Table 1 Examples of naturally occurring, unintentional and deliberately created human made factors that may promote isolation
From: Field site selection: getting it right first time around
| Â | Natural isolating factors | Human activity with incidental effects | Artificial and deliberate methods |
|---|---|---|---|
Physical barriers | Sea, large rivers and lakes, mountains and hills, desert and barren or poor terrain | Buildings, roads, railways | Insecticide, drainage |
Vegetation | Unsuitable habitat type, excessive shade, no shelter | Large monospecies plantations | Land use change e. g. clearing and planting |
Distance | Between suitable habitats, to nearest host | Sparse human presence, no farm animals, no plumbing or irrigation | Zones with no host, no natural or human-made breeding sites etc. |
Time | Seasonal events, flood, animal bird migration | Crops, animal movement | Time limited or interrupted water supplies |
Temperature | Seasonal changes, latitude, altitude | Â | Â |
Competition | Neighbouring habitat zones favour a competitor | Â | Promotion of benign competitor or predator |