Ecosystem Ecology through Forest Ecology
Presented by R. Craig Hensley, Park Interpreter & Naturalist Guadalupe River State Park & Honey Creek State Natural Area Texas Parks and Wildlife Department
Saturday, October 21, 2017 Master Naturalist Statewide Conference Corpus Christi, TX Ecology: What It Is
Derived from the Greek “oikos” meaning “house” or “place to live.” “ology” means “the study of” Literally, ecology is the study of organisms “at home.” Ecological Components include: - Biotic – Plants, Animals, “other organisms” - Abiotic – Water, Rocks, Soil, Air, Chemicals - Interactions – Biotic and Abiotic - Interrelationships – Plants and Plants, Animals and Animals, Plants and Animals, Biotic and Abiotic - Human Beings “The outstanding scientific discovery of the twentieth century is not television, or radio, but rather the complexity of the land organism. Only those who know the most about it can appreciate how little is known about it. The last word in ignorance is the man who says of an animal or plant: ‘What good is it?’ If the land mechanism as a whole is good, then every part is good, whether we understand it or not. If the biota, in the course of aeons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the first precaution of intelligent tinkering.” - Aldo Leopold Definitions of Ecology
Ecology was originally defined in the mid-19th century by Ernst Haeckel as: “the study of the relationship of organisms with their environment.”
The second definition of ecology, provided by Andrewartha and Birch (1954) was: “the study of the distribution and abundance of organisms.”
The third, put forth by Eugene Odum (1971) was: “The study of the structure and function of nature,” “…it being understood that mankind is a part of nature.”
In it’s simplest form, Odum defined ecology as “environmental biology.” The definition as written by the Institute of Ecosystem Studies is: “The scientific study of the processes influencing the distribution and abundance of organisms, the interactions among organisms, and the interactions between organisms and the transformation and flux of energy and matter.” Seven Principles of Ecology
Principle 1: The plant or producer, the grazing animal or consumer and the intrinsic value of a healthy ecosystem need to be looked at together, not separately. Principle 2: The natural resource manager should understand change and know it has an influence on all of his (her) management decisions. Principle 3: For every action on the land, there are multiple reactions which can occur. Principle 4: Nature abhors a void and provides plants through the processes of primary and secondary succession to fill the openness. Principle 5: Humans have found that Nature knows best. Organisms which are suited and adapted to the change, occupy the site. Principle 6: “Everything must go somewhere.” Principle 7: “there is no such thing as a free lunch.” Ecosystem
The ecosystem is the basic functional unit in ecology It includes both organisms and the abiotic environment These influence the properties of the other and both are necessary for the maintenance of life on Earth Ecosystem Components
1. Inorganic substances (C, N, CO2, H20, etc.) 2. Organic Compounds (proteins, carbohydrates, lipids, etc.) 3. Climate Regime (temperature and other physical factors) 4. Producers (autotrophic organisms, i.e. green plants) 5. Macroconsumers (heterotrophic organisms, i.e. animals) 6. Microconsumers (heterotrophic organisms, i.e. bacteria and fungi – decomposers) Important Abiotic Factors
Light Temperature Oxygen Level Air Circulation Precipitation Soil Type Producers: Autotrophs
“Self-feeding” Utilize the sun’s energy and convert it, along with CO2 and H20, to sugar for their growth and survival General rule of thumb is that if there are no producers, there are no consumers Consumers: Heterotrophs
Two levels Those that eat other organisms or organic matter – the macroconsumers Those (bacteria and fungi) which break down dead organisms, absorbing some of the by-products of decomposition and releasing both organic and inorganic substances for use by producers – the microconsumers Primary Consumers
those organisms that feed directly on plants Secondary Consumers
Those animals that consume other consumers Energy Flow within an Ecosystem
Energy flows in one direction == from the sun to the producers to the consumers Sun Plant Animal= Food Chain
Food Web
Sun
Oak Tree Compass Plant Milkweed
Fox Squirrel Monarch Caterpillar Grasshopper Deer
Bull Snake Bluebird Coyote
Great-horned Owl Watching over it all…
…not to mention uncountable numbers of bacteria and fungi! Forest Ecology: An Introduction Forest Ecology is the study of the forest as a biological community along with the interactions between species and the physical environment.
