scholarly journals Seascape Configuration Leads to Spatially Uneven Delivery of Parrotfish Herbivory across a Western Indian Ocean Seascape

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 434
Author(s):  
Linda Eggertsen ◽  
Whitney Goodell ◽  
César A. M. M. Cordeiro ◽  
Thiago C. Mendes ◽  
Guilherme O. Longo ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Life Histories ◽  
Spatial Configuration ◽  
Spatial Scales ◽  
Western Indian Ocean ◽  
Habitat Types ◽  
Opposite Pattern ◽  
Seagrass Meadows ◽  
Alternative Habitat ◽  
Mobile Links

Spatial configuration of habitat types in multihabitat seascapes influence ecological function through links of biotic and abiotic processes. These connections, for example export of organic matter or fishes as mobile links, define ecosystem functionality across broader spatial scales. Herbivory is an important ecological process linked to ecosystem resilience, but it is not clear how herbivory relates to seascape configuration. We studied how herbivory and bioerosion by 3 species of parrotfish were distributed in a multi-habitat tropical seascape in the Western Indian Ocean (WIO). We surveyed the abundance of three species with different life histories—Leptoscarus vaigiensis (seagrass species), Scarus ghobban (juvenile-seagrass/adults-reefs) and Scarus rubroviolaceus (reef species) —in seagrass meadows and on reefs and recorded their selectivity of feeding substrate in the two habitats. Herbivory rates for L. vaigiensis and S. ghobban and bioerosion for S. rubroviolaceus were then modelled using bite rates for different size classes and abundance and biomass data along seascape gradients (distance to alternative habitat types such as land, mangrove and seagrass). Bioerosion by S. rubroviolaceus was greatest on reefs far from seagrass meadows, while herbivory rates by S. ghobban on reefs displayed the opposite pattern. Herbivory in seagrass meadows was greatest in meadows close to shore, where L. vaigiensis targeted seagrass leaves and S. ghobban the epiphytes growing on them. Our study shows that ecological functions performed by fish are not equally distributed in the seascape and are influenced by fish life history and the spatial configuration of habitats in the seascape. This has implications for the resilience of the system, in terms of spatial heterogeneity of herbivory and bioerosion and should be considered in marine spatial planning and fisheries management.

Linkage between fish functional groups and coral reef benthic habitat composition in the Western Indian Ocean

2016 ◽  
Vol 98 (2) ◽  
pp. 387-400 ◽  
Author(s):  
Kennedy Osuka ◽  
Marc Kochzius ◽  
Ann Vanreusel ◽  
David Obura ◽  
Melita Samoilys
Keyword(s):  
Coral Reef ◽  
Indian Ocean ◽  
Functional Groups ◽  
Habitat Type ◽  
Western Indian Ocean ◽  
Reef Fishes ◽  
Coralline Algae ◽  
Benthic Habitat ◽  
Habitat Types ◽  
Habitat Composition

Benthic habitat composition is a key factor that structures assemblages of coral reef fishes. However, natural and anthropogenic induced disturbances impact this relationship. This study investigates the link between benthic habitat composition and fish functional groups in four countries in the Western Indian Ocean (WIO). Benthic composition of 32 sites was quantified visually from percentage cover of hard and soft corals, rubble, turf, fleshy and crustose coralline algae. At each site, abundance of 12 coral-associated fish functional groups in 50 × 5 m transects was determined. Cluster analysis characterized reefs based on benthic cover and revealed five habitat types (A, B, C, D and E) typified by decreasing cover of hard corals, increasing cover of turf and/or fleshy algae and differences in benthic diversity. Habitat type A was present in all four countries. Other habitats types showed geographic affiliations: notably Comoros sites clustered in either habitats B or E, northern Madagascar had B, C and D type habitats, whereas sites in central Tanzania and northern Mozambique had habitats D and E. Fish functional groups showed significant linkages with some habitat types. The abundances of corallivores, invertivores, detritivores and grazers were higher in habitat B, whereas planktivores and small excavators showed lower abundances in the same habitat. These linkages between benthic habitat types and fish functional groups are important in informing priority reefs that require conservation and management planning.

