Grimsditsch et al Pemba Resilience Survey 2009 low res
Grimsditsch et al Pemba Resilience Survey 2009 low res.pdf Grimsditsch et al Pemba Resilience Survey 2009 low res.pdf
Detailed Results 4 Detailed Results Due to the complex datasets in this study, results and discussion will be presented together in numbered sections for each dataset, with more synthetic discussion and findings presented in section 3. 4.1 Benthic cover % Cover 100 90 80 70 60 50 40 30 20 10 0 All benthic types Benthic cover for all sites in February 2009 Algal turf (28%) and hard coral (23%) are dominant substrate types in the sites surveyed with sand (18%) and rubble (12%) also making up an important part of the substrate. Soft coral (4%) and coralline algae (2%) are minor components, while macroalgae cover 9% of the benthos. % cover 100 90 80 70 60 50 40 30 20 10 0 Hard coral Soft coral Other inverts Macro-algae Halimeda Coralline algae Bare substrate Rubble Sand Dead standing coral Recently dead coral Unidentified Turf algae No-take zone Reserve Unprotected Benthic cover by level of protection Sites are classified by level of protection, either in the no-take zone (Misali), in the reserve or unprotected (Msuka Bay). The no-take zone site (86%) has a much higher coral cover compared to the reserve (30%) and unprotected areas (29%) that have similar hard coral cover. The no-take zone site (1%) has very little algal turf, while the reserve sites (31%) and unprotected area have similarly high algal turf covers. The unprotected site has the highest macro-algal cover (33%) while the reserve sites have the highest sand (26%) and rubble (15%) cover % Cover 120 100 80 60 40 Hard coral cover by site Hard coral cover varied greatly from 86% in Misali (no-take zone) to 3% in Paradise Reef and 5% in Fundo Outer, two highly degraded sites. 20 0 Misali Mandela Wall Manta Point Fundo Inner Msuka Bay The Hole Njao Gap Kokota Fundo Lagoon Swiss Reef Simba Wall Fundo Outer Paradise reef 17
Detailed Results 2.5 50 Fleshy algae % cover 2.0 1.5 1.0 0.5 % cover Height 45 40 35 30 25 20 15 10 Height (cm) These data were recorded in 1 m 2 quadrats along transects. Algae were identified to genus level and percentage cover and algal frond height were recorded. Algal fronds were generally long, varying from 1 to 44 cm depending on genus and 1 to 11 cm depending on site, indicating low levels of herbivory and little control of the algal population. % cover 0.0 40.0 35.0 30.0 25.0 20.0 15.0 10.0 5.0 0.0 Dictyota Cyanophyta Sargassum Jania Caulerpa Bryopsis Halimeda Symploca Turbinaria Boergesenisa Ventricaria Lyngbia Wurdemannia % cover Height Msuka Bay Swiss Njao Gap Fundo Inner Mandela Fundo Outer Simba Paradise Kokota Chaetomorpha Fundo Lagoon Crouania Chlordesmis Padina Misali The Hole 5 0 12 10 8 6 4 2 0 Height (cm) Dictyota, Sargassum, both brown algae, and Jania, a red algae, are the most common macro-algae genera found on Pemba’s reefs, with other genera only present in small abundance. Cyanophyta, which are bluegreen or cyanobacteria that photosynthesise, were also relatively common. Cyanophyta are nitrogenfixers, and their presence often indicates elevated nutrient levels in the water. They were present at all sites except for the three most northern sites – The Hole, Simba Wall and Swiss Reef. Msuka Bay has the highest algal cover with the longest fronds and is dominated by Sargassum, a brown macroalgae with long fronds that is often indicative of low herbivory. Msuka Bay is the most northern site, in a bay sheltered by Kundeni and Funguni reefs but still relatively exposed to winds and higher wave energy from the northwest. 18
- Page 1 and 2: Coral Reef Resilience Assessment of
- Page 3 and 4: Coral Reef Resilience Assessment of
- Page 6 and 7: Executive Summary 1 Executive Summa
