Wednesday October 18, 2017

The Marlothii Conservancy

The Marlothii Conservancy is registered with the Mpumalanga Parks Board as an Urban Conservancy and was the first in Mpumalanga to do so. It aims to generate interest and active participation by registered land owners, accredited residents and the business community in the conservation of indigenous and endemic fauna and flora and the protection of the environment in the area based on scientific principles of nature conservation and sustainable utilization of the area's natural resources. The Conservancy exists in partnership with the Marloth Park Honorary Rangers and the Marloth Park Property Owners Association. You can see our registration certificate by clicking here and read a brief historical note by clicking here.

GRASS AND ITS IMPORTANCE

Grasses belong to the plant Family Poaceae which is one of the largest plant families in the world with about 9 700 species world-wide. Of this number, 967 species have been described from Southern Africa, of which 329 are endemic to the region and about 115 introduced. Wheat, maize, sugar cane, rice and sorghum are all grasses.

Grasses are characterised by 'nodes' along the stem - or jointed stems - as opposed to 'sedges' which have stems with no joints and which belong to another Family. For proper identification, the botanical names of grasses should be used as common names can be very misleading.

All grasses belong to the classification known as Monocotyledons, as opposed to trees and shrubs which generally belong to Dicotyledons. All Monocots grow from seed with only one leaf shoot, while Dicots grow from seed with two leaf shoots. The importance of remembering this is that Monocots grow from the base of the stem whereas Dicots grow from the upper or outer tips of the stem and branches. All grasses therefore grow from the base of the stem and leaves.

The ecology of Southern Africa's grasslands is affected by grazing, fire, rainfall etc. - all these factors play a significant role in the species composition and health of a grassland.

If herbaceous plants and trees (Dicots) are browsed or bitten by animals, the growing tip is destroyed and the plant reacts by putting out alternate shoots. This has the effect of causing the plant to 'coppice' and the plant generally produces a denser growth. However, if grasses (Monocots) are bitten or grazed by animals, the growing part is not destroyed and it will continue growing from the base, with the bitten tips remaining a feature. This is an extremely important difference between the Monocots and Dicots. The utilisation of grass species by grazers can thus easily be identified due to the amount of foliage removed.

Through the process of 'photosynthesis', leaves produce carbohydrates (food energy) from sunlight, minerals, CO2 and water. The energy to produce growth, however, is obtained from energy stored in the roots. As the grass plant grows so it withdraws from the roots until it has manufactured enough energy to restore that taken from the roots. If a plant is grazed immediately and frequently as it tries to grow, it will be unable to replace root energy and the effect is that the rootstock will be weakened or diminished and eventually the plant can die.


Even one herbivore, confined to an area, will nibble away, preventing any 'rest' period for the plants to grow and renew root vigour. If we started nibbling at growing vegetables in our garden, they would not grow into mature plants and certainly would not reach the stage of producing seed. Exactly the same happens with growing grasses -- they need a rest from grazing and have a time to grow.

The lack of rest and growing time is caused by what is known as 'constant nibble' and in certain cases constant nibble can be effected by only one herbivore. Ecologically, rest time is the important factor and not numbers of grazers.

There are grass species adapted to almost every terrestrial habitat on earth. In 'pioneer' situations the grass forms tend to rely on seed production to carry them over unfavourable conditions.

Most of the pioneer type grasses have narrow leaves, or some other method of cutting down transpiration, and an abundance of pointed shaped seeds that can lodge in bare ground that is often compacted by hooves. Pioneer grasses are generally unpalatable to most grazing animals, thus increasing the grasses chance of survival. Seasonal grasses are termed annuals and they tend to indicate poor veld condition. Marloth Park is a prime example.

Certain other grasses rely on vegetative expansion. These 'creeping' grasses send 'runners' out from an established base. Should the runners encounter a suitable growing patch they will send down roots from the nearest 'node' and establish another plant. An example is the Cynodon spp. Species of this growth form have low, lateral growth, often with a large percentage their mass underground. The leaves of these types of grasses are usually tough and hard to graze resulting average palatability but the juicy root stock, in sandy soils, is utilised by warthogs, mole rats and springhares.

