Presentation Title

Plasticity in a Tropical Tree: Functional Trait Variation Across a Light Gradient and Three Substrate Types in Pentaclethra macroloba

Start Date

November 2016

End Date

November 2016

Location

HUB 302-168

Type of Presentation

Poster

Abstract

The La Selva biological station is a 1600 ha reserve of tropical rainforest in the Caribbean lowlands of Costa Rica. Three broad soil types comprise La Selva: alluvial, which is comprised of periodic sediment deposits from river flooding, volcanic, which consists of eroded lava flows, and swamps, which are characterized by either seasonal or permanent inundation. Alluvial, swamp, and volcanic soil types also range from high, to intermediate, to low fertility respectively. In previous studies, the distribution of at least 30% of tree species observed have shown significant soil type preference. Pentaclethra macroloba is the most common species of tree at La Selva, accounting for 40% of all larger diameter trees. P. macroloba has also been observed to occur in high abundance throughout all soil types and locations ranging from high light to full shade. Because it has the ability to thrive in a wide variety of environments, I investigated whether P. macroloba alters its phenotype to adapt to its specific light and soil conditions or if it possesses one all encompassing, high fitness phenotype. In 15 separate 25x25m plots spread throughout the three soil types, I measured various functional traits of individual P. macroloba saplings and characterized the light level for each sapling using a hemispherical fisheye photo. My results show that saplings in swampy soil are significantly larger than those in either volcanic or alluvial soil (P < 0.001), yet also experience significantly more light (P < 0.001). However, when examining saplings of similar height (60-70 cm), there are no significant differences between any functional traits throughout soil types (P > 0.06) despite significantly different light environments (P = 0.003). As such, when controlling for sapling size, P. macroloba appears to maintain a consistent phenotype across various soil types and light conditions.

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Nov 12th, 1:00 PM Nov 12th, 2:00 PM

Plasticity in a Tropical Tree: Functional Trait Variation Across a Light Gradient and Three Substrate Types in Pentaclethra macroloba

HUB 302-168

The La Selva biological station is a 1600 ha reserve of tropical rainforest in the Caribbean lowlands of Costa Rica. Three broad soil types comprise La Selva: alluvial, which is comprised of periodic sediment deposits from river flooding, volcanic, which consists of eroded lava flows, and swamps, which are characterized by either seasonal or permanent inundation. Alluvial, swamp, and volcanic soil types also range from high, to intermediate, to low fertility respectively. In previous studies, the distribution of at least 30% of tree species observed have shown significant soil type preference. Pentaclethra macroloba is the most common species of tree at La Selva, accounting for 40% of all larger diameter trees. P. macroloba has also been observed to occur in high abundance throughout all soil types and locations ranging from high light to full shade. Because it has the ability to thrive in a wide variety of environments, I investigated whether P. macroloba alters its phenotype to adapt to its specific light and soil conditions or if it possesses one all encompassing, high fitness phenotype. In 15 separate 25x25m plots spread throughout the three soil types, I measured various functional traits of individual P. macroloba saplings and characterized the light level for each sapling using a hemispherical fisheye photo. My results show that saplings in swampy soil are significantly larger than those in either volcanic or alluvial soil (P < 0.001), yet also experience significantly more light (P < 0.001). However, when examining saplings of similar height (60-70 cm), there are no significant differences between any functional traits throughout soil types (P > 0.06) despite significantly different light environments (P = 0.003). As such, when controlling for sapling size, P. macroloba appears to maintain a consistent phenotype across various soil types and light conditions.