In Boubourkabé village we got the chance to visit harvested millet fields and granaries built in these fields to store millet and sorghum grains (Fig. 2). The granaries are made up of wooden sticks and grass, clearly far from being rodent-proof storage. We noticed signs of rodent activity inside and outside the granaries (Fig. 3). In fact, unprotected granaries placed in the middle of the fields amount to ‘a feast for the rodents.’ There is always ample food either in the field or in the granary. If the rodents cannot feed on the standing crop, they can survive and thrive in the grain storage placed in the middle of the fields. Inside houses, grains are stored mainly in polyethylene bags which are economically affordable but highly susceptible to rodent attack. In terms of rodent management locally, unfortunately, nothing is happening, except that some farmers rely on anticoagulant rodenticides purchased from the local markets. Alternative rodent management methods are not available.
There is still much unknown. Empirical data on field and storage losses to rodents is lacking in Niger. It would be useful to fill these knowledge gaps and have an inventory of local rodent management practices. It is also important and urgent to test a number of tailored ecologically based rodent management actions.
The grain storages are now at the heart of the rodent damage. We believe that cereal farmers in Niger are losing significant quantity of their grains to rodents by storing in polyethylene bags and granaries which have proven time and again to be ineffective against rodents and make it possible for rodents to sustain their population throughout the year. Therefore, it is necessary to innovate, adapt / adopt better grain storage materials, such as hermetic bags, metallic silos, and rodent-proof granaries to reduce the impacts of grain attack by pest insects and rodents. We believe the practice of grain storage in the middle of the fields should change, in consultation with communities. We also recommend tests on the effectiveness of some hermetic bags against these pests in the Nigerien context (taking into account the weather, rodent species, and storage systems) and damage estimation to fill the knowledge gap.
We recommend an experimental trial that represents an urban situation. Gamkalleye, part of Niamey, would an ideal trial site. The target rodent species would be Rattus, Mastomys natalensis, Mus musculus, and Arvicanthis niloticus; and the target grain shall be rice and/or maize. For the rural trial, the setup in Boubourkabé village is ideal, as it has a mix of cropped fields, outdoor granaries, and rural settlements. Here the experimental grain could be millet and the target rodent species would be Mastomys erythroleucus, Rattus and Arvicanthis niloticus.
A range of EBRM (Ecologically Based Rodent Management) actions could be trialed around the granaries in Boubourkabé by setting up, for example, two independent locations (control and experimental) where rodents would be trapped on a monthly basis in the presence and absence of tailored EBRM actions. The actions may include community awareness campaigns, sustained community rodent management campaigns involving cleaning around granaries for rodent harbourage, sustained trapping (e.g., monthly trapping campaigns), destroying and flooding burrows, runways, attracting natural predators (e.g., installing raptor perches), installing movement interrupters (e.g., rodent baffles and collars on the pillars of the granaries), improving standard of granaries by adding rodent-proof materials at the base and sides of the granaries (e.g., corrugated iron sheet), and applying bio-rodenticides. Since the granaries are located in crop fields (not in homesteads), it is possible to spot taxa such as Gerbillus, Jaculus, and Taterilus around in addition to the storage rodent taxa mentioned above.
EBRM would also need to be introduced in urban and peri-urban settings and make it part of neighbourhood development. This is a new thing in Africa, and it is likely to pose a wide range of challenges not encountered in rural EBRM. This trial in Gamkalleye would be the first of its kind at least on the African continent. The EBRM actions which could be trialed here may include:
The recent visit of MetaMeta staff to Niger was financially supported by funds obtained from the French Institute of Research for Sustainable Development (IRD) and core funds of MetaMeta. We thank MetaMeta Research, Rodent Green Company, Abdou Moumouni University, and the Nigerien Ministry of Agriculture for permitting staff exchange and organizing local travels and activities in Niger.
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Recommended citation: Meheretu, Y., Hima, K., Garba, M., Bosma, L., Dobigny, G. (2021). Protecting the granary: the need for Ecologically Based Rodent Management in Sahelian Niger. MetaMeta Research and Rodent Green, Wageningen, The Netherlands. (https://thewaterchannel.tv/thewaterblog/protecting-the-granary-the-need-for-ecologically-based-rodent-management-in-sahelian-niger/)