Plant Ecology

, Volume 208, Issue 2, pp 235–244 | Cite as

Can horse riding induce the introduction and establishment of alien plant species through endozoochory and gap creation?



The risk of spreading of alien species to protected forest habitats through recreational horse-back riding was experimentally investigated at Oulanka National Park, north-eastern Finland during 2002–2005. Levels of disturbance, horse manure and seed rain of dwarf shrubs were manipulated in genuine boreal forest habitat. Specifically we asked (i) whether the seeds of alien species can be dispersed to natural forests by horse manure and (ii) whether disturbance in soils and vegetation increases the density of alien species and decrease the density of native species. Manure addition introduced seeds of graminoid and forb species, which were absent elsewhere in the study area. Establishment of the alien species was further enhanced by the disturbance treatment. Germination of natural shrub species was enhanced by disturbance treatment, whereas manure addition had little impact on the native shrubs. The results indicate that alien species may be introduced to natural forests through recreational horse riding, if horses are fed by hay that contains germinable seeds. Soil disturbance enhances the germination of seeds. In practice, the risk of alien species to the biodiversity of natural forests may be relatively small due to the lack of continuous disturbance in these habitats. Instead, the greatest risk is caused by the possibility of alien species to spread via trails to neighbouring, extremely sensitive open habitats.


Alien species Disturbance Horse manure Horse riding Invasive species Protected areas 


