Ecological network analysis to link interactions between system components and performances in multispecies livestock farms

Organic farming relies on ecological processes to replace chemical inputs, and organic farmers have developed various strategies, including several forms of diversification, to remain viable. Herein, we hypothesized that diversified organic farming systems can enhance their performance by increasing the level of interactions between system components. We therefore performed an ecological network analysis to characterize both within-farm and farm-environment interactions. Flows were expressed on an annual basis according to the quantity of biomass exchanges multiplied by nitrogen content. Seventeen organic farms were surveyed in French grassland areas, each associating beef cattle with either sheep, pigs, or poultry. The ecological network analysis was then coupled with the assessment of farm economic, environmental, and social performances. A hierarchical clustering on principal components distinguished five groups of farms based on farm and herd size, presence of monogastrics, percentage of crops in the farm area, and system activity indicators. A large farm size, in terms of area or number of workers, can limit the implementation of a homogeneous flow network within the system. A higher level of within-system interactions did not lead to better farm economic, environmental, and social performances. Systems with large monogastric production enterprises were highly dependent on inputs, which led to less homogeneous flow networks and a poor farm nitrogen balance without gaining economic efficiency. Managing a complex system with a dense and complex flow network did not appear to increase farmers’ mental workload. To our knowledge, this study is the first to quantify farm-scale interactions using ecological network indicators in temperate livestock farms and to analyze the links between farm performance and operating processes. The ecological network analysis thus potentially provides a common framework for comparing a wide range of livestock farms. Given the variability of multispecies livestock farms, a larger database will be used to extend our conclusions.