and take-home messages...
Conclusion.
As a quick recap of what was expected from the data;
1. Positive relationship between temperature and insect abundance
2. Negative relationship between precipitation and insect abundance
3. Higher magnitudes of changes in Lepidoptera rather than Coleoptera
A quick recap of what was indicated by the data;
Haliplus immaculatus, a species counted 6 times at the Zoological Museum between 1992-2009 (image link)
Habrosyne pyritoides, a species counted 22 times at the Zoological Museum between 1992-2009 (image link)
Yearly Counts
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boom-bust cycles visible for most Families
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stronger cycles within highly abundant groups
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strength of boom-bust cycles have a possible explanation in the common life strategies of each Family
Yearly Counts
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no apparent annual trends in insect abundance
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explanations for the lack of annual trends could include the dispersal abilities of moths/butterflies which allow them to move away from sub-optimal climates much easier
Temperature Trends
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insect abundance is higher when the months of May-August are warmer
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a potential influence of warmer November temperatures on higher insect abundances
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temperature trends explained by physiological optimums and timing of highest insect activity
Temperature Trends
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no difference in sensitivity compared to Coleoptera
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insect abundance is almost always higher when temperatures are warmer
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temperature trends explained again by dispersal abilities of this group
Precipitation Trends
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a wet June followed by a dry July would result in the highest insect abundances
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a potential influence of dryer Novembers with higher insect abudances
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lack of more conclusive precipitation trends potentially explained by masking by other variables within the city
Precipitation Trends
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no difference in sensitivity compared to Coleoptera
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dryer Julys and Augusts result in higher insect abundances
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lack of more conclusive precipitation trends potentially explained by masking by other variables within the city
What are the implications of this?
The ultimate value of gathering these results was to contribute to the ever-growing knowledge on insect responses to climate change. Long-term and population-level knowledge, such as the information found in this project, is less common within the literature (Kocsis and Hufnagel, 2011; Halsch et al., 2021). With our ever-changing climate, a comprehensive understanding of how our insect communities will be affected is essential.
The results from this project show that Copenhagen beetle and moth communities are sensitive to increases in temperature but not as much to changes in precipitation. In addition, the summer months' temperature and precipitation levels seem to have the most influence on the insect abundance within the city. The potential November climate correlations within the Coleopterans are interesting and should be further explored.
This information tells us that the rising temperatures due to climate change, especially during the insect-active summer seasons, are the largest threats to keeping the insect communities within Copenhagen balanced. Insects can be both beneficial and detrimental to humans and our ecosystems, and so the socioeconomic implications of these results remain unclear. Further work should continue to look at different climate variables in different regions of the world.
Arctia caja, a species counted 4 times at the Zoological Museum between 1992-2009 (image link)
Amphimallon solstitiale, a species counted 134 times at the Zoological Museum between 1992-2009 (image link)
Limitations
The main limitation of this project was the time available to complete this project. The dataset was extremely comprehensive and had there been infinite time allotted, more in-depth analysis with more climate variables could have been completed. As such, limitations in the scope of this project revolve around;
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the removal of less abundant Families from the analyses: perhaps rare species should be our main concern?
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the lack of consideration of yearly trends in the correlation analyses: how would the boom/bust patterns further influence the results?
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the lack of ability to make socioeconomic conclusions from the results: the impact on all insects was explored, but how would this affect ecosystem functioning and anthropogenic life?