Author: Luigi Guarino

Posted on

Diversity at your service

More from a participant at the 6th Henry A. Wallace/CATIE Inter-American Scientific Conference on “Agrobiodiversity in Mesoamerica — From Genes to Landscapes” at CATIE in Costa Rica.

The ecologists at the Wallace Symposium today waded deeply into the functional role of diversity in agricultural systems. How much diversity do we need in order to get the full benefit of ecosystem services? Is some diversity redundant? What is the trade-off between a world of all things bright and beautiful and one of increased yields, healthy children and growing economies?

Prof. Teja Tscharntke of the Georg-August University in Göttingen presented numerous studies to illustrate the importance of at least a certain amount of wild biodiversity within or in close proximity to agricultural systems. In Andean potato systems, simpler landscapes, lacking heterogeneity in natural habitats, led to higher levels of the pestilential tuber moth and reduction in yields. Coffee systems in Indonesia near natural forest had higher bee species diversity and higher levels of seed set. Hand pollination of cacao had remarkably higher impacts on yields compared to the effects of other major variables, indicating the supreme importance of the near invisible midges that pollinate one of the most revered crops in the world.

But just how much of this wild biodiversity we need, and in what form, are just two of the many questions that are being posed. Teja brought up the SLOSS debate, dating back to the 1970s, of whether single, large or several small reserves will conserve more biodiversity. His findings suggest that many small habitats capture more heterogeneity. Fabrice DeClerck was back with a study of the relationship between species richness and function, using food crops as a model. In a study of households in Sauri in Kenya, he categorized food crops according to the nutrient services they provided — whether high in carbohydrates or proteins or specific vitamins, etc. Not surprisingly, functional richness (i.e. provision of all the major nutrients) was not necessarily associated with the highest species richness. You don’t have to grow everything to get your daily needs of protein and carbs, and for some nutrients (e.g. vitamin C) there is more species redundancy than others (e.g. folates). Well, I guess you had to be there!

The functional role of agrobiodiversity changes as you move from species to landscapes, and few principles can be transported across scales or systems. But that doesn’t stop a little healthy application of diversity when it’s needed. There was a nice case study of the use of plant diversity in and around Costa Rican farms of Dracaena to reduce pest populations that were causing exports of the ornamental plants to be held up by the US quarantine service. Secondary forest or certain types of cover crop can host populations of natural predators to the cicadellid pests. Consequently, the healthy plants passed through quarantine without a hitch and increased Costa Rica’s export revenues.

Posted on

Prizes for agrobiodiversity movers and shakers

Two of the recipients of the 16th Heinz Awards for “providing solutions to global environmental challenges,” announced yesterday, have agricultural biodiversity connections. Cary Fowler’s work is of course well know to our readers:

At a time of massive environmental change, it is an absolute necessity to preserve the world’s crop biodiversity. Lack of crop diversity threatens the world’s basic food security, and it is highly significant that scientists like Dr. Fowler work to strengthen inventories of plant genetic resources.

Gretchen Daily’s perhaps less so.

Dr. Gretchen Daily is a globally renowned scientist and Stanford University professor who is acknowledged for her innovative work to calculate the financial benefits of preserving the environment. Dr. Daily has advanced a remarkable new vision that harmonizes conservation and human development. Her work illuminates the many valuable benefits that flow from “natural capital” – embodied in Earth’s lands, waters and biodiversity – to supporting human well-being.

Today she also won a Midori biodiversity prize.

Much of Daily’s research seeks to get businesses thinking about the environment. In 2004, she published a paper showing that coffee plants located near forests in Costa Rica are more productive than other plants because they are pollinated by bees living in the forest. The bees boost the yearly income of the average farm by $60,000, she estimated.

Maybe the two recipients should get together and figure out how to get business to pay for genebanks. Congratulations to both.

Posted on

Featured: Taro leaf blight in Cameroon

Zachee Ngoko confirms many experts’ worst fears about a new taro disease in Cameroon:

Our investigation, confirmed by CABI showed that P. colocassiae is the agent responsible in Cameroon from lab. analysis and rapid mount… But we are in the process of having more information on the situation with the help from CABI/Global Plant Clinic, UK. More information will come out as soon as available.

Posted on

From Genes to Landscapes in Mesoamerica

From a special correspondent at the 6th Henry A. Wallace/CATIE Inter-American Scientific Conference on “Agrobiodiversity in Mesoamerica — From Genes to Landscapes.” Taking place 20-24 September 2010, at CATIE, Turrialba, Costa Rica.

Four days packed with presentations and discussions on Agrobiodiversity in Mesoamerica. And what biodiversity! Beans, maize, coffee, cacao, peppers … there is little to match the domestication feats of Central America! As part of the backdrop to the meeting, hosted by CATIE in Costa Rica, the gently fuming Volcano Turrialba is a quiet reminder of the turbulent rise and fall of civilisations and the dynamism and resilience of their culture.

The dynamism of agricultural systems was a striking recurrent theme of the first day’s talks; a morning dedicated to agricultural landscapes and an afternoon on the agricultural diversity in the landscapes. The symposium organiser, Fabrice DeClerck of CATIE, gave an inspiring introduction to the meeting, insisting that biodiversity is no longer a luxury item on the world’s development agenda. No-one needs to persuade policy makers anymore that biodiversity is central to the achievement of the Millennium Development Goals — a point made by Peter Kareiva and Michelle Marvier in Conservation for the People.

