Lokalmeteorologiska förhållanden i Västra Ängby, Knivsta : förstudie /

<p>Variation of pollen beetle abundance along within-field (A) and between-field (B) transects as a function of distance (km) to woodland edges. (A) Number of pollen beetles per sampling point within two different OSR fields (fields in complex site, C). (B) Mean number of pollen beetles per field in three transects (in zones S, for simple landscape, and HC, for highly complex landscape). Abundance were measured on 10 OSR plants at each sampling point during three (A) or four (B) consecutive weeks (dates 1 to 4). Trans: Transect.</p

Value of fitted dispersal distance global (D_mean) at each date (D_mean (t_n)) and impact of time on the dispersal (β_dt) for the best model (N°1) and for the best model without field effect (N°7).

<p>Value of fitted dispersal distance global (D_mean) at each date (D_mean (t_n)) and impact of time on the dispersal (β_dt) for the best model (N°1) and for the best model without field effect (N°7).</p

Parameters and modalities used to test the 161 models.

<p>Parameters and modalities used to test the 161 models.</p

Observed pollen beetles mean abundance [±SE] (number for ten plants) by site and date.

<p>Observed pollen beetles mean abundance [±SE] (number for ten plants) by site and date.</p

Map of the four studied sites (Normandy region, France), describing land uses within two kilometers radius buffer around the barycenter of the sampled OSR fields in 2015.Green: woodlands.

<p>Blue: grasslands. Yellow: OSR crops. Diamond: sampled OSR fields. Red lines: between fields transect lines. Red circles single out fields where we followed within-field transects from woodlands over 200 m. We distinguish four sites with differing complexities: Highly Simple: HS (7 fields), Simple: S (4 fields), Complex: C (7 fields), Highly Complex: HC (5 fields). Complexity here is a gradient of woodland surfaces in each sites, simple is a site with few woodlands.</p

Best models obtained out of the 161 models estimating pollen beetles dispersal from woodlands to OSR, constraining in turn each modality (categorical factor type, origin, Field point structure, kernel and site dependant dispersal) leaving other modalities and parameters free, with or without a field effect.

<p>Bold: parameter constrained, allowing a field effect. Underlined: parameter constrained, not allowing a field effect.</p

Landscape characteristics of the four study sites in 2009 (within two kilometers of sampled fields).

<p>Woodland edges are the first 100 m within the woodlands from its edge.</p