We begin 2012 with bumper newsletter with a very interesting and informative article on alien vegetation by Jay Cowan. Jay organises the hacking groups in Silvermine. Thank you Jay.
Also included in this newsletter is shortened version of an article on Felicias which appeared in the December 2011 issue of Veld & Flora published by The Botanical Society of South Africa written by FOSNA members, Sheila Robinson, Corinne Merry, Frankie Shoosmith and Yvonne Viljoen,. We thank Veld & Flora for allowing us to use this article.
Nature News includes a Cape Batis nest, Otters at the Dam, Night of fireflies, and an update about the Silvermine Wetlands.
Enjoy the read. Happy hacking and hiking.
Each year we start our program with a Breakfast at Bertie’s Balcony in Silvermine. It entails a walk of approx an hour from the car park to the overhang. Each person carries part of the fair. While on the walk and at breakfast old friends unite and new ones are made. After the meal those who wish, go on a short walk. Many stay and chat while drinking more tea or coffee. Everyone is back at the cars at about noon.
Food and drinks are provided by the Friends (you pay your R35.00)
Bring your backpack, mug, plate, bowl, knife fork and spoon, hot water for your tea or coffee. Friends are welcome . Booking is essential as numbers are limited. Closing hour for booking is midday on the 25th Jan.
Henry, the car guard, took us to the far side of the dam to show us a Cape Batis nest. This small, neat bowl shaped nest was not easy to spot. Mrs Batis was sitting in it being fed by her mate! I passed by a few days later, sadly to find no nest and no birds. Maybe there was too much human traffic close by.
The Cape Batis has vey defined markings and is found mainly in moist forests and kloofs. They are active excitable little birds, usually found in pairs, feeding on spiders and insects found flying in the air among the trees. Breeding takes place from Sept- Dec. Two to three greenish or pink white eggs, with grey brown blotches are laid. The nest is woven with fibrous vegetation.
OTTERS AT THE DAM
Along the same path we came across an Otter latrine, with a large scat on the side of the path. It is good to know that otters are residing at the dam. Maybe now that the dogs are not allowed at the far side the otters feel safe. Early morning or evening would be the best time to see these beautiful shy creatures.
THE NIGHT OF THE FIREFLIES
The Sunset walk to Noordhoek Peak was not the best of evenings. The wind was most unpleasant and chilly. You had to be a devoted member to venture out. Everyone was kitted out in beanies, scarves, gloves and jackets. The sun set is always a special sight, with the big red ball sinking into the sea through layers of cloud. Then everyone waited for the green flash. That time the green lingered over the sea long enough for everyone to get a good look. (There are always those folk who never manage to see it). Once supper was finished and sun set we did not linger, we needed to get out of the cold and wind. We returned on the road towards the Noordhoek side of the mountain. Once off the top we were out of the cold and wind. While waiting to regroup and disrobing we noticed the bushes alongside were alive with fireflies. We then saw the whole mountain side was flickering with little lights. This amazing site continued all the way down to the dam.
Fireflies are also known as glow worms, they tend to be brown and soft bodied. The females in some species are similar in appearance to males. The most commonly known fireflies are nocturnal.
A female lays her fertilized eggs on or just below the surface of the ground. The eggs hatch 3-4 weeks later, and the larvae feed until the end of the summer. The larvae are commonly known as glow-worms. The term glow-worms also used for both adults and larvae of some species. Fireflies hibernate over winter during the larva stage; some do this by burrowing underground, or finding places under the bark of trees. They emerge in spring and after weeks of feeding; they pupate for about 2 weeks then emerge as adults. The larvae in most species feed on other larvae, snails or slugs. Light in adult beetles is now thought to be used in mate selection. They have evolved a variety of ways to communicate with mates in courtships: steady glow, flashing and the use of chemical signals unrelated to photic systems.
Shortly before the dam I took a tumble. I would like to thank everyone there for their kindness, compassion and patience in walking me back to the car. To those who pulled out torches to light the way, fearful that I should trip again. To the first-aider who kept me going with magic drops. The young man who so gently undid my backpack so as I could get into the car, then took charge to unlock and lock the gates. Those who drove my car and saw me safely home and made me a cup of tea, then the next morning went back to the gate to return the key for me. Then all the follow up phone calls to find out how I was. You are all special people. Thank you again.