The issue is not so much the importance of biodiversity anymore, but how to pin it down … or at least how to focus on the important parts. Chili peppers are not spicy because we like them that way. Or not only. The heat-inducing biochemicals make the chili seeds resistant to attack from fungi while maintaining their attractive appeal to bird dispersers. Human’s domestication and use of chili peppers as a major ingredient in indigenous cuisine the world over, of course, is a happy sideline to what is clearly the result of very dynamic ecosystem processes. So which bits to save?

Jeremy Haggar of CATIE illustrated further the amazing dynamism of agricultural systems. In a study of tree species in coffee agroforestry systems he inventoried 16 smallholder farms in Nicaragua. Among the 110 tree species he identified, farmers selected a small number of species (5 or 6) that they wished to remove from their farms in favour of more useful species. Three years later, returning to the same farms, he was surprised to find that more than 30 of 110 species had disappeared, but that some 30 species were also new to the farms. Natural processes of colonisation had been considerably more effective at changing species composition than the farmers!

Jeremy also rang alarm bells, repeated by a number of speakers, about another looming source of dynamism, climate change. There will be a 60% reduction in the area suitable for coffee cultivation in Central America by 2050, as these cultural systems are driven uphill. Systems may be dynamic but it is not clear how ultimately resilient they are.

From the species perspective, Xavier Scheldeman of Bioversity International and Daniel Debouck of CIAT both described loss of populations of unique crop diversity: Capsicum flexuosum, a rare chili wild relative, has disappeared from the few collecting sites from which it was known in Paraguay as soybean cultivation has taken over. Similarly, one of the few populations of a wild bean species in Costa Rica has been built over. New populations of C. flexuosum have, fortunately, been found using targeted, GIS-aided collecting. The bean is also, thankfully, safely secured in the Svalbard Global Seed Vault.

So far, no connection has been made between crop species or relatives with priority traits for conservation and the ecosystems or landscapes in which they may be conserved. Clearly, a little more joined up thinking is needed. Bringing together this mixed bunch of scientists is a good start, and at the end of the four days the intention is to develop a white paper to guide policy-makers on priorities for agrobiodiversity conservation in Mesoamerica. Stay tuned!

Posted on

On local greens and homegardens and local greens

ResearchBlogging.orgGreat to see two papers by our friends at Bioversity come out in rapid succession recently relating to two project with which I was marginally connected in their early stages back in the 90s. One is on African leafy vegetables (ALV) 1, a common subject here. And the other on homegardens 2.

The ALV paper tries to measure the impact of the work carried out starting in the mid-90s to identify and address key constraints to production and consumption. This is fairly easy to do in terms of research papers published and MSc degrees awarded, but more tricky when it comes to measuring what ALVs mean to the people who eat them. The authors tried to do this through fieldwork at four sites in Kenya. There’s no doubt there has been an increase in ALV production and marketing during the past 10 years, and a significant change in perceptions about these species, which are no longer considered simply “food for the poor.” Their presence in upmarket Nairobi supermarkets is testament to that. What still needs to be verified is that this is leading to significant nutrition and health benefits.

A particularly poignant aspect of this study was the way it highlighted the importance of one person, the late Prof. James Chewya of the University of Nairobi, in driving the early ALV work, in particular by influencing young researchers to get involved. Jim is still much missed.

The homegardens paper is less specifically tied in to the Bioversity project on this topic which began in the early 90s, being essentially a review of the literature of the past couple of decades. 3 It rehearses the biological features of homegardens, in particular their complexity and diversity, stresses their cultural and socio-economic importance, and describes how these drive each other. The section on the future of homegardens as loci for research and conservation is especially interesting in its juxtaposition of the somewhat different roles of these intensive micro-environments in developing and high-income countries. 4

In developing countries, the nutritional value of local, neglected horticultural species has been assessed and their cultivation in family gardens promoted to guarantee the intake of vitamins and micro-nutrients aiding in the control of HIV infections and other diseases. Establishment of food producing gardens, often based on local seed systems and traditional crops, in areas of explosive urbanization is becoming an important tool for making cities more sustainable while also providing marginal sectors of the population with working opportunities, healthier food and reinforcing their cultural identity.

Well, couldn’t you say much the same of the situation in the US and Europe?

In high-income countries the growing demand for healthier lifestyles and closer connection with nature has driven a renewed interest towards sustainable agricultural systems and ‘‘traditional’’ food products, capable of connecting consumers to the natural and cultural heritage of a community or a geographical region.

True enough, but the ALV experience in Kenya shows that this trend is not confined to places where Slow Food is active. Surely there is more scope for mutual learning.

If there’s one thing that disappointed me a little in reading through these two papers is the seeming lack of cross-fertilization between them. ALV are increasingly common in urban homegardens in Kenya. It would have been nice to see the lessons learned in the course of these two major projects brought together somehow. Maybe something along those lines is in the offing. I hope so. But that is to quibble. It is wonderful to see undervalued species, and the overlooked micro-environments where they often grow, coming into their own.