HÅRNERVMOSSANS PÅVERKAN PÅ LJUNGHEDENS ARTMÅNGFALD: En fältstudie från Sandsjöbackas naturreservat

Abstract

Campylopus introflexus is a moss species that originates from the southern hemisphere and has spread worldwide during the 20th century. Today it is classified as an invasive alien species in many countries, and it has been seen during inventories that it has become widespread in Sweden as well. The purpose of this essay is to contribute to new knowledge about how this moss affects species diversity on Calluna heathlands in Sweden. The study includes both fieldwork and an analysis of scientific literature on the subject, and the question that is answered is if C. introflexus has an impact on species richness in the heather peat. Field data were collected on an Calluna heathland in Sandsjöbacka nature reserve outside Gothenburg, where species in the heather peat were counted and identified, both in places where C. introflexus was present and not. The collected data were tested for normal distribution and equal variances, after which a two-tailed ttest was performed. The result showed a significant difference in the mean number of species found when C. introflexus was present and not. Average number of species found in 0,25m2 squares with C. introflexus was 6,1, while the number of species in squares without C. introflexus was 7.4. When it comes to the number of species found, this is almost a 20% decrease. That indicates that C. introflexus has a negative impact on species richness on Calluna heathlands, but to establish this more comprehensive field studies are required. The literature survey also showed that C. introflexus has a negative impact on species diversity as it forms dense mats that make it difficult for other species to grow there. The invasive moss can also establish itself very quickly in disturbed environments, such as on clearcuts, root rolls or burned ground, which gives it an additional competitive advantage on Calluna heathlands.