Brief description
Predation on newly settled individuals has been shown to shape marine sessile invertebrate communities of the northeast coast of North America. This study tests if this response can also be observed at other geographic locations that support different assemblage of marine sessile invertebrates. The effects of predation in early post-settlement assemblages were tested at two locations in Victoria; Workshops Jetty, Williamstown and Queenscliff Pier, Queenscliff during the summer of 2005-2006. At each site, early post-settlement assemblages of sessile invertebrates were established and subsequently exposed to a series of predation exclusion treatments of varying durations. This dataset gives the abundances of sessile invertebrates at Queenscliff Pier after an initial 4 day settlement period, and 20 and 40 days after these initial assemblages were exposed to three predation exclusion treatments: i) uncaged, no predator exclusion; ii) full 2 mm mesh cage, total predator exclusion; iii) full 10 mm mesh cage, exclusion of large predators only. In addition two cage control treatments were established to identify if the cages themselves caused a change in the sessile invertebrate assemblages. Cage controls were partial cages constructed from both 2 mm and 10 mm mesh. The results indicated that didemnid ascidians may have been preyed upon by a small predator, but this predator was not identified. However, predation did not exert a strong influence on other taxa or on the overall structure of sessile invertebrate communities at Queenscliff.Lineage
Maintenance and Update Frequency: notPlanned
Statement: Roughened black Perspex plates (110 x 110 x 15 mm) were used to establish sessile invertebrate assemblages. Square cages (130 mm x 130 mm x 150 mm height) were constructed using either 10 mm mesh plastic Gutter Guard TM or 2 mm mesh flyscreen. Unlike the Gutter Guard TM, the flyscreen was not rigid so an internal frame was built with the Gutter Guard TM which was then completely covered with the 2 mm mesh flyscreen. Partial cages had half of the roof and half of two side walls removed to allow predators access to plates whilst leaving as much of the cage intact as possible. Species identification and counts were made using a binocular dissecting microscope.
Statement: This dataset gives the abundances of sessile invertebrates on plates deployed at Queenscliff Pier, Queenscliff, Victoria. Abundances are given after the initial four day settlement period and 20 and 40 days after these initial assemblages were exposure to five predation exclusion treatments: i) no cage, no exclusion of predators; ii) full 2 mm mesh cage, total exclusion of predators; iii) full 10 mm mesh cage, exclusion of large predators only; iv) partial 2 mm mesh cage, cage control; v); partial 10 mm mesh cage, cage control. The cage control treatments were established to identify if the cages themselves caused a change in the sessile invertebrate assemblages. Studies were carried out between early February and mid March 2006.
Sessile invertebrate assemblages were established on thirty six Perspex plates attached to a sea wall under the Queenscliff Pier. Individual plates were separated by 150 mm and arranged in a 6 x 6 array at depths between 1 and 3 m at low tide. After four days, six plates were removed to assess the initial assemblage and the remaining plates were randomly allocated to the five predation exclusion treatments. Each of the five treatments was applied to six replicate plates. The experiment was repeated twice, exposing plates to the experimental treatment for either 20 or 40 days. At the end of each experiment the plates were retrieved and immediately sealed and returned to the laboratory for identification and enumeration of sessile invertebrates and mobile animals using a binocular dissecting microscope. The number of individuals on the entire plate was counted, excluding the 5 mm perimeter of the plate.
The data columns in the dataset are: Pylon (1-14); Depth (1, 2, 3 m); Treatment (UC, uncaged; C2, 2 mm mesh full cage; C10, 10 mm mesh full cage, PC2, 2 mm mesh partial cage; PC10, 10 mm mesh partial cage control; Duration (Initial, 20, 40). The remaining columns give the number of individuals per plate for each identified taxa.
Note that this dataset includes rare taxa not analysed in the associated publication (Sams and Keough, 2007).
For more details on the methods and experimental design see
Sams, M.A and Keough, M.J. (2007) Predation during early post settlement varies in importance for shaping marine sessile invertebrate communities, Marine Ecology Progress Series (in press).
Sams, M.A. Predation during early post settlement: an important process shaping marine sessile communities? HonoursThesis, University of Melbourne
b. Scale: counts are express as either the number of individuals per plate (100 mm2) or as percentage cover
c. Media Types: Not Relevant
d. Date: Feb-March 2006
e. Dates of various parts of the process: See above
2. Processing Steps:
a. Intermediate processing steps (after data capture): see collectionHardware
b. Methods used to generate final product: Not Relevant
Notes
CreditParks Victoria gave permission to use Queenscliff Pier, Queenscliff. Various people provided assisted in the field including A. O' Brien, K. Blackman, D. Semmens, E. Bone and E. Broughton, and B. Loughman provided assistance in the laboratory.
Purpose
To assess if the effects of predation on recently settled sessile invertebrate assemblages at Queenscliff, Victoria
To assess if the effects of predation on recently settled sessile invertebrate assemblages at Queenscliff, Victoria
Created: 14 03 2007
Data time period: 2006-02-01 to 2006-03-31
text: westlimit=144.66794; southlimit=-38.26794; eastlimit=144.66794; northlimit=-38.26794
text: uplimit=1; downlimit=1
Subjects
20 000000 |
22 085000 |
35 000000 |
35 013000 |
Ascidiacea |
BIOSPHERE |
Biosphere | Ecological Dynamics | Predation |
Bryozoa |
COMMUNITY DYNAMICS |
Community Structure |
Didemnidae |
EARTH SCIENCE |
ECOLOGICAL DYNAMICS |
Oceans | Marine Biology | Marine Invertebrates |
Species Recruitment |
Serpulidae |
biota |
depth |
duration |
experimental_treatment |
pylon |
taxonomic_group_count |
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Other Information
Identifiers
- global : 5d3d05b0-189b-11dc-a8fb-00188b4c0af8
