The Grassland Biome(s)

Grasslands, prairies, steppes, plains - all these names describe the biome where grasses rule.  

tallgrass prarie at dawn

Climate:

The climate for   grasslands is basically dry.  Precipitation usually does not exceed 100 cm per year, with a minimum near 20 cm per year.  Also, grasslands tend to be in temperate  to subtropical areas, often with cold winters and hot summers.  As you can see in the diagram below, average annual temperatures range from below 0 degrees C to about 20į C.  The warmer end of this range would probably tend towards tropical savanna.  As moisture levels increase, grasslands usually give way to temperate forests or taiga, depending on the temperature.

One problem with determining the exact climate for this biome is historical.  There is now some evidence (here, here, here, and here) that suggests that some prairie (at least that intermixed with forests in the more humid eastern United States) was artificially maintained by native American tribes using fire as a tool.  By eliminating trees and creating grasslands they increased biological diversity and populations of such game species as bison and deer.  So, to what extent are grassland habitats the results of "natural" processes or of human interference?

 

World Distribution:  

Whatever their origins, grasslands today are found in areas of the world intermediate in precipitation between deserts and forests.  In the northern hemisphere the main grasslands are the prairies of the midwestern United States and Canada; in Eurasia the maker grasslands are the steppes of Russia and the grasslands of the mideast extending from Turkey to India. Grasslands are also found in South America.  Africa certainly has grasslands, but the majority of them are classified instead as savannas (a tropical grassland with interspersed trees) and they are treated with the tropical seasonal forests here.

In the United States, there are two main types of grasslands. The Tallgrass Prairie (below left), requires more moisture than the Shortgrass Prairie (below right). Mixed-type praries occur between these main types. At their wetter extremes praries blend into forests, on the drier end they grade into deserts.

Temperate Grassland Distribution

tallgrass prarie

Tallgrass Prarie, North Dakota

Grassland, North Dakota

Shortgrass Prarie, North Dakota

      

 

Indicator Plant Species:

 

 

 

Grass.  That would seem to be a good indicator "species" for a grassland.  Alas, it's more complicated than that.  The North American Prairies, for instance, were a lot more diverse than just grasses.  First, we should make a distinction between grasses and other grassland plants.  Grasses are monocots, meaning the seed has one cotyledon. Monocots also have parallel venation in the leaves, and grasses have a distinct growth form as compared to most other plants.  In addition, grasses generally have pollen that is spread by the wind, therefore the flowers are not very showy.  Other grassland plants may be monocots or dicots, and many of them do have showy flowers to attract insects and other pollinators.  Also, be aware that there are plants called "grasses" that are not true grasses (just as dragonflies are not true flies).  Finally, there are a number of plants (rushes and sedges come to mind) which look like grasses but which are not.  All of these may be part of the grassland community.

A complete list of prairie species (at least for North America) would include Big Bluestem, Indian Grass, Blazing Stars, Butterflyweed, Coneflowers, Sunflowers and so on.  A pictorial list can be found here, and a discussion of grasslands here.

The grasses Big Bluestem and Indian Grass are extremely important in the tallgrass prarie of the midwestern United States; these are pictured to the right. Big Bluestem has a seed head that looks like a turkey's foot. Sideoats grama, another tallgrass prarie species, is shown below.

sideoats grama

grasses
   

Old Field Habitat, Ohio

Old Field Habitat, Ohio

 Old field habitats in Ohio have been created where the land has been cleared for agriculture or other uses. An old field is a field being left fallow for a year or so, and it is dominated by some cultivar of grass (a cultivar is a domesticated form of a plant, i.e. most of our agricultural crops).  If you look closely you can also see some asters and some Queen Ann's Lace.  Problem is, everything but the asters (and maybe those too) are introduced species.  This isn't a native grassland by any means. Still, anytime a forest is cleared grasses and grassland species are among the first to recolonize the soil and a grassland habitat will persist until succession proceeds to the next stage.  On the other hand, the North Dakota grassland pictured above right is relatively natural (I'm sure there are introduced species somewhere in the photo, however).  This end of the grassland biome in North America is very dry, grading into desert.  It is sometimes called shortgrass prairie to distinguish it from the moister tallgrass prairie further east.  The Ironweed pictured here can be a grassland species, but it tends towards wetter areas in the grassland.

 

Ironweed (Vernonia sp.) with Hedge Bindweed Vine  (Calystegia sepium)

Ironweed (Vernonia sp.) with Hedge Bindweed Vine  (Calystegia sepium)

Ironweed (Vernonia sp.)

Ironweed (Vernonia sp.) 

Ironweed (Vernonia sp.)

Ironweed (Vernonia sp.) 

