Impact of habitat edges on density and secondary production of seagrass-associated fauna

Paul Bologna, Kenneth L. Heck

Research output: Contribution to journalArticleResearchpeer-review

85 Citations (Scopus)

Abstract

Species richness and abundance of seagrass-associated fauna are often positively correlated with seagrass biomass and structural complexity of the habitat. We found that while shoot density and plant biomass were greater in interior portions of turtle grass (Thalassia testudinum) beds than at edges, mean faunal density was significantly greater at edges than interior sites during 1994. This pattern was also observed in 1995, although differences were not significant. The four numerically dominant taxonomic groups showed varying degrees of elevated densities at edges of T. testudinum beds. Peracarids and polychaetes had significantly greater densities at edges of T. testudinum beds, while both decapods and gastropods showed dramatic temporal variability in density, with reversals in density between edge and interior occurring during the course of the study. This within-habitat variability in abundance may reflect both active accumulation of fauna at edges and settlement shadows for species with pelagic larvae. Active accumulation of highly mobile taxa seeking refuge in seagrass beds may explain the differences in density between edge and interior of T. testudinum patches for peracarids in 1994 and in 1995. Active accumulation at edges may also explain differences in density for some decapod taxa. Changes in gastropod densities between habitats may reflect larval settlement patterns. Results showed a distinct settlement shadow for the gastropod Caecum nitidum whose densities (primarily second stage protoconch) increased by more than an order of magnitude in 1994. Settlement shadows and post-settlement processes may also explain density differences of polychaetes between the edge and interior of T. testudinum patches. The differences in faunal densities between edge and interior habitat resulted in habitat specific differences in secondary production among the major taxonomic groups. On four of five dates in 1994 and in 1995, secondary production was greater at edge than interior locations. These unexpected results suggest that differences in faunal densities and secondary production between edges and interiors of seagrass patches represent a potentially vital link in seagrass trophic dynamics. If this elevated secondary production leads to increases in trophic transfer, then edges may serve as a significant trophic conduit to higher-level consumers in this system.

Original languageEnglish
Pages (from-to)1033-1044
Number of pages12
JournalEstuaries
Volume25
Issue number5
DOIs
StatePublished - 1 Jan 2002

Fingerprint

secondary productivity
secondary production
edge effects
seagrass
fauna
habitat
Biomass
Interiors (building)
gastropod
Gastropoda
habitats
Decapoda
Polychaeta
post-settlement process
larval settlement
settlement pattern
biomass
turtle
cecum
refuge

Cite this

@article{94f83f414159498cac9981ed99466aff,
title = "Impact of habitat edges on density and secondary production of seagrass-associated fauna",
abstract = "Species richness and abundance of seagrass-associated fauna are often positively correlated with seagrass biomass and structural complexity of the habitat. We found that while shoot density and plant biomass were greater in interior portions of turtle grass (Thalassia testudinum) beds than at edges, mean faunal density was significantly greater at edges than interior sites during 1994. This pattern was also observed in 1995, although differences were not significant. The four numerically dominant taxonomic groups showed varying degrees of elevated densities at edges of T. testudinum beds. Peracarids and polychaetes had significantly greater densities at edges of T. testudinum beds, while both decapods and gastropods showed dramatic temporal variability in density, with reversals in density between edge and interior occurring during the course of the study. This within-habitat variability in abundance may reflect both active accumulation of fauna at edges and settlement shadows for species with pelagic larvae. Active accumulation of highly mobile taxa seeking refuge in seagrass beds may explain the differences in density between edge and interior of T. testudinum patches for peracarids in 1994 and in 1995. Active accumulation at edges may also explain differences in density for some decapod taxa. Changes in gastropod densities between habitats may reflect larval settlement patterns. Results showed a distinct settlement shadow for the gastropod Caecum nitidum whose densities (primarily second stage protoconch) increased by more than an order of magnitude in 1994. Settlement shadows and post-settlement processes may also explain density differences of polychaetes between the edge and interior of T. testudinum patches. The differences in faunal densities between edge and interior habitat resulted in habitat specific differences in secondary production among the major taxonomic groups. On four of five dates in 1994 and in 1995, secondary production was greater at edge than interior locations. These unexpected results suggest that differences in faunal densities and secondary production between edges and interiors of seagrass patches represent a potentially vital link in seagrass trophic dynamics. If this elevated secondary production leads to increases in trophic transfer, then edges may serve as a significant trophic conduit to higher-level consumers in this system.",
author = "Paul Bologna and Heck, {Kenneth L.}",
year = "2002",
month = "1",
day = "1",
doi = "10.1007/BF02691350",
language = "English",
volume = "25",
pages = "1033--1044",
journal = "Estuaries",
issn = "0160-8347",
publisher = "Estuarine Research Federation",
number = "5",

}

Impact of habitat edges on density and secondary production of seagrass-associated fauna. / Bologna, Paul; Heck, Kenneth L.

