LTERDB105-Enclosure/exclosure experiments in a montane Puerto Rican stream examining direct and indirect effects of two dominant taxa of atyid (Atyidae) shrimp, Atya lanipes Holthius and Xiphocaris elongata Guerin-Meneville

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PERSON(S) COMPLETING THIS FORM: E-MAIL ADDRESS:

Gail A. Blake
Eda C. Melendez-Colom	emelendez@lternet.edu

DATA SET IDENTIFIER: Enclosure/exclosure experiments in a montane Puerto Rican stream examining direct and indirect effects of two dominant taxa of atyid (Atyidae) shrimp, Atya lanipes Holthius and Xiphocaris elongata Guerin-Meneville (Shrimp/ Algae/ Oecologia (1993))

PROJECT TITLE: Influence of Decapods on Ecosystem Processes

PROJECT DESCRIPTION: Three experiments were performed to study the influence of decapods on ecosystem processes. In the first one (catalogued as LTERDBAS #104) the hypothesis that differences in macrobiotic assemblages can lead to differences in the quantity and quality of organic matter in benthic depositional environmentsamong streams in montane Puerto Rico was tested. The experimental results were consistent with findings of an independent survey of six streams in four different drainages. Four streams that had an abundance of omnivorous shrimps but lacked predaceous fishes, had extremely low levels of fine benthic organic and inorganic material. In contrast, two streams that had low densities of shrimps and contained predaceous fishes had significantly higher levels. Results showed a strong linkage between species and ecosystem characteristics: interstream differences in the quantity and quality of fine benthic organic matter resources were determined by the nature of the macrobiotic assemblage. Furthermore, patterns in the distribution of shrimp assemblages reflected landscape patterns in the benthic depositional environment among streams.

In the second experiment (LTERDBAS #105) the role of freshwater shrimp, which dominate the faunal biomass of many tropical headwater streams, was studied. The enclosure/exclosure experiments in a montane Puerto Rican stream the direct and indirect effects of two dominant taxa of atyid (Atyidae) shrimp, Atya lanipes Holthius and Xiphocaris elongata Guerin-Meneville was examined. Both shrimp taxa caused significant reductions in sediment cover on rock substrata, reducing sedimentation and enhancing algal biovolume on clay tiles in cages.We evaluated the mechanism by which A. lanipes influences algae and benthic insects by comparing patterns of algal biomass, taxonomic composition and shrimp-presence treatments both with and without manual sediment removal. The shrimp exclusion treatment without manual sediment removal had significantly lower algal biomass and greater sedimentation than all other treatments. The treatment in which shrimp were excluded but sediment was manually removed, however, accrued almost the same algal biovolume as the shrimp enclosure treatment, supporting the hypothesis that sediment removal enhances the biovolume of understory algal taxa.

The effects of biotic (shrimp) and abiotic (discharge) factors on the depositional environment were quantified in a montane stream in Puerto Rico in a third experiment (LTERDBAS #106). Electricity was used experimentally to exclude large (approximately >1cm in length) biota without artificially increasing sedimentation as in cage enclosure/exclosure experiments in stream systems. Unelectrified control substrata had natural high densities of atyid shrimp. Atyid shrimp can significantly affect the accumulation of organic and inorganic materials on rock substrata in stream pools between high-discharge events.

LTER CORE AREAS: (Annotate all that apply)

Population Dynamics

LEF LTER 1 RESEARCH TOPIC: (Annotate all that apply)

Spatial and Temporal Distribution of Populations

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):

Data File No.	Data File Identifier	On-Line Filename	Starting Date	Periodicity of sample	End Period
1	Percentage of tile covered by silt on each observation date in Atya lanipes experiments (February 23 to March,1990). Figures 2, 3, and 4 Atya lanipes.	fig234atya.txt	February 23, 1990	once	July 27, 1990
2	Percentage of tile covered by silt on each observation date in Xiphocaris elongata experiments (July 6 to 27, 1990). Fig 2, 3, and 4 Xiphocaris elongata.	fig234xipho.txt	July 6, 1990	once	July 27, 1990
3	Mean total algal biovolume for each treatment in Atya lanipes experiment. Fig 5 Atya lanipes.	fig5atya.txt	February 23, 1990	once	March 25, 1990
4	Mean total algal biovolume for each treatment in Xiphocaris experriment (Fig 5 Xiphocaris elongata )	fig5xipho.txt	July 6, 1990	once	July 27, 1990
5	Mean numbers of Xiphocaris elongata (XIPHO), Atya species (ATYA) and Machrobrachium species (MASCRO) per outside tile over 5 minutes observation. Table 1.	table1.txt	February 23, 1990	once	July 27, 1990

