Plains and wood bison fecal samples, diet content, and diet quality
Data files
Mar 10, 2025 version files 1.35 MB
-
EIPN_BisonScatDataCollection.csv
14.77 KB
-
JV_DietContent_EINP.csv
1.30 MB
-
NIRS_EINP.csv
12.65 KB
-
README.md
26.05 KB
Abstract
Understanding ecological niche is critical to the management and conservation of any species or population. For herbivores, dietary niche is critical for understanding habitat suitability, carrying capacity, and population and community viability. In closely related species with similar morphologies, dietary niches can diverge depending on environmental and seasonal factors. Elk Island National Park in Alberta, Canada, contains populations of both American bison (Bison bison) subspecies—plains bison (B. b. bison) and wood bison (B. b. athabascae)—in similar but separate habitats located at the historical confluence of the subspecies’ distributions. Using generalized additive models and nutritional geometry, we compared the subspecies’ dietary niches in terms of content and quality continuously for one year (Dec 2020 – Nov 2021). Both subspecies consumed primarily graminoids during winter, spring, and fall and incorporated a variety of forbs and woody plants during summer. Plains bison diets contained more upland grasses and digestible organic matter in their diet and less wetland graminoids (e.g., sedges) throughout the year. We also found differing dietary niches between the subspecies during the spring and summer months. Our unique, continuous analysis of annual diet content and quality can deliver insight into the similarities and differences between subspecies’ dietary niches that should help improve management decisions, such as better matching between source populations and release areas for future translocations.
https://doi.org/10.5061/dryad.866t1g21r
Description of the data and file structure
Files and variables
File: NIRS_EINP.csv
Description: Near-infrared spectroscopy (NIRS) data to determine diet quality metrics from composite, bison fecal samples collected in Elk Island National Park, Alberta, Canada.
Variables
- FecalID: Unique identification for each composite fecal sample.
- Subspecies: Bison subspecies, either Plains or Wood
- Season: Season classification either (winter = December - February, spring = March - May, Summer = June - August, or Fall = September - November)
- Month: Month of year
- Mon_num: Number corresponding to month (e.g., January = 1, February = 2, etc.)
- Week: Week within month of fecal sample collection, either 1, 2, 3 or 4
- Date: Calendar date (m/d/yyyy)
- Northing: UTM zone 12 northing
- Easting: UTM zone 12 easting
- CP: crude protein percentage
- H: H statistics indicate whether a sample is similar to the database used to create the calibration.
- DOM: Digestible organic matter percentage
- DOM_CP: ratio of digestible organic matter percentage to crude protein percentage
- FN: fecal nitrogen
- FP: fecal phosphorus
File: EIPN_BisonScatDataCollection.csv
Description: Data related to collection of fecal samples in the field.
Variables
- JoVe #: Identification number for fecal samples to be sent to Jonah Ventures for DNA metabarcoding analysis of content.
- Composite ID: Unique identifier assigned to composite sample
- Vial Filled?: Yes or No, was the vial filled
- Season: Season classification either (winter = December - February, spring = March - May, Summer = June - August, or Fall = September - November)
- Month: calendar month
- Week: Week within month of fecal sample collection, either 1, 2, 3 or 4
- Date Collected: Day within month of fecal sample collection
- Ordinal Day: Ordinal or Julian day of collection
- Days Old: Age of fecal sample estimated based on visual inspection in field by park biologists and last known date of bison presence
- Collected By: First name of park employee collection sample
- Subspecies: Either Plains or Wood
- Location: Field description of location
- Northing: UTM zone 12 northing
- Easting: UTM zone 12 easting
- Comments: Notes from park biologist
- Sent: protein: unused column
- Sent: diet: unused column
File: JV_DietContent_EINP.csv
Description: DNA metabarcoding analysis results as conducted by Jonah Ventures
Variables
- TestId: All tests were conducted on "trnl" sequences
- ESVId: Exact sequence variants (ESV) identification for each unique trnl sequence
- sequence: trnl sequence
- Kingdom: Identified plant Kingdom
- Phylum: Identified plant Phylum
- Class: Identified plant Class
- Order: Identified plant Order
- Family: Identified plant Family
- Genus: Identified plant Genus
- Species: Identified plant Species
- FG1: Assigned forage group grass, sedge, forb, or browse
- FG2: Assigned forage group graminoid, forb, or browse
- % match: Percentage of match to identified plant taxa
- ** **# species: number of species with the identified percentage match
- Wood.F.Nov4: Read count (number of times this ESVID was counted in this sample) for the November, week 4 wood bison composite sample
- Wood.F.Nov3: Read count (number of times this ESVID was counted in this sample) for the November, week 3 wood bison composite sample
- Wood.F.Nov2: Read count (number of times this ESVID was counted in this sample) for the November, week 2 wood bison composite sample
