TRANSPORT FOR CAPE TOWN ENVIRONMENTAL MANAGEMENT DEPARTMENT Koos Retief Biodiversity Area Manager: Milnerton T: 021 444 0315 E: [email protected] T A B L E B A Y N A T U R E R E S E R V E QUARTERLY REPORT APRIL – JUNE 2017 CONTENTS Pg. 1 EXECUTIVE SUMMARY ......................................... 2 2 HIGHLIGHTS & CHALLENGES ............................. 3 3 CONSERVATION PLANNING .............................. 4 4 FLORA .................................................................... 5 5 FAUNA ................................................................... 8 6 SOIL ........................................................................ 11 7 WATER ................................................................... 11 8 FIRE ......................................................................... 13 9 PEOPLE, TOURISM & EDUCATION ..................... 14 10 STAFF ...................................................................... 17 11 LAW ENFORCEMENT ........................................... 18 12 INFRASTRUCTURE & EQUIPMENT ........................ 20 APPENDIX A: MAP OF RESERVE ......................... 21 APPENDIX B: PRESS ARTICLES ............................. 22 The City of Cape Town’s Nature Reserves webpage can be accessed by clicking this link. City of Cape Town | Error! No text of specified style in document. 1 Table Bay Nature Reserve | Tafelbaai-natuurreservaat | ULondolozo lweNdalo lase-Table Bay 1 EXECUTIVE SUMMARY A blue-green algal bloom in Rietvlei resulted in the closure of the water since 17/03/2017. Income from visitors at the Rietvlei Water Area during this quarter was therefore the lowest ever recorded. The water was only opened to the public again on 30/06/2017. The new visitor tariffs for the 2017/18 financial year came into effect the next day on 1/07/2017. The daily entrance fees and environmental education fees at the Rietvlei Water Area remained unchanged for the new financial year. Two Cape grysbok surveys were conducted in Milnerton Racecourse, indicating that the grysbok numbers are as high as 30 animals there. Other fauna monitoring activities included camera traps at Milnerton Racecourse, small mammal trap arrays in the Milnerton Lagoon, and an integrated water bird census. A Protected Area and Management Effectiveness Tracking review was conducted for the Nature Reserve on 20/06/2017. The Protected Area Advisory Committee (PAAC) had its seventh meeting on 20/04/2017, which was attended by 24 representatives from 17 organisations. Alien and invasive plants that were cleared, including Port Jackson (Acacia saligna), Rooikrans (Acacia cyclops), Manatoka (Myoporum tenuifolium), Smooth prickly pear (Opuntia monocantha), Yucca species, Lavatera (Malva arborea), Spanish broom (Spartium junceum), Caster-oil plant (Ricinus communis), Spanish Giant reed (Arundo donax), Pampas grass (Cortaderia selloana), Red River gums (Eucalyptus camaldulensis), and Water Hyacinth (Eichhornia crassipes). The Custodians of Rare and Endangered Wildflowers (CREW) visited the Milnerton Racecourse on 26/04/2017 and the Coastal Section on 01/06/2017. CREW invited members of the staff and public to learn about identifying indigenous plants and monitoring threatened and endangered flora. The Milnerton Racecourse land swap restoration project started with the removal of compacted laterite gravel and the transfer of topsoil, mulch, seeds, and bulbs to the receptor site. Plant cuttings were taken from living plants in the Nature Reserve to propagate for later replanting into the restoration site. The dust control operation, that was intended to suppress dust emanating from the season pans, was stopped and all pipes and other materials were removed from the pans by 09/06/2017. Level 4 water restrictions were approved by the City of Cape Town. Rainfall remained below average for most of this quarter until June, when the measured rainfall at Rietvlei increased to above the average for that month. A very large storm hit the Western Cape on 7/06/2017, bringing with it significant rainfall, strong winds, and a very strong storm surge that pushed into the Milnerton Lagoon from the sea. A firebreak was constructed at the northern edge of the Coastal Section adjacent to the Dolphin Beach Hotel to prevent the possible spread of wildfires from the Nature Reserve onto the hotel property. Wildfires occurred in the Zoarvlei Section on 24/04/2017 and in the Diep River Section on 14/05/2017. The Nature Reserve facilities benefited 584 people over 24 event days. Environmental Education also generated 340 person days of benefit over ten event days. Training of permanent and temporary staff amounted to 24 person days over 11 training event days. Illegal overnight structures and displaced people were removed from various