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El CSIC advierte de que la biodiversidad de los ecosistemas alpinos africanos está en extinción por la presión humana

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The conservation of tropical montane biodiversity requires a holistic approach, using genetic, ecological and geographic information to understand the effects of environmental changes across temporal scales and simultaneously addressing the impacts of multiple threats. This problem is especially acute in understudied and highly threatened areas like the Ethiopian Highlands, where accelerated land conversion and degradation is placing further pressures on biodiversity.

While climate change is recognized as a major future threat to biodiversity, most species are currently threatened by extensive human?induced habitat loss, fragmentation and degradation. Tropical high?altitude alpine and montane forest ecosystems and their biodiversity are particularly sensitive to temperature increases under climate change, but they are also subject to accelerated pressures from land conversion and degradation due to a growing human population.

A research team have studied the combined effects of anthropogenic land?use change, past and future climate changes and mountain range isolation on the endemic Ethiopian Highlands long?eared bat, Plecotus balensis, an understudied bat that is restricted to the remnant natural high?altitude Afroalpine and Afromontane habitats.

The EBD researcher Javier Juste participated in this study, together with the University of Exeter and the University of Stirling, in the United Kingdom; Dire Dawa University in Ethiopia; the Center for Research in Biodiversity and Genetic Resources (CIBIO), Veirão, and the University of Porto, in Portugal; and the CIBER of Epidemiology and Public Health, of Madrid.

The research team integrated ecological niche modelling, landscape genetics and model?based inference to assess the genetic, geographic and demographic impacts of past and recent environmental changes. They show that mountain range isolation and historic climates shaped population structure and patterns of genetic variation, but recent anthropogenic land?use change and habitat degradation are associated with a severe population decline and loss of genetic diversity.

Models predict that the suitable niche of this bat has been progressively shrinking since the last glaciation period. This study highlights threats to Afroalpine and Afromontane biodiversity, squeezed to higher altitudes under climate change while losing genetic diversity and suffering population declines due to anthropogenic land?use change.

The study concludes that the conservation of tropical montane biodiversity requires a holistic approach, using genetic, ecological and geographic information to understand the effects of environmental changes across temporal scales and simultaneously addressing the impacts of multiple threats.

 

informacion[at]ebd.csic.es

REFERENCIA:

Orly Razgour, Mohammed Kasso, Helena Santos, Javier Juste (2020) Threats to Afromontane biodiversity from climate change and habitat loss revealed by genetic monitoring of the Ethiopian Hi ghlands bat. Evolutionary applications. DOI: 10.1111/eva.13161

Read full press release (Spanish)
 


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Strategies shrubby junipers adopt to tolerate drought differ by site

Strategies shrubby junipers adopt to tolerate drought differ by site

Drought-induced dieback episodes are globally reported among forest ecosystems but they have been understudied in scrublands. Chronically-stressed individuals are supposed to be more vulnerable prior to drought which triggers death. Drought-triggered dieback and mortality events affecting Mediterranean Juniperus phoenicea scrublands were analyzed in two sites with contrasting climate and soil conditions located in Spain. The radial growth patterns of coexisting living and dead junipers, including the calculation of growth statistics used as early-warning signals, quantified growth response to climate, were characterized and the wood C and O isotope discrimination was analyzed. In the inland, continental site with rocky substrates (Yaso, Huesca, N Spain), dead junipers grew less than living junipers about three decades prior to the dieback started in 2016. However, in the coastal, mild site with sandy soils (Doñana, Huelva, SW Spain), dead junipers were smaller but grew more than living junipers about two decades before the dieback onset in 2005. The only common patterns between sites were the higher growth coherence in both living and dead junipers prior to the dieback, and the decrease in growth persistence of dead junipers. Cool and wet conditions in the prior winter and current spring, and cool summer conditions enhanced juniper growth. In Doñana, growth of living individuals was more reduced by warm July conditions than in the case of dead individuals. Higher ?13C values in Yaso indicate also more pronounced drought stress. In Yaso, dead junipers presented lower ?18O values, but the opposite occurred in Doñana suggesting different changes in stomatal conductance prior to death. Warm summer conditions enhance evapotranspiration rates and trigger dieback in this shallow-rooted species, particularly in sites with a poor water-holding capacity. Chronic, slow growth is not always a reliable predictor of drought-triggered mortality. informacion[at]ebd.csic.es: Camarero et al (2020) Dieback and mortality of junipers caused by drought: Dissimilar growth and wood isotope patterns preceding shrub death. Agr Forest Meteorol 291, 108078. DOI 10.1016/j.agrformet.2020.108078


https://www.sciencedirect.com/science/article/pii/S0168192320301805?dgcid=author#ack0001