DOI: 10.5061/dryad.pk0p2nh2c
title: Data from: Taxonomic, phylogenetic and functional <em>β</em>-diversity of stream algae is driven by the number of added nutrients and herbivory

description: A growing body of mostly observational research has examined how
 β-diversity and its turnover and nestedness components respond to
 environmental gradients across taxonomic, phylogenetic, and functional
 dimensions. To our knowledge, this is the first manipulative investigation
 to assess how two major environmental influences—nutrient enrichment and
 herbivory—control β-diversity and its components across dimensions in
 phototrophs. We used algal data from field and lab experiments,
 manipulating herbivory and/or the number of added nutrients (NAN), which
 ranged from zero to three (N, P, and Fe) or four (N, P, Fe, and Mn). We
 compared control/nutrient treatment vs. control communities and non-grazed
 vs. grazed communities in terms of taxonomic, phylogenetic, and functional
 diversity. Taxonomic and phylogenetic β-diversity (βSor) was partitioned
 into turnover (βSim) and nestedness (βNes) components. We proposed a novel
 partitioning approach for functional β-diversity, outperforming the
 conventional approach, which calculates βSor, βSim, and βNes. Instead, we
 used Bray-Curtis distances derived from the number of taxa within
 morpho-functional groups and calculated overall functional β-diversity
 (βBC) and its balance (βBal) and gradient (βGra) components. We developed
 three hypotheses predicting that i) βNes and βGra would rise at higher NAN
 because of increased taxonomic richness, and phylogenetic and functional
 diversity (hypothesis 1); ii) grazing would either reduce (hypothesis 2a)
 or elevate βNes and βGra (hypothesis 2b) depending on the balance between
 extinction of grazer-sensitive taxa vs. establishment of grazer-resistant
 taxa; and iii) the relative importance of βNes and βGra would depend on
 NAN and dimension. Our results supported hypotheses 1, 2b, and 3. Across
 dimensions, enrichment with multiple nutrients elevated biodiversity, the
 nestedness and gradient components of β-diversity, and often, the overall
 β-diversity. Herbivory contributed to this increase by promoting
 grazer-resistant but competitively inferior taxa. Thus, streams with
 higher levels of both micro- and macronutrients and unimpacted herbivorous
 fauna may represent biodiversity hotspots and targets for conservation.
 The relative importance of βNes and βGra increased with NAN, and at the
 functional dimension, βGra was the dominant component. Therefore, shorter
 environmental gradients may promote turnover, while longer gradients,
 colonization/extinction, the latter becoming particularly prominent at the
 functional dimension.
description: # Data from: Taxonomic, phylogenetic and functional *β*-diversity of
 stream algae is driven by the number of added nutrients and herbivory
 Dataset DOI: [10.5061/dryad.pk0p2nh2c](10.5061/dryad.pk0p2nh2c) ##
 Description of the data and file structure **The Llano dataset.** We
 obtained data from a previously conducted field experiment with algae in
 the Llano River, TX. The number of added nutrients, ranging from zero
 (control) to four (treatment), was manipulated by adding agar only or agar
 enriched with N, P, Fe, Mn, or all their combinations to clay dishes.
 Malathion was added to half of the dishes for herbivory suppression.
 Control and each nutrient treatment had three replicates per Malathion
 treatment (16 nutrient combinations x 3 replicates x 2 Malathion
 treatments = 96 dishes). The dishes were deployed in the river, and after
 42 days, algae were scraped from the flat surface of the dishes. Algae
 were identified and measured for a biovolume
 estimate. The_Llano_dataset.csv contains sample ID, treatment, replicate,
 number of added nutrients, and taxonomic, morphological, and functional
 information for the identified taxa. Taxa with only genus identifications
 have n/a in the columns for species and variety name. **Variables in
 The_Llano_dataset.csv with descriptions.** | Column name | Description | |
 :-------------------------------- |
 :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Sample ID | Unique sample identifier | | Nutrient treatment | Control samples (no nutrients added) or samples with added nitrogen (N), phosphorus (P), iron (Fe), manganese (Mn), or their combinations | | Malathion treatment | Samples with or without added Malathion | | Replicate | One of three replicates per nutrient treatment | | Number of added nutrients | Varies from 0 to 4 added nutrients | | Taxon | Scientific name | | Ecological guild | Low-profile (LP), high-profile (HP), motile (M), or nitrogen fixer (NF) | | Growth habit | Unicellular, colonial, or filamentous | | Biovolume (um\^3) | Biovolume (μm^3^) per unit, which is represented by a single cell for unicellular soft algae and all diatoms, a single coenobium, a square measuring 25 µm x 25 µm for colonies of soft algae, or a 25 µm length of a filament | | Biovolume class | Biovolume units were classified into five classes, 1 to 5, corresponding to exponents of 10 (10^1^ to 10^5^) | | Morpho-functional group | A combination of ecological guild x biovolume class | | Algal group | Common name | | Taxonomic level of identification | Genus, species, or variety | | Kingdom | Taxonomic category | | Phylum | Taxonomic category | | Class | Taxonomic category | | Order | Taxonomic category | | Family | Taxonomic category | | Genus | Taxonomic category | | Species | Taxonomic category | | Variety | Taxonomic category | **Lab experiments dataset.** We obtained data from two experimental runs in recirculating laboratory streams (4.5 L glass dishes), previously performed at the University of Texas at Arlington. The number of added nutrients, ranging from zero (control) to three (treatment), was manipulated by adding COMBO medium with no nutrients or COMBO medium enriched with N, P, Fe, or all their combinations to the glass dishes. The dishes were lined with natural stone tiles and inoculated with algae from local streams at the beginning of each experimental run. Control and each nutrient treatment had three replicates (8 nutrient combinations x 3 replicates = 24 dishes). Algae were collected by scraping three random tiles from each dish at day 40 and day 60 in the first and second runs, respectively. The material from the three tiles was composited. Algae were identified and measured for a biovolume estimate. Lab_dataset.csv contains sample ID, treatment, replicate, run, number of added nutrients, and taxonomic, morphological, and functional information for the identified taxa. Taxa with only genus identifications have n/a in the columns for species and variety name. **Variables in Lab_dataset.csv with descriptions.** | Column name | Description | | :-------------------------------- | :----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | Sample ID | Unique sample identifier | | Nutrient treatment | Control samples (no nutrients added) or samples with added nitrogen (N), phosphorus (P), iron (Fe), or their combinations | | Replicate | One of three replicates per nutrient treatment | | Experimental run | One of two experimental runs | | Number of added nutrients | Varies from 0 to 3 added nutrients | | Taxon | Scientific name | | Ecological guild | Low-profile (LP), high-profile (HP), motile (M), or nitrogen fixer (NF) | | Growth habit | Unicellular, colonial, or filamentous | | Biovolume (um\^3) | Biovolume (μm^3^) per unit, which is represented by a single cell for unicellular soft algae and all diatoms, a single coenobium, a square measuring 25 µm x 25 µm for colonies of soft algae, or a 25 µm length of a filament | | Biovolume class | Biovolume units were classified into five classes, 1 to 5, corresponding to exponents of 10 (10^1^ to 10^5^) | | Morpho-functional group | A combination of ecological guild x biovolume class | | Algal group | Common name | | Taxonomic level of identification | Genus, species, or variety | | Kingdom | Taxonomic category | | Phylum | Taxonomic category | | Class | Taxonomic category | | Order | Taxonomic category | | Family | Taxonomic category | | Genus | Taxonomic category | | Species | Taxonomic category | | Variety | Taxonomic category |