Effects of sea urchin grazing on seagrass (Thalassodendron ciliatum) beds of a Kenyan lagoon

Alcoverro, Teresa; Mariani, Simone

doi:10.3354/meps226255

Cited by 75 publications

(60 citation statements)

References 22 publications

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“…The average density of Tripneustes gratilla at our research location (1.55 ± 0.07 m -2 ) was comparable with densities found in other Indo-Pacific meadows (Klumpp et al 1993, Alcoverro & Mariani 2002. Combining the observed T. gratilla density at the research location with the estimated grazing rate under natural conditions, we calculated an urchin population consumption rate of 1.28 g DW leaf m -2 d -1…”

Section: Discussionmentioning

confidence: 85%

“…In the tropical Indo-Pacific region, sea urchins are widely present in seagrass meadows (Klumpp et al 1993, Alcoverro & Mariani 2002. Sea urchin grazing ABSTRACT: We studied sea urchin Tripneustes gratilla herbivory in a meadow of co-occurring seagrass species Thalassia hemprichii (climax species), Halodule uninervis and Cymodocea rotundata (colonizing species) to determine effects of sea urchins on seagrass biomass and species composition, to quantify herbivory rate and to determine the role of urchins in the nitrogen (N) cycle.…”

Section: Introductionmentioning

confidence: 99%

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In situ quantification of Tripneustes gratilla grazing and its effects on three co-occurring tropical seagrass species

Vonk¹,

Pijnappels²,

Stapel³

2008

Mar. Ecol. Prog. Ser.

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Section: Discussionmentioning

confidence: 85%

Section: Introductionmentioning

confidence: 99%

In situ quantification of Tripneustes gratilla grazing and its effects on three co-occurring tropical seagrass species

Vonk¹,

Pijnappels²,

Stapel³

2008

Mar. Ecol. Prog. Ser.

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“…These features, 2 known as feeding-fronts, generally occur at the boundary between grazed and ungrazed habitat (Dean et al, 1984;Scheibling et al, 1999;Alcoverro, 2002;4 Gagnon et al, 2004). The fronts propagate slowly towards the ungrazed region.…”

Section: Introductionmentioning

confidence: 99%

Sea-urchin feeding fronts

Abraham¹

2007

Ecological Complexity

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Sea urchin feeding fronts are a striking example of spatial pattern formation in an ecological system. If it is assumed that urchins are asocial, and that they move randomly, then the formation of these dense fronts is an apparent paradox. The key lies in observations that urchins move further in areas where their algal food is less plentiful. This naturally leads to the accumulation of urchins in areas with abundant algae. If urchin movement is represented as a random walk, with a step size that depends on algal concentration, then their movement may be described by a Fokker-Planck diffusion equation. For certain combinations of algal growth and urchin grazing, travelling wave solutions are obtained. Two dimensional simulations of urchin algal dynamics show that an initially uniformly distributed urchin population, grazing on an alga with a smoothly varying density, may form a propagating front separating two sharply delineated regions. On one side of the front algal density is uniformly low, and on the other side of the front algal density is uniformly high. Bounds on when stable fronts will form are obtained in terms of urchin density and grazing, and algal growth.

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“…Sea urchin is also a well known seagrass herbivore in the Western Indian Ocean and a few cases of overgrazing of seagrass beds has been reported from Jamaica (Camp et al, 1973), Florida USA (Rose et al, 1999), Gulf of Mexico and the Caribbean (Greenway, 1995;Heck and Valentine, 1995) and Kenya (Alcoverro and Mariani, 2002). However, their occurrence and distribution in the seagrass meadows were very much limited though they were found in reef flats of Lakshadweep atolls.…”

Section: Resultsmentioning

confidence: 99%

Turtle herbivory in the seagrass ecosystems in the Lakshadweep atolls: concerns and need for conservation measures

Kaladharan¹,

Saidkoya²,

Kunhikoya³

et al. 2013

J. Mar. Biol. Ass. India

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Green turtles and turtle grass are interdependent in the atoll ecosystems of Lakshadweep as green turtles are herbivores and the latter are being consumed by the turtles. Since the herbivore is being protected by legislation, their herbivory on turtle grass is uncontrolled and had resulted in near total wiping of seagrass meadows. This case study was made from Agatti atoll in detail and the status of seagrass meadows in three neighboring atolls. The present communication stresses the need for the earliest restoration and to conserve the seagrass meadows from being destroyed by the increasing population of green turtles which is essential for the very existence of turtles itself in Lakshadweep Sea.

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Effects of sea urchin grazing on seagrass (Thalassodendron ciliatum) beds of a Kenyan lagoon

Cited by 75 publications

References 22 publications

In situ quantification of Tripneustes gratilla grazing and its effects on three co-occurring tropical seagrass species

In situ quantification of Tripneustes gratilla grazing and its effects on three co-occurring tropical seagrass species

Sea-urchin feeding fronts

Turtle herbivory in the seagrass ecosystems in the Lakshadweep atolls: concerns and need for conservation measures

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