One of the great things about doing fieldwork is that in addition to the focus of your visit you get to learn and see many new things. Currently I have been in Bolivia as part of a Darwin Initiative project to promote sustainable Inga based agroforest techniques with local farmers, so being in the Amazon forest, this is probably more so.

While introducing ourselves to one of collaborating community, Motucusal, in a cleared area of forest that serves as their meeting room we noticed a really strange phenomenon that none of us, including our hosts, had seen before. It was a small swarm of ants swirling around a small group of their own in a clockwise direction at speed (see the film below).

At first we thought that they could be protecting an entrance hole to their nest, or invading somebody else's nest, but on disturbing them there was no hole and they returned to what they were doing straight away. So, as far this botanist goes, it's still a complete mystery.

Swirling ants

Completely by chance the next day, visiting the community of Palacios we several swarms of tadpoles in a large lake by their village. Again it is not really clear what they are doing but it looked as if they were skimming the surface, maybe for food?

A swarm of tadpoles in a lake at Palacios

And below is another phenomenon well known for the Amazon, white and black water rivers. Black water rivers are those where all of the water is derived from the Amazon basin itself, the water aquiring a dark tea-like colouration as a consequence of the tannins it absorbs as it filters through the leaf-litter. In a way the Amazon is a bit like am enormous tea-making facility! White water is rich in sediment derived from the weathering of the Andes and is an opaque white-coffee to orange-brown colour. This phenomenon means that wherever you are you can tell whether a river derives solely from the Amazon basin or whether it also includes water from the Andes, an incredibly powerful but simple tool for any biogeographer (which I am not). Below you can see what happens where the two mix, over several hundred metres to kilometres you get two parallel streams of dark and white water which mix very slowly. The slowness in mixing is in part because each water is at a different temperature: white water reflects more energy from the sun whilst black water absorbs it.

Mixing of white and black water rivers at the head of the Orthon river

When I joined Kew on secondment as a botanist last year I hadn't really expected to be negotiating the sourcing and planting of ca. 25,000 tree seedlings in the Bolivian Amazon. Many possibilities went through my mind, but not that one. That is what makes being a botanist so much fun! Contrary to the stereotype, you never know where your knowledge and contacts will lead you next.

Terry Pennington, Bente Klitgaard and myself are now in the Bolivian Amazon as part of a Kew Garden's Darwin Initiative project to reduce pressure on the incredibly biodiverse forests of the Bolivian Amazon, amongst the richest in Amazonia.

The opening of new roads - an initiative by the Bolivian Government to give land to the landless rural poor of the Andes - and pressure on the land from Brazil are important threats to the future of much of the forest. Devising approaches to agriculture and forest use, and raising awareness of the economic and ecological value of these forests are tools that can reduce and mitigate some of these threats.

View from the air of the Cobija area of the Bolivian Amazon.

As part of this aim we plan to introduce a very old but largely abandoned type of agroforest farming based on a group of trees in the bean family known as Inga. These trees grow very quickly (3m in the first year) and are able to tolerate very damaged and degraded soils such as those found in cattle farms or abandoned soya or pineapple plantations. These forms of farming are very profitable in the short-term but soon exhaust the ancient soils often found in the tropics and on which the tropical forest grows.

The result is that a farmer or agribusiness needs to clear forest on a regular basis to maintain an economic yield and leaves degraded pasture, a kind of grassy desert, in its wake. What we are aiming to do is provide a technique whereby farmers can restore this exhausted land to productivity, for growing food, fruit trees, cash crops, timber or even fodder and at the same time obtain a plentiful supply of fuelwood for cooking. This is known as Inga agroforest.

Left: A two-year old Inga tree near Cobija. Right: Inga fruit with seeds below (click images to see them full size)
Inga has a pod within which are seeds (green) covered in a white, fluffy, very sweet and juicy flesh. The tree is commonly grown for its fruit but also has tremendous potential for the restoration of degraded land in Latin America, as it is very fast growing and tolerant of damaged soils.

The Inga agroforest approach involves planting dense alleys of Inga seedlings spaced several metres apart and letting them grow for 2 years, by which time they are about 6 metres tall (see photo above). Then all their branches are removed and a crop of beans, cassava, maize, Cacao or whatever is wanted is planted.

The Inga branches grow back very quickly and need to be cut every 6 months, providing a valuable source of fuel wood for cooking. The key to this system is that once the Inga trees are about 6 metres tall their side branches meet and so completely cover the alley, thereby suppressing weeds. And, just as importantly, they generate a rich leaf-litter that forms the basis of a nutritious soil for whatever crop is to be planted subsequently.

So far we have identified a number of trees that could act as sources of seed from three or four species, including one community that could probably provide all of the seed that we need, a good sign for our first day out in the field!

Since September 2012 Anaité López (Instituto Nacional de Bosques, Guatemala), Tim Marks (Millennium Seed Bank) and Wolfgang Stuppy (Millennium Seed Bank, do visit his amazing blog) have been working at the Millennium Seed Bank to develop a long-term storage protocol for the seed of the Maya Nut tree (Brosimum alicastrum).

