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Abstract Ecologically specialized plants are expected to be at greater risk of extinction than generalists due to climate change. Such risk is greatest in biodiversity hotspots such as the Greater Cape Floristic Region (GCFR), which accommodates both ecological specialists and generalists. Thesium L., a genus with the highest number of species in Santalaceae and the most diverse in Africa, offers an appropriate system for evaluating both the correlates of range extent and specialization and the relative extinction risks associated with both. We hypothesized that range size, ecological specialization, and consequent climatically modulated extinction risks are all phylogenetically structured, such that climate change will precipitate a disproportionate loss of phylogenetic diversity in the GCFR Thesium. Past and future species distribution ranges were predicted using MaxEnt models based on present‐day occurrences and environmental conditions. Of the 101 Thesium species modeled, 70% have had large range sizes during the Last Glacial Maximum (LGM), 50% currently have a large range size, and future conditions are predicted to allow 40% to obtain large range sizes. Between the LGM and the present, 17% of species are thought to have undergone a contraction of available range space in the present time whereas 37% are expected to expand their ranges into the future, while 51% of species will experience range contractions. Of the 65 species currently ranked as Least Concern in the South African Red List, 24% will likely shift into higher extinction risk categories. Interestingly, 8.5% of ecological specialists, although having experienced a range reduction from the LGM to the present, are predicted to persist in the face of future climate change. However, the range extent, ecological specialization, and extinction risk are phylogenetically random and therefore should have a negligible impact on the phylogenetic diversity of the GCFR Thesium.

• This research shows the potential land-use transition for twenty land-based mitigation options and their impacts on biodiversity. • A case-scenario analysis to assess carbon sequestration and biodiversity loss of land-based mitigation options. • Synergies between land-based mitigation options and biodiversity protection to comply with the Paris Agreement. • The results are relevant to reinforce biodiversity conservation and to determine the regions with large land-based mitigation potential. The Paris Agreement to keep global temperature increase to well-below 2 °C and to pursue efforts to limit it to 1.5 °C requires to formulate ambitious climate-change mitigation scenarios to reduce CO 2 emissions and to enhance carbon sequestration. These scenarios likely require significant land-use change. Failing to mitigate climate change will result in an unprecedented warming with significant biodiversity loss. The mitigation potential on land is high. However, how land-based mitigation options potentially affect biodiversity is poorly understood. Some land-based mitigation options could also counter the biodiversity loss. Here we reviewed the recently scientific literature to assess twenty land-based mitigation options that are implemented in different mitigation pathways to comply with the Paris Agreement for their biodiversity impacts by using the Mean Species Abundance (MSA LU) indicator for land use. We showed the likely land-use transition and potential MSA LU changes for each option, compared their carbon sequestration opportunities (tC per ha) and assessed the resulting biodiversity change in two case scenarios. Our results showed that most options benefit biodiversity. Reforestation of cultivated and managed areas together with restoration of wetlands deliver the largest MSA LU increases, if land is allowed to reach a mature state over time. A quarter of the assessed options, including intensification of agricultural areas and bioenergy with carbon capture and storage, decreased MSA LU. Options, such as afforestation and reduced deforestation, either positively or negatively affected MSA LU. This depends on their local implementation and adopted forest-conservation schemes. Comparing the different options showed that avoiding deforestation by implementing agroforestry at the expense of pastures delivered both the largest MSA LU increases and the highest carbon sequestration opportunities. However, agroforestry that leads to deforestation, enhanced carbon sequestration slightly but with a marginal MSA LU increase. This stresses the importance of avoiding forest conversion. Our study advances the understanding on current and future benefits and adverse effects of land-based mitigation options on biodiversity. This certainly helps biodiversity conservation and determines the regions with large land-based mitigation potential. [ABSTRACT FROM AUTHOR]