Oral Presentation Australian Society for Fish Biology Conference 2017

Multi-scale environmental processes influence juvenile recruitment success in a non-migratory fish (#42)

Mischa Turschwell 1 , Ben Stewart-Koster 1 , Stephen Balcombe 1 , Fran Sheldon 1 , Erin Peterson 2
  1. Australian Rivers Institute, Griffith University, Nathan, QLD, Australia
  2. Australian Centre for Mathematical and Statistical Frontiers and the Institute for Future Environments, Queensland University of Technology, Brisbane , Queensland , Australia

The distribution and population structure of organisms is governed by a broad suite of biotic and abiotic variables, interacting across multiple spatial and temporal scales. Recruitment is a key spatially and temporally variable demographic process critical to the maintenance of successful populations. Isolating and quantifying the multi-scale environmental drivers of recruitment has proven to be difficult, especially in freshwater fishes. We built a Bayesian hierarchical model to quantify the relationship between juvenile northern river blackfish recruitment success, and environmental predictors across two spatial scales. We found a 0.995 probability that increased broad-scale stream temperature negatively affected juvenile recruitment success. We also found that there was a 0.968 probability that the fine-scale relationship between recruitment and riparian foliage cover was dependent on temperature. This suggests that broad-scale thermal conditions provide the template upon which at least one local environmental variable influences recruitment success. Isolating the drivers of key population processes and understanding the spatial and temporal scales at which they operate is critical to gain insight into likely changes in population persistence, along with the potential future impacts of habitat degradation and climate warming on freshwater fishes.