Biodiversity Data Journal :
Research Article
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Corresponding author: Robert E Clark (robert.e.clark@wsu.edu)
Academic editor: Brian Lee Fisher
Received: 10 Mar 2021 | Accepted: 16 Apr 2021 | Published: 10 May 2021
© 2021 Kayla Dilworth, Marek Borowiec, Abigail Cohen, Gabrielle Mickelson, Elisabeth Oeller, David Crowder, Robert Clark
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Dilworth KA, Borowiec ML, Cohen AL, Mickelson GS, Oeller EC, Crowder DW, Clark RE (2021) Ants of the Palouse Prairie: diversity and species composition in an endangered grassland. Biodiversity Data Journal 9: e65768. https://doi.org/10.3897/BDJ.9.e65768
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Grasslands are globally imperilled ecosystems due to widespread conversion to agriculture and there is a concerted effort to catalogue arthropod diversity in grasslands to guide conservation decisions. The Palouse Prairie is one such endangered grassland; a mid-elevation habitat found in Washington and Idaho, United States. Ants (Formicidae) are useful indicators of biodiversity and historical ecological disturbance, but there has been no structured sampling of ants in the Palouse Prairie. To fill this gap, we employed a rapid inventory sampling approach using pitfall traps to capture peak ant activity in five habitat fragments. We complemented our survey with a systemic review of field studies for the ant species found in Palouse Prairie. Our field inventory yielded 17 ant species across 10 genera and our models estimate the total ant species pool to be 27. The highest ant diversity was found in an actively-managed ecological trust in Latah County, Idaho, suggesting that restoration efforts may increase biodiversity. We also report two rarely-collected ants in the Pacific Northwest and a microgyne that may represent an undescribed species related to Brachymyrmex depilis. Our score-counting review revealed that grassland ants in Palouse Prairie have rarely been studied previously and that more ant surveys in temperate grasslands have lagged behind sampling efforts of other global biomes.
Palouse Prairie, ant biodiversity, rapid species inventory, agroecosystems, insect conservation, prairies
Temperate grasslands and savannah are amongst the most endangered biomes in the world, having the highest rate of conversion to agriculture and the lowest rate of government protection (
Biodiversity surveys play a strategic role in grassland conservation, aiding arguments that habitats contain rare or endemic species (
The Palouse Prairie is an endangered grassland ecosystem that originally encompassed south-eastern Washington State and neighbouring northern Idaho (
Published biodiversity surveys are limited for the Palouse Prairie, encompassing a survey of bumblebees (
Ant surveys were completed at five prairie fragments: Hudson Biological Reserve, Kamiak Butte County Park, Skinner Ecological Preserve, Idler’s Rest Nature Preserve and Philips Farm County Park (Figs
Species-level identification of ants can be time-consuming and difficult in regions with poorly-described ant fauna (reviewed in
We searched for studies in Web of Science that quantified abundance or richness of the ant species within prairie or grassland from 2016 to the present. Our search was conducted in June 2020 using the term “ant AND divers* AND prairie OR ant AND divers* AND grassland”. Our search yielded 106 studies that were reviewed for inclusion, based on three criteria: (i) the study assessed more than one species; (ii) the study was performed in non-agricultural grassland or prairie; and (iii) the biome of the study could be determined; 21 studies met these criteria (Suppl. material
We examined the frequency of recent publications on each individual species collected in our pitfall survey using the same approach as the biome survey, but instead used the genus and species names as search terms. We tabulated the number of studies from 2010-2020 that reported ant species we found. We read abstracts to ensure that all studies included in this survey involved field observations of the insect species in question and we included multiple species names for recently-revised species (
Analyses and figure generation were completed in R ver 4.0.2 (
Amongst all sites, we collected 17 ant species (Table
Studies reporting species found in this survey between, published 2010 and 2020.
Ant species | Studies | Paper References |
Aphaenogaster occidentalis | 1 |
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Brachymyrmex depilis | 3 |
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Brachymyrmex sp. microgyne | 2 |
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Camponotus vicinus | 1 |
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Formica argentea | 2 |
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Formica lasioides | 1 |
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Formica neoclara | 0 | |
Formica neogagates | 5 |
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Formica puberula | 0 | |
Formica subaenescens | 0 | |
Lasius americanus, reported as Lasius alienus in older works | 11 |
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Prenolepis imparis | 13 |
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Solenopsis molesta | 4 |
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Tapinoma sessile | 20 |
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Temnothorax nevadensis | 1 |
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Temnothorax rugatulus | 11 |
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Tetramorium immigrans and Tetramorium caespitum | 23 |
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Ant species richness varied amongst sites, with the highest diversity at Skinner Ecological Preserve (Fig.
We found 95 publications detailing a study containing at least one species observed in our survey (Table
Our model results suggest there are likely many more ant species to be discovered with more intensive sampling in Palouse Prairie and that there is likely to be appreciable diversity of other insect species beyond those of the limited taxonomic focus of this study. Furthermore, one of our collected specimens may be a currently undescribed species of ant, but this putative ant species is rarely collected and taxonomic revision of Brachymyrmex is required to demonstrate if this is the case. In many ecosystems, insect faunas are poorly described (
Ant communities are under-sampled in cool-temperate ecosystems compared to the tropics and sub-tropics, including temperate grasslands in the north-western United States (
Research in conservation biological control has shown the value of ants as predators in agroecosystems (
The remaining habitat in the Palouse is highly fragmented and only protected by a range of public and private trusts (
KAD, ALC, ECO and REC completed field surveys. REC analysed data. KAD, ALC, GSM and ECO performed the systematic review. KDA, REC and MLB curated and identified ants. All authors contributed to writing and editing the manuscript.
The authors declare no conflicts of interest.