Life history and viability of a long-lived marine invertebrate: the octocoral Paramuricea clavata.

The red gorgonian Paramuricea clavata is a long-lived, slow-growing sessile invertebrate of ecological and conservation importance in the northwestern Mediterranean Sea. We develop a series of size-based matrix models for two Paramuricea clavata populations. These models were used to estimate basic life history traits for this species and to evaluate the viability of the red gorgonian populations we studied. As for many other slow-growing species, sensitivity and elasticity analysis demonstrate that gorgonian population growth is far more sensitive to changes in survival rates than to growth, shrinkage, or reproductive rates. The slow growth and low mortality of red gorgonians results in low damping ratios, indicating slow convergence to stable size structures (at least 50 years). The stable distributions predicted by the model did not differ from the observed ones. However, our simulations point out the fragility of this species, showing both populations in decline and high risk of extinction over moderate time horizons. These declines appear to be related to a recent increase in anthropogenic disturbances. Relative to their life span, the values of recruitment elasticity for Paramuricea clavata are lower than those reported for other marine organisms but are similar to those reported for some long-lived plants. These values and the delayed age of sexual maturity, in combination with the longevity of the species, show a clear fecundity/mortality trade-off. Full demographic studies of sessile marine species are quite scarce but can provide insight into population dynamics and life history patterns for these difficult and under-studied species. While our work shows clear results for the red gorgonian, the variability in some of our estimates suggest that future work should include data collection over longer temporal and spatial scales to better understand the long-term effects of natural and anthropogenic disturbances on red gorgonian populations.

[1]  E. Ballesteros,et al.  Mediterranean coralligenous assemblages: A synthesis of present knowledge , 2006 .

[2]  M. Nakaoka.  Yearly variation in recruitment and its effect on population dynamics inYoldia notabilis (Mollusca: Bivalvia), analyzed using projection matrix model , 1993, Researches on Population Ecology.

[3]  R. Coma,et al.  Immediate and delayed effects of a mass mortality event on gorgonian population dynamics and benthic community structure in the NW Mediterranean Sea , 2005 .

[4]  B. Kendall,et al.  Correctly Estimating How Environmental Stochasticity Influences Fitness and Population Growth , 2005, The American Naturalist.

[5]  L. Gerber,et al.  The use of demographic sensitivity analysis in marine species conservation planning , 2004 .

[6]  Mikel Zabala,et al.  LONG‐TERM ASSESSMENT OF TEMPERATE OCTOCORAL MORTALITY PATTERNS, PROTECTED VS. UNPROTECTED AREAS , 2004 .

[7]  D. Doak,et al.  Seedling establishment and life history trade-offs in alpine plants. , 2004, American journal of botany.

[8]  J. Silvertown,et al.  A COMPARATIVE DEMOGRAPHY OF PLANTS BASED UPON ELASTICITIES OF VITAL RATES , 2004 .

[9]  H. Lasker.  Population growth of a gorgonian coral: equilibrium and non-equilibrium sensitivity to changes in life history variables , 1991, Oecologia.

[10]  D. Doak,et al.  Book Review: Quantitative Conservation biology: Theory and Practice of Population Viability analysis , 2004, Landscape Ecology.

[11]  A. York,et al.  Using Age Structure to Detect Impacts on Threatened Populations: a Case Study with Steller Sea Lions , 2003 .

[12]  Paul Beier,et al.  Population viability analysis. , 2016 .

[13]  Rafel Coma,et al.  Seguiment temporal de la gorgònia vermella (Paramuricea clavata) de les Illes Medes. Exercici 2003 , 2003 .

[14]  Joaquim Garrabou,et al.  A 20‐year study on life‐history traits of a harvested long‐lived temperate coral in the NW Mediterranean: insights into conservation and management needs , 2002 .

[15]  M. Franco,et al.  Integrating vital rate variability into perturbation analysis: an evaluation for matrix population models of six plant species , 2001 .

[16]  H. Caswell.  Matrix population models : construction, analysis, and interpretation , 2001 .

[17]  Paul M. Thompson,et al.  Combining Power Analysis and Population Viability Analysis to Compare Traditional and Precautionary Approaches to Conservation of Coastal Cetaceans , 2000 .

[18]  J. Vacelet,et al.  Mortalité massive d'invertébrés marins : un événement sans précédent en Méditerranée nord-occidentale , 2000 .

[19]  T. Hughes,et al.  RECRUITMENT FAILURE, LIFE HISTORIES, AND LONG‐TERM DECLINE OF CARIBBEAN CORALS , 2000 .

[20]  P. Picco,et al.  A catastrophic mass‐mortality episode of gorgonians and other organisms in the Ligurian Sea (North‐western Mediterranean), summer 1999 , 2000 .

