Short-lived species move uphill faster under climate change

Climate change is pushing species ranges and abundances towards the poles and mountain tops. Although many studies have documented local altitudinal shifts, knowledge of general patterns at a large spatial scale, such as a whole mountain range, is scarce. From a conservation perspective, studying altitudinal shifts in wildlife is relevant because mountain regions often represent biodiversity hotspots and are among the most vulnerable ecosystems. Here, we examine whether altitudinal shifts in birds’ abundances have occurred in the Scandinavian mountains over 13 years, and assess whether such shifts are related to species’ traits. Using abundance data, we show a clear pattern of uphill shift in the mean altitude of bird abundance across the Scandinavian mountains, with an average speed of 0.9 m per year. Out of 76 species, 7 shifted significantly their abundance uphill. Altitudinal shift was strongly related to species’ longevity: short-lived species showed more pronounced uphill shifts in abundance than long-lived species. The observed abundance shifts suggest that uphill shifts are not only driven by a small number of individuals at the range boundaries, but the overall bird abundances are on the move. Overall, the results underscore the wide-ranging impact of climate change and the potential vulnerability of species with slow life histories, as they appear less able to timely respond to rapidly changing climatic conditions.

A deeper insight into the dynamics and effects of the Hiccup of the fall transition

<p>In autumn the prevailing wind in the middle atmosphere at mid and high latitudes changes from summer easterly to winter westerly.  This process is not smooth but interrupted by the Hiccup of the fall transition with characteristics similar to a mini sudden stratospheric warming (SSW) which occurs in fall even though the zonal mean zonal wind does not reverse to easterly again. Combining global reanalysis data and satellite observations we improve our knowledge and understanding of the dynamics of the Hiccup of the fall transition in the middle atmosphere. The introduction of a new definition for the onset of the Hiccup focusing now on its core region in the lower mesosphere allows us the automatic detection of a Hiccup in almost every year and thus a deeper insight into its dynamics. For example, we found a latitudinal and altitudinal shift in the zonal wind regime during the Hiccup. We also investigate its 3D-structure and compare the characteristics of the Hiccup in the Northern hemisphere with those in the Southern hemisphere. We found that the latitudinal and altitudinal shift of the zonal wind regime occurs in both hemispheres but is more pronounced in the Northern hemisphere and smoother in the Southern hemisphere.  Additionally, we discuss the possible impact of the Hiccup on the D-region.</p>

Lean Pattern in an Altitude Range Shift of a Tree Species: Abies pinsapo Boiss.

Organisms modify their geographical distributions in response to changes in environmental conditions, or modify their affinity to such conditions, to avoid extinction. This study explored the altitudinal shift of Abies pinsapo Boiss. in the Baetic System. We analysed the potential distribution of the realised and reproductive niches of A. pinsapo populations in the Ronda Mountains (Southern Spain) by using species distribution models (SDMs) for two life stages within the current populations. Then, we calculated the species’ potential altitudinal shifts and identified the areas in which the processes of persistence and migration predominated. The realised and reproductive niches of A. pinsapo are different to one another, which may indicate a displacement in its altitudinal distribution owing to changes in the climatic conditions of the Ronda Mountains. The most unfavourable conditions for the species indicate a trailing edge (~110 m) at the lower limit of its distribution and a leading edge (~55 m) at the upper limit. Even though the differences in the altitudinal shifts between the trailing and leading edges will not cause the populations to become extinct in the short term, they may threaten their viability if the conditions that are producing the contraction at the lower limit persist in the long term.

Global warming, slope stability, and the dynamization of geological hazards in high mountain regions: a case study from the Eastern Alps.

<p>In recent decades, slope instability in high-mountain regions has often been linked to the increase in temperature and the associated permafrost degradation and/or the increase in frequency/intensity of rainstorm events. In this context we analyzed the spatiotemporal evolution and potential controlling mechanisms of small to medium-size rockfalls and debris flows in a small catchment of the Italian Alps (Sulden/Solda basin). We found that rockfall events have been increasing since the 1990s, whereas debris flows have increased only since 2010. The current warming trend of mountain regions such as the Southern Alps is leading to an increased elevation of rockfall detachment areas (altitudinal shift of ca. 300-400 m in the study site), mostly controlled by frost-cracking and permafrost thawing. In contrast, the occurrence of debris flows does not exhibit such an altitudinal shift, as it is primarily driven by extreme precipitation events exceeding the 75th percentile of the intensity-duration rainfall distribution. The possible occurrence of a debris-flow event in this environment may be additionally influenced by the accumulation of unconsolidated debris over time, which is then released during extreme rainfall events. Overall, there is evidence that the upper Sulden basin (above ca. 2500 m asl), and especially the areas in the proximity of glaciers, have experienced a significant decrease in slope stability since the 1990s and that an increase in rockfalls and debris flows during spring and summer can be observed. Our study thus confirms that “forward-looking” hazard mapping should be undertaken in these increasingly frequented areas of the Alps, as these environmental changes have elevated the overall hazard level in these high-elevation regions.</p>

Humboldt’sTableau Physiquerevisited

Alexander von Humboldt’sTableau Physique(1807) has been one of the most influential diagrams in the history of environmental sciences. In particular, detailed observations of the altitudinal distribution of plant species in the equatorial Andes, depicted on a cross-section of Mt. Chimborazo, allowed Humboldt to establish the concept of vegetation belt, thereby laying the foundations of biogeography. Surprisingly, Humboldt’s original data have never been critically revisited, probably due to the difficulty of gathering and interpreting dispersed archives. By unearthing and analyzing overlooked historical documents, we show that the top section of theTableau Physique, above the tree line, is an intuitive construct based on unverified and therefore partly false field data that Humboldt constantly tried to revise in subsequent publications. This finding has implications for the documentation of climate change effects in the tropical Andes. We found that Humboldt’s primary plant data above tree line were mostly collected on Mt. Antisana, not Chimborazo, which allows a comparison with current records. Our resurvey at Mt. Antisana revealed a 215- to 266-m altitudinal shift over 215 y. This estimate is about twice lower than previous estimates for the region but is consistent with the 10- to 12-m/decade upslope range shift observed worldwide. Our results show the cautious approach needed to interpret historical data and to use them as a resource for documenting environmental changes. They also profoundly renew our understanding of Humboldt’s scientific thinking, methods, and modern relevance.

Altitudinal Shift of Tetrao urogallus in an Alpine Natura 2000 Site: Implications for Habitat Restoration

Capercaillie (Tetrao urogallus L.), a territorial galliform species, is known to prefer mature conifer stands with canopy gaps and a vigorous understory of ericaceous species. Capercaillie is a useful umbrella species that has recently shown declining population trends and distribution changes in its southern geographic range. We aim to identify and assess the possible changes in summer capercaillie habitat selection between 2001 and 2011 in the Scanuppia Natura 2000 site (south-eastern Alps). The area is dominated by spruce (Picea abies (L.) Karsten) forests, followed by mixed forests, scrub, and open habitats. In both years, summer presence–absence of capercaillie was verified through the detection of droppings over 10 m radius circular plots located along contour lines (1500–1800 m). A set of environmental and habitat features was also surveyed. While overall population numbers remain unchanged over the surveyed period, results have shown an altitudinal shift in capercaillie distribution. Habitat variables had a stronger effect on the presence of capercaillie in 2001 than in 2011. Land cover and climate change are likely among the drivers of the shift in altitudinal distribution. This confirms the relevance of habitat restoration actions and to monitor changes in factors explaining capercaillie habitat selection.