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Applications: AGFC Wed site: agfc.com Human resources office: 800-364-4263 Due by June 1!. Plant Ecology. Plant 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?
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Applications: AGFC Wed site: agfc.com Human resources office: 800-364-4263 Due by June 1!
Plant 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 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 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 the 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 FeaturesLet’s look at climate • 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. • 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 soil 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
Early grass colonizing “pioneer plant” on Eldfell volcano in Iceland
Let’s look at disturbances-floods, fires, landslides, 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 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 FeaturesThe 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 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 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.
Grassland and Prairie Ecosystems By Jon Davis
Outline What are grasslands and Prairies. Natural plants. Current dominant plants. Wildlife. Why is soil and land management important? What can you do?
Definitions 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.
Definitions 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.
Vegetation Grasses Big Blue Stem Little Blue Stem Indian Grass Eastern Gama Grass Sideoats Grama Grass Switch Grass Tickle Grass Plus many others
Vegetation cont. Forbes Purple cone flowers Blue False indigo Verbena Ladies tresses orchids Shooting stars Poppy mallow Primrose And Many others.
Vegetation 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 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
