scholarly journals A unified model explains commonness and rarity on coral reefs

2017 ◽  
Vol 20 (4) ◽  
pp. 477-486 ◽  
Author(s):  
Sean R. Connolly ◽  
Terry P. Hughes ◽  
David R. Bellwood
Keyword(s):  
Coral Reefs ◽  
Unified Model ◽  
Commonness And Rarity

scholarly journals Volatility in coral cover erodes niche structure, but not diversity, in reef fish assemblages

2021 ◽  
Author(s):  
Cheng-Han Tsai ◽  
Hugh PA Sweatman ◽  
Löic M Thibaut ◽  
Sean R Connolly
Keyword(s):  
Coral Reefs ◽  
Reef Fish ◽  
Fish Assemblages ◽  
Environmental Gradients ◽  
Coral Cover ◽  
Species Abundance ◽  
Alpha Diversity ◽  
Deterministic Processes ◽  
Diversity Systems ◽  
Commonness And Rarity

Environmental fluctuations are becoming increasingly volatile in many ecosystems, highlighting the need to better understand how stochastic and deterministic processes shape patterns of commonness and rarity, particularly in high-diversity systems like coral reefs. Here, we analyse reef fish time-series across the Great Barrier Reef to show that approximately 75% of the variance in relative species abundance is attributable to deterministic, intrinsic species differences. Nevertheless, the relative importance of stochastic factors is markedly higher on reefs that have experienced stronger coral cover volatility. By contrast, alpha diversity and species composition are independent of coral cover volatility but depend on environmental gradients. Our findings imply that increased environmental volatility on coral reefs erodes assemblage's niche structure, an erosion that is not detectable from static measures of biodiversity.

Pemetaan Pulau Kecil Gelasa Kabupaten Bangka Tengah

2019 ◽  
Vol 2 (1) ◽  
pp. 11-14
Author(s):  
Wahyu Adi
Keyword(s):  
Coral Reefs ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Image Interpretation ◽  
Vegetation Coverage ◽  
Small Island ◽  
Shallow Waters ◽  
Small Islands ◽  
Seagrass Beds ◽  
Cover Density

Pulau Kecil Gelasa merupakan daerah yang belum banyak diteliti. Pemetaan ekosistem di pulau kecil dilakukan dengan bantuan citra Advanced Land Observing Satellite (ALOS). Penelitian terdahulu diketahui bahwa ALOS memiliki kemampuan memetakan terumbu karang dan padang lamun di perairan dangkal serta mampu memetakan kerapatan penutupan vegetasi. Metode interpretasi citra menggunakan alogaritma indeks vegetasi pada citra ALOS yaitu NDVI (Normalized Difference Vegetation Index), serta pendekatan Lyzengga untuk mengkoreksi kolom perairan. Hasil penelitian didapatkan luasan Padang Lamun di perairan dangkal 41,99 Ha, luasan Terumbu Karang 125,57 Ha. Hasil NDVI di daratan/ pulau kecil Gelasa untuk Vegetasi Rapat seluas 47,62 Ha; luasan penutupan Vegetasi Sedang 105,86 Ha; dan penutupan Vegetasi Jarang adalah 34,24 Ha.   Small Island Gelasa rarely studied. Mapping ecosystems on small islands with the image of Advanced Land Observing Satellite (ALOS). Previous research has found that ALOS has the ability to map coral reefs and seagrass beds in shallow water, and is able to map vegetation cover density. The method of image interpretation uses the vegetation index algorithm in the ALOS image, NDVI (Normalized Difference Vegetation Index), and the Lyzengga approach to correct the water column. The results of the study were obtained in the area of Seagrass Padang in the shallow waters of 41.99 ha, the area of coral reefs was 125.57 ha. NDVI results on land / small islands Gelasa for dense vegetation of 47.62 ha; area of Medium Vegetation coverage 105.86 Ha; and the coverage of Rare Vegetation is 34.24 Ha.

Drivers of herbivory on coral reefs: species, habitat and management effects

2016 ◽  
Vol 554 ◽  
pp. 129-140 ◽  
Author(s):  
KL Nash ◽  
RA Abesamis ◽  
NAJ Graham ◽  
EC McClure ◽  
E Moland
Keyword(s):  
Coral Reefs ◽  
Management Effects
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