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Local Biodiversity (local + biodiversity)
Selected AbstractsMotivations for the Restoration of EcosystemsCONSERVATION BIOLOGY, Issue 2 2006ANDRE F. CLEWELL cambio climático; capital natural; restauración ecológica Abstract:,The reasons ecosystems should be restored are numerous, disparate, generally understated, and commonly underappreciated. We offer a typology in which these reasons,or motivations,are ordered among five rationales: technocratic, biotic, heuristic, idealistic, and pragmatic. The technocratic rationale encompasses restoration that is conducted by government agencies or other large organizations to satisfy specific institutional missions and mandates. The biotic rationale for restoration is to recover lost aspects of local biodiversity. The heuristic rationale attempts to elicit or demonstrate ecological principles and biotic expressions. The idealistic rationale consists of personal and cultural expressions of concern or atonement for environmental degradation, reengagement with nature, and/or spiritual fulfillment. The pragmatic rationale seeks to recover or repair ecosystems for their capacity to provide a broad array of natural services and products upon which human economies depend and to counteract extremes in climate caused by ecosystem loss. We propose that technocratic restoration, as currently conceived and practiced, is too narrow in scope and should be broadened to include the pragmatic rationale whose overarching importance is just beginning to be recognized. We suggest that technocratic restoration is too authoritarian, that idealistic restoration is overly restricted by lack of administrative strengths, and that a melding of the two approaches would benefit both. Three recent examples are given of restoration that blends the technocratic, idealistic, and pragmatic rationales and demonstrates the potential for a more unified approach. The biotic and heuristic rationales can be satisfied within the contexts of the other rationales. Resumen:,Las razones por la que los ecosistemas deben ser restaurados son numerosas, dispares, generalmente poco sustentadas, y comúnmente poco apreciadas. Ofrecemos una tipología en la que estas razones,o motivaciones,son ordenadas entre cinco razonamientos: tecnocrático, biótico, heurístico, idealista y pragmático. El razonamiento tecnocrático se refiere a la restauración que es llevada a cabo por agencias gubernamentales u otras grandes organizaciones para satisfacer misiones y mandatos institucionales específicos. El razonamiento biótico de la restauración es la recuperación de aspectos perdidos de la biodiversidad local. El razonamiento heurístico intenta extraer o demostrar principios ecológicos y expresiones bióticas. El razonamiento idealista consiste de expresiones personales y culturales de la preocupación o reparación de la degradación ambiental, reencuentro con la naturaleza y/o cumplimiento espiritual. El razonamiento pragmático busca recuperar o reparar ecosistemas por su capacidad de proporcionar una amplia gama de servicios y productos naturales de la que dependen las economías humanas y para contrarrestar extremos en el clima causados por la pérdida de ecosistemas. Proponemos que la restauración tecnocrática, como se concibe y practica actualmente, es muy corta en su alcance y debiera ampliarse para incluir al razonamiento pragmático, cuya importancia apenas comienza a ser reconocida. Sugerimos que la restauración tecnocrática es demasiado autoritaria, que la restauración idealista esta muy restringida por la falta de fortalezas administrativas, y que una mezcla de los dos enfoques podría beneficiar a ambas. Proporcionamos tres ejemplos recientes de restauración que combinan los razonamientos tecnocrático, idealista y pragmático y demuestran el potencial para un enfoque más unificado. Los razonamientos biótico y heurístico pueden ser satisfechos en el contexto de los otros razonamientos. [source] Effects of Acer platanoides invasion on understory plant communities and tree regeneration in the northern Rocky MountainsECOGRAPHY, Issue 5 2005Kurt O. Reinhart Quantitative studies are necessary to determine whether invasive plant species displace natives and reduce local biodiversity, or if they increase local biodiversity. Here we describe the effects of invasion by Norway maple Acer platanoides on riparian plant communities and tree regeneration at two different scales (individual tree vs stand scales) in western Montana, USA, using both descriptive and experimental approaches. The three stands differed in community composition with the stand most dominated by A. platanoides invasion being more compositionally homogenous, and less species rich (,67%), species even (,40%), and diverse (,75%) than the two other stands. This sharp decrease in community richness and diversity