A diversidade da regeneração natural e fatores que podem influenciar o aumento da riqueza regenerante em áreas em processo de restauração com distintas idades
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Data
2019-02-26
Autores
Aguirre, Andrea Garafulic [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Grandes iniciativas mundiais no esforço de alavancar um aumento na restauração ecológica surgiram recentemente, como a Iniciativa 20 x 20 e a Bonn Challenge, que apresentam como meta conjunta restaurar 500 milhões de hectares até 2030. Assim, uma das metas da ecologia aplicada à restauração é buscar compreender as distintas maneiras pelas quais a vegetação varia durante o processo de restauração e quais fatores influenciam o aumento da riqueza de espécies regenerantes. Este trabalho teve como objetivos: (1) Compreender como variam a abundância relativa e riqueza rarefeita, quando se comparam a regeneração natural total e específica (espécies que ocorreram apenas na área de referência), nas áreas em restauração com diferentes idades. (2) Avaliar como variam a diversidade alfa e beta nas áreas em restauração com idades distintas. (3) Observar a variação na abertura do dossel nas áreas com idades distintas. (4) Analisar se as variáveis da abertura do dossel e a idade são fatores importantes no que tange à influência com o aumento da riqueza de espécies regenerantes. Nove áreas em processo de restauração, localizadas no município de Extrema (Minas Gerais), foram selecionadas com 4, 7 e 10 anos de idade e um fragmento de referência, onde ao todo, 360 parcelas foram instaladas. Em cada parcela foram mensurados todos os regenerantes entre 20 cm e 2 m de altura (ervas, trepadeiras, arbustos, arbóreas e pteridófitas). Resultados: Foram encontrados 6788 regenerantes. As herbáceas e arbóreas tiveram as maiores abundâncias relativas geral e específica. Quando se comparou a riqueza rarefeita total com o fragmento, as áreas com 7 e 10 anos alcançaram o patamar da área de referência. No entanto, quando se comparou a riqueza rarefeita específica, nenhuma área em restauração alcançou a riqueza da área de referência. As áreas com 7 anos foram as que tiveram maior diversidade alfa e as áreas com 10 anos apresentaram os menores índices de maneira geral. Com relação à diversidade beta, observou-se que as áreas apresentaram baixa similaridade. As aberturas do dossel foram significativamente distintas entre as áreas com diferentes idades. As áreas com 10 anos apresentaram um padrão similar (20%) de abertura em suas parcelas ocorrendo o início temporal de homogeneização do dossel. A abertura do dossel e sua variação não apresentaram relação com o aumento da riqueza de espécies regenerantes. Por outro lado, a variável idade mostrou influenciar o aumento da riqueza de espécies. Concluímos que dependo da forma como se avalia a riqueza de espécies, podemos obter resultados distintos quando comparamos a riqueza entre as áreas em restauração e a área de referência. As áreas tiveram uma baixa similaridade, o que demonstra que cada área em restauração tem uma importância única para a preservação das espécies. No caso destas áreas de estudo a idade é uma variável importante e está atrelada a vários fatores, pois com o aumento da idade, há a tendência na formação de um dossel mais estruturado, mais espécies frutificando e maior tempo de chegada de propágulos alóctones.
