University of GothenburgUniversity of Alberta The effects of edges and trampling intensity on vegetation in urban forests east of Edmonton, Alberta, Canada An honours thesis in Environmental Science University of Gothenburg, Göteborg, Sweden Environmental Sciences Program University of Alberta, Edmonton, Canada Department of Renewable Resources Weronica Isaksson March 19, 2004

University of GothenburgUniversity of Alberta Outline of this presentation  Background  Objectives of the study  Study Area and Design  Stated hypothesis  Results  Summary  Conclusions

University of GothenburgUniversity of AlbertaBackground  Part of the Project for Edge and Trampling Effects (Project ET). (Project ET).  Study 1: Performed in Finland by University of Helsinki. Started in Helsinki. Started in  Study 2: Performed in 3 urban forests east of Edmonton by the Department of Renewable Resources Edmonton by the Department of Renewable Resources at the University of Alberta. Started summer at the University of Alberta. Started summer  Additional studies will probably be performed in other countries (and cities). countries (and cities).

University of GothenburgUniversity of Alberta Background (cont.)  Project ET consists of 2 sub-projects with focus on 1. Carabid fauna (Dr. Matti Koivula) 2. Vegetation  My honours thesis Sub-project 2 with focus on vegetation. Sub-project 2 with focus on vegetation. Data collected once in summer 2003.

University of GothenburgUniversity of Alberta Objectives of this study  Influence on vegetation structure, composition and diversity by: composition and diversity by:  forest clearing  human access for recreational use.  Examine effects on forest structure, composition and diversity for: composition and diversity for:  distance from edge of trailheads towards interior forest  trampling on paths

University of GothenburgUniversity of AlbertaDefinitions  Edge  Boundary between ecosystems with different vegetative composition and/or physical structure. vegetative composition and/or physical structure.  Here defined as: line drawn between outermost mature trees at trailheads at an open area. mature trees at trailheads at an open area.  Trampling  Trampling by humans and horses  Use of mountain bikes  Mowing and trimming of pathways

University of GothenburgUniversity of Alberta Study areas Study areas 1.Elk Island National Park 2.Strathcona Wilderness Centre 3. Cooking Lake-Blackfoot Provincial Recreation Area Recreation Area 1 3 2

University of GothenburgUniversity of Alberta Regional context  Boreal mixed-wood forest  Forest canopy dominated by:  trembling aspen (Populus tremuloides)  balsam poplar (Populus balsamifera)

University of GothenburgUniversity of Alberta Study sites (20 trails)  6 trails in Elk Island National Park  6 trails at Strathcona Wilderness Centre  8 trails in Cooking Lake-Blackfoot Area Restrictions for selection of study sites (trails)  Trails should have open-habitat edge at trailheads. trailheads.  Trails should be in forest patches with minimum diameter of 120 m. diameter of 120 m.  No elevation gradients in the area of the trails.

University of GothenburgUniversity of Alberta 60 m Open area 30 m Trailhead Forest Trail Forest Forest patch: 120 m Edge 0 m 15 m Outline of study site Positions On Next Off path to path path Distances from trailhead Sampling plot for vegetation Open area Forest patch: 120 m

University of GothenburgUniversity of Alberta Trampling intensity (use level)  Every trail classified within 3 different use levels = current trampling intensities of vegetation on paths. of vegetation on paths.  Use level 1 = low trampling intensity  Use level 2 = moderate  Use level 3 = high

University of GothenburgUniversity of Alberta Trail, low trampling intensity Trail, moderate trampling intensity Trail, high trampling intensity Examples of trails with different trampling intensities (use levels)

University of GothenburgUniversity of Alberta Measurements taken in every sampling plot for vegetation  Percentage cover of understory species, vascular plants only, 7 different classes.  Canopy cover north and south of every and south of every plot. Densiometer used plot. Densiometer used for measurements. for measurements. Sample plot: Rectangle, size: 0.5 m 2 0.5x1 m or 0.25x2 m

University of GothenburgUniversity of Alberta Stated hypotheses I The Vegetation Structure, Composition and The Vegetation Structure, Composition and Diversity differ: Diversity differ:  at edge of trailheads compared to distances from edge along pathway into forest.  for different positions relative to the paths.  for different trampling intensities (use levels) of the vegetation on the pathways.