scholarly journals Blue Carbon Storage in Tropical Seagrass Meadows Relates to Carbonate Stock Dynamics, Plant–Sediment Processes, and Landscape Context: Insights from the Western Indian Ocean

Ecosystems ◽  
2017 ◽  
Vol 21 (3) ◽  
pp. 551-566 ◽  
Author(s):  
Martin Gullström ◽  
Liberatus D. Lyimo ◽  
Martin Dahl ◽  
Göran S. Samuelsson ◽  
Maria Eggertsen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Carbon Storage ◽  
Western Indian Ocean ◽  
Blue Carbon ◽  
Landscape Context ◽  
Seagrass Meadows

scholarly journals Green turtle diet is dominated by seagrass in the Western Indian Ocean except amongst gravid females

2019 ◽  
Vol 166 (10) ◽  
Author(s):  
Holly J. Stokes ◽  
Jeanne A. Mortimer ◽  
Graeme C. Hays ◽  
Richard K. F. Unsworth ◽  
Jacques-Olivier Laloë ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Green Turtle ◽  
Western Indian Ocean ◽  
Chelonia Mydas ◽  
Breeding Habitat ◽  
Gut Contents ◽  
Seagrass Meadows ◽  
Green Turtles ◽  
The Republic ◽  
Gravid Females

Abstract Green turtles (Chelonia mydas) are key herbivores of tropical and subtropical neritic habitats and play a major role in structuring seagrass meadows. We present the first detailed assessment of green turtle diet in the Western Indian Ocean using the gut contents of salvaged animals from three atolls in the Republic of Seychelles separated from each other by 400–825 km: Cosmoledo (adults, n = 12), Farquhar (adults, n = 33; immature, n = 1) collected in 1982–1983; and Desroches (immatures, n = 8) in 2016–2018. We report the first comparison of the diets of gravid females (n = 17), males (n = 26) and non-breeding females (n = 2) at sites providing both foraging and breeding habitat. Seagrass (mostly Thalassodendron ciliatum) dominated the diet, accounting for 95% of the mean gut content biomass for males and non-breeding females but only 58% for gravid females, alongside relatively large amounts of substrate (14%) and macroalgae (13%). Satellite tracking of post-nesting green turtles from Chagos Archipelago in 2016 located foraging sites at Farquhar Atoll that coincided with capture locations of 26 of the 33 adult turtles sampled there in 1983. In situ surveys of those sites in 2018 revealed extensive nearly monospecific beds of T. ciliatum. The prominence of seagrass in the diet of green turtles and connectivity between foraging and nesting habitats throughout the region illustrate the need to conserve and monitor seagrass habitats of the Western Indian Ocean especially in the context of changing green turtle population densities.

Editorial Introduction

2020 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Editors of the JIOWS
Keyword(s):  
Nineteenth Century ◽  
Indian Ocean ◽  
Western Indian Ocean ◽  
Late Nineteenth Century ◽  
Fourth Volume ◽  
History Of ◽  
The Indian Ocean ◽  
Complex Relationships ◽  
Indian Ocean World ◽  
Shed Light

The editors are proud to present the first issue of the fourth volume of the Journal of Indian Ocean World Studies. This issue contains three articles, by James Francis Warren (Murdoch University), Kelsey McFaul (University of California, Santa Cruz), and Marek Pawelczak (University of Warsaw), respectively. Warren’s and McFaul’s articles take different approaches to the growing body of work that discusses pirates in the Indian Ocean World, past and present. Warren’s article is historical, exploring the life and times of Julano Taupan in the nineteenth-century Philippines. He invites us to question the meaning of the word ‘pirate’ and the several ways in which Taupan’s life has been interpreted by different European colonists and by anti-colonial movements from the mid-nineteenth century to the present day. McFaul’s article, meanwhile, takes a literary approach to discuss the much more recent phenomenon of Somali Piracy, which reached its apex in the last decade. Its contribution is to analyse the works of authors based in the region, challenging paradigms that have mostly been developed from analysis of works written in the West. Finally, Pawelczak’s article is a legal history of British jurisdiction in mid-late nineteenth-century Zanzibar. It examines one of the facets that underpinned European influence in the western Indian Ocean World before the establishment of colonial rule. In sum, this issue uses two key threads to shed light on the complex relationships between European and other Western powers and the Indian Ocean World.