RESEARCH LOCATION: Experiments were run in a pool of the Quebrada Toronja, a first-order stream located within the Rio Espiritu Santo watershed in the Luquillo Experimental Forest in northeast Puerto Rico

INVESTIGATORS:

PRINCIPAL INVESTIGATORS E-MAIL address

Catherine M. Pringle

cpringle@uga.edu

OTHER RESEARCHERS E-MAIL address

Gail A. Blake

Alan P. Covich acovich@lternet.edu

Karen M. Buzby

Amy Finley

CONTACT PERSONS E-MAIL address Phone Number (Include area code)

Catherine M. Pringle

cpringle@uga.edu

(706) 542-1120

SOURCE OF FUNDING (SPONSOR): NSF BSR-87-17746 and BSR-91-07772

DATA SET ABSTRACT: Freshwater shrimp dominate the faunal biomass of many tropical headwater streams: however, their role in community organization is unclear. Enclosure/exclosure experiments in a montane Puerto Rican stream examined direct and indirect effects of two dominant taxa of atyid (Atyidae) shrimp, Atya lanipes Holthius and Xiphocaris elongata Guerin-Meneville. Both shrimp taxa caused significant reductions in sediment cover on rock substrata, reducing sedimentation and enhancing algal biovolume on clay tiles in cages. When tiles incubated in shrimp exclosures for 2 wks were placed outside of cages, atyid shrimp removed 100% of sediment cover within a 30 min. observation period. Atyid shrimp appear to play an important role in stream recovery after high discharge events in rapidly removing sediments and detritus deposited on benthic substrata in pools. We evaluated the mechanism by which A. lanipes influences algae and benthic insects by comparing patterns of algal biomass, taxonomic composition and shrimp-presence treatments both with and without manual sediment removal. The shrimp exclusion treatment without manual sediment removal had significantly lower algal biomass and greater sedimentation than all other treatments. The treatment in which shrimp were excluded but sediment was manually removed, however, accrued almost the same algal biovolume as the shrimp enclosure treatment, supporting the hypothesis that sediment removal enhances the biovolume of understory algal taxa. Algal community composition was similar between stream bottom bedrock exposed to natural densities of shrimp and all experimental treatments for both Atya and Xiphocaris: a diatom community strongly dominated (78-95%) by the adnate taxon, Achnanthes lanceolata Breb ex. Kutz. Atyid shrimp are important in determining the distribution and abundance of benthic insects through both direct and indirect effects. Sessile, retreat-building chironomid larvae (Chironomidae: Diptera) are negatively affected by both A. lanipes and X.elongata, through direct removal by foraging activities and/or indirectly through depression of sediment resources available to larvae for the construction of retreats. In contrast, the mobile grazer, Cleodes maculipes (Baetidae: Ephemeroptera) was not adversely affected and atyid shrimp have the potential to exert positive indirect effects on this taxon by facilitating its exploitation of algal resources and/or through enhancement of understory algal food resources through sediment removal.

DATA SET METHODS: Shrimp enclosure/exclosure experiments assessed effects of Atya lanipes Holthius and Xiphocaris elongata Guerin-Menevil on sedimentation, insect abundance and algal communities in the Río Toronja. Two consecutive experiments examined effects of the A. lanipes (23 February - 25 March 1990) and X. elongata (6-27 July), respectively. For a more detailed description of the methodology see publication.

