Terrestrial ecosystems

Elizabeth Osborne

4 May 2013

8 AM

Coverdale Farm Preserve

Hockessin, DE

On May 4, 2013, the Naturalist Certification Class took a walk around Coverdale Farm Preserve to observe different habitats, measure their health, and learn more about the three basic roles an organism may fulfill in an ecological web.

In the lecture preceding the class, we learned that living things may be producers, consumers, or decomposers.

Producers get energy from non-living things like soil, sun, and air; they make their own food. 

Consumers get energy from other living organisms.

Some are herbivores (they eat only plants),
some are omnivores (they eat plants and animals),
and some are carnivores (they eat only animals).

Decomposers break down dead things and return energy to the ecological system.

In addition, we talked about forest stratification. The forest may be divided into four basic layers: canopy (the crowns of trees), understory (the lower level of trees), the shrub layer (five to fifteen feet up), and the herb layer (ferns, flowers, and grasses on the forest floor). Things like elevation and proximity to water may cause one or another layer to be especially abundant or very sparse.

Finally, we discussed indicator species. These are plants or animals that require a healthy habitat to grow. If some or many of an indicator species is found in one area, that habitat may be ecologically diverse and stable. For example, the larva of the stonefly are only found in very clean streams, so their presence is a good sign of the stream's health.

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Before we set out, we got to see some Eastern bluebird (Siala sialis) babies from a box built by Ian, a member of the class. He is working on a project to measure the stress hormones of parent birds.

Baby bluebirds

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The first ecosystem we visited was a thicket, a mesic  habitat (meaning it has a balanced moisture supply. There are two other kinds of habitat: xeric (very dry, like a desert), and hydric (very wet, like a swamp).

Thickets provide food, protection, and shade to wildlife. A good description of their value can be found here: http://www.tnwildlifehabitat.org/manage.cfm?uid=11071409080729257&category=habitat

The Coverdale meadow, once cleared for agricultural purposes, is now being converted to prairie. Native warm season grasses were just starting to grow at the time of this walk.

 

In our thicket, we observed several invasive species: Autumn Olive (Eleagnus umbellata), Multiflora Rose (rosa multiflora), Oriental Bittersweet (Celastrus orbiculatus), and Japanese Honeysuckle (Lonicera japonica). These plants were imported because they could survive well under harsh conditions. Unfortunately, this same hardiness is harmful to native species; invasive plants are able to multiply more quickly than natives, and they monopolize nutrients and sunlight, throwing their adopted ecosystem out of balance. Autumn olive, for example, is able to fix nitrogen, like bean plants do, and so make use of soils too poor for other plants.

Some good may come of invasive species. The hips of the muliflora rose can be used to make tea; they are also food for lots of different animals: http://mag.audubon.org/articles/blog/praise-multiflora-rose 
Although autumn olive takes over forest and hedge areas (parts of Lums Pond state park are a solid wall of autumn olive) and is being eradicated, its berry is edible (and healthy, according to http://foragersharvest.com/autumnberry-autumn-olive/)

More information on invasive species can be found at the National Invasive Species Information Center: http://www.invasivespeciesinfo.gov/index.shtml

Japanese Honeysuckle

Autumn Olive leaves have a silvery underside, and the branches are speckled.


What the autumn olive berry looks like in the fall

Oriental bittersweet berries in the fall

Multiflora Rose has thorns, and the base of the leaf stem is fringed.

Because Coverdale Farm is a managed habitat, several native plants were also doing well. These included Sassafras (Sassafras albidum) and Eastern Red Cedar (Juniperus virginiana). 

 Joe had an app on his tablet that played bird songs to attract males from nearby trees. The first bird we called was a White-eyed Vireo (Vireo griseus). Although it had been singing nearby, it did not come for the call.

A Common Yellowthroat (Geothlypas trichas), however, was interested enough to come nearer. This is an indicator species--it needs dense vegetation to thrive.




The Common Yellowthroat is sitting in this tree, although it's difficult to tell from the picture.

An Eastern Towhee (Pipilo erythrophthalmus) also responded to the call. 

Continuing along the thicket, we saw crabapple trees in flower. These are a non-native species, but are not invasive.

Flowering crabapple tree

Invasive Garlic mustard (Alliara petiolata) was growing at the edge of the thicket.  According to http://www.nps.gov/plants/alien/fact/alpe1.htm, garlic mustard is not easily dispersed by wind or water; people or animals track it into new areas. It is actually able to change the pH of its surrounding soil so that other plants can't grow there.

