title: Twenty-five years of change in southern African passerine diversity: nonclimatic factors of change.
abstract: We analysed more than 25 years of change in passerine bird distribution in South Africa, Swaziland and Lesotho, to show that species distributions can be influenced by processes that are at least in part independent of the local strength and direction of climate change: land use and ecological succession. We used occupancy models that separate species' detection from species' occupancy probability, fitted to citizen science data from both phases of the Southern African Bird Atlas Project (1987-1996 and 2007-2013). Temporal trends in species' occupancy probability were interpreted in terms of local extinction/colonization, and temporal trends in detection probability were interpreted in terms of change in abundance. We found for the first time at this scale that, as predicted in the context of bush encroachment, closed-savannah specialists increased where open-savannah specialists decreased. In addition, the trend in the abundance of species a priori thought to be favoured by agricultural conversion was negatively correlated with human population density, which is in line with hypotheses explaining the decline in farmland birds in the Northern Hemisphere. In addition to climate, vegetation cover and the intensity and time since agricultural conversion constitute important predictors of biodiversity changes in the region. Their inclusion will improve the reliability of predictive models of species distribution.
authors.affiliation: Department of Statistical Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Péron
authors.affiliation: Department of Statistical Sciences, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.|African Climate and Development Initiative, University of Cape Town, Rondebosch 7701, Cape Town, South Africa.
authors.forename: Res
authors.initials: R
authors.lastname: Altwegg
mesh_terms: D000383:Agriculture; D063147:Animal Distribution; D000818:Animals; D044822:Biodiversity; D003247:Conservation of Natural Resources; D017753:Ecosystem; D013541:Eswatini; D007927:Lesotho; D008954:Models, Biological; D046109:Passeriformes / Q000502:physiology*; D011157:Population Dynamics; D012621:Seasons; D013019:South Africa; D013997:Time Factors
keywords: South Africa; biodiversity; bush encroachment; citizen science; climate change; conservation planning; occupancy models; pesticide accumulation; species richness