Tag Archives: biodiversity

Aquatic Invertebrates: Why You Should Give a Dam

Rivers are ecosystems that attract and maintain a diversity of organisms. Fish, birds, mammals, plants, and invertebrates live in and around rivers. Have you considered what services these groups of organisms provide to the river ecosystem? For example, river invertebrates provide numerous ecosystem services:

Dragonfly larvae caught in in the waters of a small stream flowing into the Grand Canyon.

  • Insects and mussels improve water quality by fixing nutrients, such as those from agricultural runoff.
  • River invertebrates are food resources for fish, bats, birds, and other terrestrial organisms.
  • Grazing insects can control and/or stimulate algal growth.
  • Mussels can help to stabilize the bed of the river.

High school students are the best helpers for sampling aquatic insects!

And the list continues. These invertebrates have adapted to the native conditions of their river ecosystem, and major disturbances, such as a change in the flow of a river from a dam, can change the community of organisms downstream. If dams decrease the diversity of invertebrates downstream, then they may also decrease the diversity of ecosystem services offered by the invertebrate community.

Our guest this week, Erin Abernethy PhD candidate from the department of Integrative Biology, is investigating the community structure (or the number of species and the number of individuals of each species) of freshwater aquatic invertebrates downstream of dams. Specifically, Erin wants to know if invertebrate communities near dams of the Colorado River are different than those downstream, and which factors of dams of the Southwest US affect invertebrate communities.

Getting to field sites in the Grand Canyon is easiest by raft! It’s a pretty float, too!

Erin’s dissertation also has a component of population genetics, which examines the connectivity of populations of mayflies,populations of caddisflies, and populations of water striders. The outcomes of Erin’s research could inform policy around dam operation and the maintenance of aquatic invertebrate communities near dams.

“One must dress for sampling success in the Grand Canyon!” said this week’s guest, Erin Abernethy, who is pictured here.

Growing up, Erin participated in many outdoor activities with her parents, who are biologists. She became interested in how dams effect ecology, specifically fresh water mussels, doing undergraduate research at Appalachian State University. After undergrad, Erin completed a Master’s in Ecology from University of Georgia. She was investigating the foraging behavior of animals in Hawaii. This involved depositing animal carcasses and monitoring foraging visitors. Check out Erin’s blog for photos of these animals foraging at night! Erin decided to keep going in academia after being awarded a Graduate Research Fellowship, which landed her a position in David Lytle’s lab here at Oregon State. After she completes her PhD, Erin is interested in working for an agency or a nonprofit as an expert in freshwater ecology and the maintenance of biodiversity in freshwater ecosystems.

 

Tune in at 7 pm this Sunday February, 25 to hear more about Erin’s research and journey to graduate school. Not a local listener? Stream the show live.

Unearthing the Unseen: Identifying drivers of fungal diversity in Panamanian rainforests

When our roommates or family members get sick, we try to keep our distance and avoid catching their illness. Plants get ‘sick’ too, and in the natural world, this may actually explain the coexistence and diversity of plant species that we see.

Coexistence

Species coexistence relies on competition between individuals of the same species being larger than competition between individuals of different species. Competition between individuals of the same species must be large enough to keep any species from taking over and outcompeting all other species in the community. However, more recent work has highlighted the role of natural pathogens. Stable coexistence of many species may be favored if individuals of one species cannot live in close proximity to each other due to disease.

Plant Pathogens and Biodiversity

View looking south from the canopy tower at the Gamboa Rainforest Resort over the confluence of the Panama Canal and the Chagres River near Gamboa, Panama.

For example, picture a crowded forest with many adult trees of the same species releasing wind-dispersed seeds (like the helicoptering seeds of a maple). Very few, if any, of the seeds that fall near to the adult trees will germinate and reach maturity. As you walk away from the clump of adult trees, you will begin to find more germinated seeds that reach maturity (Augspurger 1983). These seeds are farther from tough competitors of the same species (adult trees) and are away from the plant pathogens that may be living in the adult root system. In our hypothetical forest, the plant pathogens that feed on young maples are keeping maple from dominating the forest, allowing other species that aren’t affected by the pathogen to thrive; in this way, plant pathogens play a role in the maintenance of biodiversity.