University of GothenburgUniversity of Alberta Stated hypothesis II (species composition)  Shade-intolerant species + introduced species more frequent at edge than along trail into forest.  Shade-intolerant + introduced species more frequent on paths than next to and farther off paths.  Proportion of introduced species increased with increasing trampling intensities.

University of GothenburgUniversity of Alberta Statistical analysis – Response variables  Canopy cover = average of canopy cover north and south of every plot  Understory richness = number of vascular plants (understory)species in each plot  Understory richness = number of vascular plants (understory) species in each plot  Total understory cover = addition of cover estimates for all understory species in each plot  Shannon-Wiener diversity index (H’) = understory diversity,distribution of species among plots. Low values, low diversity.  Shannon-Wiener diversity index (H’) = understory diversity, distribution of species among plots. Low values, low diversity.

University of GothenburgUniversity of Alberta Statistical analysis - Model for ANOVA Independent variables Levels Degrees of freedom (df) Distance43 Position32 Use level 32 Distance * use level 1211 Distance * position 1211 Position * use level 98 Distance * position * use level 3635

University of GothenburgUniversity of Alberta Results from ANOVA. Test for variations of mean values for response variables *** Statistical significance Variations in mean values of response variables. Response variables Distance from edge (m) Use Level PositionSite (Use Level (Use Level*Distance) Canopy Cover 30 *** 3.5 *** 31 *** 3.2 *** Total Under- story Cover *** 1.0 Understory Richness 5.6 *** 5.1 *** 84 *** 2.2 *** Understory Diversity (H') 2.8 *** *** 2.0 *** The table contains F values

University of GothenburgUniversity of Alberta Results of ANOVA. Test for interactions among independent variables *** Statistical significance Interactions for independent variables. Response variables Distance * Use level Position* Distance * Position Distance * Position * Use level CanopyCover 9.6 *** 9.8 *** 15 *** 5.3 *** Total Under- story Cover 2.3 *** 14 *** 11 *** 4.3 *** UnderstoryRichness 2.4 *** 21 *** 17 *** 6.2 *** Understory Diversity (H') *** 13 *** 4.8 *** The table contains F values

University of GothenburgUniversity of Alberta Variations in mean values of Canopy Cover Mean of Canopy Cover for Distance and Position Distance from edge (m) Mean of canopy cover (±SE) On paths Next to paths Off paths Trailhead

University of GothenburgUniversity of Alberta Effects of Distance and Position on Total Understory Cover and Understory Richness Mean of Total Understory Cover for Distance and Position Distance from edge (m) Mean of understory cover (±SE) On paths Next to paths Off paths Mean of Understory Richness for Distance and Position Distance from edge (m) Mean of understory richness (±SE) On paths Next to paths Off paths Trailhead

University of GothenburgUniversity of Alberta Effects of Distance and Position on Understory Diversity (H’) Mean of Understory Diversity (H’) for Distance and Position Distance from edge (m) Mean of understory diversity (±SE) On paths Next to paths Off paths Trailhead

University of GothenburgUniversity of Alberta Effects of Position and Use level on Total Understory Cover and Understory Richness Mean of Understory Richness for Position and Use Level Position Mean of understory richness (±SE) Low trampling intensity Moderate trampling intensity High trampling intensity On pathNext to path Off path Mean of Total Understory Cover for Position and Use Level Position On pathNext to path Off path Mean of understory cover (±SE) Low trampling intensity Moderate trampling intensity High trampling intensity

University of GothenburgUniversity of Alberta Effects of Position and Use level on Understory Diversity (H’) Mean of Understory Diversity (H’) for Position and Use Level Position On pathNext to path Off path Mean of understory diversity (±SE) Low trampling intensity Moderate trampling intensity High trampling intensity

University of GothenburgUniversity of Alberta Ordinations – Understory Composition Ordinations – Understory Composition  To examine patterns in understory vegetation composition in relation to distance, use level and composition in relation to distance, use level and position. position.  Vegetation plots close to each other in ordination diagram are similar in species composition. diagram are similar in species composition.  CA (Correspondence Analysis) performed first, inconclusive results. DCA (Detrended CA) used instead. inconclusive results. DCA (Detrended CA) used instead.

University of GothenburgUniversity of Alberta On path Next to path Off path Ordinations (DCA) Vegetation plots (positions) Axis 1 Axis 2 Eigenvalues Length of gradient Cumulative % variance of species data Sum of all eigenvalues 15.5 Total number of understory species found: 104.

