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Monthly Archives: October 2014

A Volunteering Opportunity at a South Australian Project

The Upper Torrens Land Management Project (UTLMP) Grassy Groundcover Restoration Project is looking for volunteers to help with the project, especially at the Barossa Bushgardens. You can help out in the Seed Production Area (SPA) by doing planting and seed collecting and by helping out in the foam box nursery.

You can volunteer for Mondays, Wednesdays and/or Fridays at or around Mount Pleasant, or at the Barossa Bushgardens SPA at Nuriootpa on Tuesdays and Thursdays.

For more information please call Andrew Fairney on 0477 307 577, or the UTLMP office in the Mount Pleasant Natural Resource Centre on 8568 1876.

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Posted by on October 4, 2014 in Native grass restoration

 

S.A. Biodiversity Patches Ensure the Survival of Groundcover Plants in the Hills

From Greening Australia’s Grassy Groundcover Gazette, January, 2014. Reprinted with permission.

In the last edition of South Australia’s magazine The Green Australian, we highlighted the GGRP in Victoria (Ed: see previous article) for setting a benchmark in the revegetation of degraded landscapes. Using the Grassy Groundcover Restoration Project’s award-winning and ground-breaking techniques, SA Water has commenced their own project with the support of the GA’s South Australian nursery.

The S.A. Biodiversity Patches project focuses on establishing 55 colonies of understorey species within the SA Water Clarendon revegetation site. The site will ultimately contain a richness of species diversity that is not seen in previous revegetation sites, thus ensuring the continued survival of understorey and groundcover communities of the Adelaide Hills. Revegetation projects in cleared agricultural lands have traditionally focused on the establishment of only trees and shrubs, so largely avoiding the difficult task of establishing grass and herbaceous plants.

“…the colonies will provide an adequate seed source for the recruitment of understorey species. Species have been selected to ensure that there will be full representation of ‘plant trait groups’, so as to enable the new vegetation system to emulate the ecological function of remnant vegetation communities”, SA Water’s Shaun Kennedy said.

Seedling production is currently underway at the Greening Australia Nursery in Pasadena. The techniques used will secure supplies of high quality seed from a broad range of herbaceous species. Planting is scheduled to commence this month (Ed: January 2014?)

 
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Posted by on October 4, 2014 in Native grass restoration

 

What is Going on Below the Surface in our Restored Grasslands?

Dr Paul Gibson-Roy

From Greening Australia’s Grassy Groundcover Gazette, January, 2014. Reprinted with permission.

The following piece is a summary of a paper that is soon to appear in the Journal Ecological Management and Restoration. The work was commenced prior to the GGRP as part of my PhD, but continued as we established GGRP sites. The AMF work was supervised by the late Dr Cassandra McLean, who was an inspirational lecturer during my undergraduate years, a generous supervisor and supportive colleague in later years.

Arbuscular Mycorrhizal fungi (AMF) (Editor’s note: Arbuscules are sac-like structures that are associated with endomycorrhizae and which penetrate into plant cells.) are root-borne symbionts which are thought to be associated with up to 80% of all vascular plant species. The primary benefit to a plant of an AMF relationship relates of assisted uptake of water and nutrients, improved drought- and disease-tolerance. Therefore, functioning AMF are important because they increase the capacity of the plant to compete for resources in often harsh environments.

In terms of native restoration, experience from the sector has shown that high soil nutrients (from fertilisation) and soil seed banks that are dominated by weeds often leads to poor, or in the worst cases, nil establishment of planted or seeded native species and an associated invasion and dominance of weed species. For this reason, the GGRP tested scalping and long fallowing (using herbicides) to determine if they increased the success of native species sowings. However, during this period, some raised concerns that both techniques are drastic (for various reasons), and may even disrupt beneficial AMF. Bearing in mind the plant-derived benefits of AM relationships, we thought it important to investigate if this was the case.

Therefore, over several years, we tested plant roots in GGRP sites (following a minimum of 18 months growth) and remnant sites of see if they hosted AMF. We sampled 18 native (Arthropodium strictum, Astrostipa bigeniculata, Astrostipa mollis, Astrostipa scabra, Calocephalus citreus, Calocephalus lacteus, Chloris truncata, Chrysocephalum apiculatum, Chrysocephalum semipapposum, Kennedia prostrata, Leptorhynchos squamatus, Poa labillardieri, Rytidosperma caespitosa, Rytidosperma recompose, Rytidosperma setacea, Themeda triandra, Triptodiscus pygmaeus and Xerochrysum bracteantha ) and three exotics (Hypochoeris radicata, Lolium perenne and Phalaris aquatica) species across a broad geographical range of central and south-western Victoria during periods of active plant growth (spring and autumn). Root core were taken from a minimum of 20 plants of each species (at each site and site history – fallowed or scalped).