- Wood.F.Nov1: Read count (number of times this ESVID was counted in this sample) for the November, week 1 wood bison composite sample
- Wood.F.Oct4: Read count (number of times this ESVID was counted in this sample) for the October, week 4 wood bison composite sample
- Wood.F.Oct3: Read count (number of times this ESVID was counted in this sample) for the October, week 3 wood bison composite sample
- Wood.F.Oct2: Read count (number of times this ESVID was counted in this sample) for the October, week 2 wood bison composite sample
- Wood.F.Oct1: Read count (number of times this ESVID was counted in this sample) for the October, week 1 wood bison composite sample
- Wood.F.Sep4: Read count (number of times this ESVID was counted in this sample) for the September, week 4 wood bison composite sample
- Wood.F.Sep3: Read count (number of times this ESVID was counted in this sample) for the September, week 3 wood bison composite sample
- Wood.F.Sep2: Read count (number of times this ESVID was counted in this sample) for the September, week 2 wood bison composite sample
- Wood.F.Sep1: Read count (number of times this ESVID was counted in this sample) for the September, week 1 wood bison composite sample
- Wood.Su.Aug4: Read count (number of times this ESVID was counted in this sample) for the August, week 4 wood bison composite sample
- Wood.Su.Aug3: Read count (number of times this ESVID was counted in this sample) for the August, week 3 wood bison composite sample
- Wood.Su.Aug2: Read count (number of times this ESVID was counted in this sample) for the August, week 2 wood bison composite sample
- Wood.Su.Aug1: Read count (number of times this ESVID was counted in this sample) for the August, week 1 wood bison composite sample
- Wood.Su.Jul4: Read count (number of times this ESVID was counted in this sample) for the July, week 4 wood bison composite sample
- Wood.Su.Jul3: Read count (number of times this ESVID was counted in this sample) for the July, week 3 wood bison composite sample
- Wood.Su.Jul2: Read count (number of times this ESVID was counted in this sample) for the July, week 2 wood bison composite sample
- Wood.Su.Jul1: Read count (number of times this ESVID was counted in this sample) for the July, week 1 wood bison composite sample
- Wood.Su.Jun4: Read count (number of times this ESVID was counted in this sample) for the June, week 4 wood bison composite sample
- Wood.Su.Jun3: Read count (number of times this ESVID was counted in this sample) for the June, week 3 wood bison composite sample
- Wood.Su.Jun2: Read count (number of times this ESVID was counted in this sample) for the June, week 2 wood bison composite sample
- Wood.Su.Jun1: Read count (number of times this ESVID was counted in this sample) for the June, week 1 wood bison composite sample
- Wood.Sp.May4: Read count (number of times this ESVID was counted in this sample) for the May, week 4 wood bison composite sample
- Wood.Sp.May3: Read count (number of times this ESVID was counted in this sample) for the May, week 3 wood bison composite sample
- Wood.Sp.May2: Read count (number of times this ESVID was counted in this sample) for the May, week 2 wood bison composite sample
- Wood.Sp.May1: Read count (number of times this ESVID was counted in this sample) for the May, week 1 wood bison composite sample
- Wood.Sp.Apr4: Read count (number of times this ESVID was counted in this sample) for the April, week 4 wood bison composite sample
- Wood.Sp.Apr3: Read count (number of times this ESVID was counted in this sample) for the April, week 3 wood bison composite sample
- Wood.Sp.Apr2: Read count (number of times this ESVID was counted in this sample) for the April, week 2 wood bison composite sample
- Wood.Sp.Apr1: Read count (number of times this ESVID was counted in this sample) for the April, week 1 wood bison composite sample
- Wood.Sp.Mar4: Read count (number of times this ESVID was counted in this sample) for the March, week 4 wood bison composite sample
- Wood.Sp.Mar3: Read count (number of times this ESVID was counted in this sample) for the March, week 3 wood bison composite sample
- Wood.Sp.Mar2: Read count (number of times this ESVID was counted in this sample) for the March, week 2 wood bison composite sample
- Wood.Sp.Mar1: Read count (number of times this ESVID was counted in this sample) for the March, week 1 wood bison composite sample
- Wood.W.Feb4: Read count (number of times this ESVID was counted in this sample) for the February, week 4 wood bison composite sample
- Wood.W.Feb3: Read count (number of times this ESVID was counted in this sample) for the February, week 3 wood bison composite sample
- Wood.W.Feb2: Read count (number of times this ESVID was counted in this sample) for the February, week 2 wood bison composite sample
- Wood.W.Feb1: Read count (number of times this ESVID was counted in this sample) for the February, week 1 wood bison composite sample
- Wood.W.Jan4: Read count (number of times this ESVID was counted in this sample) for the January, week 4 wood bison composite sample
- Wood.W.Jan3: Read count (number of times this ESVID was counted in this sample) for the January, week 3 wood bison composite sample
- Wood.W.Jan2: Read count (number of times this ESVID was counted in this sample) for the January, week 2 wood bison composite sample
