Image: Blackpoll warbler (one of the declining species), © Simon Barrette CC BY-SA 3.0 via wikimedia.org
You saw the headline (and maybe you read the study): three billion lost birds. Three billion fewer birds in North America than there were in 1970. It’s eye-catching, isn’t it? There are (as is usually true) some reasons to interpret the result with nuance, but that isn’t my point today – Brian McGill has covered that with admirable thoroughness over on Dynamic Ecology. Instead, I’ll dig briefly into what the study told me about my own ignorance. Three billion is the change. How many birds remain – and could I have answered that question before seeing the study? Continue reading
Image: “Beautiful vineyard” by Sasmit68 via wikimedia.org, CC BY-SA 4.0
Last week I raised the apparently-dumb but actually rather interesting question of why humans consider flowers to be beautiful. Today, another question about beauty, this time with (I’m afraid) really unfortunate consequences. Have you ever heard someone talk about how beautiful a vineyard is? Have you ever been that someone? An awful lot of us would answer “yes” to both questions – and that’s a real problem for conservation.
It isn’t just vineyards, of course, and I’ll get to my broader point, but first I should back up my claim that humans think vineyards are beautiful – and that we shouldn’t. Continue reading
Figure: Time series for two populations, each fluctuating in size. At time zero, I start a long-term study, and can choose either of the two populations (open circles). At some other time, I recensus (closed circles). Red arrows show net population change.
On any given day it’s hard not to notice another headline about a population in decline. Amphibians are in decline, songbirds are in decline, bumblebees are in decline, fish stocks are in decline. Nature is under relentless human pressure, both direct and indirect, and before I proceed to make my point today, I need to be very clear that this pressure is real and severe and I don’t doubt for a moment that it’s driving down population sizes of many, many species.
But there’s a very simple but pervasive statistical problem with the data behind population declines. Continue reading
Image: Skillet Clubtail dragonfly, by David Marvin (CC BY-NC-ND 2.0)
This year in my 3rd-year Entomology course, we introduced a new student assignment: to write a blog post about an insect of conservation concern in Canada. (I say “we”, because most of the credit goes to my TA and PhD student Chandra Moffat. I’ll link to some of the resulting posts below; but first, a few thoughts. Continue reading