TY - JOUR
T1 - Impact of fish predation on coexisting Daphnia taxa: a partial test of the temporal hybrid superiority hypothesis
AU - Declerck, S.
AU - De Meester, Luc
N1 - WOS:000184071400005
ISI Document Delivery No.: 699TE Times Cited: 15 Cited Reference Count: 29 Declerck, S De Meester, L Declerck, Steven/E-4338-2010; De Meester, Luc/F-3832-2015 Declerck, Steven/0000-0001-6179-667X; De Meester, Luc/0000-0001-5433-6843 18 0 8 Kluwer academic publ Dordrecht
21
PY - 2003
Y1 - 2003
N2 - Fish predation was tested as a factor mediating the coexistence of Daphnia taxa in the shallow, hypertrophic Lake Blankaart. Naturally co-occurring populations of D. galeata and the hybrid D. galeata x cucullata were subjected to different levels of fish predation in in situ enclosures. In control enclosures without fish, the largest taxon D. galeata rapidly became dominant over the intermediate sized D. galeata x cucullata, mainly as a result of higher birth rates. In enclosures with fish, population densities of D. galeata dropped relative to D. galeata x cucullata, due to higher mortality rates. These results are in concordance with the 'temporal hybrid superiority hypothesis', and can be explained by a higher vulnerability of the large and more conspicuous D. galeata to the size selective predation exerted by visually hunting planktivorous fishes. After approximately one month, however, population growth rates of D. galeata and D. galeata x cucullata in the enclosures with fish converged, due to a relative reduction in the mortality rate of D. galeata. This suggests that, in the presence of fish, D. galeata may co-exist with hybrids due to a decrease in its relative vulnerability to visual predation with time. Indeed, both D. galeata and the hybrid showed strong reductions in adult body size in the enclosures with fish, but this size reduction tended to be stronger in D. galeata than in D. galeata x cucullata. In addition, turbidity increased in the enclosures with fish and may additionally have reduced the relative advantage of D. galeata x cucullata with regard to mortality caused by visual predation.
AB - Fish predation was tested as a factor mediating the coexistence of Daphnia taxa in the shallow, hypertrophic Lake Blankaart. Naturally co-occurring populations of D. galeata and the hybrid D. galeata x cucullata were subjected to different levels of fish predation in in situ enclosures. In control enclosures without fish, the largest taxon D. galeata rapidly became dominant over the intermediate sized D. galeata x cucullata, mainly as a result of higher birth rates. In enclosures with fish, population densities of D. galeata dropped relative to D. galeata x cucullata, due to higher mortality rates. These results are in concordance with the 'temporal hybrid superiority hypothesis', and can be explained by a higher vulnerability of the large and more conspicuous D. galeata to the size selective predation exerted by visually hunting planktivorous fishes. After approximately one month, however, population growth rates of D. galeata and D. galeata x cucullata in the enclosures with fish converged, due to a relative reduction in the mortality rate of D. galeata. This suggests that, in the presence of fish, D. galeata may co-exist with hybrids due to a decrease in its relative vulnerability to visual predation with time. Indeed, both D. galeata and the hybrid showed strong reductions in adult body size in the enclosures with fish, but this size reduction tended to be stronger in D. galeata than in D. galeata x cucullata. In addition, turbidity increased in the enclosures with fish and may additionally have reduced the relative advantage of D. galeata x cucullata with regard to mortality caused by visual predation.
KW - Daphnia temporal hybrid superiority hypothesis fish predation co-existence life-history variation species complex interspecific hybridization galeata-mendotae populations consequences adaptation zones lakes Marine & Freshwater Biology
U2 - 10.1023/a:1024656602248
DO - 10.1023/a:1024656602248
M3 - Article
SN - 0018-8158
VL - 500
SP - 83
EP - 94
JO - Hydrobiologia
JF - Hydrobiologia
IS - 1-3
ER -