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| Registros recuperados: 414 | |
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| Barthel, Stephan; Stockholm Resilience Centre, Stockholm University, Sweden; Department of History, Stockholm University, Stockholm, Sweden; stephan.barthel@historia.su.se; Crumley, Carole L.; Stockholm Resilience Centre, Stockholm University, Sweden; Department of Archaeology and Ancient History, Uppsala University, Uppsala, Sweden; Swedish Biodiversity Centre, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden; crumley@live.unc.edu; Svedin, Uno; Stockholm Resilience Centre, Stockholm University, Sweden ; uno.svedin@gmail.com. |
| Tipo: Peer-Reviewed article |
Palavras-chave: Agriculture; Biocultural refugia; Diversity; Ecosystem restoration; Resilience; Small holders; Stewardship. |
| Ano: 2013 |
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| Cilliers, Paul; University of Stellenbosch; fpc@sun.ac.za; Biggs, Harry C.; South African National Parks; biggs@sanparks.org; Blignaut, Sonja; The Narrative Lab; sonja@narrativelab.co.za; Choles, Aiden G.; The Narrative Lab; aiden@narrativelab.co.za; Hofmeyr, Jan-Hendrik S.; University of Stellenbosch; jhsh@sun.ac.za; Jewitt, Graham P. W.; University of Kwazulu Natal; jewittg@ukzn.ac.za; Roux, Dirk J.; South African National Parks; Nelson Mandela Metropolitan University; Monash South Africa; dirkr@sanparks.org. |
| This paper contends that natural resource management (NRM) issues are, by their very nature, complex and that both scientists and managers in this broad field will benefit from a theoretical understanding of complex systems. It starts off by presenting the core features of a view of complexity that not only deals with the limits to our understanding, but also points toward a responsible and motivating position. Everything we do involves explicit or implicit modeling, and as we can never have comprehensive access to any complex system, we need to be aware both of what we leave out as we model and of the implications of the choice of our modeling framework. One vantage point is never sufficient, as complexity necessarily implies that multiple (independent)... |
| Tipo: Peer-Reviewed Synthesis |
Palavras-chave: Complex systems; Diversity; Management; Mental models; Resilience; Social complexity; Social– Ecological systems. |
| Ano: 2013 |
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| The diversity, expressed as species richness in equal-sized samples, of wood-living beetles in successional stages of deciduous forest after forest fires approximately 100 years ago did not differ between patch sizes in this study. Thus, the crucial question for conservation is whether the lack of reduction in diversity in small patches means that a number of small patches can elevate the regional diversity as efficiently as can one larger area. In the present study, the smaller patches did not differ from larger patches in substrate availability, quality, or heterogeneity. The frequency of a group of species was measured as the number of occurrences, viz. the number of trees on which a species was found, summed over all species in the group. The number of... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Alpha (local) diversity; Beta (between-habitats) diversity; Deciduous forest; Disturbance; Diversity; Fire; Gamma (regional) diversity; Invasion; Matrix habitat; Patch size; Species-richness.. |
| Ano: 1999 |
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| Nielsen, Scott; University of Alberta; scottn@ualberta.ca; Kirschbaum, Chad; University of Michigan; ckirschb@umich.edu; Haney, Alan; University of Wisconsin-Stevens Point; ahaney@uwsp.edu. |
| We investigated vegetation responses in terms of canopy, ground-layer diversity, and ecological species groups using two restoration treatments at two degraded oak barren and savanna sites in central Wisconsin, USA. The two restoration models tested were (1) process-only, which reintroduced fire in the form of prescribed burning, and (2) structural manipulation, which used prescribed burning following selective timber removal. Both methods have been widely promoted, debated, and investigated in the fire-prone ecosystems of western North America, but they have not been studied in midwestern ecosystems. Vegetation was monitored in permanent quadrats prior to and following treatment applications. All treatment responses were compared against trends at control... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Carex pensylvanica; Diversity; Wisconsin; Holdover species; Modal species; Oak barrens; Process-only; Restoration; Savannas; Structural manipulation. |
| Ano: 2003 |
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| Cane, James H; USDA-ARS; jcane@biology.usu.edu. |
