Comprehensive Laboratory Study on Terrestrial and Riparian Ecosystems

Terrestrial Analysis and Ecosystem Biotic Components

Ecosystem Composition: An ecosystem is comprised of biotic (living) components, which are categorized according to their trophic level:

Trophic Level Definition:

A trophic level refers to the position an organism occupies in a food chain, typically classified into producers, consumers, and decomposers.

Producers (Trophic Level 1): Organisms that create their food through photosynthesis or chemosynthesis, such as plants and algae.
Primary Consumers (Trophic Level 2): Herbivores that consume producers, like rabbits and deer.
Secondary Consumers (Trophic Level 3): Carnivores that eat primary consumers, such as foxes and snakes.
Tertiary Consumers (Trophic Level 4): Apex predators that are not typically preyed upon, including eagles and large cats.
Decomposers: Organisms such as fungi and bacteria that break down dead organic matter, recycling nutrients back into the ecosystem.

Producers: These organisms utilize light energy from the sun to synthesize organic matter from inorganic nutrients. They constitute the trophic level that is typically the most numerous in an ecosystem.
Decomposers: Organisms that break down dead organic matter.

Evaluation of Animal Presence 🇦

Animal signs include skeletal remains, tracks, and scat (feces).
Scat Analysis: Used to evaluate the diet of an animal and its relative size.

Interactions, Reproduction, and Biological Cycles

Ecology Defined: The scientific study of interactions between living things (biotic-biotic) and between living things and their physical environment (biotic-abiotic).

Specific Species Interactions:

Mutualism: A relationship where two species live in close association, and both benefit. Example: The "obligate mutualism" between the Yucca plant and the Yucca Moth. Another example is the relationship between the Pinyon Pine and the Pinyon Jay.
Parasitic Relationship: A relationship where an organism lives in or on another species (the host), benefiting at the expense of the host. In some cases, the parasite may kill the host. Example: Juniper mistletoe on Juniper trees, or the relationship between the rabbitbrush and the gall fly, which produces galls on the plant.
Predation: A relationship in which one organism kills and eats another organism.

Modes of Reproduction in Plants:

Monoecious: A single plant possesses both male and female reproductive parts, though they are located in different positions on the plant. Both Pinyon Pines and Junipers can be monoecious, having female cones (for seeds) and male cones (for pollen) on the same plant.
Dioecious: Reproduction requires two separate plants, as each individual plant has exclusively male or exclusively female reproductive parts.
Hermaphrodite: Both male and female reproductive parts are located at the exact same site, such as within the same flower.

Photosynthesis Categories:

C3: Adapted for cool-season growth.
C4: Adapted for warm-season growth.
CAM ( $Crassulacean\,acid\,metabolism$ ): Water-storing plants that are specifically adapted to heat.

Plant Life Cycles and Lifespans:

Annual: Life cycle (germination to death) completed within $1\,year$ .
Biannual: Life cycle completed within $2\,years$ .
Perennial: Life cycle spanning multiple years.

Desert Soil Composition and Community Descriptions

Cryptogamic Soil: A varied composition consisting of filamentous cyanobacteria, green algae, desert moss, and lichens. It serves to limit water runoff, provides a location for seeds to sprout, but is easily disturbed.
Cryptobiotic/Desert Soil Crust: Contains nitrogen-fixing bacteria which enrich the soil's nutrient profile.
Botanical Community Descriptions (Qualitative/Observable):
Sociability: Refers to whether plants are clumped, random, or evenly dispersed.
Vitality: Refers to the health of the plants (e.g., sickly vs. healthy/flourishing).
Stratification: The number of distinct layers or vertical heights present in the plant community.
Fidelity: Refers to the species diversity in a small area (pure stands vs. high diversity).
Aspect: The direction in which the land slopes and its subsequent effect on vegetation.
Grass Growth Forms:
Bunch Grasses: Grasses that grow in distinct clumps.
Carpet Grasses: Spreading grasses that form lawns.

Specialized Terrestrial and Desert Flora

Plants adapted to withstand arid conditions and extreme temperatures often feature deep root systems, water-storing tissues, and a waxy coating to reduce water loss.

Mormon Tea: A native plant in the Bangs Canyon environment that produces a pain-relieving compound in its leaves.
Yuca: A woody shrub native to South America. Its starchy tuberous roots can grow up to 3 feet long and are harvested after a growing period of 8 to 24 months. Is crucial for food security in regions affected by drought and food shortages. Seeds in a yucca plant are primarily dispersed through a mutualistic relationship with the Yucca Moth.
Juniper Tree ( $Juniperus\,osteosperma$ ): Adapted to high desert; produces pollen in male cones and seeds in female cones. Seeds are primarily dispersed by animals (birds eating and defecating seeds). They did not evolve to survive frequent wildfires.
Pinyon Pine Tree ( $Pinus\,edulis$ ): Often found alongside Junipers. Pollen is distributed by wind; seeds are distributed by animals. They can have both male and female cones on the same plant and did not evolve to survive frequent wildfires.