Roots were cleared and stained at Burnley, and examined under a compound light microscope for the presence/absence of structures that indicate functional AMF (aseptate external and internal hyphae, arbuscules and vesicles (see below)) and for percentage root colonisation. We then compared differences in percentage root colonisation for each species. They were sampled from more than one location and/or site-preparation history. We found AMF structures on all 18 native and three exotic species, regardless of whether they came from remnant or GGRP sites, or whether the GGRP sites had been fallowed or scalped prior to seeding. Only Themeda showed a significant statistical difference in % root colonisation between different locations (with two of three remnant grasslands exhibiting significantly higher colonisation than one other remnant and both GGRP sites). All the other species displayed varying root colonisation patterns between and within species and sites, with three (Chloris truncata, Poa labillardieri and Themeda triandra) exhibiting very high percentage colonisation (>80%) from one or more sites, while others exhibited colonisation percentages across the medium (11 – 49%) to high (50 – 79%) ranges.

Our findings seem to indicate that, firstly, AMF are ubiquitous in the herbaceous flora of this region (in both native and exotic herbaceous vegetation) and secondly, they were present in our GGRP sites even though these had undergone what are considered as intensive, disruptive site preparation methods. It also suggests that, while these site preparation methods had a marked impact on the vegetation structure (as our plant monitoring has shown), they have had little impact on eventual AMF colonisation.

So how did the fungi get to these sites? It seems likely that hyphal and/or spore loads or infected root fragments that are present in the soils, or which had moved onto the sites following seeding (possibly through wind, water, soil of animal movement) had provided the inoculum for colonising the seeded communities. Based on these observations, it is also likely that AM will colonise following soil disturbance from other environmental events such as fires or floods, or when vegetation is re-established following disturbances such as road works.

Our examination also revealed that the three common weed species (Hypochoeris radicata, Lolium perenne and Phalaris aquatica) each hosted AMF. Each is common in pastures, roadsides and, sadly, within native remnant where they (especially the Phalaris) tend to dominate. That they host AMF suggests that each derives a competitive advantage from the association and, along with any co-occurring mycorrhizal species (native or exotic), must form part of a larger inter-specific flow of resources in the community.

Summary

What is happening below the ground at our GGRP sites? Undoubtedly a lot; but in regard to AM relations, our examination of AMF in both GGRP and remnant sites indicates that:

  • AMF are common in the herbaceous flora of the region (native and exotic);

  • There was little difference in the AMF colonisation characteristics between remnant and restored sites;

  • That AMF colonised GGRP communities to a similar extent regardless of the original site preparation technique (fallowing or scalping).

While it is thought that the two site preparation techniques employed by the GGRP are drastic and possibly detrimental to AMF relationships, this seems not to be the case (at least by the time we surveyed). However, despite the finding that site preparation method did not adversely influence AMF characteristics, it was still only on scalped sites that our native grassland species dominated and persisted as diverse communities.

S.A. Biodiversity Patches Ensure the Survival of Groundcover Plants in the Hills

From Greening Australia’s Grassy Groundcover Gazette, January, 2014. Reprinted with permission.

In the last edition of South Australia’s magazine The Green Australian, we highlighted the GGRP in Victoria (Ed: see previous article) for setting a benchmark in the revegetation of degraded landscapes. Using the Grassy Groundcover Restoration Project’s award-winning and ground-breaking techniques, SA Water has commenced their own project with the support of the GA’s South Australian nursery.

The S.A. Biodiversity Patches project focuses on establishing 55 colonies of understorey species within the SA Water Clarendon revegetation site. The site will ultimately contain a richness of species diversity that is not seen in previous revegetation sites, thus ensuring the continued survival of understorey and groundcover communities of the Adelaide Hills. Revegetation projects in cleared agricultural lands have traditionally focused on the establishment of only trees and shrubs, so largely avoiding the difficult task of establishing grass and herbaceous plants.

“…the colonies will provide an adequate seed source for the recruitment of understorey species. Species have been selected to ensure that there will be full representation of ‘plant trait groups’, so as to enable the new vegetation system to emulate the ecological function of remnant vegetation communities”, SA Water’s Shaun Kennedy said.

Seedling production is currently underway at the Greening Australia Nursery in Pasadena. The techniques used will secure supplies of high quality seed from a broad range of herbaceous species. Planting is scheduled to commence this month (Ed: January 2014?)

 
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Posted by on October 4, 2014 in Soil/grass synergies