This is important because Maya Nut is a significant famine food for the rural poor in northern Central America and is being actively used in reforestation projects as it is fast growing and relatively tolerant of disturbance.  At the moment, however, it is not possible to store the seed for more than a couple of weeks making it very difficult to deploy seed as and when it is needed outside of the fruiting season.

Left: Maya Nut (Brosimum alicastrum) fruit - Fruit as it is when still on the tree

Right: Maya Nut (Brosimum alicastrum) seed - Seed once stripped of the fleshy outer layer by bats or birds (left), with both papery coverings removed (centre), with only the outer of the two papery covering removed (right)

The work involved collecting about 5,000 seeds from Maya Nut forests in the Peten of north eastern Guatemala. The seed was then shipped to the Millennium Seed Bank by courier where it was unpacked and studied by Anaité who had flown over from Guatemala for six weeks to undertake the work under the supervision of Tim Marks and Hugh Pritchard, specialists in seed research and storage. This was an opportunity for her to take back the skills and knowledge that she had learnt to Guatemala. The work has been funded by Defra through the Darwin Initiative (project 18-010) and is taking place incollaboration with the Maya Nut Institute.

A batch of Maya Nut seeds being germinated following controlled storage. Image courtesy of Anaité López.

Our plan was to devise a regime of cooling and drying the seed that would enable it to be cryogenically stored (frozen) and so stored for many years. To do this we needed to identify the best rate at which to drop the temperature and humidity whilst keeping the seed viable. This involved storing the seed at different temperatures and humidities and taking a batch out and germinating it every month.

Given that this seed does not survive for long in the wild and that it is protected by two very thin, papery coverings (see above) we expected it to be very prone to dessication and so sensitive to low humidity. In fact we found quite the reverse. Six months later we are still germinating seed that has retained most of its moisture after having being stored in a dessicant for all this time!

In order to understand how this could happen we contacted seed morphologist Wolfgang Stuppy, world expert on seed morphology. He made the following images of sections through the seed which show a thin but dense layer of cells that control waterloss from the seed:

Section through Maya Nut seed showing the dark outer layer that might reduce water loss. Image courtesy of Wolfgang Stuppy.

So we now have a partial explanation as to how the seeds can show such remarkable tolerance to drying out. It does, however beg two questions:

1. Why do seeds not survive under the conditions of the forest floor?
2. Why would a tropical tree that grows in the humid tropics develop such a remarkable resistance to drying out?

To be continued maybe...

Tonya Lander (Life Sciences, The Natural History Museum) has just completed her analyses of the population structure of the Maya Nut tree (Brosimum alicastrum). The results are based on the use of genetic markers and are really interesting. They tell us something about not only the history of this species but how best the species can be managed. This is important because Maya Nut is a significant famine food for the rural poor in northern Central America and is being actively used in reforestation projects as it is fast growing and relatively tolerant of disturbance. The work has been funded by Defra through the Darwin Initiative (project 18-010).

Brosimum alicastrum forest in Mexico

Female flower of Brosimum alicastrum

The tree is relatively common throught Central America and South America north of the Amazon. The markers that we have used are from the chlroroplast and nuclear ribosome genomes of the plant and were collected from 34 populations across Central and South America. Many of the samples were collected by the women who harvest the Maya Nut. which provided us with the opportunity to connect rural communities with scientists the other side of the World.

Tonya's results provide evidence for distinct northern and southern genetic types (Figure 1), and possibly for Atlantic and Pacific genetic types (Figure 2). These results still need to be tested for statistical significance but will help to clarify whether B. alicastrum fits into the broadly recognized historical pattern of retreat into the Amazon basin during the last glacial maximum followed by post-glacial expansion north into Central America. Each grouping represents a potential land race or ecotype and if confirmed will represent the framework within which seeds can deployed for reforestation.

Figure 1. Five distinct sub-groups of Brosimum alicastrum:  (1) Peru (dark pink), (2)Panama (bright pink), (3) ‘Southern’: Brazil,  Columbia, Panama, Nicaragua, Honduras, El Salvador, Belize, Cuba, Mexico  (light blue), (4) Costa Rica (dark blue), and (5) ‘Northern’: El  Salvador, Guatemala, Belize, Mexico (pale pink)

Arrived in Panama to collect populations of a widespread tropical tree known locally as Casique or Berba and scientifically as Brosimum alicastrum. The taxi driver to my hotel was quite old, his eyes well cataraxed and very grumpy. A little surprised but realising that taxi permits are probably applied as loosely as they are with respect to Mini Cabs in London I got in. Polite conversation resulted in me asking him how long he had been a taxi driver, "eighty years" he replied sullenly. "No I meant how long have you been driving a cab? Not how old you are" I replied. "I am 100 years old and have been driving a cab for 80". So there you have it, albeit self certified, I could have ridden with the oldest cab driver in the World!

Onto business today. We had to withdraw our collection permit and apply for an export permit. A bureacratic feast that took all day. It entailed visiting four offices, paying two fees, one at one office and one at an office the other side of town follwoing after an hours queue. Despite the need to fill out many forms and procedures, everybody I met was very polite, friendly and helpful. At the National Authority for the Environment office I was even given a desk and computer to write out some of the forms I had forgotten or didn't realise I needed. I would be very surprised if any Government Office in the UK would do the same for a visiting researcher. So a big thank you to Alexander Montero, Dario Luque and Israel Tejada of the ANAM Office!