In: Estuaries, Vol. 25, No. 5, 01.01.2002, p. 1033-1044.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Impact of habitat edges on density and secondary production of seagrass-associated fauna

AU - Bologna, Paul

AU - Heck, Kenneth L.

PY - 2002/1/1

Y1 - 2002/1/1

N2 - Species richness and abundance of seagrass-associated fauna are often positively correlated with seagrass biomass and structural complexity of the habitat. We found that while shoot density and plant biomass were greater in interior portions of turtle grass (Thalassia testudinum) beds than at edges, mean faunal density was significantly greater at edges than interior sites during 1994. This pattern was also observed in 1995, although differences were not significant. The four numerically dominant taxonomic groups showed varying degrees of elevated densities at edges of T. testudinum beds. Peracarids and polychaetes had significantly greater densities at edges of T. testudinum beds, while both decapods and gastropods showed dramatic temporal variability in density, with reversals in density between edge and interior occurring during the course of the study. This within-habitat variability in abundance may reflect both active accumulation of fauna at edges and settlement shadows for species with pelagic larvae. Active accumulation of highly mobile taxa seeking refuge in seagrass beds may explain the differences in density between edge and interior of T. testudinum patches for peracarids in 1994 and in 1995. Active accumulation at edges may also explain differences in density for some decapod taxa. Changes in gastropod densities between habitats may reflect larval settlement patterns. Results showed a distinct settlement shadow for the gastropod Caecum nitidum whose densities (primarily second stage protoconch) increased by more than an order of magnitude in 1994. Settlement shadows and post-settlement processes may also explain density differences of polychaetes between the edge and interior of T. testudinum patches. The differences in faunal densities between edge and interior habitat resulted in habitat specific differences in secondary production among the major taxonomic groups. On four of five dates in 1994 and in 1995, secondary production was greater at edge than interior locations. These unexpected results suggest that differences in faunal densities and secondary production between edges and interiors of seagrass patches represent a potentially vital link in seagrass trophic dynamics. If this elevated secondary production leads to increases in trophic transfer, then edges may serve as a significant trophic conduit to higher-level consumers in this system.

AB - Species richness and abundance of seagrass-associated fauna are often positively correlated with seagrass biomass and structural complexity of the habitat. We found that while shoot density and plant biomass were greater in interior portions of turtle grass (Thalassia testudinum) beds than at edges, mean faunal density was significantly greater at edges than interior sites during 1994. This pattern was also observed in 1995, although differences were not significant. The four numerically dominant taxonomic groups showed varying degrees of elevated densities at edges of T. testudinum beds. Peracarids and polychaetes had significantly greater densities at edges of T. testudinum beds, while both decapods and gastropods showed dramatic temporal variability in density, with reversals in density between edge and interior occurring during the course of the study. This within-habitat variability in abundance may reflect both active accumulation of fauna at edges and settlement shadows for species with pelagic larvae. Active accumulation of highly mobile taxa seeking refuge in seagrass beds may explain the differences in density between edge and interior of T. testudinum patches for peracarids in 1994 and in 1995. Active accumulation at edges may also explain differences in density for some decapod taxa. Changes in gastropod densities between habitats may reflect larval settlement patterns. Results showed a distinct settlement shadow for the gastropod Caecum nitidum whose densities (primarily second stage protoconch) increased by more than an order of magnitude in 1994. Settlement shadows and post-settlement processes may also explain density differences of polychaetes between the edge and interior of T. testudinum patches. The differences in faunal densities between edge and interior habitat resulted in habitat specific differences in secondary production among the major taxonomic groups. On four of five dates in 1994 and in 1995, secondary production was greater at edge than interior locations. These unexpected results suggest that differences in faunal densities and secondary production between edges and interiors of seagrass patches represent a potentially vital link in seagrass trophic dynamics. If this elevated secondary production leads to increases in trophic transfer, then edges may serve as a significant trophic conduit to higher-level consumers in this system.

UR - http://www.scopus.com/inward/record.url?scp=0036773535&partnerID=8YFLogxK

U2 - 10.1007/BF02691350

DO - 10.1007/BF02691350

M3 - Article

VL - 25

SP - 1033

EP - 1044

JO - Estuaries

JF - Estuaries

SN - 0160-8347

IS - 5

ER -