Table of Contents Executive Summary 2



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Table of Contents

Executive Summary 2

Introduction 3

Problem Statement 3

Stakeholders 3

Goals 4

Site Description 5



Methods 7

Research 8

Habitat Destruction, Alteration, and Fragmentation 8

Amphibian Movement Patterns and the Effects of Roads 10

Global Amphibian Decline 19

Anthropogenic Causes of Amphibian Population Decline 20

Consequences of Amphibian Loss 24

Amphibians and Culverts 25

Culvert Replacement/Upgrade Costs 27

Case Studies: Management Strategies 29

Site Assessment Metric 32

Alternatives Table 33

Alternatives Analysis and Discussion 35

Recommendations 38

Current Actions 38

Further Research Needs 41

References 46

Executive Summary


Purpose of project

Talk about agency

Talk about why grand isle and franklin

Talk about evolution

Need for future information

This is designed to get the ball rolling until funding and knowledge catch up…


Introduction

Problem Statement


Numerous species of amphibians found in Vermont wetlands have wide-ranging habitat requirements, leading to movement around and between wetlands and into upland habitats. This behavior coupled with the presence of roads through and near wetlands has led to high levels of amphibian mortality due to vehicle encounters. No safe passage currently exists for these delicate organisms to safely cross roads. Current actions in Vermont are sparse and mainly consist of using fencing to prevent access to roadways. This action is effective at reducing vehicle encounters but it will not work at any sites with species that need to access habitat on the other side of the road. Existing infrastructure contains thousands of road crossings such as culverts and bridges that are currently not heavily used by amphibians while crossing roads. A management plan is needed to utilize existing infrastructure to allow amphibians to safely cross the road while remaining economically feasible. In order to maximize the benefits of this plan a detailed site assessment metric is necessary.

Stakeholders


  • Vermont Agency of Natural Resources (VTRANS): The reason that amphibian road crossings may indeed become a reality in Vermont is due to the commitment of the staff of the Vermont Agency of Transportation (VTrans) Environmental Section. Currently, they are involved in several projects, such as a kestrel nest box program, a “frog fence” to prevent frog mortality on a busy state highway, mapping vegetation communities along I-89 in an attempt to reconfigure mowing schedules to least impact wildlife, as well as researching methods to implement more wildlife crossings on state highways and to reduce impacts of storm water discharges on water quality. It is their goal to make VTrans a proactive, environmentally conscious transportation agency that will become a model for other state transportation agencies.

  • Biologists and ecologists: This problem is of special concern to scientists due to the numerous factors leading to widespread amphibian decline. These species are already very stressed by habitat loss, pollution, UV radiation, and numerous other challenges. Reptiles and amphibians are an important link in wetland food webs.

  • Recreational people and sightseers: Many people relate the gentle chirping of spring peepers or the rough calls of bullfrogs to the feeling of being with nature. Catching frogs is a favorite activity for small children and some adults. Cyclists have complained about high numbers of frog road kill in the past as both disgusting and a potential safety hazard.

  • Motorists: Hopefully few people feel good about running over snakes, turtles, or frogs. There is also a potential for accidents to occur while swerving to avoid these animals.

  • The general public: The general public is the most important stakeholder due to the potential need of taxpayer funding for any construction projects related to addressing this problem. The general public may have cause for concern over mosquitoes and mosquito-borne diseases such as West-Nile due to the heavy feeding of amphibians on larval and adult mosquitoes.

  • Political Representatives: Political representatives have a measurable impact on potential changes to be made. County representatives would be an integral part of any construction activities, site assessment, and funding arrangements.

  • Volunteers: A Boy Scout troop or other civilian group could be a useful way to maintain silt fences or other impermanent structures. Civilian groups from other parts of the country have formed bucket brigades to move amphibians across the road.

