Post on 16-Aug-2020
The effect of man-made dams on peripheral stream-dwelling populations of
Nigronia serricornis (Say) (Megaloptera: Corydalidae).
We would like to thank the NYDEC bioassessment
unit for site information and EE Castle, CL Picucci, MJ
Dami, JS Salvino, LA Salvino, and EH Salvino for
assistance in the field. This research is funded by grants
from the SUNY College Senate Committee on Research.
Joanna R. Salvino Faculty Sponsor: Jeffrey S. Heilveil, Ph.D.
Biology Department, SUNY College at Oneonta, Oneonta, NY
Fine-scale interactions within a species promote
broad-scale population health by allowing for adaptation
in changing environments. The geography of a region
dictates the movement and interaction of natural
populations; for example, physical features can impede
dispersal.
Altered landscapes as a result of anthropogenic
development may also inhibit physical interactions
among organisms. Yammamoto et al. (2004) showed that
man-made reservoirs directly affect gene flow patterns
upstream and downstream of the dam, but there has not
been much, if any, research on the effect of reservoirs on
peripheral populations.
The dam that was built in the 1950s to create the
Pepacton reservoir in Delaware County, New York flooded
out four villages and turned a free-flowing river into a
relatively still-water area. This type of man-made land
alteration could potentially affect stream dwellers such as
Nigronia serricornis, the saw-combed fishfly (Figure 1).
Data collected by the NYSDEC show that Nigronia
serricornis lives in many streams surrounding the
Pepacton reservoir, and would be a model organism to
sample for this project.
Bioassessment data from the NYS DEC was used to find
2 sets (one plot in tributaries that feed directly into the
Pepacton Reservoir, and one plot in tributaries indirectly
connected to the Pepacton Reservoir by the Delaware River,
that will serve as a reference) of 3 sites at roughly the same
geographic distance (<12 km) (Figures 2 &3). Up to 20 N.
serricornis larvae per site were collected on ice and returned
to SUNY College at Oneonta for DNA extraction. Larvae will
be genotyped for two polymorphic microsatellite loci
developed recently by Stevenson (2013), and will be
amplified using the thermal cycler protocol of Real et al.
(2009). Tests of Hardy-Weinberg Equilibrium, Analysis of
Molecular Variance (AMOVA; used to calculate FST, a measure
of genetic isolation), pairwise-calculations of FST, and exact
tests of sample differentiation will be performed using
Arlequin (Excoffier 2005)(ver. 3.5.1.3). These tests will be
used to compare the amount of genetic isolation between the
sites both on and off the reservoir, and help to determine the
role of the reservoir as a barrier to gene flow.
ABSTRACT
INTRODUCTION
METHODS
LITERATURE CITED Excoffier, L., Guillaume, L. and S. Schneider. 2005. Arlequin (version 3.0): An integrated software package for
population genetics data analysis. Evolutionary Bioinformatics Online 1: 47-50.
Real, K. M., D. J. Schmidt, and J. M. Hughes. 2009. Mogurnda adspersa microsatellite markers: multiplexing and multi-tailed primer tagging. Conservation Genetics Resources 1:411-414.
Stevenson, R. M. 2013. Facilitating Ecological Research: Development of microsatellite markers for the megalopteran Nigronia serricornis (Say). M. Sc. Thesis. State University of New York, College at Oneonta.
Yammamoto S, Yurita K, Koizumi I, Maekawa K (2004) Genetic differentiation of white-spotted charr (Salvelinus
leucomaenis) populations after habitat fragmentation: Spatial-temporal changes in gene frequencies. Conservation Genetics. 5: 529 - 538.
Fig. 1: Nigronia serricornis (Say)
ACKNOWLEDGEMENTS
SIGNIFICANCE OF RESEARCH
I will use molecular data to determine whether the Pepacton reservoir in Delaware County, NY has an impact on the genetic exchange, or
gene flow, between populations of Nigronia serricornis (Say). Individuals were collected from six sites surrounding the Pepacton reservoir: three
in tributaries directly connected to the reservoir and three in tributaries indirectly connected to the reservoir by the Delaware River. Recently-
developed microsatellite markers, genetic markers commonly used in forensics and population genetics, will be used to genotype collected
individuals, determine their relatedness, and compare the level of gene flow between metapopulations on and off the reservoir.
By answering these questions, we can gain a better
understanding of the contemporary effects on aquatic
organisms in our area. These data should allow for the
contribution of growing literature on anthropogenic
impacts on natural populations and hopefully inform
stakeholders and planners about any indirect impacts of
impoundments on gene flow. Furthermore, these data
can also be used in planning mitigation projects, aiding
conservation projects in flowing water ecosystems.
Fig. 3: Map of specific sites. Inset shows location of reservoir in NYS.
Fig. 2: Pepacton Reservoir, Delaware County, NY.
© A. Hornburg Heilveil