Official approaches to squatter settlements and the housing of the urban poor have changed over time from policies of clearance and relocation to schemes which promote the involvement of the private sector and nongovernmental organizations in supporting poor residents to improve their own housing and neighborhoods.n this article, the main debates surrounding squatter settlements are outlined, focusing on definitional issues and their geographical distribution. The changing nature of policies toward these settlements is also covered.
Lichen. Lichen is a structure that commonly grows on trees; it is a result of a symbiotic relationship between algae and fungi. The fungus provides a structure that collects water and nutrients that the algae takes advantage of; the algae in turn uses its chlorophyll to produce food for both itself and the fungus.Species of the Trentepohlia genus are commonly found in lichens.he fungus provides a structure that collects water and nutrients that the algae takes advantage of; the algae in turn uses its chlorophyll to produce food for both itself and the fungus. Species of the Trentepohlia genus are commonly found in lichens.
Algae, lichens and moss are non-parasitic plant-like organisms that colonise bark, rock and other hard surfaces. Lichens and algae are often mistaken for a fungal disease but, fortunately, they do not harm plants on which they grow.lgae, lichens and moss are found in damp places, as not only do they need moisture for growth but also for reproduction. Lichens are particularly adaptable as they are able to exist where nutrients, and sometimes water, are scarce. However, they grow only very slowly so, unlike moss and algae, are slow to colonise.