- Wood.W.Jan1: Read count (number of times this ESVID was counted in this sample) for the January, week 1 wood bison composite sample
- Wood.W.Dec4: Read count (number of times this ESVID was counted in this sample) for the December, week 4 wood bison composite sample
- Wood.W.Dec3: Read count (number of times this ESVID was counted in this sample) for the December, week 3 wood bison composite sample
- Wood.W.Dec2: Read count (number of times this ESVID was counted in this sample) for the December, week 2 wood bison composite sample
- Wood.W.Dec1: Read count (number of times this ESVID was counted in this sample) for the December, week 1 wood bison composite sample
- Wood.Ann.ReadSum: Read sum (sum of number of times this ESVID was counted in this sample) for annual wood bison composite samples
- Wood.Ann.ReadSum.mu: Mean of read count (number of times this ESVID was counted in this sample) for the December, week 4 wood bison composite sample
- Wood.F.RS: Read sum (sum of number of times this ESVID was counted in this sample) for fall (September, October, November) wood bison composite samples
- Wood.F.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for fall (September, October, November) wood bison composite sample
- Wood.Su.RS: Read sum (sum of number of times this ESVID was counted in this sample) for summer (June, July, August) wood bison composite samples
- Wood.Su.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for summer (June, July, August) wood bison composite sample
- Wood.Sp.RS: Read sum (sum of number of times this ESVID was counted in this sample) for spring (March, April, May) wood bison composite samples
- Wood.Sp.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for spring (March, April, May) wood bison composite sample
- Wood.W.RS: Read sum (sum of number of times this ESVID was counted in this sample) for winter (December, January, February) wood bison composite samples
- Wood.W.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter (December, January, February) wood bison composite sample
- Wood.Nov.RS: Read sum (sum of number of times this ESVID was counted in this sample) for November wood bison composite samples
- Wood.Nov.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for November wood bison composite sample
- Wood.Oct.RS: Read sum (sum of number of times this ESVID was counted in this sample) for October wood bison composite samples
- Wood.Oct.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for October wood bison composite sample
- Wood.Sept.RS: Read sum (sum of number of times this ESVID was counted in this sample) for September wood bison composite samples
- Wood.Sept.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for September wood bison composite sample
- Wood.Aug.RS: Read sum (sum of number of times this ESVID was counted in this sample) for August wood bison composite samples
- Wood.Aug.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for August wood bison composite sample
- Wood.Jul.RS: Read sum (sum of number of times this ESVID was counted in this sample) for July wood bison composite samples
- Wood.Jul.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for July wood bison composite sample
- Wood.Jun.RS: Read sum (sum of number of times this ESVID was counted in this sample) for June wood bison composite samples
- Wood.Jun.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for June wood bison composite sample
- Wood.May.RS: Read sum (sum of number of times this ESVID was counted in this sample) for May wood bison composite samples
- Wood.May.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter May wood bison composite sample
- Wood.Apr.RS: Read sum (sum of number of times this ESVID was counted in this sample) for April wood bison composite samples
- Wood.Apr.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for April wood bison composite sample
- Wood.Mar.RS: Read sum (sum of number of times this ESVID was counted in this sample) for March wood bison composite samples
- Wood.Mar.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter March wood bison composite sample
- Wood.Feb.RS: Read sum (sum of number of times this ESVID was counted in this sample) for February wood bison composite samples
- Wood.Feb.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter February wood bison composite sample
- Wood.Jan.RS: Read sum (sum of number of times this ESVID was counted in this sample) for January wood bison composite samples
- Wood.Jan.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for January, wood bison composite sample
- Wood.Dec.RS: Read sum (sum of number of times this ESVID was counted in this sample) for December wood bison composite samples
- Wood.Dec.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for December wood bison composite sample
- Plains.F.Nov4: Read count (number of times this ESVID was counted in this sample) for the November, week 4 plains bison composite sample
- Plains.F.Nov3: Read count (number of times this ESVID was counted in this sample) for the November, week 3 plains bison composite sample
- Plains.F.Nov2: Read count (number of times this ESVID was counted in this sample) for the November, week 2 plains bison composite sample
