Search results for "DISPERSAL"
showing 10 items of 465 documents
Exotic Guavas are Foci of Forest Regeneration in Kenyan Farmland
2007
Fruiting trees in degraded areas are attractive for frugivorous birds and may become centers of regeneration. However, a number of tree species in degraded areas are exotic species. Thus, the question arises whether these exotic species can also act as foci for forest regeneration. In the farmland adjacent to Kakamega Forest, Kenya, we investigated the frugivore assemblage in, and seed rain and seedling establishment under, 29 fruiting exotic guava trees (Psidium guajava) at different distances to the forest. The results show that 40 frugivorous bird species visited guava trees. All of the seed and 82 percent of the seedling species found under the treecrowns were animal dispersed, 58 and 5…
Taxonomic uncertainty and a continental conundrum:Polypodium macaronesicumreassessed
2014
Data from the chloroplast trnL-F region are used to test the delimitation of putative diploid species in the Polypodium cambricum aggregate. In particular, we investigate the distinctiveness of the Macaronesian Polypodium macaronesicum, P. azoricum and the continental P. cambricum, investigate molecular diversity patterns within Macaronesia and establish the identity of putative P. macaronesicum material collected from an area in southern Spain, where it co-occurs with other Macaronesian elements. The analysis supports the distinction of Macaronesian and continental plants, with accessions from Macaronesia resolved as monophyletic. Greater haplotype diversity was found in Macaronesia than o…
Rare and threatened pondweed communities in anthropogenic water bodies of Opole Silesia (SW Poland)
2011
The paper presents results of geobotanic studies conducted in anthropogenic water bodies like excavation ponds, fish culture ponds, other ponds, dam reservoirs, ditches, channels and recreational pools incl. watering places in Opole Silesia and surroundings in the years 2002-2005. The research focused on occurrence of threatened and rare pondweed communities. As the result of the investigations of several dozen of water bodies, 28 localities of rare pondweed communities were documented by 75 phytosociological relevés. Associations of <em>Potametum trichoidis</em> J. et R Tx. in R. Tx. 1965, <em>Potametum praelongi</em> Sauer 1937, <em>P. alpini</em> Br.-B…
Modeling initial Neolithic dispersal. The first agricultural groups in West Mediterranean
2015
Abstract In previous research, the SE-NW time-trend in the age of the earliest Neolithic sites across Europe has been treated as a signal of a global-scale process that brought farming/herding economies to the continent. Residual variation from this global time-trend is generally treated as ‘noise’. A Complex Adaptive Systems perspective views this empirical record differently. The apparent time-trend is treated as an emergent consequence of the interactions of individuals and groups of different scale. Here, we examine the dynamics of agricultural dispersals, using the rich body evidence available from the Iberian Peninsula as a case study. We integrate two complementary approaches: (1) cr…
Energy and speleogenesis: Key determinants of terrestrial species richness in caves
2017
Abstract The aim of this study was to unravel the relative role played by speleogenesis (i.e., the process in which a cave is formed), landscape‐scale variables, and geophysical factors in the determination of species richness in caves. Biological inventories from 21 caves located in the southeastern Iberian Peninsula along with partial least square (PLS) regression analysis were used to assess the relative importance of the different explanatory variables. The caves were grouped according to the similarity in their species composition; the effect that spatial distance could have on similarity was also studied using correlation between matrices. The energy and speleogenesis of caves account…
Should dispersers be fast learners? Modeling the role of cognition in dispersal syndromes.
2021
Abstract Both cognitive abilities and dispersal tendencies can vary strongly between individuals. Since cognitive abilities may help dealing with unknown circumstances, it is conceivable that dispersers may rely more heavily on learning abilities than residents. However, cognitive abilities are costly and leaving a familiar place might result in losing the advantage of having learned to deal with local conditions. Thus, individuals which invested in learning to cope with local conditions may be better off staying at their natal place. In order to disentangle the complex relationship between dispersal and learning abilities, we implemented individual‐based simulations. By allowing for develo…
Modelling the shrub encroachment in a grassland with a Cellular Automata Model
2018
Abstract. Arid and semi-arid grasslands of southwestern North America have changed dramatically over the last 150 years as a result of shrub encroachment, i.e. the increase in density, cover and biomass of indigenous shrubby plants in grasslands. Numerous studies have documented the expansion of shrublands in the southwestern American grasslands; in particular shrub encroachment has occurred strongly in part of the northern Chihuahuan desert since 1860. This encroachment has been simulated using an ecohydrological Cellular Automata model, CATGraSS. It is a spatially distributed model driven by spatially explicit irradiance and runs on a fine-resolution gridded domain. Plant competition is m…
Data from: The Pillars of Hercules as a bathymetric barrier to gene-flow promoting isolation in a global deep-sea shark (Centroscymnus coelolepis)
2015
Knowledge of the mechanisms limiting connectivity and gene-flow in deep-sea ecosystems is limited, especially for deep-sea sharks. The Portuguese dogfish (Centroscymnus coelolepis) is a globally distributed and Near Threatened deep-sea shark. C. coelolepis population structure was studied using 11 nuclear microsatellite markers and a 497 bp fragment from the mtDNA Control Region. High levels of genetic homogeneity across the Atlantic (ΦST=-0.0091, FST= 0.0024, P > 0.05) were found suggesting one large population unit at this basin. The low levels of genetic divergence between Atlantic and Australia (ΦST= 0.0744, P<0.01; FST=0.0015, P > 0.05) further suggested that this species may …
Data from: Patterns of ecological diversification in thelodonts
2018
Here we explore the spatial, temporal and phylogenetic patterns of ecological diversification for the entire clade of thelodonts, one of the earliest groups of vertebrates and longest lasting of the Palaeozoic agnathans in the fossil record. Parsimony and maximum-likelihood methods are used to reconstruct ancestral states of their geographical distributions, habitats and lifestyles. Our results support the concept that thelodonts originated during the Middle?–Late Ordovician probably in marine open waters of Laurasia, with a demersal lifestyle on hard substrates being the ancestral condition for the whole clade. Later, thelodonts underwent a complex ecological diversification and palaeobiog…
Data from: Evidence for an association between post-fledging dispersal and microsatellite multilocus heterozygosity in a large population of greater …
2014
Dispersal can be divided into three stages: departure, transience and settlement. Despite the fact that theoretical studies have emphasized the importance of heterozygosity on dispersal strategies, empirical evidence of its effect on different stages of dispersal is lacking. Here, using multi-event capture-mark-recapture models, we show a negative association between microsatellite multilocus heterozygosity (MLH; 10 loci; n = 1023) and post-fledging dispersal propensity for greater flamingos, Phoenicopterus roseus, born in southern France. We propose that the negative effects of inbreeding depression affects competitive ability and therefore more homozygous individuals are more likely to di…