Since 1986 I have been active in research on diverse topics ranging from island ecosystems, taxonomy (of plants, snails, insects, spiders, lizards, frogs and mammals), phylogenetics, ecology, anatomy, and morphological evolution. This can all be summarised as an interest in discovering new species, studying how they evolve and saving them from extinction.

  • Species discovery - species discovery can be done by studying a particular group of organisms, or a specific geographical area.I have focussed on specific groups in the Seychelles islands, Madagascar and French Polynesia (new species listed here) and have carried out comprehensive biodiversity assessment of the non-marine life of all 115 Seychelles islands, providing current data on the distribution and status of all species. This simple inventory approach provides useful information but only as an isolated picture. I also developed in-depth ecological investigations on several islands of the Seychelles group. The main focus was on Silhouette island which retains the most diverse natural habitats of any island in the region. This approach may be expanded into areas of Madagascar and New Guinea.This all combines into an interest in the evolution of island ecosystems.

  • Evolutionary history - the ecological and conservation significance of basic taxonomy work is indicated by my work on Indian Ocean giant tortoises. The development of the giant tortoise conservation project enabled me to pursue research into the morphological, behavioural and dietary adaptations of these species and to start investigating their role in island ecosystems. This has led to an interest in tortoise and turtle evolution, and an unexpected investigation into hunting behaviour shown by some giant tortoises.

  • Partula snails - taxonomy, evolution and conservation of the historically important snail family and their infamous predators Euglandina rosea snails and Platydemus flatworms

  • Plant health and island ecology - what the extinction of snails means for plants.The extinction of most Pacific-island tree snails has meant that forests on these islands now lack major consumers of algae, fungi and diseased plant tissue. I am investigating whether the extinction of the snails has been followed by a build-up of leaf covering organisms and more plant diseases.This has implications for the stability of island ecosystems but also connects to ongoing efforts to reintroduce the snails back into these forests.


    Much of my research work has linked to conservation of island species and ecosystems. My conservation activity has covered active habitat and species management, reintroduction, conservation breeding, population monitoring and mathematical modeling. Published models include the effects of demographic instability on extinction risks of small populations, evolutionary adaptation to island conditions and the relevance of the metapopulation to the processes of colonisation and the dynamics of invasion by alien snails.

  • Partula snails - ecology of the snails and their predators population and climate modeling

  • Seychelles islands - invasion biology, development and politics. Significant project included saving the Seychelles sheath-tailed bat, the world's most threatened bat, and giant tortoises. This work integrated evolutionary ecology and conservation and demonstrated that many received conservation problems can be accommodated by a healthy ecosystem. This also indicated that the conventional orthodoxy that island systems are especially prone to disruption by invasive alien species may be overly simplistic.

  • Invertebrates and the Red List - evaluating the status of the world's invertebrates

  • Climate change - ecosystem change, adaptability, frogs, snails and others

    Partula snails

    Biodiversity assessment

    Biology teaching

  • Contact

    Justin Gerlach by e-mail