Joe Pye Weed - Eupatorium purpureum

Joe Pye Weed - Eupatorium purpureum

Hummingbird Clearwing (Hemaris thysbe)  feeding on Thistle

Hummingbird Clearwing (Hemaris thysbe)  feeding on Thistle

Common Teasel: Dipsacus fullonum

Common Teasel: Dipsacus fullonum

 

A few more grassland plants, native and introduced.  Thistles of various sorts (above right) are native to North American grasslands (although some species have been introduced as well).  The seeds are an important resource for many birds, and, as you can see here, among the pollinators visiting the flowers are the day-flying Hummingbird Clearwing (moth).  This species is unusual in its family (Sphingidae) as most of the others are nocturnal (the adult of the tomato hornworm is among those nocturnal species).  The Joe-Pye Weed above is a native grassland plant that, like the ironweed above, favors wetter areas of a grassland.  It has a number of medicinal qualities.  The teasel, left, was introduced from Europe. The stiff head of the plant was used in machines there to card wool.  Teasel is considered an invasive and noxious plant in some states.

Milkweeds and similar plants such as dogbane are important grassland species.  They get their name from the thick latex sap they contain; a broken leave or stem will ooze this white gummy material for some time.  A feeding insect will also tap into this sap; the sap hardens in the air and gums up the insect's mouthparts.  For good measure, the sap also contains a number of bad-tasting and poisonous chemicals.  Only a few insects have managed to deal with this double-threat, but those who have are often found in great abundance on these plants.  In addition, they are often able to isolate the noxious chemicals and incorporate them into their own bodies, making the insects themselves poisonous.  They warn potential predators of their poison with bright colors, usually red.  Among the insects which can feed on milkweed are the Monarch Butterfly, the Milkweed Bug, and the Red Milkweed Beetle.

Dogbane (Apocynum sp.)†

Dogbane (Apocynum sp.) 

Dogbane (Apocynum sp.)†  

Dogbane (Apocynum sp.)  

Red Milkweed Beetle - Tetraopes tetraophthalmus

Red Milkweed Beetle - Tetraopes tetraophthalmus (with honeybee, on milkweed flower)

Queen Ann's Lace (Daucus carota)

Queen Ann's Lace (Daucus carota)

 

Red Milkweed Beetle - Tetraopes tetraophthalmus

Red Milkweed Beetle - Tetraopes tetraophthalmus

Yellow-eyed Grass (Xyris sp.)

Yellow-eyed Grass (Xyris sp.)

Queen Ann's Lace (Daucus carota) is not native to North America.  A member of the parsnip family and a close relative of the cultivated carrot (it is sometimes called wild carrot), it is now found in many grassland communities in North America.  Note the single black flower at the center of the inflorescence. 

Yellow-eyed grass (left) is not a true grass, but one of the species which carries the common name of grass.  The showy flower gives away that it is insect pollinated; this specimen was in a Florida wetland, but other members of the genus are found in grassland communities.

Indicator Animal Species:

Bison (Bison bison) on the range, Theodore Roosevelt National Park, North Dakota

Bison (Bison bison) on the range, 
Theodore Roosevelt National Park, North Dakota

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

In a grassland, the animals - at least the big herbivores - stick out like sore thumbs, so I've got lots of pictures of these, in fact, one for each continent (thanks to zoos).  Many of these large herbivores migrate with the seasons; in the spring, for instance, American Bison used to follow the melting snow north, this meant they were always feeding on the most nutritious young grass. Fences and interstates make this difficult nowadays.  The American Bison is perhaps THE symbol of the North American Prairie; herd numbering in the millions were common.  Przewalski's horse, from the steppes of Asia, was likewise common and reduced to a pitiful herd in captivity.  Thanks to conservation work at The Wilds in Ohio (and other places) they are now being reintroduced to the wild in Mongolia.  The kangaroo is the bipedal marsupial herbivore of Australia.  Really - look at the head - this is a deer that runs on two legs. 

Africa is a hotspot for mammalian herbivore diversity, partially because the grasslands are interspersed with savannas (which themselves are interspersed with trees).  As mentioned above, the savannas will be treated with the tropical deciduous forests, but a few African animals seem more at home in a grassland than a savanna, so they are included here (remember, these divisions are arbitrary).  Horses appear in Africa in the form of striped zebras, another African favorite is the rhinoceros.

Kangaroo

Kangaroo

 

Grant's Zebra (Equus burchelli bohmi) Lowry Park Zoo, Florida

Grant's Zebra (Equus burchelli bohmi) Lowry Park Zoo, Florida

 

 

 

 

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Ecological Notes:

Intense competition is the norm for plants in a grassland, with sunlight, water, nutrients and space all on the list of things for which competition is intense.  Plants may be annuals or perennials; annuals usually produce more, smaller seeds and are quick to colonize disturbed areas.  Perennials may be better competitors in the long run, and may displace annuals where disturbance is infrequent.  

Roots are one of the most critical parts of the plant in a grassland.  The roots do much of the competing for space, nutrients and water, and the roots may hold most of the biomass of the plant.  If a fire burns an area of grassland it is often the roots which survive and quickly send up new shoots to take control of the airspace above. Many grassland plants spread by roots or rhizomes (a root-like stem); this may be the major form of reproduction in some species (as opposed to setting seeds). The roots are also a vital storage place for nutrients, but compared to forest ecosystems more nutrients are retained in the soil in a grassland.  

