Tweet roundup. Ecology (EES-152), Fall Semester 2017.

Some of my favorite course-related tweets in Fall 2017…. another semester of fun!

Advertisements

Observing the observer

It is starting to feel like fall, although there are not many colors in the trees yet.

The colors were vivid on the day pictured in the painting below, and I fondly remember a really great hike through a hemlock-dominated ravine as part of this camping trip a few years ago. The painting was an attempt to capture a moment that I spent watching my daughter as she sketched in her notebook.

observing

Observing the Observer. Oil on Canvas. Finished May 2017.

State of the Lehigh Experimental Forest, 2017

20170911_150231General ecology (EES-152) students have finished resurveying a portion of the Lehigh Experimental Forest, assessing changes in species mortality and recruitment since 2013. A total of 1174 trees were inventoried and measured from across the forest the last two years, representing more than 1/2 of all trees originally tagged in 2013. In the four  years since 2013, 167 of these 1174 trees have died (~14%) and only eleven new trees have established in the study area (<1%).  Data for the dominant tree species are shown in the plot below.

LUEF 2017

Abundance, mortality, recruitment, and the net percentage change of tree/shrub species in the Lehigh University Experimental Forest, 2013-2017. Relative frequency data are from 2013 (M. Spicer, MS thesis 2014) and indicate the percent of each species present (based on a total of 1174 trees). Total mortality and recruitment for each species with greater than 10 individuals are shown as percentages. Species are arranged from those undergoing substantial declines in abundance at the top to those that have increased in abundance on the bottom.

 

We will use these data to discuss processes controlling forest dynamics as the semester progresses.  However, for now, students should answer the following questions:

  1. What factors might have caused the differences in mortality among species?
  2. Develop a hypothesis to explain the lack of recruitment for most tree/shrub species. Then do some research on the two tree species that have successfully recruited and those species that have not. Are there species traits that are common to successful and unsuccessful recruiters? Are these traits consistent (or inconsistent) with what you might predict from your hypothesis?
  3. What does the pattern of mortality and recruitment suggest about the future of the Lehigh Experimental Forest? Assuming the rates of total tree recruitment and mortality are representative of future years, when will there be less than 100 trees in this forest?  In 2013, there were ~2000 trees in the forest so you can use that as your starting number. Show your work and describe how you arrived at your estimate.  Do you think this scenario is likely?  Why or why not?

The Tangled Bank Gets A Sign!

The Tangled Bank, an ecologically and historically interesting spot on the Lehigh University campus (see here for details), gets some well-deserved recognition with a sign!

Invasion confirmed. Water lettuce and water hyacinth overwintering in Pennsylvania.

Last September, two invasive aquatic plants, water lettuce (Pistia stratiotes) and water hyacinth (Eichhornia crassipes), were discovered in the Lehigh Canal in Bethlehem PA.  Both species are floating plants, like duckweeds but much larger, and they often grow in dense mats in tropical and subtropical regions. Although this was the first confirmed occurrence in natural habitat within Pennsylvania, both species are sensitive to freezing temperatures so they have not not been regarded as major threats in the Northeast. A description of the discovery of these populations and some background on the species, including a discussion of recent work suggesting that the overwintering potential may be greater than previously thought, can be found in my post from last year (New invaders in the Lehigh Valley? Or Just Summer Visitors?).

The discovery last year prompted several questions. In particular, are these populations really persisting from year-to-year and therefore surviving freezing temperatures? I suspected that they were introduced last summer from someone’s pond and that they would not survive the winter. However, the winter was mild and the recent discovery of some overwintering populations in the lower Great Lakes gave me pause. I road my bike along the canal towpath last week to have a look.

I was wrong. Both species have overwintered. A harbinger of things to come?  Below are some pictures, and I’ll update this post with more later in the summer.

20170710_161734

Water lettuce survived the Pennsylvania winter in the Lehigh Canal. 10 July 2017.

20170710_161837

Water hyacinth also survived the Pennsylvania winter in the Lehigh Canal. 10 July 2017.

20170710_162915

Larger clump of water lettuce in the middle of the canal. 10 July 2017.

20170710_162349

Only a little bigger than the duckweed, you can see the light-green colored water lettuce in this image. Given the small size, I suspect it came back from seed. 10 July 2017.

What’s in a name? Something (completely different) to be said about taxonomic nomenclature

A fun post on inspiration for species names….in testate amoebae!

From inside the shell

By Edward A. D. Mitchell,

Laboratory of Soil Biodiversity, University of Neuchâtel, Switzerland

With the advent of high throughput sequencing, estimates of global diversity are being totally revised.  For us protistologists – arguably much more importantly – so is the picture of how diversity is distributed among the different branches of the tree of life. The image that emerges is one that shows a huge unknown diversity among protists, at all levels, from major groups (i.e. “environmental clades”) and within known groups (i.e. from more or less divergent groups to complexes of cryptic and pseudo-cryptic species). This is fascinating and to say the least mind-boggling and a much welcome development for making a case about the need to study protists more intensively. It is indeed impossible today to ignore this diversity and the many functional roles that protists play in all ecosystems.

