Rodolphe Sabatier

Action versus Result-Oriented Schemes in a Grassland Agroecosystem: A Dynamic Modelling Approach

Effects of agri-environment schemes (AES) on biodiversity remain controversial. While most AES are action-oriented, result-oriented and habitat-oriented schemes have recently been proposed as a solution to improve AES efficiency. The objective of this study was to compare action-oriented, habitat-oriented and result-oriented schemes in terms of ecological and productive performance as well as in terms of management flexibility. We developed a dynamic modelling approach based on the viable control framework to carry out a long term assessment of the three schemes in a grassland agroecosystem. The model explicitly links grazed grassland dynamics to bird population dynamics. It is applied to lapwing conservation in wet grasslands in France. We ran the model to assess the three AES scenarios. The model revealed the grazing strategies respecting ecological and productive constraints specific to each scheme. Grazing strategies were assessed by both their ecological and productive performance. The viable control approach made it possible to obtain the whole set of viable grazing strategies and therefore to quantify the management flexibility of the grassland agroecosystem. Our results showed that habitat and result-oriented scenarios led to much higher ecological performance than the action-oriented one. Differences in both ecological and productive performance between the habitat and result-oriented scenarios were limited. Flexibility of the grassland agroecosystem in the result-oriented scenario was much higher than in that of habitat-oriented scenario. Our model confirms the higher flexibility as well as the better ecological and productive performance of result-oriented schemes. A larger use of result-oriented schemes in conservation may also allow farmers to adapt their management to local conditions and to climatic variations.

Robustness and management adaptability in tropical rangelands: a viability-based assessment under the non-equilibrium paradigm

Rangelands provide the main forage resource for livestock in many parts of the world, but maintaining long-term productivity and providing sufficient income for the rancher remains a challenge. One key issue is to maintain the rangeland in conditions where the rancher has the greatest possibility to adapt his/her management choices to a highly fluctuating and uncertain environment. In this study, we address management robustness and adaptability, which increase the resilience of a rangeland. After reviewing how the concept of resilience evolved in parallel to modelling views on rangelands, we present a dynamic model of rangelands to which we applied the mathematical framework of viability theory to quantify the management adaptability of the system in a stochastic environment. This quantification is based on an index that combines the robustness of the system to rainfall variability and the ability of the rancher to adjust his/her management through time. We evaluated the adaptability for four possible scenarios combining two rainfall regimes (high or low) with two herding strategies (grazers only or mixed herd). Results show that pure grazing is viable only for high-rainfall regimes, and that the use of mixed-feeder herds increases the adaptability of the management. The management is the most adaptive with mixed herds and in rangelands composed of an intermediate density of trees and grasses. In such situations, grass provides high quantities of biomass and woody plants ensure robustness to droughts. Beyond the implications for management, our results illustrate the relevance of viability theory for addressing the issue of robustness and adaptability in non-equilibrium environments.

Production and Robustness of a Cacao Agroecosystem: Effects of Two Contrasting Types of Management Strategies

Ecological intensification, i.e. relying on ecological processes to replace chemical inputs, is often presented as the ideal alternative to conventional farming based on an intensive use of chemicals. It is said to both maintain high yield and provide more robustness to the agroecosystem. However few studies compared the two types of management with respect to their consequences for production and robustness toward perturbation. In this study our aim is to assess productive performance and robustness toward diverse perturbations of a Cacao agroecosystem managed with two contrasting groups of strategies: one group of strategies relying on a high level of pesticides and a second relying on low levels of pesticides. We conducted this study using a dynamical model of a Cacao agroecosystem that includes Cacao production dynamics, and dynamics of three insects: a pest (the Cacao Pod Borer, Conopomorpha cramerella) and two characteristic but unspecified beneficial insects (a pollinator of Cacao and a parasitoid of the Cacao Pod Borer). Our results showed two opposite behaviors of the Cacao agroecosystem depending on its management, i.e. an agroecosystem relying on a high input of pesticides and showing low ecosystem functioning and an agroecosystem with low inputs, relying on a high functioning of the ecosystem. From the production point of view, no type of management clearly outclassed the other and their ranking depended on the type of pesticide used. From the robustness point of view, the two types of managements performed differently when subjected to different types of perturbations. Ecologically intensive systems were more robust to pest outbreaks and perturbations related to pesticide characteristics while chemically intensive systems were more robust to Cacao production and management-related perturbation.