locations in the Nature Reserve, including the Coastal Section, Rietvlei Section, Zoarvlei Section and the Milnerton Lagoon. Other illegal activities included illegal footpaths, dumping of building rubble, littering, and illegal cattle grazing in the Diep River Section. Two site cleaning teams worked in the Zoarvlei Section to address the littering. Figure 1. A group photo of the Table Bay Nature Reserve team. CITY OF CAPE TOWN QUARTERLY REPORT – 1 JANUARY TO 31 MARCH 2017 2 Table Bay Nature Reserve | Tafelbaai-natuurreservaat | ULondolozo lweNdalo lase-Table Bay 2 HIGHLIGHTS & CHALLENGES 2.1 CHALLENGE: A blue-green algal bloom in the Rietvlei Water Area resulted in its closure since 17/03/2017. It remained closed for public safety reasons throughout this quarter. The water was only re- opened to the public again on 30/06/2017 after a consistent decline in the algae toxins was observed. The water was visibly green (sometimes almost opaque) and at certain times there were very toxic blue- green scum layers that formed on the shoreline. Samples from these scum layers (sample code: RTV21) were analysed, and the toxin levels were almost as high as 1600 micrograms of microcystin toxin per liter at times. This exceeded the World Health Organisation’s (WHO) guidelines for recreational water bodies by two orders of magnitude (see Figure 2 below). Apart from the scum samples, weekly water samples from the Milnerton Aquatic Club shoreline (sample code: MAC) and the Rietvlei jetty (sample code: RTV02) were analysed and graphs of the trends in the various parameters were maintained. The total count of blue-green algae (Cyanophyceae) cells as well as chlorophyll levels fluctuated throughout this quarter, but remained high. This indicated that blue-green algal bloom was persistent (see Figures 3 and 4). The most important parameter, however, was the microcystin toxins that are released from the algae cells. Results indicated a gradual and consistent decline in these toxins over a period of three months, even though some fluctuations were observed at times. The fluctuations could have been caused by variations in the ambient temperature, the amount of light exposure and light penetration into the water, as well as the effects of wind. Towards the end of the quarter it became clear that, despite there being high levels of algae in the water, the quality approached the standard of drinking water (1 microgram of microcystin toxin per liter) (see Figure 4 below). This justified the re-opening of the water to the public. 1800 450000 1600 400000 350000 1400 300000 1200 250000 1000 200000 800 150000 600 100000 400 50000 200 0 16-Mar-17 16-Apr-17 16-May-17 16-Jun-17 0 MAC Cyanophyceae 16-Mar-17 16-Apr-17 16-May-17 16-Jun-17 RTV02 Cyanophyceae RTV21 microcystins 10 micrograms/liter WHO moderate probability guideline Figure 2. Microcystin toxin levels from scum samples at Rietvlei Figure 3. Cyanophyceae (Blue-green) cell count from MAC shore and slipway (RTV21). Rietvlei jetty compared to WHO guidelines. 150 20 100 15 50 10 0 5 16-Mar-17 16-Apr-17 16-May-17 16-Jun-17 MAC Cholophyll-a 0 RTV02 Chlorophyll-a WHO moderate probability guideline 16-Mar-17 16-Apr-17 16-May-17 16-Jun-17 Recreational chronic limit MAC microcystins RTV02 microcystins WHO low probability guideline 10 micrograms/liter 1 microgram/liter Figure 4. Chlorophyll-a levels from MAC shore and Rietvlei jetty Figure 5. Microcystin toxin levels from MAC shore and Rietvlei jetty compared to WHO guidelines. compared to WHO guidelines. CITY OF CAPE TOWN QUARTERLY REPORT – 1 JANUARY TO 31 MARCH 2017 3 Table Bay Nature Reserve | Tafelbaai-natuurreservaat | ULondolozo lweNdalo lase-Table Bay 2.2 HIGHLIGHT: Two Cape grysbok surveys were conducted in the Milnerton Racecourse Section by contract reserve supervisor, Kyran Wright, on 26 and 28/06/2017 (see Figure 6 below). Kyran used Biodiversity Management Branch staff in order to determine whether a previous survey that was conducted by the former contract reserve supervisor, Landi Louw, and a team of public volunteers, was accurate. Some fauna specialists were of the opinion that Landi Louw’s survey over-estimated the amount of grysbok, due to the inexperience of the public volunteers. The results from Kyran’s survey however indicated that the grysbok numbers were indeed very high with perhaps even more animals than what Landi’s team counted. Figure 6. Biodiversity Management Branch staff conducted a drive-count census of Cape grysbok in the Milnerton Racecourse Section. 3 CONSERVATION PLANNING 3.1 Protected Area reviews and Management Effectiveness Tracking reviews of the North Region’s nature reserves were conducted on 20/06/2017. Table Bay Nature Reserve was one of the reserves assessed during the review, including also