Is having a bio blitz at the end of June one year, and then beginning of August the next year too much of a significant difference in time of year? I’m in the Twin Cities area in Minnesota, and work for an organization that plans for an annual one day bio blitz event each year.
I know that data should generally be collected around the same time every year, however the organization I’m with has do deal with different funding cycles year to year for this particular event/program.
I would say yes, there will be a noticeable difference. A quick query yielded 5685 species in your region in June, while there were 5302 in August. July had 5716. For insects and arachnids, the number were ~3000 for June and ~2500 for August. Of course the end of June and early August are closer than the months as a whole, and you’d get a typical “summer bioblitz” variety, but they won’t be the exact same community of insects and plants due to the month difference in time.
It depends what your goal is. Is the intent to be able to scientifically and rigorously compare the results in one year to the other? Then the difference in time to this degree would cause issues. But having a bioblitz at different times of the year in different years will allow you to find more of the diversity at a site which can also be very valuable (some species will be active IDable during one period that aren’t during the other).
And of course, a goal of most bioblitzes is engagement, so this should be taken into account as well. For some attendees, having a set time each year may help them plan to attend, but changing the time may allow you to incorporate people that couldn’t attend at the other time, etc. For instance, there is a bioblitz near me that is always on the same weekend when I visit family in the summer. I’d really like to go but never can because of that conflict.
The Great Southern Bioblitz moves across months from year to year. Giving countries with different biogeography a turn. GSB began to give us a chance to observe our spring.
October 24th-27th 2025
September 20th-23rd 2024
24 - 27 November 2023
etc
I don’t have an answer but I live in the Twin Cities and I’m always up for a bioblitz (depending on the time and location). Feel free to tag me if you set one up.
That said, I am mostly interested in a bioblitz where the true intention is to document as many species as possible. More and more, I’m running across advertised ‘bioblitzes’ where the main intention is to run a casual naturalist event and use iNat and the spiffy label of bioblitz to get people interested. Those seem clearly not to fuss much with trying to truly assess the organisms on a property.
And, although I can’t give a scientific/professional answer for your question, I think the difference in a few months can make a huge difference in what gets observed (in our area, at least).Having a bioblitz in different months in successive years would be a good option if you want to get a handle on ‘everything’ that exists in an area. If you want to compare numbers or phenology from year to year, then I guess the same time each year would be better.
The City Nature Challenge also varies slightly from year to year
2024 26 - 29 Apr (this year they split to TWO umbrella projects)
2023 28 Apr - 1 May
2022 29 Apr - 2 May
and so on