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Reef Sites (reef + site)
Selected AbstractsStability in temperate reef communities over a decadal time scale despite concurrent ocean warmingGLOBAL CHANGE BIOLOGY, Issue 1 2010RICK D. STUART-SMITH Abstract Despite increasing scientific and public concerns on the potential impacts of global ocean warming on marine biodiversity, very few empirical data on community-level responses to rising water temperatures are available other than for coral reefs. This study describes changes in temperate subtidal reef communities over decadal and regional scales in a location that has undergone considerable warming in recent decades and is forecast to be a ,hotspot' for future warming. Plant and animal communities at 136 rocky reef sites around Tasmania (south-east Australia) were censused between 1992 and 1995, and again in 2006 and 2007. Despite evidence of major ecological changes before the period of study, reef communities appeared to remain relatively stable over the past decade. Multivariate analyses and univariate metrics of biotic communities revealed few changes with time, although some species-level responses could be interpreted as symptomatic of ocean warming. These included fishes detected in Tasmania only in recent surveys and several species with warmer water affinities that appeared to extend their distributions further south. The most statistically significant changes observed in species abundances, however, were not related to their biogeographical affinities. The majority of species with changing abundance possessed lower to mid-range abundances rather than being common, raising questions for biodiversity monitoring and management. We suggest that our study encompassed a relatively stable period following more abrupt change, and that community responses to ocean warming may follow nonlinear, step-like trajectories. [source] Temporal variability in fish larval supply to Malindi Marine Park, coastal KenyaAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2009Boaz Kaunda-Arara Abstract 1.Larval supply to reef sites influences adult population structure, reef connectivity and conservation potential of marine reserves, but few studies have examined this topic in the Western Indian Ocean (WIO). 2.Fish larval supply to Malindi Marine Park in Kenya was studied using light-traps for a period extending from March 2005 to June 2006. The traps caught pre-settlement fish larvae at two sites spread across the park. Catch rates (number trap,1night,1) were used to represent larval abundance and to test the influence of seasonality and habitat characteristics on larval abundance in the park. 3.Thirty-three species of reef fish larvae in 15 families were sampled. Larval supply to the park was more diverse during the north-east monsoon season (30 species) than in the south-east monsoon season (15 species), with inter-annual variability in abundance. Higher catch rates of larvae occurred in the north-east monsoon month of March in both 2005 and 2006 and the inter-monsoon month of September 2005. 4.Family-specific temporal variation in larval abundance showed dominance of the families Apogonidae and Caesionidae in the park, with higher abundance during the north-east monsoon months. A few families (e.g. Canthigasteridae) showed dominance during the south-east monsoon season. Regression and rank Spearman correlation analyses indicated positive correlation of chlorophyll-a with larval supply while water depth had significant negative correlation with abundance of the Apogonidae and Caesionidae. 5.On a short-term temporal scale larval abundance in the park was highly correlated with the new moon lunar phase more than the full moon. However, on a long-term scale (16 months) larval supply to the park was significant only over a 2-month period and was correlated with environmental productivity more than ambient temperature. These results are useful in understanding the role of larval supply in structuring adult fish populations and the factors that force larval flux at reef sites. Copyright © 2009 John Wiley & Sons, Ltd. [source] Relationship of habitat stability and intra-specific population dynamics of an obligate corallivore butterflyfishAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue S1 2005Michael P. Crosby Abstract 1.Intra-specific behavioural manifestations, as measured by territory size and conspecific agonistic encounters, population size and recruitment of the obligate corallivore butterflyfish Chaetodon multicinctus (Family: Chaetodontidae) were examined over a 5-year period at three Hawaiian coral reef sites, each receiving different levels of non-point-source terrigenous sediment runoff. 2.All three sites indicated significant correlations for percentage coral cover with territory size, fish size, and number of adult C. multicinctus, and for agonistic encounters with number of juvenile C. multicinctus. However, the site most impacted by sediment runoff indicated no significant correlations for percentage coral cover with territory size, fish length, number of adult C. multicinctus, number of agonistic encounters, or C. multicinctus juveniles; nor for number of agonistic encounters with number of juveniles. 3.The site moderately to minimally impacted by sediment runoff exhibited significant correlations for percentage coral cover with number of adults, while the site with no sedimentation impacts exhibited significant correlations for percentage coral cover with fish size, number of adults and number of juveniles. 4.Significant differences were found to exist between all three sites for agonistic encounters, territory size, fish size, number of C. multicinctus juveniles and percentage coral cover. The most highly impacted site exhibited a significantly higher number of adult C. multicinctus that were significantly smaller in size than either the minimally impacted and non-impacted sites. 5.The study design purposely selected high coral cover habitats (means ranged from 81.4% to 96.5%) at each site. Within this limited range of relatively high coral cover habitat, relative habitat stability resulting from a range of historic sediment inputs between sites appears to be the stronger forcing function for observed intra-specific behavioural manifestations, population size and recruitment than percentage coral cover. 6.Study results indicate that obligate corallivore butterflyfish behavioural manifestations, population size and recruitment may be used as a benchmark for changes in habitat stability for coral reef communities, and support the general premise of the butterflyfish indicator species hypothesis. Copyright © 2005 John Wiley & Sons, Ltd. [source] Applying forest restoration principles to coral reef rehabilitationAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 5 2003N. Epstein Abstract 1.Forest restoration through silviculture (gardening) programs revives productivity, biodiversity, and stability. As in silviculture approaches, the coral ,gardening' strategy is based on a two-step protocol. 2.The first step deals with the establishment of in situ and/or ex situ coral nurseries in which corals are farmed (originating from two types of source material: asexual [ramets, nubbins], and sexual [planula larvae, spat] recruits). 3.The second is the reef rehabilitation step, where maricultured colonies are transplanted into degraded sites. 4.We compare here the rationale of forest restoration to coral reef ecosystem restoration by evaluating major key criteria. As in silviculture programs, a sustainable mariculture operation that focuses on the prime structural component of the reef (,gardening' with corals) may promote the persistence of threatened coral populations, as well as that of other reef taxa, thus maintaining genetic diversity. In chronically degrading reef sites this may facilitate a halt in biodiversity depletion. 5.Within the current theoretical framework of ecosystem restoration, the recovery of biodiversity indices is considered a core element since a rich species diversity provides higher ecosystem resilience to disturbances. 6.The gardening measure may also be implemented worldwide, eliminating the need to extract existing colonies for transplantation operations. At degraded reef sites, the coral gardening strategy can assist in managing human and non-human stakeholders' requirements as is done in forest management. Copyright © 2003 John Wiley & Sons, Ltd. [source] | ||||||||||