In our ‘Field Diaries’ series, The Applied Ecologist is sharing stories from a range of different fieldwork experiences. Mariana Silva Ferreira shares being involved in the largest long-term monitoring study on small mammals based in Brazil.
About the Author
Mariana Silva Ferreira, she/her
Affiliation:
- Associate Researcher, Universidade Federal do Rio de Janeiro (Federal University of Rio de Janeiro), Brazil
- Auxiliar Professor, Universidade Federal do Estado do Rio de Janeiro (Federal State University of Rio de Janeiro), Brazil
Ecology interests:
Population ecology, life histories, mammals
Overview of fieldwork
For over 10 years, I was part of the team at the Vertebrate Laboratory of the Federal University of Rio de Janeiro (UFRJ), which collected data on populations of small mammals (marsupials and rodents) in the Serra dos Órgãos National Park, a protected area of the Atlantic Forest located approximately two hours from the city of Rio de Janeiro, Brazil. This is the largest long-term, uninterrupted study of small mammal monitoring in tropical forests in South America, which began in 1997 and ended in 2019, completing 22 years. I began working on the project in 2006, the week after I started my undergraduate internship at the laboratory. It was my first fieldwork and I fell in love with it. Internships during undergraduate studies are a very interesting practice that we have adopted in Brazil. Students develop their own scientific research and many collect their own data, as I did. The work consisted of capturing the animals in live traps, tagging them with ear tags and obtaining bionomic measurements, such as weight, size and signs of reproductive activity. The animals were then released, and we returned the next day to do the same procedure. In total, there were five nights of fieldwork, every two months, six times a year. This routine was part of my undergraduate, master’s and doctoral studies.
But beyond the work, fieldwork brings us unique memories. My best friends are the people who spent hours in the forest capturing possums, getting wet in the rain or extreme heat, eating tuna paste sandwiches and bathing in waterfalls. We still laugh a lot about the stories and remember specific animals, such as the possum number TDI 2571/3306, which provided us with a lot of reproductive data (we captured this female with five litters over more than two years).
I recently read an article about the extinction of experience among ecologists. This worries me, because I learned a lot during my fieldwork. This includes everything from how to live with different people to how to organize fieldwork, from logistics to reporting to funding agencies, as well as observing the behaviour and peculiarities of each animal. If you have the opportunity, do fieldwork or seek out volunteer work. You won’t regret it.
Why is this an important project?
This long-term study is essential for understanding population dynamics in tropical forests. Despite the increase in knowledge about these unique ecosystems and species in recent decades, there are few long-term studies that allow us to assess population growth or decline, and the factors responsible for this variation. Our publications demonstrate that, even in one of the most biodiverse ecosystems on the planet, small mammal populations self-regulate, that is, among the multiple possible interactions, competition for a limiting resource is the most important.
In addition, the 22 years of study allowed more than a hundred people to participate directly or indirectly in the organization and collection of data, either by developing their theses and dissertations, or through volunteering. To date, 5 doctoral theses, 21 master’s dissertations and 39 undergraduate research projects have been conducted with this data.
We are currently seeking to understand the impacts of climate change on the ecosystem and these species. In this way, we can assess how changes in precipitation and temperature over two decades have affected the populations of small mammals. This information is crucial to foster conservation and management actions in this biodiversity hotspot.
Where can we find more information?
More information about this long-term study can be found at the links below:
- Special issue: Oecologia Australis: Garrafão: 22 Years of the Longest Small Mammal Monitoring Study in Brazil https://revistas.ufrj.br/index.php/oa/issue/view/2573
- Instagram: Vertebrate Laboratory (Laboratório de Vertebrados) of the Federal University of Rio de Janeiro (UFRJ) https://www.instagram.com/labvert_ufrj/
- Papers:
- Ferreira, M. S., Vieira, M. V., Cerqueira, R., & Dickman, C. R. (2016). Seasonal dynamics with compensatory effects regulate populations of tropical forest marsupials: a 16-year study. Oecologia, 182, 1095-1106. https://doi.org/10.1007/s00442-016-3735-x
- Ferreira, M. S., Kajin, M., Cerqueira, R., & Vieira, M. V. (2016). Marsupial population dynamics in a tropical rainforest: intraspecific competition and nonlinear effect of rainfall. Journal of Mammalogy, 97(1), 121-127. https://doi.org/10.1093/jmammal/gyv161
- Ferreira, M. S., Cerqueira, R., & Vieira, M. V. (2020). What are the main drivers of survival and recruitment in tropical forest marsupials? A 16-year study. Journal of mammalogy, 101(2), 515-525. https://doi.org/10.1093/jmammal/gyaa013
- da Cunha, L., Ferreira, M. S., Cerqueira, R., & Namen, A. A. (2023). The effect of long-term climatic variability on wild mammal populations in a tropical forest hotspot: A business intelligence framework. Ecological Informatics, 73, 101924. https://doi.org/10.1016/j.ecoinf.2022.101924
- da Silva, R. C., Vieira, M. V., Cerqueira, R., & Ferreira, M. S. (2023). Timing of birth determines lifetime survival in a Neotropical marsupial. Mammalian Biology, 103(3), 255-264. https://doi.org/10.1007/s42991-023-00352-9
Discover more posts from our Fieldwork Diaries blog series here.
