Jéssica Fenker is a PhD candidate at Australia National University. She is a herpetologist with a particular interest in adaptive radiations, species diversification, and savanna ecosystems. Jéssica shares her recent work, a multidisciplinary study, on characterising the biodiversity of lizards in the Cerrado, South America.
Jéssica Feneker posing with a goanna in Australia (left), and a false coral snake (Oxyrhopus trigeminus) during her fieldwork expedition in the Cerrado (right).
Personal link. Twitter | Website
Institution. Australian National University (ANU)
Academic life stage. PhD (finishing up)
Research themes and interests. Adaptation and
diversification of lizards (and sometimes snakes and amphisbaenians),
particularly savanna ecosystems, combining morphological, ecological and
genomic data across different geographic scales (from local communities to
intercontinental studies).
Current study system. Currently, I’m concluding my PhD
comparing patterns and processes of savanna reptile diversity across two
biogeographic realms – the Cerrado biome from South America and the Australian
Monsoonal Tropics of Australia. Cerrado is the most continuous and most diverse
savanna in South America, considered the second largest biome in the continent.
The also vast Australian Monsoonal Tropics has low population density and is
considered the most well conserved savanna in the world. Comparing these two
similar but evolutionarily independent systems, I expected to identify common
processes underpinning the high diversity of tropical savanna systems on
convergence and disparity in morphological traits, but also looking for region
specific spatial patterns of species richness, phylogeographic diversity and
endemism. I am also interested in how dispersal limitation, environment and
geographic barriers at the landscape scale can predict differences in
phylogeographic structure across co-distributed taxa.
Recent paper in Journal of Biogeography. Fenker J, Domingos
FMCB, Tedeschi LG, et al. (2020) Evolutionary history of Neotropical savannas
geographically concentrates species, phylogenetic and functional diversity of
lizards. Journal of Biogeography. 47(5): 1130–1142. https://doi.org/10.1111/jbi.13800
(left) The lizard, Norops (Anolis) meridionalis, one of the species featured in our analysis and present across Cerrado’s distribution (Photo: Jessica Fenker). (right) The lizard, Polychrus acutirostris, one of the species featured in our analysis and present across Cerrado’s distribution (Photo: Jessica Fenker).
Motivation for recent paper. Our motivation for this study was to map spatial patterns of diversity and endemism using an integrative approach, to highlight key areas for the past and future maintenance of biodiversity in the Cerrado. Previous studies have focused on a single metric (species composition), neglecting the fact that “species” within are often composed of multiple cryptic taxa that can co-occur and might be associated with different habitats. The Cerrado is a continent-size biome, with a complex landscape of alternating ancient plateaus and younger inter-plateau depressions. Still, studies debate its origin and process that affect the spatial distribution of species diversity, making our study pertinent for the region. The Cerrado is also a highly threatened savanna ecosystem, so understanding processes that shape diversity will help provide management tools and priorities for conservation.
A series of vistas from the Cerrado (Photos: Jéssica Fenker)
Key methodologies. In order to identify biodiversity
hotspots more robustly while integrating multiple factors, we used a
multi-dimensional approach, combining taxonomic, phylogenetic and functional
data to identify unique areas of richness and endemism within Cerrado. We
generated species distribution models using distribution records for all
Cerrado lizard species. These, combined with mitochondrial DNA phylogenies and
natural history data allowed us to map species richness, phylogenetic and
functional diversity, and phylogenetic and weighted endemism. Phylogenetic
endemism maps were then cross-referenced against protected areas to calculate the
amount of evolutionary history preserved within these areas. For me, the most
interesting aspect of this paper was the co-opting of previously published
phylogeographic studies to help refine species limits and prioritise regions
for conservation in Cerrado.
Major challenges. The biggest challenge was to gather and
synthethise all the relevant available information, especially with the
different genes, and the challenges of deciding how to delimit species. The
availability of sequencing data for Brazilian species has grown, although
characterising genetic variation within and among different taxa is still not a
common component of much biodiversity research. Nonetheless, we need more
genetic sequencing to improve diversity estimates, as many reptile groups are
known to actually belong to species complexes, and there is a need to surpass
the inadequate taxonomy.
Major results. We highlighted both climatically stable
plateau regions and environmentally heterogenous (less stable) valley areas as
hotspots of evolutionary diversity, being higher in taxonomic, phylogenetic,
and functional diversity. The central region of the Cerrado, a vast and
climatically stable plateau, stands out as important under all biodiversity
metrics. With the inclusion of evolutionary relationships in biodiversity
assessment, we detected four regional hotspots with high concentration of
spatially restricted evolutionary diversity. Protected areas cover only 10% of
the Cerrado area and hold only 11.64% of the summed phylogenetic endemism of
all lizards in the biome.
Hotspot areas for conservation based on their high levels of phylogenetic endemism (PE). Heat colours represent priority areas.
Next steps. Creating new protected areas based on our identified regional hotspots will be important for future conservation. Ideally, this will combine sustainable land use and management with cultural and economic benefits to local communities. The challenge is to overcome Brazilian conservation policies, that often neglect non-forest ecosystems, and to conciliate conservation with human goals, as Cerrado has been dramatically converted to soy monoculture and cattle raising.
If you could study any organism on Earth, what would it be and why? I would definitely continue with squamate reptiles–they are not only the coolest organisms on Earth, but they are also excellent models to study biogeography, ecology and evolution. First, they use they habitat in a huge variety of ways, with different species being fossorial, terrestrial, aquatic and arboreal (and anything in between!). Second, as ectotherms they are particularly sensitive to climate variation in space and time. Finally, lizards in particular are relatively easy to sample in the wild, with high diversity and comparatively well-established knowledge of species’ distributions. I also love to do fieldwork, during day or night, and spot these amazing creatures.
Anything else you’d like the share? I’m a Brazilian student and have had the opportunity to develop my PhD in one of the best Australian universities with a supportive advisor (Professor Craig Moritz), and I consider myself really lucky to have this opportunity. Starting in June, I will join Professor Lacey Knowles’ laboratory at the University of Michigan, United States, as a post-doc working on conceptual issues related to the species delimitation process – an issue that was pertinent in all my PhD chapters. As a female and first-generation PhD candidate, I am involved in projects that promote equal gender opportunities in science, especially in South America where culturally ingrained masculine pride is normalised, and I aim to continue participating in projects that benefit Brazilian biodiversity.