Climatic drivers of Sphagnum species distributions

Abstract

Peat mosses (genus Sphagnum) dominate most Northern mires and show distinct distributional limits in Europe despite having efficient dispersal and few dispersal barriers. This pattern indicates that Sphagnum species distributions are strongly linked to climate. Sphagnum-dominated mires have been the largest terrestrial carbon sinks in Europe over the last few millennia. Understanding the climatic drivers of Sphagnum species distributions is important for predicting the future Climatic drivers of Sphagnum species distributions 2 functionality of peatlands. We used MaxEnt, with biologically relevant climatic variables, to model and clarify the current distributions of 45 Sphagnum species in Europe. We used a dataset of 238 316 records from across Europe (30° to 90° N, -30° to 63° E; Sahara to the Arctic, Azores to Ural mountains). We used annual degree-days, annual water balance and their monthly standard deviations (i.e. seasonality) as climatic predictors over a range of spatial resolutions (from 10 to 200 km pixel size). With these climatic predictors, we produced reasonably accurate projections of the distribution of 45 species (overall AUC >0.8). Large pixels (100 and 200 km) resulted in loss of detail, but smaller pixels (10-50 km) performed well across fit measurements. Projected distributions at the 50 × 50 km resolution showed the largest resemblance to published distribution maps. Suitable climate for many Sphagnum species was associated with the northern, western and mountainous parts of Europe. We found that annual water balance was an important indicator of Sphagnum presence. Limits in relation to annual water balance were the same as reported by bioclimatic peatland models from North America. Most Sphagnum species were limited to annual degree-days between -5000 °C y -1 and 5000 °C y -1 . Seasonality in both climate variables separated species, with degree-day seasonality having a stronger influence than water balance seasonality.High degree-day seasonality as a consequence of cold temperature sets a northern distribution limit to some species. The results suggest that the future of Sphagnum diversity in Europe is most strongly dependent on changes in water availability and in seasonal temperature variation. Highlights• Peat mosses (Sphagnum) form northern peatlands and species have different distributions across Europe.• We model the climatic suitability for all European species using multiple databases and MaxEnt models.• The climatic suitability for most species can be accurately modelled with mean annual temperature and water balance and their variation over the year.• Sphagnum has its highest species richness in northwestern Europe.• The magnitude of temperature fluctuations over the year is an important climatic variable that separates current species distributions.

Will climate change cause the global peatland to expand or contract? Evidence from the habitat shift pattern of Sphagnum mosses

“…Our results showed that all six species under current climatic scenarios were mainly distributed in North America and Eurasia. The areas with Sphagnum species richness greater than 2 were mainly concentrated in latitudes above 40°N in North America and above 45°N in Europe, which was consistent with the previous studies (Campbell et al, 2021; Gunnarsson, 2005; Oke & Hager, 2017). In addition, Sphagnum ‐dominated peatlands with a small range in the Southern Hemisphere were also realistically represented in this study, including the eastern coastal region of Australia and the southeastern coastal region of South America.…”

“…Changes in the geographic distribution and composition of species driven by climate change are closely linked to the fate of peatland ecosystems. Recent species distribution models (SDMs) for Sphagnum species or Sphagnum bogs have focused on suitable habitat projections on country‐wide and continental‐wide scales (Campbell et al, 2021; Cerrejón et al, 2020; Cong et al, 2020; Oke & Hager, 2017). Oke and Hager (2017) modeled the distribution and expansion of four Sphagnum species in North American peatlands which were tightly influenced by the future climate scenarios.…”

Ecological features of sphagnum mosses on the territory of Ukrainian Gorgany

“…Сфагнові мохи є одними з кріофітів, найбільш залежних від низки чинників, насамперед умов середовища: зволоження, рН, висоти над рівнем моря, типів оселищ, ступеня трансформації рослинного покриву унаслідок антропогенного впливу, в тому числі забруднення і рекреаційного навантаження, змін клімату тощо [20,23,[27][28][29][30]33]. За наявністю певних видів сфагнових мохів на болотах можна судити про ступінь трофності, тобто про абсолютне і відносне багатство болотних екотопів, яке визначається характером відкладень, ґрунтотвірними породами та багатством солей ґрунтових вод, які доступні рослинам [2, 31,33].…”

“…Як відомо з літературних даних, сфагни є хорошими індикаторами кислотності ґрунту, показниками зменшення вологості унаслідок зміни доступності води в екосистемах і сезонних коливань температури, що призводить до зменшення видового складу й обмеження поширення сфагнових мохів. Також викопні зразки сфагнових мохів у торфовищах використовують як індикатори минулих кліматичних змін [20,24,29].…”

“…Рід сфагнум приурочений до амфібіальних біотопів. Маючи пристосування до життя в такому середовищі, він чутливо реагує на зміни гідрологічного режиму [13,20,28,33]. Зважаючи на кардинальні зміни упродовж останнього століття, деякі види сфагнів могли зникнути або ж суттєво скоротити свій ареал в Українських Карпатах.…”