| Few studies directly address the consequences of habitat fragmentation for communities of pollinating insects, particularly for the key pollinator group, bees (Hymenoptera: Apiformes). Bees typically live in habitats where nesting substrates and bloom are patchily distributed and spatially dissociated. Bee studies have all defined habitat fragments as remnant patches of floral hosts or forests, overlooking the nesting needs of bees. Several authors conclude that habitat fragmentation is broadly deleterious, but their own data show that some native species proliferate in sampled fragments. Other studies report greater densities and comparable diversities of native bees at flowers in some fragment size classes relative to undisrupted habitats, but find... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: Apoidea; Bees; Conservation; Diversity; Habitat fragmentation; Land-use change; Pollination; Pollinator; Statistics; Taxonomy. |
| Ano: 2001 |
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| Roubik, David Ward; Smithsonian Tropical Research Institute; roubikd@tivoli.si.edu. |
| Plant-pollinator systems inherently possess wide variation that limits the applicability of surveys on population dynamics or diversity. Stable habitats are scarcely studied, whereas dynamics in unprotected habitats are less predictable or more compromised by exotic organisms (Apis, in the case of bee surveys). An extensively replicated, long-term study of orchid-bees (Euglossini) was made in protected tropical moist forest in Panama. Over 47,000 bees were recorded in 124 monthly censuses employing 1952 counts. No aggregate trend in abundance occurred (from 1979 to 2000), although four individual species declined, nine increased, 23 showed no change, and species richness was stable. No rare or parasitic species showed decreasing trends, while the most... |
| Tipo: Peer-Reviewed Reports |
Palavras-chave: ENSO; Euglossini; Abundance variability; Bees; Census techniques; Diversity; Pollinators; Trends; Tropical- temperate comparisons. |
| Ano: 2001 |
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| Lutinski,Junir Antonio; Lutinski,Cladis Juliana; Iop,Samanta; Mello Garcia,Flávio Roberto. |
| This study evaluated the efficiency as a tool for ant survey of a sampling protocol composed of six methods, and examined the role of environmental features on the efficiency of methods complementarity . We applied them in three environments (pine, eucalyptus and native forest) in the National Forest of Chapecó and the effect of the characteristics of these environments on methods complementarity. The sampling methods were pitfall traps, two types of bait (sardines and glucose), sweep net, entomological umbrella and Malaise trap. The protocol efficiency of the protocol in the ant inventory was evaluated based on rarefaction curves, richness estimators and records of occurrence of ants. The protocol captured the greatest richness on native forest... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bait; Composition; Conservation planning; Diversity; Richness. |
| Ano: 2013 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S1667-782X2013000100005 |
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| Letelier,Luis; Valderrama,Aly; Stoll,Alexandra; García-Gonzáles,Rolando; González-Rodríguez,Antonio. |
| ABSTRACT Sclerophyllous forest is among the most representative types of woody plant communities in central Chile where Quillaja saponaria is considered to be one of the most important species. In this study, we analysed the main factors that explain the geographical patterns of variation in composition, richness and phylogenetic diversity of woody plant communities in the Chilean sclerophyllous forest where Quillaja saponaria is present. Vegetation surveys were performed for trees and shrubs in thirty-nine sites from 30° to 38° of latitude South in the Mediterranean biome of Chile. Composition, richness, alfa diversity and phylogenetic diversity metrics of the communities were calculated and associated with spatial (latitude, longitude and altitude),... |
| Tipo: Journal article |
Palavras-chave: Diversity; Forest fragmentation; Mediterranean flora; Phylogenetic diversity; Vegetation matrix. |
| Ano: 2017 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432017000100057 |
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| Vargas,Rafael S.; Bataiolli,Renata; da Costa,Pedro B.; Lisboa,Bruno; Passaglia,Luciane Maria P.; Beneduzi,Anelise; Vargas,Luciano K.. |
| The aim of this study was to evaluate the impact of different grazing pressures on the activity and diversity of soil bacteria. We performed a long-term experiment in Eldorado do Sul, southern Brazil, that assessed three levels of grazing pressure: high pressure (HP), with 4% herbage allowance (HA), moderate pressure (MP), with 12% HA, and low pressure (LP), with 16% HA. Two reference areas were also assessed, one of never-grazed native vegetation (NG) and another of regenerated vegetation after two years of grazing (RG). Soil samples were evaluated for microbial biomass and enzymatic (β-glucosidase, arylsulfatase and urease) activities. The structure of the bacterial community and the population of diazotrophic bacteria were evaluated by RFLP of the 16S... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bacterial diversity; Diazotrophic bacteria; Diversity; Grasslands; Soil microbial communities. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572015000200205 |
