Distribution of Impatiens glandulifera Royle along the river Irfon during June 2010

BIS for Powys & Brecon Beacons National Park

Description

A Global Positioning System survey and mapping of the distribution and relative abundance of <i>I. glandulifera</i> along the length of the river Irfon from its source to its outflow into the river Wye.

This dataset was completely prepared by Jon Paul Mccalmont. If you will have any qusetions or sugestions please contact him at: jonmccalmont@btinternet.com

Purpose

Survey carried out as part of a Bsc(Hons) dissertation study into genetic variation in populations of <i>I. glandulifera</i> along different river systems

Data quality

Survey carried out by a mature student studying for a BSc(Hons) in countryside management at Aberystwyth University.

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Records of incidence are recorded accurately using GPS; care was taken to establish the first incidence of <i>I. glandulifera</i> along the river with a view to the usefulness of this information in any future control efforts.

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Some data attribute assessments have a subjective nature but survey carried out by one individual so consistency should be maintained to a reasonable level.

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Water levels remained low (no rain) during entire survey so consistency of integrity to river's edge has been maintained wherever possible.

Track logs of actual survey pathways are available in accompanying KML file.

Methods

Primary method of data capture was to walk the length of the river keeping as close as possible to the river's edge (water levels were extremely low which enabled a high level of integrity to the edge), including examination beneath overhangs where sporadic populations are likely to be found. Survey was carried out prior to plants coming into flower; plants were identified by their very distinctive vegetative form. A track log of the survey path, population sites of plants and the extent of these were recorded using Garmin Etrex Summit HC GPS and significant populations (<i>see criteria below</i>) were entered onto data sheets at site with attributes and comments.

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Results were downloaded from GPS to KML file daily and the results; (<i>sighting recordings and survey track logs</i>) are presented using Google Earth (<i>see accompanying KML file</i>) including attribute information and collated as an NBN Data Exchange format table. Record locations are accurate to within 10m.

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<b>Scoring Criteria</b>

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<u>Population</u>

Sporadic area <2m x 2m AND <50 individuals

Significant area >2m x 2m OR >50 individuals

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<u>Area</u>

Area measurements of populations are only approximate due to often indeterminate boundaries; larger areas are GPS marked and subsequently measured using Google Earth. Length of population along the river's edge is indicated by the first number in the area score, the second indicates width. Record key locations will indicate the eastern edge of the population.

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<u>Abundance</u>

Assessed subjectively using the scale <50/>50/>100/>1000

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<u>Density</u>

Subjective due to logistics but density scoring scale was established as follows

<i><b>1</b> = Very scattered, <1 per. 0.5 m2 (Large amounts of bare ground or other plants)

<b>2</b> = Scattered, <10 per. 0.5 m2 (Minority mix with other plants or predominantly bare ground)

<b>3</b> = Dense, <20 per. 0.5 m2 (Majority mix with other species, no bare ground)

<b>4</b> = Very dense >20 per. 0.5 m2 (Exclusively I. glandulifera with no bare ground)

Density scores are given as an average over the area of population though may be higher locally within it which may be indicated in comments.</i>

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<u>Site Key</u>

Initial letter (A, B, C, D, E) corresponds to location and date (<i>see geographical coverage below</i>). Second letter indicates bank N = North bank, S = South bank.

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<u>Record Key</u>

N = North bank, S = South bank

Record numbering runs sequentially east to west (<i>in any disjunction in sequence (e.g. N78, N79, N80, N82) the missing key (N81) will have been used in the KML file to indicate the end point of a large population</i>).

Citation

No citation information available.

Rights

CC-BY-NC

Digitised records