A DATA SET is a series of observations collected by the same methodology. Each data set should have documentation sufficient for someone unfamiliar with the research to replicate the study. Data sets may be broken into subsets (data files) that are discrete in space and time, in that order. The documentation for a data set should include all spatial and temporal subdivisions of the data.
(Data, Abstract, Methods, Variables)
NOTES:
| D. Jean Lodge | dlodge@lternet.edu |
DATA SET IDENTIFIER: MRCE/LTER Soil and Microbial Biomass Nitrogen
PROJECT TITLE: Nutrient Cycling in Tabonuco Forest (MRCE/LTER Litterfall Nutrient Fluxes, and Extractable Soil versus Microbial Biomass Nitrogen)
PROJECT DESCRIPTION: Understanding the long-term impact of deforestation on ecosystem structure and function of tropical forests may aid in designing future conservation programs to preserve biodiversity and sustain ecosystem productivity. We examined forest structure, tree species composition, litterfall (fine and coarse) due to Hurricane Hugo and subsequent fine annual litterfall inputs, litterfall rate, and leaf litter decomposition. The experiment was initiated by the MRCE (Minortity Research Centers of Excellence) program, and continued by the LTER. In addition to measuring nutrient fluxes from litterfall and decomposition, we measured KCl-extractable soil nitrogen in ammonium and nitrate forms to determine the effects of complete fertilization and removal of hurricane debris.
History of litterfall, decomposition and soil nitrogen availability studies (MRCE experiment) at the Luquillo Experimental Forest (LEF):
The Minority Research Centers of Excellence (MRCE) experiment was designed originally to determine whether forest productivity was limited by nutrient availability, genetic constraints or climatic variables along a steep environmental gradient in the Luquillo Mountains of Puerto Rico. Comparisons were made between dwarf forest at 500 m elev. and tabonuco forest from 300-400 m elev. There were two main experiments in the original design: 1) forest fertilization (complete versus none); 2) transplant experiments using common gardens at high and low elevation, with and without wind protection at high elevation. In addition, phenology of leaves was studied in the dwarf forest to determine the longevity of leaves in the canopy.
Hurricane Hugo struck in September 1989, following a year of pre-treatment measurements and just as the forest plot fertilization experiments were to begin, and deposited a year and a half of annual above ground litter inputs of phosphorus on the forest floor in green leaf litter (Lodge et al. 1991). As phosphorus is thought to be the most limiting element, this necessitated the addition of a hurricane debris-removal treatment as a second type of control in the lower elevation tabonuco forest. Furthermore, the hurricane changed the nature of the study into one of looking at changes in forest composition and the recovery of forest productivity in response to fertilization and hurricane debris-removal. Seedling, sapling, herbaceous plant, and fern responses, as well as measurements of light availability and canopy closure were added to the originally planned measurements of tree diameter growth, leaf litter production, and fine root production and turnover. Funding for continued studies of the MRCE plots ended in 1998, but they were of such great value as a long-term experiment that they were incorporated into the LTER program. Another hurricane in 1998 (Hurricane Georges) presented an opportunity to look at the effects of removing only the woody debris (in new plots) versus removing all hurricane debris.
The leaf decomposition experiment was originally designed to examine short-term disappearance of foliage from three important montane species: Prestoea montana (R. Grah.) Nichols, Dacryodes excelsa (Vahl.), and Cyrilla racemiflora. Hurricane Hugo (August, 1989) provided a unique opportunity to study effects of this type of natural disturbance on decomposition. The study was repeated in 1990 as part of the LTER, with some changes in the design that allowed for comparisons of short -term foliar litter biomass and nitrogen dynamics: (1) among the three species, (between the colorado and tabonuco forest types, (3) between riparian and upland sites, and (4) between pre- and post-hurricane environments.
LTER CORE AREAS: (See online list)| organic matter accumulation |
| primary production |
LEF LTER 1 RESEARCH TOPIC (Annotate all that apply) (See online list):
| Recovery-Nut. Storag |
We define a data file as a component
of a data set. A data set can have only one data file or more. Basically,
different data files have different data structures or format.
DATA
SET FILES (SUBSETS):
1 |
Soil samples for extractable N & bulk density May 1990 |
7 May 1990 |
once |
7 May 1990 |
|
2 |
Soil samples for extractable N & microbial N September 1990 |
15 September 1990 |
once |
15 September 1990 |
RESEARCH LOCATION: El Verde research area; Pico del Este research area
D.J. Lodge |
J. Zimmerman |
|
| X. Zou | |
| L. Walker | lwalker@lternet.edu |
| S. Guzman | |
J. Parrotta |
|
C. Asbury (deceased) |
|
B. Haines (deceased) |
D. Jean Lodge |
787-889-7445 |
SOURCE OF FUNDING (SPONSOR): US National Science Foundation, Minority Research Centers of Excellence (MRCE)
DATA SET ABSTRACT: The data reported here are only for tabonuco forest at El Verde. Following plot setup and one year of pre-treatment measurements, Hurricane Hugo struck before the first planned fertilization. Because a year and a half of annual above ground litter inputs of phosphorus were dropped onto the forest floor in the form of leaf litter, we added a debris removal treatment to the original two, fertilized & control.
