TY  - JOUR
A1  - Quintana, Xavier D.
A1  - Arim, Matias
A1  - Badosa, Anna
A1  - Maria Blanco, Jose
A1  - Boix, Dani
A1  - Brucet, Sandra
A1  - Compte, Jordi
A1  - Egozcue, Juan J.
A1  - de Eyto, Elvira
A1  - Gaedke, Ursula
A1  - Gascon, Stephanie
A1  - Gil de Sola, Luis
A1  - Irvine, Kenneth
A1  - Jeppesen, Erik
A1  - Lauridsen, Torben L.
A1  - Lopez-Flores, Rocio
A1  - Mehner, Thomas
A1  - Romo, Susana
A1  - Sondergaard, Martin
T1  - Predation and competition effects on the size diversity of aquatic communities
JF  - Aquatic sciences : research across boundaries
N2  - Body size has been widely recognised as a key factor determining community structure in ecosystems. We analysed size diversity patterns of phytoplankton, zooplankton and fish assemblages in 13 data sets from freshwater and marine sites with the aim to assess whether there is a general trend in the effect of predation and resource competition on body size distribution across a wide range of aquatic ecosystems. We used size diversity as a measure of the shape of size distribution. Size diversity was computed based on the Shannon-Wiener diversity expression, adapted to a continuous variable, i.e. as body size. Our results show that greater predation pressure was associated with reduced size diversity of prey at all trophic levels. In contrast, competition effects depended on the trophic level considered. At upper trophic levels (zooplankton and fish), size distributions were more diverse when potential resource availability was low, suggesting that competitive interactions for resources promote diversification of aquatic communities by size. This pattern was not found for phytoplankton size distributions where size diversity mostly increased with low zooplankton grazing and increasing nutrient availability. Relationships we found were weak, indicating that predation and competition are not the only determinants of size distribution. Our results suggest that predation pressure leads to accumulation of organisms in the less predated sizes, while resource competition tends to favour a wider size distribution.
KW  - Phytoplankton
KW  - Zooplankton
KW  - Fish
KW  - Size distribution
KW  - Predation
KW  - Competition
KW  - Compositional data analysis
Y1  - 2015
U6  - https://doi.org/10.1007/s00027-014-0368-1
SN  - 1015-1621
SN  - 1420-9055
VL  - 77
IS  - 1
SP  - 45
EP  - 57
PB  - Springer
CY  - Basel
ER  - 
TY  - JOUR
A1  - Hilt, Sabine
A1  - Wanke, Thomas
A1  - Scharnweber, Inga Kristin
A1  - Brauns, Mario
A1  - Syvaranta, Jari
A1  - Brothers, Soren M.
A1  - Gaedke, Ursula
A1  - Köhler, Jan
A1  - Lischke, Betty
A1  - Mehner, Thomas
T1  - Contrasting response of two shallow eutrophic cold temperate lakes to a partial winterkill of fish
JF  - Hydrobiologia : acta hydrobiologica, hydrographica, limnologica et protistologica
N2  - Food-web effects of winterkill are difficult to predict as the enhanced mortality of planktivorous fish may be counterbalanced by an even higher mortality of piscivores. We hypothesised that a winterkill in a clear and a turbid shallow lake would equalise their fish community composition, but seasonal plankton successions would differ between lakes. After a partial winterkill, we observed a reduction of fish biomass by 16 and 43% in a clear-water and a turbid small temperate lake, respectively. Fish biomass and piscivore shares (5% of fish biomass) were similar in both lakes after this winterkill, but young-of-the-year (YOY) abundances were higher in the turbid lake. Top-down control by crustaceans was only partly responsible for low phytoplankton biomass at the end of May following the winterkill in both lakes. Summer phytoplankton biomass remained low in the clear-water lake despite high abundances of YOY fish (mainly roach). In contrast, the crustacean biomass of the turbid lake was reduced in summer by a high YOY abundance (sunbleak and roach), leading to a strong increase in phytoplankton biomass. The YOY abundance of fish in shallow eutrophic lakes may thus be more important for their summer phytoplankton development after winterkill than the relative abundance of piscivores.
KW  - Anoxia
KW  - Fish
KW  - Regime shifts
KW  - Roach
KW  - Shallow lakes
KW  - Submerged macrophytes
Y1  - 2015
U6  - https://doi.org/10.1007/s10750-014-2143-7
SN  - 0018-8158
SN  - 1573-5117
VL  - 749
IS  - 1
SP  - 31
EP  - 42
PB  - Springer
CY  - Dordrecht
ER  -