Acknowledgements
“All data in this publication were provided by the Tropical Ecology Assessment and Monitoring (TEAM) Network, a collaboration between Conservation International, the Missouri Botanical Garden, the Smithsonian Institution, and the Wildlife Conservation Society, and partially funded by these institutions, the Gordon and Betty Moore Foundation, and other donors.”
Data creators:
Introduction
The Central Suriname Nature Reserve (CSNR) is a protected area of 1.6 million Hectares, with a wealth of biodiversity. The CSNR is located in the Amazon forest, and the preservation of biodiversity in this area is of a high priority both nationally and internationally.
This brief explores the spatial distribution of one Genus in the dataset: Astrocaryum and one Family, Lecythidaceae.
Data
The dataset, downloaded from Tropical Ecology Assessment and Monitoring (TEAM) Network consists of information on trees, lianas and climate variables. The trees dataset consisted of various 1ha plots, each at different elevations for the years: 2010, 2011, 2013, and 2015. The plots are denoted as: “VG-CSN-1”, “VG-CSN-2”, “VG-CSN-3”, “VG-CSN-4”, “VG-CSN-5”, and “VG-CSN-6”. Each plot is associated with a specific elevation and the same plot is sampled at each successive sampling period. The number of species described in the dataset is 148 (132 Genera).
Understory tree: Genus Astrocaryum
Trees from this genus are characteristically palm trees with edible fruits and are of value to indigineous peoples of the Amazon for creating black rings. These rings are considered as a sign of friendship and commonly used by religious groups as a symbol of solidarity to the poor.
Contour map for elevation for location of Astrocaryum plots
The trees for this genus were sampled at various elevations (See Figure 1 below). The darkest regions are relatively lower in elevation.
Spatiotemporal distribution of trees of Genus Astrocaryum at plot VG-CSN-3.
The diameter (cm) of each tree is denoted by colour. Over the years for which this genus was sampled it is noted that there are more trees with larger diameters in 2015 than in previous years. There are also a few new tree locations observed in 2015 (See Figure 1).
Spatiotemporal distribution of trees of Genus Astrocaryum at plot VG-CSN-2.
The diameter (cm) of each tree is indicate by a distinct colour. Most of the trees in this plot appear to be relatively larger in terms of diameter than those in plot VG-CSN-3.
Lecythidaceae (“Brazil nut family”)
Trees of this Family are considered to be abundant in the Amazon (ter Steege et. al, 2006) and contain 10 genera and 310 species. The figure below illustrates the spatial distribution of trees of this family by plot for the year 2015. The different species per plot are indicated by a distinct colour.
Trees of this family have been identified by Conservation International (2010) in the high tropical rainforest (on terra firme) region in the CSNR and also at CSNR tropical forest on laterite/granite hills and palm swamp forest sites.
Only two of the sampled plots contain multiple species.
Focusing on plot VG-CSN-3
This plot contains four regions/clusters of relatively high density of trees (see Figure 5). The blue areas in Figure 5 represent the areas of low density. Figure 6 shows the pair correlation function (a secondary point pattern metric) for Lecythidaceae plot VG-CSN-3 (in 2015). In Figure 6, the pair correlation function observed for the data gives a preliminary indication that the trees in the plot exhibit a clustered pattern relative to that obtained for a random reference point pattern. The thick black line in the figure denotes the pair correlation function for the plot, and the green dotted line denotes what would be expected if the point pattern (data) was obtained by inputting random locations for the trees.
Further analyses would be necessary to infer whether this remains true when a simulation envelope is constructed for the pair correlation function and whether a similar result is obtained for each species involved.
Modelling, and software
The software available to modelling the spatial distribution of mulitple ecological groups is confined to modelling the interaction between a pair of tree groups (for example, two species) under the assumption that their interaction with each other is negataive; that is, they inhibit each other.
There is a need for the development of methods to model
- the interaction between multiple groups (with more than two groups) simultaneously,
- in the presence of covariates such as environmental change, and
- lianas (climbing vines typically found in rainforest).
References
ter Steege, H., Pitman, N. C. A., Phillips, O. L., Chave, J., Sabatier, D., Duque, A., Molino, J.-F., Prévost, M.-F., Spichiger, R., Castellanos, C., von Hildebrand, P. & Vasquez, R. (2006). Continental-scale patterns of canopy tree composition and function across Amazonia. Nature 443: 444 - 447.
Conservation International, 2010,A Rapid Biological Assessment of the Kwamalasamutu Region, Suriname https://www.conservation.org/docs/default-source/publication-pdfs/rap_preliminary_report_kwamalasamutu_suriname_august-september_2010.pdf?Status=Master&sfvrsn=f43fa454_3