These data were used to determine the pools of readily available nitrogen in soil solution in debris removal and fertilizer treatments applied to tabonuco forest at El Verde immediately after Hurricane Hugo struck in September 1989. The treatments (complete removal of litter and woody debris, total fertilization, and control). Both ammonium and nitrate were low in the May 1990 samples. All samples had more KCl extractable ammonium in September, but negligible nitrate. Increases in ammonium were greatest in the fertilized and debris removal plots as compared to the control treatment. These results were positively correlated with litterfall production and canopy closure, with faster rates of recovery in the fertilized and debris removal treatments as compared to the control. Soil extractable (readily available) N was negatively correlated with microbial N in the samples collected one year after Hurricane Hugo, indicating microbial immobilization of N. Century modeling results were consistent with our observations and indicated that woody debris increased the input of low-nutrient substrate to the soil thereby stimulating microbial uptake/immobilization. Thus the soil microbes in the control plots outcompeted the trees for limiting N, thereby slowing their recovery.
DATA SET METHODS: The following treatments were applied to plots established within replicate blocks of tabonuco forest at El Verde, PR within three weeks after a direct strike by Hurricane Hugo in September 1989: L (removal of all litter and woody debris); F (complete fertilization); and C (control). One control plot had a one-time accidental application of fertilizer between the two sample dates, so measurements were switched to a spare control plot in the same block in September - C(W). Treatments were applied to a 20x20 m area, and samples were taken from the core 10x10 m. See LTERDB111 for complete methods and map.There were 4 blocks established for this experiment, but one (Block III) was young and unlike the other three late-secondary forest blocks, so it was not included in analyses.
Samples were collected from each subplot and are reported by coordinates by DJL and by subplot numbers by others. DJL coded samples by Block (I, II and IV) and Plot (1-5) to compensate for dyslexia while others coded them as Block-Plot-Subplot numbers (e.g., 1-2-1 for Block II, Plot 1, Subplot 1).
Soil samples were collected volumetrically using a 8.5 cm diameter PCV tubes driven to 10 cm depth on 7 May 1990, and (567.5 cm3) ca. 15 September 1990. Entire soil samples were weighed and sieved through a 5 mm mesh screen, and mixed in a large inflated plastic bag. A 100 g subsample was taken and passed through a 2 mm mesh screen. Rocks sieved out were weighed and this weight was subtracted from the total. Roots were removed by hand. After removal of subsamples for KCl extractions, a ca. 20 g subsample was transferred to an aluminum pan, the wet weight recorded, then dried at 50C for at least one week, and the dry weight recorded.
Soil solution nitrogen was extracted from 2 replicate subsamples (ca. 4 g wet weight) in 100 ml 2N KCl within 24 h of collection. KCl suspensions were placed on a wrist-action shaker for 1 hour and then filtered with suction using Whatman #10 filter papers. Soil extracts were stored frozen until analyzed using a The samples collected in 15 September 1990 were intended for analysis of microbial N (fumigation-extraction method) as well as measuring the pool of extractable soil nitrate and ammonium in the control (initial) samples. Fumigated samples were placed in a desiccator with chloroform and the head space was evacuated until the chloroform boiled. Fumigated soil was then extracted in 2N KCl, as above. Ammonium-N and nitrate-N (mg/L) in the KCl extracts were determined spectrophotometrically using the phenate and cadmium reduction methods, respectively (Technicon 1985). Some soil extracts were misplaced or lost during power outages, so data from some plots are missing. However, there was at least one replicate plot per treatment of remaining samples. Soil bulk density was calculated from the September samples.
REFERENCES :
Technicon Instrument Corp. 1985. AutoAnalyzer II. – Tarrytown, NY.
Zimmerman, J.K., W.M. Pulliam, D.J. Lodge, V. Quiñones-Orfila, N. Fetcher, S. Guzman-Grajales, J.A. Parrotta, C.E. Asbury, L.R. Walker and R.B. Waide. 1995. Nitrogen immobilization by decomposing woody debris and the recovery of tropical wet forest from Hurricane damage. Oikos 72:314-322.
