The effect of climate on masting in the European larch and on its specific seed predators

Abstract

Masting is the intermittent production of large seed crops by a population of plants. Two main hypotheses have been proposed to explain masting. Variations in seed crop may result from stochastic climate factors (temperature, rainfall, etc.), and/or masting may be a plant evolutionary strategy to avoid specific seed predators. To determine the effect of climate on the annual pattern of cone production in the European larch (Larix decidua), we analyzed larch cone production from 1975 to 2005 at 20 sites in the French Alps, ranging from 1,300 to 2,100 m a.s.l. (on average 17 years per site were sampled). We examined the effects of mast seeding on the predation of larch cones by the dominant specific pre-dispersal seed predators, cone fly Strobilomyia spp. Larch cone production varied across the years and was spatially synchronized throughout the region. We constructed two models to explain seed production, one for sites at low (<1,800 m) and one for sites at high (> or =1,800 m) altitudes, using partial least squares (PLS) regressions to detect across a large number of climate indices (306) the factors which best explain cone production. Monthly indices were more accurate descriptors than 4-month period indices. The predation rate was lower in high cone production years that followed low production years, supporting the predator satiation hypothesis. However, variable cone production explained only a small part of predation rates (45 and 25% at low and high altitudes, respectively). Predation was also directly affected by climate conditions. PLS regressions taking into account both cone production and climate factors accounted for as much as 68 and 82% of the predation rate variation at low and high altitudes, respectively. This study contributes to a better understanding of how climate factors differently affect the members of an interacting community.

Reproductive biology of Abies cephalonica Loudon in Mount Aenos National Park, Cephalonia, Greece

“…This phenomenon has been reported for many tree and shrub species and a variety of ecosystems (Herrera et al 1998;Koenig and Knops 2000;Schauber et al 2002;Suzuki et al 2005;Lázaro et al 2006;Poncet et al 2009). Many studies have shown that masting is caused by an interaction between abiotic and biotic factors (Mduma et al 2007).…”

‘Climatic factors control rodent seed predation in Pinus pinea L. stands in Central Spain’

“…This supports the predator satiation hypothesis (Janzen 1974;Salisbury 1942), which is expected in low diversity plant communities where masting occurs (Nilsson and Wastljung 1987;Homma et al 1999) and where predation predominates over animal-mediated dispersal (Hulme and Hunt 1999;Vander Wall 2002), as is clearly the case in our study. A predator control based on these two mechanisms has been identified in alpine ecosystems, enhancing fitness in European larch (Poncet et al 2009), which suggests that the described pattern may be common, at least in limiting environments. In the case of P. pinea, the 'safe' period resulting from this strategy and the time where germination is possible (early fall) overlap (Manso et al 2013a, b).…”

Impact of land use intensity and temperature on the reproductive performance of Dactylis glomerata populations in the southeastern Alps

“…Several studies have demonstrated different aspects of inter-population variation in seed production and seed mass, including climatic factors (Murray et al 2004;Poncet et al 2009), altitudinal gradients (Totland and Birks 1996;Pluess et al 2005), latitudinal variation (Winn and Gross 1993;Garcia et al 2000;Moles and Westoby 2003;Murray et al 2004;Moles et al 2007;De Frenne et al 2009), soil fertility (Wolfe 1995;Tungate et al 2002) and differences in habitat type (Endels et al 2004;Goulart et al 2006).…”