The mechanistic basis of changes in community assembly in relation to anthropogenic disturbance and productivity

Anthropogenic disturbance often causes changes in communities. However, the mechanistic basis of these changes remains elusive. As all patterns in community ecology can be understood as a result of four processes (speciation, selection, drift, and dispersal), the effect of disturbance should depend on how disturbance disrupt these processes. We studied the effects of disturbance and productivity on species richness, community composition, and community dispersion (i.e., variation in community composition) in the vegetation of 120 boreal peatlands using null-model approach to determine whether community assembly processes differ between pristine and disturbed sites. Sites represented three p…

Ravinnetason ja ojituksen vaikutus suokasvillisuuden monimuotoisuuteen ja lajikoostumukseen

Lajistollisessa monimuotoisuudessa on havaittavissa ajallista ja paikallista vaihtelua, joka on jo vuosisatojen ajan innoittanut ekologeja selvittämään lajirikkauden määrittäviä tekijöitä. Muun muassa pinta-alan, elinympäristön heterogeenisyyden, energian ja resurssien saatavuuden sekä erilaisten häiriöiden on havaittu vaikuttavan lajistolliseen monimuotoisuuteen. Osa monimuotoisuuteen vaikuttavista prosesseista on yhä huonosti tunnettuja, ja yksittäisen tekijän vaikutusta voi olla vaikea tulkita, sillä eri tekijät ovat keskenään vuorovaikutuksessa. Tämän tutkimuksen tavoitteena oli selvittää suokasvillisuusyhteisöjen avulla, vaikuttavatko resurssit tai häiriö (1) yhteisön lajimäärään (alfa…

Recovery of plant communities after ecological restoration of forestry-drained peatlands

Ecological restoration is expected to reverse the loss of biodiversity and ecosystem services. Due to the low number of well-replicated field studies, the extent to which restoration recovers plant communities, and the factors underlying possible shortcomings, are not well understood even in medium term. We compared the plant community composition of 38 sites comprising pristine, forestry-drained, and 5 or 10 years ago restored peatlands in southern Finland, with special interest in understanding spatial variation within studied sites, as well as the development of the numbers and the abundances of target species. Our results indicated a recovery of community composition 5–10 years after re…

Ravinnetason ja ojituksen vaikutus suokasvillisuuden monimuotoisuuteen ja lajikoostumukseen

Ojituksen ja ennallistamisen aiheuttamat muutokset kasvilajistossa ja –yhteisöissä

The mechanistic basis of changes in community assembly in relation to anthropogenic disturbance and productivity

In the human-dominated world the natural drivers of species diversity, such as productivity and habitat heterogeneity, have been accompanied by anthropogenic disturbance resulting in increased extinction rates at global scale. However, decrease in species richness does not necessarily result in local decreases in species richness. Moreover, species richness provides limited information on processes that cause changes within and between communities, and the mechanistic basis of these changes remains elusive. As all patterns in community ecology can be understood as a result of four processes (speciation, selection, drift, and dispersal), the effect of disturbance should depend on how disturb…