Abstract:
Agricultural intensification is a threat to terrestrial ecosystems around the world. Agricultural areas, especially
monocultures, create homogenous landscapes for wildlife. However, certain crops, such as sugarcane, are harvested
in phases, creating a mosaic of fields in different stages of growth. We investigated changes in avian
communities across four different sugarcane growth stages: emerging, short, medium and tall sugarcane, as well
as control sites that represented native savanna habitat in northeast Eswatini prior to conversion to agriculture. In
total, we sampled nine sites in sugarcane fields (at different growth stages) and three in native savanna. We
conducted bird counts at 5-week intervals along 200m line transects over both the breeding and non-breeding
seasons. We recorded a total of 124 bird species belonging to 58 families. Bird species richness and diversity
were higher in savannas compared to any stages of growth in sugarcane. In contrast, functional beta diversity and
uniqueness were higher in sugarcane than in savanna. Community composition was also different between the
two land-uses. While there was overlap in bird species composition between different sugarcane growth stages,
there was high beta diversity and high turnover between sites, indicative of the high temporal and spatial variability
in bird communities in sugarcane fields. We demonstrated that the spatial and temporal variability created
by the different growth stages of sugarcane promotes the occurrence of species with different traits, which may
contribute to ecosystem functioning and promote the conservation of bird species as sugarcane fields can provide
resource complementation for species with different needs.
