Supply side ecology

The majority of marine benthic invertebrates exhibit a complex life cycle, that includes separate planktonic and bottom dwelling phases, linked by a settlement event. The analysis of mechanisms which control settlement and recruitment in marine organisms and determination of the conditions under which recruitment variation affects adult distribution and abundance is fundamental to advancing our understanding of population and community variability and hence our ability to manage natural systems.  My research uses intertidal barnacles as convenient model organisms to address these questions. 

Role of larval supply in dictating adult distribution 

Supply of planktonic larvae to the adult habitat may dictate adult abundance or distribution.  Work on the Isle of Man showed that biotic interactions at settlement (Jenkins et al 1999) not larval supply (Jenkins and Hawkins 2003) were responsible for dictating adult distribution of Semibalanus balanoidesover the wave exposure gradient of the shore. 

More recently I have examined the relative roles of larval supply, settlement behaviour and post settlement mortality to explain the differential distribution of two barnacles Chthamalus stellatusand C. montaguiover the wave exposure gradient.  Planktonic larval sampling has shown that while larval production mirrors the distribution of adults, larval supply of cyprids competent to settle does not.  Instead adult distribution appears to be set at settlement due to the behaviour of larvae (Jenkins 2005). 

 Consequences of recruitment variation to adult population dynamics

The role of variation in levels of supply, settlement and recruitment to the adult habitat in dictating the dynamics of benthic invertebrate populations and wider effects at the community level have been debated for many years.  My work has examined how strong density dependent mortality as a result of competition for limiting resources , can strongly modify patterns established at settlement.  Results of work on Semibalanus balanoides (shown left) show that settlement density can have positive, neutral and negative effects on adult density owing to processes operating soon after settlement (Jenkins et al 2008).





Incorporating larval/ juvenile traits into recruitment modeling

In recent years the importance of larval and juvenile traits has been recognised in determining post-settlement success.  Through collaborations with Dr Luis Gimenez of Bangor University and Dr Michael Burrows of the Scottish Association for Marine Science I am exploring how we can integrate traits of larvae and of juveniles to better predict consequences of settlement variation to teh dyanmics of adult populations.  This work is currently supported by a Standard NERC grant .   

Work supported by:

NERC New Investigators Award (NER/M/S/2002/00117) (Jenkins) £50,868 Interaction of recruitment and post-recruitment processes in controlling population dynamics of benthic marine invertebrates (February 2003- March 2005)

NERC Standard Grant NEH006702/1  £489,629  Jenkins SR, Gimenez L, Burrows MT  Towards an integrative theory of recruitment in marine benthic organisms January 2010