LMP Report 2010/10

 

Liesbeek Maintenance Project Report

 

October 2010

 

By: James Cooper (Project Manager)

 

 

The River Team

For the first two weeks of October the team worked 5 days a week. The first two Tuesdays of the month were spent on the Purple Loosestrife project (refer to Purple Loosestrife section) and Fridays were spent cleaning the banks of the river in Obsevatory. SANBI, Early Detection and Rapid Response, funded Tuesdays work and Fridays work was subsidised by the Grant in aid funding. The remaining days were funded by SAB and Tuffy brands.

From the 25 October 2010 Ntobeko Dyani officially took over the supervisor role of the team. He has been with the project for two months and has a good understanding of the general maintenance activities that need to be completed on the Liesbeek and is currently drawing up a management plan with the project manager which will specify goals and time lines for any other projects the team undertake. Ntobeko has been collecting data on a daily basis on the Maintenance Teams activities. This includes the number of bags used, time spent on each activity, number of staff present, tools and equipment used and any other findings. This will help establish time lines for the different activities and projects that are completed on the Liesbeek and will contribute to the management plan.

The team are due to sign their new three month contracts on the 1 November 2010. The project manager will be doing the second staff evaluations with each team member on the 1 November 2010 before they sign their new contracts. This will asses whether the staff have improved in areas that were identified as potential problem areas in the last evaluation and enable the project manager to determine whether they have met the goals that were set with each individual. Ntobeko will be present during these evaluations to get an understanding of the procedure and will give valuable input on staff members in the future.

   

 

 

 

 

 

 

 

 

 

 

 

Work

Projects

 

Removal of Parrots Feather in Liesbeek Lake

The team continued the manual removal the Parrots feather in Liesbeek Lake for the first week in October 2010. The clearing was put on hold by the City of Cape Town, Biodiversity branch, after the project manager had discovered that the City Invasive Alien Species Unit (IAS) had just obtained a bio-control agent for the species.

The project manager met with Chandre Rhoda (head of the aquatic IAS programme) from the IAS unit on site to look at potentially releasing the bio-control agent into Liesbeek Lake, saving the project much time and resources. The bio-control agent is a weevil that feeds on plants that are growing above the surface of the water, eventually killing the entire plant. Unfortunately most of the Parrots Feather in Liesbeek Lake grows submerged in the water. There is another bio-control agent for these submerged plants but the IAS unit has yet to obtain any specimens.

The weevil will be released into Liesbeek Lake to combat the above surface plants next month (the IAS is still breeding sufficient numbers) and the team continue with the labour intensive manual removal. We have had success with our trap (fig. 1) that we have constructed to remove large amounts of the Parrots Feather. Mr Robert Gimburg joined the team for a day of removal and has given the project manager some ideas on how to improve the trap design.

Figure 1: The Parrots Feather trap

           

Weekly cleanups in Observatory

The team continue with the clean every Friday in Observatory. There has already been a huge improvement after a month worth of Friday cleans in this area. The first clean we undertook in this area on the 10 September saw the team collect 15 bags of rubbish. This month the team collected seven, eight, three and five bags of litter respectively for each week of the month.

 

Purple Loosetrife Project

The team began follow-up work on Purple Loosestrife this month. The project has been able to secure funding from SANBI for follow-up work on Loosestrife for one day of the week, namely Tuesdays. The team spent the first two Tuesdays of the month removing all the Fragmites reeds (fig. 2) around the large stand of Loosestrife that was cleared in Observatory (Liesbeek Lake) earlier in the year. Just from initial observations it appears that our clearing and application of herbicide has been ineffective.  We have not yet checked our permanent monitoring points as the reeds had to be cleared first before we could accurately look at these plots.

Unfortunately the monitoring of the plots, potential research into the clearing method and clearing of Loosestrife has been put on hold until all the parties involved (SANBI, City of Cape Town, Friends of the Liesbeek and other interested parties) have met and discussed the way forward. This meeting is due to take place on the 17 November 2010 and will be attended by the Maintenance Project manager.

Shaun du Plessis (conservation student) will have his research paper on the potential spread of Purple Loosestrife into new un-invaded areas completed by the 30 October 2010. He and the project manager have also completed a draft management plan of the species.

 

 

Figure 2: The team cutting away the reeds. Note all the green is Loosestrife

 

 

 

 

 

Removal of Duckweed in the Arboretum ponds

There are three ponds situated in the Arboretum, just below Kirstenbosch, that are fed by the Protea spring. These ponds have been invaded by a species of Duckweed that has covered the entire surface of two of the ponds (fig. 3).

 

 

Figure 3: One of the ponds with a hundred percent cover of Duckweed

During this month the Maintenance Team spent four days removing Duckweed from the first of these ponds. We used one of our litter traps to separate the pond into manageable sections (fig. 4), and secured it across the pond at the end of each day to ensure that the Duckweed couldn’t move back into the cleared section.

 

Figure 4: The litter trap separating the cleared from the invaded section.