Our bodies are wonderfully made and do repair themselves in TIME.
The wonder of all those fireflies will always remain fixed in my mind; it was truly a special evening.
Let us all make an extra effort in 2012 to keep our earth a healthy place. Have a wonderful year.
Evanne’s Wetland Update
Our big news was getting R25000 from the Rowland and Leta Hill Trust which has enabled us to get the new signage we have so desperately needed. The original name boards have succumbed to a combination of weather and vandals. With the Trust money we have ordered new Polywood signs. The info sheets to insert into the frames will be relatively cheap to replace as they weather or get vandalised. We are lucky in that we have never had a big vandalism problem down here – long may that last.
The Leopard toad season was a disaster, with only 3 known toads breeding, and we did see some eggs. No signs of toadlets, though. Maybe it was as a result of the dry winter, or maybe it was a cyclical thing. We shall just have to wait and see.
When applying for the Trust money, we budgeted for labour and tools, so now have a Sat morning gardener.
Another area of concern is that the planks on the boardwalk are slowly giving up and we will have to look ahead and see what can be done about these. We have re-nailed many of the planks down again, but they will have to be replaced at some stage.
Our new Councillor. Dave D’Alton, has said he is allocating funds for us next year. If this does happen, then we will find a reputable contractor to resurface some of the paths, which also badly need attention.
Regards Evanne & Terry
The Problem with Invasive Pest Plants
Since the 1600’s when European settlement of Southern Africa began in earnest, several thousand plant species have been introduced from other parts of the world. Most of these were deliberately brought in for agricultural purposes, sand dune stabilisation, to provide wood and fuel resources which were notably lacking in the Cape, or simply for ornamentation. Many other species have been accidentally introduced however, for example the various ‘passengers’ that arrived mixed in with horse feed which was imported from South America during the Boer War. Of the species which are officially recognised today as ‘problem’ species, about half originated in South or Central America, about one quarter hail from Europe, Asia and the Mediterranean region, and the balance came from Australia.
To understand why some plants become pests, one must realise that the deceptively peaceful natural environment all around us masks a continuous and ruthless struggle waged by all plants for nutrients, moisture, sunlight, and most importantly the chance to multiply and spread their genes. This competition becomes finely balanced through eons of evolution, with each living thing carving out a niche for itself by evolving strategies that enable it to survive and cast off sufficient seed to produce successive generations. Failure in this race of course results in extinction, and the ruthless adapt or die process has seen endless cycles of modification and extinction rolling on through the hundreds of millions of years in which life has existed on Earth. . However, if a particular species is able to secure a competitive advantage in this struggle, it will tend to rapidly outbreed and dominate other competitors, at least until others catch up by adapting in the on-going struggle.
Before the advent of modern man, plants which were gradually moving about the Earth by wind or animal dispersal had vast time scales in which to evolve new competitive strategies, but humans are today able to move species across continents literally overnight, thereby totally upsetting the slow natural evolutionary adaption process.
This mobility is precisely what brought the curse of invasive pest plants which today predominate in the Cape, the most prolific of these being the Pines which were introduced from both the Mediterranean (pinaster) and California (radiata). From Australia came many Acacias (Port Jackson, Long leaf wattle, Black wattle, Blackwood, Rooikrans and others), many Eucalyptus species, three varieties of Hakea, and Myrtle (Leptospermum).
Whilst the Pines and Eucalyptus were cultivated for timber, windbreaks and shade, the Acacias were introduced as a source of quick growing firewood, to act as sand stabilisers, and to provide timber in the case of Blackwood which is prized by furniture makers. The viciously prickly Hakeas made splendid barricades against marauders.
Of course this is not a one-way street, and many plants of South African origin have become problematic elsewhere in world – for example our Watsonias are pests in Australia, while vygies have become a major invader in parts of California where they were used as sand binders on highway embankments!
The runaway success of these introduced pests is due to several competitive advantages they can have over indigenous plant life…one successful characteristic is ‘overtopping’ where the pest plant grows taller than the natural veld, which then struggles for sufficient sunlight in the shade of the invader. Another advantage is to possess a deeper root system that sucks up much of the available groundwater. However, the greatest disrupting factor is their vast seed production that is rapidly dispersed by wind, birds or insects. Under normal circumstances, only a small proportion of a plant’s seed production survives to create a new generation, as the overwhelming majority succumbs to attack by insects or pathogens or other predators that have evolved to depend on this food source. The newly introduced plants do not suffer though from this competition, since their naturally evolved and specific natural enemies have been left far behind in their place of origin, thus allowing most of their seed to survive and geminate. In this way they are able to rapidly out-breed their indigenous plant competitors, and soon come to dominate the environment.
