Effects of future climate change on birch abundance and their pollen load

Abstract

Climate change impacts on the structure and function of ecosystems will worsen public health issues like allergic diseases. Birch trees (Betula spp.) are important sources of aeroallergens in Central and Northern Europe. Birches are vulnerable to climate change as these trees are sensitive to increased temperatures and summer droughts. This study aims to examine the effect of climate change on airborne birch pollen concentrations in Central Europe using Bavaria in Southern Germany as a case study. Pollen data from 28 monitoring stations in Bavaria were used in this study, with time series of up 30 years long. An integrative approach was used to model airborne birch pollen concentrations taking into account drivers influencing birch tree abundance and birch pollen production and projections made according to different climate change and socioeconomic scenarios. Birch tree abundance is projected to decrease in parts of Bavaria at different rates, depending on the climate scenario, particularly in current centres of the species distribution. Climate change is expected to result in initial increases in pollen load but, due to the reduction in birch trees, the amount of airborne birch pollen will decrease at lower altitudes. Conversely, higher altitude areas will experience expansions in birch tree distribution and subsequent increases in airborne birch pollen in the future. Even considering restrictions for migration rates, increases in pollen load are likely in Southwestern areas, where positive trends have already been detected during the last three decades. Integrating models for the distribution and abundance of pollen sources and the drivers that control birch pollen production allowed us to model airborne birch pollen concentrations in the future. The magnitude of changes depends on location and climate change scenario.

Drivers of the release of the allergens Bet v 1 and Phl p 5 from birch and grass pollen

“…Our study shows that in the case of Betula, the importance of DOY on PAP is limited, probably due to less different species in the Betula genus in both Munich and Davos. The main tree species belonging to the genus Betula in the studied area are Betula pendula and Betula pubescens (Rojo et al, 2021), with B. pendula more abundant in this area of Europe (Beck et al, 2016).…”

Climate change and global health: A call to more research and more action

“…56 The major risk factor for hospitalization in the Melbourne event was allergic rhinitis (87%). 61 Recent studies have shown increased duration of pollen season, peak pollen concentration, total season pollen load, 62 and pollen allergenicity with climate change. 56 A recent study has found that climate change in North America contributes to about 50% of the lengthening pollen season.…”

Modeling past and future spatiotemporal distributions of airborne allergenic pollen across the contiguous United States

“…However, these impacts may be modulated by other, species-specific, factors that could offset or even reverse the predicted patterns ( 57 ). For instance, some tree species such as birch ( 58 ) and oak ( 59 ) could suffer the declining of their populations, as they are sensitive to increased temperatures and summer droughts. There have been observation-based studies conducted to explore taxa-specific effects for monitor locations at continental scale ( 21 , 23 ), while mechanistic process-based models used to analyze future pollen patterns for multiple taxa are absent ( 34 ).…”