If you’re at ESA @ecologicalsociety.bsky.social 2025 in Baltimore, come check out my talk about population dynamics and the geographic range limits of a coastal dune plant! Tomorrow (Wednesday) at 8:45am in Hilton 5!

Undertook a side-quest during fieldwork to search out an alpine sorrel population in the Lewis Hills on the west coast of Newfoundland! One of the coolest and most beautiful overnight trips I’ve ever done.

In all, this suggests that variation in patch dynamics (particularly inter-patch dispersal/establishment) may be responsible for dwindling occupancy towards the range limit, supporting the metapopulation hypothesis in this system.

If you've made it to the end, here's some bonus dune pics: (9/9)

Lastly, we found measured occupancy of plots declined towards the range limit - as we would expect (left). Further, this decline in occupancy is closely matched by the decline predicted by incorporating our estimated rates of colonization and extinction into a metapopulation model (right). (8/9)

Second, we found the likelihood of colonization and extinction were predicted by habitat and population structure. Colonization was greater at plots with more suitable habitat and that had greater local abundance (i.e., abundance of nearby plots), possibly due to higher propagule pressure. (5/9)

First, we found that the likelihood of patch colonization declined substantially towards the species' northern range limit, while extinction of occupied patches increased non-significantly - changes that we might expect from the metapopulation hypothesis for range limits. (4/9)

To test this hypothesis, we looked at coastal dune endemic Camissoniopsis cheiranthifolia, and hiked the northern ~900 km of the species' distribution to visit several thousand plots across a multi-year survey. At each, we measured patch occupancy and abundance of this short-lived perennial. (3/9)

Yesterday, I presented a poster at MUN’s Biology Symposium, where I chatted about our approach to understanding density-dependent fitness towards elevational range limits. I had a ton of fun, many valuable chats about field methods, and am grateful to have been awarded best poster presentation!

Spent a couple days this week scouting out potential field sites at Gros Morne National Park. The snow was magical!

Bonus duckweed pic if you made it this far:

Lastly, we found no evidence for the gleaner-opportunist trade-off. We expected gleaner genotypes (those with a lower R*) to be worse off at high resource concentrations (ie., have a lower max growth rate), and that this relationship would be weakened under stress, but these patterns didn’t emerge.

We found only a small amount of variation in R* across genotypes, and this variation was further suppressed under stressful temperatures.

This may point to a constrained capacity for selection to act on R* in stressful conditions.

We found that R* for nitrogen, the minimum resource level required for positive population growth, was higher under stressful conditions.

In other words, duckweed populations needed a greater concentration of nutrients to grow when it was uncomfortably warm.

Had so much fun today representing @munlgeog.bsky.social at the virtual ACAG conference! I discussed some preliminary results from a project with @carissabrown.bsky.social, where we’ve found unusual post-fire black spruce recruitment patterns at the south coast of Labrador 🌱

A very (very) frigid mid-November dip when the sun peaks out in NL

Post a picture you took (no description) to bring some zen to the timeline

Hi everyone! To introduce myself on BlueSky after moving over from the bad place: my name is Graydon (he/him), I’m a grad student currently in Newfoundland, and I’m interested in plant ecology, species’ distributions, and range limits.

I’d love to connect with other #ecoevo folks on here!