Large herbivores may shape grasslands in a number of ways.  First, by the act of grazing they remove some plants at the expense of others; in fact grazers often remove the top competitors (either selectively or by random processes); as a result lesser competitors are able to maintain a place in the ecosystem and diversity is maintained.  Herbivores differ in their effects on plants; sheep are notorious for pulling up the whole plant, often killing it, while horses generally bite off the plant at the root line, allowing it to regrow quickly.  Thus, although grazing by horses may be "gentler" on the plants, grazing by sheep opens up ground for new colonizers, and changes the community in a fundamental way. The feces of the large herbivores provides a concentrated supply of nutrients and food and support an insect and invertebrate community of their own.  As the feces are consumed by invertebrates the nutrients are released back into the soil for new plants (often growing from seeds which passed through the gut of the herbivore unscathed) to use.  In addition, grazing and foot traffic by large herbivores may open up small areas of ground for new seedlings, further increasing diversity.  Birds in the grasslands may consume seeds - either directly or from the feces of mammals - and defecate elsewhere, planting the seeds in a new location in a fresh bed of fertilizer.

In many grassland ecosystems, fire undoubtedly plays a major role.  In wetter areas fires (whether man-made or "natural") may prevent a forest community from replacing the grassland as grassland species in general are more fire-adapted than are the trees of the deciduous forest.  In drier areas, trees may not be able to establish themselves, but the fires still play a role in opening up the community to other species and in recycling nutrients to the soil.

 

Threats:

There are two major threats to grasslands - conversion to agriculture (or urban areas) and global warming and its attendant changes in precipitation.  We'll deal with the latter first.

Many grasslands are in habitats which are marginal for plant growth; that is, they are on the verge of being deserts.  If you read the desert section you remember that one of the difficulties is drawing a line between a moist desert and a dry grassland.  If global temperatures rise, it is predicted that some current marginal grasslands will become deserts as rainfall patterns change.  Unfortunately much of this land is currently rich agricultural land in the United States.  

Another threat is the conversion of grasslands to agriculture (or, worse, cities and urban areas).  Many of our grassland areas are relatively flat and the soils (which hold a lot of nutrients) are easily converted to agriculture.  In most cases this means total elimination of native communities and replacing them with cultivars (most often corn (right), soybeans, wheat, or other grains).  The current model of agriculture in many former grasslands is monoculture, where only one crop is grown in a field at a given time.  While this makes sense from an industrial farming point of view (it is easy to deal with one crop at a time in terms of machinery, chemical applications, harvesting, storage, etc.), it is an ecological recipe for disaster.  The plants in a field - often genetically identical - require the exact same nutrients and extract these quickly from the soil.  This means that fertilizers must be applied to replenish the soil.  In a natural grassland, the many types of plants all have slightly different nutrient requirements and some actually add to the nutrient stores of certain minerals in the soil).  In addition, having a monoculture in a field is an invitation for pest and disease species.  I think a blind corn rootworm could fold its wings and  fall out of the sky over Indiana (animation) and have a 50% chance of hitting a cornfield (and a 50% chance of hitting soybean).  Pests, once they reach a field, are able to multiply and spread rapidly, thus introducing the need for pesticides.  A natural grassland makes it difficult for pests to seek out their host plants among the diversity; in addition, the natural grassland is host to a lot of predatory insects which further reduce pest populations.  

Cornfield, Jasper County, Indiana

Cornfield, Jasper County, Indiana

Modern agriculture does make some nods to these problems.  Crop rotation, where one crop is grown in a field one year and another crop the next, does much to combat the worst problems of pest buildup and soil nutrient exhaustion in fields.  In many cases, corn is rotated with soybeans; the latter are legumes which harbor Rhizobium, an endosymbiotic bacterium which converts atmospheric nitrogen into a form that plants can use to make proteins.  In this way, planting soybeans (or alfalfa) may increase the nitrogen content of the soil and reduce the need for nitrogen-based fertilizers.

In any event, agricultural systems displace natural communities; given the world's need for food to feed the human population (and we're now raising corn to convert into ethanol to fuel our cars!) this is not due to change anytime soon.

As an aside, it should be pointed out that not all of our agriculture is for food.  Cotton, Flax and Hemp (left) are all raised primarily for their fibers, which we use in clothing.  Industrial hemp, which is produced from a version of the cannabis plant (Cannabis sativa, left).  During World War II, disruption of imports of the raw materials used to make rope caused farmers in the United States to plant hemp, whose fibers can be used to make rope (this cultivar also has far less of the active ingredient THC, which makes other cultivars of cannabis attractive as a drug).  The plant escaped cultivation, and even when the Indiana farmers completed their patriotic duty of growing hemp for Uncle Sam and the area returned to corn and soybean farming, "wild" cannabis was still to be found all over the countryside.  Before you email the DEA, the plant at left was growing in the barnyard of a deputy sheriff who has been vigorously trying to eradicate it from his land.  It's also interesting that when you look at the web sites devoted to cannabis they all make a big fuss out of all the uses the plant can be put to, but when you come right down to it, the main reason they are pushing for reform of the existing laws (which make the cultivation even of industrial hemp illegal) is because they want to get high. It really reminds one of all the wonderful things you promise your parents you'll do when you are allowed to drive (taking younger siblings to practice, doing the shopping, etc.) that seem to be forgotten once one actually has the license in hand.

