Plant traits: Their role in the regeneration of alpine plant communities in sub‐arctic Finland

Welling, Pirjo; Tolvanen, Anne; Laine, Kari

doi:10.1111/j.1654-1103.2005.tb02354.x

Cited by 17 publications

(3 citation statements)

References 41 publications

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“…Thus, supporting previous studies on typical seed traits surviving through the digestive system of a large herbivore (Janzen 1984, Myers et al 2004, Yamashiro and Yamashiro 2006). However, the small seed size found in this study could also reflect seed characteristics of the grazing environment (Bruun and Poschlod 2006), that is, in northern and alpine environments seed size is generally small (Welling et al 2005).…”

Section: Discussionmentioning

confidence: 70%

Endozoochory varies with ecological scale and context

Bråthen

González²,

Iversen³

et al. 2007

Ecography

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Several studies on endozoochory have established large herbivores as important for seed dispersal, yet no studies have evaluated how endozoochory is dependent on ecological scale and context. Here we address effects of reindeer density on endozoochory in a hierarchical, multi-scale study, encompassing several ecological contexts.We found reindeer density effects on endozoochory to vary with spatial scale. Higher reindeer densities at the level of landscape areas, as indexed through faeces abundance, were related to both less species and lower abundance of emerging plants from faeces. In contrast, there was no effect of higher reindeer densities at the level of herding districts (i.e. large scale assemblages of landscapes). Lack of consistency between scales reflects ecological hierarchy, indicating that reindeer density effects on endozoochory best matches at the scale of landscapes.Pasture plant composition was only partly an important ecological factor. That is, ericoid species, the dominating plants in the pastures, were also the most abundant seed plants emerging from the faeces. However, only a small proportion of herbaceous seed plant species found in the pastures were emerging from the faeces, and their emergences were positively related to the site fertility and altitude of the pasture.Studies addressing endozoochory of ruminants are typically concerned with seed plants. In this study we found indications of that also diaspores of ferns survive the digestive tract of large herbivores. Vascular spore plants were even more abundant in the faeces than were vascular seed plants.Results from this study demonstrate that reindeer may counteract a potentially negative impact on seed limitation from their grazing by returning viable seeds in their faeces. However, in Finnmark, northern Norway, this effect is only marginal, relates only to a very few species and individuals and shows ecological scale and context dependence.

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Section: Discussionmentioning

confidence: 70%

Endozoochory varies with ecological scale and context

Bråthen

González²,

Iversen³

et al. 2007

Ecography

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“…Most of them are able to germinate easily (Kibe & Masuzava 1994; Forbis ; Welling et al. ), ensuring an increase in plant population size (Marcante et al. ) and maintaining a high genetic diversity (Raffl et al.…”

Section: Discussionmentioning

confidence: 99%

“…), species establish only at low rates due to high seedling mortality (Welling et al. ; Erschbamer et al. ; Marcante et al.…”

Section: Introductionmentioning

confidence: 99%

Frost as a limiting factor for recruitment and establishment of early development stages in an alpine glacier foreland?

Marcante

Sierra-Almeida

Spindelböck

et al. 2012

J Vegetation Science

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Questions How frost resistant are the early development stages (seeds, seedlings, plantlets and juveniles) of alpine plant species? Do summer frosts impair establishment of plant species typical of different successional stages on a central alpine glacier foreland? Location Rotmoos glacier foreland, Austrian Central Alps (Obergurgl, Tyrol, Austria). Methods Seeds of 12 species typical of different successional stages were collected in the glacier foreland and either sown directly in the field or in a growth chamber (25/10 °C, 16/8 h) and grown to the investigated development stages. Frost resistance of the early development and adult stages was determined by exposing them to a set of freezing temperatures and assessing viability with the tetrazolium test (LT 50, i.e. 50% of samples being lethally frost damaged). Results Dry seeds had the highest frost resistance (LT 50: −19 °C), followed by wet seeds after imbibition (LT 50: −8 °C). With the onset of germination, frost resistance decreased rapidly. While germinated seeds tolerated a mean of −3.2 °C, seedlings and juveniles were less frost resistant (LT 50: −2.5 °C). Along the primary succession, seedlings of pioneer species were significantly less frost resistant than early‐ and late‐successional species. However, field grown seedlings, mainly of pioneer species, showed higher frost resistance (mean: −5 °C) than the growth chamber seedlings (mean: −3 °C), indicating that frost hardening (transition from a lower to a higher level of frost resistance) is already possible during these early stages of development. Conclusions The low frost resistance during and after germination may not suffice to survive summer frosts and may at least in certain years explain the high seedling mortality rates recognized in the glacier foreland.

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Heat tolerance of early developmental stages of glacier foreland species in the growth chamber and in the field

et al. 2014

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In glacier forelands, seeds readily germinate, however, a high proportion of seedlings die shortly after their appearance. We hypothesized that besides drought, frost and missing safe sites, heat on the ground surface could be one of the major threats for seedlings. The heat strain in different ground strata was assessed from 2007 to 2010. The heat tolerance (LT50) of eleven alpine species from different successional stages was tested considering imbibed (G1) and germinated seeds (G2) as well as seedlings (G3). Additionally, the heat hardening capacity of seedlings was determined in the field. Across all species, LT50 decreased significantly by 9 K from G1 (55 °C) to G3 (46 °C), similarly in all species of the successional stages. Field-grown seedlings had mostly an increased LT50 (2K). Intraspecifically, LT50 of seedlings varied between 40.6 and 52.5 °C. Along the chronosequence, LT50 in G1 was similar, but was higher in G2 and G3 of early successional species. The highest temperatures occurred at 0–0.5 cm in air (mean/absolute maximum: 42.6/54.1 °C) posing a significant heat injury risk for seedlings when under water shortage transpirational cooling is prevented. Below small stones (0–0.5 cm), maxima were 4 K lower, indicating heat safer microsites. Maxima >30 °C occurred at 32.3, >40 °C at 6.2 %. Interannually, 2010 was the hottest year with heat exceeding LT50 at all microsites (0–0.5 cm). Temperature maxima on sandy surfaces were lower than on microsites with gravel (diameter <5–10 mm). The hot summer of 2010 may be a small foretaste of in future more severe and frequent heat waves. Ground surface temperature maxima at the pioneer stage are already now critical for heat survival and may partly explain the high seedling mortality recognized on recently deglaciated terrain.Electronic supplementary materialThe online version of this article (doi:10.1007/s11258-014-0361-8) contains supplementary material, which is available to authorized users.

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Plant traits: Their role in the regeneration of alpine plant communities in sub‐arctic Finland

Cited by 17 publications

References 41 publications

Endozoochory varies with ecological scale and context

Endozoochory varies with ecological scale and context

Frost as a limiting factor for recruitment and establishment of early development stages in an alpine glacier foreland?

Heat tolerance of early developmental stages of glacier foreland species in the growth chamber and in the field

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