The Ecological and Evolutionary consequences of tropicalisation

Project Rationale:

Climate warming is creating novel ecological communities whereby species compositions and interactions differ from a historical baseline. Notably, tropical marine species are being documented in temperate biogeographic regions, while the ranges of temperate species are shifting poleward. This phenomenon is known as ‘tropicalisation’; yet very little is known of its ecological and evolutionary consequences. For instance, we do not know if temperate prey species are able to defend themselves against tropical marine predators nor how the influx of tropical predators affects community composition (“top-down” effects). Tropicalisation may also have genetic/evolutionary consequences. For example, range contracting temperate species may experience an overall loss of genetic diversity and disappearance of unique genetic clades - which in turn may have consequences on the capacity for species to adapt to climate warming and future evolutionary trajectories (i.e. extinction risk). This PhD will draw from a wide variety of disciplines and theory, ranging from predator induced defenses/predator-prey interactions/community ecology to molecular phylogeography and phylogenetics to address key knowledge gaps on the ecological and evolutionary consequences of tropicalisation. The project will focus on a transition zone between tropical and temperate biogeographic regions where tropicalisation has been preliminarily documented but its consequences have not been established.

Methodology:

Field surveys of species occurrence and diversity will be paired with historic collections from natural history museums and literature surveys to firmly establish the geographic extent of tropicalisation across the transition zone between tropical and temperate biogeographic regions. These results will be paired with a survey of the palaeontological literature and museum collections to compare modern species range change and diversity with the deeper past (last interglacial, ~125Kya). Research will focus on rocky shore gastropods, but there is scope to include other marine invertebrate taxa as well. Field experiments will be set up across the transition region to assess the influence of tropical predators upon temperate prey and communities (e.g. phenotypic and behavioural adaptations, and changes in community composition). The student will assess the evolutionary consequences of range contraction of temperate species using phylogeographic and population genetic methods. For example, the student will assess if range contraction of temperate species is leading to a significant reduction in genetic diversity and unique genetic clades. This project will be conducted in collaboration with international scientists and collection permits will be obtained under the guidelines of the international countries where the field research will be conducted.

Training:

The INSPIRE DTP programme provides comprehensive personal and professional development training alongside extensive opportunities for students to expand their multi-disciplinary outlook through interactions with a wide network of academic, research and industrial/policy partners. The student will be registered at the University of Southampton and hosted at both the University of Southampton (National Oceanography Centre) and the Natural History. Specific training will include: courses in molecular phylogenetics/phylogeography, statistics, biogeographical modelling, scientific writing, and public speaking/presentation. There will also be opportunities to develop teaching through guest lectures and demonstration on field and lecture-based modules. Travel to international scientific meetings to present project results will also be encouraged.