As conditions for growth improve the grass species tend to become broader leafed. The seeds become rounder, enabling them to drop between the increased ground cover. With these grasses becoming more attractive to grazers, animal droppings and hoof action further improve water infiltration, nutrition and other conditions for growth. Panicum spp. and Setaria spp. are typical examples. Where grass plants survive through successive seasons in vegetative form they are termed 'perennial'.


The occurrence of perennial species indicates improved veld conditions. With increased competition for light, the grass species grow taller with more bulk and provide better soil protection. In many cases they become less palatable with inedible stems, like the grass used for thatching. It should be remembered that almost all grass species are palatable when young but as they grow and age the cellulose content increases at higher rate in some species resulting in reduced palatability. Cymbopogon spp. are good examples of this.

The leaves of many of these tall grasses are only accessible to certain ungulates with the necessary adaptations. The horns of both male and female Sable and Roan antelope, as examples, help part the long grass stems to reveal the palatable leaves below. If the adapted species of antelope are missing, these grasslands may become unutilised and 'moribund'. The long grasses found in the vicinity of Pretoriouskop in KNP are good example and Sable are often seen in that area.

Too much shading from moribund material can smother plants and result in die off. Under-utilisation of grasses, while resulting in better soil cover, is nearly as detrimental as over utilisation. There is a very necessary relationship between grazers and grasses. In natural circumstances the 'coarse grazers' (like Cape buffalo) will move through thick swathes of grass, opening it up for other species, which will shorten it further, making it suitable for the next species, and so on through the season.

The various species of ungulate assist each other with this type of interaction which results in ideal grassland management, producing a trampled mulch to retain moisture and permit light penetration. Essentially the moribund material is “converted “to mulch. Where this doesn't occur the use of fire either naturally or artificially created may become necessary to maintain ideal conditions. 

Many people consider veld management to involve solely the numbers of animals in a particular area. Under natural circumstances that is not true, animal populations would move around to the best grazing areas, unhindered by fences. Herds would tend to aggregate in large numbers at the end of the dry season, when they had to keep on the move to find food. It this way they acted like a natural mowing machine. When the rains arrived the large groups split up into their herds once more, with the benefit of 'new blood'. These natural systems enabled the grasses to receive the required rest periods for growth.


Unfortunately as soon as there is a game fence surrounding the area, the above does not apply and animal numbers and the type of animal needs to be controlled.

Regardless of the number of animals, moving herds leave rest periods for the grass plants to grow. The damage of 'constant nibble' is caused by confined populations or animals 'anchored' to artificial and often badly sited water points. If the grasses are not getting the required rest during the growing period then the veld management is faulted and the ecological balance of the grassland will suffer.

SO WHAT DOES THE ENVIRONMENTALLY CONSCIOUS PERSON THAT LIVES IN MARLOTH PARK DO ABOUT THE LACK OF GRASS?

In one aspect it is easy to say what must NOT be done.

1.      Even though the Municipality may allow certain types of fences to be erected around part of your property it does not mean that you MUST do that. It’s quite simple, if you are concerned about the environment in Marloth Park don’t put up a fence.

2.      Do not remove the vegetation around your house. In case you have not noticed animals don’t eat sand or soil as part of their diet. (and yes I know that geophagia does exist)

3.      Do not alter this bushveld to suit your own personal needs, in fact it is the humans that need to alter their attitude and adapt to this environment.

In my opinion if the above cannot be accepted then you should not live in this type of environment but rather stay in the cities which are places that have been modified to suit a large number of human requirements.

What I find quite amazing is that when one speaks to people that have done any or all of the above they all have some “valid” reason and that what “they” have done is actually not detrimental to the environment.

 

NEXT TIME WE WILL DISCUSS THE MORE PRACTICAL ASPECTS OF GROWING DIFFERENT TYPES OF GRASSES IN MARLOTH PARK.

 

 

Comments (0)

500 characters remaining

Cancel or

Top f