δ¹³C and δ¹⁵N values measured in tissues of 4 road kill coyotes.

<p>Symbol shades denote type of tissue sampled. Tissues from the same individual are connected by lines with different dash patterns.</p

Comparison of diet quantification methods.

<p>Comparison of the proportional contributions of marine mammals, terrestrial mammals (small, medium and large), birds, reptiles, invertebrates, plants, fish, and non-food material (e.g., gravel/sand) to 12 DNA-verified coyote scats as identified by three methods: frequency of occurrence (white), percent by volume (light gray) and isotopic mixing models (dark gray). Error bars depict one standard error.</p

Illustration of derived diet-to-scat C and N isotope discrimination factors for coyotes.

<p>The routes through diet-to-hair discrimination factors for red foxes (gray arrows) and through wolves (dashed gray arrows) are depicted. In both cases, the first step used our scat-to-hair ε¹³* and ε¹⁵* values (4.1 ± 1.5‰, 0.9 ± 1.3‰, respectively) to convert scat to hair; the dark gray oval surrounding the hair point depicts 1 SD around the enrichment factors. In step 2, we used published diet-to-hair enrichment factors for red foxes (C: 2.6 ± 0.4‰, N: 3.2 ± 0.3‰; [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0174897#pone.0174897.ref026" target="_blank">26</a>]) and wolves (C: 4.25 ± 0.4‰, N: 3.1 ± 0.2‰; [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0174897#pone.0174897.ref027" target="_blank">27</a>]) to convert hair to diet; gray error oval around the diet points depict the propagated standard deviation. Finally, in step 3, we calculated the values necessary to convert from diet to scat.</p

Scat stable isotope sampling rationale.

<p>Step 1 is to separate the coyote scat—the fine-grained material binding the scat together—from the clearly undigested scat components. In step 2, the undigested materials are identified to the finest taxonomical level possible. In step 3, we conduct stable isotope analyses of both the coyote (scat matrix) and its known diet (identified undigested material). After correcting scat values for diet-to-scat discrimination, we expect that they should fall within the mixing space created by known dietary items.</p

List of coyote carcasses examined and tissues sample.

<p>List of coyote carcasses examined and tissues sample.</p

Scat isotope results.

<p>Carbon and nitrogen isotope values (δ¹³C and δ¹⁵N) measured in twelve coyote scats (corrected for discrimination; open circles) from Año Nuevo State Park, CA, plotted in reference to isotope values measured in dietary components found in the scat.</p

Apparent C and N isotope enrichment factors among sampled tissues of road kill coyote carcasses.

<p>Apparent C and N isotope enrichment factors among sampled tissues of road kill coyote carcasses.</p

Data_Sheet_1_Climate and vegetation and their impact on stable C and N isotope ratios in bat guano.zip

Cave guano deposits represent a relatively untapped paleoecological archive that can provide information about past vegetation, climate, and bat diet over several millennia. Recent research suggests that carbon isotope values (δ13C) measured in guano accumulations from insectivorous bats reflect the relative abundance of C3 and C4 plants on the landscape while nitrogen isotope values (δ15N) may reflect precipitation amount. Together, these proxies can provide useful information for restoration practitioners seeking to understand how plant species composition has changed over time in relation to climate and land use. To better calibrate these proxies for use in restoration, we compared instrumental records of precipitation and satellite imagery of vegetation with isotope values measured in modern bat guano from Mary Lawson Cave, a large limestone cavern located in central Missouri. Mary Lawson Cave hosts a maternity colony of insectivorous gray bats (Myotis grisescens), and as such, contains significant guano accumulations. In the fall of 2018, we collected a 60 cm long guano core that dates to 1999 cal AD at its base. Guano core δ13C values decrease from the base toward the surface (from ~-26 to -27‰) whereas δ15N values increase toward the surface even after accounting for ammonia volatilization (from ~3 to 5‰). Presently, the landscape around Mary Lawson Cave is dominated by a deciduous forest and pasture. Given that the land cover has changed very little over this period, the decline in δ13C values toward the present likely reflects a shift in land management on farms and/or increases in invasive C3 species. Rainfall amounts from nearby Lebanon, Missouri, are significantly positively correlated with guano δ15N values, a relationship that is notably opposite that observed previously in soil and plants. We argue that heavy fertilizer application and significant grazing intensity could lead to the accumulation of large pools of excess labile nitrogen which would be vulnerable to leaching during precipitation events. The relationship between guano δ15N values and precipitation may differ for materials from less agriculturally impacted locations or periods and should be extended into the past with caution.</p