Environmental response: Temperature

[Dries Lorré]

Hi all,

I have a question related to Environmental response functions and Temperature time series.

1) The problem:

We have monthly temperature time series, however, when linking this to the environmental response functions, some species show quite high biomass fluctuations -on a early basis- (due to the wide range of winter to summer water temperatures within one year). 

However, when using the yearly average temperature, the model misses some of the observed biomass trends as the average temperature is always rather close to the optimum response of the species. It is clear that, for instance, years with warmer summers result in a larger negative foraging response. Such trends are missed when forcing yearly average temperatures.

2) The questions:
Is it common practice to force only summer or winter temperatures -for the whole year-? (This seems wrong to me, since this approach assumes the consumption rate is affected for the whole year, which is not really the case)

--> Doing so in the model does however result in a better fit to the data....

An other approach might be to calculate an "average response" for each functional group based on all monthly temperature data for each year, rather than calculating the response of the average temperature in one year. Years with more extreme summer temperatures might therefore result in bigger consumption compensations in species such as cod who love colder water. Has this been done before? And does this approach make (biological) sense? I do not seem to find a lot of information in literature.

I would love to hear some ideas/opinions on this matter.

Thanks!

Warm regards,

Dries

[Riikka Puntila]

Hi Dries!

I have gone around the seasonality response by having time series and responses for different times of the year for different groups (aka quick and dirty approach). For example I have annual time series of mean spring temperature and some groups have environmental responses to that. Similarly I have time series for mean summer temperatures and some groups responding to that. 

I am also working in a seasonal system (Baltic Sea) and I’d be interested to start moving my model towards monthly time steps (which would allow having ice in Ecospace and other cool things). I half jokingly tried with monthly time steps too and also experienced quite large fluctuations. 

I’m also interested to hear how others have solved the problem.

Best regards,

Riikka Puntila-Dodd

Åbo Akademi University 

On 18. Oct 2024, at 17.02, Dries Lorré <dries...@gmail.com> wrote:

Hi all,

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