Identifying consumer-resource population dynamics using paleoecological data

Area of Science:

• Ecology
• Paleolimnology
• Population Dynamics

Background:

• Cyclic population fluctuations suggest species interactions but are hard to identify with single-species data.
• High-amplitude population cycles in Lake Mývatn midges have been circumstantially linked to midge-diatom interactions.

Purpose of the Study:

• To investigate the consumer-resource interactions driving irregular, multigeneration cycles in the Lake Mývatn midge population.
• To provide the first paleoecological evaluation of specific trophic interactions underlying high-amplitude population fluctuations in lakes.

Main Methods:

• A paleoecological approach using sediment cores from Lake Mývatn.
• Reconstruction of 26 years of midge dynamics (egg remains) and algal groups (diagnostic pigments).
• Statistical analysis accounting for autocorrelation and measurement error in paleoecological data.

Main Results:

• Diatom abundance (diatoxanthin) increased when midge abundance (egg capsules) was low, and vice versa, indicating a consumer-resource relationship.
• No similar patterns were found for cyanobacteria or cryptophytes.
• A weaker pattern was observed for total algal abundance (β-carotene), with diatoms as the dominant contributor.

Conclusions:

• The study provides strong evidence for consumer-resource interactions between midges and diatoms as the driver of midge population cycles in Lake Mývatn.
• This research validates the use of paleoecological methods to uncover specific trophic interactions in lake ecosystems.
• Findings contribute to understanding the mechanisms behind population dynamics in fluctuating ecosystems.