Time filter

Source Type

Keil P.,Charles University | Biesmeijer J.C.,University of Leeds | Barendregt A.,University Utrecht | Reemer M.,Netherlands Center for Biodiversity | Kunin W.E.,University of Leeds
Ecography | Year: 2011

We test whether temporal change in species richness (ΔS [%]) is scale-dependent, using data on hoverflies from the UK and the Netherlands. We analysed ΔS between pre-1980 and post-1980 periods using 5 grid resolutions (10×10, 20×20, 40×40, 80×80 and 160×160km). We also tested the effect of data quality and of unequal survey periods on ΔS estimates, and checked for spatial autocorrelation of ΔS estimates. Using data from equal survey periods, we found significant increases in hoverfly species richness in the Netherlands at fine scales, but no significant change at coarser scales indicating a decrease in beta diversity. In the UK, ΔS was negative at fine scale, near zero at intermediate scales, and positive at coarse scales, indicating that the degree of spatial beta diversity increased between the time periods. The use of unequal survey periods (using longer periods in the past to compensate for lower survey intensity) tended to inflate past species richness, biasing ΔS estimates downwards. High data quality thresholds sometimes obscured dynamics by reducing sample size, but never reversed trends. There was little spatial autocorrelation of ΔS, implying that local drivers (land use change or environmental noise) are important in dynamics of hoverfly diversity. A second, sample agglomeration approach to measure scaling resulted in greater noise in ΔS, obscuring the NL pattern, while still showing strong evidence of fine-scale richness loss in the UK. Our results indicate that explicit considerations of spatial (and temporal) scale are essential in studies documenting past biodiversity change, or projecting change into the future. © 2011 The Authors. Ecography © 2011 Ecography.

The species-rich fossil vertebrate assemblage from Pleistocene sedimentary deposits at Kisláng, Hungary, was originally described as containing eight species of arvicolids, six of which were considered new. Re-examination of the material in the collection of the Hungarian Geological Institute, consisting of most of the previously described material, including the six name-bearing types and also further undescribed specimens, indicates that the taxa Kislangia rex, Mimomys cf. hassiacus, Mimomys coelodus, Mimomys pusillus, Mimomys tornensis, Pitymimomys sp., Borsodia newtoni, Lagurodon arankae and Allophaiomys deucalion are present. Most of these species are compatible with Early Pleistocene age close to the boundary between the Villányian and Biharian regional stages (MQR10, MQ1, c.1.6-2.0Ma). However, the specimen of Mimomys cf. hassiacus is of approximately mid-Pliocene age (MN15 c.3.6-4.0Ma), and one of the Pitymimomys specimens is referable to P. stenokorys, described from the earliest Pleistocene (MNR2-MNR3, MN17 c.2.3-2.4Ma). The assemblage is therefore interpreted as derived from at least three different geological periods and because of reworking of material is considered unusable to characterize any particular stratigraphic level. These conclusions are placed in the context of historical and current biostratigraphies. © The Palaeontological Association.

Hoeksema B.W.,Netherlands Center for Biodiversity
Raffles Bulletin of Zoology | Year: 2012

The distribution patterns of 37 mushroom coral species (Scleractinia: Fungiidae) were studied on 13 reefs in the Spermonde Archipelago (Makassar Strait, Indonesia) in 1984-1986. The studied reefs were either cay-crowned or submerged and were divided over four shelf zones varying in distance offshore. The species are compared with regard to their distributions (1) across the shelf in four zones parallel to the coastline, (2) around the reefs with orientation according to wind directions, and (3) along depth gradients over the reef flats, slopes, and bases. Most species showed their highest abundances on wave-exposed mid-shelf reef slopes. Within transects, species showed overlapping depth ranges, visible as multi-species assemblages with average densities in quadrats of up to 25 m-2 composed of a maximum of 26 co-occurring species. Most species were a concentrated on reef slopes, some mainly on shallow reef flats, and a few on deeper reef bases. Several species showed a downward shift in depth range with increasing distance offshore. A clustering of the reefs with respect to similarity in species composition appeared to be related to their distance offshore and to the presence or absence of shallow reef substrates important for recruitment. Use of the Fungiidae as a model taxon of phylogenetically closely related coral species in comparisons of their distribution patterns helps to gain insight with regard to their ecological differentiation along environmental gradients in coastal reef areas. © National University of Singapore.

Casanovas-Vilar I.,Autonomous University of Barcelona | Garcia-Paredes I.,CSIC - National Museum of Natural Sciences | Alba D.M.,University of Florence | van den Hoek Ostende L.W.,Netherlands Center for Biodiversity | Moya-Sola S.,Autonomous University of Barcelona
Journal of Biogeography | Year: 2010

Aim: To analyse the diversity dynamics of Miocene mammalian faunas in the Iberian Peninsula in order to determine whether the patterns are related to the dispersal of taxa from other areas into this region. Location: Mainly the Iberian Peninsula, but two close geographical areas (Central Europe and the Eastern Mediterranean) are also considered in some of our calculations. Methods: Genus-level faunal lists for a total of 299 localities from the Iberian Peninsula, covering 10 successive biochronological units [Mammal Neogene (MN) zones] that span from the latest Early Miocene to the early Pliocene (about 17-4 Ma), were compiled. The dataset was expanded with a further 331 localities in Central Europe and the Eastern Mediterranean for the same time span. Next, a taxonomically standardized database was used to create composite faunal lists of micro- and macromammalian genera present during each MN zone. Separate genera-by-MN-zone matrices for both micro- and macromammals were built for each region. Mean standing diversity as well as origination and extinction rates were calculated for the Iberian Peninsula, and their correlation with preservation rates is discussed. Simpson's coefficient of faunal similarity with Central Europe and the Eastern Mediterranean was calculated in order to evaluate whether diversity patterns were related to changes in the affinity of the Iberian mammalian faunas with those of other regions. Results: Diversity changes in the Iberian macromammalian faunas coincide with periods of increased faunal similarity with other regions, suggesting a relationship to the expansions and contractions of the geographical ranges of the constituent taxa. This pattern is not recognized for micromammals; that is, their diversity trends are not related to changes in geographical ranges. Main conclusions: Climatic shifts result in expansions or contractions in the geographical ranges of macromammals, owing to changes in the distribution of their preferred habitats. The lower dispersal ability of micromammals results in a higher extinction risk when habitat fragmentation confines their populations to relatively small environmental patches. Hence, they are more severely affected by climatic changes. Our results thus emphasize the role of climatic forcing in mammalian biogeography and diversity. © 2010 Blackwell Publishing Ltd.

Prieto J.,Senckenberg Institute | van den Hoek Ostende L.W.,Netherlands Center for Biodiversity | Hir J.,Nograd Megyei Muzeumi Szervezet
Bulletin of Geosciences | Year: 2012

Large and well preserved micro-mammal faunas are available from the Middle Miocene from Hungary, but very little attention was paid on insectivores, although this group provides good palaeoenvironmental and palaeogeographical indication. As a first step we review the material from Sámsonháza 3 (Hungary, Nógrád County), based on both published and new fossils. We report the dimylid Plesiodimylus sp., the soricid cf. Paenelimnoecus sp. and an indeterminate shrew. The erinaceids Parasorex sp. and Lantanotherium sp., and the talpid Desmanodon sp. are described for the first time from Hungarian deposits. The fauna indicates a relatively wet environment and is in agreement with the Middle Badenian correlation proposed on the basis of the rich molluscan fauna of the locality.

Discover hidden collaborations