Driving forces of species diversity in unmanaged semi-natural grasslands and pastures

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1 Driving forces of species diversity in unmanaged semi-natural grasslands and pastures Jutta Kapfer, Einar Heegaard, Svein O. Krøgli, Christian Pedersen, Gregory Taff & Wenche Dramstad 57th Annual Symposium of the IAVS, Perth, Australia, September 2014 Photo: Geir-Harald Strand

2 Drivers of change in biodiversity Biodiversity Climate change Habitat loss Invasive species Land-use change Biodiversity in AL Polarisation Intensification «Extensification» AL = Agricultural Landscapes Major threats for habitats such as semi-natural grasslands 2

3 Semi-natural grasslands (SNG) Among most species-diverse communities in the world Close link to long-term, traditional, agricultural land-use Land-use intensification and land abandonment Principal causes of habitat deterioration, fragmentation and BD loss in AL in Europe Need for appropriate design and implementation of conservation management to maintain SNGs 3

4 How important is Effects of herbivory? Land-use change? Cattle Sheep Photo: O. Puschmann Surrounding landscape? for biodiversity in semi-natural grasslands? Photo: O. Puschmann 4

5 Research questions What are the most important predictors of species richness and composition in unmanaged semi-natural grasslands and pastures in Norway? Can the observed diversity patterns be explained by Photos: Oskar Puschmann - Grazer type and grazing intensity? - Spatial configuration of surrounding landscape? - Land-use history? 5

6 wikimedia.org Norway arctic Study area m a.s.l. Bedrock: Siliceous granite/gneiss, calcareous schists/limestones Soil: Sand, clay, peat, silt Mean annual temperature: 5.8 C Mean total annual precipitation: 1621 mm 1km boreal Dataset: The Norwegian monitoring programme for agricultural landscapes (3Q) Grasslands 97 monitoring units á 1km subplots á 8m x 8m 1km 6

7 Floristic data Semi-natural grasslands and pastures Sampling period: Vascular plant presence and abundance 513 species in 569 plots min 5, median 26, max 71 Average species no. per plot: 27 1km 1km Photo: H. Brattli Photo: G. Engan 7

8 Data preparation environmental variables Spatial landscape configuration - All neighbouring AR5* land-cover types - (Patch) Area, distance, shape, circumference - Distance to the sea Land-use history - Land cover types from Economic Map (50 years back) Herbivory - Species: Sheep, goat, cattle, horse, none - Intensity (1-5) Abiotic factors - Climate - Soil moisture (1-5) AR5* land cover types: Fully cultivated land Surface cultivated land Pasture Forest Peat bog Open land Water Glacier, permanent snow Built-up area Transport network area *AR5 is the Norwegian high resolution land resource database 8

9 Patterns in species composition NMDS1 NMDS2 r2 Pr(>r) Grazing intensity Distance to surface cultivated land Distance to transportation corridors Patch shape Spring temperature Summer temperature Distance to sea

10 Variables explaining species richness Estimate Std. Error z value Pr(> z ) X(Intercept) 2.777e e < 2e-16 Grazing intensity e e Elevation 9.174e e Autumn precipitation e e Summer temperature 3.086e e Historical land-use Patch shape 3.852e e Distance to nearest transp e e Distance to nearest forest e e Area of nearest wetland 2.494e e

11 Historical land-use and species richness Historical land-use Average no. species P-value Surface cultivated land Pasture 29 <0.001 Forest 34 <0.001 Open land Wetland Highest species richness in former forest 11

12 Herbivory and species richness G = goat H = horse I = none K = cattle S = sheep Grazing intensity more important for species diversity than grazer type No statistically significant impact of grazing type 12

13 Conclusions Norwegian SNGs influenced by variety of environmental factors Geographic location, patch shape, surrounding landscape structure and land-use intensity most important for species diversity Effects of agricultural management practices reache into adjacent landscape elements Entire landscape needs to be considered when management of particular habitat patch is planned Further research needed Work in progress 13