Population dynamics of coastal forests of Macrocystis pyrifera in Puerto Toro, Isla Navarino, Southern Chile

Santelices, B.; Ojeda, F. Patricio

doi:10.3354/meps014175

Cited by 89 publications

(65 citation statements)

References 12 publications

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“…The qualitative results reported In this study on the dynamics of Laminaria longicruris and L. digitata are consistent with results obtained for other systems. Increased recruitment success with canopy removal has been observed for several species of Laminariales (Black 1974, Hay & South 1979, Santelices et al 1980, IQrkman 1982, Santelices & Ojeda 1984b. In some of those cases adults of a particular species inhibited recruitment of conspecific juveniles.…”

Section: Discussionmentioning

confidence: 98%

Implications of population dynamics and interspecific competition for harvest management of the seaweed Laminaria

Smith¹

1986

Mar. Ecol. Prog. Ser.

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Growth rates and population variables of the seaweeds Laminaria longicruris De la Pylaie and L. digitata (Hudson) Lamouroux were monitored from July 1980 until April 1983 within adjacent harvested and control plots in southwestern Nova Scotia, Canada. Faster growth rates within the harvested plot, relative to the control plot, for new recruits of both species were detected only during the first year following a September 1980 total harvest of both species. Since standing crop had nearly recovered to pre-harvest levels after 1 yr, the increased growth rate was attributed to reduced standing crop during the first year post-harvest. Analysis of the relationship between each species' summer canopy biomass and the density of the most recent year-class developing in the sub-canopy at the same time provided evidence for interspecific competition, and provided parameter estimates for the relationship. A stochastic model of this 2-species interaction using reliable data on growth, recruitment, and mortality predicts long-term persistence of both species in the absence of harvesting, or other disturbances. Following total harvest, L. longicruris is initially more abundant than L. digitata, but an increasing canopy of L. digitata diminishes the dominance of L. longicruris over a period of 3 to 5 yr.Annual harvesting of only the canopy of L. longicruris (a practical and perhaps technically preferable strategy) produces only 4 % of the yield for a total annual harvest. Annual harvesting of the canopy of L. longicruris plus L. digitata produces only 11 % of the yield for a total annual harvest. These lower yields result from a large decrease in L. longicruris growth rate with increased density. This feature diminishes the effectiveness of removing L. digitata to reduce competition with faster growing L.longicruris. The need for controlled and monitored experimental harvests to evaluate these predictions is discussed, as is the need for more functional analyses of seaweed systems.

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Section: Discussionmentioning

confidence: 98%

Implications of population dynamics and interspecific competition for harvest management of the seaweed Laminaria

Smith¹

1986

Mar. Ecol. Prog. Ser.

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“…Field observations and photographic evidence of the non-removal transect revealed no major change in canopy cover from September 1979 to July 1980 other than a reduction of the deepest end of the belt during winter (Santelices and Ojeda, 1983). During that time canopy surface cover values in the non-removal area ranged from 98 to 95 %.…”

Section: Experimental Treatmentsmentioning

confidence: 97%

“…However, losses of M. pyrifera individuals is a naturally occurring phenomenon in these forests where naturally cleared spots can reach several dozen meters in diameter (Santelices and Ojeda, 1983). Examination of the understory vegetation in such areas indicated only slight modifications in community structure as compared with the vegetation occurring underneath the M. pyn'fera canopy.…”

Section: Introductionmentioning

confidence: 99%

“…A detailed account of the geographic and climatic conditions as well as the structure of these forests of Macrocystis pyrifera has been reported by Santelices and Ojeda (1983). The forests of M. pyrifera are narrow, sheltered, coastal belts quite homogeneous in canopy cover, quite regular in size and distribution pattern of the M. pyrifera individuals, with relatively homogeneous substratum distribution down to 8 m depth and with several strata of algal vegetation.…”

Section: Study Sitementioning

confidence: 99%

“…A comparison of irradiance values between the areas with and without canopy (using a Li-cor Model LI-185 quantum meter) performed in May 1980 (Santelices and Ojeda, 1983) indicated the Macrocystis pyrifera canopy could reduce subsurface light intensities to between one seventh to one tenth that found at the same depth without canopy.…”

Section: Experimental Treatmentsmentioning

confidence: 99%

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Effects of canopy removal on the understory algal community structure of coastal forests of Macrocystis pyrifera from southern South America

Santelices¹,

Ojeda²

1984

Mar. Ecol. Prog. Ser.

Self Cite

107

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Communities with similar physiognomy often have been expected to show similar ecological responses to experimental manipulations. This is the case in geographically disjunct communities of Macrocystis pyrifera, most of which have been described as showing notoriously similar patterns of vegetational stratification. Comparison of the ecological responses of the second and third vegetational strata to the removal of the floating canopy of M. pyrifera in forests in southern Chile point to differences with equivalent experiments performed in the northern Pacific. In southern Chile the second stratum which is formed by Lessonja flavicans decreases in biomass representation after removal of the floating M. pMfera canopy. The third stratum contains a number of fugitive species which are replaced by a numerically similar group of fugitive species after removal of the floating M. pyrifera canopy. The presence of perennial species in the third stratum seem unaffected by light changes resulting either from seasonal variation or from removal of the floating canopy. Total number of understory algal species in the forests from southern Chile is lower compared to giant kelp forests in California. Canopy removal does not significantly change the total number of species, although it changes the specific component in each experimental area. Thus, the ecological response of the understory algal community to the removal of the floating canopy of M. pyr'fera in southern Chile seems less dramatic than that which has been described for similar communities in the North Pacific Ocean.

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Ecosystem effects of fishing in kelp forest communities

Tegner

2000

ICES Journal of Marine Science

234

188

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Kelp forests, highly diverse cold water communities organized around the primary productivity and physical structure provided by members of the Laminariales, support a variety of fisheries, and the kelp itself is harvested for alginates. Worldwide, these communities generally share susceptibility to destructive overgrazing by sea urchins. The impact of sea-urchin grazing is governed by the ratio between food availability and grazing pressure, thus factors affecting the abundance of both urchins and kelps are central to ecosystem integrity. Some kelp ecosystems share a second generality, the association of exploitation of various urchin predators with destructive levels of urchin grazing, leading to cascading implications for other species dependent on the productivity and habitat provided by the kelps. Competition between abalones and sea urchins also affects some kelp communities. These ecosystem-structuring processes are complicated by a variety of bottom-up and top-down factors, including variability in ocean climate affecting kelp productivity and recruitment of key species, and echinoid disease. Potential ecosystem effects of fisheries for predators, abalones, sea urchins, and kelps are reviewed biogeographically. Given the hundreds to thousands of years that many nearshore marine ecosystems have been exploited, no-take marine reserves may be the only way to determine the true ecosystem effects of fishing. International Council for the Exploration of the Sea

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Population dynamics of coastal forests of Macrocystis pyrifera in Puerto Toro, Isla Navarino, Southern Chile

Cited by 89 publications

References 12 publications

Implications of population dynamics and interspecific competition for harvest management of the seaweed Laminaria

Implications of population dynamics and interspecific competition for harvest management of the seaweed Laminaria

Effects of canopy removal on the understory algal community structure of coastal forests of Macrocystis pyrifera from southern South America

Ecosystem effects of fishing in kelp forest communities

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