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1.
J Exp Bot ; 73(22): 7434-7449, 2022 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-36066187

RESUMO

Aloidendron dichotomum appears to be undergoing the early stages of a range shift in response to anthropogenic climate change in south-western Africa. High mortality has been recorded in warmer populations, while population expansions have been recorded in cooler poleward parts of its range. This study aimed to determine the key environmental controls on A. dichotomum photosynthesis in areas of population expansion, to inform the potential attribution of directional population expansion to anthropogenic warming. Nocturnal acid accumulation and CO2 assimilation were measured in individuals growing under a range of temperature and watering treatments in a greenhouse experiment. In addition, nocturnal acid accumulation and phosphoenolpyruvate carboxylase activity were quantified in two wild populations at the most southerly and south-easterly range extents. Multiple lines of evidence confirmed that A. dichotomum performs Crassulacean acid metabolism. Total nocturnal acid accumulation was highest at night-time temperatures of ~21.5 °C, regardless of soil water availability, and night-time CO2 assimilation rates increased with leaf temperature, suggesting a causal link to the cool southern range limit. Leaf acidity at the start of the dark period was highly predictive of nocturnal acid accumulation in all individuals, implicating light availability during the day as an important determinant of nocturnal acid accumulation.


Assuntos
Árvores , África do Sul
2.
Conserv Biol ; 36(5): e13941, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-35648687

RESUMO

Climate change is challenging the ability of protected areas (PAs) to meet their objectives. To improve PA planning, we developed a framework for assessing PA vulnerability to climate change based on consideration of potential climate change impacts on species and their habitats and resource use. Furthermore, the capacity of PAs to adapt to these climate threats was determined through assessment of PA management effectiveness, adjacent land use, and financial resilience. Users reach a PA-specific vulnerability score and rank based on scoring of these categories. We applied the framework to South Africa's 19 national parks. Because the 19 parks are managed as a national network, we explored how resources might be best allocated to address climate change. Each park's importance to the network's biodiversity conservation and revenue generation was estimated and used to weight overall vulnerability scores and ranks. Park vulnerability profiles showed distinct combinations of potential impacts of climate change and adaptive capacities; the former had a greater influence on vulnerability. Mapungubwe National Park emerged as the most vulnerable to climate change, despite its relatively high adaptive capacity, largely owing to large projected changes in species and resource use. Table Mountain National Park scored the lowest in overall vulnerability. Climate change vulnerability rankings differed markedly once importance weightings were applied; Kruger National Park was the most vulnerable under both importance scenarios. Climate change vulnerability assessment is fundamental to effective adaptation planning. Our PA assessment tool is the only tool that quantifies PA vulnerability to climate change in a comparative index. It may be used in data-rich and data-poor contexts to prioritize resource allocation across PA networks and can be applied from local to global scales.


Resumen El cambio climático es un gran obstáculo para que las áreas protegidas (AP) logren sus objetivos. Para mejorar la planeación de las AP, desarrollamos un marco de trabajo para evaluar la vulnerabilidad de estas ante el cambio climático con base en la consideración de los impactos potenciales del cambio climático sobre las especies, sus hábitats y los recursos que usan. Además, determinamos la capacidad de las AP para adaptarse a estas amenazas climáticas mediante la valoración de las categorías efectividad de la gestión de las AP, las tierras adyacentes y la resiliencia económica. Los usuarios logran un puntaje y clasificación de vulnerabilidad específicas de la AP con base en las calificaciones de estas categorías. Aplicamos el marco de trabajo a los 19 parques nacionales de Sudáfrica. Ya que todos los parques se manejan como una red nacional, exploramos cómo pueden asignarse de mejor manera los recursos para lidiar con el cambio climático. Se estimaron la importancia de cada parque para la conservación de la biodiversidad de la red y la generación de ganancias. Después usamos las estimaciones para sopesar los puntajes y las clasificaciones generales de vulnerabilidad. Los perfiles de vulnerabilidad de los parques mostraron combinaciones distintivas de impactos potenciales del cambio climático y capacidades de adaptación; los impactos tuvieron una mayor influencia sobre la vulnerabilidad. El Parque Nacional Mapungubwe se ubicó como el más vulnerable ante el cambio climático, a pesar de tener una capacidad de adaptación relativamente alta, principalmente debida a grandes cambios proyectados para el uso de recursos y especies. El Parque Nacional Table Mountain tuvo el puntaje más bajo de vulnerabilidad generalizada. Las clasificaciones de vulnerabilidad al cambio climático difirieron notablemente una vez que se aplicaron los factores de importancia; el Parque Nacional Kruger fue el más vulnerable bajo ambos escenarios de importancia. La evaluación de vulnerabilidad al cambio climático es fundamental para la planeación efectiva de la adaptación. Nuestra herramienta de valoración de las AP es la única que cuantifica la vulnerabilidad de las AP al cambio climático en un índice comparativo. Puede usarse en contextos con muchos o pocos datos para priorizar la asignación de recursos en las redes de AP y puede aplicarse desde la escala local hasta la mundial.