of the highly invaded stand, relative to the other stands, corresponded with a 28-fold increase in A. platanoides seedlings and saplings. The dramatic difference between stand 1 vs 2 and 3 suggests that A. platanoides invasion is associated with a dramatic change in community composition and local loss of species diversity; however, other unaccounted for differences between stands may be the cause. These whole-stand correlations were corroborated by community patterns under individual A. platanoides trees in a stand with intermediate levels of patchy invasion. At the scale of individual A. platanoides canopies within a matrix of native trees, diversity and richness of species beneath solitary A. platanoides trees declined as the size of the trees increased. These decreases in native community properties corresponded with an increase in the density of A. platanoides seedlings. The effect of A. platanoides at the stand scale was more dramatic than at the individual canopy scale; however, at this smaller scale we only collected data from the stand with intermediate levels of invasion and not from the stand with high levels of invasion. Transplant experiments with tree seedlings demonstrated that A. platanoides seedlings performed better when grown beneath conspecific canopies than under natives, but Populus and Pinus seedlings performed better when grown beneath Populus canopies, the dominant native. Our results indicate that A. platanoides trees suppress most native species, including the regeneration of the natural canopy dominants, but facilitate conspecifics in their understories. [source] A novel genealogical approach to neutral biodiversity theoryECOLOGY LETTERS, Issue 3 2004Rampal S. Etienne Abstract Current neutral theory in community ecology views local biodiversity as a result of the interplay between speciation, extinction and immigration. Simulations and a mean-field approximation have been used to study this neutral theory. As simulations have limitations of convergence and the mean-field approximation ignores dependencies between species' abundances when applied to species-abundance data, there is still no final conclusion whether the neutral theory or the traditional lognormal model describes community structure best. We present a novel analytical framework, based on the genealogy of individuals in the local community, to overcome the problems of previous approaches, and show, using Bayesian statistics, that the lognormal model provides a slightly better fit to the species-abundance distribution of a much-discussed tropical tree community. A key feature of our approach is that it shows the tight link between genetic and species diversity, which creates important perspectives to future integration of evolutionary and community ecological theory. [source] Recovery of anuran community diversity following habitat replacementJOURNAL OF APPLIED ECOLOGY, Issue 1 2010David Lesbarrères Summary 1.,Recently habitat degradation, road construction and traffic have all increased with human populations, to the detriment of aquatic habitats and species. While numerous restoration programmes have been carried out, there is an urgent need to follow their success to better understand and compensate for the decline of amphibian populations. To this end, we followed the colonization success of an anuran community across multiple replacement ponds created to mitigate large-scale habitat disturbance. 2.,Following construction of a highway in western France, a restoration project was initiated in 1999 and the success of restoration efforts was monitored. The amphibian communities of eight ponds were surveyed before they were destroyed. Replacement ponds were created according to precise edaphic criteria, consistent with the old pond characteristics and taking into account the amphibian species present in each. The presence of amphibian species was recorded every year during the breeding period for 4 years following pond creation. 3.,Species richness initially declined following construction of the replacement ponds but generally returned to pre-construction levels. Species diversity followed the same pattern but took longer to reach the level of diversity recorded before construction. Pond surface area, depth and sun exposure were the most significant habitat characteristics explaining both amphibian species richness and diversity. Similarly, an increase in the number of vegetation strata was positively related to anuran species richness, indicating the need to maintain a heterogeneous landscape containing relatively large open wetland areas. 