Survey Methods

General Project Introduction
The goal of the WPT Habitat monitoring project was to identify and record potential Western Pond Turtle habitat on BLM lands in the Dorena, Marcola and Fall Creek areas. The sites we visited in the Eugene District have never been formally surveyed for the presence of turtles or their habitat, so turtle distribution and numbers are unknown .Our team successfully produced important baseline data on habitat quantity and quality that will help guide future restoration efforts by the BLM. Over the past ten weeks we have successfully surveyed 25 polygons.

 

BLM Training
Our team of 10 students were trained by the BLM in data collection methods and procedures. The first part of the training involved a presentation by Paula Larson on the biological requirements of the NWPT including behavior, breeding, distribution, and current management activities. Next we were given instruction on aerial photo interpretation, navigation, use of radios, and logistics of fieldwork and data collection. One of the most important parts of the training was on the use of Trimble GPS unit.

 

Tuesday Meetings
Each Tuesday the team meets to discuss how data collection went for the previous Friday and prepare for the upcoming Friday’s fieldwork. Our project leader Meghan assigns each of the three teams a new polygon to assess.  We then utilize BLM road maps and aerial photos to plan our route to the polygon.  We first use an aerial map marked with all of the polygons to locate a specific assigned polygon. We note it’s township, range, and section, then locate the location on the road map to determine our route.

 

Friday Field Work
Every Friday morning from week 2 to week 9, we meet on campus to assemble our equipment; which includes a Trimble GPS unit,  road maps and aerial photos, data collection sheets, a digital camera, compass, safety kit, and BLM radio. We double check our route, and each team travels to their assigned polygon.  Landmarks and road signs are used to identify when the team has reached their destination and where a polygon begins. Once the boundary of the polygon is determined, the team navigates toward the stream of interest.  In some places the streams run parallel to the road, providing easy access to aquatic habitat. In other areas we had to hike several hundred meters to reach the stream, often over steep terrain and dense vegetation.

Trimble
The GPS uses 24 navstar satellites which send signals to GPS receiver units. The Trimble GPS needs to be receiving a signal from at least 4 satellites at any one time to triangulate a UTM position. Every second, a UTM data point is recorded, and the GPS averages all of the UTM’s recorded for the one feature.  These UTM coordinates are used to locate and mark the feature on the aerial photo.  In many cases, topography or vegetative cover impaired the signal strength of the unit, resulting in fewer than four satellites. In this case, we use hard copy data sheets and manually mark the feature’s position on an aerial photo  estimate the location.  The GPS allowed us to create a digital record of each site surveyed and to associate a defined geographic location to the data.

In addition to the data recorded on the trimble GPS units, hard copy data sheets are utilized as a back source of information. We used standard data collection protocols. Much of the data collection process came down to judgment calls on whether aquatic and terrestrial habitats deserved to be recorded. The BLM provided us with general parameters of the features, such as dimensions and structures required. For aquatic habitat, the most important variable was existence of still water or slow moving pools. If this requirement was met, feature characteristics such as pool dimensions, presence of basking structure, and overhead canopy closure are recorded on both hard copy data sheets and into the Trimble unit.  Terrestrial habitat is identified by studying aerial photos for clearings in the forest canopy, and is confined to a maximum distance of 250 meters from the stream. Some of the parameters recorded are slope aspect, slope gradient, type of vegetation cover, and size. Many of these sites are labeled inaccessible due to extreme hill slopes or its location on the opposite side of the creek.