Today, a top area of research is prairie restoration.  To accomplish this, invasive and non-native species must be removed, and native species planted and maintained.  One of the toughest problems is to get seeds from plant communities that have largely been eliminated by agriculture.  Interestingly, among the best places to find remnants of the prairie - and the seeds - is in old cemeteries and along railroad right-of-ways.  Both of these places have largely been ignored and many of the "weeds" growing in these unkempt areas are actually our few remaining prairie plants.  Once the seeds have been harvested and planted, a restored prairie needs maintenance. Most restored prairies are burned periodically, a practice known as prescribed burning, to kill shrubs and trees that would otherwise move the prairie to forest.  An intact natural ecosystem is often very resistant to invasive species, so once restored the prairie is relatively stable as long as it gets its fire.  Because some of these restored prairies are close to communities (where the smoke and danger of the fires burning houses are a concern) some prairie managers are looking at alternative methods such as mowing.  Whether fire or mowing is used, care must be taken to time the event so that it doesn't cause disruption to key species in the ecosystem.  For instance, you wouldn't want to do a burn when ground-nesting birds are on their nests. 

Tour:

Cheetah (Acinonyx jubatus) - San Diego Wild Animal Park

Cheetah (Acinonyx jubatus) - San Diego Wild Animal Park

African Elephant (Loxodonta africana)

African Elephant (Loxodonta africana)  

Cheetah (Acinonyx jubatus) - Cleveland Metroparks Zo

Cheetah (Acinonyx jubatus) - Cleveland Metroparks Zoo

The cheetah (left) is perhaps the cat best adapted to the grasslands.  With its high top speed (several sources list about 70 mph (112 kph)) it can catch just about any other animal; however it can't sustain this speed for long.  It preys primarily on smaller antelopes and gazelles. Cheetahs are critically endangered. The lion (below left) is not as fast, but it can take down larger prey, particularly when it works with other lions.  Even so, much of a lion's diet can come from scavenging the kills of other creatures.  

Adult elephants (above right) are pretty much immune from predation, and because of their social structure, the young are pretty well protected, too. For a predator to approach a young elephant it would normally have to fight its way through the mother and a few aunts or sisters, and perhaps even a bull or two.  When elephants get p****d they just step on things, and those things usually break.  Elephants can also have a tremendous impact (literally) on the environment, as heavily trod areas (such as near a water hole) can become devoid of plant life.

The ostrich (below) is native to Africa. The other large ratites (flightless birds) of the southern hemisphere are the rhea (South America) and Emu (Australia) (as well as the smaller kiwis and cassowaries), all apparently descended from a common ancestor that lived while those continents were still joined about 170 MYA (million years ago), although some modern DNA evidence sheds doubt on this.  These birds are mostly herbivorous, focusing particularly on seeds, although insects and small animals are also eaten.  

African Lion (Panthera leo), Cleveland Metroparks Zoo

African Lion (Panthera leo), Cleveland Metroparks Zoo

Ostrich (Struthio camelus) - Cleveland Metroparks Zoo

Ostrich (Struthio camelus) - Cleveland Metroparks Zoo

Black Rhinoceros - Diceros bicornis

Black Rhinoceros - Diceros bicornis - Cleveland Metroparks Zoo

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

 

Rhinoceroses: These unusual mammals are found in Africa, India, Southeast Asia and Indonesia.  The two African species are the most grassland-loving species, and they each have a distinct ecological role.  The black rhino (above) has a prehensile upper lip that it uses to browse (pick off leaves) from low-growing plants.  There are about 3,000 of these rhinos left in the wild.  The white rhino (right and below) is more common (about 12,000 individuals) and has a wider lip.  In fact, the name "white rhino" probably is a mistranslation of the Boer word "whit" which means wide (and the black rhino was named just to contrast with the white, both species are gray). The white rhino is a grazer.  With both species feeding in different ways, it is possible for them to co-exist in an area.  A rhino can run about 30 miles an hour, and in contrast to the impression left by a car commercial, they can turn on a dime.  Their thick hides help armor them, and the horns make a formidable defense (and as the photo below shows, sneaking up behind a rhino won't do you much good either).  Rhinos have an excellent sense of hearing (note the ears, which can swivel to listen all around the animal) and smell.  They've taken a rap for having poor eyesight, but that is probably a relative thing.