Garlic mustard in Price Park, Greensboro, North Carolina, 5 August 2013

We also saw Poison Ivy (Toxicodendron radicans). Although the oil from poison ivy is highly irritating to people, the berries are an important food source for birds in winter. 

This sign at Lums Pond State Park shows poison ivy as it looks in both summer and winter.

In the thicket were blackberry bushes (flowering plants in the genus Rubus and family Rosaceae). They can be distinguished from raspberry brambles because they have grooved stems; raspberry bush twigs are rounded. According to wikipedia, another main difference between raspberries and blackberries is that the receptacle stays on the bush when a raspberry is picked, leaving the core of the raspberry hollow, while the blackberry takes the receptacle with it and so has a filled center.

The Wikipedia article also says the following:

The genus Rubus is a very complex one, particularly the blackberry/dewberry subgenus (Rubus), with polyploidy, hybridization, and facultative apomixis apparently all frequently occurring, making species classification of the great variation in the subgenus one of the grand challenges of systematic botany.

We saw a flowering dogwood (Cornus florida). The white "petals" on the dogwood are actually bracts (specialized leaves), just as on a poinsettia.

Lamb's ear (Stachys byzantina), native to Turkey and Armenia, was growing in the thicket.

Field sparrows (Spizella pusilla) nest in the thicket. The call of the male sounds like a pong pong ball being dropped. 

 

We heard the call of a Prairie Warbler (Setophaga discolor) , an indicator species of extensive thickets.

 

From the meadow, we walked into an early successional forest. After a disturbance, like  a fire or the conversion of forest to farmland, habitat in a temperate climate like ours goes through different stages (or successions): from meadow to shrubland/thicket, from thicket to early successional forest, and from this early forest to mature forest.

 

 

Plants found as we walked the path within the woods included the following:

 Bulbous buttercup (Ranunculus bulbosus),

Bulbous buttercup

Bush honeysuckle (Diervilla lonicera), Lady's Thumb (Persicaria maculosa--so called because it is supposed to have the thumbprint of the Virgin Mary on the leaves--not native) It has a red sheath around its stem:

Lady's Thumb

Common blue violet (viola sororia):

Common Blue Violet

We heard bluejays (Cyanocitta cristata) scolding in the trees.

Goldenrod (plants in the family solidago) had spidery veins.

Bedstraw, in the galium family, was once used to make mattresses. Names for Galium aparine include Goosegrass, Cleavers, Clivers, Stickywilly, Stickyweed, Catchweed, Coachweed, Common Bedstraw, and Robin-Run-the-Hedge.

Bedstraw

Bedstraw

 

Christmas fern (polystichum arostichoides) gets its name because it is an evergreen fern and is green even in the winter.

 

A baby sugar maple (acer saccharum) tree was growing along the edge of the thicket.

Cinquefoil (potentilla recta):

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The next ecosystem was Northern riverine forest. The soil was darker than the soil we had examined earlier because not as much air was in it. Mesic soil, on the other hand, is well-drained. Air in the soil causes metal to rust, giving mesic soil a reddish color. 

This area had an open canopy, a medium-thick understory, thick shrubbery and a thick grass layer.

Riverine soil

Some plants we found in the riverine forest:

springcress (cardamine bulbosa)

 a common plant with heart-shaped leaves (still working on identifying this one):

a native mustard with four petals on the flower:

 skunk cabbage (symplocarpus foetidus), an indicator of wet soil.

We also saw spring beauty (claytonia virginica).

The trees in this area included the Green Ash (fraxinus pennsylvanica) and the Black Walnut (Juglans nigra), which feeds many animals. 

A Baltimore oriole (icterus galbula) likes big trees.

A yellow warbler (dendroica petechia), is a neotropical migrant

American sycamore (Plantanus occidentalis)

An ash-leaf maple (acer negundo) has leaves growing opposite one another. This tree is the most widespread in North America.

Here is Joe holding up a horsetail fern (equisetum).

Invasive lesser celandine (ranunculus ficaria)

A green heron (butorides virescens) flew into a tree a few hundred feet away. This is one of the only solitary herons. 

The soil we saw here was, for some reason, darker above than below. 

A slippery elm (ulmus rubra) had a vaselike shape. 

Further on, the canopy was thick, the understory was thick, the shrub layer was more open, and the lower layer was almost bare. 

 

We heard a baby Eastern towhee who didn't quite have his song down. 

Joe took the diameter of a beech tree-- 31 inches. Multiplying this by the age factor of the beech tree gave it an age of 181 years. Beech trees only sprout in shady forests. At the time the other trees in the forest were cut down for their wood, the wood and bark of the beech were not useful, so it was left behind. It sprouted in 1832.

