I wrote a month ago about bioblitzes, events that put amateur naturalists into the field for an intensive survey of the biodiversity of a particular place. My goal then was partly to spread the word on a special event: the first-ever Inter-Island BioBlitz, pitting Martha’s Vineyard against Nantucket in a two-week contest to see which island could document the most biodiversity.
The event, first proposed by our friends at Nantucket’s Linda Loring Nature Foundation, ran from July 24 through August 7. The winner was announced on Friday, August 14. Nantucket, despite marshaling fewer participants, logged more observations than the Vineyard did: 8,373 to 8,113. But the more important competition for most species, although excruciatingly close, ended with Martha’s Vineyard triumphant after multiple lead changes: 1,706 to 1,677.
Regardless of which island won, the event was, in my view, a startling success. Its goals, in addition to a little friendly competition, included encouraging use of the iNaturalist “community science” platform and generating simultaneous snapshots of the wild plants and animals active on each island. Everybody won big in all of those areas.
Across the two islands, an impressive 268 individual observers contributed. Their efforts generated 16,529 observations, and documented a total of 2,835 species. On the Vineyard, iNaturalist activity was about eight times the level seen during the corresponding two weeks last year, suggesting that adding an element of competition inspired many new users to get active, and experienced users to crank up their production. The intensive effort documented many rare and unusual species, including many regional first records.
My own experience of the event was intense. Of course, I love observing nature under any circumstance, and do so happily for long hours under any conditions. But while I don’t think of myself as a particularly competitive person, I found myself really, really wanting to beat Nantucket. And as the event progressed, I found myself working ridiculously hard to find as many species as I could, both to add to my team’s list and for my personal tally.
Conditions were challenging, with most of the BioBlitz period featuring hot and very humid weather. (Several rainy days during the event period pretty much shut down fieldwork, which at least gave everybody a little rest.) The event hit a flat spot in the year for insect activity, which is my main focus; insect numbers seem low in general this season, and the cusp of late July/early August is typically a slow period in the best of years. Very few flowers were blooming, making it hard to detect and identify plants. And with flowers being a huge attractant to insects, the paucity of flowers removed one of the most powerful methods I use to find insects.
And as always, fieldwork brought frustrations. I saw a target robber fly, Proctacanthus philadelphicus, four or five times, but never managed to photograph it. I completely missed two grasshopper species I felt sure of finding. I accidentally deleted a photo while editing it, depriving my team and myself of the bee species, Halictus rubicundus, that it portrayed. Bonehead move!
In any event, the first 450 or so species came pretty easily, but things got challenging after that. On the last day of the event, a steamy eight hours in the field netted me only 23 additional species, as new ones became harder and harder to find. I finished the event with 624 species, with Rich Couse, a colleague of mine at BiodiversityWorks, close behind at 567. But it took the most sustained, intensive bout of fieldwork that I’ve ever put in to build that total.
What did the event show us about the two participating islands? Well, the fact that we tallied a huge number of species came as no surprise, since the biodiversity of both islands is legendary. More interesting to me has been the relatively small amount of overlap in the species that the two islands found: Very roughly, a third of the total species were found on both islands, while about a third were unique to MV and the remainder unique to Nantucket.
It is going to take a while to figure out whether that pattern reflects genuine differences in the species present during the event on each island, or whether it reflects the expertise and interests of the observer corps participating on each island. My guess is that both factors played a role. But for whatever reason, it appears that, for example, Nantucket trounced the Vineyard in marine life, while we returned the favor for many groups of terrestrial insects. These two islands truly are “the same but different.”
So a lot of rumination and data analysis lie ahead. And, of course, an even more important question awaits an answer: Which island will win in 2027?
