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Herbivory in the Amazon Rainforest of the Napo River Basin

Historically, herbivory studies have been done from the ground, with
most samples taken at an average height of two meters. Any
extrapolation from this data fails to take into consideration both the
vast difference in the amount of foliage above the forest floor and the

different herbivorous species found only in the upper canopy. (Lowman,
2012/2) A solution to this dilemma is to take samples from canopy
walkways and platforms. The Amazon Conservatory for Tropical Studies
in the Napo River Basin in Peru contains one of the longest canopy
walkway systems in the world, extending horizontally 500 meters
throughout the tree-tops and reaching a maximum height of nearly
35 meters. (ACTS, 2016) The forest canopy fixes solar energy in
carbohydrates, which are used to power interactions among forest
components that, in turn, affect regional and global climate,
biogeochemical cycling, and ecosystem services. (Lowman, 2012/1) 
Looking at the energy functions of the entire tree, instead of just the
forest understory, has led to the discovery of millions of new species,
greatly expanding understanding of global biodiversity. The complex
three-dimensional structure of forest landscapes often requires
individual researchers to focus only upon a subset of the whole forest.
(Nadkarni, 2004) The vertical gradient is a defining feature of all forests.
The height of the canopy and tree size causes microclimates and

individual biotic communities to be more obviously vertically
organized. (Shaw, 2004) To see the forest for the trees, one must first
understand the trees.

The project herein looks at herbivory in the Amazon rain forest,
specifically the Napo RiverBasin, Peru. It charts the average herbivory
of different species at different heights. The analysis will focus on
mapping different heights of samples taken and the differing amounts

of leaf matter devoured through herbivory. This paper will focus on
herbivory of fourteen different plant species: Grias peruviana (cocora);
Spondias purpurea (jocote); Erythrina edulis (pajuro); Brosimum
allacastrium (breadnut); Atsophilla spp.(ferns); Rinorea falcata

(wild coffee); Inga edulis (guaba); Eschweilera sp. (mata-mata);
Oxandra xylopiodes (cimmaron); Parkia pendula (tamarindo);
Viroles spp. (cumala); Pterocarpus santalinoides

(mututi); Jacaranda mimosifolia (jacaranda); Schefflera spp. (starleaf).

In addition to the traditional overhead map of the area, vertical
mapping of the canopy and sample areas will be done. Profile graphs
of the various tree heights and points of sample acquisition will be
mapped. This will help to garner a better understanding of the entire
forest, not just the ground or the upper canopy. Since the analysis will
be made on vertical data, the technical approach will focus on a spatial
series across different trees. The methodological concept is that of
variation over a series.

The data was collected by Dr. Meg Lowman in the late 1990s, utilizing
trees along the ACTS walkways of the Peruvian Amazon. The leaves
were sampled manually along walkways and raised platforms that form
permanent structures maintained by ACTS. The collected data indicates
the amount eaten for 10-30 leaves of different species at different heights.
From this information, it is possible to estimate the herbivory of the entire

250,000-acre forest, if the ratio of species throughout the forest is known.

References

American Conservatory for Tropical Studies (2016) ACTS Peru

https://actsperu.wordpress.com/ Accessed on 5.21.2020.

Lowman, M., and T. Schowalter. (2012) Plant science in forest canopies –
the first 30 years of advances and challenges (1980–2010). New
Phytologist 194: 12–27 doi: 10.1111/j.1469-8137.2012.04076.x

Lowman M., T. Schowalter, and J. Franklin. (2012) Methods in Forest
Canopy Research. Berkeley: University of California Press. Especially
pp 93-98.

Nadkarni, N., et al (2004) The Nature of Forest Canopies in Forest
Canopies. Boston: Elsevier Academic Press, pp 3-23. 

Neyret, M. et al (2016) Examining variation in the leaf mass per area
of dominant species across two contrasting tropical gradients in light
of community assembly. Ecology and Evolution 6(16): 5674– 5689

doi:10.1002/ece3.2281

Shaw, D. (2004) Vertical Organization of Canopy Biota in Forest
Canopies. Boston: Elsevier Academic Press, pp. 73-101.