A flowering tree-- a pinxter azalea (rhododendron canescens)-- was the mystery plant I drew, although I also liked a shelf fungus (fungi in the phylum Basidiomycota). The shelves are called conks. 

Lion's paw (leonois leonura)

Big, straight tulip tree (liriodendron tulipfera). Its age factor is 3. The leaf looks like the face of Sylvester the Cat.

A white oak had rounded lobes on the leaves.

New York fern (thelypteris novaboracensis) tapers at the top and bottom.

Bloodroot (sanguinaria canadensis)

Ironwood (carpinus caroliniana), also called American hornbeam sapling

Mayapple (podophyllum peltatum) are eaten by turtles.

Solomon's Seal (a flowering plant in the genus Polygonatum)

Joe explained the difference between white oak trees (Quercus alba) and red oak trees (Quercus rubra). The white oak has round lobed leaves. Its acorns rot fast. The red oak has bitter acorns that don't get eaten immediately by squirrels, as well as bristletip leaves.

A maple leaf viburnum (viburnum acerifolium) has leaves that look like a maple's. Deer love eating these. These are an indicator of a rich, old, healthy forest. 

We also saw false hellebore (veratrum viride) and dentatum viburnum, also called southern arrowwood.

We saw some lichens on a rock. There are three kinds of lichens--crustos, folios, and fruiticos. This was the crustos. Nobody eats lichens. Not sure where they fit in the ecosystem. 

Painted turtle (Chrysemys picta) was in the pond. 

Bluebells (flowering plants in the genus hyacinthoides)

Trillium is a genus of flowering perennials. 

Invasive burdock (plants in he genus arctium) 

A big bullfrog tadpole was in the pond. They stay tadpoles for up to two years. 

Jack in the Pulpit (Arisaema triphyllum) 

Mountain rhododendron 

Narcissus (plants related to daffodils). 

Japanese barberry (berberis thunbergii) has round leaves. This is an invasive plant. 

We saw a bright red burning bush (Euonymus alatus), another non-native.  

Sensitive fern (onoclea sensibilis) 

A red-leafed maple had three points on each leaf. The stem on the leaf gets red. It is found all over the world.

Another person in the class found a morel mushroom (morchella esculenta).

A showy orchis (galeatus spectabilis) had a white and purple bloom.

A rattlesnake fern (botrypus virginianus) The part that sticks up looks like a rattlesnake's tail--this is the part that makes the spores. 

Spicebush (lindera benzoin) is a plant that deer don't like. In winter, it makes big purple fruits that birds eat. 

We saw a tree covered in mycelia--a fungus that was eating it. 

Also a blackhaw (viburnum prunifolium)

Interrupted fern (osmunda claytoniana)

Royal fern (osmunda regalis)

The root of the spring beauty has as much nutrition as a potato. 

Japanese stiltgrass (microstegium vimineum) is an invasive grass was once used as packing material. 

We saw a native sedge with a triangular stem. Unlike grasses, sedges have edges. 

The last plant we saw was a wild yam (dioscorea villosa).

Species Lists:

Plants:

wild yam

native sedge

Japanese stiltgrass

Royal fern

Interrupted fern

blackhaw

spicebush

rattlesnake fern

showy orchis

sensitive fern

Japanese barberry

Narcissus

Mountain rhododendron

Jack-in-the-pulpit

burdock

bluebells

trillium

false hellebore

southern arrowwood

maple leaf viburnum

Solomon's seal

Mayapple

bloodroot

New York fern

lion's paw

pinxter azalea

lesser celandine

horsetail fern

spring beauty

skunk cabbage

springcress

cinquefoil

christmas fern

bedstraw

goldenrod

blue violet

bush honeysuckle

Lady's thumb

bulbous buttercup

Lamb's ear

Blackberries

Poison ivy

Garlic mustard

Fungi:

morel mushroom

lichens

Trees:

Red-leafed maple

Ironwood

White oak

Tulip tree

beech tree

slippery elm

ash-leaf maple

American sycamore

sugar maple

crabapple

sassafras

Eastern red cedar

Autumn olive

multiflora rose

Oriental bittersweet

Japanese honeysuckle

Amphibians:

Bullfrog

Reptiles:

Painted turtle

Birds:

Eastern towhee

Green heron

yellow warbler

Baltimore oriole

Bluejays

Prairie warbler

field sparrow

Common yellowthroat

white-eyed vireo

Eastern bluebird