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Southern White Rhino (Ceratotherium simum simum) - The Wilds, Ohio

Cattle egret Bubulcus ibis

Cattle egret (Bubulcus ibis) - Florida

 

Bobwhite Quail (Colinus virginianus) - Archbold Biological Station, Florida

 

Bobwhite Quail (Colinus virginianus) - Archbold Biological Station, Florida

 

Killdeer (Charadrius vociferus)

 Killdeer (Charadrius vociferus)

Birds are common in grassland areas where they fill a variety of ecological roles.  The Bobwhite Quail consumes seeds and insects and lives mostly on the ground.  The Cattle Egret is an interesting story.  In its native Africa, this bird follows large herds of mammals, feeding on the insects disturbed by the herbivores.  They apparently crossed the ocean from Africa to South America in the late 1800's and reached the US by the 1940's.  Wherever they end up, their basic habit of following herbivores (usually cows) remains, but I have seen them in Florida following tractors mowing the grass along highways.  

The Killdeer (left) is normally dependent on rivers for its nesting ground, as they prefer to nest on open gravel areas, and the banks of a river after a spring flood fit this bill.  Closely related to various shorebirds, the killdeer follows the general killdeer habit of feeding on invertebrates gleaned from the ground.  Humans have made the killdeer's life easier, with our tendency to build gravel roads and even put gravel on their roofs.  This has allowed these birds to make further inroads into grassland areas as opposed to the areas right along rivers.

The Sandhill Crane is a large, majestic bird that feeds on insects and other small animals, as well as grains and other vegetable matter.  Like the killdeer, the cranes rely on rivers as a conduit into the middle of areas like grasslands.  The picture below of the Ladybird Beetle is mostly for show.  Larvae of these beetles feed on aphids which in turn feed on the grassland plants.

Sandhill crane (Grus canadensis) - Dundee, Florida

Sandhill crane (Grus canadensis) - Dundee, Florida

Ladybird Beetle (Coccinellidae)  on Goldenrod (Solidago sp.)

Ladybird Beetle (Coccinellidae)  on Goldenrod (Solidago sp.)

Persian Onager (Equus hemionus onager), The Wilds, Ohio.

Persian Onager (Equus hemionus onager), The Wilds, Ohio.

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

Horses of all types are excellent examples of grassland animals.  Strong runners, they are able to kick, bite, stomp and otherwise trample predators; in addition they often live in herds which increases their ability to deal with predators.  The inset picture here has been emailed all over the internet and appears on a number of websites, so I don't feel too bad in blatantly stealing it to make the point here.  That is a mule, and it has picked up and is swinging a mountain lion.  Many of the stories accompanying the photos around the internet claim the mule killed the lion; most of the commentary seems to indicate that while this is possible in this case the lion was already dead.  The point, of course, is that a horse isn't as helpless as it might first appear.

Most "wild" horses around the world (lower right) are actually feral, that is they are descendents of domesticated horses which escaped from captivity.  Still, wild horses exist in the world - barely.  Przewalski's horse was briefly extirpated from the wild but has been reintroduced from captive (but undomesticated) stock.  In fact, the captive stock had at one point diminished to 13 individuals; all of the existing Przewalski's horses are descendents from them.  Zebras, of course are cogeners with the horse, Equus caballus, Przewalski's horses are a subspecies of the modern horse and its only living wild ancestor.  Another cogeneric horse is the Persian Onager (above), which is also critically endangered.

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

Przewalski's horse (Equus caballus przewalskii), The Wilds, Ohio.

 

Hartmannís mountain zebra (Equus zebra hartmannae), The Wilds, Ohio

Hartmannís mountain zebra (Equus zebra hartmannae), The Wilds, Ohio

 

Feral Horses - Equus caballus

Feral Horses - Equus caballus - Theodore Roosevelt NP

Red-tailed Hawk  (Buteo jamaicensis)

Red-tailed Hawk  (Buteo jamaicensis)

 

Red-tailed Hawk  (Buteo jamaicensis)

Red-tailed Hawk  (Buteo jamaicensis)

Red-tailed Hawk  (Buteo jamaicensis) (juvenile) - Marietta College Campus
Red-tailed Hawk  (Buteo jamaicensis) (juvenile) - Marietta College Campus

Predatory birds are important in grasslands; certainly the open vistas make it easier for them to spot their prey, and there aren't a lot of trees for a large bird to weave through. The Red-tailed Hawk is a good example.  Note the sharp claws (talons), forward-directed eyes (for binocular vision), and sharp beak.  The ability to soar on rising thermals (above) enable these birds to spot prey on the wing in an area where trees and power lines aren't handy.

Goldenrod is a plant the invades open areas in forests and which also forms a part of the grassland community.  Goldenrod is insect-pollinated; while it is often blamed for allergies, that is not the case as the heavy, sticky pollen doesn't travel far from the plant on its own (ragweed "blooms" at the same time and its wind-spread pollen is responsible for most hayfever.).

