Jacqueline Mattos is a PhD candidate at the University of Campinas – UNICAMP. She is a genome scientist and bioinformatician with special focus on the evolutionary and adaptive processes of natural plant populations. Here, Jacqueline shares her recent work on the climate and biotic drivers of range limits in a neotropical orchid.
Institute. UNICAMP (University of Campinas – Brazil).
Academic life stage. PhD Candidate.
Major research themes. Evolutionary ecology; evolutionary genomics; neotropical plants; conservation biology.
Current study system. Our current species of interest is the neotropical orchid Epidendrum fulgens – a terrestrial perennial found mostly on sand dune vegetation, in the south and southeastern coastal areas of Brazil. It belongs to the subgenus Amphyglottium, a group of species with ecological preferences for harsh environments. This species is a cool study system because it has a wide geographical distribution and interesting ecological preferences, being able to grow in both sand dunes and rocky outcrops in different locations of its range.
Recent JBI paper. De Mattos, J. S., Pinheiro, F., Luize, B. G., Chaves, C. J. N., de Lima, T. M., Palma da Silva, C., & Leal, B. S. S. (2023). The relative role of climate and biotic interactions in shaping the range limits of a neotropical orchid. Journal of Biogeography, 50(7): 1315–1328. https://doi.org/10.1111/jbi.14629
Motivation behind this paper. Despite we had already studied the genetic diversity and population genetic structure of E. fulgens across its geographical range, we never addressed any biogeographical hypothesis. In this paper, we evaluated the centre-periphery hypothesis (CPH), a major biogeographic paradigm, using the highly narrow and linear distribution of E. fulgens as a system to understand the different factors (biotic and abiotic) underlying species persistence in geographical extremes/margins. Thus, our main motivation was to understand the patterns generated by the CPH in E. fulgens, while improving our understanding of the biogeography of the species.
Left: Epidendrum fulgens population in southeastern Brazil (Florianópolis, Santa Catarina state). Right: Sand dunes with restinga vegetation, the main kind of habitat for E. fulgens, at Florianópolis site.
Key methodologies. Our work was based on three main methodological components: geographical distribution, ecological niche modelling and genetic diversity patterns. Basically, we integrated empirical data on geographical distribution, pollinator richness and genetic diversity along the entire range of the species. We performed niche models to predict niche limits, and polynomial and linear regression models to investigate the associations between ecological niche and species range, as well as to test the relationship between genetic-derived metrics and geographical and ecological distances. Especially, what provided the newest insights was the addition of pollinator richness into one of our niche models.
Unexpected challenges. Our main challenge was to integrate the great amount of data that we wanted to include in the study. Another challenge was to differentiate the geographical component from the ecological/niche component. Adding the biotic interactions component was definitely an important decision, considering that many papers on CPH still do not account for the biotic processes affecting species ranges.
Major results. We found that ecological conditions become more marginal towards the edges of E. fulgens range, and that both low-latitude and high-latitude margins have different patterns and shape the species distribution differently. We also found that genetic diversity is mostly decreasing, while genetic differentiation is mostly increasing towards both margins. Our study corroborated the CPH regarding ecological and genetic patterns of variation in space, and highlighted distinct factors limiting geographical distribution at the opposite margins of E. fulgens’ range. Our work helps understanding the roles of both biotic and abiotic factors affecting plant distribution ranges in a latitudinal gradient. This could potentially aid in conservation practices in vulnerable and disturbed ecosystems.
The yellow flowers (left) are only one of the morphotypes for E. fulgens, that can be also orange and red (right), in the different locations of its range.
Next steps for this research. I am currently working on the generation of the first chromosome-scale genome assembly for E. fulgens, which will also be the first one for the whole Epidendrum genus. We are also using RNA-seq data to understand the main evolutionary mechanisms (natural selection; genetic drift) that are happening in range margins. This is all part of my doctorate thesis.
If you could study any organism on Earth, what would it be? To me, fungi are exceptionally interesting! I would love to study fungi alongside with plants in the next stages of my academic career.