Gender, vegetable farming systems and diversity of vegetable species around agro-pastoral dams
Vegetable production around the APDs is less intensive and characterized by low use of external inputs and rudimentary or small-scale tools and equipment. Vegetable species are dominated by African indigenous species, and the use of improved seeds is low. It is a part-time activity for the majority of people involved and represents a typical example of traditional vegetable farming systems common in West Africa . Indeed, in traditional vegetable farming systems, vegetable production and marketing are undertaken mainly by women [2, 26, 27]. This is the case in Fombawi and Sakabansi, the rural areas, where this activity is undertaken exclusively by women. However, men become more involved as soon as income generation potential increases and the activity takes on a commercial orientation [27, 28]. This can explain why more men were involved in vegetable production and mainly cultivated species with high commercial or economic values in Nikki, the more urban area, with improved roads and market access.
Our results revealed that there was a strong gender difference in cropping systems and farming practices around the APDs investigated, except irrigation practices. These findings are consistent with previous studies on gender dimensions in agriculture in sub-Saharan Africa . The gendered difference observed in the cropping systems may be due to differences in access to land. In fact, men had larger plot sizes compared to women, as it was also reported in vegetable production systems in Buea, Cameroon  and in southwestern Nigeria . This supports the general gender-differentiated resource base of African farming systems [29, 31]. Thus, the fact that monocropping and intercropping were predominantly practised by women could be seen as a strategy to cope with the challenge of limited plot sizes to maximize the utilization of the small plot of land they have.
Like Reyes-García et al. , we found that men and women producers used different soil fertility, and pest and disease management practices. Organic fertilizers and traditional pest management practices were predominantly used by women. This may be due to difference in knowledge of farming practices and in access to information and the ability to act upon it [26, 31]. In fact, female farmers are less likely to access agricultural information and knowledge through extension services, or receive very limited access to quality services and agricultural technology information compared to their male counterparts [30, 33]. Differences in access to inputs may also play a role in the gendered nature of vegetable production around APDs [26, 29]. Indeed, chemical inputs used around the APDs are mainly those intended for cotton cultivation. In the study areas, only cotton farmers, who are exclusively men, can have access to those inputs. Furthermore, difference in access to labour can explain the gender difference in vegetable production systems around APDs. Indeed, because of the gender-differentiated nature of rural household labour shortages or the gendered nature of labour-hiring practices in African farming systems , women usually have less access to labour for labour-intensive farming activities.
Vegetable species cultivated around APDs were mainly leafy vegetables. Our findings also indicated that species cultivated were predominantly African indigenous vegetable species (63% of vegetables cultivated). This highlights the potential role of vegetable production around APDs towards improving food and nutritional security in the study area [3,4,5, 8, 34]. Indeed, proteins, carbohydrates, dietary fibres, potassium, calcium, magnesium, phosphorus, Vitamin A, Vitamin C and Vitamin E have been shown to be significantly higher in indigenous vegetables than their exotic counterparts . Our findings that women cultivated mainly traditional vegetables in comparison with men corroborates previous results by Ndenga et al.  that indicated women vegetable producers in the Rift Valley and Central provinces in Kenya allocated more land for the production of traditional vegetables than men.
Challenges to vegetable production around agro-pastoral dams
Some of the key challenges faced by vegetable producers around APDs, namely, lack of equipment, access to inputs and credit or capital, and access to and fluctuation of market opportunities are not specific to working around agro-pastoral dams. These constraints have been reported previously in vegetable production systems in Benin, Cameroon, Nigeria, Senegal and South Africa [8, 9, 26, 30, 37]. Although we did not assess how gender affects the perception of the constraints (e.g. Ngome and Foeken  and Alao et al. ), we found a strong and significant agreement on the ranking of the most important constraints among the respondents, indicating that gender did not considerably affect the perception of the constraints in our study. In addition, contrary to previous investigations in southern Benin and elsewhere in West Africa that reported access to land as a major constraint for vegetable production, especially in urban areas [9, 11, 12, 37, 38], we found that land access is not a major challenge for vegetable producers around APDs, even in the more urbanized study area. Indeed, challenges related to land access have been ranked as second to last (out of ten) around almost all the three APDs (see Table 2). This is inconsistent with results by Ogunjimi and Adekalu  and Cissé et al. , which reported strong competition over lands around the major perennial streams in Nigeria and around APDs in Ouagadougou, Burkina Faso, respectively.
