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5: Populations

  • Page ID
    31604
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    Chapter Hook

    Roadkill, we’ve all seen it on the roadside. It is just one very unfortunate outcomes of our extensive road networks. Roads, especially freeways and busy highways, also break apart habitats. When habitats are broken up into smaller pieces it weakens wildlife populations which need to move freely across landscapes for resources, refuge, and mates. Over long time scales, these fragmented habitats decrease species diversity, weaken species population gene pools, and can lead to extirpation (elimination of local population(s)) and extinction. As a result of numerous studies, ecologists have found one solution, wildlife crossings (aka green corridors or wildlife corridors). Wildlife crossings look like an underpass or overpass. However, they are filled with dirt and plants to look more natural. These crossings enable wildlife populations to move more freely, and safely, across landscapes all over the globe.

    Wildlife overpass over Singapore highway
    Figure \(\PageIndex{a}\): A newly constructed wildlife overpass over a Singapore highway. Image by Benjamin P. Y-H. Lee (licensed under CC-BY-4.0)

    Populations are interacting and interbreeding groups of individuals from the same species in a common area. The study of population ecology focuses on population size and the factors that regulate population growth.

    Attribution

    Rachel Schleiger and Melissa Ha (CC-BY-NC)

    • 5.1: Population Dispersion
      Individuals in a population may be dispersed in a clumped, random, or uniform pattern.
    • 5.2: Population Size
      Population size is the number of individuals in a population, and population density is the number of individuals per unit area. Quadrat and mark and recapture techniques can estimate population size.
    • 5.3: Population Growth and Regulation
      Population ecologists make use of a variety of methods to model population dynamics. An accurate model should be able to describe the changes occurring in a population and predict future changes.
    • 5.4: Life History
      There are two main reproductive strategies, but most species fall somewhere in between them. K-selected species have long lifespans, high parental care, and few offspring. r-selected species have short lifespans, low parental care, and many offspring. Life tables organize life history information. Survivorship curves illustrate the relationship between mortality and age.
    • 5.5: Data Dive- Wildlife Corridors
    • 5.6: Review


    This page titled 5: Populations is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Melissa Ha and Rachel Schleiger (ASCCC Open Educational Resources Initiative) .

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