CROSS-REFERENCES (other data sets related to this one): LTERDBAS#51: MRCE/LTER Soil and Microbial Biomass Nitrogen; LTERDBAS #93: Litter decomposition in tabonuco forest before Hugo; LTERDBAS #94: Litterfall of the tabonuco forest before Hurricane Hugo; LTERDBAS #95: Litterfall along topographic gradients at lower Bisley; LTERDBAS #111: Litterfall in tabonuco (subtropical wet) forest in the Luquillo Experimental Forest, Puerto Rico (MRCE Litterfall data); LTERDBAS #115: Short-term disappearance of foliar litter of three tree species native to rain forest of Puerto Rico
STORAGE SITES (of data files): Data Management Cabinet 333-01, ITES, UPR Rio Piedras Campus
INVESTIGATOR'S ASSIGNED KEYWORDS: subtropical wet ecosystem, nitrogen, soils, hurricane, microbial nutrient immobilization
LEF LTER OFFICIAL KEYWORDS (See table): EV, Subtropical Wet Ecosystem, Nitrogen, Soils, Hurricane, Other (Microbial Nutrient Immobilization), Peer-Reviewed Journal, Book Chapter
PUBLICATIONS:
Lodge, D.J., and W.H.
McDowell. 1991. Summary of ecosystem-level effects of
Atlantic hurricanes. Biotropica 23:
373-378.
Lodge, D.J., W.H. McDowell, and C.P. McSwiney. 1994. The importance of nutrient pulses in tropical forests. Trends in Ecology and Evolution 9: 384-387.
Miller, R.M., and D.J. Lodge. 1997. Fungal responses to disturbance - Agriculture and Forestry. Pp. 65-84 In The Mycota, Vol. V. Environmental and Microbial Relationships. K. Esser, P.A. Lemke and D.T. Wicklow, Eds. Springer Verlag.
Miller, R.M., and D.J. Lodge. 2007. Fungal responses to disturbance - Agriculture and Forestry. Pp. 44-67 In The Mycota, 2nd Ed., IV, Environmental and Microbial Relationships (K. Esser, P. Kubicek & I.S. Druzhinina, eds) Springer-Verlag, Berlin.
Zimmerman, J.K., W.M. Pulliam, D.J. Lodge, V. Quiñones-Orfila, N. Fetcher, S. Guzman-Grajales, J.A. Parrotta, C.E. Asbury, L.R. Walker and R.B. Waide. 1995. Nitrogen immobilization by decomposing woody debris and the recovery of tropical wet forest from Hurricane damage. Oikos 72:314-322.
RESTRICTED UNRESTRICTED __X__
REASONS TO RESTRICT DATA IN THIS DATA SET BEYOND ITS TWO YEAR POLICY PERIOD*:
*WILL HAVE TO BE APPROVED BY LTER PRINCIPAL INVESTIGATORS: N. BROKAW, A. LUGO
___"File"
copy only: Data
Management will only file an electronic copy of the data file and its
documentation
___"Enter" data on-line: Data
Management will be in charge of entering the data on computer files (Contact Eda C. Melendez)
SITES
DESCRIPTIONS:
El Verde research area: This area is located at
about 400 m.a.s.l. at 18° 20' N, 65° 49' W, in the Luquillo Experimental
Forest, Puerto Rico. Annual rainfall is 350 cm distributed more or less evenly
throughout the year. The site lies within Holdridge's subtropical wet forest.
Forest in the region are relatively undistributed foress dominated by tabonuco
(Dacryodes excelsa), Manilkara bidendata, Sloaena berteriana,
and secondary forests dominated by Cesarea arborea.
Pico del Este research area: This area is located at about 1000 m.a.s.l. at 18°16'N, 65°46'W, in the Luquillo Experimental Forest, Puerto Rico. Annual rainfall is 420 cm, a large proportion of which is in the form of fog and mist. The site lies within Holdridge's low montane forest. The forest is cloud forest (also called elfin or dwarf forest) dominated by Tababuia rigida, Ocotea spathulata, and Eugenia borinquensis.
