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Microrefugia: Not for everyone.

Hylander K, Ehrlén J, Luoto M, Meineri E - Ambio (2015)

Bottom Line: Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia.We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion).Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden, kristoffer.hylander@su.se.

ABSTRACT
Microrefugia are sites that support populations of species when their ranges contract during unfavorable climate episodes. Here, we review and discuss two aspects relevant for microrefugia. First, distributions of different species are influenced by different climatic variables. Second, climatic variables differ in the degree of local decoupling from the regional climate. Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia. We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion). Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

No MeSH data available.


Variation in growing degree-days and minimum temperature across a latitudinal gradient in Sweden represented by two regions: in south (Mälardalen) and in north (central Norrland). Data are from one year from the SMHI stations. a The two regions in Sweden, b a trendline superimposed on the full data and boxes showing differences in the overlap between the two variables
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Fig2: Variation in growing degree-days and minimum temperature across a latitudinal gradient in Sweden represented by two regions: in south (Mälardalen) and in north (central Norrland). Data are from one year from the SMHI stations. a The two regions in Sweden, b a trendline superimposed on the full data and boxes showing differences in the overlap between the two variables

Mentions: Variation in many climatic variables can be large in a topographic heterogeneous landscape, which corresponds to considerable latitudinal distances in flat landscapes (Scherrer and Körner 2011; Lenoir et al. 2013). For example, a difference in mean soil temperature of 7.2 °C was recorded among microsites during the growing season within a 2-km2 area in the Alps (Scherrer and Körner 2011). However, it is likely that different climatic variables differ with regards to how well they can be “reproduced” in landscapes at different latitudes (or altitudes). In other words, different climatic variables will differ concerning how strongly local conditions are determined by the regional mean. To examine this in more detail, we used temperature data from 54 weather stations collected by the Swedish Meteorological and Hydrological Institute (SMHI). We extracted hourly temperature data from a twelve-month period (June 2010–May 2011) from weather stations in southern and northern Sweden (Fig. 2a). From these data, we calculated two variables: the 5 % percentile minimum temperature (hereafter minimum temperature) and growing degree-days (base 5 °C, hereafter GDD). It is obvious that over the whole gradient there is a clear correlation between these variables with higher coldest temperature in areas with high GDD (Fig. 2b). However, it is also clear that there is much more overlap in minimum temperatures between the regions than for GDD (Fig. 2b). According to our reasoning and these data, this would imply that species limited by GDD toward the north might have had more difficulty in finding localities with suitable conditions in microrefugia in northern Sweden during the last cooling period after the warm peak 5000 years ago, than species limited by minimum temperatures. The data used for this example are from weather stations, which are located at sites selected to well represent regional averages. If variation in micro-climate across a landscape had been based on random sites or stratified to capture extremes along e.g., topographic gradients, the variation in both variables would probably have been much larger in both of the regions. Thus, to assess the case illustrated in Fig. 2 in more detail would need additional data sampled at a much finer resolution and sampling covering a broad range of small-scale habitat variation.Fig. 2


Microrefugia: Not for everyone.

Hylander K, Ehrlén J, Luoto M, Meineri E - Ambio (2015)

Variation in growing degree-days and minimum temperature across a latitudinal gradient in Sweden represented by two regions: in south (Mälardalen) and in north (central Norrland). Data are from one year from the SMHI stations. a The two regions in Sweden, b a trendline superimposed on the full data and boxes showing differences in the overlap between the two variables
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4289006&req=5

Fig2: Variation in growing degree-days and minimum temperature across a latitudinal gradient in Sweden represented by two regions: in south (Mälardalen) and in north (central Norrland). Data are from one year from the SMHI stations. a The two regions in Sweden, b a trendline superimposed on the full data and boxes showing differences in the overlap between the two variables
Mentions: Variation in many climatic variables can be large in a topographic heterogeneous landscape, which corresponds to considerable latitudinal distances in flat landscapes (Scherrer and Körner 2011; Lenoir et al. 2013). For example, a difference in mean soil temperature of 7.2 °C was recorded among microsites during the growing season within a 2-km2 area in the Alps (Scherrer and Körner 2011). However, it is likely that different climatic variables differ with regards to how well they can be “reproduced” in landscapes at different latitudes (or altitudes). In other words, different climatic variables will differ concerning how strongly local conditions are determined by the regional mean. To examine this in more detail, we used temperature data from 54 weather stations collected by the Swedish Meteorological and Hydrological Institute (SMHI). We extracted hourly temperature data from a twelve-month period (June 2010–May 2011) from weather stations in southern and northern Sweden (Fig. 2a). From these data, we calculated two variables: the 5 % percentile minimum temperature (hereafter minimum temperature) and growing degree-days (base 5 °C, hereafter GDD). It is obvious that over the whole gradient there is a clear correlation between these variables with higher coldest temperature in areas with high GDD (Fig. 2b). However, it is also clear that there is much more overlap in minimum temperatures between the regions than for GDD (Fig. 2b). According to our reasoning and these data, this would imply that species limited by GDD toward the north might have had more difficulty in finding localities with suitable conditions in microrefugia in northern Sweden during the last cooling period after the warm peak 5000 years ago, than species limited by minimum temperatures. The data used for this example are from weather stations, which are located at sites selected to well represent regional averages. If variation in micro-climate across a landscape had been based on random sites or stratified to capture extremes along e.g., topographic gradients, the variation in both variables would probably have been much larger in both of the regions. Thus, to assess the case illustrated in Fig. 2 in more detail would need additional data sampled at a much finer resolution and sampling covering a broad range of small-scale habitat variation.Fig. 2

Bottom Line: Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia.We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion).Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

View Article: PubMed Central - PubMed

Affiliation: Department of Ecology, Environment and Plant Sciences, Stockholm University, 106 91, Stockholm, Sweden, kristoffer.hylander@su.se.

ABSTRACT
Microrefugia are sites that support populations of species when their ranges contract during unfavorable climate episodes. Here, we review and discuss two aspects relevant for microrefugia. First, distributions of different species are influenced by different climatic variables. Second, climatic variables differ in the degree of local decoupling from the regional climate. Based on this, we suggest that only species limited by climatic conditions decoupled from the regional climate can benefit from microrefugia. We argue that this restriction has received little attention in spite of its importance for microrefugia as a mechanism for species resilience (the survival of unfavorable episodes and subsequent range expansion). Presence of microrefugia will depend on both the responses of individual species to local climatic variation and how climate-forcing factors shape the correlation between local and regional climate across space and time.

No MeSH data available.