DOI: 10.5061/dryad.76hdr7sw1
title: Ontogenetic diversity buffers communities against consequences of species loss

description: Biodiversity can be measured at multiple organizational scales. While
 traditional studies have focused at taxonomic diversity, recent studies
 have emphasized the ecological importance of diversity within populations.
 However, it is unclear how these different scales of diversity interact to
 determine the consequence of species loss. Here we asked how predator
 diversity and presence of ontogenetic diversity within predator
 populations influences community structure. Ontogenetic diversity arises
 from shifts in the traits and ecology of individuals during ontogeny and
 it is one of the biggest sources of intraspecific diversity. However,
 whether it dampens or strengthens the negative consequences of with
 species loss is poorly understood. To study this interaction of species
 diversity and ontogenetic diversity, we experimentally manipulated
 predator species diversity and diversity of developmental stages within
 focal predator species and analyzed their joint effect on predator and
 prey survival, biomass, and prey community structure in experimental pond
 systems. While individual effects of ontogenetic diversity were often
 species-specific, losing predator species from the community often had a
 much smaller or no effect on prey survival, biomass, or community
 structure when all predator populations had high ontogenetic diversity.
 Thus, ontogenetic diversity within populations buffered against some of
 the consequences of biodiversity loss at higher organizational levels.
 Because the experiment controlled mean per capita size and biomass across
 structured vs. unstructured populations, this pattern was not driven by
 differences in biomass of predators. Instead, results suggest that effects
 were driven by changes in the functional roles and indirect interactions
 across and within species. This indicates that even if all environmental
 conditions are similar, differences in the intrinsic structure of
 populations can modify the consequences of biodiversity loss. Together,
 these results revealed the importance of ontogenetic diversity within
 species for strengthening the resilience of natural communities to
 consequences of biodiversity loss and emphasize the need to integrate
 biodiversity patterns across organizational scales. 
description: Goals: The main goal of this study is to
 examine how ontogenetic  diversity within species  interacts with species
 diversity and whether diversity within species can buffer against loss of
 species diversity. The experiment has 9 treatments manipulating size
 diversity (M = medium stage vs SML = very wide stage range) of 3 focal
 predator species. Species are either alone (single species)(A,B,C) or all
 three combined (ABC) in an additive design. The density of each focal
 predator is constant acrosss species, size &  diversity treatment.
 Biomass is similar across size treatments, and comparable across species
 (within natural limits of their morphology). General
 setup and data: The data are from a mesocosm experiment
 that was carried in from July 12th to August 11th 2016, at the South
 Campus Research Facility of Rice University, Houston, TX. 
 A complete description of the methods are given in the
 corresonding manuscript. Briefly, experiments were carried out in 300L PVC
 cylindrical mesocosm with 60% shade cloth filled with declorinated water.
 We set up 60 mesocosm in an open field outdors in complete randomized
 block design. We then added several tadpole species, and concentrated
 zooplankton from local ponds. Finally, we factorially manipulated the size
 structure and presence absence of three focal invertebrate predators to
 examine effects on tadpole, invertebrate, and zooplankton
 community.    Data includes:
 Experimental design Final focal predator
 abundance and mass following final take down. Final
 Invertebrate dry mass and species counts following final take
 down. Metamorph mass & emergence date collected
 daily Final total tadpole dry mass for two amphibian
 species at final take down. Zooplankton abundance by
 species based on subsamples obtained with depth integrated tube
 samplers.   Periphyton density based on Chlorophyll a
 concentration extracted from glass slides Phytoplankton
 density based on InVivo measurements.  Dissolve oxygem
 concentration and mg/L sampled three times consecutely at sunrise
 7:10-8:30am (s1), sunset 7:40-8:20pm (s2) and sunrise , 7:10-7:40am (s3)
 on August 8-August 9th.   
description: The data set includes an addotated RMarkdown file
 (FinalAnalysisSizevsSpecies.Rmd)  that documents all parts of the analysis
 and figures that were used in the main manusript, and corresponding data
 files.  Data set Tadsize, Metao are individual based
 and thus have multiple values per replicates. Data set Zoops, InvDryMass,
 TadsDryMass have one value per replicate.  Each data
 file X has corresponding readme_X file describing all data
 labels.