Conservation Biology Overview

Class time starts at 10:10.
The final quiz will take place next week, mostly covering today's lecture content.
Peer reviews for rough drafts are due Friday. Ensure you know which paper to review—resources are available for guidance.
Tutorials for writing support have ended; however, TAs are available during office hours for assistance.

The final quiz may include conceptual questions from the slides presented in the class.
Class will continue with lectures wrapping up the content of the semester focusing on significant concepts.

Definition: Unequal sex ratios can lead to smaller effective population sizes (NE).
Drivers of Unequal Sex Ratios:
- Temperature-Dependent Sex Determination: Certain reptiles and fish have their sex determined by the incubation temperature of their eggs, with warmer temperatures often resulting in more females.
- Human Impact: Hunting practices that target only males can drastically affect sex ratios.
- Demographic Stochasticity: Random events can lead to sex ratio imbalances in small populations.

Snapping Turtle: Males born around 26 degrees Celsius, females at either cooler or hotter temperatures.
Map Turtle: Higher female ratios at warmer incubation temperatures.
Alligator: Similar pattern to snapping turtles, with temperature influencing the sex ratio.

Equation: NE can be calculated using the formula: $NE = \frac{4(N<em>m N</em>f)}{(N<em>m + N</em>f)}$ Where:
- $N_m$ = number of breeding males
- $N_f$ = number of breeding females
Example: If a population has significantly more females than males due to hunting, this can reduce the overall genetic health and viability of the population.

A cycle that small populations can enter:
- Start with reduced populations leading to increased effects of genetic drift and inbreeding.
- Loss of genetic diversity decreases adaptability and increases mortality rates.
- Can ultimately result in extinction if not addressed.

Definition: The smallest isolated population having a high likelihood (typically 99%) of surviving for a certain number of years.
Factors Influencing MVP: Habitat needs, genetic diversity, reproductive rates, and environmental conditions.
Estimates: Generally inferred from historical data and can vary widely between species.

A method used to estimate the persistence of species over time.
Factors in demographic and environmental stochasticity to create models for population trends.
Components Needed: Current population size and estimates of population change (births, deaths, migrations).

In Situ: Conservation of species in their natural habitats, focusing on ecosystem preservation.
Ex Situ: Conservation efforts like captive breeding, where individuals are removed from their habitats for protection.

In Situ:
- Benefits: Conserves entire ecosystems and promotes natural preadaptations.
- Costs: Takes time and may not be sufficient for critically endangered species.
Ex Situ:
- Benefits: Allows for controlled breeding and protection from threats.
- Costs: Can lead to a loss of natural instincts and adaptations.

Reintroduction: Releasing animals bred in captivity or taken from the wild to restore populations.
Reinforcement: Introducing individuals into an existing wild population to increase genetic diversity.
Examples of Successful Programs:
- California Condor: Population numbers increased after a captive breeding program turned around the decline.
- Golden Lion Tamarin: Successful captive breeding and reestablishment into fragmented habitats.
- Gray Wolf in Yellowstone: A controversial reintroduction led to ecological changes and community conflict.

Emphasize the importance of diverse conservation strategies and continuous research to ensure effective population management.
Collaboration and innovative approaches are necessary to tackle conservation challenges.