DOI: 10.5061/dryad.s5pb0
title: Data from: Bolstered physical defences under nutrient-enriched conditions may facilitate a secondary foundational algal species in the South Pacific

description: 1. Humans have a long history of changing species’ ranges and habitat
 distributions, making studies of the ecological processes that may
 facilitate these changes of key importance, particularly in cases where a
 primary foundation species is replaced by another, less desirable species.
 2. We investigated the impact of nutrients and herbivory on Turbinaria
 ornata, a secondary foundational macroalga that depends on and likely
 competes with coral, the primary foundational community. T. ornata is also
 rapidly expanding in range and habitat across the South Pacific. We
 conducted: 1) a mesocosm experiment assessing relative nutrient
 limitation, 2) a field experiment comparing importance of nutrients (+/-)
 and herbivory (+/-) to biomass accumulation, and 3) an herbivory assay and
 toughness test comparing enriched and ambient thalli to assess changes to
 anti-herbivory defences. 3. We found no evidence of growth being nutrient
 limited in T. ornata; rather than stimulating growth, nutrient addition
 deterred herbivores. However, when physical toughness was removed,
 enriched algae were preferred, with consumption rates 25-fold those of
 unenriched algae. Additionally, enriched thalli were tougher than ambient
 thalli, suggesting physical defences were bolstered by nutrient
 enrichment. 4. Synthesis. We found a unique interaction where nutrients
 inhibit herbivory and facilitate Turbinaria ornata biomass accumulation.
 While concern is often placed on degradation of foundation species via
 anthropogenic change, instead here we show that anthropogenic change can
 facilitate secondary foundation species. This facilitation may allow a
 secondary foundation species to better compete with primary foundation
 species.
description: Turbinaria ornata all
 field and mesocosm experimentsThis data sheet is split
 into 6 different spread sheets. 1) "NvsP Gump" is for the
 nutrient enrichment mesocosm conducted in flow through tanks at the Gump
 Station. Ambient water was taken from Gump and treatment were fully
 crossed with +/- Nitrogen (Ntrt) and +/- Phosphorous (Ptrt) addition. The
 data includes intital and final heights (ht) and weights (wt), but the
 metric of interest in the paper was % Change in wt. Means and standard
 errors are calculated on the right for each treatment in this sheet. 2)
 "NvsP Sailing School" is set up the same as "NvsP
 Gump" except this experiment was conducted starting with ambient
 water from our second site, Sailing School. 3 and 4) "In situ
 Gump" and "In situ Sailing School" are data from field
 experiments at the two respective sites manipulating nutrient enrichments
 (+/- Nutrients or Ntrt) and access to herbivores (+/- Cage or Ctrt). Again
 %Change in Wt was the measure of interest and thalli that were completely
 lost (% Change Wt = 100%) were dropped from analysis because it cannot be
 distinguished whether these were lost by herbivory or implementation
 failure. 5) "Agar Test" contains initial and final areas for
 images of the three treatments--Ambient, Control, and +N
 (Osmocote/fertilizer enriched). "% Change in area" was
 calculated and used for analysis. Image areas were calculated in ImageJ
 software. 6) "Toughness Test"--Initial and final heights (ht)
 and weights (wt) were measured but "Toughness" was the metric of
 interested which was the weight required to penetrate the algal thallus by
 adding incremental amounts of sand to a field
 penetrometer.joe_all
 data.xlsx