Search results for "Biological dispersal"
showing 10 items of 326 documents
Low male return rate due to clutch enlargements in the pied flycatcher (Ficedula hypoleuca)
1997
Abstract:Increased investment in reproduction during current breeding event may entail future fitness costs. Even though a wide array of both theoretical and empirical work has been devoted to solve the problem of optimal reproductive rate, evidence for costs of reproduction has been equivocal. In the present study we examined the survival of pied flycatcher parents after a clutch size manipulation where we altered clutch size with one or two eggs. We monitored return rates and dispersal of parents during subsequent years after manipulation. An artificial increase in reproductive effort caused lowered return rates of males. Results on breeding dispersal did not support the explanation that …
Does an ant-dispersed plant, Viola reichenbachiana, suffer from reduced seed dispersal under inundation disturbances?
2008
Many plant species use ants as seed dispersers. This dispersal mode is considered to be susceptible to disturbances, but the effect of natural, small-scale disturbances is still unknown. We investigated how small-scale disturbances due to inundation affect seed dispersal in Viola reichenbachiana, a dominant myrmecochorous herb in riparian forests. Inundation disturbances were high in depressions and low on hillocks of the forest floor. We found that V reichenbachiana was similarly abundant at highly and less disturbed sites, contrary to other, non ant-dispersed species. We also found that the motivation of ants to disperse seeds was higher at highly disturbed sites. Nevertheless, the number…
Blowing in the wind: how many roads can a phytoplanktont walk down? A synthesis on phytoplankton biogeography and spatial processes
2015
The selected theme of the 17th Workshop of the International Association for Phytoplankton Taxonomy and Ecology (IAP), ‘‘Biogeography and Spatial Patterns of Biodiversity of Freshwater Phytoplankton,’’ offered the opportunity to explore one neglected aspect of phytoplankton ecology: the distribution of species in the geographic space. This paper summarizes the outcomes of 20 selected contributions among those presented at the workshop. The articles report the results from studies carried out in five continents (only Oceania is not represented) and on a wide array of aquatic ecosystems (deep and shallow natural lakes, man-made lakes, temporary and permanent ponds, rivers). The topics analyze…
Defaunation and biomass collapse of mammals in the largest Atlantic forest remnant
2016
Large continuous rainforests are the main hope for sustaining the population of large-bodied vertebrates that cannot cope with fragmentation or unsustainable hunting. The Brazilian Atlantic forest is considered a biodiversity hotspot and although highly fragmented, it still contains large forest patches that may be important for the conservation of mammals that require large areas. Here, we estimated species richness, density and biomass of medium- and large-sized mammals along the largest remnant of the Atlantic rainforest, Brazil (the Serra do Mar bioregion), an estimated area of 8000 km2. We recorded 44 species based on 4090 km of diurnal line transects and camera traps, animal tracks an…
Is it really you,Orthotrichum acuminatum? Ascertaining a new case of intercontinental disjunction in mosses
2015
Intercontinental disjunct distributions are a main issue in current biogeography. Bryophytes usually have broad distribution ranges and therefore constitute an interesting subject of study in this context. During recent fieldwork in western North America and eastern Africa, we found new populations of a moss morphologically similar to Orthotrichum acuminatum. So far this species has been considered to be one of the most typical epiphytic mosses of the Mediterranean Basin. The new findings raise some puzzling questions. Do these new populations belong to cryptic species or do they belong to O. acuminatum, a species which then has a multiple-continent disjunct range? In the latter case, how c…
Morphological traits predict host-tree specialization in wood-inhabiting fungal communities
2020
Tree species is one of the most important determinants of wood-inhabiting fungal community composition, yet its relationship with fungal reproductive and dispersal traits remains poorly understood. We studied fungal communities (total of 657 species) inhabiting broadleaved and coniferous dead wood (total of 192 logs) in 12 semi-natural boreal forests. We utilized a trait-based hierarchical joint species distribution model to examine how the relationship between dead wood quality and species occurrence correlates with reproductive and dispersal morphological traits. Broadleaved trees had higher species richness than conifers, due to discomycetoids and pyrenomycetoids specializing in them. Re…
Effects of patch number and dispersal patterns on population dynamics and synchrony.
2000
In this paper, we examine the effects of patch number and different dispersal patterns on dynamics of local populations and on the level of synchrony between them. Local population renewal is governed by the Ricker model and we also consider asymmetrical dispersal as well as the presence of environmental heterogeneity. Our results show that both population dynamics and the level of synchrony differ markedly between two and a larger number of local populations. For two patches different dispersal rules give very versatile dynamics. However, for a larger number of local populations the dynamics are similar irrespective of the dispersal rule. For example, for the parameter values yielding stab…
Importance of meteorological variables for aeroplankton dispersal in an urban environment
2016
Passive wind dispersal is one of the major mechanisms through which organisms disperse and colonize new areas. The detailed comprehension of which factors affect this process may help to preserve its efficiency for years to come. This is especially important in the current context of climate change, which may seriously alter weather regimes that drive dispersal, and is crucial in urban contexts, where biodiversity is dramatically threatened by pollution and fragmentation of natural patches. Despite its interest, the analysis of factors affecting aeroplankton dispersal in urban environments is rare in literature. We sampled aeroplankton community uninterruptedly every 4 hours from 17th May t…
Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales
2018
Abstract Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification and the potential for organisms to adapt and persist in response to a changing environment. Recent studies have documented cryptic, sympatric populations of Atlantic cod (Gadus morhua) in coastal areas. We analysed genetic origin of 6,483 individual cod sampled annually over 14 years from 125 locations along the Norwegian Skagerrak coast and document stable coexistence of two gene…
Dispersal flight and colony development in the fungus-growing termites Pseudacanthotermes spiniger and P. militaris
2012
International audience; Pseudacanthotermes spiniger and P. militaris are two African fungus-growing termites (Termitidae, Macrotermitinae) which may become pests in disturbed agrosystems where they often live in sympatry. To study their development and their reproductive strategies, colonies of both species were reared in the laboratory for 20 and 17 years, respectively, after their foundation from reproductive pairs. The first steps of development were in great part similar in both species, although P. spiniger favoured the defence during the juvenile period, while P. militaris tended to favour a rapid development. While P. spiniger colonies did not produce alates until year 7 of colony li…