High and hardy: Cold‐tolerant generalists inhabit extreme elevations in Rocky Mountain <i>Pardosa</i> spiders

Abstract Evaluating the characteristics that allow species to inhabit high‐elevation environments is central to understanding the historical drivers of montane biogeography and forecasting where species will live as our planet gets warmer. Over the last 200 years of research, two patterns appear widespread: (1) high‐elevation species are usually either specialists that only live in very high elevations or extreme generalists that can live anywhere; and (2) they often possess adaptations to tolerate the cold. Although the factors that underlie species' elevational distributions have been intensively studied in many invertebrate and vertebrate taxa, relatively little is known for spiders. To evaluate if the elevational distributions of spiders align with the common drivers of high‐elevation life, we compiled and analysed an extensive dataset of high‐quality, georeferenced collections of 34 Pardosa species across the Rocky Mountains in Colorado, USA. First, we show that Pardosa species richness declines at the highest elevations. Second, we reveal that most high‐elevation Pardosa species are not specialists. Instead, generalists occur at the most extreme elevations. Finally, we uncover that species found in the highest elevations tend to also inhabit the coldest parts of North America, which suggests that high‐elevation species are likely cold‐adapted. It therefore appears that the elevational distributions of Pardosa spiders in the Colorado Rocky Mountains largely adhere to patterns in other invertebrates and vertebrates. With climate change forcing species to disperse upslope, this work also provides insight into the ways this clade may respond over the coming decades.