RulesOfThumb

Please add the rules of thumb you find during your readings or in lecture. Maybe others can edit them or organize them. -JLB


 * Balance Between Colonization and Extinction (Differentiating Metapopulations from Island Biogeography)**


 * || Island Biogeoraphy || Metapopulations ||
 * What is being measured? || Species Richness (S); Species Diversity || Patch Occupancy (P); Population Persistence ||
 * How many species? || Many || One ||
 * Structure || Mainland connected to islands by immigration/colonization, dispersal || Metapopulation (subpopulations/patches/discrete habitats) connected by dispersal, leading to colonization of empty patches. ||
 * Equilibrium/Stabilization Depends on || * Immigration (or more accurately, colonization), and Extinction.
 * Island size- the larger the area the more resources, while smaller islands support small populations (more likely to go extinct).
 * Distance from the mainland. Species richness of the mainland. || * Stable when the rate at which colonization (via immigration) is equal to the rate of extinction.
 * Distance between patches determines patch colonization rate/occurrence (occurs when model assumption becomes violated).
 * Extinction rate may vary with patch size or general resource availability (occurs when model assumption becomes violated). ||

Competition & Predation (lessons from the L-V models)
Note: this is from a former student
 * || Competition || Predator-prey ||
 * || How do competing species coexist? || What stabilizes predator-prey dynamics? ||
 * self regulation || When intraspecific competition is stronger than interspecific competition. || Prey carrying capacity. Predator self regulation / carrying capacity ||
 * specialization || Different resource requirements or specializations can reduce the strength of interspecific interactions || When predators have alternate prey, their populations will be more stable. When they prey-switch this leads to a type III functional response and a "refuge" from predation at low prey densities. ||
 * spatial/temporal heterogeneity || (Slightly) different fundamental niches such as different environmental tolerances can lead to overall coexisitence, even though one might outcompete the other within a certain range or habitat. Similarly, avoidance in time (e.g., foraging at night to avoid the competitor) can reduce interspecific interactions || Prey refuges in space or time can stabilize. (Similar to type III functional response) ||
 * metapopulations || If the poor competitor is the superior disperser (a clear trade-off) then the two can coexist across a landscape. Similarly, if there is strong pre-emption, then the first one to arrive has the advantage and there can be coexistence across patches/habitats. || If the prey is a better disperser than the predator, this can lead to coexistence across patches/habitats/oranges. ||

" Everyone has setbacks. It's what you do to get over them that separates you from the success you're after." -Ryan (a friend of mine).
 * General rules of thumb:**

“There’s no secret cure for procrastination entirely; it’s a disease that solely you control for greater success and failure.” - Toliy


 * Physiological Ecology:** The study of how physiology impacts an organism's survival relative to others, in the context of the resources and environments that are available on the planet.
 * **Adaptation:** A trait that is the result of a genetic and/or phenotypic change across generations, that impacts fitness within a population.
 * **Acclimation:** A trait that is the result of an organism's ability to adjust to the environment in which it lives within a short period of time (days to weeks).


 * Biogeography**:
 * 1) **Alpha diversity**: Represents the local diversity; ie the number of species occupying a small, essentially homogenous area.
 * Determined by the regional diversity and local specie interactions
 * 1) **Gamma diversity**: Represents regional diversity; ie the number of species occupying a larger, more inclusive area, possibly a whole continent or ocean basin. (Think big!)
 * 2) **Beta diversity**: Represents the turn over rate for a species
 * Related to population size, smaller populations typically have a higher turn over rate.


 * **Allopatric speciation:** occurs when biological populations of the same species become isolated from one another. Over time these species undergo evolution seperately to produce a separate isolated species. Two events can lead to allopatric speciation:
 * **vicariance event:** occurs when a specific population is divided as a result of a geologic barrier (i.e. a mountain or body of water)
 * **founder event**: occurs when a new population is formed by a small group of individuals that migrated from a larger population. A founder event results in the loss of genetic variation.


 * Physiological Ecology:**


 * Potential Evapotranspiration (PET): The //potential// amount of water that could be evaporated or transpired** ** from an ecosystem if that amount of water were available. ** (Remember that Evapotranspiration= evaporation + transpiration)
 * **PET depends on temperature:** PET in mm of precipitation per month is two times the temperature in °C
 * Ex: Temp: 20*C then PET is 2(20°C) = 40mm
 * Actual evapotranspiration (AET) is equal potential evapotranspiration if there is ample water available. If water is limiting, then AET is equal to the amount of water available. So if the actual precipitation is 100mm but the PET is 40mm then AET will only be 40mm because it is the minimum amount. If actual precipitation was 20mm and PET was still 40mm then AET will be 20mm.

**Ecological Biogeography**
 * **Barriers to Dispersal:**
 * **1) Corridors**
 * Routes that all species can cross
 * Corridors tend to have similar environmental conditions to the patches they connect
 * (Can make use of corridors when mapping out a reserve)
 * **2) Filters**
 * Selectively prevent some species from crossing while allowing other species through
 * **3) Sweepstakes Routes**
 * Habitats that are nearly impossible to cross except during rare and unpredictable circumstances
 * Can be crossed by **Jump Dispersal, Diffusion, and Secular Migration**


 * Climate Change**
 * **Detection:** These are climate studies that focus on demonstrating a statistical change in the climate system
 * **Attribution:** This is process of determining the probable cause or probable causes of a certain observed phenomenon. These are climate studies that focus on establishing which factors are the most likely causes for detected changes
 * **Feedbacks:**
 * **Positive -** the process involved is amplified or accelerated by the product or output of that specific process
 * **Example:** Exponential population growth - as a population grows, it produces more individuals which will then allow for the population to grow faster
 * **Negative -** the process involved is slowed or stabilized by the product or output of that specific process
 * **Example:** Predator-prey systems - there is an increase in the abundance of the prey populations which will produce more food for the predator. This will then lead to an increase in the predator populations. However, an increase in predator populations will subsequently lead to a decrease in the prey populations
 * Rare events matter when looking at life cycles and population increase.