Landscape ecology is the study of how spatial arrangements of habitat affect ecological processes, the abundance of organisms, and the distribution of these organisms. It is the study of the interaction of habitats, vegetation, land use, and wildlife between each other across a vast area composed of various ecosystems. It is important to think of ecology at a large geographic scale, particularly when we are interested in studying metapopulations or when trying to explain processes associated with island biogeography. The broader spatial perspective helps us better understand processes associated with population dynamics and the distribution and diversity of species in a community. There are several main topics relevant to conservation biology:

• Landscape heterogeneity has long been considered a key determinant of biodiversity. Landscape heterogeneity is simply the variation of habitat types, vegetation types, and land uses across a region somewhere between the size of a biome and an ecosystem. The structure of the landscape is composed of patches, corridors, and gaps. When we start considering larger areas of land, perhaps the most obvious observation is that those larger areas contain a greater variety of habitats which subsequently host a greater number of species and ecosystems.
• Species distributed throughout a landscape may become fragmented when suitable habitat is lost which can lead to disjointed populations. The quality of these habitat networks relates to the likelihood that these patches will be used by organisms while traversing through a matrix.  Fragmentation of the landscape into isolated habitat patches of different sizes and shapes influences biodiversity, as well as how habitat corridors and the quality of the matrix between habitat fragments affects patterns of local species richness and species turnover.  Habitat fragmentation often results in lack of food and other resources for species that need them. It also eliminates habitat for species that need large unbroken blocks of habitat.
• Patch size and shape have a huge impact on quality habitat and presence of organisms. The reduced size of habitat patches shrink results in reduced carrying capacity.
• Habitat fragmentation is associated with a decrease in animal population size and increase in their risk of extinction. It is considered one of the greatest threats to tropical biodiversity.  Increasing isolation among subpopulations with increasing distance between patches also means that many species will not migrate long distances across a matrix. If there is no immigration or emigration, then there is no colonization of these patches, and subsequently little or no gene flow. One of the effects of this is that you get all the small population phenomenon, that is loss of genetic diversity, increased inbreeding, no chance of a rescue effect from incoming individuals, increased genetic drift and subsequent fixation of alleles. All together, it means you have a greater risk for local extinction. It also means that the further a patch is from other habitat patches, the lower the species diversity that is expected in it, controlling for size. This is directly related to island biogeography.
  
  

Resources
Principles of Landscape Ecology
Landscape Ecology in Theory and Practice