Assuntos
Mudança Climática , Parques Recreativos , Biodiversidade , Conservação dos Recursos Naturais , Ecossistema , África do Sul
3.
Proc Biol Sci ; 284(1862)2017 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-28904135

RESUMO

Mitigation of anthropogenic climate change involves deployments of renewable energy worldwide, including wind farms, which can pose a significant collision risk to volant animals. Most studies into the collision risk between species and wind turbines, however, have taken place in industrialized countries. Potential effects for many locations and species therefore remain unclear. To redress this gap, we conducted a systematic literature review of recorded collisions between birds and bats and wind turbines within developed countries. We related collision rate to species-level traits and turbine characteristics to quantify the potential vulnerability of 9538 bird and 888 bat species globally. Avian collision rate was affected by migratory strategy, dispersal distance and habitat associations, and bat collision rates were influenced by dispersal distance. For birds and bats, larger turbine capacity (megawatts) increased collision rates; however, deploying a smaller number of large turbines with greater energy output reduced total collision risk per unit energy output, although bat mortality increased again with the largest turbines. Areas with high concentrations of vulnerable species were also identified, including migration corridors. Our results can therefore guide wind farm design and location to reduce the risk of large-scale animal mortality. This is the first quantitative global assessment of the relative collision vulnerability of species groups with wind turbines, providing valuable guidance for minimizing potentially serious negative impacts on biodiversity.


Assuntos
Aves , Quirópteros , Mortalidade , Centrais Elétricas , Energia Renovável , Vento , Distribuição Animal , Migração Animal , Animais , Mudança Climática , Ecossistema
4.
Conserv Biol ; 31(5): 1008-1017, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28225163

RESUMO

We examine issues to consider when reframing conservation science and practice in the context of global change. New framings of the links between ecosystems and society are emerging that are changing peoples' values and expectations of nature, resulting in plural perspectives on conservation. Reframing conservation for global change can thus be regarded as a stage in the evolving relationship between people and nature rather than some recent trend. New models of how conservation links with transformative adaptation include how decision contexts for conservation can be reframed and integrated with an adaptation pathways approach to create new options for global-change-ready conservation. New relationships for conservation science and governance include coproduction of knowledge that supports social learning. New processes for implementing adaptation for conservation outcomes include deliberate practices used to develop new strategies, shift world views, work with conflict, address power and intergenerational equity in decisions, and build consciousness and creativity that empower agents to act. We argue that reframing conservation for global change requires scientists and practitioners to implement approaches unconstrained by discipline and sectoral boundaries, geopolitical polarities, or technical problematization. We consider a stronger focus on inclusive creation of knowledge and the interaction of this knowledge with societal values and rules is likely to result in conservation science and practice that meets the challenges of a postnormal world.


Assuntos
Conservação dos Recursos Naturais , Ecossistema , Humanos
5.
Science ; 354(6313)2016 11 11.
Artigo em Inglês | MEDLINE | ID: mdl-27846577

RESUMO

Most ecological processes now show responses to anthropogenic climate change. In terrestrial, freshwater, and marine ecosystems, species are changing genetically, physiologically, morphologically, and phenologically and are shifting their distributions, which affects food webs and results in new interactions. Disruptions scale from the gene to the ecosystem and have documented consequences for people, including unpredictable fisheries and crop yields, loss of genetic diversity in wild crop varieties, and increasing impacts of pests and diseases. In addition to the more easily observed changes, such as shifts in flowering phenology, we argue that many hidden dynamics, such as genetic changes, are also taking place. Understanding shifts in ecological processes can guide human adaptation strategies. In addition to reducing greenhouse gases, climate action and policy must therefore focus equally on strategies that safeguard biodiversity and ecosystems.


