Difference in
degree of complexity of habitat structures and their effects on
biodiversity in various back reef habitats.

Cuison, A. and
Perez, C.

Abstract

This
experiment aimed to show the effects of an addition of habitat
structures of different spatial complexity to three back reef zones
with various degrees of natural complexity. A simple structure (215
cmᶟ)
and a complex structure (862 cmᶟ)
were created in order to show how the difference in area for
inhabitation would affect biodiversity in three distinct environments
within the back reef. After assessing the location, a metric of
comparison was created in order to place the different back reef
environments of sand flat, seagrass, and patch coral into three
categories based on the natural complexity they provide (1-3
respectively). Once the environments were split into the categories,
each was provided with one of each of our simple and complex
structures. The structures at each site were situated linearly 10
meters apart from one another and the three sites were around 20
meters apart. The structures were observed once daily in the morning
and all the species living within the structure, within 2 meters of
the structure and those who visited the structure (>5 seconds)
were recorded. After one week of observations we found that the sand
flat area had the greatest number of inhabitants and the most
immigration of diversity while the patch coral had equal success in
abundance but diversity was only redistributed among the new complex
structure and the naturally occurring complexity of a reef system.
This tells us that in an area lacking all natural complex structures,
organisms will be attracted to and therefore more inclined to inhabit
any additional structure provided. However, in a natural habitat that
is teeming with complexity, organisms have a tendency to congregate
in that one area and are then inclined to move from structure to
structure as opposed to any new diversity migrating in.  

Damsel in structure.