Science Workshop: Species Invasions, Niche Relationships, and Species’ Responses to Climate Change

Dov Sax

Dov Sax

Science/Math workshop this week features Dr. Dov Sax of Brown University’s Department of Ecology and Evolutionary Biology.  He will speak at 1:00 pm, Friday 20 March, in Dickinson 232.


Eucalyptus species, native to Australia, have become highly invasive in several other parts of the world — here in the hyperdiverse native shrublands of Cape Province, South Africa (photo, Kerry Woods)

Dr. Sax’s research explores the dynamics of biodiversity at very large scales in time and space.   You can find information about his research, along with links to a long list of heavily cited publications, at his website.  While his publications address topics from the spread of disease to evolution on islands to the implications of climate change for conservation policy, his talk this Friday will focus on the core of his research program — a set of interlocking questions about species invasion and the interactions between species’ ranges and changing environments.

If you’d like to prepare some insightful questions for his seminar, I’d suggest reading some of his recent papers.  Good examples would be Early and Sax (2014) and Fridley and Sax (2014) (with Bennington alum, Jason Fridley).





The Dinaric Alps, looking south from Slovenia into Croatia


Ljubljana street scene

What did I manage to accomplish in the seven months since spring term 2014 — my just-completed sabbatical?  Maybe talking about it will help me sort it out…  Some field work and new analyses, approaches, and results from long-term studies in Michigan old-growth forests (we’re still trying to figure out what’s going on in these systems).  Networking with forest ecologists in Europe during a Fulbright project in Slovenia and through a new consortium based in Belgium.  Plans and proposals for new projects.  There’ll be some new research results and data-graphics.  There’ll also be a little bit of travelogue; Slovenia is a tiny country with some of the most distinctive landscapes and forests in Europe (and one of its most under-rated cities).  Maybe some stories about cuisine — Slovenian (przut, pork fat, bear sausage, strange wines), Belgian (beer, chocolate, mussels), Michigander (pasties).  Students in the field in Michigan, enjoying mosquitoes.

FWT — Naima and Roi in Sri Lanka

(from Naima Starkloff and Roi Ankori-Karlinsky)

Naima measuring tree diameter

We spent FWT in the hills of Sri Lanka investigating the conservation potential of Home Gardens. This agroforestry method, used in Sri Lanka for several thousand years (yep, several thousand) mimics the structure and composition of natural forest but combines it with crops, fruit trees, etc. It’s managed by human beings, from the species selected to desired growth rates. Naima’s research (for her senior thesis, with Kerry Woods) looked at bird diversity within these forests in comparison with eucalyptus plantations (another human-managed habitat) and a preserved natural habitat. Roi did a more focused study on one bird species, the endemic and endangered Sri Lanka Wood Pigeon.

We got up with the sun and counted birds for an hour each morning. We spent the afternoons measuring trees, assessing canopy structure, and fending off cobwebs. We both had to memorize and recognize 82 different bird calls.  We ate lots of curry, hiked through some of the most beautiful tropical forests Roi had ever seen (ok, he’s never been to the tropics before), and did a lot of data entry in the mosquito-heavy evenings.

Naima’s project explores the potential for using bird diversity as an assay to measure conservation potential in human forests such as home gardens and Eucalyptus-Pine plantations, as well as in native-mixed deciduous forests. More specifically, she is testing the hypothesis that habitat/canopy complexity is a driver of avian diversity across these habitats.  Spring semester will involve analyzing these data for her senior thesis; look for it in the library, as well as in a Science Workshop presentation in May! You can read more about Naima’s work now on her tumblr.

Roi on a hot tea break in a foggy Eucalyptus-pine forest

Under the tutelage of Nireka Weeratunge, Roi played “catch the pigeon” in the afternoons. Normally a forest bird, the Sri Lanka Wood Pigeon also enjoys anthropogenic goods. It loves the home-garden’s buffet of tea trees, cinnamon leaves, fresh pepper, and the canopy cover provided by the mango trees.  Roi confirmed two nesting pairs and suspected a third, and found a nest with an egg on top of a mango tree.  Though rare and fragile, the Wood Pigeon seems to like the home-garden atmosphere, suggesting  a potential role for home-gardens in protecting this Sri Lankan endemic species. Look out for a presentation by Roi on his FWT in the first couple weeks of term!


Alum research in the NY Times



invasive Eurasian barberry (Berberis) in Acadia National Park (photo, Kerry Woods)

Research of alum Jason Fridley (’97, Ph.D. Univ. North Carolina), now a professor at Syracuse University, is featured in Carl Zimmer’s science column in the New York Times:

Several of Jason’s research projects have received wide recognition.  Zimmer’s column focuses on his work on the ecology of invasive species and its evolutionary underpinnings.  Fridley has worked with Dr. Dov Sax of Brown University to explore whether a Darwinian perspective on ecological relationships can help understand patterns of invasion.

Old-Growth Forests in Slovenia


A foggy view of an old-growth forest dominated by European beech and white fir (the rock is limestone; this forest reserve is on ‘karst’ topography with many large sinkholes).

Faculty member Kerry Woods is spending a month in Slovenia as a Fulbright ‘senior specialist,’ where he is collaborating with colleagues at the Forestry School of the University of Ljubljana to build a network of researchers working with long-term permanent plots to understand ecosystem properties of old-growth forests.  Such forests are interesting, in part, for their rarity.  Europe retains very few old-growth forests, but the small country of Slovenia (one of the most heavily forested countries in Europe) has quite a few tracts, and several host study plots established over 30 years ago.