- Plains.F.Nov1: Read count (number of times this ESVID was counted in this sample) for the November, week 1 plains bison composite sample
- Plains.F.Oct4: Read count (number of times this ESVID was counted in this sample) for the October, week 4 plains bison composite sample
- Plains.F.Oct3: Read count (number of times this ESVID was counted in this sample) for the October, week 3 plains bison composite sample
- Plains.F.Oct2: Read count (number of times this ESVID was counted in this sample) for the October, week 2 plains bison composite sample
- Plains.F.Oct1: Read count (number of times this ESVID was counted in this sample) for the October, week 1 plains bison composite sample
- Plains.F.Sep4: Read count (number of times this ESVID was counted in this sample) for the September, week 4 plains bison composite sample
- Plains.F.Sep3: Read count (number of times this ESVID was counted in this sample) for the September, week 3 plains bison composite sample
- Plains.F.Sep2: Read count (number of times this ESVID was counted in this sample) for the September, week 2 plains bison composite sample
- Plains.F.Sep1: Read count (number of times this ESVID was counted in this sample) for the September, week 1 plains bison composite sample
- Plains.Su.Aug4: Read count (number of times this ESVID was counted in this sample) for the August, week 4 plains bison composite sample
- Plains.Su.Aug3: Read count (number of times this ESVID was counted in this sample) for the August, week 3 plains bison composite sample
- Plains.Su.Aug2: Read count (number of times this ESVID was counted in this sample) for the August, week 2 plains bison composite sample
- Plains.Su.Aug1: Read count (number of times this ESVID was counted in this sample) for the August, week 1 plains bison composite sample
- Plains.Su.Jul4: Read count (number of times this ESVID was counted in this sample) for the July, week 4 plains bison composite sample
- Plains.Su.Jul3: Read count (number of times this ESVID was counted in this sample) for the July, week 3 plains bison composite sample
- Plains.Su.Jul2: Read count (number of times this ESVID was counted in this sample) for the July, week 2 plains bison composite sample
- Plains.Su.Jul1: Read count (number of times this ESVID was counted in this sample) for the July, week 1 plains bison composite sample
- Plains.Su.Jun4: Read count (number of times this ESVID was counted in this sample) for the June, week 4 plains bison composite sample
- Plains.Su.Jun3: Read count (number of times this ESVID was counted in this sample) for the June, week 3 plains bison composite sample
- Plains.Su.Jun2: Read count (number of times this ESVID was counted in this sample) for the June, week 2 plains bison composite sample
- Plains.Su.Jun1: Read count (number of times this ESVID was counted in this sample) for the June, week 1 plains bison composite sample
- Plains.Sp.May4: Read count (number of times this ESVID was counted in this sample) for the May, week 4 plains bison composite sample
- Plains.Sp.May3: Read count (number of times this ESVID was counted in this sample) for the May, week 3 plains bison composite sample
- Plains.Sp.May2: Read count (number of times this ESVID was counted in this sample) for the May, week 2 plains bison composite sample
- Plains.Sp.May1: Read count (number of times this ESVID was counted in this sample) for the May, week 1 plains bison composite sample
- Plains.Sp.Apr4: Read count (number of times this ESVID was counted in this sample) for the April, week 4 plains bison composite sample
- Plains.Sp.Apr3: Read count (number of times this ESVID was counted in this sample) for the April, week 3 plains bison composite sample
- Plains.Sp.Apr2: Read count (number of times this ESVID was counted in this sample) for the April, week 2 plains bison composite sample
- Plains.Sp.Apr1: Read count (number of times this ESVID was counted in this sample) for the April, week 1 plains bison composite sample
- Plains.Sp.Mar4: Read count (number of times this ESVID was counted in this sample) for the March, week 4 plains bison composite sample
- Plains.Sp.Mar3: Read count (number of times this ESVID was counted in this sample) for the March, week 3 plains bison composite sample
- Plains.Sp.Mar2: Read count (number of times this ESVID was counted in this sample) for the March, week 2 plains bison composite sample
- Plains.Sp.Mar1: Read count (number of times this ESVID was counted in this sample) for the March, week 1 plains bison composite sample
- Plains.W.Feb4: Read count (number of times this ESVID was counted in this sample) for the February, week 4 plains bison composite sample
- Plains.W.Feb3: Read count (number of times this ESVID was counted in this sample) for the February, week 3 plains bison composite sample
- Plains.W.Feb2: Read count (number of times this ESVID was counted in this sample) for the February, week 2 plains bison composite sample
- Plains.W.Feb1: Read count (number of times this ESVID was counted in this sample) for the February, week 1 plains bison composite sample
- Plains.W.Jan4: Read count (number of times this ESVID was counted in this sample) for the January, week 4 plains bison composite sample
- Plains.W.Jan3: Read count (number of times this ESVID was counted in this sample) for the January, week 3 plains bison composite sample