Goldenrod (Solidago sp.) Marietta Ohio

Goldenrod (Solidago sp.) Marietta Ohio

Monarch (Danaus plexippus) on Goldenrod (Solidago sp.) Marietta Ohio

Monarch (Danaus plexippus) on Goldenrod (Solidago sp.) Marietta Ohio

Monarch Caterpillar (Danaus plexippus)

Monarch (Danaus plexippus) Chrysalis - lateral view

Monarch (Danaus plexippus) Chrysalis - lateral view

The migratory Monarch Butterfly is part of the grassland ecosystem.  The larvae (above) are able to feed on toxic milkweed and incorporate the toxins into its body.  The larvae eventually reaches the pupal stage, which it passes in the chrysalis stage (right) suspended from a twig.  During this time, the larvae transforms into an adult (lower right), which then emerges.  The monarch is well known because of its migratory habits.  From an overwintering site in the Mexican mountains, this butterfly moves north on spring storms, laying eggs as it goes.  Eventually, these eggs hatch out and develop, and in the fall the process reverses and the butterflies move south.

Everyone "knows" the monarch is poisonous (have you ever tasted one?), but the story of the viceroy (below left)  is not as clear.  Obviously, the monarch and the viceroy resemble each other.  The classic explanation is that the viceroy is a harmless mimic of the toxic monarch (the model) in an example of Batesian Mimicry.  There is a problem with this explanation, however.  When doing the original experiments, the researchers "knew" to feed the monarchs milkweed, and as a result they all grew up toxic.  On the other hand, the viceroy is found on a number of food plants, and the researchers resorted to a rather bland caterpillar chow to raise those larvae.  They then tested the adults of both species using Blue Jays.  The jays would happily down viceroys until they got their first monarch; at that time they'd vomit and refuse to eat either butterfly.  Thus the legend was born.  Later, it was discovered that in the wild many viceroys actually feed on a number of poisonous plants, with the result that many of the viceroys in nature are as poisonous as a monarch would be.  This makes it simpler for the birds, too, which have only one pattern to remember (we don't have the expression "bird-brain" for nothing).  This is an example of Mullerian Mimicry, where both species are models (and poisonous or distasteful).

Monarch (Danaus plexippus) Chrysalis - ventral view

Monarch (Danaus plexippus) Chrysalis - ventral view

Viceroy Butterfly  (Limenitis archippus)

Viceroy Butterfly  (Limenitis archippus)

Monarch (Danaus plexippus) Adult

Monarch (Danaus plexippus) Adult 

Milkweed Bug - Oncopeltus fasciatus on Milkweed (Asclepias sp.)

Milkweed Bug - Oncopeltus fasciatus - on Milkweed (Asclepias sp.) 

Viceroy Butterfly  (Limenitis archippus)

Viceroy Butterfly  (Limenitis archippus)

Milkweed Bug - Oncopeltus fasciatus on Milkweed (Asclepias sp.)

Milkweed Bug - Oncopeltus fasciatus - on Milkweed (Asclepias sp.) 

More on Milkweed.  The Milkweed Bug is another species that is able to get past - and even exploit - the milkweeds formidable chemical defenses.  The primary food source are  the seeds.  This explains why you often see the bugs congregated on the seed pods.  The bugs can use their long proboscis to penetrate the pod and feed on the seeds inside. They inject a salivary juice with digestive enzymes to dissolve the seed and suck out the resulting liquid; in the laboratory these bugs can be reared on shelled sunflower seeds (the seed coat of the sunflower seed is too much for the proboscis to handle). In the image to the left you can see a number of nymphs of this insect at various stages of development. In the photo at the bottom left the brown seeds are exposed along with the fibrous tufts that will help the seeds soar through the air. The small size of the seeds mean many can be produced; the long hairs help the winds scatter the seeds.  These qualities help the milkweed quickly colonize new habitats wherever the grassland is disturbed.  Below, a milkweed relative, the Dogbane plant has seed pods which are very long and slender compared to those of the milkweed. Like the milkweed, dogbane has its own set of insects uniquely adapted to feed on its poisonous tissue; these include the beautiful Dogbane Leaf Beetle with its shiny metallic body.

 

 

 Milkweed seeds (Asclepias sp.)

 Milkweed seeds (Asclepias sp.) 

Dogbane (Apocynum cannabinum) Seed Pods

Dogbane (Apocynum cannabinum) Seed Pods

Dogbane Leaf Beetle - Chrysochus auratus

Dogbane Leaf Beetle - Chrysochus auratus

 

Garter Snake - Thamnophis sp.

Garter Snake - Thamnophis sp.

Garter Snake - Thamnophis sp.

Garter Snake - Thamnophis sp.

