Ecological convergence of secondary phytochemicals along elevational gradients
NEW PHYTOLOGIST
Authors: Bakhtiari, Moe; Glauser, Gaetan; Defossez, Emmanuel; Rasmann, Sergio
Abstract
Biologists still strive to identify the ecological and evolutionary drivers of phytochemical variation that mediate biotic interactions. We hypothesized that plant species growing at sites characterized by high herbivore pressure would converge to produce highly toxic blends of secondary metabolites, independent of phylogenetic constraints. To address the role of shared evolutionary history and ecological niches in driving variation in plant phytochemistry, we combined targeted metabolomics with insect herbivore bioassays and with a set of growth-related traits of several Cardamine species growing along the entire elevational gradient of the Alps. We observed that Cardamine phytochemical profiles grouped according to previously established growth form categorizations within specific abiotic conditions, independently of phylogenetic relationship. We also showed that novel indices summarizing functional phytochemical diversity better explain plant resistance against chewing and sap-feeding herbivores than classic diversity indices. We conclude that multiple functional axes of phytochemical diversity should be integrated with the functional axis of plant growth forms to study phenotypic convergence along large-scale ecological gradients.
Inter-rater reliability of welfare outcome assessment by an expert and farmers of South Tyrolean dairy farming
ITALIAN JOURNAL OF ANIMAL SCIENCE
Authors: Katzenberger, Katja; Rauch, Elke; Erhard, Michael; Reese, Sven; Gauly, Matthias
Abstract
The implementation of an animal welfare assurance programme for dairy cattle in South Tyrol (Eastern Italian Alps) faces particular feasibility constraints due to the outstanding volume of travel associated with routine on-farm audits of remote mountain farms. Therefore, this study aims to estimate the inter-rater reliability of the expert's and farmers' welfare outcome assessment regarding recommendations to involve milk producers in animal welfare assurance within South Tyrolean dairy farming. A formal training programme containing a classroom session and an on-farm observation became mandatory for all 188 participating farmers, which was offered by the expert, applied as reference standard. On-farm data collected on the farmers' cows (data set of 1719 dairy cows) were compared at animal level. Cohen's kappa, respectively, weighted kappa, examined for several welfare indicators, range from slight to moderate agreement (kappa = 0.018 - 0.416; kappa(omega)= 0.163 - 0.310). These findings are further confirmed by results at farm level (ICC = 0.018 - 0.577). Continuous repeatability checks as part of routine audits are therefore proposed to substantially reduce the variability between the raters and to avoid significant bias in the welfare outcome assessment. In this way, the competence for regular and standardised monitoring could be increasingly transferred to dairy farmers in order to reduce the need for costly and time-consuming inspections by external auditors, which are in long-term perspective also harmful to the alpine environment. Additionally, the promotion of welfare assessment as an instructive management tool would intensify farmers' commitment to the assessment process.