Introduction. Why Are They Important?

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1 Gradient habitat modeling of Regal fritillary and larval host plant using a distribution modeling approach with notes on life history attributes Kelsey McCullough, Gene Albanese & David A. Haukos Male Female

2 Introduction Why Are They Important? The Regal fritillary was once an abundant butterfly species of the prairie biome. Populations have declined approximately 99% in the prairie region and it is nearly extirpated from the eastern portion of its former range. However, populations within northeastern Kansas remain relatively abundant and are considered stable. Causes for the population decline of Regal fritillary remain largely undetermined but the decline of this species appears to be the result of habitat loss and the subsequent breakdown of metapopulation dynamics.

3 Regal Fritillary: Life History Larval development resumes in the spring with the emergence of young violet leaves, and is completed by late May - June. There are 6 larval instars. Regal fritillary eggs hatch in ~ 25 days. The 1st instar larvae immediately consume the chorion and enter diapause. Pupal stage of 2.5 to 4.0 weeks. Regal fritillary are univolitne with an adult flight from June- September. Females emerge 1-2 weeks after males. They mate soon after they emerge. Oviposition is delayed until late August- September. Females lay several hundred eggs with reports of some females laying more than 1,000 eggs. Oviposition behavior appears to be somewhat haphazard, with eggs laid singly near, but not necessarily on the violet host plants.

4 Larval Host Plant Background Prairie Violet Violets (Viola sp.) are the larval food plants for members of the genus Speyeria. While they are able to use a variety of species, Regal fritillary are associated with specific violet species in different parts of their range. Birdfoot and Prairie violet (V. pedata, pedatifida) are thought to be the preferred larval food plants throughout the Midwestand Great Plains. Prairie violet is a small perennial plant characteristic of native tallgrass communities within Kansas.

5 Objectives Provide spatially explicit estimates of the current distribution and relative abundance patterns of Prairie violet and identify habitat features and management practices that influence the occurrence and density of Prairie violet at the Fort Riley Military Reserve (FRMR) and Konza Prairie Biological Station (KPBS). Provide spatially explicit estimates of the current distribution and relative abundance patterns of adult Regal fritillary and identify habitat features and management practices that influence the occurrence and density of adult Regal fritillary within the FRMR and KPBS. Provide spatially explicit estimates of the current distribution and relative abundance patterns of post diapause female Regal fritillary and identify habitat features and management practices that influence the occurrence and density of post diapause female Regal fritillary within the FRMR and KPBS. Provide spatially explicit estimates of the current distribution and relative abundance patterns of Regal fritillary larvae and identify habitat features and management practices that influence the occurrence and density of late instar larvae among discrete clusters of Prairie violet within the FRMR and KPBS.

6 Predicting Prairie Violet Occurrence Methods We used Prairie violet occurrence data collected during the 2012 REU program at KPBS as the response variable in a maximum entropy model. Using GIS technologies we calculated a suite of surface metrics. From these surface metrics, we selected a parsimonious set of variables for the final distribution model.

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9 Field Validations of Prediction Areas Methods We randomly distributed ~ 312 violet survey points among the 4 study areas using GIS and then surveyed these points to validate the predictions of the species distribution model. 10m 2 plots were surveyed for ~12 min. After the entire plot had been searched the number of violets present were recorded. We also randomly selected a subset of points to re-survey to account for detection error. 27.5% of the plots surveyed had Prairie violets present.

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11 Larvae Surveys Methods During violet surveys we selected ~ 5 areas to conduct larvae surveys. After initial surveys at each point we used violet count data collected to predict the density of violets within grids using variogram and interpolation models. Based on model results, we searched for larvae within a subset of10m 2 and 5m 2 sub-plots inside each 100m 2 grid. We searched for larvae at various times including dusk, dawn, day and night. The 5 larvae that we detected were found during night surveys.