Forested Regions of Texas include: 1. Pineywoods (12.1 million acres of East Texas) 2. Live Oak-Juniper (Hill Country/Edwards Plateau) 3. Post Oak Savannah 4. East Cross Timbers 5. West Cross Timbers 6. Mountain Forests Principles of Succession
First Rule of Nature: Nature is dynamic
Succession is a process of change that tends to occur in an orderly direction but can be interrupted through both man-made and natural disturbance
Succession is a gradual, on-going and long-term process
Remember: Succession involves fauna as well as flora Layers of a Forest
Modified from graphic of the Chesapeake Ecology Center Faunal Layers Seasonal Changes in a Forest Cross Timbers
These forested areas got their name from pioneers who crossed through “bands” of forest between grasslands
The cross timbers of Texas are an extension of the oak forests that extend back through Oklahoma to the Ozarks of Missouri and Arkansas Cross Timbers
Dominated by blackjack and post oak Cross Timbers
Post oaks tend to be more drought resistant and fire resistant
Blackjack oaks tend to sucker sprout better following fire; shorter in stature
Fire resistance is high for older trees due to thick bark; do have ability to re-sprout quickly
Fire enhances seedling production as a clean ground cover allows for more acorn caching by bluejays and squirrels Cross Timbers
Historically, the cross timbers were thought to be a mosaic of prairie, savanna, oak mottes, and dense oak woodlands; the general conclusion is that the area prior to European settlement was savanna due to periodic fires
The biggest challenge to the cross timbers is in terms of vegetation is “invasion” of eastern red cedar Edwards Plateau
Characterized by limestone-covered land, deep canyons and ravines forged by streams and rivers;
Throughout the area are springs and seeps that feed those streams;
What much of it looks like today is very different from 200 years ago
Generally known as the “Hill Country”
Agarita
Texas Persimon
Wafer Ash
Texas Redbud Characteristic Floodplain Flora Includes:
Bald Cypress Sycamore
Texas (Little) Walnut Edwards Plateau
The area has become overrun by two species of cedar:
Ashe Juniper Red Berry Juniper What is Management?
The use of certain means to achieve desired results. Management is planning, establishing goals, evaluating alternatives, making decisions then implementing those decisions within budget and time constraints – and then monitoring, adjusting and re-planning. Management must consider both the short- term and long-term goals. What Management is Not
“I was young then, and full of trigger itch; I thought that because fewer wolves meant more deer, that no wolves would mean hunter’s paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.”
- Aldo Leopold Ecosystem Management
It looks at the greater whole rather than individual species; It requires and takes a long-term approach to results from today’s actions It cannot be done once It requires consensus and community buy-in (the community being all the partners from the general public to individual agencies) It requires using natural processes when possible to facilitate desired outcomes It requires humans to stand back at times and let the natural world do the work It requires a long-term investment It must be monitored, assessed and when necessary, changes to plans made for the betterment of the greater goals Juniper Ecology*
Widespread expansion of both species is thought to have occurred due to overgrazing and suppression of fire;
Historic distribution restricted to rocky outcrops and rocky, north-facing slopes;
Red berry juniper readily sucker sprouts when cut while Ashe juniper does not
*Summarized from Allan McGinty’s article “Juniper ecology”; Texas A&M Ag Extension Juniper Ecology
Junipers are used for food by white- tailed deer, ringtails, raccoons, gray fox
Junipers are used by 18 species of birds including cedar waxwings and robins
Junipers provide wildlife cover but much can be removed without negatively impacting deer cover Juniper Ecology
Junipers are required for nests of the Golden- cheeked warbler
Black-capped vireos are also associated with junipers but are not dependent on them 2015 GCWA Survey
Closing Thoughts
“Ecosystem management is a ‘state of mind’.” It is a way to view things so that you consider what effects your actions may have on other organisms and parts of the natural ecosystem you are associated with and managing.”
It really boils down to intelligent tinkering by caring and thoughtful stewards, whether a rancher, land manager, backyard nature enthusiast or corporate leader.
We have the technology and knowledge to effect positive changes for the long-term benefit of the global ecosystem – the real question is do we have the will and commitment to see it through? Thank you