Fire history and weather interact to determine extent and synchrony of mast-seeding in rhizomatous scrub oaks of Florida

Abstract

In disturbance-prone ecosystems, fitness consequences of plant reproductive strategies are often determined by the relative timing of seed production and disturbance events, but the role of disturbances as proximate drivers of seed production has been overlooked. We use long-term data on seed production in Quercus chapmanii , Q. geminata and Q. inopina , rhizomatous oaks found in south central Florida's oak scrub, to investigate the role of fire history and its interaction with weather in shaping acorn production and its synchrony . Acorn production increased with the time since last fire, combined with additive or interactive effects of spring precipitation (+) or drought (–). Furthermore, multiple matrix regression models revealed that ramet pairs with shared fire history were more synchronous in seed production than ones that burned in different years. Long-term trends suggest that increasingly drier spring weather, in interaction with fire frequency, may drive a decline of seed production. Such declines could affect the community of acorn-reliant vertebrates in the Florida scrub, including endangered Florida scrub-jays ( Aphelocoma coerulescens ). These results illustrate that fire can function as a proximate driver of seed production in mast-seeding species, highlighting the increasingly recognized importance of interactions among reproductive strategies and disturbance regimes in structuring plant populations and communities. This article is part of the theme issue ‘The ecology and evolution of synchronized seed production in plants’.

Staging to join non‐kin groups in a classical cooperative breeder, the Florida scrub‐jay

“…Oak scrub is the jays' principal foraging habitat, and its annual acorn crop is a vigorously defended, essential resource for overwinter survival as jays depend on cached acorns for winter food (DeGange et al, 1989; Mumme et al, 2015; Woolfenden & Fitzpatrick, 1984). Fires are common in this landscape and affect acorn production and habitat structure associated with reproductive success: beginning 10 years post‐fire, population productivity starts to decline (Fitzpatrick & Bowman, 2016; Pesendorfer et al, 2021). At Archbold Biological Station, all wild birds are handled and banded under the US Geological Survey Bird Banding Lab permit (07732 for R.B.…”

“…Fires are common in this landscape and affect acorn production and habitat structure associated with reproductive success: beginning 10 years post-fire, population productivity starts to decline (Fitzpatrick & Bowman, 2016;Pesendorfer et al, 2021). At Archbold Biological Station, all wild birds are handled and banded under the US Geological Survey Bird Banding Lab permit (07732 for R.B.…”

Natural disturbances and masting: from mechanisms to fitness consequences

“…[62]). Even-aged populations that have regenerated together after a disturbance reach reproductive maturity at the same time, and are more likely to synchronize their reproduction in response to relevant environmental cues [63]. In Southeast Asia, even-aged bamboo forests (Melocanna baccifera) experience large-scale mortality after synchronized mass flowering and fruiting.…”

Tropical cyclone winds and precipitation stimulate cone production in the masting species longleaf pine (Pinus palustris)

“…Many plants exhibit a reproductive phenomenon known as mast seeding where seed production is highly variable in time and synchronous over large geographic areas (Janzen, 1971; Kelly, 1994; Koenig & Knops, 2005; Pesendorfer et al ., 2021). Several mechanisms have been proposed to explain the adaptive significance of masting, and the pattern has been linked to satiation of seed predators, increased wind pollination efficiency, and timing reproduction for favorable establishment conditions (Kelly, 1994; Pearse et al ., 2016).…”