Garter

Garter

Tick

Tick

Snakes are well-adapted to live in grasslands since their long skinny bodies have no protruding limbs to snag as they slither through the thick plant growth.  The various species of Garter Snakes are particularly associated with the grassland habitat in North America. They feed primarily on insects and earthworms, as well as small amphibians and, for more aquatic species, fish.  They compete for box turtles for a lot of the same food items and box turtles DO NOT LIKE THEM (except as an entree).  That's right, box turtles eat garter snakes. That's GARTER NOT GARDEN snake, by the way.  They were named for the bright longitudinal ribbons of color that some garter snakes displayed; these reminded some of men's garters (left), which were bands of cloth (often brightly colored) which were used to hold up a man's stockings before elastic was invented (or after the elastic had given out).  Needless to say, the only exposure most Americans today have to a garter is a frilly white piece of elastic hanging from the rear-view mirror of vehicles driven by (slightly) post adolescent males.  So, it's not surprising that more and more people are calling these garden snakes, because, after all, most people see the snakes in their gardens and they've never seen a multicolored, striped garter.  If you don't believe me that people are confusing the name, do a google image search on "garden snakes" and you'll get pictures of garter snakes.  Fortunately, if you do a search on garters you'll get pictures of garter snakes mixed in with the apparell.  Kids, be sure safe search is on for this one. Thanks to Wayne at Wayne Zurl Historical Reproductions for the picture of the garter.

Enough etymology, on to entomology.  The grasshopper is probably the insect most associated with the grasslands (what with its name and all), but the truth is a lot of insects find the grasslands home.  Grasshoppers, with their saltorial (jumping) hind legs are able to quickly escape a predator like a snake; they are willing to sacrifice one of the legs to get away, too.  Ticks are not insects, of course, but they may be very common in grasslands where they wait patiently on a plant for a mammal to pass by.  Then, they release the grass, jump onto the mammal, and suck its blood.  In Africa the Tick Birds rides around on rhinos just waiting for a tick to try this stunt.  

The Goldfinch is a very attractive bird which feeds on thistle seeds.  I've looked at many of the thistle heads that the birds were feeding on and found often infested with various insect larvae, I wonder if the birds don't get some protein with their seeds?

Grasshopper - Acrididae

Grasshopper - Acrididae

American Goldfinch  - Carduelis tristis

American Goldfinch  - Carduelis tristis

 

Bison (Bison bison) on the range, Theodore Roosevelt National Park, North Dakota

Bison (Bison bison) on the range, Theodore Roosevelt National Park, North Dakota

Grassland, North Dakota

Grassland, North Dakota

Shortgrass Prairie - This very dry grassland do not grow the tall grasses that are found further east.  Diversity is lower as well.  Among the inhabitants of this community is the Prairie Dog (below right).  This burrowing rodent lives in extensive communities often called prairie dog towns.  Because of their supposed detrimental effect (usually overstated) on cattle, prairie dogs have been extensively hunted and poisoned, with the result that prairie dog towns are now rare, and species that depend on prairie dogs like the black-footed ferret are near extinction.

You've seen (or will see) Grouse on a number of these pages.  It seems every habitat has its grouse, and the plains are no exception.  The birds pictured here are probably Sage Grouse, but the light was poor that morning and the scan of the original slide just isn't good enough to say for sure.

Grassland, Nebraska

Grassland, Nebraska

Grouse (probably Sage Grouse) - Theodore Roosevelt NP, North Dakota

Grouse (probably Sage Grouse) - Theodore Roosevelt NP, North Dakota

Black-tailed prairie dog (Cynomys ludovicianus)

Black-tailed prairie dog (Cynomys ludovicianus)
Theodore Roosevelt National Park

Oryx (Gemsbock ) Oryx gazella - The Wilds, Ohio

Oryx (Gemsbock ) Oryx gazella - The Wilds, Ohio

Oryx (Gemsbock ) Oryx gazella - The Wilds, Ohio

Oryx (Gemsbock ) Oryx gazella - The Wilds, Ohio

Pronghorn herd

Pronghorn - Antilocapra americana - Big Timber, Montana

Antelope, gemsbock, springbok, gazelles, wildebeest, gnus and other ungulates are common to grasslands the world over.  The basic body plan makes sense for a herbivore on the grasslands.  The gemsbock or Oryx (one of several subspecies) is an endangered species from Africa.  On the great plains of the United States, the pronghorn, with its distinctive white underbelly and the forward-slanting horns of the males, is a common sight.  It is not an antelope (nor a goat, as some think) but a member of a taxonomically distincxt family.  It has horns that look like antlers because they are branched (antlers are composed of bone and are shed once a year; horns are made of compressed hair (like a fingernail) and are not shed), and to complicate matters the pronghorn uniquely sheds its horns.  In any event, these guys are fast.  The top speed is disputed, but while a cheetah may be able to out sprint them, a pronghorn can run for miles at speeds of 30 mph (50 kph).  Read more about proghorns here.

