United States 

 Department of 

 Agriculture 



Forest Service 



Northeastern Forest 

 Experiment Station 



Research Note 

 NE-327 



1985 



The Response of Plant Species 

 to Low-Level^f rampltlrf 'Stress 

 on Hurricane island, Maine 



i LL 



R. E. Leonard 

 P. W. Conkling 

 J. L. McMahon 



Abstract 



In 1981, a study was initiated to nneasure the effects of low-level trannpling 

 (100 to 200 tramples) on selected vegetation on Hurricane Island, Maine. Low 

 levels of trampling are representative of general recreational use patterns on 

 most Maine islands. The study was designed to compare percent survival of 

 common island species when subjected to low-level trampling, to observe 

 treadway formation, and to monitor recovery. The quadropod photographic 

 technique was used to monitor changes in area coverage of species. Climatic 

 conditions on Hurricane Island appear to favor rapid plant recovery. Most 

 species were able to withstand low levels of trampling stress if allowed a 

 recovery period of 1 year. The most resistant species were Picea rubens and 

 Cladina spp. The woody shrubs Empetrum nigrum, Myrica pensylvanica, and 

 Juniperus horizontalis and the tall herbaceous species Solidago rugosa and 

 Aralia nudicaulis were the least resistant to trampling stress. Recovery of 

 these species was relatively slow. 



Introduction 



Virtually no quantitative research 

 has been conducted on the effects 

 of human recreational use on Maine 

 island vegetation. Current policies 

 controlling human use on islands 

 owned by concerned individuals and 

 conservation organizations are based 

 primarily on visual assessment of 

 damage. Information on the short- 

 term and long-term effects of various 

 levels of use should be made available 

 to managers, so they can plan man- 

 agement policies actively rather than 

 contending with problems reactively. 



In 1979, a pilot investigation was 

 initiated on Hurricane Island, Maine, 

 to study the effects of high levels of 

 trampling (500 to 3000 tramples) on 

 trails located on a closed-canopy 

 spruce-fir site. A trample is defined 

 as a one-way pass by a single person 

 over the trail. Dense spruce-fir stands 

 are characteristic of many Maine 

 islands. Area coverages of ground- 



cover species are small, with light 

 being the major limiting factor. It was 

 found that high trampling levels pro- 

 duced little measurable trail forma- 

 tion, erosion, or soil compaction. This 

 was attributed to the thick resilient 

 layer of mor (an unconsolidated or- 

 ganic layer) and a zero percent slope. 

 However, the groundcover vegetation 

 that was monitored disappeared at 

 trampling levels lower than those the 

 pilot study was designed to analyze. 



The present study, begun in 1980, 

 was designed to quantify the effects 

 on individual groundcover species of 

 lower levels of human trampling (100 

 to 200 tramples) which are more rep- 

 resentative of general use patterns 

 on most Maine islands. Species re- 

 sponse to trampling and species 

 recovery were monitored on previously 

 undisturbed sites over a 3-year period. 

 Sites were selected to represent a 

 single dominant species or several 

 species in association. It has been 

 observed that the survival rate of a 



particular species may differ accord- 

 ing to whether it is growing in a pure 

 or mixed stand (Holmes and Dobson 

 1976). The major objectives of this 

 study were to measure and compare 

 the percent survival of common island 

 species subjected to low levels of 

 trampling, to observe treadway for- 

 mation, and to monitor plant recovery. 

 It was hypothesized that low-level 

 trampling would cause minimal dam- 

 age and that revegetation would 

 be rapid. A range of responses was 

 expected because of the different 

 morphological characteristics of the 

 species studied and site-specific 

 factors. 



Background 



Hurricane Island is 12 miles off 

 the mainland (latitude 44°02'N 

 longitude 69°53'30"W) southwest 

 of Vinalhaven Island at the mouth of 

 the Penobscot Bay. The granitic, 

 dome-shaped island is typical of many 

 Maine coastal islands in its geology, 

 history, climate, and vegetation. 



Hurricane Island is formed of 

 coarse-textured granite overlain by 

 glacial till and organic deposits. Soils 

 range from coarse gravelly sands 

 near the shore to thick layers of mor 

 beneath the forest canopy. Maine 

 island soils are generally young, 

 shallow-to-bedrock, acidic podsols 

 (Davis 1966). 



Many islands in the Gulf of Maine 

 were heavily used during the 18th and 

 19th centuries. At Hurricane Island, 

 the most intensive human use occurred 

 between 1870 and 1915, when the 

 island was home and workplace to 



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