Characteristics of consumer trophic resources for Waikato shallow lake food webs
2019
Collier, Kevin J. | Garrett-Walker, Jeremy | Özkundakci, Deniz | Pingram, Michael A.
We characterised the quantity (mass per unit area or volume), quality (cabon:nitrogen ratio) and enrichment (δ¹⁵N) of basal food resources and benthic macroinvertebrates in six shallow lakes in the Waikato region, New Zealand, to elucidate patterns related to lake type (peat, riverine), habitat (littoral, mid-lake) and enrichment status (Trophic Level Index >6 or ≤5). Total seston dry mass was dominated by fine material that was correlated with chlorophyll a concentration. Seston was a higher quality food resource than benthic particulate organic matter which had higher biomass overall in littoral than in mid-lake habitats. Biomass of Chironomidae was highest in the less-enriched peat lakes, possibly due to clearer water supporting benthic algae in shallow littoral areas. Our results highlight the potential role of multiple bottom-up influences on shallow lake food webs. The more abundant and higher quality pelagic food resources in highly enriched lakes may have implications for resilience to non-indigenous fish invasion.
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