Dynamics Behind Standoff Interactions in Three Reef Sponge Species and the Coral <i>Montastraea cavernosa</i>

Aerts, Lisanne

doi:10.1046/j.1439-0485.2000.00685.x

Cited by 59 publications

(49 citation statements)

References 27 publications

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“…can induce premature release of highly unviable planulae (Henry et al 2003). Aside from diminished reproductive fitness, injured corals also have lower growth rates (Yoshioka & Yoshioka 1991, Meesters et al 1994, and reduced competitive abilities against encroachment from neighboring organisms (Aerts 2000).The fate of the dislodged and fractured sea whips in the present study illustrates the direct negative effect of trawl disturbance on sea whips. Furthermore, trawl disturbance to sea whips often results in a combination of injuries, including abrasion, fracture, and dislodgement (P. Malecha pers.…”

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confidence: 63%

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Response of the sea whip Halipteris willemoesi to simulated trawl disturbance and its vulnerability to subsequent predation

Malecha¹,

Stone²

2009

Mar. Ecol. Prog. Ser.

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The sea whip Halipteris willemoesi occurs in habitats coincident with bottom trawl fisheries in the Gulf of Alaska and Bering Sea and can be damaged by passing trawls. Little is known about the long-term fate of sea whips damaged by trawl gear. Sea whip responses to simulated trawl disturbance were observed in situ over a period of about 1 yr in order to assess delayed mortality from sublethal injuries. Colonies of H. willemoesi were randomly assigned to 3 treatment groups and 1 control group. Treatments were designed to mimic trawl damage including dislodgement, fracture of the axial rod, and soft tissue abrasion. Fifty percent of dislodged colonies demonstrated the ability to rebury their peduncles and recover to an erect position. Most of these colonies eventually became dislodged again without further disturbance and only one was erect at the final observation. None of the fractured colonies were able to repair their axial rods and only one was erect at the experiment's conclusion. Light tissue abrasion caused only minor tissue losses that lessened over time, and all abraded and control colonies remained erect throughout the experiment. Tissue losses among the dislodged and fractured sea whips increased throughout the experimental period and were mainly due to predation by the nudibranch Tritonia diomedea, which appeared to react with a strong scavenging response to sea whips lying on the seafloor. The presence of predators in areas where sea whips are disturbed may exacerbate trawl effects since damaged or dislodged colonies are more vulnerable to predation. 388: 197-206, 2009 entire shelf averaged 2.4% swept annually, but in the Bering Sea and Gulf of Alaska many areas were trawled more than 5 times per year and one area was trawled 17 times per year (Rose & Jorgensen 2005). Similar intensities have been reported for heavily trawled areas on both sides of the Atlantic Ocean (Floderus & Pihl 1990, Auster et al. 1996. KEY WORDS: Trawling · Sea whip · Halipteris willemoesi · Seafloor habitat · Nudibranch · Tritonia diomedea Resale or republication not permitted without written consent of the publisherMar Ecol Prog SerSea whips have a relatively simple morphology consisting of a bulbous basal peduncle (which serves as an anchor in soft sediments) and a vertical rachis or shaft extending distally from the peduncle. An axial rod, composed of magnesium calcite, supports the entire colony, and the rachis is populated with rows of polyps. Ten species of pennatulaceans are known to occur in Alaska (Stone & Shotwell 2007) and size varies considerably among species. Halipteris willemoesi Kölliker, 1870(von Kölliker 1870 can reach heights greater than 300 cm (Stone & Shotwell 2007), while Protoptilum sp. may reach just 35 cm. Sea whips can form dense groves that provide vertical structure to low relief habitats. In Alaska, Stone et al. (2005) found densities at least as high as 16 and 6 m -2 for adult specimens of Protoptilum sp. and H. willemoesi, respectively. In British Columbia, Troffe et al. (2005) f...

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confidence: 63%

Section: Discussionmentioning

confidence: 99%

Response of the sea whip Halipteris willemoesi to simulated trawl disturbance and its vulnerability to subsequent predation

Malecha¹,

Stone²

2009

Mar. Ecol. Prog. Ser.

