Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 12 de 12
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Biol Futur ; 74(4): 457-465, 2023 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-37479862

RESUMEN

The Natura 2000 network is one of the most important tools for nature conservation in the EU. Therefore, knowledge of the ecology of the species listed on the Habitats Directive annexes is of particular relevance. One of these species is the butterfly Euphydryas aurinia. Much is already known about the ecology of this species at the European level, but information on Romania is scarce. Therefore, in a study area northwest of Cluj, the species was intensively studied in a mark-release-recapture study over its entire flight period. The investigated population harboured many individuals and had a high density. The dispersal behaviour of the individuals was somewhat more pronounced than in Mediterranean and partly also high alpine populations, but roughly comparable to other populations of the nominotypic subspecies. Overall, the ecological differences to Central and Western European populations were not very pronounced, and many of the conservation-relevant statements on this species in Central Europe should also be largely valid in Romania.


Asunto(s)
Mariposas Diurnas , Fritillaria , Animales , Europa (Continente) , Rumanía , Humedales
2.
Sci Rep ; 12(1): 5175, 2022 03 25.
Artículo en Inglés | MEDLINE | ID: mdl-35338196

RESUMEN

Several morphological and mitochondrial lineages of the alpine ringlet butterfly species Erebia pronoe have been described, indicating a complex phylogenetic structure. However, the existing data were insufficient and allow neither a reconstruction of the biogeographic history, nor an assessment of the genetic lineages. Therefore, we analysed mitochondrial (COI, NDI) and nuclear (EF1α, RPS5) gene sequences and compared them with sequences from the sister species Erebia melas. Additionally, we combined this information with morphometric data of the male genitalia and the infection patterns with Wolbachia strains, based on a WSP analysis. We obtained a distinct phylogeographic structure within the E. pronoe-melas complex with eight well-distinguishable geographic groups, but also a remarkable mito-nuclear discordance. The mito-nuclear discordance in E. melas and E. pronoe glottis can be explained by different ages of Wolbachia infections with different Wolbachia strains, associated selective sweeps, and hybridisation inhibition. Additionally, we found indications for incipient speciation of E. pronoe glottis in the Pyrenees and a pronounced range dynamic within and among the other high mountain systems of Europe. Our results emphasize the importance of combined approaches in reconstructing biogeographic patterns and evaluating phylogeographic splits.


Asunto(s)
Mariposas Diurnas , Síndrome MELAS , Wolbachia , Animales , Mariposas Diurnas/genética , ADN Mitocondrial/genética , Variación Genética , Masculino , Filogenia , Wolbachia/genética
3.
PLoS One ; 15(1): e0227352, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31945077

RESUMEN

The article presents the radiocarbon investigation of the baobab of Jhunsi, Allahabad and the Parijaat tree at Kintoor, two old African baobabs from northern India. Several wood samples extracted from these baobabs were analysed by using AMS radiocarbon dating. The radiocarbon date of the oldest samples were 779 ± 41 BP for the baobab of Jhunsi and 793 ± 37 BP for the baobab of Kintoor. The corresponding calibrated ages are 770 ± 25 and 775 ± 25 calendar years. These values indicate that both trees are around 800 years old and become the oldest dated African baobabs outside Africa.


Asunto(s)
Adansonia/crecimiento & desarrollo , Datación Radiométrica/métodos , Árboles/crecimiento & desarrollo , Madera/análisis , India
4.
Front Zool ; 16: 1, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30675174

