Proposed long-term monitoring protocol and applications for Aloidendron dichotomum populations

Merwe, Helga van der; Geldenhuys, C. J.

doi:10.1016/j.sajb.2017.01.008

Cited by 12 publications

(8 citation statements)

References 19 publications

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Section: Introductionmentioning

confidence: 99%

“…Over the past two decades, the Quiver Tree (Aloidendron dichotomum (Masson), formerly Aloe dichotoma), an iconic longlived stem succulent of the arid western regions of southern Africa (Figure 1), has undergone substantial demographic change (Foden et al, 2007;Hoffman et al, 2010;van der Merwe and Geldenhuys, 2017). Population surveys have shown enhanced mortality of established individuals in the warmer parts of its range (central and equatorward populations), and enhanced population recruitment in the cooler parts (generally the more poleward populations) (Foden et al, 2007;Midgley et al, 2009;Hoffman et al, 2010;van der Merwe and Geldenhuys, 2017). Repeated observations of A. dichotomum population status over several decades, analysis of demographic patterns in relation to expected climate drivers, and consideration of alternative explanations (i.e., protocols meeting the requirements of attribution of range changes to anthropogenic climate change; see Taheri et al, 2021) strongly supports attribution of current population dynamics of A. dichotomum to anthropogenic climate drivers (see Foden, 2002;Foden et al, 2007;van der Merwe and Geldenhuys, 2017).…”

Section: Introductionmentioning

confidence: 99%

“…Population surveys have shown enhanced mortality of established individuals in the warmer parts of its range (central and equatorward populations), and enhanced population recruitment in the cooler parts (generally the more poleward populations) (Foden et al, 2007;Midgley et al, 2009;Hoffman et al, 2010;van der Merwe and Geldenhuys, 2017). Repeated observations of A. dichotomum population status over several decades, analysis of demographic patterns in relation to expected climate drivers, and consideration of alternative explanations (i.e., protocols meeting the requirements of attribution of range changes to anthropogenic climate change; see Taheri et al, 2021) strongly supports attribution of current population dynamics of A. dichotomum to anthropogenic climate drivers (see Foden, 2002;Foden et al, 2007;van der Merwe and Geldenhuys, 2017). Coupled with projected south and southeasterly range expansion in cooler parts of its range (Foden, 2002;Guo et al, 2016), these observations may suggest that a range shift is underway, although this interpretation has been contested (Jack et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…Multiple lines of evidence indicate that A. dichotomum is sensitive to changes in climate (Foden et al, 2007;Hoffman et al, 2010;Guo et al, 2016;van der Merwe and Geldenhuys, 2017). Observations indicate that many populations have not had significant recruitment in the last 50 years, and at sites where limited recruitment has occurred, the timing of seedling establishment correlates with timing of rare favourable climatic windows (Foden, 2002;Hoffman et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Observations indicate that many populations have not had significant recruitment in the last 50 years, and at sites where limited recruitment has occurred, the timing of seedling establishment correlates with timing of rare favourable climatic windows (Foden, 2002;Hoffman et al, 2010). Further, Guo et al (2016) the geographic range of A. dichotomum is constrained by temperature-based variables, indicating the potential vulnerability of this species to changing climate conditions, while the range of the species appears insensitive to rainfall seasonality, with positive population growth rates in both the winter-rainfall and summer-rainfall zones of south-western Africa (Foden et al, 2007;van der Merwe and Geldenhuys, 2017).…”

Section: Introductionmentioning

confidence: 99%

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Broadening Predictive Understanding of Species’ Range Responses to Climate Change: The Case of Aloidendron dichotomum

et al. 2021

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Concerns have been raised about attribution of species range shifts to anthropogenic climate change. Species paleo-range projections are emerging as a means to broaden understanding of range shifts and could be applied to assist in attribution. Apparent recent range contraction in the Quiver Tree (Aloidendron dichotomum (Masson) Klopper and Gideon F.Sm) has been attributed to anthropogenic climate change, but this has been challenged. We simulated the paleo- and future geographic range of A. dichotomum under changing climate using species distribution models (SDMs) to provide a broader perspective on its range dynamics. Ensemble modelling of the Last Glacial Maximum (LGM), mid-Holocene, current, and projected 2070 time periods simulates a paleo-historical poleward expansion of suitable bioclimatic space for this species under natural climate change post-LGM, and projects an eastward shift towards 2070. During the LGM, suitable bioclimatic space for A. dichotomum was simulated to be restricted to the equatorward part of its current range. During the Pleistocene/mid-Holocene climate transition period, the species’ range is predicted to have expanded significantly polewards at an average rate of 0.4 km per decade, assuming constant tracking of its optimal climatic niche. By 2070, suitable bioclimatic space is projected to expand further eastward into the summer rainfall region of South Africa, and contract in its equatorward reaches. Simulated post-LGM shifts roughly match expectations based on preliminary phylogenetic information, further supporting the attribution of current population declines to anthropogenic climate change drivers. Equatorward populations are required to migrate south-eastwards at a rate roughly 15 times faster than that calculated for the LGM/mid-Holocene climate transition period to avoid local extirpation. A preliminary analysis of range-wide genetic variation reveals a cline of variation, with generally higher levels in the central and more northerly part of the species distribution, as expected from the proposed paleo-range of the species. A more detailed analysis of the species’ phylogeographic history could be used to test the proposed paleo-range dynamics presented here, and if confirmed, would provide strong support for the use of this species as an indicator of anthropogenic climate change and a powerful case study for testing the implementation of conservation actions.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Broadening Predictive Understanding of Species’ Range Responses to Climate Change: The Case of Aloidendron dichotomum

et al. 2021

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Managing biodiversity in the Anthropocene: discussing the Nature Futures Framework as a tool for adaptive decision-making for nature under climate change

Palacios‐Abrantes

Badhe²,

Bamford

et al. 2022

Sustain Sci

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Conservation approaches to social-ecological systems have largely been informed by a framing of preserving nature for its instrumental societal benefits, often ignoring the complex relationship of humans and nature and how climate change might impact these. The Nature Futures Framework (NFF) was developed by the Task Force on scenarios and models of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services as a heuristic approach that appreciates the diverse positive values of nature and its contribution to people. In this overview, we convene a group of experts to discuss the NFF as a tool to inform management in social-ecological systems facing climate change. We focus on three illustrative case studies from the global south across a range of climate change impacts at different ecological levels. We find that the NFF can facilitate the identification of trade-offs between alternative climate adaptation pathways based on different perspectives on the values of nature they emphasize. However, we also identify challenges in adopting the NFF, including how outputs can be translated into modeling frameworks. We conclude that using the NFF to unpack diverse management options under climate change is useful, but that there are still gaps where more work needs to be done to make it fully operational. A key conclusion is that a range of multiple perspectives of people’s values on nature could result in adaptive decision-making and policy that is resilient in responding to climate change impacts in social-ecological systems.

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Succulent Karoo Biome

Grey

Midgley

2024

Encyclopedia of Biodiversity

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Proposed long-term monitoring protocol and applications for Aloidendron dichotomum populations

Cited by 12 publications

References 19 publications

Broadening Predictive Understanding of Species’ Range Responses to Climate Change: The Case of Aloidendron dichotomum

Broadening Predictive Understanding of Species’ Range Responses to Climate Change: The Case of Aloidendron dichotomum

Managing biodiversity in the Anthropocene: discussing the Nature Futures Framework as a tool for adaptive decision-making for nature under climate change

Succulent Karoo Biome

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