DOI: 10.5061/dryad.sn02v6xdb
title: Effects of herbivory by a translocated butterfly on plant size and seed set of Lonicera involucrata

description: Assisted migration consists of the introduction of a species to previously
 inhabited areas or to new suitable regions. Such introductions have been
 touted as a viable tool for conserving earth's biodiversity. However,
 both the likely success of assisted migrations and the impacts on local
 communities are hotly debated. Empirical data on the local impacts of
 assisted migration are particularly lacking. We examined the short and
 long time-scale effects of herbivory on Lonicera involucrata (Richards)
 Banks ex. Spreng (Caprifoliaceae) after an introduction of Euphydryas
 gillettii Barnes (Lepidoptera: Nymphalidae: Melitaeini) to Gunnison
 County, Colorado via an assisted migration in 1977. The plant is the
 primary larval hostplant for the butterfly. We quantified plant seed
 production, plant survival, and population stage structure in two sets of
 observational experiments. We found that herbivory by E. gillettii
 increased L. involucrata reproduction on an annual time scale, independent
 of plant size and local microhabitat characteristics. Over the time since
 the butterfly’s introduction, herbivory by E. gillettii resulted in a
 plant population structure biased towards smaller plants in the butterfly
 introduction and satellite sites compared to sites without the butterfly.
 Our results highlight the importance of studying effects of assisted
 migrations on native populations at different temporal scales. As assisted
 migration becomes an indispensable tool for species conservation, our work
 adds to the understanding of the multi-trophic impacts of assisted
 introductions on local populations and communities.
description: <em>Euphydryas gillettii</em> was introduced to a
 1.75 ha site at the Rocky Mountain Biological Laboratory (RMBL) in
 Gunnison County, Colorado USA (38°57′5” N, 106°59′6” W, 2912 m asl) in
 1977<em> </em>from Granite Creek, Wyoming USA (43°41’42” N,
 110° 26’55” W, 2130 m asl) (Holdren & Ehrlich, 1981). The
 introduction site is south of the native range.  The
 short-term effects of <em>E. gillettii</em> herbivory on
 <em>L. involucrata</em> were studies at the original butterfly
 introduction site (“Main”) at RMBL (Holdren and Ehrlich 1981) and a 0.75ha
 site (“Avalanche”), located 0.6 km southeast of Main. Avalanche was
 naturally colonized by the butterfly in 2002 (Boggs et al., 2006). We
 marked 78 <em>L. involucrata</em> individuals in Main and 9
 plants in Avalanche with forestry flagging and aluminum metal tags. For
 each plant, we recorded the number of <em>E. gillettii</em>
 larval webs present in early September 2004 as the larvae were entering
 diapause, along with evidence of herbivory by animals other than
 <em>E. gillettii</em>. In 2004, we recorded plant parameters
 that are correlated with the likelihood of <em>E. gillettii
 </em>herbivory on <em>L. involucrata </em>(Bonebrake et
 al., 2010). These included exposure of the plant to sun, (1 = morning, 2 =
 afternoon, 3 = both), soil wetness in the first half of July and early
 September (1 = dry surface, 2 = moist surface, 3 = standing water), and
 presence or absence of <em>P. engelmannii </em>within 1 m of
 the plant. The index of soil wetness used in the analysis was the mean of
 the July and September values. In addition, we recorded measures of plant
 size: total number of shoots in 2004 and plant volume in 2004 and 2005.
