Flora and ecological distribution of macroalgal communities of forest fragments from the northwest region of São Paulo State

Abstract

Thisproject will allow us to test some robust hypotheses: 1) Characteristics of the water bodies, such as substratum availability, shading, length from the source and drainage area, are expected to have more influence on species richness and abundance of macroalgal communities than those related to terrestrial vegetation of each fragment, such as size, contour and preservation stage. 2) the type of surrounding matrix are expected to have a direct influence on macroalgal communities, with the one composed by sugar cane having the higher negative impact than the remaining ones (permanent cultures - rubber plant, orange and coffee - and pasture), due to more soil exposure and the consequent effects on the water bodies (e.g. silting up). 3) the lotic macroalgal flora of the forest fragments as a whole is expected to have a higher similarity to the neighboor biomes/regions of São Paulo State, particularly with the tropical forest and cerrado. In order to test these hypotheses, we propose the following aims: 1)to determine parameters of macroalgal community structure (composition, richness, abundance and diversity) in streams from forest fragments sampled as part of the tematic project; 2) to evaluate the diversity in each forest fragment (alpha diversity) and the difference in species composition among forest fragments (beta diversity); 3) to analyze the influence of the characteristics of the forest fragments (size and shape), as well as of the drainage basin (length and area) on the macroalgal communities; 4) to relate the type of matrix, annual (sugar cane) versus permanent cultures (rubber plant, orange and coffee) and pastures on the macroalgal community structure; 5) to evaluate the influence of abiotic factors (water physical and chemical characteristics, dominant substratum, depth and shading) on the macroalgal community structure. The macroalgal community samplings and the measurements of environmental variables will be made along two years in two sampling periods, both in the dry season (June to August) in 18 forest fragments of the northwest region; nine fragments are considered small (named P1-P9, 50-150 ha) and nine are large (G1-G9, 200 ha). Two fragments (namely P4 and G9) will be sampled twice in consecutive years.