To maintain biodiversity in managed forests we must understand the patterns and processes that regulate the occurrence and dynamics of species in undisturbed ecosystems. We compared biomass and species composition of canopy lichens on 180 lower branches of Norway spruce (Picea abies) in three pairs of old‐growth and managed (selectively logged) stands in northern Sweden (30 branches per stand). The purpose was to evaluate the effect of substrate quality (branch characteristics) on patterns of lichen biomass for two different growth forms (foliose and fruticose). Old‐growth stands had six times higher lichen mass per spruce branch, and two times higher expressed as percentage of branch mass, compared to mature stands of managed forest. Lichen mass was strongly related to mass, diameter, and age of branches. Fruticose, pendulous species (Alectoria sarmentosa and Bryoria spp.) were highly sensitive to forest practices. In contrast, type of forest had no significant effect on foliose species. Species number per stand was the same (15 species) in both types of forest, but there were marked differences in the relative abundance of different lichen groups. Results suggest that limited amount of substrate (i.e., small branches) available to lichens, and young branches, providing only a short time for lichen colonization and growth, are important factors limiting epiphytic lichen abundance in managed forests. Conversion of old‐growth forest into young, managed stands will lead to a significant reduction in epiphytic lichen mass. This in turn may probably affect nutrient cycling in forests and has negative consequences for animals that utilize canopy lichens as food, shelter, or nesting material.
Dengue fever is a mosquito-borne viral disease estimated to cause about 230 million infections worldwide every year, of which 25,000 are fatal. Global incidence has risen rapidly in recent decades with some 3.6 billion people, over half of the world's population, now at risk, mainly in urban centres of the tropics and subtropics. Demographic and societal changes, in particular urbanization, globalization, and increased international travel, are major contributors to the rise in incidence and geographic expansion of dengue infections. Major research gaps continue to hamper the control of dengue. The European Commission launched a call under the 7th Framework Programme with the title of ‘Comprehensive control of Dengue fever under changing climatic conditions’. Fourteen partners from several countries in Europe, Asia, and South America formed a consortium named ‘DengueTools’ to respond to the call to achieve better diagnosis, surveillance, prevention, and predictive models and improve our understanding of the spread of dengue to previously uninfected regions (including Europe) in the context of globalization and climate change. The consortium comprises 12 work packages to address a set of research questions in three areas: Research area 1: Develop a comprehensive early warning and surveillance system that has predictive capability for epidemic dengue and benefits from novel tools for laboratory diagnosis and vector monitoring. Research area 2: Develop novel strategies to prevent dengue in children. Research area 3: Understand and predict the risk of global spread of dengue, in particular the risk of introduction and establishment in Europe, within the context of parameters of vectorial capacity, global mobility, and climate change. In this paper, we report on the rationale and specific study objectives of ‘DengueTools’. DengueTools is funded under the Health theme of the Seventh Framework Programme of the European Community, Grant Agreement Number: 282589 Dengue Tools.
Increased amount of edge habitat is one of several important consequences of forest fragmentation. Consequently, we must understand the responses of plants and animals to edges to formulate adequate recommendations for conservation of biodiversity. Epiphytic lichens are a well-suited subject for a study of abiotic edge effects because they gain nutrients and water directly from the atmosphere. We present a temporal model of edge effects on lichens based on empirical data for the pendulous, fruticose species Alectoria sarmentosa . Ten high-contrast edges of different age between mature Picea abies forest and large clearcuts (10-260 ha) were studied in northwestern Sweden. Abundance of A. sarmentosa (mass on 1-m branch sections and maximum thallus length per tree) was estimated in the lower canopy in four 10 ϫ 50-m 2 plots located 5-100 m into the forest. The abundance of A. sarmentosa was markedly lower at the edge compared to the interior at 9 of 10 study sites. Lichen mass constituted 22% of that in the interior at young edges (0.5-2.5 years) and 55% at old edges (8-16 years). The length of A. sarmentosa was significantly affected by both distance from the edge and site location. Maximum edge effects extended 25-50 m into the forest at moderately exposed sites. The major factor reducing lichen abundance was physical damage by strong wind. Large, pendulous lichens such as A. sarmentosa are prone to thallus fragmentation. At older edges lichen abundance had recovered inside the edge (20-30 m), probably due to increased growth in response to increased irradiance. Our analysis supports the view that edge effects may be strongly dynamic over time and caused by the interaction of several factors. We conclude that epiphytic lichens have large potential as indicators of forest edge effects. Efectos de Borde en un Líquen Epífito en Bosques FragmentadosResumen: Una de las múltiples consecuencias importantes de la fragmentación de bosques es el incremento en la cantidad de borde en el hábitat. En consecuencia, debemos entender las respuestas de plantas y animales a los bordes para formular recomendaciones apropiadas para la conservación de la biodiversidad. Los líquenes epífitos son sujetos aptos para el estudio de efectos abióticos de borde, puesto que obtienen nutrientes y agua directamente de la atmósfera. Presentamos un modelo temporal de los efectos de borde en líquenes basado en datos empíricos de la especie Alectoria sarmentosa . Diez bordes de alto contraste y diferentes edades ubicados entre bosques maduros de Picea abies y clareos grandes (10-260 ha) fueron estudiados en Suiza noroccidental. La abundancia de A. sarmentosa (masa en secciones de rama de 1 m y longitud máxima de tallo por árbol) se estimó en el dosel bajo en cuatro áreas de 10 ϫ 50 m 2 localizados de 5-100 m dentro del bosque. La abundancia de A. sarmentosa fue marcadamente menor en los bordes comparando con el interior en 9 de 10 sitios de estudio. En los bordes jóvenes (0.5-2.5 años) la masa de líquen constituyó un 22% de lo observado en el interi...
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