Mark-recapture

Definition

Mark-recapture is a method used in ecology to estimate the size of animal populations by capturing a number of individuals, marking them, and then releasing them back into their environment. After a set period, researchers capture another sample of individuals to see how many are marked, allowing for population estimates based on the proportion of marked to unmarked individuals. This technique is crucial for understanding population dynamics and making informed conservation decisions.

5 Must Know Facts For Your Next Test

1. The mark-recapture method relies on the assumption that marked individuals mix evenly with unmarked individuals after being released.
2. A common formula used in mark-recapture studies is the Lincoln-Petersen index, which estimates population size as $$N = \frac{(M \times C)}{R}$$, where N is the estimated population size, M is the number of marked individuals in the first sample, C is the total number captured in the second sample, and R is the number of recaptured marked individuals.
3. This technique is valuable for studying mobile species where traditional census methods may be impractical.
4. Mark-recapture studies can provide insights into population trends over time, helping researchers understand factors affecting survival and reproduction.
5. Ethical considerations must be taken into account, ensuring that marking does not significantly harm the animals or alter their behavior.

Review Questions

• How does the mark-recapture method help estimate population sizes in wildlife studies?
  • The mark-recapture method helps estimate population sizes by allowing researchers to capture and mark a sample of individuals from a population. After releasing these marked individuals back into their environment, researchers can later capture another sample and count how many of these are marked. By using the proportion of marked individuals in this second sample, researchers can apply formulas like the Lincoln-Petersen index to estimate the total population size based on known values from both samples.
• Discuss the assumptions underlying the mark-recapture method and their implications for data accuracy.
  • Key assumptions of the mark-recapture method include that marked individuals have an equal chance of being recaptured as unmarked ones, that marks do not affect survival or behavior, and that there are no significant changes in population size between captures. If these assumptions are violated, it can lead to inaccurate population estimates. Researchers must carefully design their studies and consider factors such as marking methods and time intervals between captures to minimize biases and improve data reliability.
• Evaluate the role of mark-recapture studies in conservation efforts and provide examples of their application.
  • Mark-recapture studies play a crucial role in conservation by providing reliable estimates of endangered species populations, helping inform management strategies and conservation priorities. For instance, they have been used to monitor sea turtle populations to assess recovery efforts after nesting site protections were implemented. Additionally, these studies enable scientists to track population dynamics over time, revealing trends that can guide habitat preservation and restoration efforts necessary for sustaining biodiversity and ecosystem health.

Related terms

Population Size: The total number of individuals within a specific population at a given time.

Sampling Techniques: Various methods used to select individuals from a population for study, including random sampling and systematic sampling.

Demographic Parameters: Quantifiable characteristics of populations, such as birth rates, death rates, and age distribution, that help in understanding population structure.