Caruthers and Debinski: Montane Meadow Butterfly Species Distributions in the Greater Yel 85 MONTANE MEADOW BUTTERFLY SPECIES DISTRIBUTIONS IN THE GREATER YELLOWSTONE ECOSYSTEM + JENNET C. CARUTHERS + DIANE D EBINSKJ ECOLOGY, EVOLUTION & 0RGANISMAL B IOLOGY + IOWA STATE UNIVERSITY + AMES + ABSTRACT 2006; Parmesan, 2006). They are thought to be good indicators because they play important The composition of butterfly roles within different functional groups, commumhes is a good indicator of changing including herbivores, pollinators, and prey and environmental conditions. Butterflies have tight their distribution patterns are correlated with associations with the plant community due to habitat diversity (Scalercio et al. , 2006). their dependence on plants throughout their life Conservation concerns have been heightened by history. These associations make butterfly long-term studies in Europe that have shown distributions predictable based on the plant butterfly communities to be declining (Thomas communities. Butterfly abundance data have and Albery, 1995; Grill and Cleary, 2003; and been collected annually since 1997 within Binzenhofer et al. , 2005). Understanding what is montane meadow sites characterized along a causing this decline could lead the way to hydrologic gradient within the Greater uncoupling the loss of species diversity and Yellowstone Ecosystem. From this research, protecting the diversity of other taxa that share community composition may be predictable the butterfly habitat. relative to future climatic changes and key habitat constraints. Identifying such variables is There are many factors that have been important for butterfly conservation. identified to have a negative effect on butterfly communities. Loss of suitable habitat is one of the most threatening factors for butterfly species + INTRODUCTION AND OBJECTIVES persistence (Grill and Cleary, 2003). Changes in habitat suitability due to climatic variations can Butterfly communities have been also affect butterfly abundance (Ockinger et al. , established in the literature as well known 2006). The pristine nature and minimal human indicators for environmental changes (Debinski impacts in the Greater Yellowstone Ecosystem and Brussard, 1994; Gutierrez and Menendez, make it an ideal location for studying the effects 1998; Simonson et al. , 2001 ; Dennis et al., 2006; of climate driven variation on butterfly Scalercio et al. , 2006). Butterfly species richness communities. can be predicted from models using landscape variables such as elevation and topographic In this study we hope to determine heterogeneity (Nally et al. , 2003) and plant whether the butterfly communities in the Greater richness (Field et al. , 2006). Butterflies have Yellowstone Ecosystem fluctuate predictably been used to predict areas that represent hotspots relative to alterations of climate driven changes of biological diversity (Simonson et al. , 2001) along a hydrologic gradient in the landscape. and they may serve as good indicators of climate Climate driven variables include temperature and change (Debinski et al. , 2000; Debinski et al. , precipitation fluctuations, and the effects of such changes on species of forbs that serve as host Published by Wyoming Scholars Repository, 2006 1 University of Wyoming National Park Service Research Center Annual Report, Vol. 30 [2006], Art. 14 86 plants and nectar resources for butterflies in this minimum of 100 m by 100 m and no more than 2 ecosystem. Shallow-rooted forbs are expected to km on a side, as well as at least 500 m from be especially affected by an increase in another meadow site (Debinski et al. , 2001). temperature (Devalpine and Harte, 2001 ; and Saavedra et al. , 2003; Cross and Harte, 2007) Field Surveys and a decrease in precipitation (Weaver, 1958) and we hypothesize that these changes will be Field surveys were conducted during reflected in butterfly abundance of the species June through August for two week periods at that use these forbs for host plants or nectar. each region, alternating between the two regions. Stability in the butterfly community will be Two surveys for each region were completed examined at different levels from a hierarchical annually by early August. These surveys are part perspective, including species presence and of a long-term study that was initiated in 1997 absences, abundance ranking, and absolute and continued through 2007. Sites were located abundance (Pimm, 1984; Lawton and Gaston, in the field using written directions, topographic 1989; Rahel, 1990). Groups of butterfly species maps, and GPS coordinates to find the site using similar functional guilds of plants will be marker stake within the meadow. In 1997, two examined for correlated changes. Changes in randomly selected