography and conservation
2018
With the advent of cytological analysis, Scanning Electron Microscopy, the recognition of sterile hybrids, improved access to wild populations and increasingly comprehensive molecular investigations, there has been a revolution in Isoetes taxonomy in recent times. The last 40 years have seen an almost 100% increase in the diversity documented during the previous two centuries. Four geographic areas account for over 90% of this diversity: northern-central South America, eastern North America, western Eurasia (including the northern Mediterranean) and South to Tropical Africa. There is a significant global conservation concern for Isoetes, with many taxa being rare (known from one to a handfu…
AMMONOID EVOLUTION TRIGGERED BY PALAEOGEOGRAPHIC CHANGES: ORIGIN OF OXFORDIAN SUBFAMILY PASSENDORFERIINAE (SOUTHERN TETHYS)
2011
The comparison of Middle-Upper Jurassic ammonite successions in SW Sicily (Sciacca) and Iberia shows that, during the Middle Jurassic, besides some typical Mediterranean taxa, in Sicily as well as in the Betic Ranges (S Spain) ammonoid successions contain a higher share of typical Submediterranean taxa of Ammonitina, entirely comparable to those recorded in Epicontinental areas of Eastern Iberia. From middle Oxfordian onwards instead, ammonite successions show a clear taxonomic differentiation, being dominated in Sicily by typically Mediterranean taxa (Passendorferiinae) whilst typical Submeditrerranean groups (Perisphinctinae, Oppeliidae) clearly dominant in the Iberian Range, are testimon…
A hidden species becoming visible : biogeography and ecology of Rhynchotalona latens (Cladocera, Anomopoda, Chydoridae)
2019
A long hidden chydorid (Chydoridae, Cladocera) taxon, first found as fossil specimens and recently redefined as Rhynchotalona latens (Sarmaja-Korjonen et al., Hydrobiologia 436: 165-169, 2000) is investigated for its biogeography and ecology. Late Holocene sediment sequence from Lake Sylvilampi, NE Finnish Lapland, and R. latens spatial distribution in relation to limno-climatic attributes in Finland were examined. Principal component analyses of fossil cladoceran communities showed that R. latens is mostly affiliated with Alonella excisa-Alonopsis elongata-Alonella nana species pool. Generalized linear modeling of R. latens responses to limno-climatic variation indicated that it prefers ac…
Origin of the Elements of the endemic "Terre Rosse" fauna (Gargano, South eastern Italy)
2013
The attention of the scientific community has recently been addressed on various aspects of the Messinian endemic vertebrates from the foreland sector of the Abruzzo - Apulian paleobioprovince: several new papers dealing with ruminants, glirids, insectivores, cricetids, as well as with biochronological, palaeographic and biogeographic aspects have been published in the last ten years. New fossils finds enriched the taxonomic composition of the Gargano endemic fauna: a new Cricetodontinae genus, a new Murinae genus representing the direct ancestor of the endemic murid Mikrotia, and a new species of primitive giant moonrat Deinogalerix. The recently published taxonomic description of the smal…
Diversité microbienne des sols : stratégie méthodologique, distribution spatiale et traduction en fonctionnement biologique
2011
International audience; Since the development of industrialization, urbanization and agriculture, soils have been subjected to numerous variations in environmental conditions, which have resulted in modifications of the taxonomic diversity and functioning of the indigenous microbial communities. As a consequence, the functional significance of these losses/modifications of biodiversity, in terms of the capacity of ecosystems to maintain the functions and services on which humanity depends, is now of pivotal importance. In this context, one of the main challenges in soil microbial ecology is to better understand and predict the processes that drive soil microbial diversity and the link betwe…
Gastropods from upper Pliensbachian–Toarcian (Lower Jurassic) sediments of Causses Basin, southern France and their recovery after the early Toarcian…
2015
AbstractA gastropod fauna has been studied from upper Pliensbachian – upper Toarcian deposits of two sections of the Causses Basin (southern France) in order to investigate the mode of recovery after the early Toarcian anoxic event. The fauna consists of 15 species, one of which is new (Bathrotomaria kronzwilmesorumsp. nov.). Their stratigraphical distribution shows two peaks of diversity – in the Bifrons Zone (Bifrons Subzone) and in the Aalensis Zone (Mactra Subzone) – which reflect brief times during which the oxygen content and bottom consistency favoured the settlement of a relatively diversified fauna. In the Variabilis–Pseudoradiosa zones, gastropods are only represented by two speci…
Ecological specialization to fluctuating resources prevents long-distance migratory raptors from becoming sedentary on islands
2013
[Background]: The adaptive transition between behavioral strategies, such as the shift from migratoriness to sedentariness, remains an outstanding question in evolutionary ecology. Density-dependent variation in the age of first breeding has been proposed as a feasible mechanism through which long-lived migratory birds with deferred sexual maturity should become sedentary to persist on islands. Although this pattern seems to hold for most raptors and herons, a few exceptions have been identified. One of these exceptions is the Eleonora's falcon, a long-distance migratory bird, which shows one of the most peculiar adaptations in the timing of reproduction and food requirements among raptors.…
First description of the male of Phlebotomus betisi Lewis and Wharton, 1963 (Diptera: Psychodidae).
2008
The male of Phlebotomus (Larroussius) betisi is described from Malayan caves. Several males have been caught in association with P. betisi females. Males and females have been associated by ecology, biogeography, morphology and molecular biology (homology of the ND4 mtDNA sequences).
Factors affecting between-lake variation in the occurrence of epidermal papillomatosis in roach,Rutilus rutilus(L.)
2009
The theory of island biogeography predicts that the probability of a species occupying an island depends on a dynamic equilibrium between extinction and colonization. Epidermal papillomatosis is a disease manifesting as skin tumours on fish. We studied the factors affecting the occurrence of the disease in roach, Rutilus rutilus (L.), in 34 lakes. The results of discrimination analysis suggest that maximum depth, percentage of the drainage area of the lake covered by lakes in the vicinity and altitude best identified diseased lakes. Comparison of diseased and non-diseased lakes revealed that lake area could also be regarded as a variable contributing to the occurrence of the disease. The sa…