Realm: Marine
Climate: Temperate
Biome: Temperate Shelf and seas ecoregions
Central latitude: 25.216667
Central longitude: -80.216667
Duration: 2 years, from 1975 to 1983

340 records

31 distinct species

Across the time series Agaricia agaricites is the most frequently occurring species

Methods

The determination of coral species coverage and abundance was carried out using a grid of line transects (Loya 1972, 1978). The positions of the transects were established by stretching a taut line from the seaward base of the reef at 21 m depth to the shoreward side of the reef fiat, a horizontal distance of approximately 300 m. The line was run on a compass heading of 110-290 degrees magnetic. This course was along the axis of surge channels in the Acropora palmata zone and normal to the direction of incoming swells as determined by the orientation of the seafan, Gorgonia ventalina, which orients perpendicularly to the swell direction (Wainwright and Dillon 1969). A second line was placed parallel and 25 m to the north of the first. Numbered stainless steel pins (15 x 0.95 cm) were driven into the reef along the two lines to create a series of transects on the reef that resembled the rungs of a ladder. Twenty-one 25 m long "rungs" were positioned on the reef between its base and reef flat. Twenty-five meters was chosen as the optimal transect length as an asymptotic cumulative number of species had been reached in trials within 20 m in accordance to the methods first described for reefs by Loya (1972). The careful alignment of the transects insured that we would survey the reef zones and coral abundance relative to their natural orientation as determined by the incoming wave surge and depth (Goreau 1959). The horizontal spacing between the transects varied from 3 to 20 m depending on the density of coral coverage and the degree to which the depth of the reef substrate was changing. Spacing was close at the base of the reef where coral coverage was high and the slope steep. Line spacing of 20 m was used in the relatively homogeneous, gently sloping regions of the reef (see Fig. 3 for reef profile and transect location). Carysfort Reef was surveyed in 1975 (Dustan 1985) and resurveyed in the summers of 1982 and 1983; it took two field sessions to find and resample all the transects. Transects 1-10 were surveyed in 1982 and 11- 21 in 1983. The majority of the original pins marking the transects were located (33 of 42), which enabled us to remeasure the identical reef coral populations initially surveyed in 1975. We could not find transect pins for two transects on the reef flat, one transect in the Acropora palmata zone (the large coral colonies holding the pins had been physically destroyed), and the pins marking one end of transects 21 (back reef), transects 6 and 7 (fore reef). On the reef flat, and on transects 6 and 7, we found the tag lines we had used in 1975 to find the pins but the pins had been removed. Whenever we could not find the original pin we remeasured the distances from existing pins and reset the end positions of the transects. Thus the transects in these regions were not precisely on top of the previously surveyed corals but were less than a meter from their original positions. The measurement of a transect began by securing the end of a length of floating polypropylene line to a transect pin. The line was then strung through the eye of the corresponding pin at the other end of the transect and pulled taut down onto the reef substrate. The line was inspected to be sure that it was strung straight between the two pins thus overlying the same portion of reef as in 1975. The length of line crossing over coral colonies and the space between them was measured to the nearest 0.5 cm with a ruler and tallied on a plastic slate. Branching species were measured from the edges ofa colony's branch tips. When branching colonies occurred in thickets, branches that could be traced to a common origin were considered to be part of a single colony. Colonies were inspected for algal infections, physically damged areas, sediment covered tissue, or any other type of blemish. Regions of the reef that showed large scale destruction were examined for debris to ascertain the cause of the damage. The data were transferred to a notebook.

Citation(s)

@Article{BioTIME_cit427, Study_id = {695}, Citation_id = {427}, Author = {Dustan, Phillip and Halas, John C.}, Journal = {Coral Reefs}, Pages = {91-106}, Title = {Changes in the reef-coral community of Carysfort reef, Key Largo, Florida: 1974 to 1982}, Volume = {6}, Year = {1987}, Doi = {10.1007/BF00301378}, Language = {English} }