Hartbeespoort water birds in crisis

CWAC (Co-ordinated Water Bird Count) is one of the citizen science programmes of the University of Cape Town’s Animal Demographics Unit (ADU).

Five teams were in the field in North West covering the entire area from Xanadu in the east, to Magaliespark in the west, Kormorant reports. Two teams were on boats and the rest on foot.

To their shock, they discovered that water bird numbers had crashed from more than 11 860 during the 16 July 2016 winter count, which was the highest ever, to 3 462, which is the lowest since 2010 and the third worst count on the dam since counting started.

A number of species had collapsed from over 400 in July last year, to one during this count. The species in question was Little Grebe, who spends most of its life on or under water searching for food.

This can be explained firstly by the destruction of a large number of habitats by the large floating islands of water hyacinth that are multiplying at a rapid rate and covering large areas of the shore and banks, especially on the southern side of the Hartbeespoort Dam, taking away shallower water habitats for birds like Greater Flamingo, Pied Avocet, and Black-winged Stilt, to name just a few.

Mud flats on water edges are non-existent, thus taking away roosting and feeding habitats for most migrant waders, duck and goose species. Even the Red Knobbed Coot who feed on water hyacinth has crashed in numbers from an estimated 7 000 plus in July 2016, to 252 in the recent count.

Some of the changes can also be attributed to the heightened degree of pollution entering the dam, especially the major inflow of raw sewage during October 2016 from the Jukskei River, turning the Crocodile River black in colour and forming a distinct stripe across the dam as it was pushed towards the dam wall.

The satellite image from 23 December 2016 shows the extent of the hyacinth and algal bloom problem.

Drastic steps need to be taken to reduce the water hyacinth to manageable levels as it is not only impacting on the wildlife, but also local tourism, especially fishing.

A number of these issues were raised in Birdlife Hartbeespoort’s response to the new Resource Management Plan (RMP) inputs which closed at the end of January.

Other issues that is a major cause of the dramatic decline of birdlife in the area are the reduction of nutrients both from Madibeng’s continual leaking of sewage into the dam and the high levels of pollution coming down the Crocodile River.

On a positive note, where the floating islands built by Metsi a Me have stabilised and not sunk, they have formed great breeding sites for a number of the bird species, including Purple and Black-headed Herons.

Luckily the use of Nile Papyrus has contributed to the stability of the islands.

According to Birdlife Hartbeespoort the RMP needs to urgently address the above issues as well as clearly designate the different areas for recreational and conservation purposes so that future generations will still be able to enjoy the birds and wildlife of the Hartbeespoort Dam.

– Caxton News Service