Lichens and mosses

A leafy foliose lichen (Xanthoparmelia substrigosa) on the trunk of my Acacia karroo tree

After heavy rains we had in early April, many of my trees, and rocks, sported lichens and mosses, totally fascinating! And now, two months later, they are still there, but have turned pale grey. But understanding lichens is complex (to me at least!), so I've had to resort to an internet search to explain them.

Worldwide, over 20,000 species are known. A lichen is not a single organism. Rather, it is a symbiosis between different organisms - a fungus and an alga or cyanobacterium. Cyanobacteria are sometimes still referred to as 'blue-green algae', though they are quite distinct from the algae. The non-fungal partner contains chlorophyll and is called the photobiont. The fungal partner may be referred to as the mycobiont. While most lichen partnerships consist of one mycobiont and one photobiont, that's not universal for there are lichens with more than one photobiont partner. When looked at microscopically, the fungal partner is seen to be composed of filamentous cells and each such filament is called a hypha. These hyphae grow by extension and may branch but keep a constant diameter. Amongst the photobionts there are those that are also filamentous in structure while others are composed of chains or clusters of more-or-less globose cells.

Given that they contain chlorophyll, algae and cyanobacteria can manufacture carbohydrates with the help of light via the process of photosynthesis. By contrast, fungi do not make their own carbohydrates. Every fungus needs existing organic matter from which to obtain carbon. In a lichen some of the carbohydrate produced by the photobiont is of course used by the photobiont but some is 'harvested' by the mycobiont.

Lichens are classified with the fungi (being sometimes referred to as lichenized fungi) and can be found growing in almost all parts of the terrestrial world, from the ice-free polar areas to the tropics, from tropical rainforests to those desert areas free of mobile sand dunes.

Foliose lichens could be thought of as halfway between crustose (two dimensional) and fruticose (erect). Though obviously three dimensional, they grow in a more-or-less sheet-like form, but often with a lobed appearance. They are not attached by their entire lower surfaces to their substrates. Indeed, some foliose lichens are just centrally attached.

Another part of the same tree trunk, lower down, was covered in moss. Now Wikipedia says, "Mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple, one-cell thick leaves, attached to a stem that may be branched or un-branched and has only a limited role in conducting water and nutrients."

The same thick mat of moss also formed on a rock on my patio, but both of them never quite got to the thick stage and have now all but disappeared. The moss life-cycle starts with a haploid spore that germinates to produce a protonema (pl. protonemata), which is either a mass of thread-like filaments or thalloid (flat and thallus-like). Massed moss protonemata typically look like a thin green felt, and may grow on damp soil, tree bark, rocks, concrete, or almost any other reasonably stable surface. This is a transitory stage in the life of a moss, but from the protonema grows the gametophore ("gamete-bearer") that is structurally differentiated into stems and leaves. A single mat of protonemata may develop several gametophore shoots, resulting in a clump of moss. But they do need a lot of damp to continue surviving.

Most mosses rely on the wind to disperse the spores, but It has recently been found that microarthropods, such as springtails and mites, can effect moss fertilization.

Image credit

It seems that, given enough moisture, moss might still take over the world! lol!

Black-headed Heron (Ardea melanocephala)

I had an awesome visitor this morning, a Black-headed Heron (Ardea melanocephala). We don't often see them, mostly just after a veld fire, when they will snack on some unfortunate crispy tit-bits left in the wake of the fire. But this morning he was close to my garden fence and, as previously, didn't seem that perturbed about me taking some photos.

They mostly hunt near water, but will also hunt well away from water, taking large insects, small mammals, and birds. It will wait motionless for its prey, or slowly stalk its victim. It's fascinating to watch, but his patience long outlives mine, as he can stand motionless for longer than 10 minutes and by that time I think he's fallen asleep! Both sexes are alike, so I have no idea whether this is a male or a female.

Monogamous and usually colonial, they breed in small, mixed-species heronries. The male calls from a perch to attract a mate, raising its head and giving a loud yelp, sometimes extending its bill vertically as it does so. I've only heard that sound once, and I was totally thrilled!

