The effects of temporal variability of disturbance on marine fouling communities.

Otto, Saskia (2005) The effects of temporal variability of disturbance on marine fouling communities. (Diploma thesis), Humboldt-Universität zu Berlin, Berlin, Germany, 72 pp.

[img] Text
Saskia_Otto.pdf - Published Version
Restricted to Registered users only

Download (4061Kb) | Contact

Abstract

Natural heterogeneity in ecological parameters, like population abundance, is widely recognized
and investigated, while variability in the processes that control these parameters has been
underappreciated. Experimental ecologists have focused mainly on the mean intensity of
predictor variables and ignored the potential of manipulating levels of variance as a treatment,
which ought to be considered explicitly in experimental designs to explore linkages between
process and pattern.
To understand the extent to which the diversity and structure of marine fouling
assemblages are influenced by a temporally variable disturbance regime, I conducted a field
experiment at two sites at the north-east coast of New Zealand from September 2004 to April
2005. PVC-settlement panels, grouped in blocks, were submerged for 3 months to allow for
colonization before the disturbance treatment started. Within an experimental duration of 150
days the communities on the panels were disturbed 10 times, while the intensity, the size of
disturbed area and the frequency of disturbance events were kept constant. Two levels of
temporal variability were defined by the deviation of the lengths of time intervals between
disturbance events from the mean time interval, i.e. 15 days. A disturbance regime with constant
time intervals of 15 days between disturbance events served as a control. Additionally, different
sequences of time intervals were nested in the two levels of variability. Undisturbed settlement
panels provided reference communities.
Species density, evenness and abundances were analysed by a univariate analysis of
variance (ANOVA), community composition and structure by the multivariate analysis of
similarities (ANOSIM). Contrarily to expectations of increasing diversity and heterogeneity of
communities with increasing variability and of differences among communities that
experienced different sequences, no consistent effect of variability and sequence on the fouling
communities was observed. Disturbance only affected species abundances but not diversity. The
results of this study were confirmed by the outcomes of 6 identical, concomitant experiments
carried out in three different regions on the southern hemisphere. Possible explanations for the
absence of effects, implications of this finding, advantages and disadvantages of this novel
experimental approach are discussed

Document Type: Thesis (Diploma thesis)
Thesis Advisors: UNSPECIFIED
Keywords: Benthic Ecology; GAME; marine fouling
Research affiliation: OceanRep > GEOMAR > FB3 Marine Ecology > FB3-EOE-B Experimental Ecology - Benthic Ecology
Open Access Journal?: No
Projects: GAME
Date Deposited: 08 Sep 2011 11:28
Last Modified: 06 Jul 2012 15:00
URI: http://oceanrep.geomar.de/id/eprint/12095

Actions (login required)

View Item View Item

Document Downloads

More statistics for this item...