As a consequence I made it to the National Herbarium quite late but with enough time to chat with Mireya Correa, legend in her own right with the Panamanian scientific and Neotropical botanical communities. She very kindly invited me to give a talk this Thursday but also mentioned that one of my collections from Panama in 2006 looks like it is a new species of Verbesina (Sun-flower family, Asteraceae). Below is a picture I took of it at the time of collection. I remember it quite well as I was surprised to see this genus including trees (below):

Below, a ship passing through the Panama Canal close to a potential collecting site for our project:

Our last day in the mountains. Mixed emotions really. We have made some great collections, enjoyed each other’s company (I hope), learnt a lot, had great support from our porters and field team and have been very lucky with the weather. We are a bit tired though and beginning to lose some of our enthusiasm. I even caught myself not being amazed at seeing a Quetzal so it is probably time for us to head home.

Oak forest at 8 in the morning, light streaming through the foliage

For me the highlight of the fieldtrip has been camping on top of one of the Cerros Tararias, almost certainly the first Europeans to have made it to the top of one of these 200 m high blocks of gneiss rock each with its mini paramó atop. Not only did we get the first plant collections from here but we also enjoyed spectacular views between Cerros Kamuk and Fábrega and down the valley of the Río Jet. A completely unexplored part of the Park and the focus of another trip should we get the funds.

View of one of the Cerros Tararias and out across to the Río Jet valley

Carlos ‘Leña’ and his son Josué. Carlos has been our guide and lead porter for much of our work in La Amistad Binational Park and has been a key player in our exploration of the Park.

It has also been a real privilege to be able to share some of what we have done and seen with visitors to the Museum as part of the Nature Live programme. For that a big thank you should go to Stephen Roberts and Jo Kessler from the Museum’s Nature Live team, Lee, Adam, Alex, Eddie, Ken and Tony from our Special Effects Department and Erica McAllister and Gavin Broad from our Entomology Department.

Also to Tom Simpson, who although was of course very lucky to come with us and whose feet in no way smell (no really they don’t), was incredibly professional and did everything possible to make sure that the live video links went well and answered as many of the questions on the schools blog as possible. Last but not least Jon from our Interactive Media team who has been assembling and editing this blog and to Grace from our Learning Programme who set up the events for schools.

Tom uploading his blog from the base of the Cerros Tararias

Our camp at the base of the Cerros Tararias

The plan today was to walk from our main camp at the Albuerge (see the map on Tom's blog) at 2,500 m to a smaller one, Casa Coca, at 1900 m so that tomorrow morning we can get back to the park entrance in good time for the eight hour drive back to San José. It was a beautiful sunny morning, the light streaming through the trees as we set off.

The plan was to interrupt our walk and sneak in a sample point half way, in the Pacific drainage. It was really amazing how dramatically the forest changed once we had crossed the main pide between the Caribbean and the much drier Pacific, the understory becoming more open and the canopy lower, possibly because of less rain and more wind?

Holger at the Continental pide collecting a sneaky lichen from the back of the Park sign

Scientifically the trip has been a great success, Jo Wilbraham made about 340 moss collections, Holger Thues about 500 lichen collections and Daniel Santamaría (from Costa Rica), Neil Brummit and myself about 640 vascular plants collections.

I think that Holger has certainly been the most enthusiastic about his finds with new records not just for Costa Rica but the whole of Tropical America. We are quietly confident of having collected some new species but will need to wait until we get back to a herbarium to be sure. This highlights the importance of global reference collections, such as our own, to identifying new species.

Jo with the bulk of our collections, bagged up and ready to be transported
to the INBio herbarium for drying, sorting and identification

Well no valentine’s day cards…sniff. Tom from Nature Live has been showing off his card for the last week and I was tempted to write one for myself. Today was another beautiful day though; bright blue skies and a light breeze.

After having separated into two groups for the past three days it felt good for us all to be working together again. We walked along the river on a very accident-inducing, slippery trail, with stunning views every few minutes.

(Click images to see them full size)

Our site for the day was an area of ‘turbera’ or peat bog - an open expanse of lichen dominated ground with scattered tree ferns (Blechnum buchtienii) around whose base are even more lichens, epiphytes and shrubs.

Overlooking the bog was a loan, probably a dead oak tree, which despite having died is home to a mini forest of it’s own on each branch. I spent more time than I should have trying to work out how many species were in the tree and the logistics of climbing up to collect them.

It was hard work pressing in the bright sun but we collected 58 species of vascular plants and Holger and Jo made some more fantastic aquatic lichen and moss discoveries.

It makes a real difference having the perspective of a different group of organisms. Holger was able to identify substantial amounts of basalt rock in the river bed which helps keep the pH close to neutral and so favour a rich and perse lichen community. This also gives us some clues to the history of these mountains.

He also very conveniently measures the temperature of the river (12°C) which encouraged me to have a quick dip before we headed back to camp.