African Striped Skink (Trachylepsis striata)

This Striped Skink was enjoying the sun on the wall of my bathroom court-yard garden and she was heavily pregnant (pic taken last October). Mating occurs between October and November, with a gestation period are 90 to 100 days, so I presume she was to give birth within a month or two, usually a single litter of 3 – 9 babies. Growth is relatively fast, sexual maturity is reached in 15 – 18 months. Last summer, my Skinks had several litters in my bathroom court-yard garden, much to my delight.

The African Striped Skink (Trachylepsis striata), commonly called the Striped Skink, is a lizard in the skink family (Scincidae). The species is widespread in Southern Africa, including extreme southern Angola and Zambia, Namibia, Botswana, Zimbabwe, Mozambique, and parts of central and eastern South Africa.

Skinks typically seek out sheltered environments out of the elements, such as thick foliage, underneath man-made structures, and ground-level buildings such as garages and first-floor apartments. When two or more skinks are seen in a small area, it is typical to find a nest nearby. Skinks are considered to be territorial and often are seen standing in front of or "guarding" their nest area.

Two males squaring it off, ready to defend their territory

This skink is brown or bronze coloured with two yellowish stripes that run lengthwise on either side of the spine. Both sexes grow to a length of 25 cm.1 Their tails are often missing due to predators.

To bless this kind earth... and yourself

Now that we're over the worst of summer (and it really was the pits, with extreme heat-waves, temps in the 40℃'s and drought) and had some lovely rain to break the heat and drought, I'm enjoying time outside in my garden again. I just get absolutely cranky, and listless, when it gets that hot, and can't seem to get around to doing anything outside. But as we all know, we NEED to get outside, we need to spend time in nature, otherwise life becomes unbearable. Well, for me anyway. My plants and the birds in my garden are part of my family, and I feel as though I've lost track of what's going on in their lives. I just did the bare necessities during that heat, filling the water bowls and feed tables and the rest, like watering the garden, was left up to my trusty garden manger, Chrissie. I even thought of telling her to chat to the birds, because I wasn't getting round to it!

But my garden doesn't seem to have minded my absence. It's like a jungle out there after all the rain. Nature's revenge to neglect is that, when left undisturbed and given time, she will reclaim anything built by humanity. So basically, no need to feel guilty here, life finds a way.

 There's a pathway somewhere in there, totally covered now by Bulbine and Sword ferns.

Even the birds don't seem to have noticed my absence. No excitement or fluttering or welcoming twittering when I started spending time in the garden again. Maybe they were even pleased about not being constantly stalked by my camera. Eating and bathing and nesting carried on as usual, making me feel a bit unwanted...

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Hedgehog lore and legends - Snakes alive!

Are hedgehogs in danger from snakes?

It's not surprising that such a strange-looking little animal as a hedgehog should be the subject of some extraordinary legends and beliefs. Strange hedgehog activities such as running in circles and 'self-anointing' (smearing their spines with their own frothy saliva), are definitely fact, not fiction, through we don't know why they do these things.

But there are also a number of intriguing legends about hedgehogs, most of them dating back to the distant past.

The myth, particularly prevalent in South Africa, that snakes have been found with hedgehogs in their stomaches, is a long stretch of the imagination. It would be quite impossible for a snake, no matter how big, to swallow a rolled-up hedgehog.

A hedgehog under attack from a snake would immediate roll up and protect itself with its bristling spines. If the snake persists, it is likely to damage itself severely on the spines, and the hedgehog may seize the opportunity to sink its teeth into the snake and roll up again. In the end, the hedgehog often makes a meal of its former enemy!

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Have we evolved for the better?

The animal kingdom is filled with almost an infinite variety of creatures. Scientists discover new species and sub species every year. Each one is a wonder onto itself and one could labour for years to uncover its secrets. It is an unfortunate fact that the closest that most of us get to wildlife is through bars at the zoo. Our urban lifestyle has the effect of cutting us off from the glorious world of the animal kingdom.

Every animal has a lesson to teach us that we are not hearing. We may think that we have evolved, the question is, at what cost?