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“…Thus, in addition to the complex interplay of environmental, physical and temporal factors that affects the success of competitors (Barnes & Rothery 1996), for D. perlucidum the identity of its competitor also had a strong influence in the outcome of border contacts. While the most visible form of spatial competition is direct overgrowth of organisms already occupying space (Aerts 2000), stand offs are a frequent result of border interaction, mainly in intra-phyletic encounters (Karlson 1980, Schmidt & Warner 1986, Bell & Barnes 2003. This kind of interaction contributes greatly to the dynamics of spatial competition and the maintenance of local species richness.…”

Section: Discussionmentioning

confidence: 99%

Effects of competition on sexual and clonal reproduction of a tunicate: the importance of competitor identity

Dias¹,

Delboni²,

Duarte³

2008

Mar. Ecol. Prog. Ser.

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Individual fitness and the structure of marine communities are strongly affected by spatial competition. Among the most common space holders are the colonial ascidians, which have the ability to monopolize large areas of hard substrate, overgrowing most other competitors. The effects of competition on colony growth and on gonad production of the ascidian Didemnum perlucidum were studied in southeastern Brazil by experimentally removing surrounding competitors. Colonies of D. perlucidum competing for space exhibited a growth rate 9 times less than that of colonies that were competitor free. Among the colonies subject to competition, growth rates were unrelated to the percentage of colony border that was free of competitors. However, the identity of the competitor was important in the outcome of border contacts. At the beginning of the experiment, most border encounters of D. perlucidum were with solitary organisms, which in most cases were overgrown. These were progressively replaced by colonial ascidians and bryozoans, resulting mostly in stand-off interactions. Besides reducing asexual growth, spatial competition also affected female gonad production. Colonies free of competitors had a significantly higher proportion of zooids with ovaries. Thus, our findings show that spatial competition reduces both ascidian colony size and gonad production. KEY WORDS: Space competition · Tunicate · ReproductionResale or republication not permitted without written consent of the publisher

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“…Most information regarding sponges as spatial competitors on coral reefs comes from the Caribbean where sponges use a number of mechanisms to compete for space including, the production of toxic secondary metabolites [19,20], variable growth rates [21] and variable growth forms [22]. Comparatively, little information is available for other coral reef regions.…”

Section: Introductionmentioning

confidence: 99%

Patterns of Sponge Abundance Across a Gradient of Habitat Quality in the Wakatobi Marine National Park, Indonesia

Powell¹,

Hepburn²,

Smith³

et al. 2010

TOMBJ

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Abstract:Sponges are important components of reef communities worldwide, fulfilling a number of important functional roles. Habitat degradation caused by the loss of hard corals has the potential to cause increases in sponge abundance and percentage cover as they gain access to resources such as space and food. In this study we compared sponge densities and percentage cover at sites with varying hard coral cover in the Wakatobi Marine National Park, Indonesia (WMNP). We found significant differences in sponge densities at the study sites but no significant difference in sponge densities on different surface angles. Unexpectedly, we also found a weak positive correlation between coral cover and sponge density. This indicates that spatial competition is unlikely to be the most important factor determining sponge abundance in the WMNP. In contrast to sponge density data, we found that sponge percentage cover and hard coral cover were weakly negatively correlated, but found no significant difference in sponge percentage cover between the study sites. Finally, multivariate analysis of the benthic communities at the study sites indicated that while sites with higher coral cover were characterised by coral (proportionally), lower coral cover sites were characterised by algae and sponges. This suggests that although there was no significant difference in sponge percentage cover between the study sites conditions that led to the loss of hard coral at lower quality sites mean that these sites are characterised by sponges and algae rather than by any other groups of benthic organisms.

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Dynamics Behind Standoff Interactions in Three Reef Sponge Species and the Coral Montastraea cavernosa

Cited by 59 publications

References 27 publications

Response of the sea whip Halipteris willemoesi to simulated trawl disturbance and its vulnerability to subsequent predation

Response of the sea whip Halipteris willemoesi to simulated trawl disturbance and its vulnerability to subsequent predation

Effects of competition on sexual and clonal reproduction of a tunicate: the importance of competitor identity

Patterns of Sponge Abundance Across a Gradient of Habitat Quality in the Wakatobi Marine National Park, Indonesia

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