 

Again the clearing process was extremely time consuming. The team went into the pond in waders and used nets to remove every piece of Duckweed (fig. 5). We had to ensure that this was done properly and found that we had to repeat some of the clearing in sections due to pieces of Duckweed being caught up in vegetation around the pond. The team have trimmed the vegetation around this pond and removed all visible Duckweed. We will be monitoring this pond over the next month to ensure that the clearing technique has worked or to see how long it will take for it to become overgrown again. If it has been a success we will clear the other invaded pond.

 

Figure 5: Ntobeko Dyani removes a net full of Duckweed

 

The project manager made an interesting observation that there was little or no Duckweed in the second pond. It is suspected that this could be due to the presence of certain diatoms or algae that is absent in the other two ponds, or chemical and nutrient differences in the water. Five samples were taken of the water and scrapings of diatoms from each pond. These samples have been sent to the UCT where they will be analysed and any differences will be noted. If we find that there are significant differences attempts could be made to introduce any missing diatoms or algae into the invaded ponds as a control measure for Duckweed.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Compiling a species list of the Liesbeek

At the beginning of the month the Maintenance Project manager met with Amy, an international student, who is conducting a study on the species diversity found along different stretches of the Liesbeek. Three sections of Liesbeek were identified as sites for her study. The first section is the relatively pristine upper section of the Liesbeek known as the Arboretum. The second section is the canalised; highly impacted section from Rondebosch to Mowbrey and the third is the non-canalised, highly invaded section between River Park and Observatory. The primary objective of the study is to find out more about relationships between fauna and flora species found in these different sections. This involves identifying the dominant plant species in each section and observing how these various plants are utilised by the fauna species found in the area. This research will give the Maintenance Project a better idea of which plant species to plant in order to attract a greater diversity of fauna species along the Liesbeek. The secondary objective of the study is to draw up a species list for the Liesbeek.

Amy will complete her research by the beginning of November and her results and conclusions will be included in the November report.    

 

 

Figure 6: Amy and Ntobeko getting ready to conduct part of her research.

 

 

 

 

 

 

 

 

General Maintenance

Litter clean ups

The team continued with weekly cleans from Newlands Swimming Pool to the siding in Rondebosch and cleaning the banks in Observatory and undertook the monthly cleans at Paradise Park, Riverside rd and River Park.

Weeding

The team has completed weeding all the flowerbeds from Roslyn Park in Rondebosch up to South African Breweries in Newlands. They have also weeded the site before Belmont Bridge.

 

Cleaning Alfred stream

There was no need to clean Alfred stream this month.

 

Path Maintenance

The team have been trimming the paths regularly in Rondebosch due to the sudden spring growth. We are concentrating on the area from Breweries to Riverside Mall.

Canal Maintenance

There has been no canal maintenance this month.

 

Alien vegetation removal

The team concentrated on removing Kikuyu grass and Nasturtiums from the rehabilitation site behind Newlands Swimming Pool on a weekly basis. The team also removed Balloon Vine, Moth catcher and Parrots Feather during daily activities.

 

Other City department activities

City Parks

James met with City parks regarding the railing which has been knocked down, presumably by a wayward car, on Boundary Rd. The repair of this railing has been factored into the ward allocation budget.

 

Roads and Storm water

Roads and storm water department continue to collect our Tuffy bags every Friday or Saturday at sites along the Liesbeek.

Displaced people Unit

The displaced people unit was not contacted this month. This is surprising as the vagrants usually move back to the Liesbeek and the beginning of spring. The project manager will continue to monitor the displaced people found on the river, identifying those areas usually used for temporary shelters and exercising preventative measures. These will include removing suitable vegetation for the establishment of shelters and making areas such as those found under bridges inaccessible to the vagrants.

 

 

 

 

 

 

 

Training

All team members have been involved with Amy’s research project and compiling of a species list this month. They accompanied Ntobeko and Amy on two occasions each and have learnt valuable information on the relationship between fauna and flora species along the river and what species are found in the different areas along the Liesbeek.

 

Website

The project manager has been unable to post any articles on the website this month. There have been some internet but time constraints have been the main reason behind this. Write ups from this and the previous report will be posted this next month.

Other

Meeting with John Raimondo

The project manager met with Mr John Raimondo, an interested resident in Bishops who has made a generous contribution to the Maintenance Project, regarding working more often in the upper reaches of the Liesbeek and rehabilitating it. This was an extremely positive meeting and both parties have agreed to raise awareness with the Bishops court residents about the Liesbeek and hopefully get them to contribute financially to the rehabilitation of this section. The project manager plans to give a presentation on past and current projects that the Maintenance team have completed along the lower sections of the Liesbeek and would like to get Mrs Joan Parker to give a presentation on her successful project tha is ongoing in the lower strech of Riverside Rd.

Interesting Sightings

Figure 7: Two little Egrets exposing food hidden amongst the Parrots Feather in Liesbeek Lake.

Figure 8: A Bul bul pruning himself in the Arboretum

Figure 9: A Pied Kingfisher readying himself for a dive to catch fish in Liesbeek Lake

Figure 10: An unidentified Dietes species in the Arboretum

Figure: The team with Amy in Observatory.

Figure: Our new team member, Liesebeth, found in the river in Observatory, this is what I call empowering the locals.

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