863 resultados para Biodiversity hotspot
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The eastern Mediterranean is a hotspot of biological invasions. Numerous species of Indo-pacific origin have colonized the Mediterranean in recent times, including tropical symbiont-bearing foraminifera. Among these is the species Pararotalia calcariformata. Unlike other invasive foraminifera, this species has been discovered only two decades ago and is restricted to the eastern Mediterranean coast. Combining ecological, genetic and physiological observations, we attempt to explain the recent invasion of this species in the Mediterranean Sea. Using morphological and genetic data, we confirm the species attribution to P. calcariformata McCulloch 1977 and identify its symbionts as a consortium of diatom species dominated by Minutocellus polymorphus. We document photosynthetic activity of its endosymbionts using Pulse Amplitude Modulated Fluorometry and test the effects of elevated temperatures on growth rates of asexual offspring. The culturing of asexual offspring for 120 days shows a 30-day period of rapid growth followed by a period of slower growth. A subsequent 48-day temperature sensitivity experiment indicates a similar developmental pathway and high growth rate at 28°C, whereas an almost complete inhibition of growth was observed at 20°C and 35°C. This indicates that the offspring of this species may have lower tolerance to cold temperatures than what would be expected for species native to the Mediterranean. We expand this hypothesis by applying a Species Distribution Model (SDM) based on modern occurrences in the Mediterranean using three environmental variables: irradiance, turbidity and yearly minimum temperature. The model reproduces the observed restricted distribution and indicates that the range of the species will drastically expand westwards under future global change scenarios. We conclude that P. calcariformata established a population in the Levant because of the recent warming in the region. In line with observations from other groups of organisms, our results indicate that continued warming of the eastern Mediterranean will facilitate the invasion of more tropical marine taxa into the Mediterranean, disturbing local biodiversity and ecosystem structure.
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The injection of gas into sub-seabed aquifers may lead to the displacement of hypoxic and hypersaline fluids (reservoir formation water) major environmental risk. To investigate this risk, the impact of formation water release on the macrofaunal community in a mesocosm experiment at Solbergstrand was conducted. 20 boxcores were exposed to 4 treatments (high salinity, hypoxic, mixed and tidal) during two weeks. The abundance of macrofauna was quantified for each treatment and richness, eveness and biodiversity indices calculated. The data are reported in this dataset.
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The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. The present data set provides biodiversity context to all samples from the Tara Oceans Expedition (2009-2013), including various diversity indexes calculated for the sampling location using satellite and model climatologies (Darwin project, Physat) and results from the sequencing of Tara Oceans samples.
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The effect of biodiversity on the ability of parasites to infect their host and cause disease (i.e. disease risk) is a major question in pathology, which is central to understand the emergence of infectious diseases, and to develop strategies for their management. Two hypotheses, which can be considered as extremes of a continuum, relate biodiversity to disease risk: One states that biodiversity is positively correlated with disease risk (Amplification Effect), and the second predicts a negative correlation between biodiversity and disease risk (Dilution Effect). Which of them applies better to different host-parasite systems is still a source of debate, due to limited experimental or empirical data. This is especially the case for viral diseases of plants. To address this subject, we have monitored for three years the prevalence of several viruses, and virus-associated symptoms, in populations of wild pepper (chiltepin) under different levels of human management. For each population, we also measured the habitat species diversity, host plant genetic diversity and host plant density. Results indicate that disease and infection risk increased with the level of human management, which was associated with decreased species diversity and host genetic diversity, and with increased host plant density. Importantly, species diversity of the habitat was the primary predictor of disease risk for wild chiltepin populations. This changed in managed populations where host genetic diversity was the primary predictor. Host density was generally a poorer predictor of disease and infection risk. These results support the dilution effect hypothesis, and underline the relevance of different ecological factors in determining disease/infection risk in host plant populations under different levels of anthropic influence. These results are relevant for managing plant diseases and for establishing conservation policies for endangered plant species.
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Cloud forests are unusual and fragile habitats, being one of the least studied and least understood ecosystems. The tropical Andean dominion is considered one of the most significant places in the world as rega rds biological diversity, with a very high level of endemism. The biodiversity was analysed in an isolated remnant area of a tropical montane cloud forest known as the ?Bosque de Neblina de Cuyas?, in the North of the Peruvian Andean range. Composition, structure and dead wood were measured or estimated. The values obtained were compared with other cloud forests. The study revealed a high level of forest biodiversity, although the level of biodiversity differs from one area to another: in the inner areas, where human pressure is almost inexistent, the biodiversity values increase. The high species richness and the low dominance among species bear testimony to this montane cloud forest as a real enclave of biodiversity.
