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TRANSCRIPT
Plant EcologyPlant Ecology
• Plant ecology is the study of plants in relationship to all aspects of their surroundings.– or, how plants relate to their habitat. So what is
meant by habitat?– Soil (nutrients, pH, texture, structure)
• Water (saline, fresh, plentiful, scarce)• Climate (tropic, sub-tropic, temperate, sub-artic, artic)• Elevation (valley, sea level, hillsides, mountainous)• Competing plant and animal species
There are several plant ecosystems featured above. Try and Identify some. What are the ecosystem factors in the circled area?
Plant PopulationsPlant Populations
• Each plant is surrounded by its own species and others-forms a “plant community”
• When a community comes under the influence of; climate, terrain, soils, water supply and various animals, it becomes an “ecosystem”
Biology of a PopulationBiology of a Population
• Not simply the sum of all plants in a community– Plants interact positively and negatively with
each other• Depend on other members of same species for
cross pollination• Compete with each other for light, water and
nutrients• Left alone, balance will finally be achieved in the
ecosystem
Abiotic and Biotic Components of Abiotic and Biotic Components of the Habitatthe Habitat
• Abiotic-having a non-biological nature, i.e:• Climate• Soil factors• Latitude and altitude• Disturbances-floods, fires, landslides, earthquakes
• Biotic-having a biological nature• The plant itself• Other plant species• Organisms other than plants• Commensal relationships• Predation
Abiotic FeaturesAbiotic FeaturesLet’s look at Let’s look at climateclimate
• Temperature-– plant growth potential in an ecosystem mostly
determined by the days between last frost in spring and first frost in fall.
• Length of growing season must be long enough to allow photosynthesis, growth and reproduction
• Seasonal mean temperature not as important as extremes high and low temperatures.
Climate cont.Climate cont.
• Rainfall– May occur as rain, snow or hail– Habitats range from extremely dry (deserts) to
the opposite end (marshes, lakes, wetlands)– Total precipitation not as important as
distribution.• Pacific Northwest-100 in./year, 0.5 in./day• Southeast Asia-100 in/year, 3 months wet, 9 dry• Would these areas promote similar vegetation?
Let’s look at Let’s look at soil factorssoil factors
• Pioneer plants are the first to “invade” a newly formed soil.– Must be able to tolerate severe conditions– Soil is very sandy, gravel based; minerals
bound in un-dissolved rock– Often associated with N fixing bacteria,i.e.
lichens + cyanobacter (mutualism)– Over time, plants build and decay forming
substrate for bacteria, build up of humus
Let’s look at disturbances-floods, fires, Let’s look at disturbances-floods, fires, landslides, volcanoes, earthquakeslandslides, volcanoes, earthquakes
• Disturbances include fires, landslides snow and floods ( easy to see how they disturb ecosystem)– Capable of rapid change to a plant ecosystem– Pesticides and herbicides and habitat
destruction serve as man made disturbances– Fire can be of great benefit;
• can “open” forest floor to seed bearing food plants for wildlife
• Can reduce competition to established trees by thinning out their competition
A severe natural disturbanceA severe natural disturbance
• (CNN) -- Life has returned, sometimes flourishing, on a mountainside in Washington state where, 20 years ago, a massive sideways blast vaporized forests in 5,000-degree heat and flattened hundreds of miles of timberland.
• Mount St. Helens, whose eruption killed 57 people, many of whom vanished beneath tons of ash, stunned scientists with its ferocity -- so much so that it is now the most studied volcano in the world.
Biotic FeaturesBiotic FeaturesThe plant itselfThe plant itself
• Pioneer plants– Colonize sparse, barren areas. – Their decay enriches the soil– Over time some “N” fixers become established– As ecosystem flourishes, pioneers are no longer competitive
• • Beech/oak forests are mature ecosystems
• Established long after the pioneer plants have done their colonizations
• These trees strongly modify the habitat-produce a dense canopy/ limited sunlight
• Subsequent species on forest floor have a difficult time becoming established.
