Pack rats (Neotoma spp.): Keystone ecological engineers?

Walter G. Whitford, Yosef Steinberger

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


The potential role of two species of pack rats (Neotoma albigula and Neotoma micropus) as keystone ecological engineers was examined by estimating the species diversity of invertebrates living in the nest middens, and nitrogen mineralization rates in soils associated with the middens. Although pack-rat middens in tarbush (Flourensia cernua) shrublands were smaller than those in creostebush (Larrea tridentata) shrublands, they housed a higher abundance and diversity of arthropods. The Neotoma spp. middens were an important microhabitat for crickets (Gryllus sp.), wolf spiders (Lycosa spp.), and lycid beetle larvae (Lycidae) in all of the shrub habitats. There were five arthropod taxa that occupied all middens in the creosote-bush shrubland, and 12 arthropod taxa that occupied all middens in the tarbush shrubland. Soils associated with pack-rat middens had significantly higher soil organic-matter content than reference soils. Nitrogen mineralization was significantly higher in soils associated with pack-rat middens than in reference soils. Neotoma spp. create habitats with moderate microclimates that are essential for several invertebrates, thus contributing to maintenance of biodiversity. The effects of middens on soil organic matter and nitrogen mineralization create nutrient-rich patches. Neotoma spp. affect biodiversity and critical ecosystem processes, thus supporting the designation of keystone ecological engineers.

Original languageEnglish
Pages (from-to)1450-1455
Number of pages6
JournalJournal of Arid Environments
Issue number11
StatePublished - Nov 2010

Bibliographical note

Funding Information:
This research was funded in part by the NSF Long Term Ecological Research Program and by the International Arid Lands Consortium. The funding sources were not involved in the research or preparation of this article. The field work could not have been conducted without the efforts of Heidi Jochem and Matt Flowers.


  • Habitat
  • Mineralization
  • Species diversity
  • Stick nest
  • Woodrat


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