Such under-used, heritage data-sets can give us insight into the ‘baseline’ properties of forest ecosystems.  Does diversity increase or decrease with forest age?  Old forests can be very large carbon reservoirs on a per-area basis, but are they acting as carbon sources or sinks?  Do such properties and processes converge among old-growth temperate forests in different parts of the  world (for example, the old-growth forests Woods studies in Michigan)?

The project will culminate with a workshop attended by researchers from several European countries.  The workshop will, we hope, lead to future collaborations undertaking integrative meta-analysis of data-sets from temperate forests around the world


; they can help us understand the processes that maintain diversity,

Old-growth Fieldwork


Part of the study area at the Dukes Natural Area in the Hiawatha National Forest

Two 2014 grads — Joe Kendrick and Ellen Hanson — and two current students — Charlotte Uden and Roi Karlinsky — are spending four weeks in Michigan’s Upper Peninsula working with faculty member Kerry Woods in his on-going research on old-growth forests.  They join about 40 other student researchers who have worked on this project since 1989.


It’s good to find a log for lunch; the mosquitoes are worse near the ground. (Roi Karlinsky, Joseph Kendrick, Ellen Hanson, Charlotte Uden)

The project revolves around monitoring of permanent study plots established as early as 1935 — one of the longest-term records for any old-growth forest.  The work has been supported by the National Science Foundation, the Mellon Foundation, the U.S. Forest Service, The Huron Mt. Wildlife Foundation, and Bennington College faculty grants. A series of resulting publications can be downloaded from this site.

The 2014 season features a late season — trees are still leafing out along the Lake Superior shoreline, where ice-floes were still present three weeks ago — and unusually numerous and hungry mosquitoes.  A large supply of deet (N,N-diethyl-meta-toluamide) is proving essential.

This is our lab: carbon budgets in campus forests

The “Forests” class — a field-oriented class introducting concepts of ecology and evolution (taught by faculty member Kerry Woods) — recently remeasured two study plots established in 2004 in campus forests.

Processed with VSCOcam with m5 preset

Class members posing with their trees. Left to right: Emily Sanders, Dane Whitman, Nick Atherton, Kevser Kedici, Syvlia Madaras, Kily Dalrymple. Photo by Reily Gordon.

Remeasurements will allow estimation of biomass accumulation and turn-over — in other words, whether these forests are overall carbon sinks or sources. (the stand pictured here is a plantation of native red pine planted in the 1960s by former faculty member Bob Woodworth and his students).

It’s generally thought that New England’s forests are ‘carbon sinks’ because they are relatively young, post-agricultural ecosystems and so still growing — but we do not know how generally or how long that can be expected to be true, so we will keep monitoring the roughly 200 acres of forest on the Bennington College campus.

Faculty Research on ecological effects of changing climates


Old-growth forest at the Dukes Research Natural Area (U.S. Forest Service) in northern Michigan — source of the data-set used in published analyses.

Faculty member Kerry Woods participated in a multi-author study assessing the effects of climate change on forest understory communities in North America and Europe.  Using multi-decade data-sets from 29 research sites analyses show that a general trend of compositional change reflecting increases in warm-adapted species may be moderated where forest canopies have become denser. This work was published online (before print) in the Proceedings of the National Academy of Science  in a paper titled “Microclimate moderates plant responses to macroclimate warming” (doi: 10.1073/pnas.1311190110).  Woods contributed one of five data-sets from North America; his long-term studies in old-growth forests of northern Michigan have supported several other publications.  Another of the North American data-sets is from Peter White of the University of North Carolina — a Bennington alum from 1971.

This research has been reported by the BBC, on Belgian national news (including a video clip of lead author Pieter de Frenne of University of Ghent — in Dutch), and in press releases from Oxford University and several other universities.

This is our laboratory: Ecology classes study the local landscape

IMG_9975Each year, the introductory ecology and evolution class participates in a multi-year study assessing how the history of agricultural usage and abandonment has affected ecosystem patterns over our local lanscape –  once almost entirely cleared and now over 80% forested. In addition to conducting quantitative vegetation sampling, we ‘read’ stories told by stone walls, soil properties, and remnant trees like this white oak, whose growth form indicates that it was well-established when this site was still an open pasture.

Class excursions also explore the rich diversity of habitats and communities found within a short van-trip from the College, including sub-alpine forests near the summits of surrounding mountain ranges (here, Mt. Greylock in the Taconic Mts., the highest point in

Ecology class in the lab - at the summit of Mt. Greylock

Ecology class in the lab – at the summit of Mt. Greylock



Alum news: Conservation education at Disney World

Emily Disney 2

Emily Mikucki on the job as a conservation educator at Disney World

Since graduating last spring, Emily Mikucki has been working as a conservation educator at the ‘Animal Kingdom’ park at Disney World.  She reports that she gets to “interact with guests through the Wilderness Explorers Program [to] help them learn about wildlife, animal behaviors and conservation.”  Emily’s work at Bennington focused, from the beginning, on the ecology and conservation of her favorite group of organisms — insects and, more specifically, butterflies and moths (the Order Lepidoptera).  Not surprisingly, she reports that her favorite part of the work at Disney World “is informing guests (primarily kids and families) about the different insects we have, and their morphologies and behaviors, and helping to build young biologists and entomologists.”  She also studied Spanish at Bennington, and spent several summers and FWTs doing conservation work in natural areas and conservation programs in Latin America.  This has also helped her in her job at Disney World, where she is part of the language program (“it’s says español on my name tag”).