Resistance of environmental systems is their capacity to withstand or absorb force or disturbance with minimal change. In many cases we can measure it based on, e.g., strength or absorptive capacity. Resilience is the ability of a system to recover after a disturbance or applied force to (or toward) its pre-disturbance condition—in many cases a function of dynamical stability. In my classes I illustrate the difference by comparing a steel bar and a rubber band. The steel bar has high resistance and low resilience—you have to apply a great deal of force to bend it, but once bent it stays bent. A rubber band has low resistance and high resilience—it is easily broken, but after any application of force short of the breaking point, it snaps back to its original state.



Yesterday I heard a very interesting river restoration workshop at the British Society for Geomorphology meeting. What I’m about to discuss was not the focus of the workshop, but it was triggered by thinking about geomorphology, hydrology, and river science in stream rehabilitation and restoration, which is a big business now.

The stream restoration problem is often portrayed as something like this:


That is, the stream is currently in some kind of degraded, suboptimal, unwanted state. The goal is to restore it to a “natural” or some more desired condition, often conceived as whatever the stream was like before the degradation commenced. There are a number of problems with this, one being that in many cases the pre-existing state is not known. Even if it is, since rivers—like other landforms and ecosystems—are dynamic and changeable, there is no particular scientific reason to believe that, in the absence of human-driven changes, the river would still be now as it was decades ago.



One of my major research interests is the coevolution of soils, landforms, and biota. I’ve been working in this area pretty steadily since about 2000, but until 2013 I was completely unaware of some work being done along the same lines, over about the same time period. This is the work of W.H. Verboom and J.S. Pate from Western Australia, who among other things developed the “phytotarium concept.” Phytotarium defines the specific plants and microbial associates driving specific pedological changes during niche construction. This concept, and a wealth of work on biogenic origins of pedological and geomorphological features such as clay pavements, texture-contrast (duplex, as they call them in Australia) soils, and laterites, was highly relevant to my own thinking (e.g., Phillips, 2009a; 2009b), but though I consider myself familiar with the biogeomorphology and pedogenesis literature, then and now, I had somehow missed it.

Deep sandy duplex (vertical texture contrast) soils, Western Australia. Photo credit: Dept. of Agriculture & Food, Western Australia.

Sycamores and Hillslopes

Below are some recent photographs of sycamore trees (Platanus occidentalis) in limestone bedrock at Herrington Lake, Kentucky (about37.78o N, 84.71o W). As you can see, the tree roots and trunks exploit joints in the rock, and accelerate weathering both by physically displacing limestone slabs and widening joints by root growth, and by facilitating biochemical weathering along both live and dead roots.

Sycamores rock

These are some nice examples of root/bedrock interaction, and the general phenomena are not uncommon, though usually much more difficult to see. The Herrington Lake shores also appear to illustrate a process by which the sycamores accelerate weathering and mass movements (other trees are also involved, but Platanus occidentalis seems to be the most common and effective):

1. Plants colonize the exposed bedrock, with roots exploiting bedrock joints.

2. Tree roots accelerate weathering and loosen joint blocks.

3. While the tree is still alive, root growth envelopes rock fragments and the trees provide a physical barrier to downslope transport.

Biodiversity in the Workplace: Philip Crowley

The College of Arts & Sciences is collaborating on an effort to revitalize science education with the addition of a new science building. Born with ecological ideals in mind, this building will create a learning environment unlike any other on campus as classrooms engage students with the incorporation of nature into the building’s design itself. In this podcast, Philip Crowley, a professor in the Biology Department, describes the new science building from inside and out and discusses what he looks forward to the most.

This podcast was produced by Casey Hibbard

Creative Commons License
Biodiversity in the Workplace: Philip Crowley by UK College of Arts & Sciences is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

For the Birds: Dr. David Westneat Explores What Sparrows Teach Us About Parenting Behavior

David Westneat, professor of biology, has been awarded a grant from the National Science Foundation to study how personality and environment affect the parenting behavior of birds.

Two A&S Faculty Team Up for New Book on Kentucky's Robinson Forest

English professor Erik Reece and Biology professor James Krupa recently released a book that brings to life the history and ecology of one of Kentucky's most important natural landscapes —the Robinson Forest in eastern Kentucky. "The Embattled Wilderness" depicts the fourteen thousand acres of diverse forest region-- a haven of biological richness-- as endangered by the ever-expanding desert created by mountaintop removal mining.

Suburban Ecology and Invasive Species Research Experience at UK

Through a National Science Foundation program called Research Experiences for Undergraduates, 10 students from colleges across the country spent 10 weeks studying suburban ecology and invasive species at or nearby UK's Ecological Research Facility.

This video appears courtesy of Reveal: University of Kentucky Research Media




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