List of Titles

Size and quantity of woody debris affects fish assemblages in a sediment-disturbed lowland river

- Howson, Travis, Robson, Belinda, Matthews, Ty, Mitchell, Bradley

Authors: Howson, Travis , Robson, Belinda , Matthews, Ty , Mitchell, Bradley
Date: 2012
Type: Text , Journal article
Relation: Ecological Engineering Vol. 40, no. (2012), p. 144-152
Full Text: false
Reviewed:
Description: Responses by fish assemblages to individual restoration actions among a suite of channel modifications are not well understood. We investigated whether increasing woody debris abundance, without significant change to channel morphology, would increase native fish abundance and species richness in a sediment-disturbed river channel (Glenelg River, Victoria, Australia). We conducted a Before-After, Control-Impact design experiment at twelve locations containing either a high (n=6) or low (n=6) quantity of large woody debris (LWD). We added small woody debris (SWD) to half (n=6: 3 high, 3 low LWD densities) of the locations to increase woody debris complexity without the impacts on channel morphology associated with LWD manipulations. Fish species richness and abundance was quantified using electrofishing surveys before (4 sampling trips) and after (3 sampling trips) SWD addition. Fish species richness was not associated with high or low quantities of LWD or with types of woody debris (LWD or SWD). Addition of SWD altered fish assemblage composition but the effect depended on LWD quantity. SWD additions to locations with low LWD quantities increased abundance of two, wood-affiliated species: Philypnodon grandiceps and Gadopsis marmoratus. SWD additions to locations with high LWD quantities increased abundance of P. grandiceps and Galaxias olidus. Fish body size was important in detecting a response to added SWD because for two species, only certain size classes responded: adults of P. grandiceps (>50. mm TL) and juveniles of G. marmoratus (<123. mm TL). Fish assemblages responded positively to increased density of SWD through local increases in abundance, despite channel sedimentation. Unlike LWD, SWD is relatively cheap to place in rivers because it does not require heavy machinery and can be obtained without tree mortality. The use of SWD to assist in habitat restoration, especially for small species of native fish and juvenile fish, should be considered as a strategy in river restoration. Â© 2012.

The Current Status Of Different Age, Direct-Seeded Revegetation Sites In An Agricultural Landscape In The Burrumbeet Region, Victoria, Australia

- Florentine, Singarayer, Graz, Patrick, Ambrose, Graeme, O'Brien, L.

Authors: Florentine, Singarayer , Graz, Patrick , Ambrose, Graeme , O'Brien, L.
Date: 2013
Type: Text , Journal article
Relation: Land Degradation and Development Vol. 24, no. 1 (2013), p. 81-89
Full Text: false
Reviewed:
Description: Many vegetation restoration works have been undertaken in Australia but only a few of those projects have been assessed for effectiveness. Revisiting earlier restoration attempts and analysing data from them is fundamental to the development of evidence-based prescriptions for future restoration work. Therefore, this study's objectives were to (I) compare plant species composition of different age direct-seeded revegetated sites and (II) determine the effect, if any, of different ages of revegetated sites on the natural recruitment of native plants. The study investigated four fenced restoration sites, dating from 2000, 2001, 2004 and 2005. Results showed that the density of plants surviving varied widely between plots of different ages. The highest density was found in the 2001 plot (2195Â·.7 stemsha-1), followed by 2000 (1877Â·8 stemsha-1), 2004 (197Â·6 stemsha-1) and 2005 (195Â·4 stemsha-1). An ANOVA showed that the overall amount of seed broadcast does not play a significant (p=0Â·437) role in the establishment rate. Overall, Eucalyptus ovata was found to be dominant in the 2000 (794Â·4ha-1) and 2001 (971ha-1) sites. In contrast, Eucalyptus camaldulensis and Eucalyptus viminalis densities were highest in the 2004 (41ha-1) and 2005 (60Â·4ha-1) sites, respectively. PERMANOVA showed highly significant differences in the present plant composition between plots (p<0Â·0001), despite similar species mixes used in sowing. Recruitment was not found in any of the sites. The least weed cover and the highest litter cover were found in the 2001 plot. A similar trend was found in the 2000 plot. In contrast, high weed cover and low litter cover were found in the 2004 and 2005 plots. Since one of the major impediments to developing better restoration strategies is the inadequate documentation of past practices, studies such as these may shed some light on how the direct-seeded technique operates in a farm situation. © 2011 John Wiley & Sons, Ltd.

An outcome-based model for predicting recovery pathways in restored ecosystems : The Recovery Cascade Model

- Robson, Belinda, Mitchell, Bradley, Chester, Edwin

Authors: Robson, Belinda , Mitchell, Bradley , Chester, Edwin
Date: 2011
Type: Text , Journal article
Relation: Ecological Engineering Vol. 37, no. 9 (2011), p. 1379-1386
Full Text: false
Reviewed:
Description: Restoration is increasingly the focus of ecosystem management. Few conceptual models exist for predicting the consequences of restoration, especially those that predict the stages of recovery following restoration. Existing models focus either on defining endpoints for recovery or on defining ecosystem processes, but often do not identify barriers to recovery or potential negative effects of restoration. We describe a conceptual model that identifies the outcomes of the recovery pathways following flow restoration in rivers: the Recovery Cascade Model. The model identifies six general aspects of recovery following restoration: physical ecosystem change; creation of, or improvement in habitat condition; reconnection of the restored area to adjacent ecosystems; recolonization of the restored area; resumption of ecological processes; re-establishment of biotic interactions and reproduction by colonists in the restored area. These aspects may occur in sequence, such that recovery is blocked by a single barrier. The model accommodates feedback loops and includes strong connections between physical processes and ecosystem processes, but also identifies factors that are important in achieving endpoints such as potential barriers to further recovery. Identification of barriers to recovery enables improved planning to maximise the positive effects of restoration. By focussing on outcomes, the model provides a planning tool for managers that can be adapted for different ecosystems and restoration methods and which can be used to identify the amenities that an ecosystem will deliver at different stages of recovery. Ecosystem recovery is as much about overcoming barriers as it is about restorative actions. Â© 2011 Elsevier B.V.

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