Home About us Contact
|
Home About us Contact | ||
|
|
||
Refuge Areas (refuge + area)
Selected AbstractsPhytogeographical evidence for post-glacial dispersal limitation of European beech forest speciesECOGRAPHY, Issue 6 2009Wolfgang Willner The post-glacial migration of European beech Fagus sylvatica has been addressed by many studies using either genetic or fossil data or a combination of both. In contrast to this, only little is known about the migration history of beech forest understorey species. In a review of phytosociological literature, we identified 110 plant species which are closely associated with beech forest. We divided the distribution range of European beech forests into 40 geographical regions, and the presence or absence of each species was recorded for each region. We compared overall species numbers per region and numbers of narrow-range species (species present in <10 regions). A multiple regression model was used to test for the explanatory value of three potential diversity controls: range in elevation, soil type diversity, and distance to the nearest potential refuge area. A hierarchical cluster analysis of the narrow-range species was performed. The frequency of range sizes shows a U-shaped distribution, with 42 species occurring in <10 regions. The highest number of beech forest species is found in the southern Alps and adjacent regions, and species numbers decrease with increasing distance from these regions. With only narrow-range species taken into consideration, secondary maxima are found in Spain, the southern Apennines, the Carpathians, and Greece. Distance to the nearest potential refuge area is the strongest predictor of beech forest species richness, while altitudinal range and soil type diversity had little or no predictive value. The clusters of narrow-range species are in good concordance with the glacial refuge areas of beech and other temperate tree species as estimated in recent studies. These findings support the hypothesis that the distribution of many beech forest species is limited by post-glacial dispersal rather than by their environmental requirements. [source] Role of Genetic Refuges in the Restoration of Native Gene Pools of Brown TroutCONSERVATION BIOLOGY, Issue 4 2009ROSA M. ARAGUAS introgresión de piscifactoría; pautas de manejo; acervos génicas nativas; refugios genéticos; repoblación de peces Abstract:,Captive-bred animals derived from native, alien, or hybrid stocks are often released in large numbers in natural settings with the intention of augmenting harvests. In brown trout (Salmo trutta), stocking with hatchery-reared non-native fish has been the main management strategy used to maintain or improve depleted wild brown trout populations in Iberian and other Mediterranean regions. This measure has become a serious threat to the conservation of native genetic diversity, mainly due to introgressive hybridization. Aware of this risk, the agency responsible for management of brown trout in the eastern Pyrenees (Spain) created "brown trout genetic refuges" to preserve the integrity of brown trout gene pools in this region. Within refuge areas, the prerefuge status with respect to fishing activities has been maintained, but hatchery releases have been banned completely. We evaluated this management strategy through a comparison of the stocking impact on native populations that accounted for stocking histories before and after refuge designations and fishing activities. In particular we examined the relevant scientific, cultural, and political challenges encountered. Despite agency willingness to change fishery policies to balance exploitation and conservation, acceptance of these new policies by anglers and genetic monitoring of refuge populations should also be considered. To improve management supported by genetic refuges, we suggest focusing on areas where the public is more receptive, considering the situation of local native diversity, and monitoring of adjacent introgressed populations. We recommend the use of directional supportive breeding only when a population really needs to be enhanced. In any case, management strategies should be developed to allow for protection within the context of human use. Resumen:,Animales criados en cautiverio derivados de individuos nativos, exóticos o híbridos a menudo son liberados en grandes cantidades en ambientes naturales con la intención de incrementar su explotación. En la trucha común (Salmo trutta), la repoblación con peces no nativos criados en granjas ha sido la principal estrategia de manejo utilizada para mantener o mejorar poblaciones naturales de trucha común en la Peninsula Ibérica y otras regiones Mediterráneas. Esta medida se ha convertido en una seria amenaza para la conservación de la diversidad genética nativa, debido principalmente a la hibridación introgresiva. Consciente de este riesgo, la agencia responsable del manejo de la trucha común en los Pirineos orientales (España) creó"refugios genéticos de trucha común" para preservar la integridad de las acervos genéticos de trucha común en esta región. Dentro de las áreas de refugio, se ha mantenido el estatus previo al refugio con respecto a las actividades pesqueras pero las liberaciones de peces de piscifactoría han sido completamente prohibidas. Evaluamos esta estrategia de manejo mediante la comparación del impacto de la repoblación sobre las poblaciones nativas que registraron historias de repoblación antes y después de la designación de refugios y de actividades pesqueras. En particular, examinamos los significativos retos científicos, culturales y políticos que encontramos. A pesar de la disponibilidad de la agencia para cambiar las políticas de pesca hacia un equilibrio entre la explotación y la conservación, también se debe considerar la aceptación de estas nuevas políticas por los pescadores y el monitoreo genético de las poblaciones en los refugios. Para mejorar el manejo en los refugios genéticos sugerimos centrarse en las áreas donde el público es más receptivo, considerando la situación de la diversidad nativa local y el monitoreo de las poblaciones introgresadas adyacentes. Recomendamos la utilización de la cría de apoyo direccional solo cuando una población realmente requiera ser mejorada. En cualquier caso, se deberían desarrollar estrategias de manejo para permitir la protección en el contexto del uso por el hombre. [source] Past and present potential distribution of the Iberian Abies species: a phytogeographic approach using fossil pollen data and species distribution modelsDIVERSITY AND DISTRIBUTIONS, Issue 2 2010Francisca Alba-Sánchez Abstract Aim, Quaternary palaeopalynological records collected throughout the Iberian Peninsula and species distribution models (SDMs) were integrated to gain a better understanding of the historical biogeography of the Iberian Abies species (i.e. Abies pinsapo and Abies alba). We hypothesize that SDMs and Abies palaeorecords are closely correlated, assuming a certain stasis in climatic and topographic ecological niche dimensions. In addition, the modelling results were used to assign the fossil records to A. alba or A. pinsapo, to