Continuous Hydrologic and Water Quality Monitoring of Vernal Ponds

Summary

Understanding the ecosystem services and processes provided by vernal ponds and the impacts of anthropogenic activities on their ability to provide these services requires intensive hydrologic monitoring. This sampling protocol using in-situ monitoring equipment was developed to understand the impact of anthropogenic activities on water levels and quality.

Abstract

Vernal ponds, also referred to as vernal pools, provide critical ecosystem services and habitat for a variety of threatened and endangered species. However, they are vulnerable parts of the landscapes that are often poorly understood and understudied. Land use and management practices, as well as climate change are thought to be a contribution to the global amphibian decline. However, more research is needed to understand the extent of these impacts. Here, we present methodology for characterizing a vernal pond's morphology and detail a monitoring station that can be used to collect water quantity and quality data over the duration of a vernal pond's hydroperiod. We provide methodology for how to conduct field surveys to characterize the morphology and develop stage-storage curves for a vernal pond. Additionally, we provide methodology for monitoring the water level, temperature, pH, oxidation-reduction potential, dissolved oxygen, and electrical conductivity of water in a vernal pond, as well as monitoring rainfall data. This information can be used to better quantify the ecosystem services that vernal ponds provide and the impacts of anthropogenic activities on their ability to provide these services.

Introduction

Vernal ponds are temporary, shallow wetlands that typically contain water from fall to spring and are often dry during the summer months. The inundation period of vernal ponds, generally referred to as the hydroperiod, is primarily controlled by precipitation and evapotranspiration¹.

Vernal ponds can also be referred to as vernal pools, ephemeral ponds, temporary ponds, seasonal ponds, and geographically isolated wetlands². In the northeastern United States, vernal ponds are most often characterized by the critical habitat they provide for amphibians, serving as the breeding grounds and provi....

Protocol

1. Conducting a Survey of a Vernal Pond Morphology

1. Select a location to designate as the benchmark and mark it with a small survey or marking flag.
   NOTE: The location should be a higher elevation than the pond and have line-of-sight from all locations across the pond.
2. Assign the benchmark a reference elevation; the exact number does not matter, it simply provides a reference to which all other elevations can be compared.
3. Using a tape measure and marking flags, make transects at a 3 m interval over the pond area, resulting in a 3 m x 3 m grid (see example in Figure 1).
4. Determi....

Results

Vernal ponds can exhibit a wide range of morphology, with profiles ranging from convex to straight slope to concave. Example morphology for a vernal pond in Central Pennsylvania is shown in Figure 1, along with the results of the stage-storage curve for this pond (Figure 2, Table 1). Maximum pond depth is not a strong indicator of surface area, as hydroperiod has only a weak correlation with pond morphology

Discussion

Significance with Respect to Existing Methods

While monitoring of streams has well-established methodologies developed by the United States Geological Survey (USGS), no such widespread monitoring program exists for understanding vernal pond dynamics. This protocol seeks to provide guidance for how to begin to approach hydrologic and water quality monitoring research at a vernal pond site, with the goal of understanding how physical and chemical factors may be changing over tim.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
CR1000	Campbell Scientific	16130-23	Measurement and Control Datalogger
ENC12/14-SC-MM	Campbell Scientific	30707-88	Weatherproof Enclosure Box (12" x 14")
CS451-L	Campbell Scientific	28790-82	Pressure Transducer
CM305-PS	Campbell Scientific	20570-3	47" Mounting Pole (Tripod)
TE525-L	Texas Electronics	7085-111	Tipping Bucket Rain Gauage (0.01 inch)
CS511-L	Campbell Scientific	26995-41	Dissolved Oxygen Sensor
SP10	Campbell Scientific	5278	10 W Solar Panel
PS150-SW	Campbell Scientific	29293-1	12 V Power Supply with Voltage Regulator & 7 Ah Rechargeable Battery
CSIM11-ORP	Wedgewood Analytical	22120-72	Oxidation-reduction potential probe
CSIM11-L	Wedgewood Analytical	22119-151	pH probe
CS547A-L	Campbell Scientific	16725-229	Water conductivity probe
A547	Campbell Scientific	12323	CS547(A) Conductivity Interface
CST/berger SAL 'N' Series Automatic Level Package	CST/berger	55-SLVP32D	Automatic Survey Level, Tripod, and 8' survey rod