Visit 3, Version 3

On May 3 we made the official third visit to the vernal pool we are monitoring. During this visit we are supposed to collect the frog call recorder and do the final surveys for amphibian eggs and aquatic invertebrates. At the second visit we failed to find any fairy shrimp, so I was looking forward to adding them to my crustacean life list. I was also looking forward to collecting the microSD card from the data logger we had installed on April 17 and examining two more weeks worth of data. And at the last minute I decided to bring a 24 foot-long pole and get some “aerial” photos from above the pool. By the time we left the pool to hike back to the road, I was dismayed at my lack of success at most of these goals.

Ned brought his waders and I didn’t, but somehow I was the one wading out to install the new version of the data logger. Photo by Ned, May 3, 2020.
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Vernal pool data logging

Vernal pools are little ponds which have no permanent stream entering or exiting. They fill with snowmelt, rain, and groundwater, but in droughty years they often dry out before summer’s end. These characteristics prevent fish from living in vernal pools (fish can’t get to them and fish couldn’t escape when they dry out). This allows animals with little defense against hungry fish to prosper in vernal pools, especially if they can also survive when the pool dries out.

Ned is installing the data logger on a wooden post in about 20 inches of water. There is still some ice at the edge of the pool. March 28, 2020.
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Bridgewater Hollow BioBlitz

This past Sunday, six people with smartphones and one guy with a pad of paper descended on a 350 acre property in the Green Mountains near Bridgewater Hollow, Vermont. The smartphone people used iNaturalist to document about 300 observations of plants and animals (and quite a few things that might be neither, like slime molds and fungi). The paper guy was Brett Engstrom whose list of vascular plants is probably longer than the list of all the species that everyone else compiled. 

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Arrested alder

Very few Sitka alders established during the first two decades after the retreating Muir Glacier exposed my youngest study site (Site 1) at Glacier Bay. Older sites in Muir Inlet had abundant alder plants by the time the surface was 20 years old, and it seems likely that the difference was caused by a shortage of alder seeds arriving at the young site. Today there are a few alders at Site 1, and what they have done (or not done) in the last three decades suggests a more nuanced explanation.

View from Plot 1 at Site 1 in three different years. Two Sitka alder plants visible in 1990 (ellipse) produced seeds which formed an island of alder 80 m across by 2018.

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When alder can’t keep up

The young vegetation on the north side of Upper Muir Inlet in Glacier Bay National Park is developing dramatically differently from older vegetation a few km away. Today, five decades after the retreating Muir Glacier exposed my youngest study site (Site 1) to plant invasion, it supports an open shrubland of willows with most of the ground still carpeted with low-growing Dryas drummondii. At the same age (in 1995), the next older site (Site 2) had no Dryas and was a dense thicket of 6 meter tall Sitka alder shrubs. The distinct successional pathways being followed at these sites have critical ecological differences (e.g., alder is an important nitrogen fixer) and suggest that inferring ecological change from a sequence of different aged sites in this part of Glacier Bay does not work.

Can seed rain explain this?

My favorite hypothesis to explain this is that early seed rain of alder differed between the two areas. Ice margins in Glacier Bay have been retreating to the north for almost three centuries, and invading newly exposed terrain requires that plants can migrate as fast as the ice retreats. Alder was apparently doing a good job of chasing the ice along most of Muir Inlet where my reconstructions of invasion histories at four study sites confirm that alder was an important early invader. Continue reading “When alder can’t keep up”

Vintage chronosequence

In the late 1980s, I established vegetation study plots at 10 sites along the eastern side of Glacier Bay in southeastern Alaska. These sites were more or less evenly spaced between the retreating Muir Glacier and the terminal moraine which the Glacier Bay ice had built at the end of the Little Ice Age. The youngest site had been exposed by retreating ice in 1968 and the oldest site had been exposed around 1770 soon after the ice melted back from the 1740 moraine. So on average the age difference between “consecutive” sites was about 20 years (202 years ÷ 10).

