10.3 Species Diversity and Human Activities 

Impact of Agriculture

• Farmers control which species can live in an agricultural habitat depending on which are the most productive and make most money
• Therefore the %%number of species and alleles decreases to only those favourable%%
• To be economic a large population of favourable species have to be present but %%habitats can only support a certain biomass%%
• %%Left over lands and resources is competed over by other species%%, many of which do not survive the competition
• In addition, %%pesticides are used which reduce the number of ‘pests’ like bugs%%

Balance Between Conservation and Agriculture

• Food is necessary for human life and some amount of agriculture is needed to sustain the population
• Agricultural land has increased and use of pesticides etc has increased exponentially
• Certain practices have directly reduced species diversity and removed habitats
  • %%Removing hedgerows and grubbing out woodland%%
  • %%Creating monocultures%%
  • %%Filling in ponds, drained marsh and other wetlands%%
  • %%Overgrazing of lan%%d
• Other indirect methods have been used too such as…
  • %%Use of pesticides and inorganic fertilisers%%
  • %%Escape of effluent from sewage and slurry tanks into water%%
  • %%No crop rotation and lack of intercropping%%
• Conservation techniques have been put in place such as…
  • %%Maintain hedgerows to beneficial size%%, A-shape more beneficial than rectangle
  • %%Plant hedges rather than erect fences%%
  • %%Maintain ponds and create new ones%%
  • %%Leave wet corners of field rather than draining them%%
  • %%Plant native trees in areas of low species diversity%%
  • %%Reduce use of pesticides%%
  • %%Use organic fertilisers%%
  • %%Use crop rotation, including a nitrogen fixing crop%%
  • %%Use intercropping to control weeds rather than herbicides%%
  • %%Create natural meadows and use hay rather than grass for silage%%
  • %%Introduce conservation areas%%