Effects of ambient climate and three warming treatments on fruit production in an alpine, subarctic meadow community.

Juha M Alatalo,Abdel‐Salam G Abdel‐Salam,Mohammad D Mollazehi,Rajiv Pandey,Ulf Molau,Annika K Jägerbrand,Junhu Dai

doi:10.1002/ajb2.1631

Abstract

PremiseClimate change is having major impacts on alpine and arctic regions, and inter‐annual variations in temperature are likely to increase. How increased climate variability will impact plant reproduction is unclear.MethodsIn a 4‐year study on fruit production by an alpine plant community in northern Sweden, we applied three warming regimes: (1) a static level of warming with open‐top chambers (OTC), (2) press warming, a yearly stepwise increase in warming, and (3) pulse warming, a single‐year pulse event of higher warming. We analyzed the relationship between fruit production and monthly temperatures during the budding period, fruiting period, and whole fruit production period and the effect of winter and summer precipitation on fruit production.ResultsYear and treatment had a significant effect on total fruit production by evergreen shrubs, Cassiope tetragona, and Dryas octopetala, with large variations between treatments and years. Year, but not treatment, had a significant effect on deciduous shrubs and graminoids, both of which increased fruit production over the 4 years, while forbs were negatively affected by the press warming, but not by year. Fruit production was influenced by ambient temperature during the previous‐year budding period, current‐year fruiting period, and whole fruit production period. Minimum and average temperatures were more important than maximum temperature. In general, fruit production was negatively correlated with increased precipitation.ConclusionsThese results indicate that predicted increased climate variability and increased precipitation due to climate change may affect plant reproductive output and long‐term community dynamics in alpine meadow communities.

Highlights

PREMISE: Climate change is having major impacts on alpine and arctic regions, and inter- annual variations in temperature are likely to increase
Year and treatment had a significant effect on total fruit production by evergreen shrubs, Cassiope tetragona, and Dryas octopetala, with large variations between treatments and years
Regarding the question of whether responses differed to static warming and the press and pulse treatments, we found that for total fruit production, there was no significant difference between open-top chambers (OTC) and pulse warming

Summary

Methods

In a 4-year study on fruit production by an alpine plant community in northern Sweden, we applied three warming regimes: (1) a static level of warming with open-t op chambers (OTC), (2) press warming, a yearly stepwise increase in warming, and (3) pulse warming, a single-year pulse event of higher warming. We analyzed the relationship between fruit production and monthly temperatures during the budding period, fruiting period, and whole fruit production period and the effect of winter and summer precipitation on fruit production. The alpine valley is situated above the treeline and covered with snow for most of the year, and the climate is classified as subarctic, with cool summers, relatively mild, snow-r ich winters (annual minimum temperature ranging from −27.3 to −21.7°C) and mean annual temperature of −2.0 to −2.7°C (1993–1999). Annual precipitation ranges from 605 mm (1996) to 990 mm (1993), with a mean for 1990–1999 of 808 mm. Is the warmest month, with mean monthly temperature from +5.4°C (1992) to +9.9°C (1997). The vegetation in the valley comprises a wide range of communities, varying from dry to wet and poor and acidic to base-rich. The geographical situation is subarctic-alpine, the vegetation of the area is representative of the Low Arctic, with Cassiope tetragona (Ericaceae), Dryas octopetala (Rosaceae), and Carex bigelowii (Cyperaceae) among the dominant species (Alatalo et al, 2016)

Results

Discussion

Conclusion