Status: 

Ongoing

Title

LFDP phenology plot seedlings – 16 ha plot
Summary

Short name: 

LUQMetadata175

Data set ID: 

175

Abstract: 

These data on temporal and spatial patterns of seedling recruitment in conjunction with data on flower and seed rain production allow tests of hypotheses concerning causes of inter-annual variation and roles of different mechanisms in facilitating species coexistence. The data are being used to, among other things 1) quantify seasonal and inter-annual variation in reproductive output in tropical plant populations and communities; 2) analyze relationships between reproduction and a variety of hypothesized local and regional climate drivers; 3) evaluate evidence for long-term directional trends which could reflect responses to anthropogenic global change; 4) quantify spatiotemporal variation in seed arrival and seedling recruitment of individual species; 5) analyze associated evidence of recruitment limitation, life history trade-offs, density dependent recruitment and regeneration niche partitioning; and 6) evaluate how these processes interact with inter-annual variation in climate and plant reproduction.

Dates
Date Range: 
2007-03-22 00:00:00 to 2015-04-27 00:00:00
People

Additional Project roles: 

Name: Eda Melendez-Colom Role: Data Manager
Name: Christopher Nytch Role: Associated Researcher
Methodology

Methods: 

We census seedlings once each year, in 360 1 m2 subplots. Three subplots are grouped together around each of 120 seed traps in the LFDP. Seed traps are located at 8 m intervals along pre-existing trails and 8 m from on either side of the trail. The three seedling subplots are located 2 m from each seed trap at polar coordinates chosen in a stratified random manner (i.e., between 1-120 degrees, 121-240, and 241-360) but rejecting locations that fell in pre-existing trails.

Data are recorded during the annual dry season from January to April. Plot substrate (leaves, bare soil, rock, herbs, dead wood, live wood), is assessed for each plot, with percent coverages estimated to the nearest 5% and totaling 100%. The number of grasses and Heliconia sp. culms are also counted in each plot, and the height of the tallest grass and all Heliconia culms is measured from the ground to the tip of the blade/tallest leaf. A densiometer is used to take measurements of canopy cover directly above the center of each seedling plot. General gap size is assessed by looking up at the tree canopy overhead and recording whether seedlings see a large (many large tree crowns missing), medium (several large tree crowns missing), small (one large tree crown missing), or no gap.

In each plot, all woody-stemmed (lianas included) new recruits and surviving seedlings >0 cm (i.e., there is no lower size threshold) and less than 1 cm diameter at 130 cm height are identified to species (using a six letter code, and marked with permanent, uniquely numbered tags. Seedlings for which species cannot be determined are labeled as “Unknown.” The predominant substrate on which that the seedling is growing is noted. Seedling height (excepting palms) is measured from the ground (or root collar or seed if that is visible) along the length of the stem to the apical meristem. For all seedlings >= 10 cm in height, the diameter is measured at the widest axis of the base of the stem. For stems >=130 cm in height, the diameter at 130 cm is also recorded. For plants with multiple stems, height is measured only for the tallest stem. The location of each seedling is mapped relative to other seedlings and the plot boundaries. Old tags found on the ground or on dead stems are removed from the plot, and tags that cannot be located are recorded as “Not Found.” We continue to follow seedlings that grow to exceed 1 cm diameter at a height >=130 cm.

 For palms, seedling height is measured as the distance from the ground to the tip of the tallest/longest leaf. Stem height of palms is recorded from the ground to the top of the stem between the last pair of leaf scars, below where the oldest frond is attached. Diameter of palms is measured at the widest part of the base. When the palm has an obvious woody stem that is clear of dead fronds, a second diameter measurement at the top of the stem, or at 1.3 m, whichever is lower.

For woody* vines rooted in the plot height is measured as the length from the ground along the vine to the apical meristem (or the highest point that can be measured) or the point where the vine leaves the plot. If the height/length of the vine is >=1.3 m (within the plot), the diameter is also measured at 1.3 m.

 Comments are recorded indicating if a seedling stem is broken or has died back, if there is evidence of herbivory or lack of leaves altogether, and tag numbers of large trees with census tags that are located within the seedling plot.

Seedling identifications have been made by Maria Aponte (2007-2008), John Bithorn (2007-2010), Christopher Nytch (2010-2011), and Alejandro Miró Co (2011), in addition to volunteers who have learned some of the identification characteristics well. This FDP is described in greater detail at http://luq.lternet.edu/research/luquillo-forest-dynamics-plot-lfdp.

* One herbaceous vine, Dioscorea polygonoides, is included in the dataset as well.

Additional information: 

ADDITIONAL NOTES:

  • Values of the variable SPECIES include the six-letter code “UNKSPP” for unknown species. Accompanying notes in the COMMENTS columns may indicate a partial identification to levels above species. Examples include, “VINE1” for unknown lianas, “MYRSPP” for the genus Myrcia, and “RUBIACEAE SP” for plants in the Rubiaceae family.
  • Records marked as ‘Q’ or ‘R’ for the variables ‘FINAL STATUS’ and ‘A/D/N/NF/Q/R’ are kept in the dataset for bookkeeping purposes and should not be used for any analyses.

  • Values for LEAVES, BARE SOIL, ROCK, HERBS, LIVE WOOD and DEAD WOOD for each 1 m2 in any given year XXXX are determined by considering the percent cover of each variable in a 3-dimensional volume between 0-10 cm above the ground.

  • Values for LEAVES, BARE SOIL, ROCK, HERBS, LIVE WOOD and DEAD WOOD in any given year are estimated to the nearest 5% and always sum to 100%.

  • The variable LEAVES includes large palm fronds and other fine organic matter (e.g., a mat of tiny rootlet threads).

  • The total percent cover of grasses and herbs per subplot is summed together with other herbaceous plants and listed in the HERB column.

  • The variable DEAD WOOD includes both standing dead stems and fallen woody debris.

  • The variable LIVE WOOD includes standing live saplings or trees, prone stems and woody vines that are rooted in and/or run through the plot.

  • Non-blank values for the variable HEIGHT GRASS are always associated with a value for the variable NUM. GRASS that is >0.

  • Non-blank values for the variable HEIGHT HELCAR are always associated with a value for the variable NUM. HELCAR that is >0.

Status: 

Ongoing

Time Period: 

Long-Term