• Energy Research

The 11th Conference of the Spanish Association of Terrestrial Ecology, held in Pamplona, Spain, on 6-10 May 2013, included a symposium on alpine ecological research in the Iberian Peninsula. This session offered an excellent opportunity to assess the state and progress of alpine ecology in this region, identify knowledge gaps, and discuss further directions for research. Iberian alpine ecosystems are biodiversity hotspots and have traditionally contributed to sustaining rural livelihoods. Today, these ecosystems are subjected to large changes in land uses, including land abandonment, and are affected by climate change. This article reviews the current state of Iberian alpine ecology and proposes a research agenda. Alpine ecology in the Iberian Peninsula is a growing field of research. The need for larger spatial and temporal scales in research and monitoring, along with the integration of socioecological aspects, is a critical issue for understanding the major drivers of change in the alpine ecosystems of the Iberian Peninsula. The implementation of effective mitigation strategies aimed at reducing the impact of the pressing environmental and socioeconomic problems of Iberian mountain areas can only be accomplished through a multidisciplinary and integrative approach.

Drought stress is an alarming constraint to plant growth, development, and productivity worldwide. However, plant-associated bacteria, fungi, and viruses can enhance stress resistance and cope with the negative impacts of drought through the induction of various mechanisms, which involve plant biochemical and physiological changes. These mechanisms include osmotic adjustment, antioxidant enzyme enhancement, modification in phytohormonal levels, biofilm production, increased water and nutrient uptake as well as increased gas exchange and water use efficiency. Production of microbial volatile organic compounds (mVOCs) and induction of stress-responsive genes by microbes also play a crucial role in the acquisition of drought tolerance. This review offers a unique exploration of the role of plant-associated microorganisms—plant growth promoting rhizobacteria and mycorrhizae, viruses, and their interactions—in the plant microbiome (or phytobiome) as a whole and their modes of action that mitigate plant drought stress.

Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6--7% over the current levels with a 1 textdegreeC increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.