- Page 8 and 9: Executive Summary 2. Tackle the ove
- Page 10 and 11: The Study coral colony and coral co
- Page 12 and 13: The Study Table 2.1. Sites surveyed
- Page 14 and 15: The Study 7. Resilience indicators
- Page 16 and 17: Major Findings on the site that is
- Page 18 and 19: Major Findings rabbitfish, angelfis
- Page 20 and 21: Major Findings 2. Tackle the overfi
- Page 24 and 25: Detailed Results % coral colonies 1
- Page 26 and 27: Detailed Results 4.2 Coral communit
- Page 28 and 29: Detailed Results 4.3 Coral populati
- Page 30 and 31: Detailed Results Moderate Faviid Su
- Page 32 and 33: Detailed Results 4.4 Crown-of-thorn
- Page 34 and 35: Detailed Results Density 250m2 200
- Page 36 and 37: Detailed Results 4.6 Resilience ind
- Page 38 and 39: Detailed Results Influence of resil
- Page 40 and 41: Detailed Results Fundo Lagoon Msuka
- Page 42: INTERNATIONAL UNION FOR CONSERVATIO
D<strong>et</strong>ailed Results<br />
2.5<br />
50<br />
Fleshy <strong>al</strong>gae<br />
% cover<br />
2.0<br />
1.5<br />
1.0<br />
0.5<br />
% cover<br />
Height<br />
45<br />
40<br />
35<br />
30<br />
25<br />
20<br />
15<br />
10<br />
Height (cm)<br />
These data were recorded in<br />
1 m 2 quadrats <strong>al</strong>ong<br />
transects. Algae were<br />
identified to genus level and<br />
percentage cover and <strong>al</strong>g<strong>al</strong><br />
frond height were recorded.<br />
Alg<strong>al</strong> fronds were gener<strong>al</strong>ly<br />
long, varying from 1 to 44<br />
cm depending on genus and<br />
1 to 11 cm depending on<br />
site, indicating <strong>low</strong> levels of<br />
herbivory and little control of<br />
the <strong>al</strong>g<strong>al</strong> population.<br />
% cover<br />
0.0<br />
40.0<br />
35.0<br />
30.0<br />
25.0<br />
20.0<br />
15.0<br />
10.0<br />
5.0<br />
0.0<br />
Dictyota<br />
Cyanophyta<br />
Sargassum<br />
Jania<br />
Caulerpa<br />
Bryopsis<br />
H<strong>al</strong>imeda<br />
Symploca<br />
Turbinaria<br />
Boergesenisa<br />
Ventricaria<br />
Lyngbia<br />
Wurdemannia<br />
% cover<br />
Height<br />
Msuka Bay<br />
Swiss<br />
Njao Gap<br />
Fundo Inner<br />
Mandela<br />
Fundo Outer<br />
Simba<br />
Paradise<br />
Kokota<br />
Cha<strong>et</strong>omorpha<br />
Fundo Lagoon<br />
Crouania<br />
Chlordesmis<br />
Padina<br />
Mis<strong>al</strong>i<br />
The Hole<br />
5<br />
0<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Height (cm)<br />
Dictyota, Sargassum, both<br />
brown <strong>al</strong>gae, and Jania, a<br />
red <strong>al</strong>gae, are the most<br />
common macro-<strong>al</strong>gae<br />
genera found on <strong>Pemba</strong>’s<br />
reefs, with other genera only<br />
p<strong>res</strong>ent in sm<strong>al</strong>l abundance.<br />
Cyanophyta, which are bluegreen<br />
or cyanobacteria that<br />
photosynthesise, were <strong>al</strong>so<br />
relatively common.<br />
Cyanophyta are nitrogenfixers,<br />
and their p<strong>res</strong>ence<br />
often indicates elevated<br />
nutrient levels in the water.<br />
They were p<strong>res</strong>ent at <strong>al</strong>l<br />
sites except for the three<br />
most northern sites – The<br />
Hole, Simba W<strong>al</strong>l and Swiss<br />
Reef.<br />
Msuka Bay has the highest<br />
<strong>al</strong>g<strong>al</strong> cover with the longest<br />
fronds and is dominated by<br />
Sargassum, a brown macro<strong>al</strong>gae<br />
with long fronds that is<br />
often indicative of <strong>low</strong><br />
herbivory. Msuka Bay is the<br />
most northern site, in a bay<br />
sheltered by Kundeni and<br />
Funguni reefs but still<br />
relatively exposed to winds<br />
and higher wave energy<br />
from the northwest.<br />
18
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