Search results for "Dispersal"
showing 10 items of 465 documents
Origin and age of Australian Chenopodiaceae
2005
Abstract We studied the age, origins, and possible routes of colonization of the Australian Chenopodiaceae. Using a previously published rbc L phylogeny of the Amaranthaceae–Chenopodiaceae alliance (Kadereit et al. 2003) and new ITS phylogenies of the Camphorosmeae and Salicornieae, we conclude that Australia has been reached in at least nine independent colonization events: four in the Chenopodioideae, two in the Salicornieae, and one each in the Camphorosmeae, Suaedeae, and Salsoleae. Where feasible, we used molecular clock estimates to date the ages of the respective lineages. The two oldest lineages both belong to the Chenopodioideae ( Scleroblitum and Chenopodium sect. Orthosporum / Dy…
Detection of steering direction using EEG recordings based on sample entropy and time-frequency analysis.
2016
Monitoring driver's intentions beforehand is an ambitious aim, which will bring a huge impact on the society by preventing traffic accidents. Hence, in this preliminary study we recorded high resolution electroencephalography (EEG) from 5 subjects while driving a car under real conditions along with an accelerometer which detects the onset of steering. Two sensor-level analyses, sample entropy and time-frequency analysis, have been implemented to observe the dynamics before the onset of steering. Thus, in order to classify the steering direction we applied a machine learning algorithm consisting of: dimensionality reduction and classification using principal-component-analysis (PCA) and sup…
Out of Asia: Mitochondrial DNA Evidence for an Oriental Origin of Tiger Frogs, Genus Hoplobatrachus
2001
Most examples of intercontinental dispersal events after the Miocene contact between Africa and Asia involve mammal lineages. Among amphibians, a number of probably related groups are known from both continents, but their phylogenies are so far largely unresolved. To test the hypothesis of Miocene dispersal against a Mesozoic vicariance scenario in the context of Gondwana fragmentation, we analyzed fragments of the mitochondrial 16S rRNA gene (572 bp) in 40 specimens of 34 species of the anuran family Ranidae. Results corroborated the monophyly of tiger frogs (genus Hoplobatrachus), a genus with representatives in Africa and Asia. The African H. occipitalis was the sister group of the Asian…
Spore production monitoring reveals contrasting seasonal strategies and a trade‐off between spore size and number in wood‐inhabiting fungi
2023
1. Traits related to reproduction and dispersal drive the assembly and dynamics of species communities and can explain and predict how species respond to habitat loss and fragmentation and to the changing climate. For fungi, such links remain poorly known. 2. We examine how spore production rate, a key demographic trait, is influenced by the interaction between environmental conditions and species traits. We monitored the spore production of 97 wood-inhabiting fungal species on 107 decaying logs for two years and analyzed the data with a hierarchical community model. 3. Our analysis demonstrates clear species differences in seasonal patterns, with spring and summer release dominating in per…
Post-fledging dependence period and onset of natal dispersal in Bearded Vultures (Gypaetus barbatus): new insights from GPS satellite telemetry.
2014
Utilizamos telemetría satelital para estudiar el periodo de dependencia post emplumamiento de tres individuos silvestres y seis individuos cautivos de Gypaetus barbatus. El primer vuelo tuvo lugar cuando los pollos tenían 126 ± 7 días de edad (rango = 111–134 días) y el inicio de la dispersión ocurrió a los 193 ± 40 días desde el primer vuelo (rango = 143–231 días). Los jóvenes permanecieron en sus áreas natales (o de liberación, en el caso de aves criadas en cautiverio) durante los primeros dos meses desde la fecha de emplumamiento. Luego, comenzaron a incrementar progresivamente la distancia a sus áreas natales; durante este tiempo, la mayoría de los desplazamientos de larga distancia…
Detection of tick-borne encephalitis virus in I. ricinus ticks collected from autumn migratory birds in Latvia.
2014
Birds have a potential of spreading ticks via bird migration routes. In this study, we screened 170 ticks removed during autumn 2010 from 55 birds belonging to 10 species for the presence of tick-borne encephalitis virus (TBEV). In total, TBEV RNA was detected in 14% of I. ricinus tick samples obtained from different birds species. The results of this study indicate the possible role of migrating birds in the dispersal of TBEV-infected ticks along the southward migration route.
Population structure of Brachidontes pharaonis (P. Fisher, 1870) (Bivalvia, Mytilidae) in the Mediterranean Sea, and evolution of a novel mtDNA polym…
2006
Abstract Brachidontes pharaonis (Fisher P, 1870) is an Indo-Pacific mussel that has colonized the Mediterranean Sea via the Suez Canal. Mussels may have migrated by natural dispersal of pelagic larvae, or they may have been transported on the hulls of ships, or in ballast water, or by some combination of these. Mitochondrial COI sequences (618 bp) from 101 mussels from six localities in the central and eastern Mediterranean Sea and from one site in the Red Sea were used to describe population structure. Analysis of molecular variance indicated that frequencies differed among populations, and that 92% of the variation resided within populations. The majority of haplotypes were private allele…
Über spezialisierte Verbreitungseinrichtungen anatolischer Galieae
1971
Summary Some annual species of the Rubiaceae native in Anatolia are specialized in their methods of seed dispersal. Contrary to other members of the genus, the frucitficence of Cruriata articulata with its persisting bracts falls to pieces which act as ‘surface:rollers’ transported by the wind. Valantia hispida and Callipeltis cucullaria are heterodissmeniate. Some of the mericarps arc dispersed by different agents, the other ones stay attached to the plant, showing a form of atelechory, a common phenomenon in arid regions. Other aberrant forms of dissemination are studied.
Contrasting Effects of Chronic Anthropogenic Disturbance on Activity and Species Richness of Insectivorous Bats in Neotropical Dry Forest
2022
For prioritizing conservation actions, it is vital to understand how ecologically diverse species respond to environmental change caused by human activity. This is particularly necessary considering that chronic human disturbance is a threat to biodiversity worldwide. Depending on how species tolerate and adapt to such disturbance, ecological integrity and ecosystem services will be more or less affected. Bats are a species-rich and functionally diverse group, with important roles in ecosystems, and are therefore recognized as a good model group for assessing the impact of environmental change. Their populations have decreased in several regions, especially in the tropics, and are threatene…
Specialization and interaction strength in a tropical plant–frugivore network differ among forest strata
2011
The degree of interdependence and potential for shared coevolutionary history of frugivorous animals and fleshy-fruited plants are contentious topics. Recently, network analyses revealed that mutualistic relationships between fleshy-fruited plants and frugivores are mostly built upon generalized associations. However, little is known about the determinants of network structure, especially from tropical forests where plants' dependence on animal seed dispersal is particularly high. Here, we present an in-depth analysis of specialization and interaction strength in a plant-frugivore network from a Kenyan rain forest. We recorded fruit removal from 33 plant species in different forest strata (…