Log response ratios to seagrass edge and fragmentation effects from peer-reviewed literature

Website: https://www.bco-dmo.org/dataset/864783
Data Type: Other Field Results, document
Version: 1
Version Date: 2021-12-01

Project
» Collaborative Research: Habitat fragmentation effects on fish diversity at landscape scales: experimental tests of multiple mechanisms (Habitat Fragmentation)
ContributorsAffiliationRole
Fodrie, F. JoelUniversity of North Carolina at Chapel Hill (UNC-Chapel Hill)Principal Investigator
Byers, James E.University of Georgia (UGA)Scientist
Yeager, LaurenUniversity of Texas - Marine Science Institute (UTMSI)Scientist
Yarnall, AmyUniversity of North Carolina at Chapel Hill (UNC-Chapel Hill)Contact
Heyl, TaylorWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager
Rauch, ShannonWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
This dataset was obtained by searching the Institute of Science Information's (ISI) Web of Science, last accessed on May 13, 2021, to gather peer-reviewed literature examining edge effects and fragmentation effects on biogenic complexity, faunal densities, and predation in seagrass ecosystems. The dataset represents log response ratios to seagrass edge and fragmentation effects from these studies.


Coverage

Spatial Extent: N:59.92275 E:-0.39808616973 S:-34.25 W:-9.740833
Temporal Extent: 1990-06 - 2017-08

Methods & Sampling

Literature search and meta-analysis inclusion criteria
We conducted a search using the Institute of Science Information's (ISI) Web of Science (last accessed on May 13, 2021) to gather peer-reviewed literature examining edge effects and fragmentation effects on biogenic complexity, faunal densities, and predation in seagrass ecosystems. Search terms included 1) seagrass AND 2) edge effects OR fragmentation effects AND 3) density OR predation OR survival OR mortality OR trophic interactions. We supplemented this database with additional articles known to us. All candidate studies were judged for inclusion in our meta-analysis based on the following criteria: 1) The study was an original experiment in a mesocosm or natural setting providing edge effect data (i.e., responses in patch edges vs. interiors) or fragmentation effect data (i.e., responses in fragmented vs. continuous landscapes) for one or more of our response metrics of interest in extractable form (i.e., table, figure, or text). Response metrics were natural seagrass shoot density, faunal density, and predation survival. Initially, we considered several metrics of biogenic complexity because they may respond to habitat configuration differently, yet shoot density was ultimately chosen as it was the most common metric reported. Shoot density data were only extracted from studies also examining faunal response metrics, because we were interested in examining faunal-habitat relationships in the context of proximate (e.g., shoot density) and ultimate (e.g., edge, fragmentation) drivers. For faunal density responses, if data for “nested” taxonomic levels were provided (e.g., fish, flounder), we extracted data for the lowest taxonomic level available. Prey survival responses included data expressed as, or converted to, proportion survival or survival time (e.g., h to consumption) of sessile or tethered prey. Only survival from uninhibited predator exposure was considered. 2) The response metric(s) included the mean, sample size, and either standard error (SE), standard deviation (SD), or confidence interval (CI). 3) Levels of edge effects (e.g., edge, interior) and fragmentation (e.g., fragmented, continuous) were typically expressed as discrete categories. Therefore, we accepted the operational definitions used by these studies, but also included meta-data such as edge/interior widths and distances, and fragmentation degree in our database to illustrate the range of definitions used across studies. All included studies examined fragmentation as a state (i.e., configuration), rather than an active process (i.e., changing configuration through time). For studies that included more than two discrete levels of edge (e.g., integer distances) or fragmentation (e.g., continuous, patchy, very patchy), only the most extreme levels were included in effect size calculations (e.g., the distances closest to the patch edge and center; the most continuous and fragmented landscape classifications). Figure data was extracted using DataThief III software (Tummers, 2006).

Calculating Log Response Ratios
Refer to the attached Supplemental File, "864783_Calculating_Log_Response_Ratios.pdf"  for a description of how the log response ratios were calculated.


Data Processing Description

Data Processing:
All data were entered electronically into an Excel spreadsheet. Figure data were extracted using DataThief III software (Tummers, 2006). To quantify edge and fragmentation effects across studies, we calculated log response ratios (LRRs) using methods described by Hedges et al. (1999) within the R computing environment (v. 4.1.0; R Core Team 2021).

BCO-DMO Processing:
- Added columns for month_start, year_start, month_end, year_end;
- Adjusted field/parameter names to comply with BCO-DMO naming conventions;
- Removed commas or replaced them with semi-colons;
- Added a conventional header with dataset name, PI names, version date.