Pronghorn

Pronghorn - Antilocapra americana - National Bison Range, Montana

 

 

pronghorn

Pronghorn - Antilocapra americana - Big Timber, Montana

Bison (Bison bison)

Bison (Bison bison

Bison (Bison bison) on the range, National Bison Refuge, Montana

Bison (Bison bison) on the range, National Bison Range, Montana

Some writers correctly point out that the pronghorn is better described as the archetypical animal of the plains since it only exists in the prairies and the deserts surrounding them, as opposed to the bison which was also found in the eastern forests.  Still, it's hard not to think of the plains without thinking of the bison.  A herd of over 30,000,000 (that's 30 million) once roamed the Great Plains, migrating north with the melting snow and south with the coming winter.  Additional animals lived in smaller herds in forest clearings throughout the eastern United States.  The large bison herd was a mainstay of the plains Indians who followed the herds and obtained not only meat but clothing and tents from the animals (a parasitic bird, the brown-headed cowbird did much the same, with its nomadic ways the cowbirds couldn't stop to sit on their eggs so they outsourced this job to the unwitting birds whose nests they laid their eggs in).  European settlers moving into the plains in the 1860's began to decimate the herd; many animals were killed for just the tongue meat - or simply shot, perhaps in an attempt to remove the plains Indians by removing their food source.  In any event, by the 1880's only a few wild buffalo were present in Yellowstone, with some more in Canada and a few on a ranch in the Flathead Valley of Montana.  The government bought the ranch and its herd and the National Bison Refuge was established.  The quarter million or so bison today (a few in the wild, the rest being ranched for their meat) are the descendents of those few remnants.

Bison (Bison bison) on the range, National Bison Refuge, Wyoming

Bison (Bison bison) on the range, National Bison Range, Wyoming

Bison (Bison bison) on the range, Theodore Roosevelt National Park, North Dakota

Bison (Bison bison) on the range, 
Theodore Roosevelt National Park, North Dakota

Bison (Bison bison) on the range, National Bison Refuge, Wyoming
Bison (Bison bison) on the range, National Bison Range, Wyoming
National Bison Range

National Bison Range

View of Flathead Valley from National Bison Range

View of Flathead Valley from National Bison Range

Conservation of grasslands - particularly large unfenced grasslands where migratory wild grassland animals can move with the seasons - is a particular challenge in today's world with its heavy demand for food.  The National Bison Refuge, sitting on the edge of the heavily farmed Flathead Valley in Montana, shows one approach to grassland conservation - buy it up and protect it.  With the value of agricultural land, however, this isn't always an option.  Another innovative experiment is underway in southeastern Ohio, where The Wilds came to be in the early 1990's.  American Electric Power once owned and mined tens of thousands of acres of coal here; one of the tools of that trade was Big Muskie, the largest dragline (some say the largest machine capable of moving on land) ever (right).  In any event, AEP decided to donate over 10,000 acres of reclaimed strip mine land (below) to a consortium of zoos; this development later became known as the Wilds, a center for wildlife conservation.  With pastures the size of most city zoos, the Wilds can put whole herds of endangered species into a field together and allow them to have a much more natural existence than is possible in a traditional zoo.  It is hoped that this will help reproduction in those species, and it gives scientists a chance to observe "natural" behavior that is not possible in smaller settings.  Marietta College has worked with the Wilds since its founding; if you find yourself driving Interstates 70 or 77 through the state you owe it to yourself to stop and visit the Wilds.  Perhaps you'll meet one of our students working as a naturalist, camp counselor, conservation intern or tour guide.

Big Muskie - Ohio

Big Muskie - Ohio

The Wilds, Ohio

The Wilds, Ohio

The Wilds, Ohio

The Wilds, Ohio

In Ohio the traditional practice after strip mining is to try to restore the land to native forest, a task that has proven to be very difficult.  At the Wilds, the first restoration attempt was to cover the land with grasses, and most of the land is still that way today.  This brings up an interesting debate - should restoration proceed to the forest stage, should natural selection be allowed to take the grassland back to forest, or should the grasslands be actively managed as such?  One of the reasons for maintaining a grassland where forest once stood is that in Ohio many grassland species, particularly birds, are on the decline.  In 1900, only about 6% of Ohio's forests remained, with the rest devoted to agriculture, and a significant portion of that to grasslands used to pasture horses.  The automobile and tractor eliminated the need for horse pasture and the Great Depression ended many of the smaller farms in the southern, unglaciated, hilly part of the state.  Today, almost 40% of the state is forest, particularly in the south, and grassland in any condition, let alone natural, is rare.  Plans at the Wilds are to maintain significant areas of grassland, and to try to improve the grassland by eliminating introduced species and replacing them with native prairie plants.

Grant's Zebra (Equus burchelli bohmi) Lowry Park Zoo, Florida

Grant's Zebra (Equus burchelli bohmi) Lowry Park Zoo, Florida

Hartmannís mountain zebra (Equus zebra hartmannae), The Wilds, Ohio

Hartmannís mountain zebra (Equus zebra hartmannae), The Wilds, Ohio

Warthog (Phacochoerus aethiopicus) - Lowry Park Zoo, Tampa, Florida

Warthog (Phacochoerus aethiopicus) - Lowry Park Zoo, Tampa, Florida

 

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