[21]  L. Crowder,et al.  LIFE HISTORIES AND ELASTICITY PATTERNS: PERTURBATION ANALYSIS FOR SPECIES WITH MINIMAL DEMOGRAPHIC DATA , 2000 .

[22]  M. Ribes,et al.  Growth in a modular colonial marine invertebrate , 1998 .

[23]  D. Doak,et al.  Life history of the long-lived gynodioecious cushion plant Silene acaulis (Caryophyllaceae), inferred from size-based population projection matrices. , 1998, American journal of botany.

[24]  J. Connell,et al.  A 30-year study of coral abundance, recruitment, and disturbance at several scales in space and time , 1997 .

[25]  D. Zanzi,et al.  Damage by fishing activities to the Gorgonian coralParamuricea clavata in the Ligurian Sea , 1997 .

[26]  M. Nakaoka.  Demography of the marine bivalve Yoldia notabilis in fluctuating environments: an analysis using a stochastic matrix model , 1997 .

[27]  J. Silvertown,et al.  Life history variation in plants: an exploration of the fast-slow continuum hypothesis , 1996 .

[28]  Eric S. Menges,et al.  Interpretation of elasticity matrices as an aid to the management of plant populations for conservation , 1996 .

[29]  C. Pfister,et al.  Harvesting Red Sea Urchins: Recent Effects and Future Predictions , 1996 .

[30]  P. Yoshioka.  Variable recruitment and its effects on the population and community structure of shallow-water gorgonians , 1996 .

[31]  Terry P. Hughes,et al.  RECRUITMENT AND THE LOCAL DYNAMICS OF OPEN MARINE POPULATIONS , 1996 .

[32]  M. Ribes,et al.  Reproduction and cycle of gonadal development in the Mediterranean gorgonian Paramuricea clavata , 1995 .

[33]  R. Coma,et al.  Sexual reproductive effort in the Mediterranean gorgonian Paramuricea ciavata , 1995 .

[34]  E. Pola,et al.  Seguiment temporal de la gorgònia Paramuricea Clavata de les Illes Medes. Exercici 2000 , 1995 .

[35]  P. Yoshioka.  Size-specific life history pattern of a shallow-water gorgonian , 1994 .

[36]  Larry B. Crowder,et al.  Predicting the impact of Turtle Excluder Devices on loggerhead sea turtle populations , 1994 .

[37]  J. Lawton,et al.  Organisms as ecosystem engineers , 1994 .

[38]  Miguel Franco,et al.  comparative plant demography - relative importance of life-cycle components to the finite rate of increase in woody and herbaceous perennials , 1993 .

[39]  Stephen P. Ellner,et al.  Simple Methods for Calculating Age‐Based Life History Parameters for Stage‐Structured Populations , 1992 .

[40]  S. Stearns,et al.  The Evolution of Life Histories , 1992 .

[41]  C. McFadden.  A Comparative Demographic Analysis of Clonal Reproduction in a Temperate Soft Coral , 1991 .

[42]  N. Gotelli.  Demographic Models for Leptogorgia Virgulata, A Shallow‐Water Gorgonian , 1991 .

[43]  R. Babcock.  COMPARATIVE DEMOGRAPHY OF THREE SPECIES OF SCLERACTINIAN CORALS USING AGE- AND SIZE-DEPENDENT CLASSIFICATIONS' , 1991 .

[44]  H. Lasker.  Clonal Propagation and Population Dynamics of a Gorgonian Coral , 1990 .

[45]  Shripad Tuljapurkar,et al.  Population Dynamics in Variable Environments , 1990 .

[46]  T. Hughes,et al.  Recruitment Limitation, Mortality, and Population Regulation in Open Systems: A Case Study , 1990 .

[47]  T. Done.  Simulation of recovery of pre-disturbance size structure in populations of Porites spp. damaged by the crown of thorns starfish Acanthaster planci , 1988 .

[48]  Hugh M. Caffey,et al.  SPATIAL AND TEMPORAL VARIATION IN SETTLEMENT AND RECRUITMENT OF INTERTIDAL BARNACLES , 1985 .

[49]  T. Hughes,et al.  Population Dynamics and Life Histories of Foliaceous Corals , 1985 .

[50]  R. Cook.  Growth and development in clonal plant populations , 1985 .

[51]  T. Hughes,et al.  Population Dynamics Based on Individual Size Rather than Age: A General Model with a Reef Coral Example , 1984, The American Naturalist.

[52]  M. True.  Etude quantitative de quatre peuplements sciaphiles sur substrat rocheux dans la region marseillaise , 1970 .