Towards biodiversity-based livestock systems: review of evidence and options for improvement

A major challenge for livestock farming systems (LFSs) is to reconcile production with the management of natural resources, especially biodiversity and ecosystem services. Based on a review of research conducted on grassland- and rangeland-based LFSs, this paper addresses this challenge by analysing biodiversity as a product of and a key resource for LFSs. Although most studies reveal antagonisms between biodiversity and production, our findings show that it is possible to move towards synergies. The literature review sheds light on five points: (i) moving beyond an antagonistic view of biodiversity and production by considering biodiversity as a resource requires new criteria for biodiversity categorization from a taxonomic view to a functional one; (ii) functional biodiversity (both domestic and wild) considered as a resource provides beneficial properties (e.g. stability and resilience) to LFSs; (iii) links between production and biodiversity cannot be simply summarized as having a negative impact of production intensity as management practices have various impacts on the different components of biodiversity; (iv) impact assessment studies linking management of LFSs and biodiversity reveal complex multi-level interactions between grassland or rangeland management and biodiversity; (v) a large range of management options are available to move towards biodiversitybased LFSs. We conclude that future research should address the challenge of collective management of wild biodiversity at higher levels of organization (landscapes, territories, etc.) and that such collective management would greatly benefit from the experience of domestic biodiversity.

Trade-offs between pasture production and farmland bird conservation: exploration of options using a dynamic farm model

In European grassland landscapes, grazing and mowing play a key role for the maintenance of high-quality habitats that host important bird populations. As grasslands are also key resources for cattle feeding, there is a need to develop management strategies that achieve the double objective of production and biodiversity conservation. The objective of this study was to use a modelling approach to generate recognisable patterns of bird dynamics in farms composed of different land use proportions, and to compare their production and ecological dimensions. We developed a dynamic model, which linked grassland management to bird population dynamics at the field and farm levels. The model was parameterised for two types of suckling farms corresponding to contrasting levels of grassland intensification and for two bird species of high conservation value. A viability algorithm was used to define and assess viable management strategies for production and ecological performance so as to draw the shape of the relationship between both types of performances for the two types of farms. Our results indicated that, at the farm level, there was a farming system effect with a negative and non-linear relationship linking performance. Improving bird population maintenance was less costly in extensive farms compared with intensive farms. At the field level, the model predicted the timing and intensity of land use, maximising either production or ecological performance. The results suggested that multi-objective grassland management would benefit from public policies that consider levels of organisation higher than the field level, such as the farm or the landscape.

Effect of cattle trampling on ground nesting birds on pastures: an experiment with artificial nests

Abstract 1. In semi-natural grasslands, nest trampling by cattle can have a strong effect on hatching success but the relationship linking cattle density, incubation time and nest survival has for now only been hypothesized. 2. Based on an experiment with artificial nests, the objective of this study was to test the theoretical model generally used to estimate nest survival. In spring 2009, we conducted a one-month experiment on permanent grasslands of the French western marshlands grazed at three different stocking rates (1 LU.ha-1, 2 LU.ha-1 and 4 LU.ha-1). 3. The results confirmed that trampling depended on stocking rates. 4. Trampling had a major effect on nest survival (32-85% of nests destroyed). 5. The theoretical model classically used by managers and modellers proved to be a good approximation of the dynamics of nest trampling. 6. Synthesis and applications: We conclude that nest trampling has a major impact on nest survival in pastures and that the use of such a model could help managers to define acceptable levels of cattle densities.

Multi-scale trade-offs between production and environment in grassland agroecosystems: application to livestock farming systems and biodiversity conservation

