Agricultural intensification : saving space for wildlife?

Key words: agricultural frontier; smallholder; intensification; semi-arid area; wildlife; conservation agriculture; cotton; Zimbabwe. Increasing agricultural production and preventing further losses in biodiversity are both legitimate objectives, but they compete strongly in the developing world. In this study, current tensions between agricultural production and environmental conservation were described and analysed in Mbire District, an agricultural frontier shared with wildlife that lies in the Mid-Zambezi Valley, in the northern fringe of Zimbabwe. The potential of conservation agriculture (CA) to intensify agricultural production with minimum negative environmental effects was then explored. The population of Mbire District almost doubled between 1992 and 2002, while the livestock densities increased at rates above 15% in the early 1990s and the late 2000s. From 1980 to 2007, the expansion of farmland over the years was described by an exponential relationship. It was suggested that these changes affected elephant and buffalo numbers negatively. Increase in human population, increase in cattle population, and expansion of cotton farming were all drivers on the observed land use change. However, cotton farming was demonstrated to be paramount, enabling cattle accumulation and expansion of plough-based agriculture. The ‘environmental footprint’ per farm was increasing significantly with the area under cotton and with the number of draught animals owned. A kilogram of seed cotton required 50% more land, removed twice as much N, 50% more K and 20% more P than a kilogram of cereal. However, except for pesticide, one man-day invested in cotton production had a smaller environmental footprint than a man-day invested in cereal production. As farming in Mbire District is limited by labour more than by land, specialising in cereal production would increase the total area occupied by crops and fallows, whilst specializing in cotton production would reduce this area. Therefore, maintaining or increasing the relative profitability of cotton vs. cereal may ‘spare land’ for nature. Compared with current farmers’ cropping practices (CP), CA had no effect on cotton productivity during years that received average or above average rainfall. During a drier year, however, CA was found to have a slightly negative effect (110 kg ha-1 less in on-farm trials and 220 kg ha-1 less in farmers’ cotton fields). Most soils in the study area are coarse-textured soils, on which runoff were significantly greater with CA than with CP. For these reasons, farmers perceived ploughing as necessary during drier years to maximize water infiltration, but saw CA as beneficial during wetter years as a means to ‘shed water’ and avoid waterlogging. In Zimbabwe, the approach used in the extension of CA appears to differ little from an earlier attempt to intensify smallholder agricultural production almost a century earlier: the Alvord model. In particular, the rationale of African smallholder farming has been persistently ignored. The analysis of smallholder farming practices in Mbire District showed how the socio-economic constraints they faced predisposed them towards extensification. In particular, labour availability for weeding was found to be a major limiting factor in the area. The increased weed pressure in CA is therefore a major reason preventing smallholders from embracing it. As a conclusion, mitigating conflicts between agricultural production and biodiversity conservation will require major innovations, far beyond CA. CA should be seen as part of a larger basket of technologies aiming at ‘ecological intensification’. In parallel to the development of technical innovations, local institutions should be empowered and strong regulations put in place. </p

Warming temperatures and smaller body sizes : synchronous changes in growth of North Sea fishes

Funded by Marine Scotland SciencePeer reviewedPostprin

Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

We present a parareal in time algorithm for the simulation of neutron diffusion transient model. The method is made efficient by means of a coarse solver defined with large time steps and steady control rods model. Using finite element for the space discretization, our implementation provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch-Maurer-Werner (LMW) benchmark [1]

EVALUATING THE RELATIVE CONTRIBUTION OF CHANGING FARMING METHODS TO HABITAT LOSS IN THE MID-ZAMBEZI VALLEY, ZIMBABWE

Agriculture expansion is a major contributor to wildlife habitat loss in the ecological frontier areas. However, little is known about the contribution of different crops to wildlife habitat loss. In this study we evaluated the relative contribution of changes in farming practices, particularly the introduction of cotton (Gossypium hirsutum L) to the loss of wildlife habitat with specific focus on the African elephant (Loxodonta africana) in the mid- Zambezi Valley, Zimbabwe. First, we developed a remote sensing method based on normalised difference vegetation index (NDVI) derived from 16 day multi-temporal Moderate Resolution Imaging Spectroradiometer (MODIS) remotely sensed data for the 2007 growing period, to test whether cotton (Gossypium hirsutum L) fields can significantly (p < 0.05) be distinguished from maize (Zea mays L) fields, as well as sorghum (Sorghum bicolor) fields. Second, we tested whether woodland fragmentation in the study area was best explained by the areal extent of cotton fields than the areal extent of cereal fields. Finally, we tested whether woodland fragmentation resulting from cotton fields explains elephant distribution better than woodland fragmentation resulting from the extent of cereal fields. Results show that multi-temporal remotely sensed data can be used to distinguish and map cotton and cereal fields. Cotton fields contributed more to woodland fragmentation than cereal fields. Also, we found out that woodland fragmentation from cotton fields significantly explained elephant distribution in the mid- Zambezi Valley. These results indicate that the areal extent of cotton fields explains elephant habitat fragmentation more than the areal extent of cereal fields. Thus, we conclude that the expansion of cotton fields contributes most to elephant habitat loss in the Mid-Zambezi Valley. These results imply that elephant conservation policy needs to address the reduction of the negative impact of cash crops such as cotton on the habitat particularly their threat to wildlife habitat which may eventually lead to loss these wild animals. Thus it is important to strike a balance between wildlife habitat conservation and agricultural production as advocated through the Communal Areas Management Programme For Indigenous Resources (CAMPFIRE) polic

Impact of ocean warming on sustainable fisheries management informs the Ecosystem Approach to Fisheries

Acknowledgements Serpetti N., Heymans J.J., and Burrows M.T. were funded by the Natural Environment Research Council and Department for Environment, Food and Rural Affairs under the Marine Ecosystems Research Programme (MERP) (grant No. NE/L003279/1). Baudron A. and Fernandes, P.G. were founded by Horizon 2020 European research projects MareFrame (grant No. 613571) and ClimeFish (grant No. 677039). Payne, B.L. was founded by the Natural Environment Research Council and Department for Environment under the ‘Velocity of Climate Change’ (grant No. NE/J024082/1).Peer reviewedPublisher PD

Bigger juveniles and smaller adults : changes in fish size correlate with warming seas

Funding Information Niger Delta Development Commission (NDDC) H2020 Societal Challenges. Grant Number: 677039 ACKNOWLEDGEMENTS We thank Marine Scotland Science for their help during data compilation, notably for the West of Scotland. We are also grateful to Tara Marshall and John Morrongiello for their suggestions during early stages of data analyses. Funding for I.E.I. PhD comes from the Niger Delta Development Commission (NDDC), which is gratefully acknowledged. P.G.F., A.R.B. and A.P. were supported by the Horizon 2020 European research project ClimeFish (grant No. 677039).Peer reviewedPostprin