A Butterfly Life
As the caterpillar sleeps inside its cocoon

Like a baby wrapped in her blanket 

She waits and waits until she blooms 
Into a beautiful new life 

With wings of deep sapphire blue

She takes her first flight, soaring high
Into the clear cornflower sky

She flutters over to perch on the pink flowers 

To sip the sweet nectar of pure gold 

But this butterfly is daintier than a ballerina

Like a leaf in the wind, but controlled

So delicate and fragile

But so free, so free this butterfly will always be.

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BULLFROG at my pond - 1am 10 Nov 2015

Image from Milan Zygmunt 500px

The most wonderful sound to wake up to - the call of a Bullfrog (Pyxicephalus adspersus) at my pond! I haven’t heard one for years, so I immediately jumped out of bed (at 1am!), grabbed the torch and rushed to the pond. It took me quite a while to find him - first of all he heard me, so kept quiet for a while, but then continued - and secondly the torch light was rather dim. But eventually I found him. There he was! Cleverly hidden under a large rock in the shallows. I did have my camera with me, but the pics showed nothing in the darkness. So I looked for him the next morning and did find him (I in fact found two), but he was not nearby the size of the pics below - a youngster, about 10cm (4”) long and the minute he saw me, he left the safety of the rock he was hiding under and swam to deeper waters. So once again, no pic. It’s hard to believe that such a small chap can have such a booming voice!

The large rock (top right) under which he was hiding

Their loud booming calls (to attract a female) can be heard for miles and the first time you hear it (for me it was in the early 80’s at my previous wildlife pond), you’re not sure whether to investigate or to flee!

This species occurs widely in South Africa, Swaziland, Namibia, Botswana, and Zimbabwe, extending north to southern Angola, Zambia, Malawi, Mozambique, Tanzania, and Kenya. One of the most adaptable amphibians on earth, Pyxicephalus can tolerate some of the harshest environments in Africa. Certain areas of their range can be completely dry for years at a time, and can reach surface temperatures over 100 degrees F, and drop to below freezing during the winter. Protected in an underground estivation chamber, the frogs wait it out until more suitable conditions occur. When the rainy season begins (usually November), they come out of their chamber, occupy temporary floodplains and rapidly drying puddles scattered around the African countryside, just for a few short days or a couple of weeks.

I am totally thrilled that they have taken up residence in my garden!
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Image from BioLib

It is the largest amphibian found in southern Africa. Males can reach a snout-vent length of 24,5 cm and a mass of 1.4 kg

It is common in many of the southern parts of its range, it has apparently declined in South Africa, especially in Gauteng Province, but it is still locally common in some places. Boycott (2001) declared the species to be extinct in Swaziland. It seems to be very uncommon in the northern parts of its range, with very few confirmed records from Zambia, Malawi, Tanzania and Kenya (though this might in part be due to identification problems)..
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Photo Copyright by © Steven G. Johnson

Photo African bullfrog SA Reptiles
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It is a species of drier savannahs. It is fossorial for most of the year, remaining buried in cocoons. They emerge at the start of the rains, and breed in shallow, temporary waters in pools, pans and ditches. They are active by day during the breeding season. They can tolerate habitat alteration, but not urbanization.

Male Pyxicephalus adspersus can reach lengths of more than 9 inches and weigh over 2 pounds. Females are much smaller. Males are olive in colour, with yellow to orange on the throat region. Females are olive to light brown with cream to white throat areas. Both sexes have ridges running laterally on the dorsal surface. Juveniles are much more colourful than adults. Several white to yellow lines run down the animal's dorsal area on an overall mottled background. Both these dorsal lines, and mottling disappear with age. Adults have a spade like metatarsal tubercle on each hind foot to aid in digging. The front toes are thick and blunt with no webbing, the rear toes are slightly webbed. These frogs have massive skeletons with extremely large, heavy skulls. The bottom jaw has three odontodes which act as huge teeth, and are used in restraining struggling prey.