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El ser humano nunca ha tenido una capacidad semejante a la actual para alterar el medio en el que vive. A través fundamentalmente de cambios en el uso del hábitat, alteración de los ciclos biogeoquímicos, cambio climático y presencia de especies invasoras, la tasa de extinción de especies se ha acelerado enormemente. Al crecer más rápido la población humana dentro de las áreas en las que se concentra una mayor biodiversidad (biodiversity hotspots), las tasas de transformación son mayores, por lo que dicha biodiversidad se encuentra más amenazada. Entre los principales 25 biodiversity hotspots globales se encuentra la cuenca mediterránea. Las afecciones a la biodiversidad hacen por tanto que en dicha cuenca mediterránea sea necesario poner en práctica iniciativas innovadoras para su conservación. Pero además de una cuidadosa selección, es necesario el seguimiento y la evaluación de la eficacia y la eficienca de dichas medidas, para comprobar su idoneidad y mejorarlas cuando sea posible. Esta es la tarea de la ingeniería de la conservación. Esta Memoria busca analizar y proponer mejoras en cuatro acciones experimentales de conservación de la biodiversidad que tienen un marco común, la conservación de especies subrogadas del monte mediterráneo. En concreto de cinco especies amenazadas: conejo de monte (Oryctolagus cuniculus, especie llave), águila imperial ibérica (Aquila adalberti), águila perdicera (Aquila fasciata), cigüeña negra (Ciconia nigra) y lince ibérico (Lynx pardinus), todas ellas especies paraguas y bandera. Casi todas estas especies se enfrentan a amenazas comunes, como son la pérdida de la calidad del hábitat, la mortalidad de origen humano, la escasez de alimento o la falta de eficiencia en las técnicas de seguimiento. Las acciones destinadas a revertir o minimizar estas amenazas han tenido un marco geográfico y ecológico común, 49 fincas privadas de monte mediterráneo situadas en 9 espacios de la Red Natura 2000 del centro-occidental peninsular, en las que se ha podido trabajar merced a acuerdos de custodia del territorio. Dichas actividades han sido financiadas casi por completo con cargo a fondos LIFE Naturaleza de la Comisión Europea. El presente documento contribuye a aportar el conocimiento científico imprescindible para mejorar la eficacia y eficiencia de las medidas técnicas de gestión y conservación: la ingeniería de la conservación. Como resultados más relevantes se pueden citar que la selección del conejo de las zonas sembradas aumenta con la presencia tanto de isletas de matorral como de refugios y resulta inferior en las zonas de matorral más cerrado; que la electrocución es una de las principales causas de mortalidad de las rapaces amenazadas, así como que se ha detectado que la mortalidad se concentra en determinadas zonas que deben ser prioritarias para su corrección y que éstas deben pasar por las modificaciones estructurales; que la selección de zonas de alimentación por parte de la cigüeña negra se ve afectada por numerosos factores y que una adecuada ubicación y gestión de las charcas para ganadería y caza mayor puede favorecer no sólo la alimentación de esta especie, sino suponer un lugar de cría para diversas especies de anfibios y peces autóctonos, en franco declive; finalmente, hay que destacar que la mejora en el seguimiento de las poblaciones de lince ibérico pasa por la incorporación de métodos de seguimiento novedosos, como las cámaras infrarrojas en letrinas, dada la capacidad de aprendizaje de la especie. Abstract Nowadays the human being has reached its top ability to exchange its environment. Mainly through habitat change, altering biogeochemical cycles, climatic change and alien species, global extinction rate has increased dramatically. Population increases faster in biodiversity hotspots, thus change rates are higher. Mediterranean basin is included within the 25 most valuable biodiversity hotspots. Affections on biodiversity turns necessary to develop innovative actions to maintain the most threatened species in this hotspot. But further than a careful selection and implementarion, survey and evaluation of those practices is necessary to check its suitability. Those are actions for the conservation engineering. This Memory looks for to analyze and to put forward improvements in four experimental biodiversity conservation actions with a common framework: conservation of surrogate Mediterranean species. Those actions were specifically directed to five threatened species: the European wild rabbit (Oryctolagus cuniculus, key species), Spanish imperial eagle (Aquila adalberti) and Bonelli’s eagle (Aquila fasciata, both of the umbrella and flagship species), black stork (Ciconia nigra, umbrella and flagship species) and the Iberian lynx (Lynx pardinus, umbrella and flagship species). Those species have common threats: habitat loss, maninduced mortality, food shortening and lack of surveying efficiency. Actions aimed to minimize those threats also had a common geographical frame: 49 privately owned states within 9 Natura 2000 areas in Southwestern Spain. Actions were developed through lands tewardship agreements, and were even wholly undertaken through European Commision LIFE’s fund. This document contributes to develop cientific knowledge necessary for increasing efficacy and efficiency for implementing technical measures devoted to conservation, the conservation engineering. One of the most outstanding result might be the necessity of including bushy islets or rabbit shelter within sowings when enhacing rabbit populations is the goal. Electrocution is one of the commonest man-induced death causes for raptors, especially for the threatened ones. Areas of concentration of this mortality have been detected, and when mitigation measures have been evaluated, only structural modifications had results. The black stork’s selection of feeding areas is influenced by several factors. An adequate location and management of livestock’s ponds can favour not only this species, but also creating new breeding places for amphibians and indigenous fish species, most of them in a sharp decline. Finally, improving the survey of the Iberian lynx might be achieved through implementing newly developed surveying systems, such as the infrared cameras in latrines.
