Métodos de amostragem e avaliação utilizados em estudos fenológicos de florestas tropicais
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Data
2004-03-01
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Sociedade Botânica do Brasil
Resumo
Nos últimos 30 anos não foram levadas em consideração questões metodológicas importantes relativas ao estudo da fenologia de plantas. O uso de vários métodos na amostragem e avaliação dos dados fenológicos tem levado a uma grande dificuldade na interpretação e comparação de resultados. Esse estudo tem por objetivos realizar uma revisão da literatura em fenologia de florestas tropicais, compilando informações sobre os métodos de amostragem e avaliação utilizados, e discutir as proporções em que foram utilizados e as aplicações de cada método. Nos 60 estudos avaliados, os métodos de amostragem encontrados distribuem-se da seguinte forma: trilhas (20%), transecções (18%), parcelas (15%), coletores (10%), sendo que 37% dos estudos não definiram o método de amostragem utilizado. Para avaliação fenológica foram levantados dois métodos: qualitativo, presença e ausência das fenofases (20%) e quantitativo com quantificação da intensidade das fenofases (62%), e a combinação entre métodos qualitativos e quantitativos (17%). Ao longo do tempo cresceu a preocupação com a aplicação de métodos de amostragem e de avaliação quantitativa. Entretanto, a falta de padronização no uso desses métodos, mesmo nos dias atuais, ainda se faz presente, resultando na impossibilidade de comparação adequada dos estudos. É imprescindível, portanto, a realização de estudos comparativos de métodos fenológicos com espécies arbóreas em florestas tropicais.
During the last 30 years important methodological questions were not taken into account in the study of plant phenology. The application of different methods for sampling and estimate plant phenology make difficult to interpret and compare phenological studies. We carried out a survey of studies on tropical forest phenology, compiling information about methods applied for sampling individuals and estimate phenology. The methods surveyed were grouped by type and time (decade), and we discuss their proportion of occurrence and applicability. Among the 60 studies analysed, we found the following sampling methods: trails (20%), transects (18%), parcels (15%), and traps (10%). For 37% of the studies the sampling method was not defined. Two methods to estimate plant phenology were surveyed: qualitative or presence/absence of the phenophase (20%), and quantitative, when the intensity of the phenophase is estimated (62%); the combination of both methods occurred on 17% of the studies surveyed. The preoccupation with the application of sampling methods and quantitative estimation of the phenophases has increased over the last 30 years. However, the lack of standardize procedures or the use of some common techniques for sampling and estimate plant phenology persists until today, resulting in the impossibility to perform an adequate comparison among phenological studies. It is necessary and urgent to conduct comparative research of methods to study the phenology of tropical forest trees.
During the last 30 years important methodological questions were not taken into account in the study of plant phenology. The application of different methods for sampling and estimate plant phenology make difficult to interpret and compare phenological studies. We carried out a survey of studies on tropical forest phenology, compiling information about methods applied for sampling individuals and estimate phenology. The methods surveyed were grouped by type and time (decade), and we discuss their proportion of occurrence and applicability. Among the 60 studies analysed, we found the following sampling methods: trails (20%), transects (18%), parcels (15%), and traps (10%). For 37% of the studies the sampling method was not defined. Two methods to estimate plant phenology were surveyed: qualitative or presence/absence of the phenophase (20%), and quantitative, when the intensity of the phenophase is estimated (62%); the combination of both methods occurred on 17% of the studies surveyed. The preoccupation with the application of sampling methods and quantitative estimation of the phenophases has increased over the last 30 years. However, the lack of standardize procedures or the use of some common techniques for sampling and estimate plant phenology persists until today, resulting in the impossibility to perform an adequate comparison among phenological studies. It is necessary and urgent to conduct comparative research of methods to study the phenology of tropical forest trees.
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Palavras-chave
fenologia, métodos em fenologia, avaliação fenológica, floresta tropical, árvores tropicais, phenology, sampling methods, evaluation methods, tropical forest, forest trees
Como citar
Acta Botanica Brasilica. Sociedade Botânica do Brasil, v. 18, n. 1, p. 99-108, 2004.