Biodiversity effects on yield of unsown species invasion in a temperate forage system

Swedish University of Agricultural Sciences, Department of Crop Production Ecology, Box 7043, SE-750 07 Uppsala, Sweden.
Annals of Botany (Impact Factor: 3.65). 02/2009; 103(6):913-21. DOI: 10.1093/aob/mcp008
Source: PubMed


Current agricultural practices are based on growing monocultures or binary mixtures over large areas, with a resultant impoverishing effect on biodiversity at several trophic levels. The effects of increasing the biodiversity of a sward mixture on dry matter yield and unsown species invasion were studied.
A field experiment involving four grassland species [two grasses--perennial ryegrass (Lolium perenne) and cocksfoot (Dactylis glomerata)--and two legumes--red clover (Trifolium pratense) and white clover (Trifolium repens)], grown in monocultures and mixtures in accordance with a simplex design, was carried out. The legumes were included either as single varieties or as one of two broad genetic-base composites. The experiment was harvested three times a year over three years; dry matter yield and yield of unsown species were determined at each harvest. Yields of individual species and interactions between all species present were estimated through a statistical modelling approach.
Species diversity produced a strong positive yield effect that resulted in transgressive over-yielding in the second and third years. Using broad genetic-base composites of the legumes had a small impact on yield and species interactions. Invasion by unsown species was strongly reduced by species diversity, but species identity was also important. Cocksfoot and white clover (with the exception of one broad genetic-base composite) reduced invasion, while red clover was the most invaded species.
The results show that it is possible to increase, and stabilize, the yield of a grassland crop and reduce invasion by unsown species by increasing its species diversity.

