Shifting phenology and abundance under experimental warming alters trophic relationships and plant reproductive capacity

Abstract

Abstract. Phenological mismatches due to climate change may have important ecological consequences. In a three-year study, phenological shifts due to experimental warming markedly altered trophic relationships between plants and insect herbivores, causing a dramatic decline of reproductive capacity for one of the plant species. In a Tibetan meadow, the gentian (Gentiana formosa) typically flowers after the peak larva density of a noctuid moth (Melanchra pisi ) that primarily feeds on a dominant forb (anemone, Anemone trullifolia var. linearis). However, artificial warming of ;1.58C advanced gentian flower phenology and anemone vegetative phenology by a week, but delayed moth larvae emergence by two weeks. The warming increased larval density 10-fold, but decreased anemone density by 30%. The phenological and density shifts under warmed conditions resulted in the insect larvae feeding substantially on the gentian flowers and ovules; there was ;100-fold more damage in warmed than in unwarmed chambers. This radically increased trophic connection reduced gentian plant reproduction and likely contributed to its reduced abundance in the warmed chambers.

Difference in Floral Traits, Pollination, and Reproductive Success between White and Blue Flowers ofGentiana leucomelaena(Gentianaceae) in an Alpine Meadow

“…The mean annual precipitation is 690mm, 80% of which occurs in the growing season between May and October for most of the plant species in the study site. The mean annual temperature is 0.9 °C, with maximum and minimum monthly means of 10.9 °C and -10.3 °C in July and January, respectively (Liu et al, 2011 ).…”

Climate warming alters nitrogen dynamics and total non-structural carbohydrate accumulations of perennial herbs of distinctive functional groups during the plant senescence in autumn in an alpine meadow of the Tibetan Plateau, China

“…The average annual precipitation is about 690 mm with 80% of occurring during the growing season (May to August) and fluctuating greatly among years. The annual mean period of snow cover is 76 days (Liu et al, 2011). The soil in this area is characterized by alpine meadow soil (Chinese classification), which corresponds to Cryumbrept following the US Soil Taxonomy.…”

Climate change effects on vegetation in the Pacific Northwest: a review and synthesis of the scientific literature and simulation model projections

“…Although earlier fl owering can promote increased seed production and viability (Richardson et al 2005, Walck et al 2011, it can also expose plants to frost damage and reduced seed production, particularly at high elevations and latitudes (Beaubien andHamann 2011, Inouye 2008). Climate-induced shifts in reproductive phenology can also alter plant reproductive capacity by altering phenological synchrony between plants and insect pollinators or herbivores (Hegland et al 2009, Liu et al 2011. Studies of seed masting in trees suggest that temperature and precipitation (water availability) may act at different stages of fl owering and fruiting to infl uence seed production (Selås et al 2002, Woodward et al 1994.…”

“…Plants and insect herbivores can both alter the timing of their growth stages based on environmental cues, but the cues used are not necessarily identical (Rathcke and Lacey 1985). Differing phenological responses to changing temperature and precipitation patterns could therefore alter plant-herbivore and insect-host interactions by increasing or reducing synchrony in life stage development (Harrington et al 1999, Liu et al 2011, Parmesan 2007. Inouye et al (2000) observed a changing relationship over 25 years between snowmelt and fl owering in alpine meadows (which was variable, but stable) and progressively earlier emergence of yellow-bellied marmots (Marmota fl aviventris), apparently caused by warming air temperatures, which produced progressively longer periods of food shortages for the marmots prior to snowmelt.…”