Drivers of Biodiversity

Our guest this week, Tyler Schappe, studies interactions among plants and fungi in the Neotropical forests of Panama. Tyler is broadly interested in what drives the maintenance and diversity of fungal communities, and how this, in turn, can affect tree communities. Tyler spent the summer of 2015 collecting 75 soil cores from three forest plots in Panama. Using DNA sequencing with universal genetic markers, he was then able to identify the fungi within the soil cores to species and functional group (decomposers, pathogens, plant mutualists, etc.). So far, Tyler has found that tree communities and soil nutrients affect the composition and diversity of fungal guilds differently. As expected, guilds that form mutualistic relationships with trees are more strongly correlated with plant communities. Interestingly, soil properties influence the species composition of all fungal guilds, including plant pathogens, pointing to the mediating role of soils as an abiotic filter. Overall, Tyler’s results, along with other research, show that soil fungal communities are an integral component of the plant-soil relationship since they are driven by, and can affect, both. Together, plants, soil, and fungi form a tightly connected three-way relationship, and wanting to understand one of them means having to study all three together.

Tyler’s work with fungal communities in Panama sheds light on belowground interactions and their implications for plant ecology. His research is one piece of evidence that may help us to understand why there are so many plant species, how they coexist, and why some species are common and some are rare. Are plant pathogens significant contributors to species richness and biodiversity? If so, what modulates plant pathogens, and how can that indirectly affect tree communities? To find out more about Tyler’s work check out these two sources from the Journal of Ecology and Science.

Spend sugar to make sugar

Stand of bur oak trees in a remnant oak savanna at Pheasant Branch Conservancy near Middleton, WI in early winter.

At a young age, Tyler began to realize how connected the world was and how plants and animals function in an ecosystem. The functioning of organisms and of ecosystems came into focus for him while in college at University of Wisconsin-Madison. He took a course in plant ecology from Dr. Tom Givnish who described plants in terms of economic trade-offs. For example, energy invested by plants in vertical growth cannot be invested in defense or reproduction; different allocations of resources can be more or less advantageous in different environments. Tyler decided to pursue graduate school at Oregon State while completing a fellowship with the Smithsonian Tropical Research Institute in Panama, where he met his current advisor, Andy Jones.

Tyler is defending his Master’s thesis August, 29 2017!  We are glad he can make time to talk with us on Inspiration Dissemination this Sunday August, 13 at 7 pm. Not a local listener? Stream the show live!

Beetle-Seq: Inferring the Phylogeny of Clivinini

We humans are far outnumbered by organisms that are much smaller and “less complex” than ourselves. The cartoon above depicts representatives of major groups of organisms, and each organism is drawn such that its size reflects the number of species contained within its group. The bird, the fish, and the trees look as expected, but you may notice the enormous beetle. No, beetles are not generally larger than trees or elephants, but there are more species of beetles than any other group of organisms. Beetles are a wonderful representative of the biodiversity of the earth because they can be found in almost every terrestrial and non-marine aquatic environment!

Examples of carabid beetles of the tribe Clivinini (top row; photos with ‘HG’ – Henri Goulet, otherwise – David Maddison). Male genitalia of a clivinine species, Ardistomis obliquata, with possible ‘copulatory weapons’ (right) and several examples of clivinine female genitalia (bottom row) modified from Zookeys 2012;(210):19-67 shared under CC BY 3.0.

Our guest this week, Antonio Gomez from the Department of Integrative Biology, studies a group of beetles called clivinines (pronounced kliv-i-nīnz) which has 1,200 species, and potentially more that have yet to be discovered. Antonio is also particularly interested in the morphological diversity and evolution of clivinine beetle sperm. Antonio wants to know: What is the evolutionary history of clivinine beetles? What is the pattern of morphological diversity of sperm in clivinine beetles, and how are sperm traits evolving? The objective is to collect beetles, study their form, sequence their DNA, and understand their diversification.

