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The influence of habitat structural complexity on invertebrate diversity: A comparison between an impacted and a pristine coral reef

de Beer, Michelle (2013) BIOM01 20122
Degree Projects in Biology
Abstract
Abstract

Habitat complexity is shown to be an important driver of invertebrate diversity on impacted coral reefs when the diversity supported by a comparative unit of habitat complexity is compared to that of a pristine coral reef. The more structurally complex pristine reef does not support the conventionally expected greatest amount of diversity, instead an upper limit threshold to habitat complexity is observed. These findings demonstrate the importance of structural complexity on coral reefs to the associated invertebrate communities and marks habitat complexity as a factor to consider in coral reef conservation planning.

Popular science summary:

Conserving Complex Coral

The increase in biodiversity related to the increase... (More)
Abstract

Habitat complexity is shown to be an important driver of invertebrate diversity on impacted coral reefs when the diversity supported by a comparative unit of habitat complexity is compared to that of a pristine coral reef. The more structurally complex pristine reef does not support the conventionally expected greatest amount of diversity, instead an upper limit threshold to habitat complexity is observed. These findings demonstrate the importance of structural complexity on coral reefs to the associated invertebrate communities and marks habitat complexity as a factor to consider in coral reef conservation planning.

Popular science summary:

Conserving Complex Coral

The increase in biodiversity related to the increase in habitat complexity is generally acknowledged. More structure provides more resources, habitats and niches. What better habitat can be chosen to study the importance of this pattern, than coral reefs? In light of the current global state of coral reef habitats being greatly impacted the importance of this pattern is significant in conservation efforts.

So how can we measure habitat complexity and its effects on biodiversity? By using the Habitat Assessment Score (HAS) method habitat complexity can be given a value (min. = 6, max. = 30). This HAS value combines six factors that contribute to complexity. After establishing the complexity of a quadrant on a reef the biodiversity is determined by counting and identifying organisms. This data is used to calculate diversity indices. Finally a ratio can be established to indicate the amount of biodiversity supported by a set level of complexity.

In my study I only consider invertebrate diversity and I collected data from two reefs in the Wakatobi Marine National Park, Indonesia. A comparison was made between these reefs as one (Sampela reef) was very impacted by destructive fishing practices and additional human activity, and the other (Hoga reef) was more conserved and in a somewhat pristine state. The range of HAS values on Sampela is 12 – 27 and on Hoga it is 17 – 28. The multivariate analyses of variance (MANOVA) results, done to test the difference in diversity between the reefs and the various complexity levels, were not significant. Non-metric multi-dimensional scaling (NMMDS) was used to group samples with the most similar diversity; and revealed that the impacted reef and the pristine reef where not very similar. This is further supported by the results from a cluster analysis. The cluster analysis also revealed that the diversity supported by the highest and the lowest complexity levels on the pristine reef where very similar. This could indicate that too much complexity could result in less diversity – a type of complexity threshold. Finally a Sign test was done to compare the ratios of biodiversity supported by the set levels of habitat complexity. This test resulted in one significant value for the comparison between the diversity supported by the lowest complexity level on the two reefs, which suggests that habitat complexity is more important to diversity on impacted reefs than on pristine reefs.

Relevance
Should habitat complexity be taken into account when coral reef conservation plans are made? How much complexity can we afford to lose before invertebrate diversity will be adversely affected? My study serves as a basis from which these and related questions can be answered.
Sampela reef could be seen as a future coral reef habitat scenario which we can study before all the reef systems resemble it. This gives coral reef researchers and conservationists a head start.

Advisor: Anders Nilsson
Department of biology - Aquatic Ecology
Degree project 30 credits in Marine Ecology 2012/13
Lund University (Less)
Please use this url to cite or link to this publication:
author
de Beer, Michelle
supervisor
organization
course
BIOM01 20122
year
type
H2 - Master's Degree (Two Years)
subject
language
English
id
3910740
date added to LUP
2013-06-27 11:51:22
date last changed
2013-06-27 11:51:22
@misc{3910740,
  abstract     = {Abstract

Habitat complexity is shown to be an important driver of invertebrate diversity on impacted coral reefs when the diversity supported by a comparative unit of habitat complexity is compared to that of a pristine coral reef. The more structurally complex pristine reef does not support the conventionally expected greatest amount of diversity, instead an upper limit threshold to habitat complexity is observed. These findings demonstrate the importance of structural complexity on coral reefs to the associated invertebrate communities and marks habitat complexity as a factor to consider in coral reef conservation planning.

Popular science summary:

Conserving Complex Coral

The increase in biodiversity related to the increase in habitat complexity is generally acknowledged. More structure provides more resources, habitats and niches. What better habitat can be chosen to study the importance of this pattern, than coral reefs? In light of the current global state of coral reef habitats being greatly impacted the importance of this pattern is significant in conservation efforts. 

So how can we measure habitat complexity and its effects on biodiversity? By using the Habitat Assessment Score (HAS) method habitat complexity can be given a value (min. = 6, max. = 30). This HAS value combines six factors that contribute to complexity. After establishing the complexity of a quadrant on a reef the biodiversity is determined by counting and identifying organisms. This data is used to calculate diversity indices. Finally a ratio can be established to indicate the amount of biodiversity supported by a set level of complexity. 

In my study I only consider invertebrate diversity and I collected data from two reefs in the Wakatobi Marine National Park, Indonesia. A comparison was made between these reefs as one (Sampela reef) was very impacted by destructive fishing practices and additional human activity, and the other (Hoga reef) was more conserved and in a somewhat pristine state. The range of HAS values on Sampela is 12 – 27 and on Hoga it is 17 – 28. The multivariate analyses of variance (MANOVA) results, done to test the difference in diversity between the reefs and the various complexity levels, were not significant. Non-metric multi-dimensional scaling (NMMDS) was used to group samples with the most similar diversity; and revealed that the impacted reef and the pristine reef where not very similar. This is further supported by the results from a cluster analysis. The cluster analysis also revealed that the diversity supported by the highest and the lowest complexity levels on the pristine reef where very similar. This could indicate that too much complexity could result in less diversity – a type of complexity threshold. Finally a Sign test was done to compare the ratios of biodiversity supported by the set levels of habitat complexity. This test resulted in one significant value for the comparison between the diversity supported by the lowest complexity level on the two reefs, which suggests that habitat complexity is more important to diversity on impacted reefs than on pristine reefs.

Relevance
Should habitat complexity be taken into account when coral reef conservation plans are made? How much complexity can we afford to lose before invertebrate diversity will be adversely affected? My study serves as a basis from which these and related questions can be answered.
Sampela reef could be seen as a future coral reef habitat scenario which we can study before all the reef systems resemble it. This gives coral reef researchers and conservationists a head start. 

Advisor: Anders Nilsson 
Department of biology - Aquatic Ecology
Degree project 30 credits in Marine Ecology 2012/13
Lund University},
  author       = {de Beer, Michelle},
  language     = {eng},
  note         = {Student Paper},
  title        = {The influence of habitat structural complexity on invertebrate diversity: A comparison between an impacted and a pristine coral reef},
  year         = {2013},
}