However, conflicts with livestock keepers (due to recurrent destruction of vegetable plots and seedlings by livestock) were challenges specific to vegetable production around APDs, especially in the rural study areas. It is very likely to be the case around other APDs in northern Benin where vegetable production occurs. Indeed, the APDs were constructed initially to provide additional drinking water for livestock production after the severe drought experienced in Benin in the 1970s, which had seriously affected the national livestock population . Consequently, up to now, some livestock herders believe that the APDs are for them and they have more use-rights than other stakeholder groups, though there is a dam management committee (CoGes) for each APD [16, 17].
Another key challenge for producers around the APDs is access to water, especially at the peak of the dry season. This constraint has also been reported by small-scale irrigation farmers along major rivers in Nigeria . Unfortunately, since the majority of the producers are located upstream of the dams, the strategies they have developed to cope with this challenge, which include digging wells and boreholes in the dams’ watercourse, potentially contribute to dam siltation. In addition, with frequent tillage, soils become more vulnerable to erosion and easily transported into the waterholes by runoff . Some of the producers are perfectly aware of this since they have identified farming and vegetable production around the dams as causes of dam siltation in the study areas. However, very few respondents ranked vegetable production as the first cause of dam siltation, while more experienced producers around APDs and those with high vegetable species richness were more likely to rank farming as the first cause of dam siltation.
Although pest and disease management was reported to be a very key challenge for vegetable farmers in southern Benin and in other regions of Africa [41, 42], it was not perceived as a major constraint around APDs. It was only in urban Nikki that pest and disease pressures emerged as a serious constraint. This can be explained by the fact that urbanization process modifies farmer practices in response to increased food demand, changes dietary patterns towards fruits and vegetable consumption, and increases competitiveness of fruits and vegetable production in the urban and peri-urban areas over staple crops . Pest and disease pressures combined with the challenge of limited access to pesticides have led men producers in Nikki to have recourse to non-recommended pesticides (namely, those intended for cotton cultivation). This practice is not specific to vegetable production around APDs and has actually been reported in the fruit and vegetable production systems of small farmers in sub-Saharan Africa . This raises the issues of the quality of vegetables produced and the health risks not only for consumers and producers but also living organisms in the dams such as crocodiles and fishes [38, 41, 42]. Moreover, utilization of APD water can also represent significant health risks due to bacteriological and microbial contaminations [39, 43]. As explained by respondents, livestock defecate and urinate directly into the dams when drinking water, contributing to water contamination. In addition, given the inappropriate waste disposal and poor waste water management system, especially in the town of Nikki , it is very likely that runoffs, streams and effluents that feed the dams carry pathogens contaminating dam water .
Implications and research avenues for sustainable vegetable production and integrated afro-pastoral dam management
Our results revealed a strong gender gap in vegetable production systems around agro-pastoral dams in northern Benin. A tailored and gender-specific training programme on sustainable production practices targeted to women will certainly contribute to filling this gap and improving vegetable production around APDs. Indeed, women’s training on improved vegetable production practices can dramatically increase production of leafy vegetables, profitability and income, thus improving women’s livelihoods [44, 45]. This capacity building programme should be supported by increased agricultural extension service support to vegetable farmers around APDs, which could improve technical efficiency of producers . Environmentally friendly solutions and innovations developed by women producers to manage pests and diseases (e.g. botanical extracts) need to be strengthened to reduce health risks for consumers and ensure healthy ecosystems.