Bearing in mind the objectives of this study to investigate the Barbary sheep fertility under our climatic conditions and to evaluate the efficiency of the prostaglandin f2α(pgf2α)injections in induction of fertile estrus in different seasons. For these objectives, some experiments were performed during the period from July,2008 to March, 2009. A total number of 300 Libyan Barbary ewes(3-6 years old, weighing 40-60 kg) was used in this experiment. Ewes were kept in privet farms, fed and managed similarly. Ewes were divided to four season groups(summer, autumn, winter and spring groups). Each season group was divided into treated and control. Animals in the treated groups were injected with double injections of 125 μg of prostaglandin f2α intramuscularly(i/m), 11 days apart. While those in control groups were injected with two injections of 1.0 ml of 0.9% NACL saline solution simultaneously with the treated ewes. At the same day (day 11) rams wearing painted sponges on their briskets regions were introduced for natural mating. Treated groups showed shorter estrus response time than control groups in all seasons(P<0.05). Estrus duration was longer in winter and spring than in summer and autumn (P<0.001),but no difference was found between treated and control groups inside seasons. Treated group showed higher pregnancy rate(P<0.001) in winter season than control group. Percentage of ewes lambed in winter was significantly high (P<0.001) among treated ewes than control (80 vs 38%). Lambing rate differed significantly (P<0.001) among treated groups in all seasons. Data were collected and calculated statistically using SPSS system for percentages, means, standard deviation(mean ± sd) analysis of variance (anova), Chi square and Dunacan’s test were used accordingly. Other values were measured, calculated and analyzed similarly. Adoption of technology in sheep farms of La Mancha, Spain J. Rivas1, C. De Pablos2, J. Perea1, C. Barba1, R. Dios-Palomares1, M. Morantes1 and A. García1 1Universidad de Córdoba, Campus Rabanales, 14014, Córdoba, Spain, 2Universidad Rey Juan Carlos, Paseo de los Artilleros, 28034, Madrid, Spain; pa1gamaa@uco.es Recently in Spain the milk production coming from sheep farms shows higher degrees of specialization based on the adoption of technologies. The aim of this research is to examine the pattern of adoption of technologies in sheep farms of La Mancha. Based on previous researches, from 77 questions, only 38 questions were selected by using qualitative and participatory methods; the chosen variables were grouped into six technology packages (TP): management, feeding, animal health and milk quality, pasture and land use, equipment and facilities, and reproduction and breeding program. The survey was applied to a sample of 157 farms. Using descriptive statistics each TP was characterized and the pattern of adoption was determined. The average of technologies adopted was of 18.4±6.0 (48.3%). TP showing higher degrees of implementation are animal health and milk quality (67.8%), feeding (56.0%) and management (55.7%), but their adoption is not sequential or responds to independent events. This research facilitates the identification of a number of technologies that must be implemented from an organizational strategy point of view. Moreover, all technologies are seeking a dynamic balance system that allows firms migrate to more efficient processes without losing their main attributes. As a technological challenge, an andrologic evaluation of ram, gynecologic evaluation of ewes prior to mating, early detection of non-productive animals are proposed; and a better use of productive records for the decision-making; aspects are recommended. The results of this analysis will have an impact on future research that attempts to improve the use of subproducts, forage reserves and improved rangeland management and hygiene control system, taking the quality milk as an strategic asset, so further research is necessary to assess the impact of each technology on the operating of the mixed system in the Mancha region. Session 40 Poster 20 Session 40 Poster 19In Italy, as in other European countries, since 2005 a program of selection for scrapie resistance in sheep, based on the PRNP polymorphism, has been implemented with the aim of increasing ARR ‘resistant’ allele and eliminating VRQ ‘susceptible’ allele. In a small breed, the ARR-carriers may be more related to each other than ranndomly chosen animals; as a consequence, for an equal number of reproducers the effective size may be smaller than expected in a pure genetic drift condition (1). In the Sambucana sheep breed (reared in Piemonte region, north-west Italy) the ARR allele frequency was higher than in other breeds, like Biellese for example, before the selection plan started (2). On the other hand, due to the reduced number of animals (3500), this breed is considered at risk of extinction (Piemonte Regional Rural Development Plan for 2007-2013 period). The aim of the present investigation was to evalute the impact of scrapie resistance selection on genetic variation of the Sambucana. INTRODUCTIONCONCLUSIONS During the last decade there has been growing scientific interest in the use of genomic information as an additional tool in conventional dairy cows’ breeding schemes. It is now well established that dairy cows’ fertility has declined during the last decades and this may not be remedied only by improved management. Given that there is a substantial genetic background in this decline, emphasis should be placed in efforts to improve dairy cows’ fertility through genetic selection. Although there are substantial genetic effects that contribute to this infertility, little progress has been made on the identification of major genes affecting reproduction traits. There is an urgent need to identify the genetic factors responsible for the decline in fertility in cattle. The objective of this study was to investigate the association of two specific polymorphisms, the SNP12195 and SNP11646 polymorphisms of the Signal Transducer and Activator of Transcription 5A (STAT5A) and Fibroblast Growth Factor 2 (FGF2) genes respectively with fertility in cattle. These genes have been previously reported to be associated with in vitro fertilization and embryonic survival rate in cattle.In European grasslands, grazing and mowing regimes are major drivers of the maintenance of many wild species, either through direct or indirect effects. To date, both types of effects were studied separately, mainly at the field scale and with no quantification of performance. Objective of this study was to model the trade-offs between ecological and productive performance of a grassland agro-ecosystem at two nested scales i.e. field and farm scales. We developed a dynamic model linking grass dynamics controlled by grazing or mowing to stochastic population dynamics of two grassland bird species. Bird dynamics were driven by both direct and indirect effects of management. Viable control framework was used to predict productive and ecological performance. At field scale, results showed that the best ecological performance was obtained at intermediate levels of productive performance (60 to 108 grazing days /ha /year). Above 108 grazing days, no grazing strategy was viable for either species due to the negative direct effects of management. Between 108 and 240 grazing days, the ecological-productive relationship showed a concave Pareto like frontier. Any improvement in productive performance entailed a strong decrease in ecological performance. As expected, at farm scale the best ecological performance was obtained with extensive farms. However, the ecological-productive relationship showed a convex Pareto like frontier indicating the occurrence of compensations among management regimes. In intensive farms, it was necessary to allocate 40% of farm area in low-intensity grazing in order to compensate for the negative effects of mowing and high-intensity grazing on birds. However this land allocation involved a 25% reduction in productive performance. Finally, we explore several forms of complementarities among farm types to improve overall performance.