Study with the several resources on Docsity
Earn points by helping other students or get them with a premium plan
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Community
Ask the community for help and clear up your study doubts
Discover the best universities in your country according to Docsity users
Free resources
Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors
The amazon rainforest, the largest ecological experiment on earth, and the devastating impact of deforestation on its species diversity. The document also discusses the importance of rainforests in providing essential ecological services and human benefits. Case studies, concepts, and theories related to biogeography and spatial scale, global and regional biogeography, and the dynamics of forest fragments project.
Typology: Slides
1 / 21
This page cannot be seen from the preview
Don't miss anything!
One hectare of rainforest in the Amazon contains more plant species than all of Europe! The Amazon Basin is the largest watershed in the world. The number of fish species in the Amazon River exceeds the total number found in the entire Atlantic Ocean.
While 15% seems modest, the sheer number of species impacted is staggering. The pattern of deforestation has also resulted in extreme habitat fragmentation, making it more difficult to maintain species diversity.
In 1979, habitat fragmentation spurred Thomas Lovejoy to initiate the longest running ecological experiment ever conducted: The Dynamics of Forest Fragments Project (BDFFP). He was guided by The Theory of Island Biogeography, an explanation for the observation that more species are found on large islands than on small islands.
Biogeography is the study of patterns of species composition and diversity across geographic locations.
Concept 17.1: Patterns of species diversity and distribution vary at global, regional, and local spatial scales.
New Zealand has been separated from continental land masses for about 80 million years. Since that time evolution has resulted in unique forests. About 80% of the species are endemic , meaning that they occur nowhere else on Earth.
Regional scale —climate is roughly uniform and the species are bound by dispersal to that region. Regional species pool —all the species contained within a region ( gamma diversity ).
Local scale —equivalent to a community. Species physiology and interactions with other species weigh heavily in the resulting species diversity ( alpha diversity ).
Beta diversity —change in species number and composition, or turnover of species, as one moves from one community type to another. Beta diversity represents the connection between local and regional scales of species diversity.
Wallace is best known, along with Charles Darwin, as the codiscoverer of the principles of natural selection.
But his main contribution was the study of species distributions across large spatial scales.
An important concept in biogeography is the relationship between species number and geographic area. Species–area relationship —species richness increases with increasing area sampled.
Concept 17.3: Regional differences of species diversity are controlled by area and distance due to a balance between immigration and extinction rates.
MacArthur and Wilson developed these observations into a theoretical model, the equilibrium theory of island biogeography.
The number of species on an island depends on a balance between immigration rates and extinction rates.
One of the goals of the Biological Dynamics of Forest Fragments Project (BDFFP) was to study the effects of reserve design on the maintenance of species diversity. They learned that habitat fragmentation had more negative and complicated effects than originally anticipated.
