DOI: 10.5061/dryad.sxksn03bb
title: Supplementary information from: A systematic review of trace elements in the tissues of bats (Chiroptera)

description: Bats constitute about 22% of known mammal species; they have various
 ecological roles and provide many ecosystem services. Bats suffer from
 several threats caused by anthropization, including exposure to toxic
 metals and metalloids. In our systematic review, we analyzed 75 papers to
 investigate how species, diet, and tissue type impact bioaccumulation in
 bat species all over the world. Most studies documented element
 accumulation in fur, liver, and kidney; at least 36 metals and metalloids
 have been measured in bat tissues, among the most studied were mercury and
 zinc. Comparisons with known toxicological thresholds for other mammals
 showed concerning values for mercury and zinc in bat hair, lead and some
 essential metals in liver, and iron and calcium in kidneys. Moreover,
 accumulation patterns in tissues differed depending on bat diet:
 insectivorous bats showed higher metal concentrations in fur than in liver
 and kidney while frugivorous species showed higher values in liver and
 kidney than in fur. This review points out several information gaps in the
 understanding of metal contamination in bats, including a lack of measured
 toxicity thresholds specific for bat tissues. Data on trace element
 bioaccumulation and its associated health effects on bats is important for
 conservation of bat species, many of which are threatened.
description: The literature search was performed using Google Scholar and Web
 of Science Core Collection (Clarivate) during the period of 1978 to 2021,
 using keywords/Boolean operators: “bats” and/or “metal” and/or
 “contamination” and/or “fur” (title). A total of 75 publications from the
 1978-2021 period were located and included in this review, including
 peer-reviewed papers and unpublished reports. Metadata collected from 67
 scientific papers (reviews excluded) included: species, sample size,
 tissue, geographic location, age, sex, diet type, and trace element
 content. Element concentrations in bat tissues were converted from a wet
 weight to a dry weight by multiplying the wet weight value by a factor of
 3.7 for liver, 3.9 for kidney, and 4.0 for fur and all the other analyzed
 tissues; these factors were calculated according to the moisture content
 of the specific organ. No such conversion was made when dry weights were
 provided. Data analysis included: metals (Ag, Al, Ba, Be, Ca, Cd, Cr, Co,
 Cu, Fe, Hg, K, Li, Mg, Mn, Mo, Na, Ni, Pb, Rb, Sn, Sr, Th, Ti, Tl, V, W,
 Y, Zn, Zr), metalloids (As, Si), and nonmetals (Ar, Br, O, Se), in various
 tissues (fur, liver, kidney, whole body, bone, brain, blood, stomach,
 muscle, heart, wing, lungs, patagium, spleen, gut), and excrement
 (guano).  Tissue burdens of trace elements were compared among the bat
 diet categories (insectivores, frugivores, nectarivores, and other). All
 trace element concentrations for bats provided in every article were
 pooled by element, and log-transformed prior to statistical analysis. Four
 bat species (<em>Eptesicus fuscus</em>, <em>Myotis
 daubentonii</em>,<em> Myotis lucifugus</em>, and
 <em>Myotis myotis</em>) have been subject of multiple studies;
 it was possible to perform comparative statistical analyses on tissue
 concentrations among these species. A meta-analysis of
 published data was carried out for metal concentrations among bat tissues,
 species, and diet categories. The following statistical analyses were
 performed. Normality tests
 (Kolmogorov-Smirnov, Shapiro-Wilk, Anderson-Darling, Lilliefors, and
 Jarque-Bera) were conducted for each data set (i.e., for every metal in
 each tissue, species, and diet category), to establish whether data
 distributions were normal. Significance was set at p = 0.05.
 For normally distributed data, a
 parametric test (One-way ANOVA) was performed to compare each element’s
 concentration among different tissues, species, or diet categories,
 followed by a Tukey test (with a confidence interval of 95%) and an REGWQ
 test to determine the specific differences among the categories.
 For non-normally distributed data, a
 Kruskal-Wallis test was applied to compare each metal’s concentration
 between tissues, species, or diet categories, followed by a Dunn’s
 procedure to compute multiple pairwise comparisons, and a Bonferroni
 correction to avoid redundancy bias.
description: # Supplementary Information: A systematic review of trace elements in the
 tissues of bats (Chiroptera)
 [https://doi.org/10.5061/dryad.sxksn03bb](https://doi.org/10.5061/dryad.sxksn03bb) ## Description of the data and file structure This dataset was born as an Appendix to our manuscript "A systematic review of trace elements in the tissues of bats (Chiroptera)". In our systematic review, we analyzed 75 papers to investigate how species, diet, and tissue type impact bioaccumulation in bat species all over the world. The present dataset contains the following information: a taxonomic table with all the bats families and genera investigated (A.1), reference tables comprehensive of sample sizes, concentration values ±SD, and meaning of values for each trace element in each tissue (A.2 to A.16) and in each species (A.17 to A.20) investigated, a table with all the bat species considered organized by their diet preference (A.21), visual data on concentrations in bat tissues/species not shown in the main manuscript (B.1.1 to B.2.2.), and the results from statistical analyses (pairwise comparisons, multiple pairwise comparisons, and Kruskal-Wallis tests) comparing concentrations among different bat tissues and diet types (C.1.1. to C.2.12). Appendix D contains a descriptive summary of the results of 19 studies on the topic of trace element contamination in bats published from 2021 to 2024, and not included in the meta-analysis of the main manuscript. The final reference list contains all the articles consulted for the review.