Import biomass: Cowichan 2015-2021

[KW529]

Done

[KW529]

Sent 11-24-2021:

Hi Mendy and Kate,

I hope you are both surviving what feels like this never-ending pandemic. I was sorry to miss Kate's talk earlier this fall, but my grad student who could attend said she really enjoyed it. I have a grad student (Lauren Smith) who is analyzing all the years of biomass & community composition data from our site, and adding in an insect sampling component for her MSc thesis.

In doing so, we have gone back to re-examine some of the old biomass samples that we kept. I am embarrassed to say that there are some problems with the bryophyte & shrub contributions. In the early years, the student helpers collecting the data most likely misinterpreted the protocol - what we have for sure is all above ground standing crop, but not separated out the current year's growth (they read the part about harvest all above ground biomass, but not the part about current year's growth). Bryophytes were uniformly difficult to collect, and we have both current & past year's growth mixed together, and sometimes other detritus that was difficult to remove. The summer undergrads started going back through the samples we do have and re-weighing them. We have already done the same for the shrub samples (discarding the large woody material).

What this means is that for 3 years where we saved the biomass, we have the actual (corrected) ANPP, and for the other years, we can apply a correction (mean difference between actual and corrected from other years). In Lauren's analyses, we were relieved that the relationship between soil moisture and productivity did not change with the shrub corrections (she excluded moss, since most of her analyses were focused on herbivores).

Let me know how it would be best to supply the corrected data. And maybe this will help our site be not a total outlier in the bryophyte category?! (although it's of course still way mossier than any arid grassland).

cheers,

Jennifer

From Kate:

Hi Jennifer,

No worries, and thanks so much for letting us know! It would be great if you could send the updated ANPP and let me know which years have been updated so I can correct them in our database.

Best,

Kate Wilkins Pronouns: She/her(s)

[KW529]

Sent 03-07-2022:

Hi Kate,

here's a CSV with the corrected biomass. Thanks so much for your patience!

We reweighed samples from 2017, 2019, 2020 and 2021 - the new biomass are given here. We removed secondary biomass from shrubs, and did our best to do the same for the bryophytes.

For the samples we no longer have, we corrected as follows:

For shrubs: woody material accounted for approximately half of most the large shrub biomass samples from those years, we adjusted for this by halving the collected shrub biomass when it was greater than 5 g/m2 in those years

For bryophytes: growth from previous years plus other things stuck to the moss were removed. I used a correction factor of 0.2 for samples that were not reweighed.

I added corrected or reweighed to the notes column.

Please let me know if you have any questions! thank you again for including our data.

cheers,

Jennifer

[KW529]

From Kate, 03-07-2022:

Hi Jennifer,

Thanks so much for taking the time to reweigh and send us your data! I'm sure that was a lot of work, and we really appreciate it.

Just to double check, are all values aboveground net primary production and represent g/m^2?

Best,

Kate Wilkins

[KW529]

03-07-2022:

Hi Kate,

Oh - good point. No! They are for g/0.2m^2 (we weighed the biomass from the 20 cm x 1 m strip each year). What is the best practice for this for the IDE?

And yes, all values are as close as we could get to above ground ANPP (lots of tiny things - so we did the best we could to separate out the dead stuff, and that from previous years - and yes, the reason we had to reweigh was to pull out previous years’ productivity from mosses & shrubs)

They probably spent far too much time doing this, but the samples of moss look like only little green bits now, what we estimated was one year’s growth….

cheers, Jennifer

[KW529]

Corrected data entered.

[KW529]

Hi Jennifer,

Thanks again for sending your updated data! I just noticed a duplicate value in your 2020 biomass data for Bryophytes. Could you clarify which is the correct value? Thanks!



site | plot | subplot | taxa | mass | date | note_biomass -- | -- | -- | -- | -- | -- | -- Cowichan | 15 | A | Bryophyte | 8.737 | 6/12/2020 | reweighed Cowichan | 15 | A | Bryophyte | 9.51 | 6/12/2020 | reweighed

Cheers,

Kate Wilkins

[KW529]

Hi Kate,

You're a hero for catching mistakes like this, and also, thank you for your patience!

That first value (8.737) should be in plot 14.

As I'm looking a the data again, I do wonder about the 'tree' category we've used - those were tree seedlings - and they nearly all die before the next growing season. Suggestions?

cheers,

Jennifer

[KW529]

Hi Jennifer,

No worries- that's my job 🙂. Thanks for the clarification!

For the tree seedlings, would you say that they were the current year's growth? We've been including a woody category in our ANPP estimates when sites indicate that they are current-year's growth.

Best,

Kate Wilkins

[KW529]

Corrected duplicate biomass value in raw csv and in SQL

[KW529]

oh for sure the tree seedlings are from the current year - not at all woody yet! (babies, really - they germinate, grow a little, and are dead by the next year)

cheers,

Jennifer