Dataset Information

A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities.

ABSTRACT: Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richness for clonal species was much higher than that of other breeding systems. A close linear relationship between traditional variety richness and evenness (both transformed), empirically derived from data spanning a wide range of crops and countries, was found both at household and community levels. Fitting a neutral "function" to traditional variety diversity relationships, comparable to a species abundance distribution of "neutral ecology," provided a benchmark to assess the standing diversity on farm. In some cases, high dominance occurred, with much of the variety richness held at low frequencies. This suggested that diversity may be maintained as an insurance to meet future environmental changes or social and economic needs. In other cases, a more even frequency distribution of varieties was found, possibly implying that farmers are selecting varieties to service a diversity of current needs and purposes. Divergence estimates, measured as the proportion of community evenness displayed among farmers, underscore the importance of a large number of small farms adopting distinctly diverse varietal strategies as a major force that maintains crop genetic diversity on farm.

SUBMITTER: Jarvis DI

PROVIDER: S-EPMC2291090 | biostudies-other | 2008 Apr

REPOSITORIES: biostudies-other

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A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities.

Jarvis Devra I DI Brown Anthony H D AH Cuong Pham Hung PH Collado-Panduro Luis L Latournerie-Moreno Luis L Gyawali Sanjaya S Tanto Tesema T Sawadogo Mahamadou M Mar Istvan I Sadiki Mohammed M Hue Nguyen Thi-Ngoc NT Arias-Reyes Luis L Balma Didier D Bajracharya Jwala J Castillo Fernando F Rijal Deepak D Belqadi Loubna L Rana Ram R Saidi Seddik S Ouedraogo Jeremy J Zangre Roger R Rhrib Keltoum K Chavez Jose Luis JL Schoen Daniel D Sthapit Bhuwon B De Santis Paola P Fadda Carlo C Hodgkin Toby T

Proceedings of the National Academy of Sciences of the United States of America 20080324 14

Varietal data from 27 crop species from five continents were drawn together to determine overall trends in crop varietal diversity on farm. Measurements of richness, evenness, and divergence showed that considerable crop genetic diversity continues to be maintained on farm, in the form of traditional crop varieties. Major staples had higher richness and evenness than nonstaples. Variety richness for clonal species was much higher than that of other breeding systems. A close linear relationship b ...[more]

PMID: 18362337

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Project description:Agricultural intensification is a leading threat to bird conservation. Highly diversified farming systems that integrate livestock and crop production might promote a diversity of habitats useful to native birds foraging across otherwise-simplified landscapes. At the same time, these features might be attractive to nonnative birds linked to a broad range of disservices to both crop and livestock production. We evaluated the influence of crop-livestock integration on wild bird richness and density along a north-south transect spanning the U.S. West Coast. We surveyed birds on 52 farms that grew primarily mixed vegetables and fruits alone or integrated livestock into production. Crop-livestock systems harbored higher native bird density and richness relative to crop-only farms, a benefit more pronounced on farms embedded in nonnatural landscapes. Crop-livestock systems bolstered native insectivores linked to the suppression of agricultural pest insects but did not bolster native granivores that may be more likely to damage crops. Crop-livestock systems also significantly increased the density of nonnative birds, primarily European Starlings (Sturnus vulgaris) and House Sparrows (Passer domesticus) that may compete with native birds for resources. Models supported a small, positive correlation between nonnative density and overall native bird density as well as between nonnative density and native granivore density. Relative to crop-only farms, on average, crop-livestock systems exhibited 1.5 times higher patch richness, 2.4 times higher density of farm structures, 7.3 times smaller field sizes, 2.4 times greater integration of woody crops, and 5.3 times greater integration of pasture/hay habitat on farm. Wild birds may have responded to this habitat diversity and/or associated food resources. Individual farm factors had significantly lower predictive power than farming system alone (change in C statistic information criterion (?CIC) = 80.2), suggesting crop-livestock systems may impact wild birds through a suite of factors that change with system conversion. Collectively, our findings suggest that farms that integrate livestock and crop production can attract robust native bird communities, especially within landscapes devoted to intensified food production. However, additional work is needed to demonstrate persistent farm bird communities through time, ecophysiological benefits to birds foraging on these farms, and net effects of both native and nonnative wild birds in agroecosystems.

Dataset Information

A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities.

Publications

A global perspective of the richness and evenness of traditional crop-variety diversity maintained by farming communities.

Similar Datasets

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