Download full-text


Available from: B. E. Frankow-Lindberg,
  • Source
    • "Diversity-Interactions models (Kirwan et al. 2007, 2009) address many of the issues above within a single framework. They have been used in understanding the BEF relationship in a number of plant and invertebrate assemblages (Sheehan et al. 2006; Kirwan et al. 2007; Connolly et al. 2009, 2011; Frankow-Lindberg et al. 2009; Nyfeler et al. 2009; O'Hea, Kirwan & Finn 2010; Brophy et al. 2011). However, they do not fit all data adequately (Fig. 1a). "
    [Show abstract] [Hide abstract]
    ABSTRACT: * The development of models of the relationship between biodiversity and ecosystem function (BEF) has advanced rapidly over the last 20 years, incorporating insights gained through extensive experimental work. We propose Generalised Diversity-Interactions models that include many of the features of existing models and have several novel features. Generalised Diversity-Interactions models characterise the contribution of two species to ecosystem function as being proportional to the product of their relative abundances raised to the power of a coefficient θ. * A value of θ < 1 corresponds to a stronger than expected contribution of species' pairs to ecosystem functioning, particularly at low relative abundance of species. * Varying the value of θ has profound consequences for community-level properties of BEF relationships, including: (i) saturation properties of the BEF relationship; (ii) the stability of ecosystem function across communities; (iii) the likelihood of transgressive overyielding. * For low values of θ, loss of species can have a much greater impact on ecosystem functioning than loss of community evenness. * Generalised Diversity-Interactions models serve to unify the modelling of BEF relationships as they include several other current models as special cases. * Generalised Diversity-Interactions models were applied to seven data sets and three functions: total biomass (five grassland experiments), community respiration (one bacterial experiment) and nitrate leaching (one earthworm experiment). They described all the nonrandom structure in the data in six experiments, and most of it in the seventh experiment and so fit as well or better than competing BEF models for these data. They were significantly better than Diversity-Interactions models in five experiments. * Synthesis. We show that Generalized Diversity-Interactions models quantitatively integrate several methods that separately address effects of species richness, evenness and composition on ecosystem function. They describe empirical data at least as well as alternative models and improve the ability to quantitatively test among several theoretical and practical hypotheses about the effects of biodiversity levels on ecosystem function. They improve our understanding of important aspects of the relationship between biodiversity (evenness and richness) and ecosystem function (BEF), which include saturation, effects of species loss, the stability of ecosystem function and the incidence of transgressive overyielding.
    Journal of Ecology 03/2013; 101:344-355. DOI:10.1111/1365-2745.12052 · 5.52 Impact Factor
  • Source
    • "Altering the composition of forage mixtures did not affect dry matter intake, milk production or blood metabolite profiles of lactating Holstein cows (Soder et al., 2006). Functional diversity enhanced the resistance of temperate grasslands to weed invasion in both extensively and intensively managed swards (Frankow-Lindberg et al., 2009). Including forages in the crop rotation also led to higher yields in the grain crops planted after the forage, because of less soil disturbance, increased soil organic matter and weed control (Gliessman, 2006). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Agroecology and industrial ecology can be viewed as complementary means for reducing the environmental footprint of animal farming systems: agroecology mainly by stimulating natural processes to reduce inputs, and industrial ecology by closing system loops, thereby reducing demand for raw materials, lowering pollution and saving on waste treatment. Surprisingly, animal farming systems have so far been ignored in most agroecological thinking. On the basis of a study by Altieri, who identified the key ecological processes to be optimized, we propose five principles for the design of sustainable animal production systems: (i) adopting management practices aiming to improve animal health, (ii) decreasing the inputs needed for production, (iii) decreasing pollution by optimizing the metabolic functioning of farming systems, (iv) enhancing diversity within animal production systems to strengthen their resilience and (v) preserving biological diversity in agroecosystems by adapting management practices. We then discuss how these different principles combine to generate environmental, social and economic performance in six animal production systems (ruminants, pigs, rabbits and aquaculture) covering a long gradient of intensification. The two principles concerning economy of inputs and reduction of pollution emerged in nearly all the case studies, a finding that can be explained by the economic and regulatory constraints affecting animal production. Integrated management of animal health was seldom mobilized, as alternatives to chemical drugs have only recently been investigated, and the results are not yet transferable to farming practices. A number of ecological functions and ecosystem services (recycling of nutrients, forage yield, pollination, resistance to weed invasion, etc.) are closely linked to biodiversity, and their persistence depends largely on maintaining biological diversity in agroecosystems. We conclude that the development of such ecology-based alternatives for animal production implies changes in the positions adopted by technicians and extension services, researchers and policymakers. Animal production systems should not only be considered holistically, but also in the diversity of their local and regional conditions. The ability of farmers to make their own decisions on the basis of the close monitoring of system performance is most important to ensure system sustainability.
    animal 12/2012; 7(6):1-16. DOI:10.1017/S1751731112002418 · 1.84 Impact Factor
  • Source
    • "It was based on a common experiment using four-species mixtures and monocultures of forage legumes and grasses repeated at a number of sites across Europe and in Canada and Australia (Kirwan et al., 2007). The COST 852 experiment included an optional treatment in which the impact of the level of intraspecific variation in the legume species (red clover and white clover) was assessed by the use of single varieties vs. wide genetic base (WGB) composites, comprising mechanical seed mixtures of many varieties and populations (Collins et al., 2004; Frankow-Lindberg et al., 2009). The WGB populations were developed with the intention of testing the effect of increased phenotypic diversity on the agronomic performance of important forage legumes. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Backgound and Aims Extending the cultivation of forage legume species into regions where they are close to the margin of their natural distribution requires knowledge of population responses to environmental stresses. This study was conducted at three north European sites (Iceland, Sweden and the UK) using AFLP markers to analyse changes in genetic structure over time in two population types of red and white clover (Trifolium pratense and T. repens, respectively): (1) standard commercial varieties; (2) wide genetic base (WGB) composite populations constructed from many commercial varieties plus unselected material obtained from germplasm collections. Methods At each site populations were grown in field plots, then randomly sampled after 3?5 years to obtain survivor populations. AFLP markers were used to calculate genetic differentiation within and between original and survivor populations. Key Results No consistent changes in average genetic diversity were observed between original and survivor populations. In both species the original varieties were always genetically distinct from each other. Significant genetic shift was observed in the white clover ?Ramona? grown in Sweden. The WGB original populations were more genetically similar. However, genetic differentiation occurred between original and survivor WGB germplasm in both species, particularly in Sweden. Regression of climatic data with genetic differentiation showed that low autumn temperature was the best predictor. Within the set of cold sites the highest level of genetic shift in populations was observed in Sweden. Conclusions The results suggest that changes in population structure can occur within a short time span in forage legumes, resulting in the rapid formation of distinct survivor populations in environmentally challenging sites.
    Annals of Botany 03/2012; 110(6):1341-50. DOI:10.1093/aob/mcs058 · 3.65 Impact Factor
Show more