RESUMEN

BACKGROUND: Habitat quality is one main trigger for the persistence of butterflies. The effects of the influencing biotic and abiotic factors may be enhanced by the challenging conditions in high-alpine environments. To better our knowledge in this field, we performed a mark-release-recapture study with Boloria pales in the Southern Carpathians. METHODS: We analysed population structure, movement and foraging behaviour to investigate special adaptations to the alpine environment and to reveal differences between sexes. We compared these aspects in one sector with and one sector without grazing to address the effects of grazing intensity on habitat quality. RESULTS: We observed "soft" protandry, in which only a small number of males appeared before females, and an extended emergence of individuals over the observed flight period, dividing the population's age structure into three phases; both observations are considered adaptations to high mountain environments. Although both sexes were mostly sedentary, movement differences between them were obvious. Males flew larger distances than females and were more flight-active. This might explain the dimorphism in foraging behaviour: males preferred nectar sources of Asteraceae, females Caprifoliaceae. Transition from the grazed to the ungrazed sector was only observed for males and not for females, but the population density was higher and the flight distances of the individuals were significantly longer on the grazed sector compared with the ungrazed one. CONCLUSION: Soft protandry, an extended emergence of the individuals and an adapted behavioural dimorphism between sexes render to represent a good adaptation of B. pales to the harsh environmental conditions of high mountain ecosystems. However, land-use intensity apparently has severe influence on population densities and movement behaviour. To protect B. pales and other high-alpine species from the negative consequences of overgrazing, areas without or just light grazing are needed.

5.
Nat Plants ; 4(7): 505, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-29967518

RESUMEN

In Supplementary Table 1 originally published with this Brief Communication, the authors gave an incorrect GPS easterly coordinate for tree number 12 (Makulu Makete Big baobab); the coordinate '2° 34.584' S, 25° 52.261' E' should have read '22° 34.584' S, 28° 52.261' E'. This has now been amended in the online Supplementary Information file for this Brief Communication.

6.
Nat Plants ; 4(7): 423-426, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29892092

RESUMEN

The African baobab is the biggest and longest-living angiosperm tree. By using radiocarbon dating we identified the stable architectures that enable baobabs to reach large sizes and great ages. We report that 9 of the 13 oldest and 5 of the 6 largest individuals have died, or at least their oldest parts/stems have collapsed and died, over the past 12 years; the cause of the mortalities is still unclear.


Asunto(s)
Adansonia , Adansonia/crecimiento & desarrollo , África del Sur del Sahara , Tallos de la Planta/crecimiento & desarrollo , Datación Radiométrica , Árboles/crecimiento & desarrollo , Madera/crecimiento & desarrollo
7.
Sci Rep ; 7: 46323, 2017 04 12.
Artículo en Inglés | MEDLINE | ID: mdl-28402336

RESUMEN

Studies investigating host-parasite systems rarely deal with multispecies interactions, and mostly explore impacts on hosts as individuals. Much less is known about the effects at colony level, when parasitism involves host organisms that form societies. We surveyed the effect of an ectoparasitic fungus, Rickia wasmannii, on kin-discrimination abilities of its host ant, Myrmica scabrinodis, identifying potential consequences at social level and subsequent changes in colony infiltration success of other organisms. Analyses of cuticular hydrocarbons (CHCs), known to be involved in insects' discrimination processes, revealed variations in chemical profiles correlated with the infection status of the ants, that could not be explained by genetic variation tested by microsatellites. In behavioural assays, fungus-infected workers were less aggressive towards both non-nestmates and unrelated queens, enhancing the probability of polygyny. Likewise, parasitic larvae of Maculinea butterflies had a higher chance of adoption by infected colonies. Our study indicates that pathogens can modify host recognition abilities, making the society more prone to accept both conspecific and allospecific organisms.


Asunto(s)
Hormigas/parasitología , Conducta Animal , Hongos/fisiología , Interacciones Huésped-Parásitos , Micosis , Animales , Hormigas/química , Hidrocarburos/análisis
8.
Ambio ; 45(4): 480-9, 2016 May.
Artículo en Inglés | MEDLINE | ID: mdl-26729244

