ATDN goes composition
With funding from the Alberta Mennega Stichting and the Stichting het Van Eeden-fonds we are now adding composition to the plots of ATDN. After the PhD project of Olaf Banki 155 plots of the Guianas and Venezuela were added. Juliana Stropp added her own plots and those of Brazilian collegues and brought the number at c. 200. At this moment the count is just over 300.
It was interesting to see that 200 plots in eastern Amazonia generated 2000 fully identified species and another 2000 morpho-species, that could not be identified at the species level. Thus, 200 ha (or 2 km2) of eastern Amazonian forest may already contain some 4000 species! As the total Amazon forest spans between 5 - 6 million km2, we can wonder if the 12,500 species for the total Amazon (Hubbell et al 2009) is not an underestimate?
In any case our example also shows how little we still know of this area, how little data we have, and how poor our level of identification is at this moment.
Towards an understanding of tree diversity in Amazonian forests
Juliana Stropp Carneiro (2011), PhD thesis, Utrecht University
Amazonian forests harbor the highest biodiversity of all terrestrial ecosystems on Earth. The origin of this extraordinary biodiversity and its current distribution are recently becoming better understood. Still, our knowledge of the contribution of processes operating at different temporal and spatial scales to the tree diversity in Amazonia remains surprisingly limited. This thesis aims at deepening our understanding of tree diversity in Amazonian forests and the ecological mechanisms shaping its current pattern at a local and regional scale. By analyzing tree inventory plots established across Amazonia, we found that areas with high regional diversity coincide with areas of palaeo-climatic stability and long-term high ecosystem dynamics. As these two factors affect speciation and extinction, and shifts in species distribution, we propose that they are important drivers of the current regional tree diversity. Variation in tree diversity at the local scale is enormous but poorly explained by local disturbance. We suggest that the power of this explanation is low because local tree diversity is subject to various local processes, which are largely variable from one location to another. We investigated, in further detail, tree communities of white-sand and terra-firme forests, which have a relatively independent evolutionary history. We analyzed tree inventory plots established in white-sand and terra-firme forests in the upper Rio Negro. We found that tree communities of white-sand forests show a higher floristic similarity and lower diversity than those of terra-firme forests. Furthermore, we tested the hypothesis that a trade-off between seedling growth and herbivore defense drives habitat association. We found no evidence that this trade-off drives habitat association in these forests in the upper Rio Negro. This finding may be explained by the extreme low nutrient availability of the soils in this region, which may cause seedling mortality in their non-typical habitat and restrict seedling growth. Finally, we characterize the tree communities of white-sand and terra-firme forests in three Amazonian regions. We assessed how regional tree communities regulate the variation in local tree communities of white-sand and terra-firme forests. Furthermore, we assessed if habitat association is maintained across lower taxonomic levels. We found that local tree communities of white-sand forests in central Amazonia are more diverse than those occurring in the large white-sand areas of the Guianas and the upper Rio Negro. We found that most families and genera, which are significantly associated with either forest type, have the majority of their species associated with that particular forest type. This finding suggests that a large number of species have retained requirements for their typical habitat during speciation events. Taken as a whole, our findings indicate that tree diversity can only be understood if both long-term evolutionary and current ecological processes are taken into account. At long-term, the size of forest areas in Amazonia is expected to decline in response to a predicted drier climate. At short-term, ongoing deforestation reduces the size of forest areas. As deforestation occurs at such rapid rates, long-term species adaptations to new environmental conditions may be of minor importance for the future of Amazonian forests
Mar 2011, Mega update of ATDN website and diversity maps
After a long silence the ATDN website has received a large update, filling many information gaps. My apologies for the long wait. At this moment the ATDN database holds just over 900 plots - of course we hope to hit the 1000 barrier sometime soon.
What is new?
- updated news, and publications
- New list with publications with plot records
- R-code to calculate Fisher’s alpha
- A Google Earth Plug-in with location and information of all ATDN plots
- More downloadable material - especially publication ready maps
The new update has been made possible by grants from the Alberta Mennega Stichting and the Stichting het Van Eeden-fonds.
Since the mega-update in February 2011 many things have happened.
Sad news arrived us that Samuel Soares de Almeida passed away April 1. Samuel contributed several plots to ATDN. He was of key importance to the Caxiuana site and floodplain forests in the Amazon. We will surely miss his input and presence in forest and lab.
One new member was added. Ophelia Wang contributed 3 new plots from Ecuador.
Juan Carlos Montero and Florian Wittman contributed 11 Igapo plots added from Middle Rio Negro.
Dairon Cardenas contributed 10 new plots from Colombian Upper Rio Negro Area (Inirida).
18 plots have been added from Rainfor public domain plots.
Several new plots were found in the literature; Guyana, Kaieteur Falls, 2 plots (Kellof 2008); Brazil, Amana, 3 plots (da Silva Machado 2010); Brazil, Tupe, 1 plot (Diniz and Scudeller 2005), Brazil, Amapa 10 floodplain plots in Amazon estuary (Leite de Quieroz 2008).
The number of plots now stands at 985.
ATDN passes the magical 1000 plots border
Several plots have been added since the 2011/06 update and this week we recorded the 1000th plot. All plots have been added from publications not used so far: 3 plots in Para (Ferreira et al 2010, Batista et al 2011); 2 plots on the Amazon border (Mato Grosso, Kunz 2007); 2 plots in Dreserva Ducke (Brito 2010); 2 plots in Tocantins (Brito et al 2008); 9 plots in Peru (de Freitas 1996a,b); 2 un-used plots in San Carlos de Rio Negro (Uhl & Murphy 1981); 1 plot in Sucumbios, Ecuador (Ceron & Reyes 2007); and 2 samples from varzea near Belem (Jardim et al 2001).
The total number of plots is now 1004!