cardinal directions (NW, NE, floral resource cover and host plant percent cover etc.) were used for the placement of a 50 m x 50 will also be monitored to relate to changes in m plot. This plot was annually measured and butterfly species abundance. flagged so that every year the same area was sampled. Surveys were conducted on sunny days when the temperature is above 70° F with + METHODS low to moderate wind. The survey lasted for twenty minutes with two people surveying Study Area butterflies within the plot. Abundance data were collected by netting butterflies, collecting them The Greater Yellowstone Ecosystem in glassine envelopes, and finally releasing them was divided into two study regions for our at the end of the survey after individual project, which will be referred to as the Gallatin butterflies were identified to the species level. and the Teton regions. The Gallatin region includes 30 sites within the Gallatin National At each of the 55 study sites, vegetation Forest and the northwestern portion of was surveyed once per season in the middle of Yellowstone National Park in Montana. The the growing season (July) in 20m x 20m plots Teton region has 25 sites within the Grand Teton which also had one comer of two cardinal National Park and Bridger Teton National Forest directions located at the site marker stake. Cover in Wyoming. The Gallatin and Teton regions are estimates to 1% resolution were made for ten separated by 192 km, yet both have similar plant most dominant forb species in each plot. Nectar and butterfly communities (Su et al. 2004). The resources were quantified by counting the meadows selected for the surveys in both regions number of racemes for all flowering plant are approximately at the same elevation with species along a 1 m wide transect positioned homogenous topographic features. The average diagonally across the 50m x 50m butterfly elevation for sites within the Gallatin region is survey plot and they were conducted on the same 2098 m, and 2120 m in the Teton region. The days as the butterfly surveys. To obtain climatic meadows range from 1 - 7861 ha, with an information we used two National Climate average meadow patch of 500 ha. Six meadow Weather Stations (240775: BigSky, and 486440: types with distinct plant species were Moran 5WNW) to represent the GYE study characterized, M1-M6, along a hydrologic regions. Daily precipitation and temperature gradient (hydric to xeric respectively) using data were obtained from these locations and satellite imagery (Jakubauskas et al. , 1996). The summarized at an annual level. To detect trends Gallatin region has five replicates of each in individual species over time, we will analyze meadow type from M1-M6, and the Teton region the butterfly species for responses in both has five replicates of each meadow type except abundance and distribution across the meadows characterized as M4, which are not hydrological gradient. Species with adequate represented in the Teton region. The meadows sample sizes will be analyzed individually by were characterized as suitable for survey sites if meadow type using regressions to test for they were within 8 km from a road or trail, a temporal trends and relationships with annual 2 Caruthers and Debinski: Montane Meadow Butterfly Species Distributions in the Greater Yel 87 climatic variables (e.g. , average daily elevation values for each site (Tables 1-2). We temperature, and precipitation) as well as host also include a report summarizing the overall plant cover, and nectar resources. abundance by species within each of the two study regions based upon data standardized to two surveys at each site per year across 5 years + R ESULTS between 1997-2007 (Tables 3-4). Future reports will summarize the butterfly community trends Here we provide an archive of some of relative to host plant, nectar, and environmental these long-term data, including maps of the study variables (temperature and precipitation). sites (Figs. 1-2) with UTM locations, area, and legend r'71 Yellows1cne IL...J National Park Meadow Types Ill M1 C3 M2 M M3 ... M5M .. M6 - ~.. "} ':/' : i "\ ~ ~ '" \ (' ~ .. ... " \. ~ _, ~ '- -... ~ !f~ · tl" .., , ... ,' ., .._ I I ..~ s,. 0 2 4 Miles .~ • ( l I I I I I \ I I ,.I I ~· ' Figure 1. Gallatin Study Region including 30 long-term montane meadow survey sites. Ml meadows are hydric, M3 mesic and M6 meadows are xeric. Published by Wyoming Scholars Repository, 2006 3 University of Wyoming National Park Service Research Center Annual Report, Vol. 30 [2006], Art. 14 88 # Trails Roads Te:ton Park Boundary (, Meadow Types ~ -1 "' • f> ;.." }t ' • M1 l" ~ "' . c:3 M2 }~1, i , ~ • M3 . ~ ~~ M5 • M6 ~ ..... 0 1.25 2.5 5 Miles I I I Figure 2. Teton Study Region including 25 long-term montane meadow survey