REFERENCES:

CROSS REFERENCE(other data sets related to this one): LTERDBAS 104 :Shrimp/ Organic Matter/ Ecology (1999); LTERDBAS 105 :Shrimp/ Algae/ Oecologia (1993); LTERDBAS 106 : Shrimp/ Algae/ Can. J. Aquat. Sci. (1994)

SAMPLE LOCATION: N/A

STORAGE SITES: Data Management Cabinet DM-002 Drawer #3

INVESTIGATOR'S ASSIGNED KEYWORDS: Tropical Stream, Community structure, Sedimentation, Shrimp, Algal periphyton

LEF LTER OFFICIAL KEYWORDS (See table): Q TORONJA, RIVER, COMMUNITY COMPOSITION, SEDIMENTATION, DECAPODS, PEER REVIEWED JOURNAL

PUBLICATIONS:

Pringle, C.M.; Blake, G.A.; Covich, A.P.; Buzby, K.M.; Finley A. (1993) Effects of omnivorous shrimp in a montane tropical stream: sediment removal, disturbance of sessile invertebrates and enhancement of algal biomass Oecologia 93:1-11

DISSEMINATION: UNRESTRICTED

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

SITES DESCRIPTIONS: The site was the Quebrada Toranja stream and the sampling was done in pools using a 75 cm long by 25cm wide by 24cm deep cage.

Geographical positional system (GPS) Coordinates for each location:

location

latitude

longitude

VARIABLES (ATTRIBUTES):

FILE NAME OR #ABOVE (all in which the variable appears)
1, 3 2,4 1,2 1,2 1,2 1,2

ABBREVIATION (as it appears on the data file)
Treatment1 Treatment2 Day Cloedesmaculipes Chironomidae Percentofsilt

NAME OF VARIABLE
Treatment1 Treatment2 Day Number of Cloedes maculipes Number of chironomidae Percent of silt

DEFINITION OF VARIABLE
The two treatments were
Shrimp and
No Shrimp. No data is missing in this field. The three treatments were
Shrimp
No Shrimp
Outside Cage-Sampling took place outside of the shrimp cage exposed to natural densities of shrimp. No data is missing in this field. The number of the day sampled. For atya: 1,...,30,
xypho: 1,...,18. No data is missing in this field. The number per tile of mayfly grazer Cloeodes maculipes sampled for each of the three treatments. With similar and adequate sampling, the data should be reproducable. For atya: 0,...,56; For xypho:
{1,...,98}. No data is missing in this field.
The number of larval chironomid retreats per tile s for each of the three treatments. With similar and adequate sampling, the data should be reproducable. For atya: 0,...,235; For xypho:
{1,...,98}. No data is missing in this field.
The percentage of tile surface covered by silt for each of the three treatments. With similar and adequate sampling, the data should be reproducable. atya file:
{4,...,97.5
xypho file:
{1,...,98}atya file:
{4,...,97.5
xypho file:
{1,...,98}. No data is missing in this field.

UNIT
number number

PRECISION

RANGE OR LIST OF VALUES
Shrimp = 2 mature shrimp were added to the cage, No Shrimp = Shrimp were removed from the cage. Shrimp = 4 mature shrimp were added to the cage and silt was removed every 1 to 3 days, No Shrimp = Shrimp were removed from the cage and the silt was removed every 1 to 3 days, Outside Cage = Sampling took place outside of the shrimp cage exposed to natural densities of shrimp {1,...,30} {1,...,98} {0,...,235} {1,...,98}

DATA TYPE
alphanumeric alphanumeric integer integer
integer

real

MISSING DATA CODES

VARIABLES (ATTRIBUTES):

FILE NAME OR #ABOVE (all in which the variable appears)
3,4 3,4 3,4 3,4 3,4 3

ABBREVIATION (as it appears on the data file)
A_lan A_min A_exi Cocconeis Gom_spp Opeph_mar

NAME OF VARIABLE
Achnanthes lanipes Achnanthes minutissima Achnanthes exigua Gomphonema spp. Cocconeis placentula Opephora martyi

DEFINITION OF VARIABLE
The algal biovolume of Achnanthes lanipes for the different treatments in the presence of
Atya spp. Freshwater shrimp. No data is missing in this field. The algal biovolume of Achnanthes minutissma for the different treatments in the presence of
Atya spp. Freshwater shrimp. No data is missing in this field. The algal biovolume of Achnanthes exigua for the different treatments in the presence of
Atya spp. Freshwater shrimp. No data is missing in this field. The algal biovolume of Cocconeis placentula for the different treatments in the presence of
Atya spp. Freshwater shrimp. No data is missing in this field. The algal biovolume of Gomphonema spp. for the different treatments in the presence of
Atya spp. Freshwater shrimp. No data is missing in this field. The algal biovolume of Opephora martyi for the different treatments in the presence of Atya spp.
Freshwater shrimp.

