ABSTRACT
Fractals seemed to have permeated most of scientific fields, including ecology. In fact, biodiversity and ecological processes are affected by spatial complexity, and fractals can help understand patterns at multiple scales. In this paper we evaluated the main quantitative trends and the profile of ecological publications using fractals. Publication about fractals in Ecology experienced a high increase in the last two decades and most articles were published in high visible ecological journals. However, studies were authored mainly by Americans, and researchers from developing countries had a minor contribution. In addition, studies were highly biased towards terrestrial environments, and empirical approaches were preferred.
Fractals seemed to have permeated most scientific fields, including ecology. In fact, biodiversity and ecological processes are affected by spatial complexity, and fractals can help understand patterns at multiple scales. In this paper we evaluated the main quantitative trends and the profile of ecology publications using fractals. Publications about fractals in Ecology experienced a high increase in the last two decades, and most articles were published in highly visible ecology journals. However, studies were authored mainly by US scientists, and researchers from developing countries had a minor contribution. In addition, studies were highly biased towards terrestrial environments, and empirical approaches were preferred.
ABSTRACT
Anthropic activities cause changes in physical and chemical characteristics in aquatic environments, as well as in the biotic component, and several benthic invertebrates species may indicate these changes. In this paper, we characterized the environmental conditions of different sample points in the 119 River, Campo Mourão, State of Paraná, Brazil. Physical and chemical conditions were analyzed in water, and samples of the river substrate were collected for physical and biological analysis. Density, composition and taxa richness of benthic invertebrates were used to distinguish the sampling points according to environmental changes. Alterations in density, composition and richness were reported at all sampling points and samplings, mainly in sites downstream from areas with anthropic changes. Some characteristic taxa of locals with good water quality were recorded, but in smaller numbers compared with taxa that indicate environmental changes. Because the river crosses the urban area, it suffers continuous anthropic pressure and organism distribution throughout this gradient responds to the changes that occur in each sampling point. Thus, our results suggest that an immediate management plan is necessary to recover the whole river along the urban area
As atividades antrópicas podem causar profundas alterações nas características físicas e químicas dos ambientes aquáticos, assim como na biota. Muitas espécies de invertebrados bentônicos podem auxiliar a indicação dessas alterações. No presente estudo, foi realizada a caracterização das condições ambientais de diferentes pontos do rio 119, Campo Mourão, Paraná, Brasil. Para tanto, foram analisadas condições físico-químicas da água e coletadas amostras do substrato do rio para análises físicas e biológicas. A densidade, a composição e a riqueza dos táxons de invertebrados bênticos encontrados foram utilizadas para diferenciar os pontos quanto às condições de alteração ambiental. Mudanças na densidade, na composição e na riqueza foram relatadas em todos os pontos de coleta, principalmente em locais a jusante de áreas alteradas antropicamente. Alguns táxons característicos de locais com boa qualidade de água foram registrados, mas em número inferior ao de táxons que indicam alterações ambientais. Por ser um rio que corta longitudinalmente o perímetro urbano, ele sofre pressão antrópica contínua, e a distribuição dos organismos ao longo desse gradiente provavelmente está respondendo às alterações ocorridas em cada local de coleta. Dessa forma, sugere-se a implementação imediata de um plano de manejo e recuperação para todo o rio ao longo do perímetro urbano
ABSTRACT
The invertebrate colonization was investigated during 56-day decomposition of two macrophytes species (Eichhornia azurea and Polygonum ferrugineum). The aim was to determine the role of macroinvertebrates in the process of leaf fragmentation. During material analysis, 2096 invertebrates were associated with E.azurea and 6154 were associated with P. ferrugineum, identified in 18 taxons, with predominance of Diptera larvae (Chironomidae family specially), followed by Oligochaeta species and microcrustaceans such as Cladocera and Copepoda. In both macrophytes the macroinvertebrates showed a significant increase of density through the process of decomposition, which is probably associated with the loss of phenolic compounds. Results suggest that macrophytes specimens show specific associations with their consumers, i.e., the succession process of colonization becomes singular according to the phenolic characteristics of the plant.
A colonização de invertebrados durante o período de 56 dias de decomposição de duas espécies de plantas aquáticas (Eichhornia azurea e Polygonum ferrugineum) foi investigada para determinar o papel de macroinvertebrados no processo de fragmentação da folha. Durante a análise do material, foi constatado um total de 2096 invertebrados, associados a E.azurea e 6154 invertebrados associados a P. ferrugineum, identificados dentro de 18 táxons, com predominância de larvas de Diptera da família Chironomidae, seguido por espécimes de Oligochaeta, microcrustáceos como Cladocera e Copepoda. Em ambas as plantas, os macroinvertebrados mostraram um aumento significativo de densidade ao longo do processo de decomposição, o que provavelmente está associado à perda de compostos fenólicos. Os resultados sugerem que as espécies de macrófitas apresentam associações específicas com seus consumidores, ou seja, o processo de sucessão da colonização torna-se diferenciado de acordo com as características fenológicas da planta.