Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
208 MUELLER LABORATORY
UNIVERSITY PARK,PA 16802
Performing Department
Entomology
Non Technical Summary
Current forest management practices generate little area in early successional stages, but these open habitats are critical for supporting wildlife, biodiversity and forest productivity. Periodic wildfires, large grazing animals, and other disturbances maintained the post-glacial landscape of the eastern deciduous forest at a variety of successional stages. However, many of the native species that inhabit early successional stages began experiencing declines with anthropogenic disturbances such as fire suppression that allowed the conversion of open habitats into closed-canopy forests. In addition, the relative abundance of a keystone herbivore, the white-tailed deer, is currently several times greater than historic levels. Such novel changes have contributed to the altered natural areas that we have today.Savannas, where only scattered trees grow amongst herbaceous vegetation, are one of the most highly threatened habitats in the eastern temperate zone of North America. The sundial or blue lupine (Lupinus perennis) is often an indicator of high-quality savannas. In addition to being a species of conservation concern itself, lupine's decline has been linked to the decline of several insects of conservation concern that feed on it. Understanding the management needs and levels of genetic diversity of lupine is of critical importance for the conservation of this species, the pollinators that service this plant, the insects that depend on lupine, and North American savanna communities in general. Our research will support components of the missions of Pennsylvania's Bureau of Forestry "to ensure the long-term health... of the commonwealth's forest and to conserve native wild plants" as well as the Game Commission "to manage and protect wildlife and their habitats." Our objectives are to:(1) assess the effects of prescribed fire for conserving and/or enhancing lupine populations, habitat and associated insects,(2) determine how reduced white-tailed deer abundance affects L. perennis populations, habitat and pollinator communities, and(3) quantify the genetic diversity of Pennsylvania's large and small lupine populations and characterize the degree of genetic differentiation among them.
Animal Health Component
20%
Research Effort Categories
Basic
80%
Applied
20%
Developmental
(N/A)
Goals / Objectives
We propose to investigate the roles of fire management, deer pressure and plant genetic diversity on the health of lupine populations and its pollinators in Pennsylvania. Our specific objectives include: (1) assess the effect of prescribed fire on lupine population vigor, habitat and associated insect pollinators, (2) determine how reduced white-tailed deer abundance affects lupine population vigor, habitat and pollinator communities, and (3) quantify the genetic diversity of Pennsylvania's large and small lupine populations and characterize the degree of genetic differentiation among them. Our long-term goals are to seek additional funding to (1) examine long-term effects of reduced deer pressure and regular fire intervals on lupine population maintenance, and (2) to determine the minimum viable population size and the costs/benefits to outcrossing populations.
Project Methods
At 5-10 sites, we will set up a full factorial experiment to test the effects of prescribed fire, deer exclusion,and their interactions. We will assess plants, pollinators and the abiotic environment before and after treatments (details below).Objective 1: Assess the effects of prescribed fire (or proxy management activities where fire is not feasible) for conserving and/or restoring lupine populations, habitat and associated insects.Sampling: To test fire effects, we will delineate the boundaries of 5-10 of the larger lupine populations across Pennsylvania. Due to variation in population abundance and area, our methods will vary to accommodate site differences. For example, each site will include all of the delineated lupine area plus an additional 50-100% sized no-lupine zone that encompasses it. We will randomly select half of each site for dormant season fires (or proxy treatments, e.g., logging, mowing, raking, blow torching, etc., if burning is not feasible) to be conducted by certified professionals working for Pennsylvania's Bureau of Forestry and Game Commission. We will conduct a wide variety of environmental, vegetation, lupine and insect observations pre- and post-treatment. For example, at the site level, we will measure trees and note any post-treatment mortality. We will take soil samples for texture and pre- and post- chemistry analyses. We will set up 8-40 1 m2 quadrats along transects per site (Figure 2) where we will conduct a detailed suite of observations during spring and summer visits on: lupine demographics, abundance of forb flowers, pollinator visitation, percent cover of plants by height classes and ground layer features, light availability, and leaf litter thickness.During summer 2022, we will collect lupine seeds from each site. The seeds will be stratified (Mackay et al. 1996), and some may be germinated at Mt. Cuba through an existing arrangement with Pennsylvania Bureau of Forestry, before being planted back into their original sites in spring 2023 inside and outside of the extant lupine populations in treated and control plots. Seeds/seedlings will be marked and survival assessed during summer 2023 visits.Analysis: We will use multiple regression to test for relationships between lupine and the other habitat variables. With non-metric multidimensional scaling (NMDS), we will look for patterns between the environment, the fire treatment and the vegetation and insect communities. We will use analysis of variance (ANOVA) to test for change of our response variables with treatment. These analyses will require a couple of months to be completed with collaborators meeting weekly in-person or over Zoom.Objective 2: Determine how reduced white-tailed deer abundance affects Lupinus perennis populations, habitat and pollinator communitiesSampling: Land managers and/or researchers will fence half of the previously described fire/control treatment areas to exclude deer after the burn is completed (Figure 2). Before and after treatment, while conducting the observations described under Objective 1, we will also note the number of recently browsed stems of herbaceous and woody plants by species in quadrats. Plant size, abundance of flowers and abundance of pollinators are germane to our investigation of deer effects as well as fire effects. The seed/seedling planting locations described for Objective 1 will span exclusion treatments as well as fire treatments.Analysis: Similar to and in tandem with Objective 1 analyses, we will use NMDS and ANOVA to evaluate change of our response variables with treatment.Objective 3: Quantify the genetic diversity of Pennsylvania's large and small lupine populations and characterize the degree of genetic differentiation among them.Sampling: We will collect 30 individuals from the large populations studied for Objectives 1 and 2. In addition, we will characterize the genetic diversity of 5 small populations in Pennsylvania, and five populations from other states. Sample collection methods will not kill the plants as only one leaf is necessary.Analysis: The genetic analysis comprises multiple steps that include testing of previously published microsatellite primers, the de novo development of species-specific microsatellite markers, the optimization of these primers for PCR multiplex, their genotyping and the analysis for the detection of individuals of hybrid ancestry. We will extract genomic DNA from two lupine individuals and use it to develop enriched libraries for microsatellite discovery (López-Uribe et al. 2013). We will aim to identify at least 15 microsatellite markers that have clean genotypes (are easy to score) and that show variability across individuals. We will test and potentially include the microsatellite markers previously published for lupine (Gibbs et al. 2012). Once we have identified the final set of microsatellite markers, we will develop a protocol to multiplex these loci into two reactions. These multiplex reactions will be optimized combining microsatellite fragments that differ in their product length and different fluorescently labeled primers. We will quantify levels of genetic diversity using expected heterozygosity (He) and allele richness (Ar), and patterns of genetic differentiation using discriminant analysis of principal components (DAPC) and a STRUCTURE analysis.