Ideal Free Distributions of Mobile Pastoralists in Multiple Seasonal Grazing Areas
Abstract The pastoral system in the Far North Region of Cameroon is best described as an open system in which mobile pastoralists have open access to common-pool grazing resources. We hypothesized that there is a self-organizing management system of open access to common-pool grazing resources and predicted that we would find an Ideal Free Distribution (IFD) of mobile pastoralists within seasonal grazing areas. In this paper we used mobility data and remote sensing data from two seasonal grazing areas at the end of the dry season in three consecutive years to evaluate that hypothesis. We found evidence of an IFD in the two seasonal grazing areas of the Logone Floodplain and the Lake Maga area. These findings offer further support for our hypothesis that there is a complex adaptive system in which pastoralists distribute themselves effectively over available grazing resources.
Rangeland governance in an open system: Protecting transhumance corridors in the Far North Province of Cameroon
The mobile pastoral system in the far north region of Cameroon is an excellent example of the paradox of pastoral land tenure, in that pastoralists need secure access to pasture and water, but also flexibility in resource use, i.e. the ability to move elsewhere because of spatio-temporal variation in resource availability. In this paper, we draw from our collective research and development experience with mobile pastoralists and discuss how non-governmental organisations have used ordinances and bureaucratic procedures to protect pastoral resources, in particular transhumance corridors that connect seasonal grazing lands in the far north region. We argue that the mobile pastoral system is best understood as an open system and explain what the implications are for the protection of pastoral resources. We argue that delimiting and protecting transhumance corridors is not the panacea, and we conclude with a discussion of the advantages and disadvantages of this approach.
Pathology of tail fan necrosis in the spiny lobster, Jasus edwardsii.
Tail fan necrosis (TFN) is the bacterial infection of the tail fan of spiny lobsters which leads to melanosis and erosion of the tail fan tissues. The condition is commonly found among spiny lobsters in aquaculture and commercial fisheries, and greatly reduces their commercial value. This study describes the pathology of TFN by examining the tail fans (telson, uropods) and internal organs (mid-gut, hepatopancreas, heart and gill) of 29 affected wild spiny lobsters (Jasus edwardsii) and 14 unaffected in New Zealand. Initial signs of TFN were observed around the margins of lacerations to the tail fan, with more extensive signs extending from these presumptive sites of initiation. The establishment of the condition at points of injury is consistent with the penetration of TFN through the cuticle and tissue layers of the affected tail fans, which is rarely seen in other forms of shell disease. Entry into these tissues was characterised initially by caseous necrosis and haemocyte accumulation, followed by the spread of these responses together with melanisation. Additional pathological changes to the tail fans included pseudomembrane formation, detachment of epidermis or cuticle, clotted haemolymph and fibrosis. Among internal organs, pathological changes were found in a total of two mid-gut, four heart and two gill samples from eight lobsters with TFN, while no suspected changes were found in the organs of lobsters without TFN. The causes of internal organ pathology associated with TFN in spiny lobsters warrants more detailed research.