 Plant volume was calculated as a rectangular cube, based on plant height,
 plant width and plant length measured with a measuring tape.In 2005, we
 collected all ripe fruits from each marked plant and counted the number of
 seeds. Occasionally, seed dispersers collected the fruits before we did,
 as evidenced by scars present on the base of the bracts. We had earlier
 recorded aborted fruits on each plant, so we could determine whether the
 scar represented aborted or dispersed fruits. For cases of missing fruits,
 we recorded the number missing and estimated total seed set by the plant
 based on the average for other fruits on that plant. To
 examine long-term effects of larval herbivory on individual plants and
 plant population size structure, we used three additional sites without
 <em>E. gillettii</em>. All five study sites contained similar
 vegetation. Both the Main and Avalanche experimental sites consisted of
 east-facing meadows with beaver ponds and streams at the base of Gothic
 Mountain. The Avalanche site lacked the <em>Picea
 engelmannii</em> trees present in the Main site, due to high
 avalanche activity. The three control sites without butterflies were Trail
 401, Copper Creek and North Main. The North Main site was on the same
 east-facing slope of Gothic Mountain as Main and Avalanche. Trail 401 and
 Copper Creek consisted of montane meadows, which were drier and at
 slightly higher elevation than the other three sites. Within each of these
 five sites we randomly selected 2 to 4 10m x 10m subsites, depending on
 the size of the site, with a total of 7 subsites in the treatment and
 seven in the control sites.<em> </em>On July 6-8, 2011, we
 collected data on all <em>L. involucrata</em> individuals in
 each of the long-term study subsites. Using a tally-counter, we separately
 recorded the number of live and dead shoots on an individual plant. Since
 <em>L. involucrata</em> has rhizomes, individual plants were
 denoted as shoot clusters that were located within 15cm of each other. We
 assigned each <em>L. involucrata</em> individual to a size
 class based on its live shoot count. Most plants with less than 10 live
 shoots had no dead shoots, and plants with less than 25 shoots typically
 were not flowering. Therefore, the first two size classes encompassed
 plants containing 1–10 and 11–25 live shoots. We arbitrarily delineated
 the next three size classes to include plants having 26–150, 151–500, and
 greater than 500 live shoots. We recorded instances of flowering, number
 of dead shoots, large mammal or insect herbivory, and whether the
 perimeter of the leaves was slightly reddened, indicating a pathogen
 infection. Based on the surrounding topography and the position and path
 of the sun, we assessed whether the plant received morning or afternoon
 sunlight. We classified the soil around each plant according to the soil
 wetness scale described above. Using a measuring tape or stick, we
 recorded the standing height of each <em>L. involucrata</em>
 plant to the nearest centimeter. Additionally, we approximated the height
 of the tallest surrounding vegetation, excluding <em>P.
 engelmannii</em>, to the nearest 0.5m. We estimated the percent
 cover of any vegetation within a meter that was taller than the
 <em>L. involucrata</em> individual and noted the presence and
 estimated height of any <em>P. engelmannii</em> within 1m of
 the plant.
description: # Effects of herbivory by a translocated butterfly on plant size and seed
 set of Lonicera involucrata
 [https://doi.org/10.5061/dryad.sn02v6xdb](https://doi.org/10.5061/dryad.sn02v6xdb) There are two files. The first contains the 2004/2005 data, and the second contains the 2011 data. Data from the 2004/5 set were used to evaluate the short-term effects of the presence of the introduced butterfly *Euphydryas gillettii* on the reproduction of its larval hostplant *Lonicera involucrata*. Data from the 2011 set included sites with and without the butterfly and were used to evaluate the long-term effects of the butterfly on plant population size structure. Data included in the 2004/2005 set include: plant identification #, # seeds produced in 2004 and 2005, plant volume in 2004 and 2005, total live meristems, sun exposure, presence of spruce, soil moisture, and # of larval webs in 2004 Data included in the 2011 set include butterfly presence/absence, site, subsite, plant identification #, # of live meristems, # of dead meristems, plant size class, plant height, herbivory by animals other than *E. gillettii*, flowering status, sun exposure, soil wetness, surrounding vegetation height, % plant cover, and presence/absence of spruce. ## Description of the data and file structure For 2004/2005: Blank fields under # seeds mean that no data were collected, not that no seeds were produced. codes for 2011 only: butterfly presence/absence: 0=butterfly absent, 1= butterfly present size class is defined in the methods flower status: 0 = no flowers, 1 = flowers present sunburn: 0 = no red on leaves (no leaf pathogen), 1= some red on leaves (leaf pathogen present) codes for both files: sun: 0= no sun received by the plant, 1= morning sun only, 2= afternoon sun only, 3= morning and afternoon sun spruce: 0 = absent, 1 = present soil: index runs from 0-3 as dry to standing water #### Sharing/Access information * Data were collected *de novo*.