scholarly journals Factors influencing microbial mat composition, distribution and dinitrogen fixation in three western Indian Ocean coral reefs

2012 ◽  
Vol 47 (1) ◽  
pp. 51-66 ◽  
Author(s):  
Loïc Charpy ◽  
Katarzyna A. Palinska ◽  
Raeid M. M. Abed ◽  
Marie José Langlade ◽  
Stjepko Golubic
Keyword(s):  
Indian Ocean ◽  
Coral Reefs ◽  
Western Indian Ocean ◽  
Dinitrogen Fixation ◽  
Microbial Mat ◽  
Composition Distribution ◽  
Factors Influencing

scholarly journals Movement ecology of black marlin Istiompax indica in the Western Indian Ocean

2021 ◽  
Author(s):  
Christoph A. Rohner ◽  
Roy Bealey ◽  
Bernerd M. Fulanda ◽  
Jason D. Everett ◽  
Anthony J. Richardson ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Movement Ecology ◽  
Western Indian Ocean

scholarly journals Post-bleaching mortality of a remote coral reef community in Seychelles, Western Indian Ocean

2019 ◽  
Vol 18 (1) ◽  
pp. 11
Author(s):  
Elena Gadoutsis ◽  
Clare A.K. Daly ◽  
Julie P. Hawkins ◽  
Ryan Daly
Keyword(s):  
Coral Reef ◽  
Indian Ocean ◽  
Western Indian Ocean ◽  
Coral Reef Community ◽  
Reef Community

scholarly journals Variability in the Mozambique Channel Trough and Impacts on Southeast African Rainfall

2020 ◽  
Vol 33 (2) ◽  
pp. 749-765 ◽  
Author(s):  
Rondrotiana Barimalala ◽  
Ross C. Blamey ◽  
Fabien Desbiolles ◽  
Chris J. C. Reason
Keyword(s):  
Indian Ocean ◽  
Austral Summer ◽  
Western Indian Ocean ◽  
Strong Relationship ◽  
Ocean Basin ◽  
Moist Convection ◽  
South Indian Ocean ◽  
Mozambique Channel ◽  
Mascarene High ◽  
South Indian

AbstractThe Mozambique Channel trough (MCT) is a cyclonic region prominent in austral summer in the central and southern Mozambique Channel. It first becomes evident in December with a peak in strength in February when the Mozambique Channel is warmest and the Mascarene high (MH) is located farthest southeast in the Indian Ocean basin. The strength and the timing of the mean MCT are linked to that of the cross-equatorial northeasterly monsoon in the tropical western Indian Ocean, which curves as northwesterlies toward northern Madagascar. The interannual variability in the MCT is associated with moist convection over the Mozambique Channel and is modulated by the location of the warm sea surface temperatures in the south Indian Ocean. Variability of the MCT shows a strong relationship with the equatorial westerlies north of Madagascar and the latitudinal extension of the MH. Summers with strong MCT activity are characterized by a prominent cyclonic circulation over the Mozambique Channel, extending to the midlatitudes. These are favorable for the development of tropical–extratropical cloud bands over the southwestern Indian Ocean and trigger an increase in rainfall over the ocean but a decrease over the southern African mainland. Most years with a weak MCT are associated with strong positive south Indian Ocean subtropical dipole events, during which the subcontinent tends to receive more rainfall whereas Madagascar and northern Mozambique are anomalously dry.

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