Tardigrades are charismatic microinvertebrates that are an important component of the vast ubiquitous microscopic biodiversity that lies hidden all around us. They sometimes reach 1mm in length, but they are usually much smaller. Together with their hyperdiverse but tiny community members, tardigrades live in the soil under our feet, moss and lichens on trees and rocks, and in freshwater and marine benthic habitats from intertidal zones to abyssal depths. Also known as water bears, they have four pairs of lobopodous legs, and with a cuticle that requires molting for growth, they are part of the Superphylum Ecdysozoa with close relatives such as arthropods, onychophorans, and nematodes.

Water bears are sometimes referred to as extremophiles because they can persist under complete desiccation and other environmental extremes and survive for decades via a complex suite of biochemical tricks called cryptobiosis. They have recently enjoyed some acclaim in popular media thanks to being the only animals to survive exposure to space in low earth orbit (Erdmann & Kaczmarek 2016). With rare exceptions, though, only terrestrial tardigrades are capable of cryptobiosis, and since they are not active in times of environmental extremes even these are more accurately termed “extremotolerant.”

Space Water Bear Tattoo @kellymcgrath.art; also see Star Trek: Discovery, Ant-Man I and II, South Park, etc.

Aims of this website

With this website we open a window into the world of tardigrade diversity and thus microscopic biodiversity, in general. It has been said that there is more diversity in the soil than on the soil (Nielsen et al. 2015). Microscopic life seems uncommon and alien simply because we haven’t looked at it much. In this website, we invite you to look deeply at this hidden world. We have three main aims:

   • Provide information to people who are interested in learning more about Tardigrades. We provide a compendium of all of the tardigrade species recorded in North Carolina with pictures of each species, information on species identification, and additional comments such as notable facts and taxonomic issues. County maps of occurrence are provided for each species.

   • Raise awareness of the possibility that microscopic life can be threatened by anthropogenic impacts, just as we know that macroscopic life can be. While no tardigrade species have a designated conservation status, that is quite likely due to ignorance. The idea that small organisms (e.g. microinsects, krill, etc.) are so abundant that conservation is not required, is simply an unsubstantiated bias. We know that many species of tardigrades are rare, and some have quite restricted range distributions. Numerous studies have indicated that tardigrade populations and communities are impacted by humans (Ayers et al. 2008, Giovannini et al. 2018, Hohl et al. 2001, Iglesias Briones et al. 1977, Peluffo et al. 2006, Peluffo et al 2007, Rocha et al. 2016, Vicente 2010, Zepilli et al. 2015). Thus, it is certainly conceivable that tardigrade conservation needs are real, if not currently known. In species accounts, we provide data on abundance, specifically noting rare species when possible.

   • Stimulate further research on tardigrades. On the maps page note that there are very few counties for which tardigrade records currently exist. This illustrates the fact that current county distribution maps are really maps of tardigradologists rather than tardigrades. Most of the state’s tardigrade fauna is completely unexplored. Similarly, the monthly distribution graphs in the species accounts are woefully incomplete. We do not have true seasonality data on any species. In most cases, the county reports are from a very minimal number of samples in very limited locations, habitats, and months. The one exception to this is the multi-year survey conducted by Bartels, his students, and colleagues in the Great Smoky Mountains National Park as part of the All Taxa Biodiversity Inventory. This is one of the largest regional surveys of tardigrades ever conducted, and it was unique in exploring all major habitats (moss, lichen, soil, streams). As a result, the two NC counties in the Smokies (Haywood and Swain) are some of the most thoroughly studied places in the world for tardigrades (Bartels 2005, Bartels & Nelson 2006, 2007, Bartels et al. 2007, 2008, 2009, 2011a, 2011b, 2014, Nelson & Bartels 2012, 2013, Bartels et al. 2014, Bertolani et al. 2014, Gasiorek et al. 2020, Nelson et al. 2020, Stec et al. 2021). Even so, the species from the Smokies inventory are mostly known by name and location only, and with a few exceptions, no DNA analyses have been conducted. Throughout the state many new species await discovery, and in every county rich stories are yet to be told about water bear life history, physiology, ecology and evolution. This website is only a beginning.