Soraia Diniz

Diversidade e ocorrência de Asteraceae em cerrados de São Paulo

De abril a maio de 2000 a 2002 oito localidades com remanescentes de cerrados sensu stricto no estado de Sao Paulo foram amostradas para o levantamento das especies de asteraceas, uma das familias mais representativas da flora herbaceo-arbustiva nestas formacoes. Foram feitas 23 amostragens e cada area de estudo foi amostrada em media uma vez por ano durante o pico de floracao das plantas. Ao todo foram obtidas 399 amostras, nas quais foram reconhecidas 89 morfoespecies (74 foram identificadas como especies conhecidas). Quarenta por cento das especies foram registradas uma unica vez (unicatas), indicando um grande numero de especies raras. Apenas 10% das especies que ocorreram em mais de uma amostra foram obtidas de uma mesma area (sobreposicao espacial) ou de um mesmo ano de estudo (sobreposicao temporal). A riqueza de especies em cada area foi estimada por meio de transecoes e depois comparada a riqueza total observada em cada area de estudo, sendo esta na maioria das vezes mais alta que a estimada com base nas transecoes. A lista de especies obtida para os cerrados amostrados foi comparada a outras 24 listas publicadas para cerrados no Brasil. Embora a maioria das especies mais comuns tenha coincidido, oito especies (11% das especies identificadas) nao constam das listas publicadas. Concluimos que as areas de cerrado sensu stricto estudadas no estado de Sao Paulo encontram-se isoladas, com uma grande parte da flora herbaceo-arbustiva composta por varias especies raras e exclusivas. Diante deste quadro, sugerimos que a manutencao da biodiversidade de Asteraceae depende da conservacao de todo o conjunto de remanescentes de cerrado do estado de Sao Paulo.

Assemblages of endophagous insects on Asteraceae in São Paulo Cerrados

A survey of the endophagous insects fauna associated to Asteraceae capitula was carried out from 2000 to 2002 in eight cerrado sensu stricto sites located in the Brazilian state of Sdo Paulo. Sixty-four endophagous species of Diptera and Lepidoptera were recorded from 49 asteracean host plants. Approximately half of the species were obtained from a single locality, with a large proportion emerging from a single sample (unicates). Thirty percent of the species were singletons (i.e. only one individual was recorded). The large proportion of rare species suggests a high species turnover among localities. Lepidopteran species were recorded on more host species than dipterans, confirming their more polyphagous food habit, also observed in other Brazilian biomes and in Europe. We conclude that the studied cerrado localities, all within São Paulo State, are isolated with its invertebrate fauna composed of many rare and exclusive species. We suggest that the maintenance of Asteraceae biodiversity and their endophagous insects depend on the conservation of all cerrado remnants in the state.

Habitat heterogeneity, richness and structure of assemblages of dung beetles (Scarabaeidae: Scarabaeinae) in areas of cerrado in the Chapada dos Parecis, Mato Grosso state, Brazil.

Ecological theory of habitat heterogeneity and limited niche-similarity assumes that more heterogeneous environments provide a greater amount and diversity of resources than simple environments, resulting in a greater diversity of species. This study aimed to evaluate the effect of the habitat heterogeneity on the richness of dung beetles and to examine the spatial patterns of assemblage structure in relation to patterns of habitat heterogeneity. Dung beetles were collected using pitfall traps without bait in 30 points distributed in an area of cerrado sensu lato, in the region of Tangará da Serra, MT, Brazil, including areas of cerrado sensu stricto, campo sujo, cerradão and gallery forest. A total of 1,291 dung beetles were collected, distributed in 16 genera and 29 species. Overall habitat heterogeneity exerted a negative effect on patterns of dung beetles richness. Higher levels of species richness were observed in areas of cerrado campo sujo, while the areas of gallery forest were the most species poor. Regarding assembly structure, it was found that the dung beetles were separated into two major groups, one formed by the presence of specialized species in forest areas and other composed of species that occurred predominantly in cerrado. In conclusion, it was found that habitat complexity influenced the distribution of dung beetles, but the level of turnover in species composition along the heterogeneity gradient was relatively weak.