Climatic determinants of berry crops in the boreal forest of the southwestern Yukon

Abstract

Berry crops in the southwestern Yukon were quantified from 1997 to 2008 at 10 locations along 210 km of the Alaska and Haines highways. We tested the hypothesis that the size of berry crops could be predicted from spring and summer temperature and rainfall of years t, t–1 (1 year prior), and t–2 (2 years prior). Six common species were studied in the boreal forest of the Kluane region: Arctostaphylos rubra (Rehd. & Wils.) Fern., Arctostaphylos uva-ursi (L.) Spreng. s.l., Empetrum nigrum L., Vaccinium vitis-idaea L., Geocaulon lividum (Richards) Fern, and Shepherdia canadensis (L.) Nutt.. For the first five species we counted berries on fixed 40 cm × 40 cm quadrats to obtain an index of berry production for the Kluane region for each of the 12 years, and for S. canadensis we counted berries on two tagged branches of 10 bushes at each location. Stepwise multiple regressions were utilized to predict the size of berry crops for each species. For all species, predictive equations could explain statistically 80%–96% of the variation in berry crops. Different weather variables characterized each plant species, and there was no common weather regression that could explain the variation in berry crops in all species. Rainfall and temperature from years t–1 and t–2 were typically the significant predictors. There was no indication of a periodicity in berry production, and 43%–60% of the quadrats counted had large berry crops at one year intervals, while other quadrats never had a high crop during the study interval.

Effects of picking methods on the berry production of bilberry (Vaccinium myrtillus), lingonberry (V. vitis-idaea) and crowberry (Empetrum nigrum ssp. hermaphroditum) in Northern Finland

“…In this study, between year variation in berry production was similar in the control and picking treatments, suggesting that other than picking method determined the berry production. According to generally accepted view, the variation in wild berry yields result from climatic conditions, such as temperature, precipitation and frost injuries during different stages of berry production (Raatikainen and Vän-ninen 1988;Tolvanen 1997;Wallenius 1999;Selås 2000;Krebs et al 2009;Gerdol et al 2013). In this study, wild berry production was highest in 2010 compared to other years.…”

“…Contrary to bilberry, the number of berries of lingonberry and crowberry decreased year by year in this study. Different between year variation in berry production suggests that the response of berry yields to climatic variables may be species specific (Krebs et al 2009). Moreover, both current and previous year's climatic variables may affect the berry production of long-lived wild berry species (Raatikainen and Vänninen 1988;Wallenius 1999;Selås 2000;Krebs et al 2009).…”

Variability of Long-Term Cyclicity in the Population Dynamics of the Northern Red-Backed Vole (Myodes Rutilus (Pallas, 1779)

“…У популяций Аляски на цикличность влияет только динамика за-пасов корма. Причем обилие урожая ягод там обусловлено погодными условиями (комбинации месячной летней температуры и осадков) двух предыдущих лет (Krebs et al, 2009). Так что и здесь внешним синхрониза-тором ритмов предполагается, хотя и опо-средованно, ход климатических факторов.…”

Future changes in the supply of goods and services from natural ecosystems: prospects for the European north

“…Berry production may be stimulated by warmer climate, but habitat loss and species interactions may result in decline, making predictions uncertain (Table 1). Production of berries varies among years, and depends on the weather in the preceding years (Selås 2000, Krebs et al 2009). Also, some of the berry-producing dwarf shrubs are particularly sensitive to warm events in winter (Bokhorst et al 2009) but recovery from damage is common (Aerts 2010).…”