November 26, 2012

Leave it to Beavers

I've found that usually when we go out exploring, no matter how much we've tried to find out about our destination beforehand, there is usually at least one surprise in store for us. Here is the unexpected sight that we came upon recently at Kiser Lake Wetlands State Nature Preserve:

Of course I had to get a closer look!

Clearly, this was the work of a North American Beaver (Castor canadensis), and it looked like that work was quite recent. I have seen lots of beaver evidence in my years of hiking and working outdoors, but never have I seen a freshly-gnawed half-felled tree, looking as precarious as this one was! I was tempted to see what would happen if I pushed it, but I resisted.

These large semi-aquatic nocturnal rodents eat tree bark and the cambium layer just under the bark. Obviously, this individual stripped the tree all the way down to the structural wood, as far up as it could reach, and then starting to gnaw into the wood to take down the tree. They also eat a variety of aquatic vegetation.

An even closer look reveals the beaver's tooth marks:

Work like this is likely to wear down the strongest of teeth; fortunately the beaver's strong incisors continue to grow throughout its life.

This seemed like a pretty big tree for a beaver to deal with, especially since the nearby stream was small and not flowing very rapidly. I didn't see any evidence of beaver dams nearby so I don't know what this tree's destination might be.

Beavers were extirpated in Ohio by 1830 after trapping by both Native Americans and settlers who sold the pelts for use in tall beaver felt hats, which were all the rage in England. The heaviest trapping occurred between 1750 and 1800. 

About 100 years later, beavers were again active in Ohio. Now, although seldom seen, they are quite common and often wreak havoc with culverts and flood control facilities. Their dam building also increases wildlife diversity and continuously changes the landscape in natural areas.

Since I've gotten kind of interested in Pleistocene mammals since I started doing this blog it is interesting to note that the North American Beaver that we are familiar with is not the first beaver species known to live in Ohio. That honor would have to go to the Giant Beaver (Castoroides ohioensis), which became extinct only 10,000 years ago. This animal was 7 1/2 feet long and weighed 400 pounds! In Ohio it ranged from the western border east to the Columbus area. What a different place this must have been!

For more beaver information and a cool video, check Jim McCormac's recent post over at Ohio Birds and Biodiversity.

Kaiser Lake Wetlands State Nature Preserve is well worth a visit with its boardwalk that allows access to an alkaline fen and marsh, rare habitats in this area. Here is a picture of Stiff Gentian (Gentiana quinquefolia), a lovely late-fall wildflower that often blooms into November:

November 18, 2012

A Bittersweet Tale

Even after most of the leaves have fallen from the trees, late fall has a lot to offer in the way of color and interest. Recently we noticed these bright berries on a walk in a nearby park:

I recognized them as the fruit of a woody vine called bittersweet, which is often used in fall wreaths and other decorations. I hope that this particular plant is American Bittersweet, Celastrus scandens, but I suspect that this plant is its extremely nasty cousin called Oriental Bittersweet, C. orbiculatis. Without leaves they are hard to tell apart on a small plant, but the oriental variety tends to have fruit all along the twigs rather than just at the tips. 

What's so nasty about Oriental Bittersweet? It is one of North American's most invasive plants. Its seeds are readily spread by birds, and their germination rate is very high. The plant grows rapidly and can engulf large trees, out-competing them for sunlight. The really menacing thing about these vines is that they can grow up to 4 inches in diameter and can literally strangle a large tree by compressing its vascular system and preventing the flow of water and nutrients, much like the tropical strangler figs. Here is a picture of the plant that we saw, showing a small woody vine climbing in a twisting fashion up a shrub:

Imagine a 4 inch vine doing the same to a large tree! 

A few days later we were taking a walk in another park and spotted something I'd never seen before: a small tree with what looked like bright pink berries:

I knew it wasn't familiar so I had to take a closer look:

Getting even closer, I saw that the fruit was actually red with a pink covering, and it certainly had a structure similar to the bittersweet we had seen a couple of days before:

A bit of googling and checking in some books soon revealed the plant to be a small tree or shrub called American Wahoo (Euonymus atropurpureus). It too has an invasive cousin, E. alatus, which is the common landscape plant known as burningbush

According to Horticulture Magazine, American Wahoo is an excellent choice to replace E. alatus in the home landscape. "Once the foliage drops, the red fruits inside light pink capsules will stop traffic." It certainly stopped me! It is native to the eastern half of North America, and is generally found along streambanks but can do well elsewhere also. American Indians believed it to have a "warrior spirit" and planted it around their camps to keep enemies out.

So back to the fact that both bittersweet and American Wahoo have bright fruits which are revealed with the opening of a colorful capsule. Well, a bit more research reveals that both plants are members of the botanical family called Celastraceae, or the bittersweet family. Most of the genera within this family are tropical, with Euonymus, Celastrus, and one other being the only ones to grow in temperate areas.

