Browsing by Author "Hofmeyr, Sally"

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    Citizen Science Week: 8–16 March 2014
    (2014-03) Hofmeyr, Sally
    To celebrate Open Education Week (10–15 March), the Animal Demography Unit (ADU) is holding a Citizen Science Week (see this post for details about the ADU and citizen science as well as this Citizen Science Week FB post). This additional celebration runs during Open Education Week but also includes the weekends at either end (8–16 March). The weekends are included because, for many people, they are the best time of the week to practise citizen science! The ADU is heavily involved in open education, but in a rather different way from how most people probably expect open education to work.
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    Large Terrestrial Birds
    (2014-09-12) Hofmeyr, Sally; Neary, Tim
    In this radio broadcast, Sally Hofmeyr discusses the Coordinated Aviafaunal Roadcount programme, which maps populations of large terrestrial birds in agricultural areas. This programme supplies demographic data that can be used to inform conservation efforts and stimulate further research into declining or endangered populations. Sally discusses are methodological considerations required in order to make the information gathered from the approximately 800 citizen scientists are involved in the projects most useful, as well as the effect of farming on large terrestrial bird demography. Image provided courtesy of Brian Snelson under a Creative Commons Attribution 2.0 Generic license.
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    Tails through time: leopard population dynamics in the Little Karoo
    (2024) Steyn, Lawrence; Williams, Kathryn; Distiller, Gregory; Hofmeyr, Sally; Mann, Gareth; Wilkinson, Anita
    Large carnivores play a vital role in structuring our ecosystems, yet they face mounting threats such as habitat loss, prey reduction and persecution. These threats reduce their global distribution and impacts their population numbers. Protected areas can offer refuge for large carnivores, however leopards (Panthera pardus), can persist outside of these areas and often occupy mixed-use landscapes. Our understanding of how leopards persist over time in mixed-use landscapes is limited, especially in the semi-arid regions of southern Africa. This study, to the best of my knowledge, is the only multi-session maximum likelihood spatial capture-recapture (SCR) analysis to have been conducted in a semi-arid environment outside of a protected area in Southern Africa. The study aimed to estimate leopard population changes over time and to investigate the possible drivers affecting density, using three surveys (2012, 2017, 2022), in the mixed-use landscape of the Little Karoo in the Western Cape, South Africa. In 2012, a total of 141 paired camera stations were used for a total of 13,050 trap days resulting in 29 unique leopard captures. In 2017, a total of 40 paired camera stations were used for a total of 2,128 trap days resulting in 18 unique leopard captures and in 2022 a total of 64 paired camera stations were used for a total of 8,997 trap days resulting in 37 unique leopard captures. The best performing density model indicated an increasing population trend over the study period which included a trend term on density (D~year) and an interaction term (individual session*sex) on λ0 (capture rate) and σ (spatial decay). Density estimates (Standard Error) for leopard populations for the three surveys 2012, 2017, and 2022, were 0.52 (± 0.11), 0.70 (± 0.08), and 0.95 (± 0.08) leopards per 100 km2, respectively. Terrain ruggedness, elevation, vegetation type and distance from major rivers were all important drivers in leopard density in the Little Karoo. Indicating that high lying areas provide suitable refuge for leopards and are key areas for movement corridor planning. These density estimates are similar to previous single maximum likelihood SCR density estimate studies in the Little Karoo and the Western Cape province. Results from this study indicate the leopards have persisted in the Little Karoo over the study period and suggest that the population may be increasing. Further research on what is driving this population shift is needed, but the results serve as an encouraging sign for leopard conservation in the Little Karoo
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    Tails through time: leopard population dynamics in the Little Karoo
    (2024) Steyn, Lawrence; Williams, Kathryn; Distiller, Gregory; Hofmeyr, Sally; Mann, Gareth; Wilkinson, Anita
    Large carnivores play a vital role in structuring our ecosystems, yet they face mounting threats such as habitat loss, prey reduction and persecution. These threats reduce their global distribution and impacts their population numbers. Protected areas can offer refuge for large carnivores, however leopards (Panthera pardus), can persist outside of these areas and often occupy mixed-use landscapes. Our understanding of how leopards persist over time in mixed-use landscapes is limited, especially in the semi-arid regions of southern Africa. This study, to the best of my knowledge, is the only multi-session maximum likelihood spatial capture-recapture (SCR) analysis to have been conducted in a semi-arid environment outside of a protected area in Southern Africa. The study aimed to estimate leopard population changes over time and to investigate the possible drivers affecting density, using three surveys (2012, 2017, 2022), in the mixed-use landscape of the Little Karoo in the Western Cape, South Africa. In 2012, a total of 141 paired camera stations were used for a total of 13,050 trap days resulting in 29 unique leopard captures. In 2017, a total of 40 paired camera stations were used for a total of 2,128 trap days resulting in 18 unique leopard captures and in 2022 a total of 64 paired camera stations were used for a total of 8,997 trap days resulting in 37 unique leopard captures. The best performing density model indicated an increasing population trend over the study period which included a trend term on density (D~year) and an interaction term (individual session*sex) on λ0 (capture rate) and σ (spatial decay). Density estimates (Standard Error) for leopard populations for the three surveys 2012, 2017, and 2022, were 0.52 (± 0.11), 0.70 (± 0.08), and 0.95 (± 0.08) leopards per 100 km2, respectively. Terrain ruggedness, elevation, vegetation type and distance from major rivers were all important drivers in leopard density in the Little Karoo. Indicating that high lying areas provide suitable refuge for leopards and are key areas for movement corridor planning. These density estimates are similar to previous single maximum likelihood SCR density estimate studies in the Little Karoo and the Western Cape province. Results from this study indicate the leopards have persisted in the Little Karoo over the study period and suggest that the population may be increasing. Further research on what is driving this population shift is needed, but the results serve as an encouraging sign for leopard conservation in the Little Karoo
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    Translational Research Communication: a new experience
    (2014-04) Hofmeyr, Sally
    Academics are like optical fibre. They generate communication about their research along exceptionally narrow channels. Their research communication is almost exclusively focused on their discipline – to their conferences and their journals. In today's world, though, in order for academics to remain relevant and succeed in finding funding and institutional support, that fibre must expand to become a funnel, or if you like, a trumpet. Academics need to be able to make their research accessible to a broader community. This is not a luxury or an add-on; it is essential for the survival of the species.