RESUMEN

Large, old trees are keystone ecological structures, their decline having disproportional ecological consequences. There is virtually no information available regarding the status and occurrence of old trees in traditional cultural landscapes from Eastern Europe. In this study, we explore the environmental determinants of the old oaks found in wood-pastures from a changing traditional rural landscape from Central Romania. Both the old oaks and the wood-pastures harboring them have exceptional cultural, historical, and ecological values, yet are vulnerable to land-use change. We surveyed 41 wood-pastures from Southern Transylvania and counted the old oaks in them. We then related the number of old oaks from these wood-pastures to a set of local and landscape level variables related to wood-pastures. We found 490 old oaks in 25 wood-pastures. The number of old oaks was positively related to the size of the wood-pasture and the amount of pasture and forest around it (500 m buffer), and negatively related to the proximity of the village. Furthermore, we found a significant interaction between the effects of sheepfolds in the wood-pasture and the size of the wood-pasture on the number of old trees, indicating a negative influence of sheepfolds on the number of old trees in smaller sized wood-pastures. There is an increasing risk for losing old trees in the traditional cultural landscapes due to the lack of formal recognition of these trees. Therefore, while presenting the positive example of local initiatives and citizen science, we argue for an urgent development and implementation of conservation policies along with education strategies targeting the old trees and rural communities from the changing traditional cultural landscapes of Eastern Europe.


Asunto(s)
Agricultura , Ambiente , Dispersión de las Plantas , Quercus/fisiología , Cambio Social , Rumanía , Árboles/fisiología
9.
PLoS One ; 11(1): e0146977, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-26760300

RESUMEN

The article reports the radiocarbon investigation of Anzapalivoro, the largest za baobab (Adansonia za) specimen of Madagascar and of another za, namely the Big cistern baobab. Several wood samples collected from the large inner cavity and from the outer part/exterior of the tree were investigated by AMS (accelerator mass spectrometry) radiocarbon dating. For samples collected from the cavity walls, the age values increase with the distance into the wood up to a point of maximum age, after which the values decrease toward the outer part. This anomaly of age sequences indicates that the inner cavity of Anzapalivoro is a false cavity, practically an empty space between several fused stems disposed in a ring-shaped structure. The radiocarbon date of the oldest sample was 780 ± 30 bp, which corresponds to a calibrated age of around 735 yr. Dating results indicate that Anzapalivoro has a closed ring-shaped structure, which consists of 5 fused stems that close a false cavity. The oldest part of the biggest za baobab has a calculated age of 900 years. We also disclose results of the investigation of a second za baobab, the Big cistern baobab, which was hollowed out for water storage. This specimen, which consists of 4 fused stems, was found to be around 260 years old.


Asunto(s)
Adansonia , Espectrometría de Masas/métodos , Datación Radiométrica/métodos , Calibración , Ecología , Bosques , Geografía , Madagascar , Factores de Tiempo , Árboles , Madera
10.
PLoS One ; 10(11): e0142282, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26566029

RESUMEN

Ice ages within Europe forced many species to retreat to refugia, of which three major biogeographic basic types can be distinguished: "Mediterranean", "Continental" and "Alpine / Arctic" species. However, this classification often fails to explain the complex phylogeography of European species with a wide range of latitudinal and altitudinal distribution. Hence, we tested for the possibility that all three mentioned faunal elements are represented within one species. Our data was obtained by scoring 1,307 Euphydryas aurinia individuals (46 European locations) for 17 allozyme loci, and sequencing a subset of 492 individuals (21 sites) for a 626 base pairs COI fragment. Genetic diversity indices, F statistics, hierarchical analyses of molecular variance, individual-based clustering, and networks were used to explore the phylogeographic patterns. The COI fragment represented 18 haplotypes showing a strong geographic structure. All but one allozyme loci analysed were polymorphic with a mean FST of 0.20, supporting a pronounced among population structure. Interpretation of both genetic marker systems, using several analytical tools, calls for the recognition of twelve genetic groups. These analyses consistently distinguished different groups in Iberia (2), Italy, Provence, Alps (3), Slovenia, Carpathian Basin, the lowlands of West and Central Europe as well as Estonia, often with considerable additional substructures. The genetic data strongly support the hypothesis that E. aurinia survived the last glaciation in Mediterranean, extra-Mediterranean and perialpine refugia. It is thus a rare example of a model organism that combines attributes of faunal elements from all three of these sources. The observed differences between allozymes and mtDNA most likely result from recent introgression of mtDNA into nuclear allozyme groups. Our results indicate discrepancies with the morphologically-based subspecies models, underlining the need to revise the current taxonomy.