University of GothenburgUniversity of Alberta Ordinations - Understory Composition  Results  Different for vegetation plots at positions on paths compared to positions next to paths and far off into the forest. compared to positions next to paths and far off into the forest.  No variations in composition for trails with different trampling intensities (use levels).  No variations in composition for different distances from the trailhead along paths into forest.

University of GothenburgUniversity of Alberta Percentage of frequently occurring understory species Introduced species Shade-intolerant herb Shade-intolerant grass Shade-intolerant shrub Shade-tolerant herb Shade-tolerant shrub On path Next to and off path Ordinations - Understory Composition (cont.) Good news: Next to and off paths, no introduced species among frequently occurring species. Understory types frequently occurring on paths versus next to and off paths

University of GothenburgUniversity of Alberta Understory species frequently occurring on paths Common nameScientific nameSpecies groups Awned wheat grassAgropyron trachycaulumShade-intolerant grass. Kentucky bluegrassPoa pratensisShade-intolerant grass. Hairy wild ryeElymus innovatusShade-intolerant grass. Fringed bromeBromus ciliatusShade-intolerant grass. Foxtail barleyHordeum jubatumShade-intolerant grass. Tufted hair grassDeschampsia caespitosaShade-intolerant grass. Wild strawberryFragaria virginianaShade-intolerant herb. Common plantainPlantago majorShade-intolerant herb. Hemp-nettleGaleopsis tetrahitShade-intolerant herb. Alsike cloverTrifolium hybridumShade-intolerant herb. White cloverTrifolium repensShade-intolerant herb. Common dandelionTaraxacum officinaleShade-intolerant herb. False melicSchizachne purpurascensShade-intolerant herb. Introduced species in yellow. Names and groups of species from Johnson et al (1995).

University of GothenburgUniversity of Alberta Summary – Outcome of stated hypotheses I The Vegetation Structure, Composition and Diversity differ: at edge of trailheads compared to increasing distances from edge along trail into forest. at edge of trailheads compared to increasing distances from edge along trail into forest. for different positions relative to the trail. for different positions relative to the trail. for different trampling intensities (use levels) of the vegetation on the trails. for different trampling intensities (use levels) of the vegetation on the trails.

University of GothenburgUniversity of Alberta Summary – Outcome of stated hypotheses II Species Composition:  Shade-intolerant species + exotic species more frequent at edge than along trail into forest. frequent at edge than along trail into forest. Shade-intolerant + exotic species more frequent on paths than next to and farther off paths. Shade-intolerant + exotic species more frequent on paths than next to and farther off paths.  Proportion of exotic species increased with increasing trampling intensities.

University of GothenburgUniversity of Alberta Conclusions – alleviation of disturbances Possible remedies:  Vegetation inventories to identify location of significant plants. significant plants.  Monitor locations of rare/threatened species.  Protect these locations from disturbance and new development. development.  Develop facilities for users of horses and mountain bikes to clean away seeds from exotic mountain bikes to clean away seeds from exotic species and decrease the spread of exotic species. species and decrease the spread of exotic species.

University of GothenburgUniversity of Alberta Possible remedies:  Educate users about how to minimize impact of trampling.  Frequently monitor trail conditions. Upgrade wet parts to decrease trampling effects on soil and vegetation. to decrease trampling effects on soil and vegetation.  Design trails to decrease disturbance on vegetation:  Restrict trails to communities most tolerant to trampling and edge effects trampling and edge effects  Close possible access to other evident paths  Plant dense thorny plants, e.g., prickly rose, wild raspberry close to edge to discourage off-trail excursions into forest by hikers. close to edge to discourage off-trail excursions into forest by hikers. Conclusions – alleviation of trampling effects

University of GothenburgUniversity of Alberta Conclusions – alleviation of edge effects Possible remedies:  Plant fast growing species along recently created edges to help speed up growth of buffer vegetation. edges to help speed up growth of buffer vegetation.

University of GothenburgUniversity of Alberta Further research should be done to identify  Species  Communities  Habitats that are particularly important in the three study areas. Specific studies of impact of recreation on these could then be conducted.

University of GothenburgUniversity of AlbertaAcknowledgement I am grateful to:  Dr. Ellen Macdonald, University of Alberta  Dr. Matti Koivula, University of Alberta  Dr. Göran Dave, University of Gothenburg Study facilities and field work support:  Department of Renewable Resources, University of Alberta

University of GothenburgUniversity of Alberta