Other plant speciesOther plant species
• Plant community dynamics– Mutualism; interaction between plants
benefits both organisms– Competition; if interaction between plants not
beneficial– Niche; a segment of the ecosystem
dominated by one species
Organisms other than plantsOrganisms other than plants
• Animals, fungi and bacteria are important components of a plant ecosystem. Relationships can be harmful or beneficial– Commensal relationships; one species
benefits while the other is unaffected– Predation; one species benefits while the
other is harmed
Some species of Central American swollen-thorn acacias lack the chemical defenses of most other acacias to deal with their predators and competition. Without bitter alkaloids, ravaging insects and browsing mammals eat the leaves and branches, slowing the growth of the acacias and allowing fast-growing, competing vegetation to shade them out. Symbiotic ants have taken over this vital defense role, protecting the acacia from hungry herbivores and pruning away competing plants. The ants live inside inflated thorns at the base of leaves.
OutlineOutline
• What are grasslands and Prairies.
• Natural plants.
• Current dominant plants.
• Wildlife.
• Why is soil and land management important?
• What can you do?
DefinitionsDefinitions
• Prairie – a sea of grass
– a grassland region that occurs in the interior of continents.
Rainfall is (generally) too low to support trees and to leach clay and cations from the soil.
DefinitionsDefinitions cont. cont.
• Prairies can be found in Arkansas. The most commonly known prairie region is the Grand Prairie.
• Northwest Arkansas also has pockets of prairie. These small areas are called Glades. Glades are naturally occurring unforested xeric rocky barrens dominated by nonwoody vegetation.
VegetationVegetation
• Grasses– Big Blue Stem– Little Blue Stem – Indian Grass– Eastern Gama Grass– Sideoats Grama Grass– Switch Grass– Tickle Grass– Plus many others
VegetationVegetation cont. cont.
• Forbes– Purple cone flowers– Blue False indigo– Verbena– Ladies tresses orchids– Shooting stars – Poppy mallow– Primrose – And Many others.
VegetationVegetation cont. cont.
• Trees– Eastern Red Cedar– Ashe Juniper– Smoke treee– Skunk bush (aromatic sumac)– Sumac– Oaks (Quercus sp.) only a few sp.– And several others
Current VegetationCurrent Vegetation
• Grasses – Forbes – Trees– Domestic crops such as:
• Rice, Soybeans, Corn, Wheat, and Sorghum
– Pasture• Fescue, and some Bermuda and Alfalfa
– Broom Sage– Lespadeza seretia– Eastern Red Cedar– Winged Elm– And others
Is There a Problem?Is There a Problem?
• Why is there an increasing lack of vegetative diversity?
• Does this influence the diversity of wildlife species?
WildlifeWildlife
• Is wildlife just deer, bear, and turkey?• Do you consider wildlife to be
– Birds• Prairie Chickens• Quail• Pheasants
– Reptiles• Iguanidae - Collard Lizard, Fence Swifts, and Six Lined Race
Runners• Snakes - Coach Whips, Hog Nose, Prairie King, Pigmy Rattlers• Turtles – Painted and Three-toed Box
– Amphibians• Spotted, Slimy, and Tiger Salamanders
Wildlife cont.Wildlife cont.
– Mammals• Voles• Shrews • Mice• Rabbits • Deer• Antelope• Elk• Buffalo
Soil and Land ManagementSoil and Land Management
• Prairie Soils– are (usually) highly fertile– are slightly acidic– have a high organic matter content.
• Combinations of Tillage, pesticide, grazing, and monoculture plantings may– decrease soil fertility– decrease the soils pH– decrease the soils organic matter content.
Soil and Land Management cont.Soil and Land Management cont.
• To maintain soil fertility– Fertilize
• Use animal manures
– pH• Amend the soil with treatments of lime. This Increases the
soil pH, therefore, increasing the availability of soil nutrients.
– Organic matter• Use organic fertilizers• Roll your crop instead of burning
Soil and Land Management cont.Soil and Land Management cont.
• To maintain plant diversity– Don’t introduce plant species like fescue– Leave natural prairie regions alone
• Minimal grazing• If the land is grazed, amend the soil with fertilizers
and lime to maintain healthy natural species.
Note: These recommendations are NOT always possible.
What can you do and why?What can you do and why?
• To maintain natural prairies – Periodic use of fire.– Don’t introduce new species.– Minimal or no grazing– Amend with fertilizers or lime
• Why should you do this?– It retains the natural fertility of the soil– It increases or maintains the prairies plant diversity.– Causing the high diversity of animal species.
Note: When you manage for deer and turkey, this will also increase the populations of other species of wildlife.