Alta De Vos
University of Cape Town
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Featured researches published by Alta De Vos.
Ecological Applications | 2015
Graeme S. Cumming; Craig R. Allen; Natalie C. Ban; Duan Biggs; Harry Biggs; David H. M. Cumming; Alta De Vos; Graham Epstein; Michel Etienne; Kristine Maciejewski; Raphaël Mathevet; Mateja Nenadovic; Michael Schoon
Protected areas (PAs) remain central to the conservation of biodiversity. Classical PAs were conceived as areas that would be set aside to maintain a natural state with minimal human influence. However, global environmental change and growing cross-scale anthropogenic influences mean that PAs can no longer be thought of as ecological islands that function independently of the broader social-ecological system in which they are located. For PAs to be resilient (and to contribute to broader social-ecological resilience), they must be able to adapt to changing social and ecological conditions over time in a way that supports the long-term persistence of populations, communities, and ecosystems of conservation concern. We extend Ostroms social-ecological systems framework to consider the long-term persistence of PAs, as a form of land use embedded in social-ecological systems, with important cross-scale feedbacks. Most notably, we highlight the cross-scale influences and feedbacks on PAs that exist from the local to the global scale, contextualizing PAs within multi-scale social-ecological functional landscapes. Such functional landscapes are integral to understand and manage individual PAs for long-term sustainability. We illustrate our conceptual contribution with three case studies that highlight cross-scale feedbacks and social-ecological interactions in the functioning of PAs and in relation to regional resilience. Our analysis suggests that while ecological, economic, and social processes are often directly relevant to PAs at finer scales, at broader scales, the dominant processes that shape and alter PA resilience are primarily social and economic.
Ecological Applications | 2015
Kristine Maciejewski; Alta De Vos; Graeme S. Cumming; Duan Biggs
Protected areas are a central strategy for achieving global conservation goals, but their continued existence depends heavily on maintaining sufficient social and political support to outweigh economic interests or other motives for land conversion. Thus, the resilience of protected areas can be considered a function of their perceived benefits to society. Nature-based tourism (NBT), a cultural ecosystem service, provides a key source of income to protected areas, facilitating a sustainable solution to conservation. The ability of tourism to generate income depends, however, on both the scales at which this cultural service is provided and the scales at which tourists respond to services on offer. This observation raises a set of location-, context-, and scale-related questions that need to be confronted before we can understand and value cultural service provision appropriately. We combine elements of resilience analysis with a systems ecology framework and apply this to NBT in protected areas to investigate cross-scale interactions and scale mismatches. We postulate that cross-scale effects can either have a positive effect on protected area resilience or lead to scale mismatches, depending on their interactions with cross-scale feedbacks. To demonstrate this, we compare spatial scales and nested levels of institutions to develop a typology of scale mismatches for common scenarios in NBT. In our new typology, the severity of a scale mismatch is expressed as the ratio of spatial scale to institutional level, producing 25 possible outcomes with differing consequences for system resilience. We predict that greater differences between interacting scales and levels, and greater magnitudes of cross-scale interactions, will lead to greater magnitudes of scale mismatch. Achieving a better understanding of feedbacks and mismatches, and finding ways of aligning spatial and institutional scales, will be critical for strengthening the resilience of protected areas that depend on NBT.
Behavioral Ecology and Sociobiology | 2015
Michelle A. Wcisel; M. Justin O’Riain; Alta De Vos; Wilfred Chivell
Refugia play an important role in shaping predator/prey interactions; however, few studies have investigated predator–prey relationships between large marine vertebrates, mainly due to the logistical challenges of studying marine species. The predictable interactions between Cape fur seals and white sharks in South Africa at two neighbouring seal colonies (Seal Island and Geyser Rock) with similar breeding conditions, but distinct adjacent seascapes, offer an opportunity to address this gap. Geyser Rock differs from Seal Island in being surrounded by abundant refugia in the form of kelp beds and shallow reefs, while Seal Island is mostly surrounded by deep open water. In this study, we compare data collected from Geyser Rock to the published data at Seal Island and ask, do seals adjust their anti-predator tactics as a function of landscape features? We found that during periods of high white shark presence, seals at Geyser Rock reduced their presence in open-water and utilized areas that contained complex landscapes around the colony. Although seals at Geyser Rock formed groups when traversing open water, neither group size (high risk median = 4, low risk median = 5) nor temporal movement patterns varied significantly with white shark presence as has been shown at Seal Island. Furthermore, recorded hourly predation rates at Seal Island were 12.5 times higher than at Geyser Rock. Together, these findings suggest that refuge use may be the more effective anti-predator response of seals to a seasonally abundant predator and that the predations at Seal Island reflect a comparative lack of refugia.
Biology Letters | 2010
Alta De Vos; M. Justin O'Riain
Ecology and Society | 2016
Alta De Vos; Graeme S. Cumming; David H. M. Cumming; Judith M. Ament; Julia Baum; Hayley S. Clements; John Grewar; Kristine Maciejewski
Ecosphere | 2016
Alta De Vos; Graeme S. Cumming; Kristine Maciejewski; Gregory D. Duckworth
Behavioral Ecology | 2013
Alta De Vos; M. Justin O’Riain
Marine Mammal Science | 2015
Alta De Vos; M. Justin O'Riain; Michael A. Meÿer; P. Gideon. H. Kotze; Alison A. Kock
Marine Mammal Science | 2015
Alta De Vos; M. Justin O'Riain; Michael A. Meÿer; P. Gideon. H. Kotze; Alison A. Kock
Ecosystem services | 2017
Georgina Cundill; Joana Carlos Bezerra; Alta De Vos; Nokuthula Ntingana