Assuntos
Aclimatação , Biodiversidade , Mudança Climática , Variação Genética , Animais , Produtos Agrícolas/genética , Pesqueiros , Cadeia Alimentar , Água Doce , Humanos , Dinâmica Populacional , Razão de Masculinidade
6.
J Biogeogr ; 41(4): 724-735, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25505356

RESUMO

AIM: Climate change can lead to decreased climatic suitability within species' distributions, increased fragmentation of climatically suitable space, and/or emergence of newly suitable areas outside present distributions. Each of these extrinsic threats and opportunities potentially interacts with specific intrinsic traits of species, yet this specificity is seldom considered in risk assessments. We present an analytical framework for examining projections of climate change-induced threats and opportunities with reference to traits that are likely to mediate species' responses, and illustrate the applicability of the framework. LOCATION: Sub-Saharan Africa. METHODS: We applied the framework to 195 sub-Saharan African amphibians with both available bioclimatic envelope model projections for the mid-21st century and trait data. Excluded were 500 narrow-ranging species mainly from montane areas. For each of projected losses, increased fragmentation and gains of climate space, we selected potential response-mediating traits and examined the spatial overlap with vulnerability due to these traits. We examined the overlap for all species, and individually for groups of species with different combinations of threats and opportunities. RESULTS: In the Congo Basin and arid Southern Africa, projected losses for wide-ranging amphibians were compounded by sensitivity to climatic variation, and expected gains were precluded by poor dispersal ability. The spatial overlap between exposure and vulnerability was more pronounced for species projected to have their climate space contracting in situ or shifting to distant geographical areas. Our results exclude the potential exposure of narrow-ranging species to shrinking climates in the African tropical mountains. MAIN CONCLUSIONS: We illustrate the application of a framework combining spatial projections of climate change exposure with traits that are likely to mediate species' responses. Although the proposed framework carries several assumptions that require further scrutiny, its application adds a degree of realism to familiar assessments that consider all species to be equally affected by climate change-induced threats and opportunities.

7.
PLoS One ; 8(6): e65427, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23950785

RESUMO

Climate change will have far-reaching impacts on biodiversity, including increasing extinction rates. Current approaches to quantifying such impacts focus on measuring exposure to climatic change and largely ignore the biological differences between species that may significantly increase or reduce their vulnerability. To address this, we present a framework for assessing three dimensions of climate change vulnerability, namely sensitivity, exposure and adaptive capacity; this draws on species' biological traits and their modeled exposure to projected climatic changes. In the largest such assessment to date, we applied this approach to each of the world's birds, amphibians and corals (16,857 species). The resulting assessments identify the species with greatest relative vulnerability to climate change and the geographic areas in which they are concentrated, including the Amazon basin for amphibians and birds, and the central Indo-west Pacific (Coral Triangle) for corals. We found that high concentration areas for species with traits conferring highest sensitivity and lowest adaptive capacity differ from those of highly exposed species, and we identify areas where exposure-based assessments alone may over or under-estimate climate change impacts. We found that 608-851 bird (6-9%), 670-933 amphibian (11-15%), and 47-73 coral species (6-9%) are both highly climate change vulnerable and already threatened with extinction on the IUCN Red List. The remaining highly climate change vulnerable species represent new priorities for conservation. Fewer species are highly climate change vulnerable under lower IPCC SRES emissions scenarios, indicating that reducing greenhouse emissions will reduce climate change driven extinctions. Our study answers the growing call for a more biologically and ecologically inclusive approach to assessing climate change vulnerability. By facilitating independent assessment of the three dimensions of climate change vulnerability, our approach can be used to devise species and area-specific conservation interventions and indices. The priorities we identify will strengthen global strategies to mitigate climate change impacts.


Assuntos
Anfíbios/fisiologia , Antozoários/fisiologia , Aves/fisiologia , Mudança Climática , Aclimatação , Animais , Biodiversidade , Conservação dos Recursos Naturais/métodos
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