identify environmental variables affecting their distribution, and to evaluate the ecological segregation between the two taxa. Location, The Iberian Peninsula. Methods, For the estimation of past Abies distributions, a hindcasting process was used. Abies pinsapo and A. alba were modelled individually, first calibrating the model for their current distributions in relation to the present climate, and then projecting it into the past,the last glacial maximum (LGM) and the Middle Holocene periods,in relation to palaeoclimate simulations. The resulting models were compared with Iberian-wide fossil pollen records to detect areas of overlap. Results, The overlap observed between past Abies refugia,inferred from fossil pollen records,and the SDMs helped to construct the Quaternary distribution of the Iberian Abies species. SDMs yielded two well-differentiated potential distributions: A. pinsapo throughout the Baetic mountain Range and A. alba along the Pyrenees and Cantabrian Range. These results propose that the two taxa remained isolated throughout the Quaternary, indicating a significant geographical and ecological segregation. In addition, no significant differences were detected comparing the three projections (present-day, Mid-Holocene and LGM), suggesting a relative climate stasis in the refuge areas during the Quaternary. Main conclusions, Our results confirm that SDM projections can provide a useful complement to palaeoecological studies, offering a less subjective and spatially explicit hypothesis concerning past geographic patterns of Iberian Abies species. The integration of ecological-niche characteristics from known occurrences of Abies species in conjunction with palaeoecological studies could constitute a suitable tool to define appropriate areas in which to focus proactive conservation strategies. [source] Phytogeographical evidence for post-glacial dispersal limitation of European beech forest speciesECOGRAPHY, Issue 6 2009Wolfgang Willner The post-glacial migration of European beech Fagus sylvatica has been addressed by many studies using either genetic or fossil data or a combination of both. In contrast to this, only little is known about the migration history of beech forest understorey species. In a review of phytosociological literature, we identified 110 plant species which are closely associated with beech forest. We divided the distribution range of European beech forests into 40 geographical regions, and the presence or absence of each species was recorded for each region. We compared overall species numbers per region and numbers of narrow-range species (species present in <10 regions). A multiple regression model was used to test for the explanatory value of three potential diversity controls: range in elevation, soil type diversity, and distance to the nearest potential refuge area. A hierarchical cluster analysis of the narrow-range species was performed. The frequency of range sizes shows a U-shaped distribution, with 42 species occurring in <10 regions. The highest number of beech forest species is found in the southern Alps and adjacent regions, and species numbers decrease with increasing distance from these regions. With only narrow-range species taken into consideration, secondary maxima are found in Spain, the southern Apennines, the Carpathians, and Greece. Distance to the nearest potential refuge area is the strongest predictor of beech forest species richness, while altitudinal range and soil type diversity had little or no predictive value. The clusters of narrow-range species are in good concordance with the glacial refuge areas of beech and other temperate tree species as estimated in recent studies. These findings support the hypothesis that the distribution of many beech forest species is limited by post-glacial dispersal rather than by their environmental requirements. [source] A biogeographical analysis of the European Atlantic lowland heathlandsJOURNAL OF VEGETATION SCIENCE, Issue 5 2010Javier Loidi Abstract Questions: What is the climatic envelope of European Atlantic heathlands and the relationship between their floristic geographical variability and climatic parameters? Are the biogeographic patterns extracted from genuine heath plants comparable to those extracted from the accompanying flora? To what extent does the species composition extracted from phytosociological data support the current theory of refuge areas of heath vegetation in southern Atlantic Europe during the Pleistocene ice ages? Location: Atlantic Europe and NW Morocco. Methods: The geographical territory in which Atlantic heathlands occur was divided into 23 sectors following geographic and chorological criteria. A presence,absence table with 333 taxa was then constructed with the available phytosociological data. The taxa were classified into different groups according to their phytosociological affinity. Several types of numerical analysis were performed with this matrix and the climatic data obtained from meteorological sources. Results: Heathlands require a humid and oceanic climate and are limited by cold temperatures in the north and by summer droughts in the south. The highest floristic richness of this vegetation type is found in NW Iberia. Ordinations indicate a strong correlation between floristic composition of biogeographic sector and summer drought (Ios) and thermicity (It). Conclusions: The main climatic factors determining lowland heathland floristic distribution are thermicity and summer drought. The current optimal conditions for heath flora in NW Iberia suggest that there were southern refuges during the Pleistocene ice ages from which northward expansion has taken place. [source] Comparative phylogeography of four Apodemus species (Mammalia: Rodentia) in the Asian Far East: evidence of Quaternary climatic changes in their genetic structureBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2010HÉLA SAKKA The phylogeography of four Apodemus species (Apodemus agrarius, Apodemus peninsulae, Apodemus latronum, and Apodemus draco) was studied in the Far East of Asia, based on sequences of the mitochondrial DNA cytochrome b gene. The results obtained show the existence of many different genetic lineages within the studied Apodemus species, suggesting the isolation and differentiation of populations in multiple refuge areas. Higher genetic diversities in some regions such as Yunnan, Sichuan (China), and eastern Russia suggest these areas are potential refuges for these species. The existence of such complex genetic structures could be linked to the presence of many biogeographic barriers (Himalaya Mountains, Tien-shan Mountains, Altai Mountains, Tibetan Plateau, Gobi desert, Yunnan Guizhou Plateau, Dzungaria basin, and others) in these regions, which were probably reinforced during the Quaternary climate changes. These barriers also played an important role concerning the low dispersal abilities of the two studied Apodemus species adapted to forest habitats (A. latronum and A. draco) with respect to colonizing regions other than China. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 797,821. [source] | ||||||||||