AUGUST 2020

 AUGUST 2020

August, that dry, windy month that drags us from the winter into spring, is always busy at the estate because of the school break, and this month was no different. A lot of folk got out there and did some hiking with quite a few families undertaking the new Zebra trail that traverses the Goudkoppies plains high above the Miner's Cottage, offering spectacular, albeit hazy at this time of the year, views over Hidden and Kliprots valleys. 

The end of August also marks the end of the rain cycle where we arrive at our final rainfall figure for the season past. I collected rainfall data from around the area and came to the conclusion that rainfall is locally erratic in these mountains. The official Mean Annual Precipitation (MAP) for the Lydenburg Montane Grasslands, of which we are part, varies from 660mm to 1180mm. That's some variation for a relatively small area. The lowest figure I received locally was Rivendell, west of us, with a MAP of 563mm, and the highest is Long Tom, south of us, with a MAP of 1067mm. North of us, the Rattray property reports a MAP of 676mm and ours is 894mm. Lydenburg towns MAP is 758mm. Rather variable I thought.

So I decided, just for interest's sake, to measure the rainfall from five different points on the estate for this past season (2019/20). The most northern point was the rain gauge at Pebble Creek (Unit 25). Then on the east, the point was Rock Solid (Unit 22). The south was Rainbow Rivers (Unit 17) and the west was the entrance boom where Patrick Mokoena stays and diligently guards us. The central area, in the opening between the Helipad and the manager's house is our central point and the point where our rainfall has traditionally been measured from. 

As you can see from the map, the five points are not really representative of the north, east, south , west and centre of the estate but they are, at least, representative of the estate. Following is a list with the recordings from these five locations on Finsbury Estate, an area of just under 3200 hectares:

1) North, Pebble Creek: 835mm

2) East, Rock Solid: 784mm

3) South, Rainbow Rivers: 637mm

4) West, Entrance boom: 719mm

5) Centre, Office: 704mm

Mean Seasonal Precipitation: 736mm

The seasonal figure, normally only measured from the Office area, is raised by almost five percent. And the north east of the estate recorded eighteen percent more rainfall than that recorded in the central area. There is a variation of more than twenty eight percent of the annual rainfall figure, normally taken on the estate, in an area of just below 3200 hectares. This certainly is erratic and will make a noticeable difference in moribund (in this case dry grass) build up across the estate and therefore the intensity of fires and planned burns. This will also affect the regrowth of alien plants and therefore my plans for follow-up operations. 

So we have modified (thanks Nick) the rainfall input spreadsheet on this site to accommodate all five of these points on the estate and we will continue to monitor rainfall at all of them.

Below is some other interesting fauna and flora that I encountered during the month of August:

The long, tubular flower of the Brown Jaybee, Jamesbrittenia burkeana, Allows only long-probiscid insects to access the nectar although some beetles have been known to chew through the base of the trumpet to access the nectar, bypassing the pollination process. This is a new species to add to our Finsbury plant list and I found it on the grassy slopes beside the gorge that runs from just north of M27 up toward Potato Seed Production. A scruffy bush reaching about a meter tall, the plants flower prolifically and are amenable to containers, making them suitable for outdoor pot plants in full sun. This species, together with two further identifications this month, bring our total number of Finsbury plants so far recorded on our list to 682 species! Closing in on that 700 milestone...

 

During my follow-up work and site inspections I have tried to explore as many gorges as possible to try and find more of the Elephant Foot vines (see blog posted on July 7), of which I have found five individuals to date (three males and two females). While exploring the gorge that runs from just below the sundowner spot in Hidden valley up to Mount Anderson with the Twiggs' from The Crofts (Unit 19), we came across these tiny, brightly coloured mushrooms attached to a rotting log. They are called Green Elfcup mushrooms, Chlorociboria aeruginascens, and, as you can see in the photograph, the mycelium also stains the wood a blue-green colour. The fungus is cosmopolitan, occurring throughout the world, and mostly attacks dead hardwoods, and when it occurs on oak, the wood is called Green Oak and has been used ornamentally in panneling as far back as the 16th century in Italy. It was also later used in Tunbridgeware in Kent in the 19th century and in parquetry (Wooden tiled flooring) since.