4.,Synthesis and applications. We highlight the species-specific dynamics of the colonization process, including an increase in the number of replacement ponds inhabited over time by some species and, in some cases, an increase in population size. Our work suggests that successful replacement ponds can be designed around simple habitat features, providing clear benefits for a range of amphibian species, which will have positive cascading effects on local biodiversity. However, consideration must also be given to the terrestrial buffer zone when management strategies are being planned. Finally, our study offers insight into the successful establishment of anuran communities over a relatively short time in restored or replacement aquatic environments. [source] Spider family composition and species richness patterns in two savannah habitats along the eastern coastal plain of AfricaAFRICAN JOURNAL OF ECOLOGY, Issue 2 2010Charles R. Haddad Abstract The spider faunas of two savannah reserves along the eastern coastal plain of Africa are compared. Species richness was higher in the tropical area, with 493 species (54 families) from Mkomazi Game Reserve, Tanzania. Species richness was also high in the subtropics, with a total of 431 species (46 families) recorded from Ndumo Game Reserve, South Africa. Spider community structure was remarkably similar in the two reserves, with Salticidae, Gnaphosidae, Thomisidae, Theridiidae and Araneidae the most species-rich families in both reserves. Eleven of the fourteen most species rich families were the same. A similar proportion of families were represented by singleton and doubleton species. A genus- and species-level comparison of ten spider families indicates that while there is considerable overlap in the generic composition of the reserves (Sorensen's Quotient of similarity: all >0.650 except Linyphiidae, 0.166; Corinnidae, 0.500) there is little overlap between the species occurring in the two sites (0.000,0.571), which was particularly evident in the more species-rich families. A comparison of diversity of 57 families in each reserve with the spider biodiversity in the two sub-regions suggests that local biodiversity is largely determined by regional biogeographical influences rather than local ecological factors. Résumé On compare ici les araignées de deux réserves de savane situées le long de la plaine côtière de l'est de l'Afrique. La richesse en espèces était plus grande dans la région tropicale, avec 493 espèces (54 familles) dénombrées dans la Mkomazi Game Reserve, en Tanzanie. La richesse en espèces était aussi élevée dans la région subtropicale, avec un total de 431 espèces (46 familles) rapportées dans la Ndumo Game Reserve, en Afrique du Sud. La structure de la communauté des araignées était remarquablement semblable dans les deux réserves, et les Salticidae, Gnaphosidae, Thomisidae, Theridiidae et les Araneidae étaient aux deux endroits les familles les plus riches en espèces. Onze des quatorze familles les plus riches en espèces étaient les mêmes. Une proportion semblable de familles n'étaient représentées que par des espèces singletons ou doubletons. Une comparaison de dix familles d'araignées au niveau du genre ou de l'espèce indique que, s'il existe un important chevauchement de la composition générique des deux réserves (quotient de similitude de Sorensen : tous > 0,650 à l'exception des Linyphiidae, 0,166, et des Corinnidae, 0,500), il y a peu de chevauchement entre les espèces qui vivent dans les deux sites (0,000,0,571), ce qui était particulièrement évident dans les familles les plus riches en espèces. Une comparaison de la diversité de 57 familles dans chaque réserve avec la biodiversité des araignées des deux sous-régions suggère que la biodiversité locale était largement déterminée par des influences biogéographiques régionales plutôt que par des facteurs écologiques locaux. [source] Green Footstep: A Tool for Evaluating a Building's Life-Cycle Carbon Footprint and Informing Carbon Decisions During the Building Design ProcessARCHITECTURAL DESIGN, Issue 3 2010Michael Bendewald Abstract The Green Footstep model provides a valuable set of metrics for ecodesign and masterplanning. Here Michael Bendewald and Victor Olgyay of the Rocky Mountain Institute (RMI), with Ken Yeang, describe the significance of this new online tool. In addition to supplying the basis for balancing the built environment's engineering systems, the Green Footstep enables efficiency with the use of renewable energy systems, such as photovoltaics (illustrated here). By presenting the critical case for increasing the percentage of new vegetation and trees in new developments, it enhances local biodiversity. Carbon emissions are offset from: on-site clearance of vegetation, the disturbance of the many constituents of the local ecosystem and the removal of organic rich soil by new construction. Copyright © 2010 John Wiley & Sons, Ltd. [source] Biological invasions in the Antarctic: extent, impacts and implicationsBIOLOGICAL REVIEWS, Issue 1 2005Yves Frenot ABSTRACT Alien microbes, fungi, plants and animals occur on most of