Effects of hydrology on the growth and physiology of an invasive exotic, Lygodium microphyllum (Old World climbing fern)

Abstract

Summary We conducted a glasshouse study to examine effects of hydrology on the growth and physiology of Lygodium microphyllum (Old World climbing fern), an invasive exotic that is rapidly colonising forested wetlands in Florida, USA. We assessed the fern’s growth and physiological responses to three hydrological treatments – flood, drought and field capacity. To further explore the physiology of the treatment responses of L. microphyllum, we also sprayed each plant with gibberellic acid, paclobutrazol (gibberellin inhibitor) or a water control solution (at a rate of 5 mL three times per week) using a 3 × 3 factorial design. Flooding reduced relative growth rate by 55%, whereas periodic exposure of ferns to a soil water potential of −1 MPa did not affect growth or physiology. Flooding led to substantial decreases in specific leaf area and area‐based rates of pinna photosynthesis, resulting in a 64% lower rate of photosynthesis per unit pinna mass. Application of growth regulators had no effect on fern growth, morphology or physiology. Even though flooding substantially reduced growth, L. microphyllum still showed a positive relative growth rate after >2 months of inundated soils. This apparent hydrological plasticity is likely a contributing factor to the introduced fern’s widespread establishment across a range of plant communities within the Florida Everglades ecosystem. Short‐term manipulation of site hydrology does not appear to be an effective management option. Consequently, this has considerable implications for the Everglades, which is undergoing a 30‐year system‐wide hydrological restoration.

Effect of soil pH on growth, nutrient uptake, and mycorrhizal colonization in exotic invasive Lygodium microphyllum

“…The allometric relationship between stem length and total mass (R 2 = 0.92) from the initial harvest was developed to estimate the initial plant mass of the experimental plants and to calculate the relative growth rate (RGR) (Gandiaga et al 2009). The RGR (mg g -1 day -1 ) was calculated for each individual plant used for the experiment following the method by Evans (1972):…”

“…It has the ability to grow in varying hydrological (Gandiaga et al 2009), nutrient (Volin et al 2010), and light conditions (Volin et al 2004). Analysis of soil samples from both its native range and invaded region has shown that although L. microphyllum grows in highly acidic soils in its native range in Australia, it is thriving in close-to-neutral soils in Florida (Soti et al 2014).…”

Effect of exotic invasive old world climbing fern (lygodium microphyllum) on soil properties

“…Managing L. microphyllum has been a significant challenge for land resource managers and researchers due to its extensive rapid invasion in natural areas of south Florida. Once established, L. microphyllum dominates both understory and overstory native wetland habitats, and has the ability to grow in varying hydrological (Gandiaga et al 2009), nutrient (Volin et al 2010), soil pH (Soti et al 2014, and light gradients (Volin et al 2004). Soti et al (2014) have shown that L. microphyllum is highly dependent on mycorrhizal fungi for growth and phosphorus uptake which could highly enhance its invasiveness.…”

The Effects of Fire on Spore Viability of Lygodium microphyllum (Old World Climbing Fern)

“…The rhizome grows at, or just below, the soil surface and, once established, can withstand temporary inundation and variable water levels (Gandiaga et al 2009, Mueller 1982a, Volin et al 2004. Leaves form dorsally on the rhizome, follow a single rank, and develop from a single cell produced by the apical meristem (Mueller 1982a).…”