Early spring warming may hasten leaf emergence in Erythronium americanum

Abstract

Premise Climate change is making spring arrive earlier than in the past, causing some species to alter the timing of their spring activities. This study addressed whether Erythronium americanum Ker Gawl. (trout lily), a common spring ephemeral, can emerge earlier if exposed to early spring warming. Methods I collected corms of Erythronium americanum in the fall, overwintered them in soil, and exposed them to warming in either mid (early treatment) or late (late treatment) February. The timing of leaf emergence was monitored and compared between treatments. Results Leaves exposed to early warming emerged earlier than those in the late treatment. Bud break happened closer to date of exposure to warming in the late treatment than in the early treatment. Conclusions Spring ephemerals may be able to produce leaves early in response to early spring warming induced by climate change. Risk of late frost and eventual shading by the canopy may limit the duration of a potentially extended growing season.

Once and future changes in climate and phenology within the Adirondack uplands (New York, USA)

“…These comparisons demonstrate that the records of terrestrial phenology at PSC reflect regionally coherent patterns that include strong sensitivity to spring temperatures and a scarcity of significant temporal trends in recent decades that reflects a short-term lack of climatic trends in late winter and early spring. The slopes of temperature-phenology relationships for the maples, trout lilies, and trillium generally increased from January to April, a pattern that is consistent with experimental evidence that sprouting dates for some forest plant species in the northeastern United States shift more in response to warming later in winter than earlier [44].…”

Severe frost but not shade could limit the future growing season of Erythronium americanum

“…Collectively, if E. americanum starts its growing season early as the climate warms (Ladwig et al, 2019;Tessier, 2019), it may suffer frost damage and potentially corm death from severe, late frosts in some years (Figure 2, Gu et al, 2008;Hufkens et al, 2012). This pattern may further drive the species into more sheltered and warmer microclimates in the forest (Beatty, 1984;Vanwalleghem and Meenemeyer, 2019;Zellweger et al, 2020), thereby reducing its abundance across gradients (Van Der Veken, Bossuyt and Hermy, 2004;Gracia et al, 2007).…”

“…Barring repeated and heavy late frost, E. americanum could experience an extended growing season with future climate warming. Early spring warmth causes plants of this species to break bud and emerge early (Tessier, 2019) and potentially early shade from canopy trees will not cause an advanced end to the growing season (Figure 1). This extension provides greater opportunity for photosynthesis under high light, spring conditions (Lapointe, 2001;Kato and Komiyama, 2002) and could lead to greater energy resources for reproduction, both vegetative and sexual (Muller, 1978;Weiner et al, 2009), pending risk of frost damage to reproductive structures (Thomson, 2010).…”

“…Vernal activity in E. americanum also makes this species important to nutrient cycling and retention (Muller, 1978;Lerat et al, 2002). When exposed to early warming, E. americanum can hasten its leaf out, suggesting that early spring warming could expand its growing season (Tessier, 2019). What is not clear is what ecological factors could limit the expansion of the growing season for E.…”

Bulb growth potential is independent of leaf longevity for the spring ephemeralErythronium americanumKer-Gawl

“…Warmer temperatures usually hasten leaf senescence and negatively affect growth. Leaf emergence of E. americanum can also be hastened under earlier snowmelt (Tessier, 2019). Climate change affects both snow cover duration and average spring temperature in Quebec, Canada (Brown, 2010; Vincent et al ., 2012).…”