Investigating Native versus Exotic Species with Regard to Biodiversity

NH Conservation Moose Grant

Souhegan High School

RESULTS

Introduction –  Results /Data Analysis

Using the Smithsonian Institution's Monitoring & Assessment of Biodiversity (SI/MAB) permanent biodiversity research protocols, Souhegan High School students have begun collecting biological research data at a field site located in Amherst, New Hampshire. The site was established as “Experimental Biodiversity Plot - March, 2004”.

The overall goals of this HabitatNet project are to (1) develop conservation biological literacy in high school students by giving them an opportunity to learn field methods and applications while collecting and interpreting biological diversity data and (2) establish baseline biological diversity data for HabitatNet / SIMAB field sites.

Annual field reports will be written and submitted to the Smithsonian Institution and interested NH conservation organizations. Field reports will include twenty (20) meter by twenty (20) meter forest quadrant tree maps, vegetation analysis (tree species frequency, dominance values, and density statistics), invertebrate and vertebrate species lists. Additionally, concurrent student research projects that compliment the basic biodiversity data that will be collected using the SI/MAB protocols. The concurrent projects are designed by the students to conduct in the field and focus on an aspect of anthropogenic or "natural" disturbance regimes as they pertain to biological diversity.

Section 1 – Methods

During the Spring, 2004 semester, four (4) quadrants were surveyed in the Experimental Biodiversity Plot (“EX04”). The focus of this field project was to establish a SIMAB Biodiversity Plot that will examine biodiversity indices with regard to native versus exotic plant species recruitment.

· Plot Selection and Establishment

Selection of the plot site was crucial for both the educational and research values. Thus, the site selection was based on the following criteria:

· The area contained species representative of both native and exotic / introduced species for this region.

· Common or dominant species were represented.

· The plot was located within one geographic area to give a true representation of the area's diversity differences.

· The plot had access for future school groups.

The forest plot was established according to Dallmeier / SIMAB(1992). At most new sites, professional survey or topography teams delineate a one hectare plot (100 X 100 meters) and divide it into 25 quadrants, each 20 x 20 meters in size. Thus far, four (4) quadrants have been surveyed.

· Field Measurements

Tree tagging and identification began after the corner stakes of the quadrants were set. The process included locating, measuring, marking, and mapping all trees with a diameter at breast height (DBH) of 10 cm in the “Native” quadrants and 4 cm in the “Exotic” quadrants. Diameter tape was used to measure DBH, avoiding any protrusions on the trunk. Where multiple stems occurred on a tree, all individual stem diameters of 1 cm were measured. Trees were tagged with an aluminum label facing toward the base line of the plot and set with a nail 1.3 M above the ground. The nails thus serve as a general guide for future measurements.

Trees were tagged with an individual number consisting of a sequence of two digits. Using (20-24) as an example, the first pair of numbers (20) identified the quadrant within the plot in which the tree was located, while the second pair (24) identified an individual tree within the quadrant. No other tree received that number. In each quadrant the tree numbers started at one and continued until the last tree was labeled.

Section 2: Comments

As previously mentioned, plant community data for site EX04 is currently being compiled (see RESULTS). On-going work at that site will continue to include surveys of invertebrates and vertebrates located at that site and a re-census of the tree species (DBH) measured in the initial census. Data on tree growth will compliment the overall plant community data collected in future years.

Currently, this preliminary data indicates that the Exotic quadrants have very high Dominance values for an exotic species (Russian Olive) with correspondingly low species richness values. Within the Native quadrants, diversity values are decreasing (Table 1) given the late seral stage of this secondary growth forest. The Native quadrats are approaching a “climax” plant community composed of oak and hickory tree species.

 Table 1.

“If the land mechanism as a whole is good, then every part of it is good, whether we understand it or not. If the biota, in the course of eons, has built something we like but do not understand, then who but a fool would discard seemingly useless parts? To keep every cog and wheel is the forest precaution of intelligent tinkering”

 A SAND COUNTY ALMANAC – Aldo Leopold