There are three approaches to learning things from this series of different aged study sites:

  1. You can assume the sites form a chronosequence so that changes inferred from the series of progressively older sites are also changes that have happened at individual sites. According to this assumption my older study sites would have passed successively through stages similar to all of the younger sites.
  2. You can be less trusting of the chronosequence and use evidence at each site to reconstruct its developmental history. This history can be compared to younger sites and to their histories to test the above assumption. Tree rings and paleoecology are potential sources of information about vegetation history at individual sites.
  3. You can wait until each site attains the age of the next older site at the time of establishment. At that time Site 1 should look just like Site 2 did when you started, and so on. If the chronosequence assumption is valid, each site will have aged predictably and you will have a new, slightly older, and now verified chronosequence. You can have some confidence that inferences about change made from that chronosequence are valid.

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Documenting Dryas

I saw Riggs Glacier on my first trip to Glacier Bay in 1984. Of the three tidewater glaciers in Muir Inlet at that time, only McBride Glacier reaches sea level today. In 1990, as one of the final field tasks for my dissertation, I established permanent study plots between Riggs Glacier and Muir Glacier. This summer Galen and I used old sketch maps to find all five of them and recorded GPS coordinates.

Lewis testing his downwind rig at Riggs Glacier. Kodachrome, July 1984

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Cairn photo

My second youngest study site at Glacier Bay is on a bench of outwash about 150 feet above Muir Inlet. Before alders covered the young surface in the mid 20th century, the bench offered a good view of the retreating face of Muir Glacier to the north. William O. Field established a photo station there maybe in the late 1940s and marked the spot with a cairn assembled of several large rocks. I found the cairn in 1988 when I set up my study plots in a dense thicket of alders.

A photo station cairn built by William O. Field near one of my study plots. This might be Field’s station “6A.” Kodachrome, May 1995

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Shelf portrait

It was not easy to find a photo of these bookshelves as they were installed in my parents’ house. The shelves were behind a table and hard to photograph, and they were also not very photogenic. I thought they were cool and modern in the sixties, but I never thought they were important (I do now). The shelves are probably in the background of some other photos, but this one from 1972 was the first I came across and is certainly more interesting than the rest. Many of the books in this shot are still on these shelves.

This is probably about a 10 second exposure. I might have had someone turn out the room light while I moved between positions. Panatomic X film, Fall, 1972.
This is probably about a 10 second exposure. I might have had someone turn out the room light while I moved between positions. I used Panatomic X, a very slow (ASA 32), very fine grained film. Fall, 1972.

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Hot and sweet

It's easy to grow lots of peppers even in Vermont. Jalapeños are in the upper left corner.
It’s easy to grow lots of peppers even in Vermont. Jalapeños are in the upper left corner. November 3, 2014

While I was putting a finish on the first pint of maple syrup of the season today, I also processed the peppers from last season. On a visit to New Orleans in November my friend Shannon introduced me to the idea of making Louisiana hot sauce. I had never considered doing this, but I had just harvested several gallons of Jalepeño peppers, so when I returned to Vermont I stemmed and seeded all the bright red ones, chopped them up and covered them with brine. The jar quickly started to produce bubbles of CO2, so I added a bubbler to let the gas escape but keep air and bacteria out. You can see it working in the video below.

Today I pureed it in the blender and added several tablespoons of red wine vinegar. Instead of just bottling it, I boiled it first. I guess that destroyed all the probiotic benefits the fermentation might have added, but I thought it might keep longer. I should have bottled some without boiling to see how it did. Continue reading “Hot and sweet”

The KAPtery has moved

MiddBann2k1Today the KAPtery moved to its own site: KAPtery.com. This frees up my personal site (fastie.net) for other things, but most importantly offers you a much better place to learn about 3D printed camera rigs for aerial photography. The commerce part of The KAPtery should also work better — buying kits and parts should be easier and more secure. Continue reading “The KAPtery has moved”

Gas Ice Bait Beer

Everything you need in Chauvin, Louisiana.
Everything you need in Chauvin, Louisiana.

The levee of Bayou Petit Caillou supports the long strip of houses that is Chauvin and Cocodrie, the narrowest towns I have ever seen. Way down delta in Louisiana, you are either on the levee, in the bayou, or somewhere out in the salt marsh. For exactly 100 years, Cecil Lapeyrouse’s Grocery has been on the levee. Today most of the houses are seasonal, and the store gets by with business from people coming down to shrimp or fish or have fun. We stopped by on our exit from the LUMCON Marine Center in Cocodrie where Public Lab held its annual meeting. That had fallen into the fun category. Continue reading “Gas Ice Bait Beer”