the sub-Antarctic islands and some parts of the Antarctic continent. These have arrived over approximately the last two centuries, coincident with human activity in the region. Introduction routes have varied, but are largely associated with movement of people and cargo in connection with industrial, national scientific program and tourist operations. The large majority of aliens are European in origin. They have both direct and indirect impacts on the functioning of species-poor Antarctic ecosystems, in particular including substantial loss of local biodiversity and changes to ecosystem processes. With rapid climate change occurring in some parts of Antarctica, elevated numbers of introductions and enhanced success of colonization by aliens are likely, with consequent increases in impacts on ecosystems. Mitigation measures that will substantially reduce the risk of introductions to Antarctica and the sub-Antarctic must focus on reducing propagule loads on humans, and their food, cargo, and transport vessels. [source] Reduced-impact Logging has Little Effect on Temporal Activity of Frugivorous Bats (Chiroptera) in Lowland AmazoniaBIOTROPICA, Issue 3 2009Steven J. Presley ABSTRACT Reduced-impact logging (RIL) represents a viable option for sustainable use of Neotropical lowland forests while minimizing negative effects on local biodiversity. Many Neotropical bats of the family Phyllostomidae provide ecosystem services associated with pollination and seed dispersal that promote the regeneration of disturbed areas; therefore, effects of RIL on these species is of particular concern. We determined patterns of temporal activity, degree of temporal overlap of activity, and dispersion in peaks of activity for seven abundant species of frugivorous bat in Tapajós National Forest, Pará, Brazil. In addition, we evaluated the effects of RIL at a harvest level of 18.7 m3/ha and habitat physiognomy on temporal patterns of activity for these species. Bats were surveyed for four nights at each of 96 sites for a total sampling effort of 64,512 net-m-h. Sites were distributed among four experimental blocks, two blocks of unlogged forest and two blocks of forest subjected to RIL. Half of the sites in each management type were in forest gaps and half were in closed-canopy forest. In general, species exhibited similar patterns of activity, and greater than expected temporal overlap in activity among species. RIL and forest physiognomy had little effect on activity patterns of species. RIL in Amazonia removes fewer trees than do naturally occurring treefalls and such changes in habitat structure do not alter activity patterns of frugivorous bats. Evidence suggests that RIL does not have an appreciable adverse effect on frugivorous bats in Amazonia. RESUMO A exploração madeireira de impacto reduzido é uma opção viável para o uso sustentável de florestas de planícies tropicais, ao passo em que também minimizam os efeitos sobre a biodiversidade local e processos ecossistêmicos. Avaliações dos efeitos de regimes de derrubada de árvores geralmente se baseiam em respostas em nível populacional ou de comunidades e ignoram respostas comportamentais que podem ter consequências críticas em processos ecossistêmicos locais. Muitos dos morcegos neotropicais filostomídeos proporcionam serviços ecossistêmicos associados à polinização e dispersão de sementes, que promovem regeneração de áreas degradadas. Por esse motivo, os efeitos da exploração madeireira de impacto reduzido, sobre essas espécies, devem ter sua importância considerada. Nós avaliamos padrões temporais de atividade, grau de sobreposição temporal de atividade, e dispersão nos picos de atividade de sete espécies de morcegos frugívoros abundantes na Floresta Nacional de Tapajós, Pará, Brasil. Além disso, avaliamos os efeitos da exploração madeireira de impacto reduzido e da fisionomia de habitat (lacunas florestais e locais de dossel fechado) nos padrões temporais de atividade desses morcegos. Em geral, as espécies exibiram padrões de atividade similares, o que resulta em uma sobreposição temporal maior do que a esperada na atividade das espécies. A exploração madeireira de impacto reduzido e a fisionomia florestal tiveram pouco efeito nos padrões de atividades das espécies observadas. A exploração madeireira ora apresentada (2-4 árvores/ha) se propõe a um impacto menor que o associado às quedas naturais de árvores na Amazônia e aparenta não alterar a estrututra dos habitats de forma significativa à atividade das espécies de morcegos aqui estudadas. Consequentemente, não há evidências para acreditar que a exploração madeireira impacto reduzido possua efeitos adversos em espécies abundantes de morcegos frugívoros na Amazônia ou em suas capacidades de continuar a promover a regeneração de áreas degradadas via polinização ou dispersão de sementes. [source] | ||||||||||