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Improved management of nitrogen (N) in agriculture is necessary to achieve a sustainable balance between the production of food and other biomass, and the unwanted effects of N on water pollution, greenhouse gas emissions, biodiversity deterioration and human health. To analyse farm N-losses and the complex interactions within farming systems, efficient methods for identifying emissions hotspots and evaluating mitigation measures are therefore needed. The present paper aims to fill this gap at the farm and landscape scales. Six agricultural landscapes in Poland (PL), the Netherlands (NL), France (FR), Italy (IT), Scotland (UK) and Denmark (DK) were studied, and a common method was developed for undertaking farm inventories and the derivation of farm N balances, N surpluses and for evaluating uncertainty for the 222 farms and 11 440 ha of farmland included in the study. In all landscapes, a large variation in the farm N surplus was found, and thereby a large potential for reductions. The highest average N surpluses were found in the most livestock-intensive landscapes of IT, FR, and NL; on average 202 ± 28, 179 ± 63 and 178 ± 20 kg N ha−1 yr−1, respectively. All landscapes showed hotspots, especially from livestock farms, including a special UK case with large-scale landless poultry farming. Overall, the average N surplus from the land-based UK farms dominated by extensive sheep and cattle grazing was only 31 ± 10 kg N ha−1 yr−1, but was similar to the N surplus of PL and DK (122 ± 20 and 146 ± 55 kg N ha−1 yr−1, respectively) when landless poultry farming was included. We found farm N balances to be a useful indicator for N losses and the potential for improving N management. Significant correlations to N surplus were found, both with ammonia air concentrations and nitrate concentrations in soils and groundwater, measured during the period of N management data collection in the landscapes from 2007–2009. This indicates that farm N surpluses may be used as an independent dataset for validation of measured and modelled N emissions in agricultural landscapes. No significant correlation was found with N measured in surface waters, probably because of spatial and temporal variations in groundwater buffering and biogeochemical reactions affecting N flows from farm to surface waters. A case study of the development in N surplus from the landscape in DK from 1998–2008 showed a 22% reduction related to measures targeted at N emissions from livestock farms. Based on the large differences in N surplus between average N management farms and the most modern and N-efficient farms, it was concluded that additional N-surplus reductions of 25–50%, as compared to the present level, were realistic in all landscapes. The implemented N-surplus method was thus effective for comparing and synthesizing results on farm N emissions and the potentials of mitigation options. It is recommended for use in combination with other methods for the assessment of landscape N emissions and farm N efficiency, including more detailed N source and N sink hotspot mapping, measurements and modelling.
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Presentamos en una sesión dedicada al proyecto ROBIN: Session No. 101: Whole system approaches for managing land-use change to deliver multiple benefits from biodiversity in tropical forest landcapes (Chairs: Terry Parr, Michael Schmidt, Kirsten Thonicke - Theme 3)
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Aflatoxin B1 (AFB1) is a potent human carcinogen implicated in the etiology of hepatocellular carcinoma. Upon metabolic activation to the reactive epoxide, AFB1 forms DNA adducts primarily at the N7 position of guanines. To elucidate more fully the molecular mechanism of AFB1-induced mutagenesis, an intercalation inhibitor was designed to probe the effects of intercalation by AFB1 epoxide on its reaction with DNA. DNA duplexes were prepared consisting of a target strand containing multiple potentially reactive guanines and a nontarget strand containing a cis-syn thymidine-benzofuran photoproduct. Because the covalently linked benzofuran moiety physically occupies an intercalation site, we reasoned that such a site would be rendered inaccessible to AFB1 epoxide. By strategic positioning of this intercalation inhibitor in the intercalation site 5′ to a specific guanine, the adduct yield at that site was greatly diminished, indicating that intercalation by AFB1 epoxide contributes favorably to adduct formation. Using this approach it has been possible to simplify the production of site-specifically modified oligonucleotides containing AFB1 adducts in the sequence context of a p53 mutational hotspot. Moreover, we report herein isolation of site-specifically AFB1-modified oligonucleotides in sequences containing multiple guanines. Use of intercalation inhibitors will facilitate both investigation of the ability of other carcinogens to intercalate into DNA and the synthesis of specific carcinogen-DNA adducts.
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Peer reviewed