During the breeding season, males will congregate in large groups. Much aggression occurs in these groups with larger males pushing, pursuing, biting, even consuming smaller males. The large males will push their way to the centre of the group, establish and defend a small area and begin calling. The call lasts about a second and can be described as a deep low-pitched whoop. The females will hear this call and swim underwater to the centre of the group, to avoid the smaller males and surface in the defended area of a larger male. As they surface, they are persuaded until finally being seized by a male. Amplexus occurs in shallow water to allow the pair to stand on the bottom. Eggs are fertilized above the water's surface. As many as 4000 eggs may be released. The males exhibit parental care. Males will watch over and defend the eggs which hatch in two days. After hatching, the tadpoles will feed on each other, as well as on small fish and invertebrates. Defending males will continue to watch over the tadpoles which will metamorphose within three weeks.

Behavior
These frogs have a short active period depending on the rainy season. The majority of their lives are spent estivating underground. Adults will burrow underground using the metatarsal tubercle on their powerful hind legs. Juveniles lack this tubercle and must resort to utilising an existing burrow made by some other animal. They slough off several layers of their skin's epidermal cells which form a tough cocoon. Most of their bodily functions slow or shut down all together. This period of dormancy may last a year or more. During the rainy season frogs will sit partially buried with the nose exposed, taking advantage of any smaller animal unfortunate enough to pass by

Food Habits
Pyxicephalus adspersus is carnivorous and will consume nearly any animal that can be overpowered and can fit in their huge mouths. Cannibalism is a common occurrence beginning the moment they metamorphose. Many of their first meals will be a member of the same egg mass. Other prey items may include invertebrates, other species of frogs, reptiles, small mammals, and even small birds. The tongue is folded over inside the mouth. To capture a potential meal, it will drop its lower jaw with considerable force, causing the tongue to flip over and out of the animal's mouth, seizing the prey

Did you know?
Certain areas of their range can be completely dry for years at a time, and can reach surface temperatures over 38 degrees C, and drop to below freezing during the winter. Protected in an underground estivation chamber, the frogs wait it out until more suitable conditions occur. In fact, the majority of their lives are spent estivating underground. They slough off several layers of their skin's epidermal cells which form a tough cocoon, which prevents the evaporation of body fluids. Most of their bodily functions slow or shut down all together. They absorb water stored in their bladder. This period of dormancy may last a year or more. When the rainy season begins, they occupy temporary floodplains and rapidly drying puddles scattered around the African countryside.Males have two breeding strategies, depending on their age: Younger males congregate in a small area, perhaps only 1 or 2 square meters of shallow water. The larger males occupy the centre of these breeding arenas or leks and attempt to chase off other males. In fact they fight, causing injury and even killing one another. The dominant male attempt to prevent other males from participating in breeding. A female approaches the group of males by swimming along at the surface until she is within a few meters of the group. Then the female dives to avoid the smaller males and surfaces in the defended area of a larger male in the middle of the group. She is soon grasped by one of the larger males, and mating ensures. Most of the females are mated by the dominant male in his territory.

The major threat through most of its range is harvesting of frogs for local consumption, which is believed to be responsible for some population declines. In South Africa, breeding habitat has been lost due to urbanisation. This species is sometimes found in the international pet trade but at levels that do not currently constitute a major threat.

Economic Importance for Humans: Positive
African bullfrogs are eaten by humans, and have been collected for the commercial pet trade.

Economic Importance for Humans: Negative
Because these frogs are such resilient animals, they might potentially have negative effects on the surrounding ecosystem if introduced by humans beyond their natural range.

Listed as Least Concern because, although it is losing breeding habitat in places due to urbanisation, and it is also eaten in parts of its range, it has a wide distribution, is tolerant of a broad range of habitats and has a presumed large population.
(Much of this info from Animal Diversity Web)

Giant Bullfrog (Pyxicephalus adspersus). This fascinating frog species can be viewed by the general public at The National Zoological Gardens of South Africa (NZG). NZG has decided that, in addition to having several amphibian species on display, it will also want to play a role in the conservation of frog species in situ (in the wild). A starting point for the NZG will be to install an on-line weather station on the site in order to correlate amphibian behaviour with environmental conditions.

NZG details :
Tel: +27 12 328 3265, Fax: +27 12 323 4540 | 232 Boom St, Box 754, Pretoria, 0001, South Africa.

At last somebody is doing something about our declining amphibian population! Thank you NZG!

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