Our results also indicated that vegetable producers around APDs were organized into farmer groups or associations, and almost all the respondents belonged to one. However, facilitation to access external support was the main motivation behind group membership, with little concerns about cooperative activities such as mutual support for labour, group marketing strategies, and regular meetings. Promotion of vegetable production around APDs by addressing production bottlenecks and training on sustainable cropping practices could certainly be a driving force in the resurgence of vegetable farmer groups.
Currently, the management of APDs is subject to contestation, and the use of the dams results in recurrent conflicts not only among human stakeholders (e.g. between herders and vegetable producers) but also between humans and wildlife (e.g. human-crocodile conflicts) . Indeed, prior to the 2005 decentralization reforms in Benin, APDs and their management were under the control of the Centre Communal de Promotion Agricole (the Communal Centre for Agriculture Promotion under the Ministry of Agriculture, Livestock production and Fisheries) and their maintenance by the Direction Générale de l’Eau (the General Directorate of Water at the Ministry of Environment, Housing and Urban Planning). Following the decentralization reforms, the control and management of water resources have been transferred to the local government (i.e. the Municipal Assembly or Council) [14, 16, 17, 47]. As a result, the 20 APDs in the Municipality of Nikki are now under the control of the Municipal Council of Nikki . For each APD, a CoGes is put into place by the Municipal Council to ensure the monitoring and maintenance of the APD and to manage and control the access to and use of the APDs’ water and surrounding land so as to prevent siltation and water pollution [14, 17]. However, the ability of CoGes to effectively and sustainably manage the APDs is debatable [14, 16, 17]. Many of the CoGes were inactive or have collapsed [14, 16]. The most recent inventory and assessment of the existing 250 geo-referenced APDs in Benin showed that many of the APDs were not regularly maintained and 44% of them needed urgent rehabilitation of their dyke . Five of the 250 APDs are abandoned and no longer in use . Furthermore, according to many stakeholder groups, in addition to the recurrent conflict between farmers and herders, the siltation and shrinking storage over time have become key impediments to the use of the APDs .
In this complex and conflicting context, developing scenarios for the future of this common resource may be helpful. Scenarios are a useful tool for grappling with the uncertainty and complexity of social-ecological challenges . Rather than predicting what will happen in the future, scenarios are ‘what if?’ stories, which can assist in decision-making and strategic planning . Scenarios can help identify a desired future state for APDs to which to work towards or help prepare for a range of possible futures . We suggest the implementation of the Transformative Scenario Planning approach  to stimulate social learning by enabling all stakeholders and users of APDs, including the municipal council, to engage and discuss options for coping with uncertainty through collaborative actions. The process will help discuss and find a common solution for the recurrent destruction of the vegetable plots, for instance by defining corridors, accepted by all parties, for livestock. The conditions and prerequisites (e.g. availability of irrigation facilities, improved accessibility to the sites through creation of roads) for moving vegetable producers to the downstream sites will also be discussed for sustainable use of the common resource. Additionally, it would be interesting to conduct the transformative scenario planning process per gender to allow a comparative analysis of women and men perspectives for the future of APDs.
In this study, we assessed perception and knowledge of only vegetable producers. It would be interesting to investigate the perception of other users (fishermen, herders, domestic users, crop farmers, etc.) on APD siltation and water quality. This will provide holistic insights on the different stakeholders’ knowledge and perception of the common resource, which will be crucial in the scenario planning process. Further investigation is also needed to empirically quantify the contribution of vegetable production to APD siltation, eutrophication and proliferation of aquatic invasive species, which are becoming a challenge to APDs . This assessment will provide information to inform decision-making regarding whether to move farming activities to downstream sites.
A water quality assessment will also help ascertain dam water quality for the various uses (e.g. agricultural and domestic uses, suitability for crocodiles) and inform policy decision-making at the district level. Contamination level assessments (bacteriological, microbial, and heavy metals) of vegetables produced and fishes from the dams are also needed to evaluate risks for consumers.