Understory vegetation relationships with soil element contents in a northern boreal forest ecosystem near a phosphate massif

• Main Authors: Matkala, Laura, Salemaa, Maija, Bäck, Jaana
• Format: Text
• Language: English
• Published: 2019
• Subjects: Northern Finland
• Online Access: https://doi.org/10.5194/bg-2019-110; https://www.biogeosciences-discuss.net/bg-2019-110/

We studied the relationship of forest understory vegetation with nutrient contents of soil and tree leaves near Sokli phosphate ore in northern Finland, where the soil contains naturally high variation in phosphorus (P) contents. At most study plots boreal dwarf shrubs, bryophytes and lichen formed a dense mat under a mixture of sparsely growing Pinus sylvestris , Picea abies and Betula pubescens . However, some plots were dominated by B. pubescens and had a higher variety and number of forbs and grasses in the understory. The total P content in the soil humus layer explained the abundance and species composition of the vegetation slightly better than the total nitrogen content. The spatial variation in contents of soil elements was high both between and within plots, emphasizing the heterogeneity of soil. High contents of P in the humus layer (max. 2600 mg kg −1 ) were measured from the birch-dominated plots. As the P contents of birch leaves and leaf litter were also rather high (2580 mg kg −1 and 1280 mg kg −1 , respectively), this may imply that the leaf litter of birch forms an important source of P to the soil.