Asunto(s)
Mariposas Diurnas/genética , Especies en Peligro de Extinción , Variación Genética , Animales , ADN Mitocondrial/genética , Europa (Continente) , Haplotipos , Filogenia , Filogeografía
11.
PLoS One ; 9(7): e103256, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25058307

RESUMEN

European farmland biodiversity is declining due to land use changes towards agricultural intensification or abandonment. Some Eastern European farming systems have sustained traditional forms of use, resulting in high levels of biodiversity. However, global markets and international policies now imply rapid and major changes to these systems. To effectively protect farmland biodiversity, understanding landscape features which underpin species diversity is crucial. Focusing on butterflies, we addressed this question for a cultural-historic landscape in Southern Transylvania, Romania. Following a natural experiment, we randomly selected 120 survey sites in farmland, 60 each in grassland and arable land. We surveyed butterfly species richness and abundance by walking transects with four repeats in summer 2012. We analysed species composition using Detrended Correspondence Analysis. We modelled species richness, richness of functional groups, and abundance of selected species in response to topography, woody vegetation cover and heterogeneity at three spatial scales, using generalised linear mixed effects models. Species composition widely overlapped in grassland and arable land. Composition changed along gradients of heterogeneity at local and context scales, and of woody vegetation cover at context and landscape scales. The effect of local heterogeneity on species richness was positive in arable land, but negative in grassland. Plant species richness, and structural and topographic conditions at multiple scales explained species richness, richness of functional groups and species abundances. Our study revealed high conservation value of both grassland and arable land in low-intensity Eastern European farmland. Besides grassland, also heterogeneous arable land provides important habitat for butterflies. While butterfly diversity in arable land benefits from heterogeneity by small-scale structures, grasslands should be protected from fragmentation to provide sufficiently large areas for butterflies. These findings have important implications for EU agricultural and conservation policy. Most importantly, conservation management needs to consider entire landscapes, and implement appropriate measures at multiple spatial scales.


Asunto(s)
Agricultura/métodos , Biodiversidad , Mariposas Diurnas , Conservación de los Recursos Naturales/métodos , Animales , Mariposas Diurnas/clasificación , Ecosistema , Pradera , Dinámica Poblacional , Rumanía , Estaciones del Año
12.
PLoS One ; 8(4): e61185, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23593425

RESUMEN

Classical glacial refugia such as the southern European peninsulas were important for species survival during glacial periods and acted as sources of post-glacial colonisation processes. Only recently, some studies have provided evidence for glacial refugia north of the southern European peninsulas. In the present study, we combined species distribution models (SDMs) with phylogeographic analyses (using mitochondrial DNA = mtDNA) to investigate if the cold-adapted, stenotopic and flightless ground beetle species, Carabus irregularis, survived the Last Glacial Maximum (LGM) in classical and/or other refugia. SDMs (for both a western European and for a Carpathian subgroup) were calculated with MAXENT on the basis of 645 species records to predict current and past distribution patterns. Two mtDNA loci (CO1 and ND5, concatenated sequence length: 1785 bp) were analyzed from 91 C. irregularis specimens to reconstruct the phylogeography of Central and eastern European populations and to estimate divergence times of the given lineages. Strong intra-specific genetic differentiation (inter-clade ΦST values ranged from 0.92 to 0.99) implied long-term isolation of major clades and subsclades. The high divergence between the nominate subspecies and the Carpathian subspecies C. i. montandoni points to two independent species rather than subspecies (K-2P distance 0.042 ± 0.004; supposed divergence of the maternal lineages dated back 1.6 to 2.5 million years BP) differing not only morphologically but also genetically and ecologically from each other. The SDMs also inferred classical as well as other refugia for C. irregularis, especially north of the Alps, in southeastern Europe and in the Carpathians. The coincidences between the results of both methods confirm the assumption of multiple glacial refugia for the studied species and the usefulness of combining methodological approaches for the understanding of the history of low-dispersal insect species.


Asunto(s)
Escarabajos/genética , ADN Mitocondrial , Animales , Biodiversidad , Escarabajos/clasificación , Europa (Continente) , Evolución Molecular , Variación Genética , Haplotipos , Filogenia , Filogeografía , Dinámica Poblacional
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...