UNIT
grams per meter squared grams per meter squared grams per meter squared grams per meter squared grams per meter squared grams per meter squared

PRECISION
If the same sampling with adequate sample size should lead to highly reproducable If the same sampling with adequate sample size should lead to highly reproducable If the same sampling with adequate sample size should lead to highly reproducable If the same sampling with adequate sample size should lead to highly reproducable If the same sampling with adequate sample size should lead to highly reproducable If the same sampling with adequate sample size should lead to highly reproducable

RANGE OR LIST OF VALUES
{35.08,...,239.09} {0.81,...,6.65} {0.2,...,5.31} {0,...,4.08} {0,...,0.43}

DATA TYPE
real real real real real real

MISSING DATA CODES

VARIABLES (ATTRIBUTES):

FILE NAME OR #ABOVE (all in which the variable appears)
3,4 4 5 5 5 5

ABBREVIATION (as it appears on the data file)
Mougeotia Nitz_1 Date x_elongata atya macrobrachium

NAME OF VARIABLE
Mougeotia Nitzchia spp. Sampling date
Number of x. elongata visiting outside of the cage
Number of atya visiting outside of the cage
Number of macrobrachium visiting outside of the cage

DEFINITION OF VARIABLE
The algal biovolume of Mougeotia for the different treatments in the presence of Atya spp.
Freshwater shrimp. If the same sampling with adequate sample size should lead to highly reproducable The algal biovolume of Nitzchia spp. for the different treatments in the presence of Atya spp.
Freshwater shrimp. If the same sampling with adequate sample size should lead to highly reproducable The date the sampling took place The number of x. elongata visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable The number of atya visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable The number of macrobrachium visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable

UNIT
grams per meter squared grams per meter squared number number number

PRECISION

RANGE OR LIST OF VALUES
{0,...,73.33} {0,...,1.65} {0,...,7} {0,1,2}

DATA TYPE
real real datetime integer integer integer

MISSING DATA CODES

COMPUTATIONAL METHODS:

Variable Name Formula

FOR DATA MANAGER USE ONLY

DATE OF LAST REVIEW: April 9, 2009

DATE OF LAST ENTRY: August 26 2000

STAGE OF DATA SET MANAGEMENT (dates):

RECEIVED: 06/2000

ENTERED: FILED 07/2000

ON-LINE: 10/2000

REVIEWED BY RESEARCHER

FILING MEDIA:

NAME OF DOCUMENTATION FILE: lterdb105.htm

NAME OF DATA FILE: [Fig###{atya,xypho},table1].txt

NAME OF ON - LINE CATALOG: LTERDBAS
RECORD #: 105
DOCUMENT TYPE: magnetic media
PRIORITY TO BE ENTERED: N/A

Gail A. Blake
Alan P. Covich	acovich@lternet.edu
Karen M. Buzby
Amy Finley

FILE NAME OR #ABOVE (all in which the variable appears)	1, 3	2,4	1,2	1,2	1,2	1,2
ABBREVIATION (as it appears on the data file)	Treatment1	Treatment2	Day	Cloedesmaculipes	Chironomidae	Percentofsilt
NAME OF VARIABLE	Treatment1	Treatment2	Day	Number of Cloedes maculipes	Number of chironomidae	Percent of silt
DEFINITION OF VARIABLE	The two treatments were Shrimp and No Shrimp. No data is missing in this field.	The three treatments were Shrimp No Shrimp Outside Cage-Sampling took place outside of the shrimp cage exposed to natural densities of shrimp. No data is missing in this field.	The number of the day sampled. For atya: 1,...,30, xypho: 1,...,18. No data is missing in this field.	The number per tile of mayfly grazer Cloeodes maculipes sampled for each of the three treatments. With similar and adequate sampling, the data should be reproducable. For atya: 0,...,56; For xypho: {1,...,98}. No data is missing in this field.	The number of larval chironomid retreats per tile s for each of the three treatments. With similar and adequate sampling, the data should be reproducable. For atya: 0,...,235; For xypho: {1,...,98}. No data is missing in this field.	The percentage of tile surface covered by silt for each of the three treatments. With similar and adequate sampling, the data should be reproducable. atya file: {4,...,97.5 xypho file: {1,...,98}atya file: {4,...,97.5 xypho file: {1,...,98}. No data is missing in this field.
UNIT				number	number
PRECISION
RANGE OR LIST OF VALUES	Shrimp = 2 mature shrimp were added to the cage, No Shrimp = Shrimp were removed from the cage.	Shrimp = 4 mature shrimp were added to the cage and silt was removed every 1 to 3 days, No Shrimp = Shrimp were removed from the cage and the silt was removed every 1 to 3 days, Outside Cage = Sampling took place outside of the shrimp cage exposed to natural densities of shrimp	{1,...,30}	{1,...,98}	{0,...,235}	{1,...,98}
DATA TYPE	alphanumeric	alphanumeric	integer	integer	integer	real
MISSING DATA CODES