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| Aggarwal,Rashmi; Kulshreshtha,Deepika; Sharma,Sapna; Singh,Vaibhav K.; Manjunatha,Channappa; Bhardwaj,Subhash C.; Saharan,Mahender S.. |
| Abstract Stripe rust caused by Puccinia striiformis f. sp. tritici (Pst) is one of the most devastating diseases of wheat (Triticum spp.) worldwide. Indian isolates were characterised based on their phenotypic reaction on differential hosts carrying different Yr genes. Based on virulence/avirulence structure, isolates were characterised into ten different pathotypes viz. 70S0-2, 67S64, 70S4, 66S0, 70S64, 66S64-1, 38S102, 47S102, 46S119, and 78S84. These Indian pathotypes of P. striiformis f. sp. tritici and 38 pathotypes of other rust species (P. graminis tritici and P. triticina) were used in this study to analyze their molecular phylogenetic relationship. The nucleotides of rDNA-ITS, partial β-tubulin and ketopantoate reductase genes of all the... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wheat; Stripe rust; Virulence; Diversity; Phylogeny. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572018000500834 |
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| Almerão,Mauricio Pereira; Fagundes,Nelson Jurandi Rosa; Araújo,Paula Beatriz de; Verne,Sébastien; Grandjean,Frédéric; Bouchon,Didier; Araújo,Aldo Mellender. |
| Wolbachia are endosymbiotic bacteria that commonly infect arthropods, inducing certain phenotypes in their hosts. So far, no endemic South American species of terrestrial isopods have been investigated for Wolbachia infection. In this work, populations from two species of Balloniscus (B. sellowii and B. glaber) were studied through a diagnostic PCR assay. Fifteen new Wolbachia 16S rDNA sequences were detected. Wolbachia found in both species were generally specific to one population, and five populations hosted two different Wolbachia 16S rDNA sequences. Prevalence was higher in B. glaber than in B. sellowii, but uninfected populations could be found in both species. Wolbachia strains from B. sellowii had a higher genetic variation than those isolated from... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Wolbachia; Prevalence; Diversity; South America; Oniscidea. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572012000600013 |
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| Santana,Priscila Bessa; Ghilardi Junior,Rubens; Alves,Claudio Nahum; Silva,Jeronimo Lameira; McCulloch,John Anthony; Schneider,Maria Paula Cruz; Silva,Artur da Costa da. |
| Methanogenic archaeans are organisms of considerable ecological and biotechnological interest that produce methane through a restricted metabolic pathway, which culminates in the reaction catalyzed by the Methyl-coenzyme M reductase (Mcr) enzyme, and results in the release of methane. Using a metagenomic approach, the gene of the a subunit of mcr (mcrα) was isolated from sediment sample from an anoxic zone, rich in decomposing organic material, obtained from the Tucuruí hydroelectric dam reservoir in eastern Brazilian Amazonia. The partial nucleotide sequences obtained were 83 to 95% similar to those available in databases, indicating a low diversity of archaeans in the reservoir. Two orders were identified -the Methanomicrobiales, and a unique Operational... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Amazonian; Archaea; Diversity; Methyl-coenzyme M reductase; Mcrα; Homology modeling. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572012000100018 |
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| Souza-Chies,Tatiana T.; Santos,Eliane Kaltchuk dos; Eggers,Lilian; Flores,Alice Mainieri; Alves,Eudes M. Stiehl; Fachinetto,Juliana; Lustosa,Juliana; Corrêa,Lauís Brisolara; Tacuatiá,Luana Olinda; Piccoli,Paula; Miz,Rogéria Beatriz. |
| Plants of the family Iridaceae are well represented in the grassland vegetation of southern Brazil, occurring in the Pampa and Atlantic Forest biomes. Nevertheless, little is known about the taxonomy and evolution of Iridaceae species in southern Brazil. The main goal of this review is to compile published information about South American Iridaceae, and to discuss the evolution and genetic diversity of the family presenting our own research data in the light of the published literature. The main focus is on the genera Calydorea, Cypella, Herbertia, and Sisyrinchium. Aspects of reproductive system and of pollinator attraction are also discussed. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cytotaxonomy; Molecular phylogenetics; Iridoideae; Population genetics; Diversity. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572012000600018 |
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| Registros recuperados: 414 | |
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