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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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Combined effects of global change on bumblebees

Combined effects of global change on bumblebees

The decline in bee populations has recently attracted much attention from researchers, conservationists and the general public, with insect-mediated pollination being a key process for terrestrial ecosystems as well as for crop production. The conclusions of different studies suggest that this decline is the result of pressures from different drivers of global change such as habitat destruction, pesticide use and climate warming. However, there is increasing evidence that these pressures do not act in isolation, and may have complex interactive effects beyond the sum of their individual effects. The interactive effect on bumblebee colonies of three of these global change pressures was explored: climate change, exposure to pesticides, and landscape transformation, through a series of field experiments that simulate these global change drivers independently and in combination. In this work, the joint effect of these stressors on the reproductive capacity of the colonies is analysed. The results show that bumblebees have larger reproductive success at high temperatures, but only when there are abundant floral resources. In addition, exposure to pesticides was observed to produce a decrease in the number of males. Furthermore, the size of both queens and workers increased at high temperatures but the size of queens decreased with increased floral resources. Interestingly, bumblebees increased the investment in wax and silk used to protect queen cocoons from high temperatures, and need to actively ventilate the colonies using workers that fan their wings at the colony entrance. These two mechanisms may cushion the negative impacts of high temperatures by either better insulating the colony or reducing heat excess. However, these kinds of responses may be only affordable when resources are not limiting. This experiment suggests that the interaction between different stressors may not be additive and that the mechanisms to cushion some of the impacts may not be enough when multiple stressors act simultaneously. informacion[at]ebd.csic.es: Zaragoza-Trella et al (2020) Interactions among global change pressures act in a non-additive way on bumblebee individuals and colonies. Functional Ecol DOI 10.1111/1365-2435.13703


https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.13703