Configuration of small patch reefs and population abundance of a resident reef fish in a complex coral reef landscape

Shibuno²

2009

Self Cite

Small patch reefs can harbor many reef fishes because most fishes have a drifting larval phase to randomly disperse over patchy habitats. We examined the species-area relationship (SAR) of damselfish (Pomacentridae) assemblages over 84 small patch reefs (0.05-45.4 m 2 ) using an enlarged section of a high-resolution color aerial photograph as a field map (1/2500) in a shallow coral reef shore zone (<2 m deep, 3.6 ha, Shiraho Reef, Ishigaki Island, Japan). This study confirmed that the logarithmic function is better than other functions (including the power function) to explain the SAR in this scale. Actual species richness (24) over the entire study site was much higher than the species richness (15.4) extrapolated from the regression line in semi-log space. Better estimates were obtained using random placement models and computer simulations. These results suggest that several small patch reefs are likely to have higher species richness than a single large reef of equivalent area at the study site. The total number of individuals of the four most abundant territorial herbivores increased almost linearly with patch reef area, but that of other species roughly increased with the square root of the area. While no territorial species were found in the smallest reefs, the large territorial herbivore, Hemiglyphidodon plagiometopon, was abundant and had negative effects on species richness in large reefs. Although the well-known single-large-or-several-small (SLOSS) debate has largely been settled, this dichotomy can be important in places where territorial herbivores do not occupy the smallest reefs.

Section: Species-area Relationship On a Very Fine Scalementioning

confidence: 91%

The effect of patch reef size on fish species richness in a shallow coral reef shore zone where territorial herbivores are abundant

Shibuno²

2009

Self Cite

“…The field study was conducted between September 2003 and 2006 in Shiraho Reef, Ishigaki Island (24°22¢N, 124°15¢E), Okinawa, Japan (Kobayashi and Hattori 2006;Hattori and Kobayashi 2007;Tamura et al 2007). We used a large-sized aerial photograph (92 · 92 cm 2 ), which was enlarged from the original negative of the aerial color photograph of Shiraho Reef (23 · 23 cm 2 , OKC-94-13, 1/10,000, 95 Ishigaki C15-34, Geographical Survey Institute, Ministry of Land, Infrastructure and Transport, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…However, those cannot cover seascape composition and the spatial distribution patterns of individuals, especially in low-density species. Hattori and Kobayashi (2007) developed a simple technique to incorporate the fine-scale seascape composition in a 3-ha field survey, including areas of habitat patches and habitat use by the giant sea anemone (Entacmaea quadricolor), which hosts anemonefish (Amphiprion frenatus), in shallow back reefs. In their study, they used an enlarged section of a high-resolution color aerial photograph (less than 0.1 m) to produce an accurate seascape map (equivalent to 1/2,500 scale or more).…”

Section: Introductionmentioning

confidence: 99%

Incorporating fine‐scale seascape composition in an assessment of habitat quality for the giant sea anemone Stichodactyla gigantea in a coral reef shore zone

Kobayashi²

2008

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Habitat loss due to land reclamation often occurs in sandy coral reef shore zones. The giant sea anemone Stichodactyla gigantea, which harbors the false clown anemonefish Amphiprion ocellaris, both of which are potentially flagship species, inhabit these places. To assess habitat quality for S. gigantea, we examined correlative associations between the number and the body size of S. gigantea and the amount of habitat types in fine-scale seascape composition quantified from an enlarged section of a high-resolution (1/2,500) color aerial photograph of the shallow shore zone of Shiraho Reef, Ishigaki Island, Japan. This study confirmed that anemones were most abundant at the edges of dense seagrass beds characterized by shallow sandy bottoms, rock beds, and sparse seagrass beds, while they were less abundant in coral patch reefs. However, anemones inhabiting coral patch reefs were significantly larger and their rate of disappearance over 3 years was lower than those inhabiting other habitats. This suggests that coral patch reefs may be more suitable habitats supporting larger animals and greater persistence of S. gigantea. The visual census techniques applied here, combined with aerial photography and image-analysis software, may be useful as a simple analytical tool for local assessment of suitable habitats for relatively small-bodied marine fauna in shallow-water seascapes.

“…Hattori and Shibuno (2010) investigated species richness and abundance of individuals of damselfishes among 84 small patch reefs and found that abundance of anemonefish Amphiprion frenatus was most positively correlated to damselfish species richness. In addition, Hattori and Kobayashi (2007) reported that total area of dark-colored patch reefs that were detected on aerial images reflects total number of A. frenatus, although they used analog type aerial photographs and did not distinguish tall patch reefs (>1.5 m in height) from the dark-colored patch reefs. The objective of the present study was to examine whether total area of tall patch reefs (>1.5 m in height) that are detectable on stereoscopic aerial images, as well as total area of dark-colored patch reefs that are detectable on ordinary aerial images, can be used for habitat quality assessment of the anemonefish.…”

Section: Introductionmentioning

confidence: 99%

“…The objective of the present study was to examine whether total area of tall patch reefs (>1.5 m in height) that are detectable on stereoscopic aerial images, as well as total area of dark-colored patch reefs that are detectable on ordinary aerial images, can be used for habitat quality assessment of the anemonefish. Total area of dark-colored patch reefs can be compared with the results of Hattori and Kobayashi (2007). Underwater observations on patch reefs were also conducted to confirm relationships between anemonefish abundance and total area of patch reefs.…”

Section: Introductionmentioning

confidence: 99%

Aerial images can detect 3D small patch reefs that are potential habitats for anemonefish Amphiprion frenatus

2017

Self Cite

Patchy habitats often enhance species coexistence and, consequently, abundance of each species. The present study examined two indicators of potential habitats for anemonefish Amphiprion frenatus: total area of dark-colored patch reefs that are detectable on an aerial image with image analysis software, and total area of tall patch reefs (>1.5 m in height) that are detectable on stereoscopic aerial images with a stereoscope. Relationships between patch reef area and anemonefish abundance, as estimated by number of host anemone Entacmaea quadricolor, were investigated at Shiraho Reef, Ishigaki Island, Japan. Total number of anemones was not correlated with total area of tall patch reefs but was highly correlated with total area of darkcolored patch reefs. Underwater observations confirmed that upper surface of tall patch reefs often involved bare substratum, whereas dark-colored patch reefs did not include this substratum. Because reef area approximately reflected reef volume within shallow back reefs, total area of dark-colored patch reefs that are detectable by aerial photography will reflect total volume of reef fish habitat. The present study suggests that aerial photography with a drone can provide a useful predictor of reef fish abundance.