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Bhopal Birds - Avian terms Category: Animals and Nature > Avian Terms Date & country: 27/09/2013, USA Words: 231

Species diversity
see Diversity.

Species richness
the number of species in a given area (Ralph 1981578).

Species-area relationship
a plot (often log-log) of the numbers of species of a particular taxon against area, such as islands or other biogeographic regions (Brown and Gibson 1983570).

Spot-mapping method
a census procedure that plots on a map individuals seen or heard in a surveyed area. The survey is usually conducted over a period of days or weeks in a season, and individual territories or home ranges are then demarcated by examining the clusters of observations. Used in Breeding Bird Census (Ralph 1981578) (syn. Territory-mapping).

Stable age distribution
the proportions of the population in different age classes when the rate of increase has converged to a constant (which depends on the fixed schedules of survival and fecundity). The ratios between the numbers in the age classes are constants (Caughley 197789).

Statistical bias
a difference between the expected value of an estimator and the population parameter being estimated (Gilbert 198712) (cf Measurement bias).

Stenotopic
found in only one or a relatively small number of habitats (MacArthur and Wilson 1967191).

Stochastic
implies the presence of a random variable (Marriott 1990197).

Stressor
any chemical, physical, or biological entity that can induce adverse effects on individuals, populations, communities, or ecosystems (Risk Assessment Forum 19921).

Strip transect method
a procedure using a strip of land, or water, of fixed direction that is sampled visually and/or aurally by an observer. Counts may be one of the following fixed distance (width) counts limited to a strip of set width for all or specially chosen species; variable distance (width) counts, with different, species-specific widths that are determined to reflect detection attenuation; or unlimited distance counts, in which all detections are recorded regardless of distance (Ralph 1981578) (syn. belt-transect).

Subclimax
a stage of succession along a sere prevented from progressing to the climatic climax (i.e., the steady-state community characteristic of a particular climate) by fire, grazing, and similar factors (Ricklefs 1979880).

Subspecies
subpopulations within a species that are distinguishable by morphological characteristics and, sometimes, by physiological or behavioral characteristics (Ricklefs 1979880) (syn. race).

Succession
replacement of populations in a habitat through a regular progression to a stable state (climax) (Ricklefs 1979880).

Survey
an enumeration or index of the number of individuals in an area from which inferences about the population can be made (Ralph 1981578) (cf Census, Count).

Survival
the proportion of newborn individuals alive at a given age (Ricklefs 1979880).

Sympatric
occurring in the same place, usually referring to areas of overlap in species distributions (Ricklefs 1979880).

Syntopic
pertaining to populations or species that occupy the same macrohabitat (Lincoln et al. 1982242).

Territory
any area defended by one or more individuals against intrusion by others of the same or different species (Ricklefs 1979881) (cf Home range).

Territory-mapping
see Spot-mapping method.

Third-year (TY) bird
a bird in its third calendar year of life (Pyle et al. 198727).

Transect
a cross section of an area along which the observer moves in a given direction (Ralph 1981578) (see Line transect, Point transect, Strip transect method).

Trophic
pertaining to food or nutrition (Ricklefs 1979881).

Trophic level
the position in the food chain determined by the number of energy-transfer steps to that level (Ricklefs 1979881).

Trophic structure
organization of the community based on feeding relationships of populations (Ricklefs 1979881).

Turnover
the process of local extinction (e.g., on islands) of some species and their replacement by other species. The turnover rate is the number of species eliminated and replaced per unit time (MacArthur and Wilson 1967191).

Ultimate factors
aspects of the environment that are directly important to the well-being of an organism (for example, food) (Ricklefs 1979881). Ultimate factors are concerned with fitness (Lack 19545) (cf Proximate factors).

Variable circular plot
see Point count method.

Variable-distance method
see Strip transect method, Point count method.

Variance
a statistical measure of the dispersion of a set of values about its mean (Ricklefs 1979881).

Winter Bird Population Study (U.S.)
a program of the National Audubon Society involving census of wintering birds by counting and mapping, but not depending on persisting occupation of territories or home ranges (Ralph 1981578) (cf Breeding Bird Census).

Xeric
referring to habitats in which plant production is limited by lack of water (Ricklefs 1979882). - See more at http//www.bhopalbirds.com/page/Avion%20Terms#.UkXMsT9rPgZ