Relationship between zooplankton richness and area in Brazilian lakes: comparing natural and artificial lakes and trends

Relações entre a riqueza do zooplâncton e a área em lagos brasileiros: comparando lagos naturais e artificiais e tendências

Abstract

Aim

We analyzed the relationship between zooplankton species richness and the area of ​​34 natural and 55 artificial lakes in Brazil (total of 89), with area varying between 0.01 to 2,430 km².

Methods

A total of 33 studies were found in the specialized bibliography, containing data from zooplankton sampled in the limnetic areas, here analyzed through descriptive statistics, nonparametric group comparisons, Spearman correlation, and non-linear regression.

Results

The relationship between zooplankton richness and area in Brazilian lakes depend both on the size and type of the environments. Contradicting aspects of the biogeographic theory, in small environments (up to 6 km²) there is no significant influence of the area on the richness, whether it is natural (ponds) or artificial (dams, reservoirs). The natural lakes present greater richness and habitat variation independent of the size, possibly due to a more diverse composition of niches. Large natural lakes are scarce in Brazil but, with dams, area and zooplankton richness are positively correlated on an intermediate scale, up to 39 km², critical point of size from which species’ richness stabilizes.

Conclusions

For the artificial lakes of large or intermediate size in Brazil, area and richness of microcrustaceans have a point from which richness starts to stabilize, as would be expected by the biogeographic theory. But in small size environments there is no evidence confirming this association. Also, it is observed that the natural lakes present higher and more variable values for richness than the artificial ones.

Keywords:
Cladocera; Copepoda; ecology; diversity