Goals


  • Research causes and effects of amphibian decline on global and local scales to emphasize the importance of reducing mortality sources when feasible/possible

  • Develop a metric for assessing and prioritizing sites for their suitability and need for road crossing modifications

  • Determine “why the frog crossed the road”: Conduct research to determine why amphibians and reptiles move and come in contact with roadways

  • Create a detailed list of short-term management actions for low-cost high-return road crossing alternatives

  • Create a detailed list of long-term management actions for permanent road crossing structures

  • Present recommendations for VTRANS to address vehicular mortality in amphibian populations using crossing structures along Vermont-state roads


Site Description


Vermont is located in the northwest corner of New England and is bordered by Lake Champlain and New York state to the west; Quebec, Canada to the north; New Hampshire to the east; and Massachusetts to the south. It is oriented primarily along a north-south axis. Latitude is between 42º and 45º north, and longitude is between 70º and 73º west (Perkins Museum of Geology website). Total land area is approximately 9,250 square miles (U.S. Census Bureau website).

Vermont topography varies throughout the state, which has led to the state being divided into six physiographic regions: the Green Mountains, the Taconic Mountains, the Valley of Vermont, the Champlain Lowlands, the Vermont Piedmont, and the Northeast Highlands. The Green Mountains run the entire north-south length of Vermont, down approximately the middle of the state, and contain the highest peaks in Vermont. The Taconic Mountains are located in southwest Vermont and are lower, rounder, and older than the Green Mountains. The Valley of Vermont is a flat, narrow strip of land that runs between the Green Mountains to the west and the Taconic Mountains to the east. It is essentially an extension of the Champlain Lowlands, which is the area including Lake Champlain and its surrounding, fertile, relatively flat basin. The Champlain lowlands are bordered to the west by the Green Mountains, to the east by the Adirondack Mountains, and to the south by the Taconic Mountains. Due to the moderating effects of Lake Champlain and the protection offered by the mountain ranges on three sides, this area experiences the mildest climate in the state. The Vermont Piedmont runs the north-south length of the state to the east of the Green Mountains, comprising the foothills of the Green Mountains and characterized by rolling hills, wide valleys, and many lakes. Finally, the Northeast Highlands are located in the northeast corner of Vermont and are actually an extension of the White Mountains of New Hampshire, making them quite different from any other region in Vermont. Here, the climate is second in severity to only the highest peaks of the Green Mountains (Johnson 1998).

Generally, the climate of Vermont is considered humid continental-cool summer, which is characterized by average temperature of the coldest month (January) < 32º F and average temperature of the warmest month < 72º F. In Vermont, the temperature is influenced more by altitude in the summer, by latitude in the winter, and varies with topography statewide. The average length of the growing season also differs depending on topography, from approximately 90 days at higher elevations and in small, low valleys to 150 days near Lake Champlain. Lake Champlain has a considerable buffering effect on the climate of the Champlain Valley (Meeks 1986).

Precipitation patterns mirror those of temperature, again varying with topography. Average annual precipitation ranges from approximately 32” to 52”. In general, higher elevations (Green Mountains) receive more precipitation, as do the southern part of the state and the Northeast Highlands. Vermont is also one of the cloudiest places in North America; the amount of solar energy that falls on Vermont is nearly the smallest amount in the United States (Meeks 1986).

Dominant vegetation can be approximated into four primary zones. Northern hardwoods (birch, beech, and maple) dominate below 2,000 feet, except in Northeast Vermont. The central Champlain Valley is characterized by oak-hickory forest. Above 2,000 feet and in the Northeast Highlands, the primary vegetation communities consist of spruce-fir. Finally, on the few peaks close to 4,000 feet, there are scattered spots of alpine vegetation. In many of the lower elevations, such as in Franklin and Addison Counties, dairy farms still comprise a large portion of the landscape, so these areas may be less forested than other locations in the state (Meeks 1986).

Vermont remains one of the most rural states in the nation, with an estimated 2001 population estimate of 613,090 people. In 2000, the average number of persons per square mile was 65.8. Population is most dense in the Greater Burlington/Chittenden County area, and also in the Rutland, Brattleboro, and Montpelier areas (U.S. Census Bureau website). The 9, 250 square mile land area is traversed by a total of approximately 15,009 miles of roads (14,305 miles of state public roads and 704 miles of the National Highway System). In 2002, the grand total of urban and rural annual vehicle miles of travel was 9,573.8 (VTrans website). Although it is difficult to summarize traffic statistics, for there is too much variance between different roadways, a generalization that may be made is that traffic decreases in intensity from Interstate highways; down through Class I, II, III, and IV state highways; to town highways. However, this is only a generalization, for town roads in more urbanized locations may experience greater traffic intensity than state highways in more rural locations.



Historical Context

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