Luquillo Data Sets By Insertion Order

Transects are conducted to note the vertical distribution and relative abundance of anole species. Data permit the calculation of average sighting distance for each species which is used in the final calculation of abundance.

Transects 60 m long are conducted at alternate points in the 9 ha grid at El Verde. Transects 80 m long are conducted at alternate points at the Bisley Grid in watersheds #1 and #2. Data are used to support the GIS database.

The survey of gaps at El Verde covers about 35 ha, including the 9 ha grid. We defined a treefall gap at El Verde as a hole in the forest canopy extending down to an average height of about 3 m or less above ground. The edge of a gap was delineated by the vertical projection of the edge of the canopy foliage. We measured the dimensions of all gaps present in the 35-ha study site in August 1989, one month before Hurricane Hugo. For each gap we measured L, the longest axis of the gap (distance between edges), and W, the longest axis perpendicular to L, and then approximated gap area as that of an ellipse: Area = p LW/4 (Runkle 1992). Only openings ³ 20 m2; were counted as gaps.

The purpose of this study is to document the recovery of vegetation on new landslides in the Luquillo Experimental Forest, in particular seedlings <1m tall.

Daily emperature has been measured at the El Verde Field Station since 1975 (see methods). Monthly averages have been calculated. Lowest average values for minimum temperature were recorded from January to April with nearly 18 Centigrades during this period of time (see chart). During these months, the lowest average minimum temperature was recorded in 1976 ranging from 20 to 22 Centigrades (see chart). Highest minimum montly average records are shown from June to October with peak in the vecinity of 20 Centigrades. The year with lowest minimum tempearture was 1995 and 2000 with the low values near 14 and 15 Centigrades, respectively.

Stream water is collected weekly at the Luquillo Mountain sites listed below. These data sets begin as early as 1983; LTER sampling began in 1988.

Stream water samples are grab samples taken from the water/air interface at stream channel center on the sampling day (usually Tuesdays). A continuous record of stream stage (height) is recorded by a datalogger at all ongoing stream sampling sites. Average daily streamflows are available from the USGS and at other locations (Hydrology and Meteorology) on this site.

All samples are measured for pH and conductivity, and then filtered (pre-combusted Whatman GF/F glass fiber filter) prior to further analysis. From 1983-1994 samples were cooled and returned to the San Juan chemistry laboratory for analysis. During those years, samples for NH4 and NO3 analyses were refrigerated continuously until analysis. Subsamples for NH4 analysis were also preserved with 1 molar H2SO4. From 1994 on, samples for NH4 and NO3were frozen until analysis, were not acidified, and all analyses were conducted at the University of New Hampshire.

Stream water Sampling Sites
Descriptions of LTER LUQ stream water weekly sample chemistry data from 1988 onwards. Chemical concentrations are recorded as mg/L or mg/L as appropriate. Values below detection limits are recorded as 1/2 the detection limit. 

While doing the survey of gaps at El Verde the number and height of Cecropia saplings found in gaps where recorded. Since this species is mostly restricted to gaps, an estimate of the total population of Cecropia in the regeneration size classes in the forest can be obtained. (There are others along the edges of the Sonadora and Prieta.) The abundance, dispersion, and size class distribution of the Cecropia population is an index of disturbance in tabonuco forest and make an interesting study in its own right.

The stomach contents of 10 adult individuals of each of three anole species (Anolis gundlachi, A. evermanni, and A. stratulus) were collected to determine the number, type, and volume of prey consumed following Hurricane Hugo. Gut contents were identified to the lowest taxon possible and were measured.

Data set includes all available daily, weekly, and monthly rainfall from several climate stations in the northeast section of the Luquillo Experimental Forest. These stations are surround the Bisley Experimental watersheds and the Sabana Field Station are are operated by the USFS and the USGS. Weekly canopy throughfall is also collected weekly from the Bisley experimental watersheds.