DOI: 10.5061/dryad.0p2ngf1zn
title: Data for: Microclimate structures communities, predation and herbivory in the High Arctic

description:   In a warming world, changes in climate may result in
 species-level responses as well as changes in community structure through
 knock-on effects on ecological interactions such as predation and
 herbivory. Yet, the links between these responses at different levels are
 still inadequately understood. Assessing how microclimatic conditions
 affect each of them at local scales provides information essential for
 understanding the consequences of macroclimatic changes projected in the
 future.  Focusing on the rapidly changing High Arctic, we examine
 how a community based on a common resource species (avens, Dryas
 spp.), a specialist insect herbivore (Sympistis zetterstedtii), and
 natural enemies of lepidopteran herbivores (parasitoids) varies along a
 multidimensional microclimatic gradient. We ask (1) how parasitoid
 community composition varies with local abiotic conditions, (2) how the
 community-level response of parasitoids is linked to species-specific
 traits (koino- or idiobiont life cycle strategy and phenology) and (3)
 whether the effects of varying abiotic conditions extend to interaction
 outcomes (parasitism rates on the focal herbivore and realized herbivory
 rates).  We recorded the local communities of parasitoids,
 herbivory rates on Dryas flowers and parasitism rates
 in Sympistis larvae at 20 sites along a mountain slope.
 For linking community-level responses to microclimatic conditions with
 parasitoid traits, we used joint species distribution modelling. We then
 assessed whether the same abiotic variables also affect parasitism and
 herbivory rates, by applying generalized linear and additive mixed models.
 We find that parasitism strategy and phenology explain local variation in
 parasitoid community structure. Parasitoids with a koinobiont strategy
 preferred high-elevation sites with higher summer temperatures or sites
 with earlier snowmelt and lower humidity. Species of earlier phenology
 occurred with higher incidence at sites with cooler summer temperatures or
 later snowmelt. Microclimatic effects also extend to parasitism and
 herbivory, with an increase in the parasitism rates of the main
 herbivore S. zetterstedtii with higher temperature and
 lower humidity, and a matching increase in herbivory rates.  Our
 results show that microclimatic variation is a strong driver of local
 community structure, species interactions and interaction outcomes in
 Arctic ecosystems. In view of ongoing climate change, these results
 predict that macroclimatic changes will profoundly affect arctic
 communities.   
description: This dataset comprises of parasitoids caught during summers 2015
 and 2015 at 20 sampling sites distributed at different elevations and
 snowmelt charasteristics near the Zackenberg research stations in
 North-East Greenland. All sites were of Dryas heath habitat, characterised
 by Dryas octopetalaXintegrifolia dominated vegetation. Trapping of
 parasitoids was done using 10 open sticky traps (5cm by 4.5cm white sticky
 traps cut out from sticky board: Barrettine Environmental, UK [product no
 longer available]) and 5 emergence traps (with a half a square metre
 footprint) placed on Dryas tussocks.  The traps were emptied every six
 days 4 sites a time in a rolling schedule. The
 parasitoids were subsequently picked of off the sticky traps, their whole
 DNA was extracted and half of their Cytochrome Oxidase I barcode region
 was amplified using Primers B-F and HCO. See the supplementary information
 of the publication for more details. The dual tag indexed library of
 parasitoid samples was sequenced at the FIMM Technology Centre in a
 HiSeq2500 2x250bp run. Additionally, each year, roughly
 50 larvae of noctuid moth Sympistis zetterstedtii were collected from
 around each sampling site by hand and also though sticky trapping. The
 whole DNA of these larvae was sequenced and parasitoid barcode sequences
 were amplified while suppressing the amplification of lepidopteran
 sequences using a species specific blocking primer. 
 Dryas flower numbers, flowering phenology and flower damage by
 insect herbivores was recorded during every visit to the sites. These
 counts were done in 5 square metre monitoring plots per trapping
 site.  Microclimate was recorded at trapping sites
 using Lascar EL-USB-2 tempeerature and air humidity loggers under a small
 white plastic dome at ~ 10 cm height.
description: The accompanying file README_ZackenbergParasitoids.txt contains
 information on all files and columns of data in this dataset as well as
 additional information on the dataset.