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Biodiversity and ecosystem functioning in rockpools WHY ROCKPOOLS? •Accessible •Mesocosm features when emersed •Open to the marine environment when immersed •Diverse array of primary producers and consumers •A range of emergent ecosystem properties can be measured Primary production Balance between community respiration and production Nutrient uptake WHY NOT ROCKPOOLS? •Variability in size, shape, complexity •Availability : •Natural? •Artificial? Biodiversity-ecosystem functioning Rockpools as model experimental systems: 1) Susceptibility of marine algal communities to alien invasion: the role of functional diversity 2) Top down and bottom up control of rockpool algal communiuties:the importance of species identity in ecosystem functioning 3) Biodiversity and ecosystem functioning: tests using rockpools as natural mesocosms 1) Susceptibility of marine algal communities to alien invasion: the role of functional diversity PICTURE Sargassum muticum NERC Small Grant (NER/B/S/2003/00266) 2) Top down and bottom up control of rockpool algal communiuties:the importance of species identity in ecosystem functioning • Top down- dominant grazer Patellid limpets • Bottom up - nutrient supply Factorial experiment Treatment 1 2 3 4 Grazer + + - Nutrient + + - Ephemeral algal cover 100 % cover - Nutrients + Nutrients Two way ANOVA Grazers P < 0.05 Nutrients P < 0.001 50 0 + Grazers - Grazers Net primary production mg O2 l-1 min-1 0.25 0.20 - Nutrients + Nutrients 0.15 ? 0.10 0.05 0 + Grazers - Grazers Two way ANOVA Grazers x Nutrients P < 0.001 Species identity dictates ‘ecosystem functioning’ Variety of ephemeral species respond to experimental perturbations Highly productive green algae mg O2 l-1 min-1 0.25 0.20 - Nutrients + Nutrients 0.15 ? 0.10 Red algae Ceramium spp. 0.05 0 + Grazers - Grazers of low productivity Ephemeral algal cover 100 % cover - Nutrients + Nutrients Two way ANOVA Grazers P < 0.05 Nutrients P < 0.001 50 0 + Grazers - Grazers Net primary production mg O2 l-1 min-1 0.25 0.20 - Nutrients + Nutrients 0.15 Two way ANOVA Grazers x Nutrients P < 0.001 0.10 0.05 0 + Grazers - Grazers 3) Biodiversity and ecosystem functioning: tests using rockpools as natural mesocosms Observational correlative approach Models relating physical and biological variables to key ecosystem properties Manipulative experimental approach NERC Standard Grant (NE/B504649/1) (Jenkins, Thompson, Hawkins, Burrows) Key questions: •Develop statistical models linking physical and biological attributes to ecosystem functions. •To determine the relative importance of functional versus species diversity in controlling ecosystem function and assess the specific role of identity. •To determine how consumer diversity affects primary producer diversity and biomass and establish the consequences for ecosystem functioning. •To determine changes in ecosystem function occurring as a consequence of natural succession •To use a modelling approach to link observations made in natural systems and experiments, to provide a predictive understanding of biodiversity loss in the marine environment.