Build on vision, driven by passion and having faith in God

[Home]  [About Ferdie]  [Photography]  [Videos]  [Birding]  [Safaris]  [Courses]  [Articles]  [Web design] [Contact us] [Links]

LIVING ON THE EDGE by Dave Rushworth

 

Ecologically speaking, on the edge of a vlei, on the edge of a forest, on the edge of a water body means that you are also on the edge of some other habitat.  We are not isolated in this world and every type of habitat adjoins another type.  This interface between habitats is usually called an 'Ecotone'.   These ecotones are normally the most inhabited and therefore the most important parts of the environment.

For instance, Sable rest in the shade of a woodland and then venture out into a vlei to feed. Crabs take refuge and feed in water and then venture out onto the shore to feed on other foods and to burrow. Birds sit in trees at the forest edge and hunt out into the grassland. The littoral zone of the sea shore is a well known and much publicised example.

While animals find ecotones the most attractive areas to live in, human beings, wishfully at one with nature, have the same attraction. One only needs to survey the number of coastal cities and towns on each continent. The shorelines of large lakes, river banks, forest edges, areas adjacent to mountains are all sought after dwelling sites. With insensitive humanity there is obviously going to be a clash with the natural world. The effect of effluent and emissions has even further impact.

On the local scene and in other rural areas the effect of humans can be just a damaging if proper ecological planning is not taken into consideration during 'development' schemes.

The edges of vleis make a firm, cleared and attractive site for roads. Rivers offer natural boundary lines between properties. Open grasslands, which are quite often flight paths, offer uncluttered routes for power lines.  Generally the ecotones are an easy option for development. The hazard of power lines to flying birds is well documented.  Roads along grassland or vlei edges pose a great disturbance and sometimes a physical hazard to animals using the ecotone. With our extensive shoreline, vehicle travel along the marine littoral zone by careless humans is well known.  The same applies to roads and other activities on the shores of 'dams' and lakes. One positive factor of cleared areas along ecotones is that they provide firebreaks between habitats with different burning regimes.

The point intended is that landowners and developers should be aware of the potential damage and disturbance that can be caused by expedient use of ecotones. Rather zig-zag roads in and out of forest edges. Instead or a ring road round a dam have in/out roads down to view points. Place water points where the hoof pressure will not cause erosion to valuable grazing areas. Quite often the different habitats will be characterised by differing soils types and these soil contacts often coincide with the ecotones. Where the soil contacts result in 'sodic' conditions extreme damage can be caused by aligning roads along the attractive, sometimes bare and very 'brittle' areas.

Before any action takes place survey the area. Note what lives there and put yourself in the place of the natural inhabitants. Make the utmost effort to disrupt other life cycles as little as possible. Because humans are part of the world there will always be some effect by anything we cause.  Winrows on a graded road may not seem much to us but they are insurmountable mountains to a tortoise or to some insects. Trapped on an open road they 'fry' to death unable to escape the heat of the sun.  Animals may miss their vital daily drink by vehicle disturbance cutting off their access to water. Low 'hot wires' on electric fences are death traps to tortoises, pangolins and young carnivores needing to cross human boundaries.  There are many examples.