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Zooplankton species richness–productivity relationship: Confronting monotonic positive and hump‐shaped models from a local perspective
Author(s) -
Simões Nadson R.,
Colares Maria Alice Mendes,
LansacTôha Fábio A.,
Bonecker Claudia C.
Publication year - 2013
Publication title -
austral ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.688
H-Index - 87
eISSN - 1442-9993
pISSN - 1442-9985
DOI - 10.1111/aec.12038
Subject(s) - species richness , productivity , ecology , zooplankton , dominance (genetics) , abundance (ecology) , species evenness , biology , economics , biochemistry , macroeconomics , gene
This study examined two models that are most frequently used to describe the relationship between species richness and productivity ( SPR ): monotonic positive and hump‐shaped models. We assessed zooplankton community diversity in response to algal productivity. The relationship between net primary productivity ( NPP ) and rarefied species richness was examined by fitting the data to two models and comparing them using the A kaike information criterion ( AICc ). Macrophyte banks with the highest net primary productivity had the highest zooplankton abundance. Our results pointed to a hump‐shaped model as the best fit to describe the relationship between zooplankton species richness and primary productivity (Δ AICc > 4). Thus, the diversity was lower at the extremes of productivity and higher at intermediate levels of productivity. We suggest that this relationship might occur because when the resource supply rates are low, environmental conditions are stressful, whereas a high availability of resources enhances competitive exclusion. Two observations supported this statement: (i) the total abundance of the community positively correlated with NPP ( P < 0.05), indicating that less productive sites had few consumers and the raised productivity tended to favour the total abundance; (ii) NPP was negatively correlated with evenness ( P < 0.05), indicating that productivity increased the dominance of certain species in the communities. Therefore, we challenged two of the models most frequently used to explain SPR , and discuss some mechanisms underlying a hump‐shaped SPR .