You've gotta love these names! Sticking to fungi, this is a forest of fungi called Lipstick Powderhorn, Cladonia macilenta, because of the bright red smooching lips at the ends of the stalks! The red tips are actually the apothecia which produce and distribute the spores used in reproduction. I found this in a moist, shaded area on the southern slopes of Mount Formosa in our neighbouring Emoyeni. This fungus is also cosmopolitan and occurs commonly on all the continents and has been found to produce a metabolite called biruloquinone which is a substance that effectively prevents neurodegeneration in Alzheimer's disease. Because of this breakthrough, a mass liquid culture system for the production of biruloquinone has been established in South Korea. The fungus is also rich in carbohydrates and it's close relative, Cladonia rangifera, grows in such abundance in the arctic that it is the staple pasture for Reindeer, Moose ,Caribou and Musk Oxen in the winter time where these animals access it by digging holes into the snow!

Many of you have mentioned to me that the Warthog population has increased dramatically over the last decade and I have certainly noticed it myself in the seven plus years that I have been here. I know that in fenced properties where Warthog predators have been removed, their populations explode and they become a pest that can be damaging to the environment, particularly in the dry season when they mostly dig for roots, tubers and corms. All our neighbours have also noticed this increase in population except for Cornel at Whiskey Creek to our south. He has not yet seen a warthog on his property. So I decided to set up a meeting with a grassland ecologist from the Mpumalanga Tourism and Parks Agency (MTPA) and a few of our neighbours' managers. We met at the MTPA offices at the hatchery in Lydenburg only for Frik Bronkhorst, the ecologist, to inform us that, as far as he was aware, warthog are indigenous to this area and were shot out, to the extent that they became locally extinct, probably during the second gold rush from 1930 onwards. This is because warthogs are asymptomatic carriers of the virus that causes African Swine Fever and this virus, although harmless to it's hosts the warthog, bushpig and soft ticks (which are the vectors), it is lethal to domestic pigs. After researching as much as I could on their natural distribution, it appears that they certainly should occur here all the way up to 2000 meters above sea level and I have not seen them much higher than that. Anyway, Frik and Trent, manager of the Rattray property are going to try to get some students involved to try and ascertain if the warthogs are pressuring the environment in an unsustainable way. What I initially thought was a potential problem actually turns out to be a great success story of warthogs reestablishing their population, by themselves, in an area where they were previously shot out. Pretty darn cool! (The photo was taken by our camera trap situated at K24)

This very, very ugly fly belongs to the Gonia genus in the Tachinidae family of flies. This huge family contains more than eight thousand species so far described and many more to come but one thing they all have in common, is that they are protelean parasites. These are insects that  begin life as parasites within the bodies of other arthropods and kill the host to enable them to emerge as free living adults. Most Tachinid females have a long, coiled uterus that enables the egg to be well-developed by the time it is laid on the body of the host. The egg then hatches quickly and the maggot burrows into the victim's body. The Gonia females, though, lay large numbers of their minute eggs on the food plant of the intended host and are ingested while the host, perhaps a fat worm, guzzles its leafy meal. Once inside its host, the maggot allows it to survive normally, albeit in poor shape, as it feeds on tissue within the host and avoids the important organs until it is ready to pupate. Then it will eat the organs and kill its host, pupate within the shrivelled cocoon that its host has become and later emerge as an adult fly. Now that is the stuff of horror shows!

A close-up of the numerous tiny, mauve and white flowers that make up the showy inflorescences adorning the Sagewood trees, Buddleja salviifolia, that have been in full bloom for the entire month. This colourful show helps us realise how common these small, scruffy trees are in the estate riparian areas and forest fringes. This is a good thing because their leaves are nutritious and enjoyed by the many browsing antelope we have here. The pleasantly fragrant little flowers, which are tubular with hairs between the tubes and the lobes, are also attractive to bees and butterflies, its pollinators, which in turn attract birds. This fact, together with the fact that the plant is quick-growing, drought-resistant and easily hedged, make it a popular subject in indigenous nurseries. To top it off, I was told that the leaves, boiled while still green, produce a tasty herbal tea and so I tried it and the result was a very pleasant, smooth and tasty tea!  

As I reluctantly emerged from my warm, cozy house on one of the colder mornings during the month, I looked down to see a whole bunch of Pugnacious ants, Anoplolepis custodiens (see blogs March 2019 and April 25 2020)  ), lying in a group, on the pathway, as if dead. I returned a short while later and noticed that one appeared to move slightly. I touched it gently and it stood up and began to groom itself. I touched another and the same thing happened. After a while others began coming to life on their own. Within fifteen minutes they were all up and running around with their usual haste. This is what happens to ectothermic (cold-blooded animals) when the ambient temperature moves above or below their operating temperature. Us endotherms (warm-blooded animals, can operate in any temperature because our metabolism keeps our bodies at a relatively stable temperature. The disadvantage of this is that we need to eat a lot more than cold-blooded animals. Now regarding these ants, in their subterranean nests, when it is colder, the workers tending the eggs, move the eggs and pupae two or more times a day to parts of the nest that are warmer at that time and the ants move to the warmer parts as well. Clearly these ants were caught outside the nest when the temperature dropped below their operating temperature and they simply collapsed until it warmed up again. Not something you see every day although I did, once, find a small Brown Water Snake on a path when it was very cold early in the morning and it was also unable to move until it warmed up, like these ants.