Several examples of sperm conjugates (cases where two or more sperm are physically joined and travel together) in carabid beetles. Conjugation is considered rare, but in carabid beetles, it’s the rule and not the exception to it. In many carabids, sperm leave the testis but do not individualize. Instead, they remain together and swim as a team.

This is no small task, but Antonio is well equipped with microscopes to dissect and describe beetle anatomy, a brain geared to pattern recognition, and some fresh tools for genome sequencing. All of this is used to build an evolutionary tree for beetles. This is kind of like a family tree, but with species instead of siblings or cousins. Antonio and other students in the lab of David Maddison are adding knowledge to the vastness of the beetle unknown, bit by bit, antenna by antenna, gene by gene.

Antonio Gomez collecting beetles near a really bright light (a mercury vapor light trap) near Patagonia, Arizona.

Like many of our graduate students at Oregon State, a group of great mentors can make all the difference. Before working with Dr. Kelly Miller at University of New Mexico, he never knew beetle phylogenetics meant exploring exotic locations around the world to collect and potentially discover new species. As an undergraduate, Antonio even named a species of water beetle, Prionohydrus marc, after the undergraduate research program that go him started as a beetle systematist, the Minority Access to Research Careers (MARC) program. Pretty amazing. That was not his first or last research project with insects before he joined ranks at Oregon State, he also was participated in a Research Experience for Undergraduate program at the California Academy of Sciences and completed a Master’s at University of Arizona. Now he has ample experience working with beetles and is maybe a little overwhelmed but still excited by the unknown beetle tree of life. Next on his list of questions: did the ancestor of all clivinines likely have sperm conjugation?

You’ll have to tune in on Sunday April, 16 at 7 pm to hear more about that evolutionary arms race!
Not in Corvallis? No sweat! Stream the show live.

Can’t get enough? Follow this link to learn about Stygoprous oregonensis, a blind subterranean diving beetle that had not been seen in 30 years. Recently, a team of researchers that included Antonio Gomez reported the discovery of more specimens, which allowed them to place Stygoporus in an evolutionary tree.

Go With The Flow

If you get the chance to meet Emily Khazan, you’ll probably learn a thing or two about damselflies. You can think of them as smaller versions of dragonflies whose wings can fold back

Emily attempting to collect ants off of baited trees in Costa Rica

Emily attempting to collect ants off of baited trees in Costa Rica

when they perch. They need bodies of water to breed and live, and sometimes, water caught in the leaves of a plant is all that’s needed for survival. For her Masters degree, she worked with damselflies that lived in old growth forests in Costa Rica. She would wade through thick underbrush, collecting data, trying to understand how damselflies were affected by a highly impacted landscape throughout a biological corridor that was designed for restoration of habitat for a large-bodied, strong-flying bird.

 

These days, you’ll find her stooped over the bank of a river in the desert, collecting the various insect inhabitants that live there. Working in the David Lytle lab, she wants to understand how these aquatic invertebrate communities are affected by climate change by seeing how they respond to the changing river flow. Why does it matter? Because aquatic invertebrates not only serve as a food source for fish, and a good indicator for water quality, but because our world is interconnected, biodiversity matters.

 

One of Emily's current study sites: the lower Salt river outside of Phoenix, AZ

One of Emily’s current study sites: the lower Salt river outside of Phoenix, AZ

So, how does one go from research in the tropics to the arid lands of the American southwest? For Emily, its a story where she continuously reinvents herself as she moves across the landscape. This Sunday, you can hear her journey from her first ecology course at the University of Michigan, to persevering through an underfunded Masters degree fueled by her weird love of damselflies and their environment, to leading a research station in Costa Rica, and finally coming to OSU to study aquatic invertebrates.

Tune in Sunday, June 12, 2016 at 7PM PST on KBVR 88.7FM or stream live at http://kbvr.com/listen

View of the Costa Rican coast line from the Caño Palma Biological Station (http://www.coterc.org/)