To get some idea of the enormity of the problem, consider that an estimated 10 million hectares of land is today infested to various degrees by invader plants in South Africa, and this number is continually escalating. Valuable agricultural land is destroyed, scarce water resources are dissipated and fire risks escalate, before one even considers the irreparable damage done to biodiversity. The cost of clearing invaders by mechanical and chemical means is daunting, and can be over R2 000 per hectare, depending upon the density and type of invader. Considering the immensity of the problem, tiny groups such as the FOSNA hackers can hope to make an impact only in relatively small and focused areas such as the Silvermine Reserve. On a larger scale, projects such as Working for Water contractors are making encouraging progress, particularly in vital water catchment areas and choked river systems. Even if the required funds and coordinated management of such a Herculean task could ever somehow magically materialise, the problem has now escalated way beyond any easy solution by comparatively feeble human physical control methods.
The only real hope of a long term solution lies in co-opting the forces of nature itself to restore the balance which we have so carelessly upset. This means bringing in the pest plants’ natural enemies from their countries of origin i.e. some of the symbiotic insects, pathogens etc. which evolved to keep them in balance back in their home environments. These so called bio control methods began almost 100 years ago in South Africa, with the introduction of a cochineal insect in 1913 that has been spectacularly successful in reducing the range of Opuntia (prickly pear cactus) infestation from over 400 000 hectares to negligible levels today. New techniques and agents and are continually being studied and developed by various scientific bodies such as the Plant Protection Research Institute and several universities, and they have already had notable success in controlling some Australian Acacias by the release of several host–specific wasps and pathogens. You will probably have noticed the prominent galls on long-leaf Wattle (they look like tiny apples ) and on rooikrans Wattle (small cluster galls), which are caused by tiny introduced Trichilogaster wasps that sting out the flower buds, thereby almost completely sterilising these pest plants. Another easy one to spot are the heavy and ugly fungal clusters which adorn most Port Jackson shrubs today and this is caused by the introduced Uromycladium rust fungus which debilitates and eventually kills this very widespread invader. Quite understandably, the question is always posed whether these introduced bio controls will one day turn their attention to our indigenous plants, and the answer is a definite no, for two reasons. The first being that only agents which are completely host specific can be considered, and the very careful and lengthy selection and testing process to ensure this before they can be approved for release. Secondly, the agents won’t ever run out of their chosen food resource, since they have evolved over the eons to be less than 100% successful, otherwise they would be committing suicide by destroying their own food resource and would therefore not have survived until the present time …..i.e. The agent invariably allows enough of its chosen ‘prey’ to survive which in turn ensures the agent’s own future survival. What happens is that as the food source diminishes, so does the agent’s own number diminish proportionately, thereby restoring the original balance of nature.
But to get back to the FOSNA hackers, we have over the years been able to remove large numbers of aliens within the Silvermine reserve by steadily plodding away with various manual clearing methods, so that today only scattered pines, acacias and hakea are encountered, and work on these survivors continues. The problem outside of the Reserve boundaries remains alarming however, and we are also helping other groups in the Peninsula to tackle their plant invaders.
When is a blue daisy not a Felicia?
An article entitled When is a blue daisy not a Felicia? written by Sheila Robinson, Corinne Merry, Frankie Shoosmith and Yvonne Viljoen. of the Flora Documentation Group of FOSNA appeared in the December 2011 issue of Veld & Flora . This was the first of a series of articles the group will be contributing to this publication describing memorable moments of wild flower photography.
Here is an abridged version:-
In early July this year, Sheila Robinson walked with members of the Kirstenbosch Branch of the Botanical Society on the Skyline Path in the direction of Noordhoek Peak. En route, they came across a little daisy that most of them took to be a Felicia tenella because of the narrow leaves and apparently typical blue ray petals and yellow composite central flower head. However, there was a dissenting voice that declared it was a Zyrphelis taxifolia that members of the Botanical Society had come across before. This led to a closer examination of the whole plant, accompanied by a lively discussion.
