WFC 10 Spring 26 Comprehensive Final Study Guide

Introduction to Restoration and Reconciliation Ecology

• Restoration Ecology: This field involves the scientific study and process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed. It often focuses on returning a landscape to a historical or natural state.
• Reconciliation Ecology: This branch of ecology focuses on establishing and maintaining habitats that conserve species diversity within systems and landscapes that are primarily managed for human use. It acknowledges that human-occupied landscapes can still support biodiversity if designed correctly.
• Conservation Success Example: A classic example includes the recovery of the American Bald Eagle or the California Condor through captive breeding and legislative protection, or the return of the Island Fox in the Channel Islands following the removal of invasive species.

Humans, Wildlife, and Historical Management Eras

• Causes of Species Endangerment: Primary causes include habitat loss and fragmentation, invasive species introduction, pollution, human overpopulation, and overexploitation (hunting/fishing).
• Management Before and After European Contact:     * Pre-Contact: Indigenous populations managed wildlife through controlled burning, selective harvesting, and spiritual practices that maintained ecological balance.     * Post-Contact: European settlers practiced "market hunting," where wildlife was treated as an inexhaustible resource for profit, leading to massive population collapses (e.g., Bison, Passenger Pigeon).
• Eras of Wildlife Management:     * Era of Abundance: Perception of endless resources.     * Era of Overexploitation: Massive declines due to industrial-scale hunting.     * Era of Protection: Focus on laws like the Lacey Act of 1900 and the Migratory Bird Treaty Act.     * Era of Game Management: Aldo Leopold’s influence and the establishment of Pittman-Robertson Act.     * Era of Environmental Management: Expansion to non-game species and ecosystems.

Putah Creek: A Model for Reconciled Ecosystems

• Natural Flow Regime Components: Includes magnitude, frequency, duration, timing, and rate of change of water flow. These elements are vital for triggering spawning in native fish and maintaining riparian vegetation.
• Reconciliation at Putah Creek: The creek is situated between agricultural lands and urban settings. It serves for flood control, irrigation, and recreation. It is reconciled because it is managed to support native fish while serving human needs.
• Wetland Alteration in the Central Valley: Over $90 \%$ of wetlands in California's Central Valley have been lost or converted, primarily for agriculture and development, which has severely reduced native fish populations.
• Hydrology Drivers: Driven by natural precipitation cycles and anthropogenic interventions like the Monticello Dam and seasonal irrigation releases.
• Native vs. Invasive Fish: Restoration efforts at Putah Creek have successfully increased the abundance of native species by mimicking natural flow patterns, which creates conditions that native species are adapted to while disadvantaging invasive species.
• UC Davis Research: Scientists monitor insects, vegetation, and birds to assess ecosystem health; these taxa serve as indicators of biodiversity and the success of restoration strategies.

Evolutionary Biology and Natural Selection

• Darwin's Four Postulates of Natural Selection:     1. Variation: Individuals within a population differ from one another.     2. Inheritance: Some variations are passed from parents to offspring.     3. Overproduction: More offspring are produced than can survive.     4. Differential Fitness: Survival and reproduction are not random; those with favorable traits are more likely to succeed.
• Fitness: The ability of an individual to survive and reproduce in its environment. Fitness is relative to the specific environment; an individual fit in the Arctic may have low fitness in the Tropics.
• Evolution vs. Natural Selection: Evolution is the change in the genetic composition (allele frequencies) of a population over time. Natural selection is the mechanism that drives that change.
• Infectious Diseases: Natural selection helps us understand how pathogens evolve resistance to antibiotics or adapt to jump between host species.

Fundamental Ecology Concepts and Niches

• Key Definitions:     * Ecology: The study of interactions between organisms and their environment.     * Habitat: The physical place where an organism lives.     * Range: The geographic area where a species can be found.     * Generalist: Species with a broad niche (e.g., Raccoons).     * Specialist: Species with a narrow niche (e.g., Koalas).
• Niches:     * Fundamental Niche: The full range of environmental conditions (abiotic and biotic) under which a species can survive and reproduce in the absence of competition/predation.     * Realized Niche: The actual conditions used by a species after taking into account interactions like competition and predation. The fundamental niche is usually larger.
• Interactions:     * Biotic: Living interactions (predation, competition, symbiosis).     * Abiotic: Non-living interactions (temperature, pH, sunlight).     * Interspecific: Between different species.     * Intraspecific: Between individuals of the same species.

Global Climate Patterns and Biomes

• Weather vs. Climate: Weather refers to short-term atmospheric conditions; climate is the long-term average ($30+$ years) of weather patterns.
• Solar Distribution: The Equator receives more direct solar radiation than the poles, leading to higher energy availability and generally higher biodiversity.
• Air and Water: Warmer air can hold more water vapor than cooler air. In a warming climate, this leads to more intense precipitation events in some areas and severe droughts in others.
• The Coriolis Effect: Deviation of moving objects (like wind) caused by Earth's rotation. This creates global wind patterns like the Trade Winds (near the equator) and the Westerlies (at mid-latitudes).
• Coastal Upwelling: Occurs when wind drives surface water away from the coast, replaced by deep, cold, nutrient-rich water. This fuels California's productive marine ecosystems and regulates land temperatures.
• Precipitation Mechanisms:     * Adiabatic Rainfall: Occurs when air rises, cools, and moisture condenses (typically on the windward side of mountains).     * Rainshadow: The dry area on the leeward side of a mountain range.

