At high elevations of the tropical Andes, the cloud forests give way to high elevation puna grasslands. We have a nice new paper out in Environmental Research Letters (led by Imma Oliveras), which examines for the first time the productivity of Andean montane grasslands (or puna) and compares it with adjoining tropical montane forests. We find that the grasslands are just as productive as the forests, but have have very different carbon cycling and turnover properties. Here is the abstract
We aim to assess net primary productivity (NPP) and carbon cycling in Andean tropical alpine grasslands (puna) and compare it with NPP of tropical montane cloud forests. We ask the following questions: (1) how do NPP and soil respiration of grasslands vary over the seasonal cycle? (2) how do burning and grazing affect puna productivity? (3) if the montane forest expands into the puna, what will be the resulting change in productivity? The study sites are located at the South-eastern Peruvian Andes; one grassland site and the forest sites are in Wayqecha biological station, and another grassland site in Manu National Park. At each grassland site, we selected a burnt and an unburnt area, installed unfenced and fenced transects in each area, and monitored above-ground productivity (NPPAG), below-ground productivity (NPPBG) and soil respiration (Rs) for 2 yr. In the forest, we monitored NPPAG, NPPBG and Rs for 2–4 yr. Grassland NPP varied between 4.6 ± 0.25 (disturbed areas) to 15.3 ± 0.9 Mg C ha−1 yr−1 (undisturbed areas) and cloud forest NPP was between 7.05 ± 0.39 and 8.0 ± 0.47 Mg C ha−1 yr−1, while soil carbon stocks were in the range of 126 ± 22 to 285 ± 31 Mg C ha−1. There were no significant differences on NPP between the puna and forest sites. The most undisturbed site had significantly higher NPP than other grassland sites, but no differences were found when relating grazing and fire at other sites. There were lower residence times of above-ground biomass compared to below-ground biomass. There was a strong seasonal signal on grassland NPPAG and NPPBG, with a shift on allocation at the beginning of the austral summer. High elevation tropical grasslands can be as productive as adjacent cloud forests, but have very different carbon cycling and retention properties than cloud forests.
The paper can be downloaded here:
Oliveras I, C Girardin, C E Doughty, N Cahuana, C E Arenas, V Oliver, W Huaraca Huasco and Y Malhi (2014) Andean grasslands are as productive as tropical cloud forests Environ. Res. Lett. 9, 115011 doi:10.1088/1748-9326/9/11/115011
Here's a little interview video I did for the MSc class in Biodiversity, Conservation and Management, on how I go about writing a research grant proposal. The example is based on my European Research Council Advanced Investigator Award, GEM-TRAIT
Here is the panel discussion that took place at the Oxford Martin School on 18th November, around the new book "Is the Planet Full" that the panelists contributed to.
Here is the videocast of my October lecture on the macroecology and metabolic history of humanity.
I have just returned from a week in the Valdivia region of Chile, as part of a collaboration with the Universidad Austral de Chile funded by the Chilean Government funding agency CONCYT. This is a collaboration led by my host Antonio Lara (professor at the Universidad Austral), with a key part played by Rocío Urrutia, who is in the final months of her DPhil at Oxxford working on the carbon dynamics and historical responses of growth in the unique Fitzroya forests of this region. Southern Chile is a spectacular and lush green land , washed by frequent rains that roll in from the Pacific and into the coastal and Andean mountain ranges (though I have been blessed by perfect blue skies and bright sunshine on both my visits here). And everywhere you go you get the occasional and unexpected glimpse of perfect volcanic cones, that line up neatly along the length of this region. Here are a selection of photos of this landscape and this project (from both last week and from my previous visit in March 2012).
Last week I spent a few days with my family in the spectacular and relatively little-visited country of Oman. Here are a few pictures of this breathtaking and welcoming country, a real secret gem and an oasis of calm in the Middle East.
Here is a nicely-produced "Hay-Level" video talk I gave on humanity and the biosphere, after my talk at the Hay Festival in May 2014, on the metabolism of a human-dominated planet:
As Peru quietens down (see last post), Ghana ramps up in our quest to sample across the tropics. The plant traits campaign in Ghana, KWAEEMMA, has moved north, to the Kogyae site where plots straddle the transition between forest and savanna. Here are some photos taken by Allie Shenkin over the last two weeks.
Last month saw the end of our six month traits and ecophysiology campaign in Central and NE Peru, along an elevation gradient comparable to the one we sampled in SE Peru last year in the CHAMBASA campaign. The work involved a Peruvian team (many of the same people involved in CHAMBASA last year) coordinated by Norma Salinas and Lisa Bentley. This time the work was funded by the T-FORCES project, a European Research Council Advanced Investigator award to Oliver Phillips (Leeds) in which our Oxford group is a team member. Oxford's main role is to coordinate ecophysiological studies along elevation transects in Peru (2014), Australia (2015) and Africa (2016), which will complement other traits campaigns we will have conducted (or will conduct in Brazil, Ghana and Malaysia).
Photos by Percy O. Chambi Porroa, Cristian Costas Pacheco and Flor María Pérez Mullisaca, Milenka Ximena Montoya, Paul Santos Andrade and Rudi Saul Cruz Chino.
Yadvinder Malhi is an ecosytem ecologist and Professor of Ecosystem Science at Oxford University