Publication Date
2022
Journal or Book Title
Ecological Indicators
Abstract
Methods used to assign rarity among species are fundamental to our ecological understanding and conservation of species that are most vulnerable to extinction or extirpation. Bees (Hymenoptera: Apoidea: Anthophila) are at the forefront of declines in pollinator diversity and a comprehensive understanding of their conservation requirements in any landscape is essential. Rarity is generally defined in terms of numerical abundance and geographical distribution, though aspects of species life history, such as degree of specialization and taxonomic relatedness, are also widely recognized as important. Incomplete information on the life histories of many taxa obliges ecologists to rely on species-level classifications of specialization provided by expert opinion or in published site- or region-specific studies. Descriptions of specialization are therefore rooted in characterization of the habitat and introduce subjectivity into rarity calculations through assumptions of how species perceive and use resources. An alternative approach that may reduce this level of subjectivity is to incorporate important life-history elements into species rarity assessments, which are traits of the organism itself and not its environment. Phylogenetic and functional originality are metrics which have been presented as useful for characterizing the uniqueness of species, and thus for developing a more informed index of species rarity. This study describes our Species Originality and Rarity Index (SpORtI) for bees that includes variables reflecting five rarity and originality metrics for each species: numeric rarity, geographic rarity, phenological rarity, phylogenetic originality, and functional originality. We compared species-specific rarity weights generated with this approach against other indices using a bee dataset collected over three years across the 520,000-km2 land area of the Great Lakes Basin and within the United States and found that rankings using our approach differed significantly from other indices. Our index represents an improvement on previous approaches since it incorporates key information identified by other researchers and avoids potential subjectivity associated with assigning habitat specialization. Importantly, SpORtI has the added advantage to incorporate updated species life-history traits reported in the literature to allow for the most comprehensive and timely rarity index. This new index will aid researchers and practitioners in determining what species to focus conservation efforts on, as well as which management treatments and environmental factors affect our most vulnerable species of bees, or other taxa, so that limited resources can be applied to focal areas of conservation concern more effectively and efficiently.
DOI
https://doi.org/10.1016/j.ecolind.2022.109339
Volume
143
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
License
UMass Amherst Open Access Policy
Recommended Citation
Cunningham-Minnick, Michael; Milam, Joan; and King, David I., "SpORtI: The species originality and rarity index combines phylogenetic and functional originality with rarity metrics to provide a new perspective on species rarity" (2022). Ecological Indicators. 465.
https://doi.org/10.1016/j.ecolind.2022.109339