[ table of contents | back to top ]

Data Files

File
comparing_edge_frag_LRR.csv
(Comma Separated Values (.csv), 102.03 KB)
MD5:65b4d1f9c32cdd7bb0c450f61ce47f27
Primary data file for dataset ID 864783

[ table of contents | back to top ]

Supplemental Files

File
Calculating Log Response Ratios
filename: 864783_Calculating_Log_Response_Ratios.pdf
(Portable Document Format (.pdf), 465.77 KB)
MD5:19f41a8d54b8ac3387253c1a9fcdccdb
References
filename: 864783_Complete_References.pdf
(Portable Document Format (.pdf), 428.86 KB)
MD5:48823ed7460e21dcb875685574b2b96c

[ table of contents | back to top ]

Related Publications

Hedges, L. V., Gurevitch, J., & Curtis, P. S. (1999). THE META-ANALYSIS OF RESPONSE RATIOS IN EXPERIMENTAL ECOLOGY. Ecology, 80(4), 1150–1156. doi:10.1890/0012-9658(1999)080[1150:tmaorr]2.0.co;2
Results

[ table of contents | back to top ]

Parameters

ParameterDescriptionUnits
study_typeThe focus of the study: edge effects or fragmentation effects, references may have both options in different rows unitless
referenceShort formatted reference (i.e., Able 2005); for complete citations refer the Supplemental File "864783_Complete_References.pdf". unitless
month_startApproximate sampling start month of study unitless
year_startApproximate sampling start year of study unitless
month_endApproximate sampling end month of study unitless
year_endApproximate sampling end year of study unitless
latitudeApproximate sampling latitude North decimal degrees
longitudeApproximate sampling longitude East (West is negative) decimal degrees
locationName of the location where the study was conducted unitless
global_regionGlobal region in which the study took place: North America, Europe, Asia-Pacific; Africa unitless
sg_typeDenotes whether the experiement or survey took place with natural or artifical seagrass unitless
sg_sppSpecies of (natural or artificially immitated) seagrass in study; commas between species if more than one unitless
frag_defFor study_type = fragmentation; Operational definitions of the fragmented landscape Given in cell
cont_defFor study_type = fragmentation; Operational definitions of the continuous landscape Given in cell
edge_defFor study_type = edge effect; Operational definitions of the patch edge unitless
int_defFor study_type = edge effect; Operational definitions of the patch interior unitless
covariateIf the publication separated results by a covariate (e.g., site, month, patch size), covariate decribed here unitless
covariate_levelThe level of the covariate (e.g., site a, site b); if 'all', data from non-independent spatial or temporal replicates have be combined according to Hedges et al. (1999) unitless
data_sourceTable, Figure, or Text page from which the data were collected unitless
collectedData collection method (e.g., gear type) used by the original publication author(s) unitless
target_taxonFaunal taxonomic level for which density or survival data were available (NA if biotic response is shoot density) unitless
broad_taxonLowest available faunal taxonomic level for LRRi (NA if biotic response is shoot density) unitless
lowest_taxonBroad faunal taxon or guild: fish, invertebrate, nekton (NA if biotic response is shoot density) unitless
guildHabitat zonation of fauna unitless
biotic_responseShoot density, (faunal) Density, or Survival unitless
RRResponse Ratio: The ratio of the mean response in patch edges (X_e) or fragmented landscapes (X_f) over the mean response in patch interiors (X_i) or continuous landscapes (X_c), respectively unitless
LRRiLn of the response ratio units
ViSampling error term or within-experiment variance as calculated by Hedges et al. (1999) units

[ table of contents | back to top ]

Project Information

Collaborative Research: Habitat fragmentation effects on fish diversity at landscape scales: experimental tests of multiple mechanisms (Habitat Fragmentation)

Coverage: North Carolina


Amount and quality of habitat is thought to be of fundamental importance to maintaining coastal marine ecosystems. This research will use large-scale field experiments to help understand how and why fish populations respond to fragmentation of seagrass habitats. The question is complex because increased fragmentation in seagrass beds decreases the amount and also the configuration of the habitat (one patch splits into many, patches become further apart, the amount of edge increases, etc). Previous work by the investigators in natural seagrass meadows provided evidence that fragmentation interacts with amount of habitat to influence the community dynamics of fishes in coastal marine landscapes. Specifically, fragmentation had no effect when the habitat was large, but had a negative effect when habitat was smaller. In this study, the investigators will build artificial seagrass habitat to use in a series of manipulative field experiments at an ambitious scale. The results will provide new, more specific information about how coastal fish community dynamics are affected by changes in overall amount and fragmentation of seagrass habitat, in concert with factors such as disturbance, larval dispersal, and wave energy. The project will support two early-career investigators, inform habitat conservation strategies for coastal management, and provide training opportunities for graduate and undergraduate students. The investigators plan to target students from underrepresented groups for the research opportunities.

Building on previous research in seagrass environments, this research will conduct a series of field experiments approach at novel, yet relevant scales, to test how habitat area and fragmentation affect fish diversity and productivity. Specifically, 15 by 15-m seagrass beds will be created using artificial seagrass units (ASUs) that control for within-patch-level (~1-10 m2) factors such as shoot density and length. The investigators will employ ASUs to manipulate total habitat area and the degree of fragmentation within seagrass beds in a temperate estuary in North Carolina. In year one, response of the fishes that colonize these landscapes will be measured as abundance, biomass, community structure, as well as taxonomic and functional diversity. Targeted ASU removals will then follow to determine species-specific responses to habitat disturbance. In year two, the landscape array and sampling regime will be doubled, and half of the landscapes will be seeded with post-larval fish of low dispersal ability to test whether pre- or post-recruitment processes drive landscape-scale patterns. In year three, the role of wave exposure (a natural driver of seagrass fragmentation) in mediating fish community response to landscape configuration will be tested by deploying ASU meadows across low and high energy environments.



[ table of contents | back to top ]

Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

[ table of contents | back to top ]