This stunning daisy lighting up the high altitude grasslands far above the Steenkamp's waterfalls is a reminder that day-length has increased to the point that triggers many plants into their growing phase. Spring-time is on the way! This is a Gerbera ambigua and it is one of three species that occur on the estate with a fourth and more famous species, Gerbera jamesonii, or Barbeton Daisy, occurring in our neighbouring Rivendel and the Lydenburg bushveld biome. The genus is named after the German botanist Traugott Gerber (1710-43) who was a friend of Swede Carl Linnaeus (1707-78), who devised the taxonomic system that we use today to classify living things. Towards the end of the nineteenth century Gerbera x hybrida was created by crossing the barberton daisy and the green-leaved daisy, G. viridifolia (which is found on the estate), and this is from where the thousands of cultivars come today. Gerbera is the fifth most used cut flower in the world, after rose, chrysanthemum, carnation and tulip. 

A Chorister Robin-chat, Cossypha dichroa, in a very relaxed pose while perching on the parking poles next to the hatchery. He/she is one half of our local pair that call the office area home. In the latter half of August and beyond, the male asserted the presence, and dominance, of the pair in loud, whistling song from the thickets between the offices and the museum. The powerful whistling song is a jumble of notes but is often interrupted by whistles that mimic other birds or animals. I have heard one mimic a Fish Eagle. The pair bond is powerful and they remain together for life and while the female builds the nest and incubates the eggs, the male assist in raising the chicks thereafter. They are usually secretive, confined to the thickets which makes the call rather eerie but this pair have really habituated around people that they will perch out in the open like this.  

Winter coming to an end means more chance of spotting snakes. Bumped this little Berg Adder, Bitis atropos (see blogs from 9 Jan 2017 and May 2019), on the KLF road high above Hidden valley and got down really close to it. It lay there, dead still, until I got within a foot of it. Then the tongue began to dart in and out of its closed mouth. It was trying to pick up particles of my scent on its forked tongue, which it then inserts into a double-lobed gland, the vomeronasal gland, in the roof of its mouth. This olfactory gland then analyses the scent particle. The advantage of having a forked tongue is that it helps the snake pin-point the direction the scent is coming from. If it spreads the tips apart, more particles will occupy the tip on the side in the direction from which the scent originates, than on the other. This is particularly important to adders because they strike and envenomate their prey and allow the victim to run off. Once the snake has waited long enough for the venom to immobilse the prey item, it will begin to track the victim down by scent, for which it uses its forked tongue.  

Louise Twiggs, the nature artist, has painted a beautiful watercolour of a Mount Anderson Everlasting, Helichrysum summo-montanum, and donated it to the estate. It is displayed in the office. That individual plant that she painted was one of only two plants that I had encountered on or near the estate right up until this month. I visited that plant multiple times each year during the winter, which is when they bloom, and never found any of its flowers fully open. This month, while on a hike through Emoyeni property with the Moore's from Rock Solid (Unit 22), we discovered a whole group of these plants and some had flowers that were fully open - a first for me! The plants prefer to grow on sheer cliffs so it took some time and a little risk to finally get my photograph of the open flowers. What makes the plant so special here for us is that it is regarded as a narrow endemic, meaning that it is only found here, in an eight kilometer radius between Mount Anderson and Mount Formosa, in the entire world. Even the scientific name is beautiful, it means: "The golden sun on the mountain top!" 

As I mentioned at the beginning of this blog, I have been trying to explore as many gorges as possible, hoping to find more Elephant's Foot vines. This is the gorge that runs from Bulldozer Creek up to Little Joker Koppie and it is quite spectacular. Fraser Moore from Rock Solid and I decided we would attempt to reach the very top without having to exit the gorge. I struggle to understand why I though I didn't need wet /dry clothes and shoes. It sure was fun. But, phew, did we get wet!

Spring time has arrived and with it will be all the birds, flowers and babies!