12 ,10 1, 9 1,8 1,7 1,6 1,5 1, 4 1, 3 1, 2 1,1 2,10 2, 9 2,8 2,7 2,6 2,5 2, 4 2, 3 2, 2 2,1 3,10 3, 9 3,8 3,7 3,6 3,5 3, 4 3, 3 3, 2 3,1 4,10 4, 9 4,8 4,7 4,6 4,5 4, 4 4, 3 4, 2 4,1 5,10 5, 9 5,8 5,7 5,6 5,5 5, 4 5, 3 5, 2 5,1 6,10 6, 9 6,8 6,7 6,6 6,5 6, 4 6, 3 6, 2 6,1 7,10 7, 9 7,8 7,7 7,6 7,5 7, 4 7, 3 7, 2 7,1 8,10 8, 9 8,8 8,7 8,6 8,5 8, 4 8, 3 8, 2 8,1 Prairie Violet Density High 9,10 10, 10 9, 9 9,8 9,7 9,6 9,5 9, 4 9, 3 9, 2 9,1 1 0, 9 10, 8 10, 7 10,6 10,5 10,4 10,3 1 0, 2 10, 1 Low

13 RODNEY Larvae Pupa Adult

14 Feed Sign

15 Adult Surveys Methods Adult surveys started in early June. Standardized transects were surveyed using a repeated, modified pollard walk method. Twenty six transects surveyed in Location of transects stratified by violet density and management regime i.e. grazing, fire return interval, haying etc. The coordinates and number of Regal fritillary detected within 4 distance classes to 30 meters from the transect and the initial coordinates of were recorded.

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17 Vegetation Surveys Methods Vegetation Survey Map We conducted vegetation surveys to characterize vegetation along transects and relate to adult abundance. Vegetation survey points were randomly distributed along adult survey transects. We used a modular vegetation plot method to quantify percent cover of trees, shrubs, grass, forbs, ferns, bare ground and litter. In addition to percent cover we also surveyed for host plants and measured vegetation height. We surveyed 182 vegetation plots along the 26 adult survey transects.

18 Oviposition Surveys Methods Oviposition surveys started in late August and were finished in early October. Standardized transects were surveyed using a repeated modified pollard walk method. 6 oviposition transects were surveyed in Location of transects stratified by violet density and management regime i.e. grazing, fire return interval, haying etc. Start/stop coordinates of followed females were recorded.

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20 Oviposition Surveys Results Oviposition Map We followed gravid females to record oviposition locations. Females were recorded depositing eggs at 27 locations. Each location was marked with a flag and habitat measurements were collected. 5 eggs were collected for further observations. Blue violet (Violoa sororia) was detected at 14 of the 27 locations.

21 Female Laying Eggs

22 Eggs & 1 st Instar Larvae

23 Prairie Violet Distribution Modeling Improving our SDM We used a similar analytical framework with the 2014 field data as we did with the pilot data to predict Prairie violet occurrence. To improve the current Prairie violet distribution model, we are using 2014 field data to model and compare alternative distribution modeling techniques that include: Random Forest (RF) Boosted Regression tree (BRT) Generalized Linear Model (GLM) Multivariate Adaptive Regression Splines (MARS). Better data (e.g., presence and absence data etc.) Comparing multiple models facilitates the selection of the model that best predicts the occurrence of Prairie violets (i.e., adaptive modeling).

24 Maps of Predicted Prairie Violet Occurrence within Study Areas in North Central Kansas

25 Preliminary Results Model Performance Top Covariates BRT correct classification rate 78.7% MARS correct classification rate 73.5% RF correct classification rate 68.4% GLM correct classification rate 60% Vegetation Index Roughness Annual Variation in Vegetation Index Heat Load Index

26 Conclusions Progress Using GIS and distribution modeling we produced a predictive distribution map of Prairie violet within our study areas. Our study identified environmental variables that predicted the occurrence of the Regal fritillary host plant, Prairie violet. Validated the species distribution model with field surveys. Collected larvae, adult, oviposition and supporting vegetation data. Implemented and improving the SDM s to compare and select among models.

27 Conclusions Coming Up We will validate the improved Prairie violet distribution model with new surveys within FRMR and KPBS. We will generate a species distribution model for Blue violet and test this model with field validations. We will collect a second field season of data on adults, larvae, ovipositioning females and collect supporting vegetation data among study sites. These data will then be applied to occupancy and distribution models as well as identify habitat and management attributes that are important to maintaining Regal fritillary populations.

28 QUESTIONS? ACKNOWLEDGMENTS: We gratefully acknowledge funding and support from the Department of Defense, Konza Prairie Biological Station, KSU Division of Biology, and the Kansas Cooperative Fish and Wildlife Research Unit.