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THE MAINTENANCE OF EXOTIC REEDS AT THE ONRUS RIVER ESTUARY

Posted on the 2nd December 2019

Comments on your documents on “WATERCOURSE REHABILITATION AND MANAGEMENT PLAN FOR THE PROPOSED REED MAINTENANCE ACTIVITIES, NEAR HERMANUS, WESTERN CAPE PROVINCE”
NOTIFICATION OF PUBLIC PARTICIPATION PERIOD: 31 October 2019 – 6 December 2019
GNEC Code: 50348
2 December 2019. 

Dear Mr Opperman,
This refers to our discussions on the matter and we comment only from an avian perspective. Our comments refer to bird species abundance on the estuary, the importance of birding tourism to the area and bird-watching in general. We also comment briefly on certain aspects described in the two documents that had been studied extensively. The clearing process of the alien reeds is supported in principle given the conditions that we describe. 

1. BIRD SPECIES ABUNDANCE ON THE ONRUS RIVER ESTUARY
Over the years concerns have been expressed about the dramatic increase of alien reeds at the estuary. This gradually reduced the area of surface water and more particularly available foraging space for wading birds. This had a negative impact on bird species abundance and to a lesser extent the importance of bird-watching opportunities along the estuary as this memorandum will show.

We have been involved in bird-watching around the Onrus River estuary and mouth area the over last two decades. This includes informal birding, taking visitors and birding groups on outings, as well as more formal surveys such as SABAP2 counts (the second SA Bird Atlas Project), CWAC counts (Coordinated Water Bird Counts) and BIRP counts (Birds in Reserves Project). The results of many of these surveys had been logged at the research facilities at UCT. We had analised the results of these surveys, together with a variety of reports on birding trips to the area for the purpose of these comments.

The BIRP spreadsheet gives an overview of species recorded at the estuary over the years. This list is available from us. The numbers used are as follows: 1= Common species that are mostly recorded in and around the estuary throughout the year. 2 = Species that had been recorded in the past, but not over the last four years. These include a few genuinely vagrant species that had only been recorded once. 3 = Species that are mostly water associated and are still present. 9 = Summer migrants. 

SPECIES NOT RECORDED DURING SURVEYS ON THE ONRUS ESTUARY OVER THE LAST FOUR YEARS
1. Pied Avocet
2. Acacia Pied Barbet
3. Yellow Bishop
4. Forest Buzzard
5. Cape Cormorant
6. Black Crake
7. Blue Crane
8. Maccoa Duck
9. White-faced Duck
10. Little Egret
11. Yellow-billed Egret
12. African Fish Eagle
13. Greater Flamingo
14. Red-chested Flufftail
15. Bar-tailed Godwit
16. Spur-winged Goose
17. Black-necked Grebe
18. Great Crested Grebe
19. Common Greenshank
20. Grey-headed Gull
21. Hamerkop
22. Greater Honeyguide
23. Lesser Honeyguide
24. Glossy Ibis
25. Black-winged Kite
26. Mallard
27. African Marsh Harrier
28. Banded Martin
29. Brown-throated Martin
30. Southern Masked Weaver
31. Fiery-necked Nightjar
32. African Olive Pigeon
33. Common Ringed Plover
34. Grey Plover
35. Kittlitz’s Plover
36. Three-banded Plover
37. Southern Pochard
38. African Rail
39. Ruff
40. Common Sandpiper
41. Curlew Sandpiper
42. Marsh Sandpiper
43. Cape Shoveler
44. African Snipe
45. Southern Grey-headed Sparrow
46. African Spoonbill
47. Wattled Starling
48. Little Stint
49. Cape Teal
50. Red-billed Teal
51. Caspian Tern
52. Ruddy Turnstone
53. Olive Woodpecker

VAGRANT SPECIES RECORDED ON THE ONRUS ESTUARY IN THE PAST
1. White-fronted Bee-eater
2. Little Blue Heron
3. Gull-billed Tern
4. Red-tailed Tropicbird
5. Sedge Warbler

A total of 171 species had been recorded at the Onrus River estuary over the last 20 years. Of these an astonishing 53 species had not been found over the last four years. A closer examination of this list indicates that the vast majority of these species either forage and feed on open water, or utilise shallows for this purpose. There can therefore be little doubt that the reduction of open surface water and foraging space due to the increase in reeds had a dramatic negative impact on species abundance and numbers at the estuary. This has a direct negative impact on bird-watching opportunities in the region in general and the estuary in particular as is being discussed in the next section.

