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- Merinero, Sonia, et al.
(author)
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Intraspecific variation influences performance of moss transplants along microclimate gradients
- 2020
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In: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 101:5
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Journal article (peer-reviewed)abstract
- Identifying the environmental drivers of population dynamics is crucial to predict changes in species abundances and distributions under climate change. Populations of the same species might differ in their responses as a result of intraspecific variation. Yet the importance of such differences remains largely unexplored. We examined the responses of latitudinally distant populations of the forest moss Hylocomiastrum umbratum along microclimate gradients in Sweden. We transplanted moss mats from southern and northern populations to 30 sites with contrasting microclimates (i.e., replicated field common gardens) within a forest landscape, and recorded growth and survival of individual shoots over 3 yr. To evaluate the importance of intraspecific variation in responses to environmental factors, we assessed effects of the interactions between population origin and microclimate drivers on growth and survival. Effects on overall performance of transplanted populations were estimated using the product of survival and growth. We found differences between southern and northern populations in the response to summer temperature and snowmelt date in one of three yearly transitions. In this year, southern populations performed better in warm, southern-like conditions than in cold, northern-like conditions; and the reverse pattern was true for northern populations. Survival of all populations decreased with evaporation, consistent with the high hydric demands and poikilohydric nature of mosses. Our results are consistent with population adaptation to local climate, and suggest that intraspecific variation among populations can have important effects on the response of species to microclimate drivers. These findings highlight the need to account for differential responses in predictions of species abundance and distribution under climate change.
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| 2. |
- Römer, Gesa, et al.
(author)
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Drivers of large-scale spatial demographic variation in a perennial plant
- 2021
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In: Ecosphere. - : Wiley. - 2150-8925 .- 2150-8925. ; 12:1
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Journal article (peer-reviewed)abstract
- To understand how the environment drives spatial variation in population dynamics, we need to assess the effects of a large number of potential drivers on vital rates (survival, growth, and reproduction) and explore these relationships over large geographical areas and broad environmental gradients. In this study, we examined the effects of a wide variety of abiotic and biotic environmental factors on the demography of the forest understory herb Actaea spicata between 2017 and 2019 at 40 sites across Sweden, including the northern range margin of its distribution. We assessed the effects of potential environmental drivers on vital rates using generalized linear mixed models (GLMMs) and then quantified the impact of each important driver on population growth rate (λ) using integral projection models (IPMs). Population dynamics of A. spicata were mostly driven by environmental factors affecting survival and growth, such as air humidity, soil depth, and forest tree species composition, and thus, those drivers jointly determined the realized niche of the species. Soil pH had a strong effect on the flowering probability, while the effect on λ was relatively small. In addition to identifying specific drivers for A. spicata’s population dynamics, our study illustrates the impact that spatial variation in environmental conditions can have on λ. Assessing the effects of a broad range of potential drivers, as done in this study, is important not only to quantify the relative importance of different drivers for population dynamics but also to understand species distributions and abundance patterns.
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| 3. |
- Greiser, Caroline, et al.
(author)
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Warm range margin of boreal bryophytes and lichens not directly limited by temperatures
- 2021
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In: Journal of Ecology. - : Wiley. - 0022-0477 .- 1365-2745. ; 109:10, s. 3724-3736
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Journal article (peer-reviewed)abstract
- Species at their warm range margin are potentially threatened by higher temperatures, but may persist in microrefugia. Whether such microsites occur due to more suitable microclimate or due to lower biotic pressure from, for example competitive species, is still not fully resolved. We examined whether boreal bryophytes and lichens show signs of direct climate limitation, that is whether they perform better in cold and/or humid microclimates at their warm range margin. We transplanted a moss, a liverwort and a lichen to 58 boreal forest sites with different microclimates at the species' southern range margin in central Sweden. Species were grown in garden soil patches to control the effects of competitive exclusion and soil quality. We followed the transplanted species over three growing seasons (2016-2018) and modelled growth and vitality for each species as a function of subcanopy temperature, soil moisture, air humidity and forest type. In 2018, we also recorded the cover of other plants having recolonized the garden soil patches and modelled this potential future competition with the same environmental variables plus litter. Species performance increased with warmer temperatures, which was often conditional on high soil moisture, and at sites with more conifers. Soil moisture had a positive effect, especially on the moss in the last year 2018, when the growing season was exceptionally hot and dry. The lichen was mostly affected by gastropod grazing. Recolonization of other plants was also faster at warmer and moister sites. The results indicate that competition, herbivory, shading leaf litter and water scarcity might be more important than the direct effects of temperature for performance at the species' warm range margin. Synthesis. In a transplant experiment with three boreal understorey species, we did not find signs of direct temperature limitation towards the south. Forest microrefugia, that is habitats where these species could persist regional warming, may instead be sites with fewer competitors and enemies, and with sufficient moisture and more conifers in the overstorey.
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