- Plains.W.Jan2: Read count (number of times this ESVID was counted in this sample) for the January, week 2 plains bison composite sample
- Plains.W.Jan1: Read count (number of times this ESVID was counted in this sample) for the January, week 1 plains bison composite sample
- Plains.W.Dec4: Read count (number of times this ESVID was counted in this sample) for the December, week 4 plains bison composite sample
- Plains.W.Dec3: Read count (number of times this ESVID was counted in this sample) for the December, week 3 plains bison composite sample
- Plains.W.Dec2: Read count (number of times this ESVID was counted in this sample) for the December, week 2 plains bison composite sample
- Plains.W.Dec1: Read count (number of times this ESVID was counted in this sample) for the December, week 1 plains bison composite sample
- Plains.Ann.ReadSum: Read sum (sum of number of times this ESVID was counted in this sample) for annual plains bison composite samples
- Plains.Ann.ReadSum.mu: Mean of read count (number of times this ESVID was counted in this sample) for the December, week 4 plains bison composite sample
- Plains.F.RS: Read sum (sum of number of times this ESVID was counted in this sample) for fall (September, October, November) plains bison composite samples
- Plains.F.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for fall (September, October, November) plains bison composite sample
- Plains.Su.RS: Read sum (sum of number of times this ESVID was counted in this sample) for summer (June, July, August) plains bison composite samples
- Plains.Su.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for summer (June, July, August) plains bison composite sample
- Plains.Sp.RS: Read sum (sum of number of times this ESVID was counted in this sample) for spring (March, April, May) plains bison composite samples
- Plains.Sp.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for spring (March, April, May) plains bison composite sample
- Plains.W.RS: Read sum (sum of number of times this ESVID was counted in this sample) for winter (December, January, February) plains bison composite samples
- Plains.W.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter (December, January, February) plains bison composite sample
- Plains.Nov.RS: Read sum (sum of number of times this ESVID was counted in this sample) for November plains bison composite samples
- Plains.Nov.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for November plains bison composite sample
- Plains.Oct.RS: Read sum (sum of number of times this ESVID was counted in this sample) for October plains bison composite samples
- Plains.Oct.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for October plains bison composite sample
- Plains.Sept.RS: Read sum (sum of number of times this ESVID was counted in this sample) for September plains bison composite samples
- Plains.Sept.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for September plains bison composite sample
- Plains.Aug.RS: Read sum (sum of number of times this ESVID was counted in this sample) for August plains bison composite samples
- Plains.Aug.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for August plains bison composite sample
- Plains.Jul.RS: Read sum (sum of number of times this ESVID was counted in this sample) for July plains bison composite sample
- Plains.Jul.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for July plains bison composite sample
- Plains.Jun.RS: Read sum (sum of number of times this ESVID was counted in this sample) for June plains bison composite samples
- Plains.Jun.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for June plains bison composite sample
- Plains.May.RS: Read sum (sum of number of times this ESVID was counted in this sample) for May plains bison composite samples
- Plains.May.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter May plains bison composite sample
- Plains.Apr.RS: Read sum (sum of number of times this ESVID was counted in this sample) for April plains bison composite samples
- Plains.Apr.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for April plains bison composite sample
- Plains.Mar.RS: Read sum (sum of number of times this ESVID was counted in this sample) for March plains bison composite samples
- Plains.Mar.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter March plains bison composite sample
- Plains.Feb.RS: Read sum (sum of number of times this ESVID was counted in this sample) for February plains bison composite samples
- Plains.Feb.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for winter February plains bison composite sample
- Plains.Jan.RS: Read sum (sum of number of times this ESVID was counted in this sample) for January plains bison composite samples
- Plains.Jan.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for January, plains bison composite sample
- Plains.Dec.RS: Read sum (sum of number of times this ESVID was counted in this sample) for December plains bison composite samples
- Plains.Dec.RS.mu: Mean of read count (number of times this ESVID was counted in this sample) for December plains bison composite sample
Code/software
Code can be made available upon request to the corresponding author.