FILE NAME OR #ABOVE (all in which the variable appears)	3,4	3,4	3,4	3,4	3,4	3
ABBREVIATION (as it appears on the data file)	A_lan	A_min	A_exi	Cocconeis	Gom_spp	Opeph_mar
NAME OF VARIABLE	Achnanthes lanipes	Achnanthes minutissima	Achnanthes exigua	Gomphonema spp.	Cocconeis placentula	Opephora martyi
DEFINITION OF VARIABLE	The algal biovolume of Achnanthes lanipes for the different treatments in the presence of Atya spp. Freshwater shrimp. No data is missing in this field.	The algal biovolume of Achnanthes minutissma for the different treatments in the presence of Atya spp. Freshwater shrimp. No data is missing in this field.	The algal biovolume of Achnanthes exigua for the different treatments in the presence of Atya spp. Freshwater shrimp. No data is missing in this field.	The algal biovolume of Cocconeis placentula for the different treatments in the presence of Atya spp. Freshwater shrimp. No data is missing in this field.	The algal biovolume of Gomphonema spp. for the different treatments in the presence of Atya spp. Freshwater shrimp. No data is missing in this field.	The algal biovolume of Opephora martyi for the different treatments in the presence of Atya spp. Freshwater shrimp.
UNIT	grams per meter squared	grams per meter squared	grams per meter squared	grams per meter squared	grams per meter squared	grams per meter squared
PRECISION	If the same sampling with adequate sample size should lead to highly reproducable	If the same sampling with adequate sample size should lead to highly reproducable	If the same sampling with adequate sample size should lead to highly reproducable	If the same sampling with adequate sample size should lead to highly reproducable	If the same sampling with adequate sample size should lead to highly reproducable	If the same sampling with adequate sample size should lead to highly reproducable
RANGE OR LIST OF VALUES	{35.08,...,239.09}	{0.81,...,6.65}	{0.2,...,5.31}	{0,...,4.08}		{0,...,0.43}
DATA TYPE	real	real	real	real	real	real
MISSING DATA CODES

FILE NAME OR #ABOVE (all in which the variable appears)	3,4	4	5	5	5	5
ABBREVIATION (as it appears on the data file)	Mougeotia	Nitz_1	Date	x_elongata	atya	macrobrachium
NAME OF VARIABLE	Mougeotia	Nitzchia spp.	Sampling date	Number of x. elongata visiting outside of the cage	Number of atya visiting outside of the cage	Number of macrobrachium visiting outside of the cage
DEFINITION OF VARIABLE	The algal biovolume of Mougeotia for the different treatments in the presence of Atya spp. Freshwater shrimp. If the same sampling with adequate sample size should lead to highly reproducable	The algal biovolume of Nitzchia spp. for the different treatments in the presence of Atya spp. Freshwater shrimp. If the same sampling with adequate sample size should lead to highly reproducable	The date the sampling took place	The number of x. elongata visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable	The number of atya visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable	The number of macrobrachium visiting tiles outside of the cage in number per tile. With similar and adequate sampling, the data should be reproducable
UNIT	grams per meter squared	grams per meter squared		number	number	number
PRECISION
RANGE OR LIST OF VALUES	{0,...,73.33}	{0,...,1.65}			{0,...,7}	{0,1,2}
DATA TYPE	real	real	datetime	integer	integer	integer
MISSING DATA CODES