Data from: Preservation of stable isotope niche dynamics in squamate museum specimens

Natural history museums are invaluable resources for large-scale
ecological and evolutionary studies, but certain ecological traits can be
challenging to recover, particularly from fluid preserved specimens.
Stable isotope analysis is an elegant method for reconstructing the
dietary niche over integrated timescales, and recovering this information
from museum specimens can provide a critical axis of ecological
information for studies of population dynamics through time and space.
However, isotope ratios of tissues are known to be altered by extended
contact with formalin and ethanol. Here, we assess whether intra- and
interspecific variation in isotopic signature, which represent critical
data used to assess metrics of niche diversity, can be reliably recovered
following fluid preservation. We use a broad taxonomic distribution of
squamates to compare niche metrics prior to and eight weeks following a
standard museum preservation process. We could not recover intraindividual
metrics of niche diversity but found that between-individual variation was
not significantly altered, allowing for the reconstruction of community
niche characteristics. We present an example isotopic analysis from museum
specimens representing generalist and specialist Thamnophis garter snake
populations that aligns with empirical estimates of niche width. We also
present several additional analyses on tissue-specific effects,
delipification, and buffer storage, with useful insights for field
collection and downstream analysis decisions.