Niche Applications: Marmots, Amphibians, and Reptiles

• Yellow-Bellied Marmots: Their niche is tied to alpine meadows. Warming causes them to emerge from hibernation earlier. A tradeoff is that early emergence might mean food is not yet available, though it allows more time for growth before the next winter.
• Amphibian Niches: Characterized by a requirement for moisture/water for breeding. Adaptations include permeable skin. Humans introduce invasive species (like trout) that prey on the Mountain Yellow-legged Frog, significantly shrinking its realized niche.
• Reptile Niches: Characterized by ectothermy (reliance on external heat). Adaptations include scales to prevent desiccation and behavioral thermoregulation.

Arctic Ecology and Climate Change

• Arctic Definition: Defined by the area north of the Arctic Circle or temperatures below a certain threshold. Climate change is physically shrinking this definition as temperatures rise.
• Arctic Adaptations: Thick blubber, white camouflage, and specialized metabolic rates.
• Caribou: Negatively impacted by climate change because earlier snowmelts or freezing rain events (rain-on-snow) lock away their food (lichens) under ice.

Fire Ecology

• Fire Regime: The pattern, frequency, and intensity of fire in an area.     * Frequency: How often fire occurs.     * Severity: The impact on the ecosystem/mortality of plants.     * Intensity: The energy released (heat).
• Pyrodiversity: The variety of fire histories within a landscape. This usually increases biodiversity as it creates different successional stages; however, too much high-severity fire can be detrimental.
• Tree Adaptations:     1. Thick Bark: Protects the cambium from heat.     2. Serotinous Cones: Open only in response to fire (e.g., Lodgepole Pine).     3. Self-Pruning: Dropping lower branches to prevent fire from climbing into the canopy (ladder fuels).

Marine Biology and Ocean Acidification

• Intertidal Zones: Characterized by high environmental stress (tides, sun exposure, pounding waves). Vertical zonation occurs based on a species' tolerance to exposure (upper limit) and competition/predation (lower limit).
• Ocean Acidification: Caused by the ocean absorbing excess $CO_2$ from the atmosphere, creating carbonic acid.     * Equation: $CO_2 + H_2O \rightarrow H_2CO_3 \rightarrow H^+ + HCO_3^-$
• Calcifiers: Organisms like oysters, corals, and sea urchins are most affected because acidity reduces the availability of carbonate ions needed to build shells ($CaCO_3$).

Carnivore Ecology and Trophic Cascades

• Regulations:     * Top-down: Predators control the population of herbivores.     * Bottom-up: Resource availability (plants) controls higher levels.
• Green World Hypothesis: The world is green because predators keep herbivores in check, preventing them from consuming all the vegetation.
• Mesopredator Release: When a top predator is removed (e.g., wolves), mid-sized predators (e.g., coyotes) increase in abundance, which can lead to the decline of smaller prey.
• Trophic Cascade: An ecological phenomenon triggered by the addition or removal of top predators, which propagates through the food web (e.g., Sea Otters keeping Sea Urchins in check to protect Kelp forests).
• Ecology of Fear: The behavioral changes in prey induced by the presence of predators (e.g., elk avoiding certain grazing areas when wolves are present).

Population Dynamics

• Population: A group of individuals of the same species in a specific area.
• Dynamics: The study of how populations change in size and composition over time.
• Models:     * Exponential Growth: J-shaped curve. Characterized by the equation: $\frac{dN}{dt} = rN$.     * Logistic Growth: S-shaped curve. Includes a carrying capacity ($K$). Equation: $\frac{dN}{dt} = rN \left(1 - \frac{N}{K}\right)$.
• Density-Dependence: Factors (like food or disease) whose impact changes based on the population density.

Ecosystem Services

• Definition: The benefits humans obtain from ecosystems.
• Four Categories (Millennium Ecosystem Assessment):     1. Provisioning: Products (food, water, lumber).     2. Regulating: Control of climate, water purification, pollination.     3. Supporting: Soil formation, nutrient cycling.     4. Cultural: Recreational, spiritual, aesthetic.
• Equity: Socioeconomic status often determines access to these services; lower-income groups are often more vulnerable to the loss of regulating services like clean water or flood protection.

Island Biogeography and Biodiversity

• Theory of Island Biogeography: Species richness on an island is determined by the balance between immigration and extinction.     * Large islands near the mainland have the highest richness.     * Small, distant islands have the lowest richness.
• Adaptive Radiation: The rapid diversification of a single ancestral line into many species filling different niches (e.g., Darwin's Finches or Cichlids in Sulawesi).
• Congener Replacement: The replacement of one species by another closely related species as one moves across a geographic gradient or between islands.

Desert Ecology

• Hadley Cells: Atmospheric circulation cells where air rises at the equator and sinks at approx $30^{\circ}$ North and South latitude, creating dry desert conditions.
• Adaptations:     * Behavioral: Nocturnality, burrowing.     * Physiological: Concentrated urine, metabolic water production.
• Chilean Woodstar: A hummingbird species whose decline illustrates how habitat fragmentation and loss of specific nectar sources in arid environments can lead to extinction risk.

Avian Biodiversity and Evolution

• Evolution: Birds are considered modern-day theropod dinosaurs.
• Molting: The process of replacing feathers.     * Complete Molt: All feathers replaced.     * Partial Molt: Only some feathers replaced.
• Beaks: Evolved into various shapes (probing, cracking, tearing) to exploit different food niches, reducing interspecific competition.

Stakeholder Event and Policy

• Regulatory Process: Decision-making involves weighing scientific data against economic impacts and social values.
• SSO Hearing: The debate surrounding the Sea Otter (SSO) centers on their role in ecosystem health (enhancing kelp) versus their impact on commercial fisheries (consuming shellfish resources).
• Decision-making: It is complex, often controversial, and involves significant tradeoffs between different stakeholders' interests.