A PROCEDURE FOR IDENTIFYING INVASIVE WILD PARSNIP PLANTS BASED ON VISIBLE BANDS FROM UAV IMAGES

Wild parsnip is an invasive plant that has serious health risks to humans due to the toxin in its sap. Monitoring its presence has been a challenging task for conservation authorities due to its small size and irregular shape. Unmanned Aerial Vehicles (UAV) can obtain ultra-high resolution (UHR) imagery and have been used for vegetation monitoring in recent years. In this study, UAV images captured at Lemoine Point Conservation Area in Kingston, Ontario, are used to test a methodology for distinguishing wild parsnip. The objective of this study is to develop an efficient invasive wild parsnip classification workflow based on UHR digital UAV imagery. Image pre-processing flow includes image orientation, digital elevation model (DEM) and digital surface model (DSM) extractions, and orthomosaicking using Simactive’s software. Three vegetation indices and three texture features are calculated and added to the mosaicked images as additional bands. Image analysis frameworks namely pixel- and object-based method and three classifiers are tested and the object-based Support Vector Machine (SVM) is selected to distinguish wild parsnip from other vegetation types. The optimal image resolutions are undertaken by comparing accuracy assessments. The results provide an executable workflow to distinguish wild parsnip and show that UAV images, with a simple digital camera, are an appropriate and economic resource for small and irregular vegetation detection. This method yields reliable and valid outcomes in detecting wild parsnip plants and demonstrates excellent performance in mapping small vegetation.

Patterns of Genetic Diversity in the Globally Invasive Species Wild Parsnip (Pastinaca sativa)

Wild parsnip is an invasive species with a global distribution in temperate climates. Parsnips are native to Eurasia and have been cultivated for more than five centuries. It is unclear whether the global invasion of this species is a consequence of escape from cultivation or the accidental introduction of a Eurasian wild subspecies. In this study, we used nuclear ribosomal DNA internal transcribed spacer (ITS) and chloroplast DNA (cpDNA) markers to evaluate the genetic structure of wild parsnip in its native range (Europe) and in three distinct geographic regions where it is considered invasive: eastern North America, western North America, and New Zealand. We also compared wild and cultivated parsnips to determine whether they are genetically distinct. From 112 individuals, we recovered 14 ITS and 27 cpDNA haplotypes. One ITS haplotype was widespread; few haplotypes were rare singletons. In contrast, at least two lineages of cpDNA haplotypes were recovered, with several novel haplotypes restricted to Europe. Cultivated parsnips were not genetically distinct from wild parsnips, and numerous wild parsnip populations shared haplotypes with cultivars. High genetic diversity was recovered in all three regions, suggesting multiple introductions.

The Biology of Canadian weeds. 144. Pastinaca sativa L.

The parsnip, Pastinaca sativa, was introduced to North America shortly after European settlement as an important root-crop. It subsequently escaped cultivation and naturalized as a less palatable “wild” form. Cultivation of parsnip has diminished in Canada to the point where it is now only a minor crop, but the wild form has increased as a troublesome weed, particularly in eastern regions. Wild parsnip is most prevalent in eastern Canada and the northeastern United States, but occurs across the continent except in the far north and extreme southeast. As a monocarpic biennial with a large tap root, it reproduces entirely by seed. A wide variety of habitats and soil types are tolerated. It is considered a noxious weed because of its toxic properties (primarily photo-activated dermatitis) to both humans and livestock. It invades disturbed sites, rights-of-way, pastures, perennial crops, and reduced-tillage fields where it effectively out-competes shorter vegetation. In arable fields, wild parsnip is normally controlled by tillage. Manual removal, cutting, and mowing can be effective in reducing seed production, but direct contact with plants or sap is hazardous. Various herbicides have been reported to be useful in the control of wild parsnip (e.g., glyphosate, 2,4-D, triclopyr, etc.), but little quantitative information is available on application rates and levels of control.Key words: Panais sauvage, Pastinaca sativa, PAVSA, weed biology, wild parsnip

Browsing for conservation: Springtime forage value of midstory shrubs of degraded oak savannas in southern Wisconsin

Oak (Quercusspp.) savanna is a rare and dwindling ecosystem primarily due to the clearing of vast areas for agriculture and encroachment of woody midstory shrubs in the remnant areas. There is interest in introducing controlled grazing to re-open these ecologically sensitive semi-wooded areas. We report the forage quality and diet selection by Scottish Highland cattle (Bos taurusspp.), a breed recognized for their browsing behavior, of the most common shrubs in this ecosystem. Shrub species sampled included prickly ash (Xanthoxylem americanaMill), gooseberry (Ribes missourienseNutt.), gray dogwood (Cornus racemesaL.), multiflora rose (Rosa multifloraThunb. ex Murr.), black or red raspberry (Rubusspp.) and wild parsnip (Pastinaca sativaL). Leaf biomass was collected in June 2001 and 2002 and analyzed for forage quality. Animal observations showed that diet included a fairly even mixture of shrub leaves, grass and herbaceous forbs. Prickly ash and raspberry were most frequently browsed and had the highest crude protein (CP; 190 g kg−1), while multiflora rose and gray dogwood, neither highly browsed upon, had the lowest levels of CP (120 g kg−1). All shrubs had highin-vitrotrue digestibility, with prickly ash approaching 850 g kg−1(as compared to 688 g kg−1for mature alfalfa). The quality of the shrub layer in late spring is adequate to provide nutritional support for beef cattle as long as dry matter intake is not limited. Integrating shrubs into the rotation could expand the pasture base by providing feed at a time when cool-season pastures are typically quasi-dormant.