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It is the most practical method to complement the government 's initiative for water conservation . Alien invasive organisms are a widespread problem throughout the region , particularly in closed ecosystems including Lake Victoria and the Western Indian Ocean Islands.Formal protection of Africa 's biodiversity at both national and international levels has been strengthened over the past 30 years , but the paradigm of conservation is now shifting away from protection and preservation and focussing more on sustainable use and sharing of benefits . This aim was terminated by the Villafranca armistice of July 11 , 1859 . In Southern Africa , loss of indigenous knowledge and inadequate protection of intellectual property rights are hampering conservation measures , as are overharvesting ( legal and illegal ) of medicinal plant species , rare and endangered plants , and " trophy " animals and exotic pets . The American Tract Society was the most prolific producer of this type of volume , producing over a million a year by 1850 , with the aim of teaching non-denominational evangelical Christianity . Overall , there may be benefits for agriculture in many temperate zones , where the length of the growing period will increase , costs of overwintering livestock will fall , crop yields may improve and forests may grow faster . Policy makers cannot afford to ignore the need to improve environmental management if the human vulnerability / environmental change circle is to be broken . Also conducted was an environmental campaign entitled Know Your Rights , whose aim was to educate communities about the fact that a clean environment is a right and a prerequisite for healthy living . In Eastern and Southern Africa conflict between user groups over land and resources is the priority issue , resulting from competition between agriculture , pastoralists , and conservation areas , and from complex and inappropriate land tenure policies . The overall impact of these effects will vary by elevation , soil type , crop and other local factors . Many of the lithographic cartoons are anti-clerical in nature , but this example represents the Roman Republic , Roman wolf at her side , heralding the dawn of Italian unity by ringing a bell in the shape of a cap of liberty . Rather than focusing on health-damaging pollution , improved stove and fuel subsidy programmes in the past have been mainly directed toward reducing pressures on forests , improving the efficiency of crop residue utilization , alleviating fuel poverty in urban slums , and reducing the need for gathering fuel . The aim was to clean up the drainage ditches to prevent flooding and ocean surges . This variability , along with the uncertainties of very long-term climate forecasting , especially at the regional level , makes discussion of the effects of climate change on crop production tentative at best .