I’m rattling down an unpaved road in the Ecuadorian Amazon. The brakes screech at every turn, and the chain is close to falling off. Unsurprisingly, the rain is pouring, turning the road into a maze of puddles and mud. The road follows the Anzu River, and I can hear its roar off to my right.
I’m forcing a perfectly innocent bike to brave the Amazon because this road leads to the Herbario Amazónico of the Universidad Estatal Amazónica (ECUAMZ). ECUAMZ (an acronym for “Ecuador Amazon”) is the only herbarium in the Amazon, and contains a repository of plant specimens for preservation and help with field identifications. It was established by Dr. David Neill, a specialist in the Fabaceae (legume) family and world-renowned expert in tropical botany, and Dr. Mercedes Asanza, the coordinator of the herbarium. They have agreed to mentor me over the summer and teach me about tropical plants. The Herbario Amazónico, which contains over 17,000 vascular plant species, is the perfect place to learn.
The view from the top of the tower at Jatun Sacha.
When I first heard about this class in Peru, I had no idea that I was going to experience so much in such a short period. Our goal was to visit two lakes in Peru and raise sediment cores for paleoecology. The first lake that we went to was Laguna Huayabamba, which sits at about 3250 m elevation in the La Libertad region of the Peruvian Andes.
However, getting to this lake was no easy task. Before the hike even started, we had to obtain the necessary permits and permission from the local people. After several days of visiting different town officials and waiting for approval, we could set out on our adventure.
This time you are reading a message from a non-expert in paleoecology. My name is Masha and I will spend the next two years on a very exciting postdoctoral fellowship funded by NWO (Dutch National Science Foundation) under their Rubicon scheme in close collaboration with William Gosling (University of Amsterdam).
Valencia Castillo, B.G. (2014) From glacial to modern conditions: Vegetation and climate change under human influence in the Central Andes. PhD Thesis, Department of Environment, Earth & Ecosystems, The Open University.
Conservation, restoration and management strategies are employed to maintain Earth’s biological diversity and physical environment to a near “natural” state. However, the concept of “natural” is generally inexact and may include degraded landscapes. In absence of long-term empirical data of natural baselines, impacted assemblages (human altered baselines) could be falsely assumed to be natural and set as conservation or restoration goals. Therefore, the identification of long-term ecological baselines becomes a pressing requirement especially in threatened biodiversity hotspots such as the tropical Andes that were under human pressure for several millennial.
This thesis aims to identify ecological baselines for tropical Andean ecosystems based on multi-proxy palaeoecological reconstructions from three Andean lakes. Trends of vegetation change are used to identify when landscapes became anthropogenic in the Andes. Because vegetation assemblages at c. 10 ka experienced negligible anthropogenic impacts and had modern-like climate condition, this time was considered the most recent period likely to provide insight into natural ecological baseline conditions.
Changes in vegetation assemblages were evaluated over time departing from 10 ka around Miski and Huamanmarca, two sites that remained virtually impervious to human impacts. Baselines in Miski and Huamanmarca drifted continuously over time and showed that baselines are dynamic entities. The vegetation assemblages derived from Miski and Huamanmarca suggest that that human impact was not homogeneous throughout the Andean landscape.
Once baselines were defined it was possible to evaluate if the spatial distribution of Andean woodlands represented by Polylepis was a product of human impacts. A MaxEnt model generated based on 22 modern environmental variables and 13 palaeoecological vegetation reconstructions showed that Polylepis woodlands were naturally fragmented before humans arrived in South America (14 ka). However, the influence of humans during the mid and late Holocene enhanced the patchiness of the forest generating a hyper-fragmented landscape.
To facilitate the our ability to identify pollen in the fossil record we have been building a searchable digital tropical pollen database. Our work builds upon the architecture provided by Bush & Weng (2007) for their Neotropical pollen database (Palaeoecology lab, Florida Institute of Technology). We have used Bush & Weng’s freeware tool and expanded it to include an additional 364 pollen and spore types from tropical Africa. The images are of pollen reference material collected over the career of Prof. Dan Livingstone and curated in the Department of Biology, Duke University; full collection details of each specimen are indicated on each individual electronic record. In conjunction with the open access publication “Atlas of the tropical West African pollen flora” (Gosling et al., 2013) we have made the entire updated pollen database available. We hope that this will prove to be a useful tool for palynologists working in Africa and the wider tropics and that it will encourage others to develop the database further.
Extracting data from tropical pollen records can be difficult, and time consuming, because of the high floristic diversity. Ecology of the past contributor and PhD researcher Bryan Valencia has developed a method for turning your computer into a tally counter. Bryan’s method allows the easy recording of diverse assemblages, and saves time on data entry. The tally counter can be used to count whatever you like…