Both American Bittersweet and American Wahoo are interesting plants to find when hiking in late fall. Both can be fun additions to the home landscape as well. Just be sure to avoid the nasty relatives! (Always good advice as Thanksgiving approaches...)

November 11, 2012

Big Darby Headwaters Nature Preserve

I have probably spent literally hundreds of hours with students of all ages in Big Darby Creek, studying stream ecology and just plain having fun. Oh—and I’ve had some wonderful kayaking and canoeing adventures too.

Big Darby Creek in central Ohio has been designated as both a State and National Scenic River, because of the diversity of plants and animals that live on, in, under and around it. The raccoons in the photo below (you might have to squint to see them) may not know it, but the creek also is one of The Nature Conservancy’s Last Great Places, so designated because healthy streams of this type, that originate as cold water seeps, are very rare in North America.

Big Darby, and its main tributary Little Darby Creek, run for 82 miles through several Ohio counties and drain a watershed of over 500 square miles. For much of their distance the creeks are lined with mature forests which keep agricultural and other pollutants out of the stream and feed the system with the leaves that drop each fall. 

Development pressure, farming, bridge and highway construction, and other disturbances have, however, threatened portions of the stream and require continuous monitoring.

The creeks support nearly 100 different species of fish, some endangered, and 44 species of mussels, which is truly remarkable. Some of my favorite Darby Creek experiences involved noodling around for different kinds of mussels, and one awesome day watching representatives of the Ohio Environmental Protection Agency employ a method of stunning fish to examine their condition and to inventory species.

But recently I had a different Darby Creek experience when we visited the new Big Darby Headwaters Nature Preserve just northwest of Marysville. This land not only preserves upper reaches of the creek's watershed, but it is also the site of an extensive stream restoration project. A segment of the stream that had been turned into a man-made channel along a highway has been transformed into a much more natural meandering configuration by a project sponsored by The Nature Conservancy. This new stream mimics the natural flow of the stream from its beginnings as a series of seeps and wetlands, and already has resulted in increased wildlife diversity in the area.

For the whole story, try to plan a visit to this preserve. Excellent interpretive signs introduce the creek and the restoration project. The 2.5 mile (round trip) trail is a wonderful hike of minimal difficulty through forests and abandoned farm fields which, when we visited, were lovely with goldenrod and purple New England Aster. 

This project will go a long way toward ensuring that the Darby continues to support diverse plant and animal populations and that it continues to provide excellent educational and recreation opportunities. I can't wait to get back into the creek!

November 4, 2012

Botanical Hitchhikers

Those of us who grew up roaming woods and meadows can remember often coming home with a variety of hitchhiking seeds attached to our clothing:

Kids that I hung around with called all of them "burs" but we had no idea what the parent plants looked like, since we didn't realize that they had hooked on to us till we were far away and had started picking them off, preferably before going into the house. 

That, of course, served the plants' interests extremely well, since our actions helped to spread their range, avoiding competition with the parent and other plants in their immediate area.

Recently I've started to learn to identify more plants and in the process have found out, in some cases for the first time, where some of these "burs" come from.

At the top of the sock are the hooked burdock burs which are supposedly the inspiration for Velcro®. Each bur contains the small seeds shown in the lower right: 

There are several species of burdock, all native to the old world and widely distributed. The plant's enormous leaves make it nearly unmistakable:

Here is a picture of burdock in bloom:

Next are some of the most common burs, from a plant called agrimony (accent on the second syllable) or groovebur. 

There are 7 species of agrimony that are native to North America and the plant is reported to have a variety of medicinal uses. A member of the rose family, it has small yellow flowers and compound leaves. Here is a picture of the plant showing the flower stalk bearing the burs after blooming:

Here is a close-up view, and notice how the burs are angled down, the better to snag on a passing mammal: 

Next is cocklebur, a member of the aster family.

It is found mostly along streams and in wet areas. Each football-shaped cocklebur fruit contains two seeds. 

It has large coarse leaves like burdock, but in general the plant is much smaller.

Last but not least are the seeds of beggarticks or sticktights.

These come from plants in the genus Bidens and have a wide variety of common names. There are about 200 species of Bidens, and they occur all over the world. Some common members of the genus are not at all showy, with no petals or ray flowers:

Another one in this area is the very showy Nodding Bur Marigold, generally a plant of wet areas:

If you have ever had to cut any of these burs out of your dog's hair or tried to pick one out of your carpet you can really appreciate their tenacity. Plants whose seeds stick to clothing, fur or feathers are termed zoochorous and they have managed to exploit this characteristic to spread all over the world. 

A few posts back I wrote about the huge Pleistocene mammals that roamed Ohio just 13,000 years ago, and postulated that they probably had lice and fleas. Just think about what else they were carrying around in all that fur!