2. A BRIEF DISCUSSION ON THE IMPLICATION FOR BIRDING TOURISM
Birding tourism (tourism aimed at experiencing birds in their natural habitat) is internationally regarded as the fastest growing eco-tourism segment. The Western Cape Province of South Africa is internationally renowned as a birding tourism destination and members of BirdLife Overberg had been involved in the marketing of the province for this purpose. A website (www.westerncapebirding.co.za) is updated with information continually and supported through social media postings. The Overstrand local municipal area is of particular importance in this regard as can be seen at the bird finder web page at this link:
http://www.westerncapebirding.co.za/overberg/routes.php?id=16

I had further done the research and drafted the motivations to have the region declared as an Important Bird and Biodiversity Area (IBA) with BirdLife International. This agency has stringent standards to protect these IBA’s across the globe. The Onrus River estuary featured very prominently in the supporting documentation to BLI. This situation has sadly changed dramatically in recent years. It is nearly impossible to do bird-watching at the estuary at this stage due to the rank and very high reeds. In the past there had been a bird hide on the eastern side of the estuary that was very popular with birders. This allowed for excellent bird photography of birds wading and feeding in the shallows. This hide is unfortunately no more and area where the hide used to be is now covered with reeds that probably have a width of 20 meters.

This problem is best illustrated with CWAC counts from the past. In 2010 a count produced 218 birds representing 29 species. The most recent quarterly CWAC count on Saturday 9 November 2019 only produced 18 birds representing 5 species. We are currently updating the Overstrand bird finder web page and are seriously considering deleting the estuary from it as bird-watching conditions had deteriorated so badly that it is most likely not worth the mention. From a conservation perspective one could also discuss the impact of the reeds on bird species diversity in the region, but this is not done here as it is fairly obvious.

The information discussed above should clearly indicate that from a birding perspective the proposal on the removal of the alien reeds need to be strongly supported and we do so. We do however point out a few issues that need to be considered when this decision is taken.

3. THE TIMING OF THE CLEARING OF THE REEDS

The majority of bird species utilising the area breed in spring and early summer. The clearing of reeds at this time will be totally inappropriate. The proposal in the documentation that the clearing should occur during the dry season towards the end of summer is supported for two reasons: Very few bird species breed at this time and the potential negative impact of heavy machinery will largely be mitigated when compared to the rainy season in winter.

4. THE MANAGEMENT OPTIONS BEING CONSIDERED

We refer to the management options summarised in the documentation: “Management options that are available include cutting of reeds by means of a mechanical reed cutter, with potential follow up treatment using the application of herbicide, and dredging, which entails the removal of sediment and reeds through the use of a dredge. The recommended reed control measures are described in detail in the Maintenance Management Plan and Ecological Assessment. As both these methods entails (sic) the stockpiling of reeds after removal, these reeds may not be burned on site due to the surrounding urbanised areas and the seeds may disperse and/or the plants may re-establish in these areas. Cut reeds may be stockpiled in a designated area to allow the reeds to dry out and be compacted for eventual transport, outside the delineated boundary of the watercourse, where after it will be removed to a registered disposal facility.”

These options seem fairly sound, but it needs to be ensured (and entrenched in the contract) that contractors stick to the prescribed rules to guarantee minimal environmental impacts. Clauses prescribing minimum fines for non adherence need to be built into the contract. This should apply to the use of mechanical reed cutters, the application of herbicides, dredging and the stockpiling and eventual removal of the cut reeds.

5. CONCLUDING COMMENTS

It is understandable that there are various other issues besides birds and birding that need to be considered before a decision is taken about the removal of alien reeds from the Onrus River estuary. We are certainly not qualified to comment on any of these. From bird-watching and birding tourism perspective there can however be little doubt that the alien reeds have a very detrimental impact on the estuary and we therefore support the removal thereof given the conditions described briefly.

Kindly note that we are prepared to do further representation in this regard and even do an illustrating site visit with the consultants if this is required. Further correspondence in this regard could be forwarded to the below. Also confirm in writing that the contents of this memorandum had been studied and that it will be incorporated into the decision making process.

Sincerely.

Anton Odendal

Dr. Anton Odendal
BirdLife Overberg
Manager: CleanMarine campaign
Manager: www.westerncapebirding.co.za
Email: birding@overberg.co.za
(c): +27 82 550 3347

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