## The Floristic Composition and Community Structure of the Forest Park Woodland, Queens County, New York

## Glossary

- Allelopathic
- Of or relating to allelopathy, the suppression of growth in one plant species due to chemicals produced by another.
- Approximate Randomization Analysis
- A randomization test involves the comparison of an observed test statistic with a distribution that is generated by randomly reordering the data values in some sense.
- Bootstrapping
- The essence of bootstrapping is that in the absence of any other information about a population, the values in a random sample are the best guide to the distribution, and that re-sampling the sample is the best guide to what can be expected from re-sampling the population. Much of the research on bootstrapping has been aimed at developing reliable methods for constructing confidence limits for population parameters (see Manly, 1997).
- Climax species
- The plant species that inhabit an area that has undergone the final stage of vegetational succession.
- Confidence interval
- The interval within which a parameter of a parent population is calculated (on the basis of the sampled data) in order to determine a stated probability of lying. The larger the sample size (n), the smaller the confidence interval and the more accurate the estimate of the parent mean.
- Confidence limits
- The upper and lower boundaries of the confidence interval.
- Descriptive statistics
- The general statistics of individual organisms or population (e.g. mean tree diameter or height).
- Diameter at breast height (DBH)
- The outside-bark diameter of a tree measured at 4.5 feet (1.37 meters) above the forest floor on the uphill side of the tree.
- Frequency distribution
- A set of frequencies or probabilities assigned to a set of events.
- Gap-phase regeneration
- The pioneer phase during which trees begin to colonize a site.
- Importance value (IV)
- An abundance estimate consisting of the sum of three relative values: relative density (the number of a given species/family expressed as a percentage of all species present), relative frequency (the frequency of a given species/family expressed as a percentage of the sum of frequency values for all species present), and relative dominance (the basal area of a given species expressed as a percentage of the total basal area of all species present (Oxford Dictionary of Ecology).
- Knob-and-kettle topography
- Also known as "sag and swell" topography, this is a landscape type sometimes associated with recent terminal moraine (debris and deposits laid down at the edge of a glacier). It consists of hummocky mounds (knobs) alternating with depressions (kettles).
- Pioneer species
- A species that is adapted to the early stages of vegetational succession.
- Point estimate
- The estimation of a parameter of a parent population as a single value. An arithmetic mean, such as mean density, is a single number called point estimate in statistics and must always be accompanied by some information upon which its usefulness as an estimate can be judged.
- Quartiles
- The value of a variable below which three quarters (1st or upper quartile) or one quarter (the 3rd or lower quartile) of a distribution lie. The median is the 2nd quartile.
- Regression analysis (simple and multiple linear regression)
- Simple linear regression and multiple linear regression are related statistical methods for modeling the relationship between two or more random variables using a linear equation. Simple linear regression refers to a regression on two variables while multiple regression refers to a regression on more than two variables. Linear regression assumes the best estimate of the response is a linear function of some parameters (though not necessarily linear on the predictors). See http://en.wikipedia.org/wiki/Regression_analysis.
- Shannon-Wiener index (H')
- One of several indices used to measure biodiversity. It takes into account the species evenness (relative abundance) of a population or community as well as the special richness (total number). For more information, visit http://en.wikipedia.org/wiki/Shannon-Wiener_Index.
- Simpson's index
- A simple mathematical measure of diversity in a community, devised by E.H. Simpson in 1949. See http://www.tiem.utk.edu/~gross/bioed/bealsmodules/simpsonDI.html.
- Species richness
- The total number of different species present.
- Singleton
- Occurring singly.
- X, Y coordinates
- The most common tools for identifying points in space are the Cartesian coordinates. The x-axis is the abscissa and y-axis is the ordinate. During vegetation surveys, Cartesian coordinates display the spatiality of individuals across a study plot and reveal the basic patterns of distribution—random, regular, and clumped.