Weeds and Invasive Species:

Weeds and invasive species can outcompete native flora for resources, often thriving in disturbed environments where they can spread rapidly. Their presence can negatively impact the biodiversity of both terrestrial and riparian ecosystems, leading to shifts in plant community composition.
Russian Thistle/Tumbleweed ( $Salsola\,kali\,tragus$ or $Salsola\,iberica$ ): A non-native, invasive plant in western Colorado. It features sharp scale-like leaves and inconspicuous flowers. It has a weak zone at the base of the stem, allowing the entire plant to roll across the ground to disperse seeds.
Cheatgrass: An invasive species that contributes significantly to wildfires.

Lab E: Riparian Ecosystem Characteristics and Functions

Riparian Area Definition: Habitats located along waterways where groundwater is readily available due to a shallow water table.
Characteristics of a Healthy Riparian Area:
High primary (forage) productivity.
Abundance and diversity of wildlife.
Essential for maintaining water quality.
Aesthetic qualities.
Stabilized banks due to dense vegetation roots.
Increased subsurface water storage.

Avian Identification and Nesting Habits

Identification Methods: Requires understanding anatomical terms to describe variations in coloring and markings.
Nesting Sites: Common in tree holes, old tree snags, grassy banks, and abandoned magpie nests.
Nest Types:
Simple: Stick nests.
Complex: Pendulous nests.

Specific Riparian and Desert Birds:

Canada Goose and Mallard (distinct male and female markings).
Wood Duck (distinct male and female markings).
Predators: Red-Tailed Hawk, American Kestrel (male/female), and Bald Eagle.
Owls: Western Screech Owl and Great Horned Owl.
Great Horned Owls use abandoned spherical magpie nests near rivers.
They typically occupy Pinyon-Juniper forests but move to the river to nest. Parents and young return to the high desert forest after the young fledge.

Dichotomous Key for Audubon Nature Trail Plants

Flora Adaptations

Plants in these areas are uniquely adapted to an abundant water supply; many must have roots in direct contact with the water table.

Common Horsetail: Reproduces by spores from a strobilus (cone-like structure); has a hollow, segmented stem.
Big Sagebrush: Fragrant native shrub; leaves have $3$ lobes at the apex.
Rabbitbrush: Native shrub with simple linear leaves and a dense mat of white hairs on the stem.
Box Elder: Tree with opposite, ternately compound leaves (divided into $3$ leaflets). Seeds are encased in a samara and carried by the wind. Native to riparian environments.
Fremont Cottonwood: Native tree with broadly toothed leaf margins and deeply furrowed brown bark. Provides nesting habitat; often has hollowed centers or remains as dead "snags."

Invasive Species in Riparian Areas

Established due to water availability, human introduction, and landscape disturbance.

Russian Olive : Invasive tree with sharp spines and silver pubescence (hairs) on leaves.
Tamarisk Plant/Salt Cedar: Introduced from China as an ornamental and for erosion control. It displaces native species by consuming enormous quantities of water and lowering the water table. It concentrates salts in its leaves; when these leaves drop, they increase soil salinity, making the surface inhospitable for other plants.

Biological Control

A quarter-inch ( $0.25\,inch$ ) black-and-yellow-striped beetle has been released to control tamarisk stands.

Glossary of Botanical Terminology

Alternate Leaves: One leaf per node.
Opposite Leaves: Two leaves per node.
Leaf Margin: The outer edge (entire, serrate, or lobed).
Scale-like Leaves: Greatly reduced leaves.
Simple Leaves: Single undivided blade.
Compound Leaves: Blade divided into separate leaflets (e.g., trifoliolate, palmate, odd/even pinnate).
Inflorescence: A cluster of flowers.
Catkin: Cylindrical cluster for wind pollination.
Samara: A winged, dry fruit.
Spike: Flowers attached directly to the stem.
Strobilus: Cone-like structure for spore production.

Questions & Practice Exam Review

Ecosystem Services: Examples include water purification, shade, crops for consumption, and pollen.
Biodiversity Levels: Three levels: Ecosystem, Species, and Genetic.
Genetic Diversity Case Study: The banana variety associated with banana candy was decimated by a single blight due to a lack of genetic diversity.
Practical Remains: A "Paleo-midden" found in Bangs Canyon was created by a Pack Rat.