The structure of tardigrade communities at fine spatial scales in an Andean Polylepis forest

ABSTRACT

Little is known about distribution patterns of micrometazoan organisms at different spatial scales and the mechanisms driving these patterns across different environments. Here we explore the fine-scale structure of tardigrades in a high-elevation Polylepis forest in northern Ecuador. To investigate spatial patterns of tardigrade abundance, we collected samples from different bryophyte taxa (hosts) on the woodland floor. We identified some tardigrades to species, but most taxa were considered at the level of morphological operational taxonomic units. Tardigrade assemblages differed in composition between host taxa, with some tardigrade taxa associated more with certain hosts, which might relate to host architecture or chemistry. Tardigrade occupancy, richness and abundance varied considerably between samples, and we estimate that more than 50 samples are required to estimate tardigrade taxon richness in this forest habitat. Physical distance between samples was not related to similarity of composition, and it seems that fine-scale differences in environmental conditions (including the distribution of host bryophytes) is much more important in determining tardigrade composition. We conclude that standardised, comprehensive sampling of terrestrial tardigrades at fine scales is necessary before making broader comparisons at coarser geographical scales. Such sampling should account for the diversity of potential hosts, with sufficient replication to capture tardigrade diversity.

KEYWORDS:

• Tardigrada
• bryophyte
• lichen
• diversity
• Andes

Acknowledgments

We are grateful to the QCA Herbarium, the QZNE Museum at the Pontificia Universidad Católica del Ecuador, and the Ecuadorian Ministry of the Environment for the permits to collect the sample material used in this study: Scientific Investigation Authorisation Patent No. 10-2010-FLO-DPAP-MA and Patent No. 009-2015-FAU-DPAP-MA. David Suarez Duque and Segundo Chimbolema provided logistical help in the field.

Disclosure of potential conflicts of interest

No potential conflict of interest was reported by the author(s).

Supplementary material

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Additional information

Funding

The authors did not receive any funding for this work.