The rainy afternoons this time of year create some amazing rich green colors in the forest. As the rainy season continues there is good reason to visit this area if you don’t mind a little moisture. The lushness of the forest, swelling rivers, and dramatic waterfalls are all a sight to see.
Research and Volunteers:
Cléa Lefevbre from AgroParisTech in France just finished a forestry internship with us where she was examining the differences in forest structure between planted and naturally regenerating (NR) forest of the same age. She also did some general comparisons with old growth forest. She found that planted forest had a linear relationship when plotting tree height against diameter at breast height (DBH), while NR forest had an exponential relationship. She thought this was because the trees in the planted area are planted at least 2 m from each other and the vegetation cleared so the young trees don’t have to compete with each other or other plants so can can grow at a steady rate. In the NR forest, the young trees have to compete for light so focus initially on growing tall to capture the light. Once that is achieved they then will start to increase their girth.
She then looked at the distribution of trees across 5 size classes (seedling, sapling, small tree, medium tree, and large tree). She found that the plantation forest had a large number of trees in the sapling category, no large trees, and few seedlings. While the NR forest also had a large number of sapling trees, it had a much larger number of seedlings and a few large trees, a structure more similar to the old growth. This means that recruitment is lower in the plantation area, which could lead to issues in the event of a disturbance in the forest (ex. blow-down, landslide, etc.).
Her plots will be used in future years to continue to monitor the differences between the two forest types as they age and it will be interesting to see how things change over time!
Catherine Walker, Elle Boone, Kelsey Davies, and Harriet Tyson from Exeter university in the United Kingdom finished a 6 week study on ant diversity and distribution in Cloudbridge. They wanted to study ants as they are the forest’s caretaker’s, cleaning up dead material, and can be used as bioindicator’s of reforestation success. Using pitfall and baited traps (tuna and sugar water) to collect the ants, they studied 3 forest types: planted (<15 years), natural regeneration (>30 years old), and old growth forest (70+ years old). They were able to identify the ants down to at least genus and many also to species. When comparing overall abundance and species richness, there was no significant difference between the habitats, which is a good sign for the effectiveness of our reforestation efforts. However, when looking at the similarity of the abundance of each genera present in the different habitat types (Bray-Curtis), they found that the planted and naturally regenerated habitats were moderately similar (0.5), while natural regen compared to old growth was lower (0.3), and planted compared to old growth was the least similar (0.1). Further analysis is being done to see if there were certain genera specific to each habitat and what that means for our forests.
Alena Frehner from Van Hall Larenstein in the Netherlands completed her camera trap study in July. She used camera trap data (6 locations) and habitat data she collected to examine habitat factors that may affect the abundance and species richness of animals around the camera traps. The habitat factors she looked at included: habitat type (old growth, naturally regenerating, or planted forest), canopy closure, difference in slope of trail compared to the surrounding landscape, and tree size (when looking at arboreal and semi-arboreal species only).
She found that while species richness was not significantly different between the camera trap locations, abundance was, both when looked at as individual locations (with two of the sites showing higher than expected abundance and the rest lower, p=0.00) and when locations were grouped into habitats (with natural regenerated and planted forest having greater abundance than expected and the old growth lower, p=0.00). When examining the other habitat factors, none of them were found to have significant relationships to either species richness or abundance on the camera traps.
However, when looking at tree size (average, median, and max tree height; and median DBH) and abundance of arboreal and semi-arboreal species, with the exception of one outlier, there appeared to be a positive relationship between abundance and height, and a negative relationship between abundance and median DBH. The outlier was location E1, which also had a much higher abundance of animals than expected, and was by far the most productive camera trap location. E1 is located at a pinch-point along a ridge trail, where a large boulder and dense vegetation force most animals to walk along the trail, and therefore in front of the camera, making it more likely that the camera will capture images of animals in the area. Because of this, E1 may be skewing the data and not be a true representation of habitat choice as the animals in that location have little choice but to walk in front of the camera. As such, the examination of tree size and presence of arboreal and semi-arboreal animals on the camera traps warrants further investigation.
As part of her work on the index, she collected samples from trees to better identify potential sloth trees and took them to the national herbarium for help confirming the identifications. As a result of this work, they identified 3 new species for the reserve!
Introducing a new volunteer – Marissa Romp
Hola amigos y amigas,
‘The earth has music for those who listen.’ This quote is one of my favorite quotes of all time because it catches my thoughts and inspires me to take decisions in life that contribute to this ability and creates that possibility. My name is Marissa, I am 27 springs young and am currently studying Wildlife Management in my home country – The Netherlands. Although I am still wondering ánd wandering about what profession I want to engage in, I am the happiest surrounded by forest, its inhabitants and the beautiful music they make. As part of my study I have worked at an Animal Ambulance to transport wounded or neglected animals. Last year I conducted a behavioral study on Samango monkeys in the province of Limpopo, South-Africa. After returning back to the Netherlands I knew something was missing. This experience of living in basic conditions – compared to my Western upbringing – and surrounded by the beauty of the forest has ignited a little spark of wanting to go abroad again. Hence next adventure; Costa Rica. I choose to do my internship at Cloudbridge because of the remoteness, the presence of two of my favorite species (White-faced capuchin monkey and the Geoffroy’s spider monkey) and the chance to surround myself with people passionate about the conservation of the forest and its wildlife. Here, I am currently engaged in a new mammal study which recently started for a period of five months. The aim is to set up a mammal species list and to see whether there might be any differences in mammalian species diversity between the different habitats present at Cloudbridge Nature Reserve. I am extremely excited to find out what the results will be. Pura vida!
New Research Report Now on Our Website:
Two new reports have been added to the website this month. Check them out and many other reports on the research done at Cloudbridge on our publications page (http://www.cloudbridge.org/publications/reports/).
We do like to have fun. Its not all work. Sometimes there is a little rumble in the jungle for birthdays on the reserve.