Esther S. Rubin, Dave Conrad, Larisa E. Harding, Brianna M. Russo
{"title":"Associations between a feral equid and the Sonoran Desert ecosystem\u0000 Asociaciones Entre un Equino Salvaje y el Ecosistema del Desierto Sonorense","authors":"Esther S. Rubin, Dave Conrad, Larisa E. Harding, Brianna M. Russo","doi":"10.1002/wmon.1083","DOIUrl":"https://doi.org/10.1002/wmon.1083","url":null,"abstract":"<p>The effect of non-native herbivores on ecosystems and diversity has become a global concern in conservation. Management challenges associated with non-native free-roaming equids have existed for decades in a wide range of ecosystems yet have been difficult to resolve. Although much of the challenge is associated with non-biological considerations, empirical ecological research is crucial for guiding sound management decisions. We conducted a field study on the associations between feral burros (<i>Equus asinus</i>) and elements of the Sonoran Desert ecosystem in Arizona, USA, during 2017–2019. We identified areas with and without established burro herds, and collected data on vegetation, ungulate sign, small mammals, birds, and herpetofauna at multiple, randomly selected grids within these areas, while accounting for vegetation community and distance to water. We predicted that burros would be associated with differences in vegetation metrics such as lower ground cover, smaller perennial plant size, and lower plant density, foliage density, recruitment, and species richness among perennial native plants susceptible to burro foraging or trampling. We further predicted that these differences would be accompanied by lower density or relative abundance and lower species richness of small mammals, birds, and herpetofauna. Finally, because burro distribution has been documented to be associated with water in this arid landscape, we predicted that effects would be most pronounced near water. The results of our study did not consistently support our predictions, perhaps because of small sample sizes or, in several cases, inherent complexities associated with seasonal burro habitat use and plant phenology patterns. However, our study documented that the presence of this feral equid is associated with a number of key differences that may be ecologically important and have the potential to alter community structure in this sensitive arid ecosystem. In areas with established burro herds, we documented lower ground cover, plant density, foliage density, or smaller plant size in several species, and changes were often influenced by distance from water. For example, density of Engelmann's prickly pear cactus (<i>Opuntia engelmannii</i>) was 94% lower and Anderson wolfberry (<i>Lycium andersonii</i>) plants were 49% smaller in areas with established burro herds. In areas with burros, we also recorded lower density of white bursage (<i>Ambrosia dumosa</i>) in areas distant from water. Of notable concern was that our metric of recruitment indicated 63% lower recruitment in saguaro cactus (<i>Carnegiea gigantea</i>) and that foliage densities of yellow paloverde (<i>Parkinsonia microphylla</i>) and desert ironwood (<i>Olneya tesota</i>) were lower in areas with established burro herds. Data on some plant species did not support our predictions. For example, white bursage and Anderson wolfberry plants were found at similar densities in areas with and without esta","PeriodicalId":235,"journal":{"name":"Wildlife Monographs","volume":null,"pages":null},"PeriodicalIF":4.3,"publicationDate":"2024-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/wmon.1083","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141488851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}