Under climate change, cold-adapted alpine ecosystems are turning into hotspots of warming. However, the complexity of driving forces of growth, associated biomass gain and carbon storage of alpine shrubs is poorly understood. We monitored alpine growth mechanisms of six common shrub species across contrasting biomes, Mediterranean and tundra, using 257 dendrometers, recording stem diameter variability at high temporal resolution. Linking shrub growth to on-site environmental conditions, we modelled intra-annual growth patterns based on distributed lag non-linear models implemented with generalized additive models. We found pronounced bimodal growth patterns across biomes, and counterintuitively, within the cold-adapted biome, moisture, and within the drought-adapted biome, temperature was crucial, with unexpected consequences. In a warmer world, the Mediterranean alpine might experience strong vegetation shifts, biomass gain and greening, while the alpine tundra might see less changes in vegetation patterns, minor modifications of biomass stocks and rather browning.

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Here, we present measurement data of stem diameter variability of three common woody plants, monitored in the Mediterranean-alpine biome for six consecutive years (2015–2020). These focal species (Astragalus granatensis, Cytisus galianoi, and Genista versicolor) are abundant across the Sierra Nevada mountain chain (Southern Spain) and will potentially be affected by severe future climatic changes predicted for the region, including increased aridification in a warming environment. Understanding their fine-scale radial growth-patterns in relation to local environmental parameters might gain further insights into future vegetational shifts. We therefore used 139 high-resolution dendrometers to continuously monitor specimens along a steep elevational gradient and at varying topographical positions within the heterogeneous topography of the region. Additionally, we measured on-site environmental conditions at each studied site, including soil moisture and soil temperature within the root zone. All data were recorded at hourly resolution and are presented as daily mean values. The dataset was collected as a part of our long-term alpine ecosystem research program (LTAER), which functions as the basis for our recent projects on the use of dendrometer data to better understand the physiological mechanisms and the environmental drivers of the ongoing alpine greening.

Forest degradation occurs in natural World Heritage Sites (WHS) in the Global South despite the implementation of various strategic policies and the World Heritage Convention (WHC) on forest protections of the sites and this poses challenges to improving natural heritage sustainability. The current study aims to investigate spatial determinants of forest degradation in the Kilimanjaro WHS, Tanzania, to support strategic policies for forest landscape protection and natural heritage sustainability. Using remotely sensed, Digital Elevation Model, and tourism location data, we performed the supervised classification of satellite images, Digital Elevation, Euclidean distance, and linear regression modeling to identify spatial determinants of forest degradation. Our key findings indicated that while spatial determinants vary with different locations, human (tourism) activities e.g., developments of campsites, picnics, tourist routes, the historical site, and attraction areas are associated with forest degradation in the southern parts of the site. In addition to human activities, natural factors such as low levels of elevation and degrees of slope are associated with forest degradation at the site. However, in the northwest and southwest of the site, high degrees of slope are associated with the degradation. Our findings showed that while bare land surface encroached the primary forest with about 2.88%, moorland vegetation encroached the primary forest with about 16.95%, indicating a large degradation of the primary forest with about 19.83% for the past four decades. The information provided in this study is crucial to support site managers and decision-makers in strategic policies and WHC implementations on forest protection for natural heritage sustainability.

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