Analyzing predator scats for the presence of prey is a common noninvasive approach to understanding trophic interactions. Morphological analysis of prey remains has been the prevailing method of diet analysis, but molecular methods are becoming more widely used. Previous analyses suggest molecular methods detect target prey species more frequently than morphological methods. We compared these methods by analyzing coyote (Canis latrans) scats-collected in Tooele County, Utah, USA, in the winter of 2014-for leporids, a taxonomic group for which a molecular species identification test has been developed. We included 25 scats in which leporids were detected and 25 scats in which leporids were not detected by morphological methods. Additionally, because few studies have explored the effect of fecal sampling protocols on prey DNA detection, we analyzed subsamples taken from 5 locations on each scat to compare prey detection frequencies. We found that molecular analysis detected leporid prey in scats at a rate similar to or greater than morphological analysis, depending on the number of fecal sampling locations considered. Of the single samples, the homogenized (46%) and side (44%) samples provided the greatest rates of leporid prey DNA detection, followed by the ends (mean across both ends ¼ 35%) and center (38%) of scats. When multiple sampling locations were considered, the homogenized-side combination (70%) had a detection rate similar to when all sampling locations were considered (76%). Our results indicate that molecular analysis detected prey more frequently than morphological analysis, but that prey detection was not equitable among fecal sampling locations and multiple sampling locations may be required. Ó 2017 The Wildlife Society.

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Carnivore diet‐selection studies based on scat analyses are frequently used to elucidate predator ecology, predict potential effects on prey populations, and inform management decisions. However, accuracy of results and the following inference are contingent on multiple sources of sampling error including missed detections and pseudoreplication in statistical comparisons that assume independence within scat samples. We compared a repeated‐sampling occupancy framework intended to estimate detection and occurrence rates for diet items with a multinomial modeling approach intended to estimate diet selection while accounting for nonindependence of diet items within samples. Both methods allowed for multimodel inference to specifically test hypotheses about differences in diet. We applied each method to 2 example data sets, a bobcat (Lynx rufus) scat data set (n = 101) collected in western Virginia, USA, from 2011 to 2013 with morphological identification of diet items, and a coyote (Canis latrans) scat data set (n = 50) collected in Tooele County, Utah, USA, in 2014 with molecular identification of diet items, and compared results with those commonly implemented in diet studies (frequency of occurrence calculations). We found imperfect detection of diet items was not a major source of bias in either the morphological or molecular data set results, but grouping similar or indistinguishable diet items in the morphological data set affected estimates when there was heterogeneity in detection among items. Using the occupancy approach on the morphological data set demonstrated that presence or amount of some diet items could decrease detection of other items and bias occurrence estimates. Furthermore, comparing multiple models of bobcat diet using Akaike's Information Criterion with either approach revealed no support for seasonal differences, even though traditional frequency of occurrence calculations differed by almost 10%. Thus, we suggest even moderate trends in diet based on frequency of occurrence calculations without incorporating measures of uncertainty may represent sampling error, and not true differences in diet. When detection is not conditional on other diet items, comparison of multinomial models will typically be sufficient to make accurate inference about carnivore diets without requiring additional processing of scat samples. © 2019 The Wildlife Society.

Urbanization constitutes one of the most aggressive drivers of habitat and biodiversity loss worldwide. However, studies focused on determining the response of local biodiversity to urbanization are still scarce, especially in tropical ecosystems. Urban ecosystems are characterized by low biological productivity which in turn leads to a reduction in biodiversity. However, the responses to urbanization should be species dependent. For instance, changes in the availability of resources can favor certain species with specific characteristics. We assessed the effects of the urbanization process on a bird community in a city located in the Tropical Andes of southern Ecuador, a region widely recognized for its diversity and endemism of birds. We selected three independent localities in each of the four levels of the urbanization gradient in the study area (forest, forest-pasture, pasture, and urban). In each locality, we sampled the bird community by visual and auditory surveys along 1 km transects between 2016 and 2017. We recorded a total of 1,257 individuals belonging to 74 bird species. We evaluated if the responses of richness and abundance of birds are dependent on trophic guild and foraging strata. We found a significant decrease in bird species richness and abundance from forest to urban sites. However, the response of birds was dependent on the trophic guild and foraging strata. Granivorous birds showed a positive response associated with the urbanization gradient while insectivorous birds showed a negative response. Insectivorous birds were more abundant in forest sites and decreased in abundance across the urbanization gradient. We found that the proportion of birds using different foraging strata drastically changed along urban gradient. Forest sites exhibited a bird community using a variety of habitats, but the bird community became simpler toward the most urbanized sites. Our findings showed different effects of urbanization on bird communities. The ugly: urbanization leads to a dramatic reduction in the diversity of birds, which is consistent in cities with different characteristics and ecological contexts. On the other hand, the responses of bird guilds to urbanization are species dependent. Some guilds are positively impacted by urbanization and show increases in species richness and abundance while other guilds are negatively impacted.

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