Geographical positional system (GPS) Coordinates for each location:
location |
latitude |
longitude |
| El Verde | 18°19' N | 65° 49' W |
| Pico del Este | 18° 16' N | 65° 45' W |
File Name or # above (all in which the variable appears) |
1 | 1 | 1 | 1 | 1 |
Abbreviation (as it appears on the data file) |
Sample_Date | Sample_Label | SampleID | Treatment | Sample_Subplot_coordinates |
| Sample Date | Sample Label | Sample Identification | Plot Treatment | Sample Subplot Coordinates | |
| Date when sample was collected at the field | Label assigned in the field to sample | Sample Identifier assigned in the field or lab | Litter and debris removal and fertilization treatments that were applied to plots established within replicate blocks. | Location of soil cores within 10 x 10 m plot | |
| meters | |||||
| 0.1 | |||||
| 1-1-1 to 4-5-4; B II P4; B II P5; B II P3; B III P4; B III P5 | 1-1-1 to 4-5-4; B II P4; B II P5; B II P3; B III P4; B III P5 | L = removal of all litter and woody debris, F = complete fertilization, C = control | |||
| datetime | alphanumeric | alphanumeric | character | decimal | |
VARIABLES (ATTRIBUTES):
| File Name or # above (all in which the variable appears) | 1 | 1 | 1 | 1 |
| Abbreviation(as it appears on the data file) | gWet_Weight_SoilCore | gWeightRocksRemoved | Total_gWet_Soil_Weight | Est_Total_gDry_Soil |
| NAME OF VARIABLE | Wet weight of soil in core | Weight of rocks removed | Total weight of wet soil | Estimated total dry weight of soil in core |
| DEFINITION OF VARIABLE | Total wet weight of soil in core 8.5 cm diam x 10 cm deep | Weight of rocks removed from soil core | Total weight of sampled wet soil | Estimated total dry weight of soil in core after removing weight of rocks and adjusting by fraction dry weight |
| UNIT | grams | grams | grams | grams |
| PRECISION | 0.1 | 0.01 | 0.01 | 0.1 |
| RANGE OR LIST OF VALUE | 290-675 | 0 - 101 | 110-510 | |
| DATA TYPE | decimal | decimal | decimal | decimal |
| MISSING DATA CODES |
VARIABLES (ATTRIBUTES):
| File Name or # above (all in which the variable appears) | 1 | 1 | 1 | 1 | 1 |
| Abbreviation(as it appears on the data file) | Soil_Bulk_Density | Sample_Treatment | gWetWtSoilExtracted_R1 | gWetWtSoilExtracted_R2 | SubSample_g_Wet_Wt |
| NAME OF VARIABLE | Bulk density of soil samples | Sample Treatment | Weight of soil sample extracted Replica 1 | Weight of soil sample extracted Replica 2 | Subsample wet weight for percent moisture |
| DEFINITION OF VARIABLE | Bulk density of soil per unit volume | Chloroform fumigated or control |
g wet weight of subsample of soil extracted in KCl in Replica 1 |
Wet weight of subsample of soil extracted in KCl in Replica 2 |
Weight of wet soil sample for % moisture determination |
| UNIT | gramsPerCubicCentimeter | grams | grams | grams | |
| PRECISION | 0.01 | 0.01 | 0.01 | 0.01 | |
| RANGE OR LIST OF VALUE | 0.2-0.88 | Fumigated, Control | 3.9-5.2 | 3.9-5.2 | 9-34 |
| DATA TYPE | decimal | alphanumeric | decimal | decimal | decimal |
| MISSING DATA CODES |
VARIABLES (ATTRIBUTES):
| File Name or # above (all in which the variable appears) | 1 | 1 | 1 | 1 |
| Abbreviation(as it appears on the data file) | SubSample_g_Dry_Wt | Fraction_Dry_Wt | Est_gDrySoil_Extracted_R1 | Est_gDrySoil_Extracted_R2 |
| NAME OF VARIABLE | Subsample dry weight for percent moisture | Dry weight fraction of fresh soil sample | Estimated total dry weight of soil in core Replica 1 | Estimated total dry weight of soil in core Replica 2 |
| DEFINITION OF VARIABLE | Weight of dry soil sample for % moisture determination | Oven dried weight of soil subsample divided by wet weight of sample | Estimated total dry weight of soil in core Replica 1 after removing weight of rocks and adjusting by fraction dry weight | Estimated total dry weight of soil in core Replica 2 after removing weight of rocks and adjusting by fraction dry weight |
| UNIT | grams | grams | grams | grams |
| PRECISION | 0.01 | 0.001 | 0.1 | 0.1 |
| RANGE OR LIST OF VALUE | 7-22 | 0.468-0.727 | 110-510 | |
| DATA TYPE | decimal | decimal | decimal | decimal |
| MISSING DATA CODES |
COMPUTATIONAL METHODS:
FOR DATA MANAGER USE ONLY
DATE OF LAST REVIEW:
May 29, 2009
DATE OF LAST ENTRY : September 15, 1990
STAGE OF DATA SET MANAGEMENT (dates) :
RECEIVED: April 29, 2009
ENTERED: April 29, 2009
FILED ON-LINE: May 3, 2009
REVIEWED BY RESEARCHER:
FILING MEDIA:
NAME OF
DOCUMENTATION FILE: lterdb51.htm
NAME OF ON - LINE CATALOG: LTERDBAS
RECORD #: 51
DOCUMENT TYPE: digital
PRIORITY TO BE ENTERED: N/A
Rev. date of this form: 28 July 200/ 15 July 2001/June 9, 2003/March 16, 2004/12 April 2005/ 8 November 2005