But this unknown diversity also calls for a…

View original post 813 more words

Another spectacular Laguna Negra

20 Jan 2017

20170119_100720

The mountain above Laguna Negra near the town of Mongua. If you zoom in on the ridgeline you will see our paramo indicator species, Espeletia. There was clearly a different species of it growing around this lake, with smaller composite flowers arranged in clusters.

img_1218

“Black Lakes” in Colombia appear to be about as common as “Mud Lakes” in Minnesota. This was the second Laguna Negra that we have visited, and it was located about an hour and a half drive northeast from Sogamoso.

Today, we were accompanied by Felipe Velasco again, although this time instead of driving south toward Lake Tota we headed northeast toward the town of Mongua.  We are extremely grateful for the time that Felipe has devoted to our efforts, as we would have had a difficult time finding these sites without him and it was reassuring to have a local person along. Our goal today was to explore and hopefully collect a core from Laguna Negra, a lake located in a different sort of paramo ecosystem. The drive was quite different than previous days, because we were able to see a much more industrial area of Boyaca. Between the cement factories and the steel mill, the pollution levels were quite high; in fact, much of the drive to Mongua smelled of a fragrant mixture of burning coal and diesel, and when we ascended the mountain above Mongua we observed a thick layer of smog in the valley. However, it was fascinating to see a fully functional steel mill, as gave me an appreciation of what Bethlehem Steel in Pennsylvania must have been like when it was operational. We observed many small family-owned coal mines along the road near Mongua, as this is the primary economic activity in this region.

20170119_105539

Laguna Negra, with abundant Azolla (mosquito fern) growing in the littoral zone along with a diverse array of submerged aquatic plants.

Laguna Negra and the surrounding landscape was spectacular, and pictures really can’t convey the natural beauty of this place. While Jason and Jaime took measurements of the depth profile of the lake, I had the opportunity to hike around the lake margin. Unlike other lakes that we have visited, the lake margin was not peatland. Hypericum (St. John’s Wort) was common along the lake edge, along with a  number of Carex species, and bright red Azolla grew in the littoral zone along with submerged aquatic plants like Myriophyllum. Inflow into the lake comes in the form of a spectacular waterfall, with abundant mosses and ferns growing adjacent to the waterfall in the perpetually humid environment.

img_1231

Myriophyllum growing in littoral zone of Laguna Negra.

20170119_105814

Hypericum growing along the edge of Laguna Negra.

The lake was about 9 meters deep with at least 3 meters of sediment, so we inflated a second boat, set our anchors, and commenced sediment coring. Mark Brenner and Felipe Velasco observed from shore, taking pictures of the coring process.  We obtained several meters of mud, and once again we carefully kept the upper drive containing the mud-water interface upright on the trip back to Finca SanPedro.

dscn2199

Jaime Escobar, Jason Curtis, and myself collecting a sediment core from Leguna Negra.

img_1274

Inside of the church in Topaga. Beautiful gold-plated structures and artwork decorate the interior.

On our way home we stopped in Mongua for some delicious empanadas and then went further down the road to Tópaga to take a look at the church on the main square. The Tópaga church is over 400 years old, and the inside is ornately decorated in gold. Colombia has abundant gold; in fact the yellow in the Colombian flag symbolizes the tremendous gold resources. This church in Tópaga is also probably one of the few churches that not only has artwork incorporating Jesus, the disciples, and other typical biblical representations, but also the devil. Yes, Lucifer himself is on a beam in the ceiling near the front of the church, directly center.

img_1276

The devil decorates the main beam on the ceiling of this church in Topaga.

Our fieldwork is now complete. Tomorrow we will ship samples and cores from Sogamoso and then drive down to Bogota to pick up samples from our work in Manizales and prepare to depart on Sunday.  This trip has been an amazing experience, and I feel extremely lucky to have had the opportunity to explore this fascinating country and see its amazing natural beauty. I am excited about this new collaboration, and the potential to develop long-term perspectives on water availability and ecology of the critically important paramo regions.

I sincerely thank Jaime Escobar for making this all happen.  And I especially thank him for the doing all the driving!

Coring Lake Aquitania

18 January 2017

20170118_142307

Panoramic view of Aquitania Lake. Notice the blooming Espeletia.

img_1204

After we finished coring, our PVC and wood was taken away by a man and his horse (and his dog). I’m sure it will be put to good use.

We traveled back up to Aquitania Lake today, managing to navigate back to it without the help of Felipe. We spent the day successfully collecting the full sediment record from the lake, over 7 meters of mud.  While Mark, Jason, and Jaime did the coring, I collected plenty of surface samples from the surrounding peatland. Part way through the coring, we had a Colombian visitor who came to the lake on his horse to ask us what we were up to. He seemed amused by our activities. Not wanting to strap all the PVC and wood back onto the car, we offered it to him.  He was thrilled to take it, and we gave him rope so that he could strap it all together and then tie it to his horse.  I was really impressed with his rope tying ability, and although the horse did not seem particularly happy about the situation, it carried all the pipe and wood away.

Anyone know what kind of bird is in the video below?  A sandpiper of some sort?

A collage of some of the interesting plants observed around the margin of the lake:

After a quick dinner in Sogamoso, we returned to Finca SanPedro where Mark Brenner gave a public talk highlighting the paleoclimate work that he has conducted with Jaime, Jason, and others in Latin America.  Impressively, Mark gave the talk in both English and Spanish! I’m really going to have to learn some Spanish before my next trip to Colombia.

p1430410-1

Mark Brenner gives a public talk at the Finca SanPedro.

%d bloggers like this: