Julian G. de Aledo is a PhD candidate at the Universidad Autónoma de Madrid, Spain. She is a ecologist with special focus on biodiversity of tropical plants. Here, Julia shares her recent work on plant diversity and distribution in the western Amazonia.
PhD candidate Julia G. de Aledo
Institute. Universidad Autónoma de Madrid and Universidad Rey Juan Carlos, Spain
Academic life stage. PhD candidate
Major research themes. My major research interests revolve around plant diversity, distribution, and uses in western Amazonia, particularly focusing on how plants and people interact in tropical ecosystems across gradients.
Current study system. I am currently studying the woody plants of western Amazonia, which include approximately 110 different families with distinct growth forms, from large trees, to palms, ferns, small bushes, lianas and hemiepiphytes. Despite an estimated 50,000 plant species in the Amazon basin, only 14,000 tree species have been described, which highlights the vast amount of work still to be done.
Recent JBI paper. de Aledo, J. G., Paneghel, M., Cayuela, L., Matas-Granados, L., Ben Saadi, C., Salinas, N., La Torre-Cuadros, M. d. l. Á., García-Villacorta, R., & Macía, M. J. (2023). Floristic diversity, composition and dominance across Amazonian forest types respond differently to latitude. Journal of Biogeography, 50, 673–698. https://doi.org/10.1111/jbi.14561
Motivation behind this paper. During fieldwork, we have observed distinct variations in species diversity and composition across different forest types. We noticed that floodplain forests appeared to have a lower diversity of species compared to the well-drained forests yet filled with species with different physiological adaptations to the seasonal flood pulse. On the other hand, in submontane forests, diversity seemed to peak at higher elevations (500 m). These observations led us to question whether there was a discernible pattern in how plant species respond to latitude in each forest type to ultimately understand the causes of the vast diversity of the Amazonian ecosystem.
Drawing of the diversity of species and life forms in western Amazon.
Key methodologies. In the fieldwork, we gathered information from unexplored areas using 10 temporary plots per region located 300 meters apart. This approach allowed us to obtain maximum floristic variability within an area, which is crucial when studying diverse ecosystems. Moreover, all data were gathered by the authors themselves, and no data from existing databases were used.
In terms of the analysis, we made a plot called non-metric multidimensional scaling (NMDS) and used a smooth line to show how latitude affects the changes in species composition across plots . This helped us see if there was a trend or pattern in how each forest type responds to latitude. Additionally, we explored dominant species through their changes in abundance, which helped us understand how these species adapt and dominate over large areas. We used a novel stream graph approach to better illustrate these changes, providing new insights into their distribution and dispersion peaks.
Forest vertical structure of woody plants in Reserva Yanesha, Peru.
Unexpected challenges. In this type of field campaign, nothing can be predicted in advance. Nonetheless, we encountered some outcomes and challenges even beyond our imagination. For example, we ended up collecting more species than we had expected. This led to difficulties in transporting the collected material, as well as troubles in the final identification of some of the specimens, mostly the ones without fertile material. Another important challenge was reaching high trees (over 20 meters) for collection, which required specialized equipment and climbing expertise. Finally, the flooding of the rivers due to heavy rains made the fieldwork complicated, leaving us confined to the campsite for several days. Despite this, the team was able to ultimately export 5000 vouchers and identifying 1300 species for future research.
Major results. Our recent work confirms the latitudinal diversity gradient towards the equator both for alpha and beta diversity. This provides further evidence for the importance of tropical forests in maintaining global biodiversity. However, the finding that floodplain forests did not increase their diversity towards the equator as much as other forest types did, highlights the need for further research on these forests and their species performance. Despite this, the number of species found was still very high, with 100 species per 0.1 ha.
Concerning species dominance, this study also reveals different responses to latitude. Floodplain forests harbored more homogenous dominant species abundances, while well-drained forests had dominant species that peaked heterogeneously along the gradient, giving insights of differences in dispersion strategies.
An additional important contribution is that the field team have generated a comprehensive database of almost 30,000 individuals that is available for use by other researchers in the field of tropical community ecology of tropical forests (https://datadryad.org/stash/dataset/doi:10.5061/dryad.jm63xsjcc). Botanical vouchers obtained in this research were deposited in different herbariums in Ecuador (QCA, QCNE), Bolivia (LPB), Peru (USM, MOL) and Spain (MA).
Left: aerial image of Amazonian forest surrounding the Tambopata River in the Tambopata National Reserve (Madre de Dios, Peru). Right: photo of Coussapoa ovalifolia tree with aerial roots in Amazonian flooded forest.
Next steps for this research. Further investigation can be done to understand the underlying mechanisms driving the observed latitudinal diversity gradient in our study. This can involve exploring in depth floodplain forests to highlight its importance, promote their conservation and to understand its species adaptations. Also, including in situ mechanistic factors as temperature, precipitation, and soil nutrients in the analysis could improve the latitudinal model. Incorporating phylogenetic information can also provide insights into the evolutionary history of tropical plant communities and their responses to environmental change. By studying functional attributes of the species, we can understand the adaptation of species to seasonally harsh conditions. Finally, efforts can be made to expand this investigation to other regions and biomes to compare the latitudinal patterns observed in our study in other environments.
If you could study any organism on Earth, what would it be? Tropical woody plants are fascinating. In particular, I like lianas, which are a unique group of plants with unique growth form which allows them to climb up trees and compete for resources, affecting the structure and dynamics of the forest community. The Lecythidaceae family is also an interesting group to study because of their large flowers and fruits, which are important food sources for many animals and humans.
Drawing of Couratari guianensis (Lecythidaceae) fruit by Julia G. de Aledo
Anything else to add? In addition to my work on tropical woody plants, I also conduct research on ethnobotany, ecosystem services, and the cultural diversity of indigenous communities in tropical forests in western Amazonia. I believe that including people in ecology research is essential for understanding how species respond to changes in their environment, and for developing effective conservation and management strategies. Additionally, I am interested in using visual data analysis techniques, including bioinformatics, modelling, statistics, and data visualization, to better understand complex ecological systems.
Changes in the abundance of each dominant species by forest type in western Amazonia.