Major global initiatives in an effort to leverage an increase in the ecological restoration areas have recently emerged, such as the 20 x 20 Initiative and the Bonn Challenge, which aim to restore together 500 million hectares by 2030. Thus, one of the goals of ecology applied to restoration is to look at the different ways in which vegetation varies during the restoration process and what factors influence the increase of regenerating species richness. This work has as objectives: (1) To understand how the relative abundance and rarefied richness vary, when comparing the total and specific natural regeneration (species that occurred only in the reference area) in restoration areas having varying ages. (2) To evaluate how alpha and beta diversity varies in areas of restoration of different ages. (3) To observe the variation in canopy opening in areas of different ages. (4) To analyze whether the variable canopy opening and age are important factors in the influence or relation with the increase of the richness of regenerating species. Nine areas aged 4,7 and 10 under restoration process were selected and a reference fragment, in which a total of 360 parcels were installed. All the areas are located in the Municipality of Extrema, Minas Gerais. In each plot was measured all regenerants between 20 cm and 2 m in height (herbs, climbers, shrubs, trees and pteridophytes). Results: 6788 regenerants were found. Herbs and trees had the highest relative abundances, general and specific. When comparing the total rarefied richness with the fragment, the areas aged 7 and 10 years reached the level of the reference area. However, when the rarefied specific richness was compared, no area in restoration reached the wealth of the reference area. The areas aged 7 years were those, which had greater diversity alpha, and the areas aged 10 years presented the lowest indices. Regarding the beta diversity, it was observed that the areas presented low similarity. Canopy openings were significantly different between areas of different ages. The areas aged 10 years were presented a similar pattern (20%) of opening in their plots, causing the temporal onset of canopy homogenization. The canopy opening, and its variation was not related to the increase of the richness of regenerating species. On the other hand, the variable age showed to influence the increase of species richness. Thus, we can get to the conclusion that depending on the way we evaluate species richness, we may obtain a large range of different results when comparing the richness between the areas under restoration and the reference area. The areas had a low similarity, which shows that each area under restoration has a unique importance for the preservation of the species. In relation to this study age is an important variable is linked to several factors, because of the increase of age, there is a trend in the formation of a more structured canopy, more fruiting species and longer arrival time of alien propagules.
Major global initiatives in an effort to leverage an increase in the ecological restoration areas have recently emerged, such as the 20 x 20 Initiative and the Bonn Challenge, which aim to restore together 500 million hectares by 2030. Thus, one of the goals of ecology applied to restoration is to look at the different ways in which vegetation varies during the restoration process and what factors influence the increase of regenerating species richness. This work has as objectives: (1) To understand how the relative abundance and rarefied richness vary, when comparing the total and specific natural regeneration (species that occurred only in the reference area) in restoration areas having varying ages. (2) To evaluate how alpha and beta diversity varies in areas of restoration of different ages. (3) To observe the variation in canopy opening in areas of different ages. (4) To analyze whether the variable canopy opening and age are important factors in the influence or relation with the increase of the richness of regenerating species. Nine areas aged 4,7 and 10 under restoration process were selected and a reference fragment, in which a total of 360 parcels were installed. All the areas are located in the Municipality of Extrema, Minas Gerais. In each plot was measured all regenerants between 20 cm and 2 m in height (herbs, climbers, shrubs, trees and pteridophytes). Results: 6788 regenerants were found. Herbs and trees had the highest relative abundances, general and specific. When comparing the total rarefied richness with the fragment, the areas aged 7 and 10 years reached the level of the reference area. However, when the rarefied specific richness was compared, no area in restoration reached the wealth of the reference area. The areas aged 7 years were those, which had greater diversity alpha, and the areas aged 10 years presented the lowest indices. Regarding the beta diversity, it was observed that the areas presented low similarity. Canopy openings were significantly different between areas of different ages. The areas aged 10 years were presented a similar pattern (20%) of opening in their plots, causing the temporal onset of canopy homogenization. The canopy opening, and its variation was not related to the increase of the richness of regenerating species. On the other hand, the variable age showed to influence the increase of species richness. Thus, we can get to the conclusion that depending on the way we evaluate species richness, we may obtain a large range of different results when comparing the richness between the areas under restoration and the reference area. The areas had a low similarity, which shows that each area under restoration has a unique importance for the preservation of the species. In relation to this study age is an important variable is linked to several factors, because of the increase of age, there is a trend in the formation of a more structured canopy, more fruiting species and longer arrival time of alien propagules.
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Palavras-chave
Idade, Abertura de dossel, Regeneração natural, Diversidade alfa, Diversidade beta, Age, Canopy opening, Natural regeneration, Alpha diversity, Beta diversity