Access information
Other publicly accessible locations of the data:
- None
Data was derived from the following sources:
- Elk Island National Park - fecal samples
- Texas A&M Gastrointestinal Laboratory - NIRS
- Jonah Ventures - DNA metabarcoding
We collected fecal samples once every calendar week in both the northern and southern blocks at Elk Island National Park, Alberta, Canada. We started collecting samples in the first week of December 2020 and ended collection during the last week of November 2021. We determined bison locations via global positioning system collar data or via observations by EINP staff. We collected all samples within 6 days of known bison occurrence at a location and then froze the samples. We ensured the freshness of fecal samples by observing bison defecating and collecting the samples after the bison moved away. An EINP employee with expertise in aging bison fecal samples led collection efforts. We collected samples from mixed herds, which included adult females and juveniles, yearlings, and calves of both sexes. We used composite samples to account for potential differences in diet composition and quality between different sexes and age classes (Mooring et al. 2005, Jung 2015). We took approximately 5 mL from the center of 5 fecal samples and combined them to create a composite sample for each date of collection.
We had composite samples sequenced for trnL chloroplast introns at Jonah Ventures (Boulder, Colorado, USA) environmental DNA (eDNA) laboratory (Craine et al. 2015). This eDNA metabarcoding method provides the number of times a trnL sequence is identified in a composite sample (i.e., a read count). Using the sequences provided, we used the Basic Local Assignment Search Tool (BLAST) through the National Center of Biotechnology Information (NCBI) database (Sayers et al. 2021) to identify plants in the bison’s diet. We identified plants to the finest operational taxonomic unit available (e.g., species, genus, family) that had a 99% similarity in trnL sequence from the fecal sample and database (King and Schoenecker 2019) and were known to occur within EINP (EINP, unpublished data). Next, we calculated the relative read abundance (RRA) as the ratio of a read count of a unique taxonomic unit to the total read count within a composite sample. To estimate subspecies and seasonal diets, we calculated the mean RRA for each trnL sequence from the composite samples for each subspecies within the appropriate timeframe. The RRA is an estimate of the proportion of diet of each taxonomic unit that is comparable to other methods estimating diet composition, such as microhistology (Craine et al. 2015, Kartzinel et al. 2015, Deagle et al. 2019, King and Schoenecker 2019). For comparison of subspecies’ diet and modeling of dietary changes throughout the year, we only included taxonomic units that had an RRA of at least 0.5% within a composite sample (Hecker et al. 2021).
To assess differences in diet quality between subspecies and changes in diet quality throughout the year within a subspecies, we used near-infrared reflectance spectrometry (NIRS). This method identifies the chemical structure of a fecal sample using the unique near-infrared spectrum signatures of botanical components in the sample (Norris et al. 1976). The technique has been widely used to assess forage quality in herbivore diets (Walker et al. 2002, André and Lawler 2003, Craine et al. 2013). One of the advantages of this technique is that it is not subject to bias based on differential digestibility of forages (Garnick et al. 2018). We shipped portions of our composite fecal samples to the Grazingland Animal Nutrition Lab (Temple, Texas, USA) for NIRS diet quality analysis. Specifically, we were interested in differences in crude protein (CP), digestible organic matter (DOM), the ratio of DOM to CP (DOM/CP), and fecal nitrogen (FN) content within the subspecies’ diets. These components are key indicators of ruminant diet quality (van Soest 1994).
