Habitat‐specific responses in the flowering phenology and seed set of alpine plants to climate variation: implications for global‐change impacts

Abstract

Timing of snowmelt is a crucial factor determining the phenological schedule of alpine plants. A long-term monitoring of snowmelt regimes in a Japanese alpine revealed that snowmelt season has been accelerated during last 17 years in early snowmelt places, but such a trend has not been detected in late snowmelt places. This indicates that the warming effect on snowmelt pattern may be site specific. Flowering phenology of fellfield plants in an exposed wind-blown habitat was consistent between unusually warm year (1998) and normal year (2001). In contrast, flowering occurrence of snowbed plants varied greatly between the years depending on the snowmelt time.The number of flowering species in a fellfield community was large in the middle to late June and the middle to late July. Flowering of an early-melt snowbed community showed a peak in the middle of flowering season, and that of a late-melt snowbed community showed a peak in early flowering season. These habitat-specific phenological patterns were consistent between 1998 and 2001. Effects of the variation in flowering timing on seed-set success were evaluated for an entomophilous snowbed herb, Peucedanum multivittatum, along the snowmelt gradient during five years. When flowering occurred prior to early August, mean temperature during the flowering season positively influenced the seed set. When flowering occurred later than early August, however, plants enjoyed high seed-set success irrespective of temperature conditions if frost damage was absent. This is probably because the availability of pollinators depends not only on ambient temperature but also on seasonal progress. These results suggest that the effects of climate change on biological interaction may vary depending on habitat in the alpine ecosystem in which diverse snowmelt patterns create complicated seasonality for plants within a local area.

The effect of segregation of flowering time on fine-scale spatial genetic structure in an alpine-snowbed herb Primula cuneifolia

“…If heterogeneity in flowering time increased the mean level of inbreeding depression at the population level, natural selection might drive to accelerate flowering overlap among individuals. Although spatial pattern of snowmelt is relatively consistent, the rate of snowmelt progress highly fluctuates from year to year in this area (Kudo and Hirao, 2005). Therefore, the environmental fluctuation may overwhelm the selective force for flowering phenology.…”

“…P. cuneifolia has the following advantages. First, its rapid flowering after snowmelt and short flower longevity create a clear phenological sequence along a snowmelt gradient (Kudo, 1991(Kudo, , 1992Kudo and Hirao, 2005). Second, because of the heterostylous mating system like other Primula species (Richards, 2002), the effect of selfing on SGS is negligible.…”

Biological consequences of earlier snowmelt from desert dust deposition in alpine landscapes

“…Similarly, the onset of greening and flowering occur earlier in years when air temperatures warm and snow melts earlier (21)(22)(23).…”

Controls of seed quantity and quality on seedling recruitment of smith fir along altitudinal gradient in southeastern Tibetan Plateau

“…Seed bank can be balanced by germination, aging, death, or animal grazing (Kudo and Hirao 2006;Turner et al 2006;Wagner and Mitschunas 2008;Inouye 2008). The reasons why seed bank densities apparently higher at north-facing slope than at south-facing slope depended on lower soil temperature, close canopy and shade environment, and consequently leading to lower seed germination in north-facing slope.…”