Grassland allergenicity increases with urbanisation and plant invasions

Abstract

Pollen allergies have been on the rise in cities, where anthropogenic disturbances, warmer climate and introduced species are shaping novel urban ecosystems. Yet, the allergenic potential of these urban ecosystems, in particular spontaneous vegetation outside parks and gardens, remains poorly known. We quantified the allergenic properties of 56 dry grasslands along a double gradient of urbanisation and plant invasion in Berlin (Germany). 30% of grassland species were classified as allergenic, most of them being natives. Urbanisation was associated with an increase in abundance and diversity of pollen allergens, mainly driven by an increase in allergenic non-native plants. While not inherently more allergenic than native plants, the pool of non-natives contributed a larger biochemical diversity of allergens and flowered later than natives, creating a broader potential spectrum of allergy. Managing novel risks to urban public health will involve not only targeted action on allergenic non-natives, but also policies at the habitat scale favouring plant community assembly of a diverse, low-allergenicity vegetation. Similar approaches could be easily replicated in other cities to provide a broad quantification and mapping of urban allergy risks and drivers.

Immunologic, genetic, and ecological interplay of factors involved in allergic diseases

“…While allergen avoidance initially persisted as the primary prevention strategy for allergic diseases, recent findings have suggested the opposite—repeated exposure to allergen can lead to attenuation and possibly eradication of severe disease symptoms. To address the ecological aspect of allergic disease incidence, urban ecosystems must be designed to maximize biodiversity of native, non-allergenic vegetation and grassland species ( 81 ). Seasonal variations due to geographic differences must also be considered in the implementation therapeutic strategies ( 125 ).…”

Environmental degradation and the increasing burden of allergic disease: The need to determine the impact of nitrogen pollution

“…It has been hypothesized before that changes in plant community composition and primary productivity may affect airborne pollen distributions and abundances with subsequent potential knock-on effects for pollen allergy patients ( 60 , 62 ). However, to our knowledge, changes in plant community composition and productivity driven by environmental nitrogen pollution remain to be linked with changes in the severity of pollen allergy.…”

The phenological response of European vegetation to urbanisation is mediated by macrobioclimatic factors

“…Plant phenology is a crucial component of ecosystem functioning because of its role in the carbon cycle (Piao et al, 2023), feedbacks on local and regional climate (Richardson et al, 2013) and the assembly of ecological communities (Inouye, 2022; Renner and Zohner, 2018). It also has important repercussions from the point of view of public-health as is the case of the flowering phenology of species with high allergenic potential (Bernard-Verdier et al, 2022; Rojo et al, 2021). Plant phenology is sensitive to nutrient and water availability and changes in temperature and photoperiod (Piao et al, 2023); accordingly, over the last decades scientists have been making great efforts to quantify phenological changes in response to the multiple components of global change and to understand their consequences on ecosystems (Garcia et al, 2014; Menzel et al, 2020).…”