  1. Adkison GP, Jackson MT (1996) Changes in ground-layer vegetation near trails in midwestern U.S. forests. Nat Areas J 16:14–23Google Scholar
  2. Alexander F (1946) The rate of passage food residues through the digestive tract of the horse. J Comp Pathol 56:266–268Google Scholar
  3. Archer SR, Smains FE (1991) Ecosystem-level processes. In: Heitschmidt RK, Stuth JW (eds) Grazing management: an ecological perspective. Timber Press, Portland, OR, pp 109–139Google Scholar
  4. Benninger-Truax M, Vankat JL, Schaefe RL (1992) Trail corridors as habitat and conduits for movement of plant species in Rocky Mountain National Park, Colorado, USA. Landsc Ecol 6:269–278CrossRefGoogle Scholar
  5. Braithwaite RE, Lonsdale WM, Estbergs JA (1989) Alien vegetation and native biota in tropical Australia: the impact of Mimosa pigra. Biol Conserv 48:189–210CrossRefGoogle Scholar
  6. Campbell JE, Gibson DJ (2001) The effect of seeds of introduced species transported via horse dung on vegetation along trail corridors. Plant Ecol 157:23–35CrossRefGoogle Scholar
  7. Chambers JC, MacMahon JA, Haefner JH (1991) Seed entrapment in alpine ecosystems: effects of soil particle size and diaspore morphology. Ecology 72:1668–1677CrossRefGoogle Scholar
  8. Chapman HM, Bannister P (1990) The spread of heather (Calluna vulgaris) into indigenous plant communities of Tongariro National Park. N Z J Ecol 14:7–16Google Scholar
  9. Cole DN, Landres PB (1996) Threats to wilderness ecosystems: impacts and research needs. Ecol Appl 6:168–184CrossRefGoogle Scholar
  10. Cosyns E, Hoffmann M (2005) Horse dung germinable seed content in relation to plant species abundance, diet composition and seed characteristics. Basic Appl Ecol 6:11–24CrossRefGoogle Scholar
  11. Couvreur M, Cosyns E, Hermy M et al (2005) Complementarity of epi- and endozoochory of plant seeds by free ranging donkeys. Ecography 28:37–48CrossRefGoogle Scholar
  12. Dale D, Weaver T (1974) Trampling effects on vegetation of the trail corridors of North Rocky Mountain forests. J Appl Ecol 11:767–772CrossRefGoogle Scholar
  13. Danserau P, Lems K (1957) The grading of dispersal types in plant communities and their ecological significance. Contributions l′ institute bot. l′ Universite Montrèal 71:1–52Google Scholar
  14. Eriksson O, Fröborg H (1996) “Windows of opportunity” for recruitment in long-lived clonal plants: experimental studies of seedling establishment in Vaccinium shrubs. Can J Bot 74:1369–1372CrossRefGoogle Scholar
  15. Hämet-Ahti L, Suominen J, Ulvinen T et al (1998) Retkeilykasvio, 4th edn. Finnish Mus Nat Hist, Bot Mus, p 656 (in Finnish)Google Scholar
  16. Hammitt WE, Cole DN (1987) Wildland recreation: ecology and management. Wiley, New YorkGoogle Scholar
  17. Harmon GW, Keim FD (1934) The percentage and viability of weed seeds recovered in the faeces of farm animals and their longevity when buried in manure. J Am Soc Agron 28:762–767Google Scholar
  18. Hautala H, Tolvanen A, Nuortila C (2001) Regeneration strategies of dominant boreal forest dwarf shrubs in response to selective removal of understorey layers. J Veg Sci 12:503–510CrossRefGoogle Scholar
  19. Hobbs RJ, Humphries SE (1995) An integrated approach to the ecology and management invasions. Conserv Biol 9:761–770CrossRefGoogle Scholar
  20. Holm S (1979) A simple sequentially rejective multiple test procedure. Scand J Stat 6:65–70Google Scholar
  21. Janzen DH (1982) Differential seed survival and passage rates in cows and horses, surrogate Pleistocene seed dispersal agents. Oikos 38:150–156CrossRefGoogle Scholar
  22. Janzen DH (1984) Dispersal of small seeds by big herbivores: foliage is the fruit. Am Nat 123:338–353CrossRefGoogle Scholar
  23. John MK (1970) Colorimetric determination of phosphorous in soil and plant materials with ascorbic acid. Soil Sci 100:214–220CrossRefGoogle Scholar
  24. Krysl LJ, Hubbert ME, Sowell BF et al (1984) Horses and cattle grazing in the Wyoming Red Desert, I. Food habitats and dietary overlap. J Range Manage 37:72–76CrossRefGoogle Scholar
  25. Landsberg J, Logan B, Shorthouse D (2001) Horse riding in urban conservation areas: reviewing scientific evidence to guide management. Ecol Manag Rest 2:36–46CrossRefGoogle Scholar
  26. Liddle M (1997) Recreation ecology: the ecological impact of outdoor recreation and ecotourism. Chapman & Hall, LondonGoogle Scholar
  27. Liddle MJ, Chitty LD (1981) The nutrient-budget of horse tracks on an English lowland heath. J Appl Ecol 18:841–848CrossRefGoogle Scholar
  28. McClaran MP, Cole DN (1993) Packstock in wilderness: use, impacts, monitoring, and management. General technical report INT-301, Intermountain Research Station, USAGoogle Scholar
  29. Mouissie AM, Vos P, Verhagen HMC et al (2005) Endozoochory by free-ranging, large herbivores: ecological correlates and perspectives for restoration. Basic Appl Ecol 6:547–558CrossRefGoogle Scholar
  30. Newsome D, Cole DN, Marion JL (2004) Environmental impacts associated with recreational horse-riding. In: Buckley R (ed) Environmental impacts of ecotourism. CAB International, Australia, pp 61–82CrossRefGoogle Scholar
  31. Reichard SH, Hamilton CW (1997) Predicting invasions of woody plants introduced into North America. Conserv Biol 11:193–203CrossRefGoogle Scholar
  32. Rogers GM (1991) Kaimanawa feral horses and their environmental impacts. N Z J Ecol 15:49–64Google Scholar
  33. Saunders DA, Hobbs RJ, Margules CR (1991) Biological consequences of ecosystem fragmentation: a review. Conserv Biol 5:18–32CrossRefGoogle Scholar
  34. SPSS Inc (2003) SPSS base 12.0 user’s guide. SPSS Inc, Chicago, ILGoogle Scholar
  35. Stiles EW (2000) Animals as seed dispersers. In: Fenner M (ed) Seeds: the ecology of regeneration in plant communities, 2nd edn. CAB International, Australia, pp 111–124CrossRefGoogle Scholar
  36. Usher MB (1988) Biological invasions of nature reserves: a search for generalisations. Biol Conserv 44:119–135CrossRefGoogle Scholar
  37. Vallentine JF (1990) Grazing management. Academic Press, San Diego, CA, p 533Google Scholar
  38. Vander Noot GW, Symons LD, Lydman RK et al (1967) Rate of passage of various feedstuffs through the digestive tract of horses. J Animal Sci 26:1309–1311Google Scholar
  39. Weaver T, Dale D (1978) Trampling effects of hikers, motorcycles and horses in meadows and forests. J Appl Ecol 15:451–457CrossRefGoogle Scholar
  40. Wenny D (2001) Advantages of seed dispersal: a re-evaluation of directed dispersal. Evol Ecol Res 3:51–74Google Scholar
  41. Westman WE (1990) Park management of introduced plant species: problems and issues. Conserv Biol 4:251–260CrossRefGoogle Scholar
  42. Whinam J, Comfort M (1996) The impact of commercial horse riding on sub-alpine environments at Cradle Mountain, Tasmania, Australia. J Environ Manage 47:61–70CrossRefGoogle Scholar
  43. Whinam J, Cannell EJ, Kirkpatrick JB et al (1994) Studies on the potential impact of recreational horse riding on some alpine environments of the Central Plateau, Tasmania. J Environ Manag 40:103–117CrossRefGoogle Scholar
  44. Willis KJ, Birks JB (2006) What is natural? The need for a long-term perspective in biodiversity conservation. Science 314:261–265CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2009

Authors and Affiliations

  1. 1.JAMK University of Applied SciencesJyväskyläFinland
  2. 2.Oulanka Research StationUniversity of OuluKuusamoFinland
  3. 3.Finnish Forest Research Institute, Muhos Research StationMuhosFinland

Personalised recommendations