Two species of swimming crabs of the genus Achelous (Crustacea, Brachyura): environmental requirements determining the niche

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Variance partitioning of deconstructed periphyton communities: does the use of biological traits matter?

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Broad-scale spatial patterns of canopy cover and pond morphology affect the structure of a Neotropical amphibian metacommunity

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of habitat homogenization on the trophic structure of fish fauna in tropical streams

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The roles of environmental conditions and spatial factors in controlling stream macroalgal communities

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spatial heterogeneity affecting fish fauna in cascade reservoirs of the Upper Parana Basin, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Should phylogenetic and functional diversity metrics compose macroinvertebrate multimetric indices for stream biomonitoring?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biodiversity analyses: are aquatic ecologists doing any better and differently than terrestrial ecologists?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The relationship between macroalgal morphological complexity and hydraulic conditions in stream habitats

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Macroalgae of a stream in southeastern Brazil: composition, seasonal variation and relation to physical and chemical variables

Macroalgal seasonality was studied monthly in a second-order stream in the north-west of São Paulo State, S.E. Brazil. Seasonal variation was based on frequency and percentage cover. Seven species were found during the study period, three of which ('Chantransia' stage of Sirodotia delicatula, Homoeothrix juliana and Klebsormidium subtile) were encountered throughout the year and showed well-defined seasonal patterns as well as the highest value of frequency and percentage cover. 'Chantransia' and H. juliana dominated in summer and fall, while for K. subtile winter was the most favourable period. The remaining species (Oscillatoria agardhii, Microcoleus subtorulosus, Oedogonium sp. and Chaetophora elegans) had no clear seasonal pattern, in addition to their low values of frequency and percentage cover. Individually, K. subtile correlated with higher number of physical and chemical variables (oxygen, pH, precipitation, temperature, daylength, conductance and turbidity) than 'Chantransia' and H. juliana (discharge and depth). Principal component analyses revealed that no single variable was responsible for the macroalgal seasonal dynamics. The variables most closely related to seasonal variation of the macroalgal community were daylength, precipitation, discharge, turbidity and dissolved oxygen. Precipitation and flow were suggested as key factors in determining seasonality of the macroalgae. © 1991 Kluwer Academic Publishers.

Distribution of stream macroalgae in the northwest region of Sao Paulo State, southeastern Brazil

Forty-four stream segments were sampled from May to October in 1992 and 1993 in the northwest region of São Paulo State, southeastern Brazil (19 degrees 45'-21 degrees 25'S, 49 degrees 05'-51 degrees 30'S). Thirty-six macroalgal subgeneric taxa were found and Chlorophyta was the dominant algal group (47% species), followed by Cyanophyta (33.5%), Rhodophyta (14%) and Chrysophyta (5.5%). The most widespread species were Stigeoclonium helveticum (25% sites), Batrachospermum delicatulum and Compsopogon coeruleus (20.5%). Distribution was patchy, with species number per sampling site ranging from 0 to six (3.1 +/- 1.7) and correlated positively with species abundance. Species cover ranged from 0 to 61% of the stream bottom (19.1 +/- 19.7%). Most sites (57%) were dominated by one or two macroalgae species. No significant difference was found between the frequency distribution of variables measured for streams and for total macroalgae, but the most widespread species differed for most parameters and occurred over wider ranges of environmental conditions. Mean species number and abundance were close to values found in distinct regions or biomes of North America. Higher conductance and lower oxygen values, as well as rocky substrata, generally constituted the most favourable combination of conditions for the development of macroalgae in the region. The pattern of strong dominance of few species was considered to be typical for stream macroalgal communities in general.