Sheila writes: I consulted our FDP working list of species we needed to photograph and I found that we did not yet have a photograph of Z. taxifolia. At home, I eagerly consulted various guides to confirm the identification based on our observations. I was looking forward to sharing this potential ‘discovery’ with my FDP colleagues and I hoped that I had bagged another species we could cross off our “Photos Wanted” list. At our next regular workshop, I showed my photographs to the group and we discussed the identification of this interesting blue daisy. As the flowers I had photographed were not yet fully open, we resolved to look for more of them to get better images”.
Subsequent attempts by Corinne Merry and Frankie Shoosmith to get better photographs were equally unsuccessful in Silvermine and Corinne began to search for these plants in other places. Finally, in August, Corinne found open Z. taxifolia ‘en masse’ on Table Mountain mainly along the Smuts Track, and Frankie found many open in Silvermine in early August. In early September they were still finding them in bloom.
Corinne then looked it up on the website of The Red List of South African Plants Online which provides “up to date information on the national conservation status of South Africa’s indigenous plants”. This source stated that Z. taxifolia is a montane fynbos species known from six sites from the Cape Peninsula to Hangklip. It is classified as rare, although not endangered.
So what are the similarities and differences between Felicia tenella and Zyrphelis taxifolia – neither of which have a common name – that lead to confusion and misidentification? Both are members of the Asteraceae [Daisy] Family. Both occur in fynbos and have flowering periods of several months in late winter and spring. Both have a single flowerhead on each flower stalk with central yellow disc florets and blue ray florets and, significantly, both have narrow [linear] leaves when compared to some other Felicias. These similarities resulted in Z. taxifolia remaining unnoticed for many years, even by interested and knowledgeable people.
The secret of distinguishing between them is partly where they grow – F. tenella prefers to be near water or in coastal dunes while Z. taxifolia prefers sandstone slopes which are damp. Other differences can be seen in the colour of their rays – F. tenella may have blue, violet or white rays while Z. taxifolia flowerheads have blue or mauve rays. But the main differences are in the detail of the leaves: F. tenella leaves are merely narrow and their edges [margins] have stiff bristles which feel like rough sandpaper, whereas Z. taxifolia leaves are needle-like and their margins have fine teeth [serrations].
The story of this memorable moment with a Cape wild flower can be told because several curious people asked questions, consulted their flower guides, shared their observations and brought to light a shy blue daisy that is not a Felicia.
Far left: Felicia tenella [taken by Sheila Robinson] 2nd left Zerphelis taxifolia [taken by Corinne Merry]
Reminder Note to our members:
FOSNA-FDP has produced a compact disc, entitled “FloraDoc” which enables you to explore all the flora of the Cape Peninsula selecting by Family, Genus, Species or common name. Over 2300 species are described and over 1300 species are photographed [3500+ photographs]. It is available for R120.00 from Kirstenbosch Botanical Garden Book Shop and from Yvonne Viljoen at 021-788 5620 or firstname.lastname@example.org
Forthcoming Environmental Days
- World Wetlands Day
February 02, 2012
- National Water Week SA
March 12, 2012 – March 19, 2012
- World Water Day
March 22, 2012
- World Meteorological Day
March 23, 2012
- Earth Hour
March 31, 2012
FOSNA is entirely self-funded, and our continued existence depends on our ability to raise funding by way of subscriptions, donations and information sales.
As a volunteer organisation our running expenses are very small, so that almost all the funding we raise can be applied to producing this newsletter, walks programmes, informational brochures and displays, and alien vegetation clearing programmes. We are also sometimes able to provide material support to the Silvermine Reserve, in assisting with the purchase of needed equipment and display materials. We feel sure that funding is well applied for the ultimate benefit of all Silvermine users, so please help us continue these efforts by making sure that your annual subscriptions are paid up….we are very grateful for your wonderful and on-going support!
The subs can be deposited / electronic payment into the FOSNA Account:-
Friends of Silvermine Nature Area
Standard Bank, Fish Hoek Branch (036009)
Account no. 073 852 317
Please forward proof of payment to me:
We welcome Wendy Rebello as a new member.
If you have any comments, criticisms, ideas or requests or anything of interest that you would like included in the newsletter please email it to me at: email@example.comAll contributions will be gratefully accepted and appreciated.