Migratory geese foraging on grassland Case study in the region of Flanders (Belgium) Van Gils B. 1, De Vliegher A. 1, Huysentruyt F. 2, Casaer J. 2 & Devos K. 2 1 Institute for Agricultural and Fisheries Research (ILVO), Merelbeke, Belgium 2 Research Institute for Nature and Forest (INBO), Brussels, Belgium 24 th general meeting of the European Grassland Federation Lublin, 06/06/2012

INDEX 2 Introduction: Migratory geese in Flanders Part I. The need for research Part II. Materials and methods Part III. Results Part IV. Conclusions

3 Introduction: migratory geese in Flanders

4 White fronted goose Anser albifrons Siberia Greylag goose Anser anser & November – March (40,000) October – February (15,000) Geese species & ecology Vildaphoto

5 Pink-footed goose Anser brachyrhynchus Svalbard (Spitsbergen) Flanders (90%) November – February (35,000) Geese species & ecology Distribution of wintering geese in Flanders (Devos et al., 2005) Vildaphoto

6 BRIEF HISTORY & CURRENT SITUATION Migratory geese in Flanders Winter migration towards polder areas in Flanders Intensive monitoring by ecological researchers since 1960 Protection of migratory geese: hunting ceased in 1980 Increase from few thousands to almost 100,000 in 40 years Foraging on grassland, winter wheat, …  Conflict between agriculture and nature conservation  Compensation procedure for farmers (01/09/2009)

7 Part I. The need for research From understanding goose grazing effects towards reconciliation of agriculture with the presence of protected species

8 R ESEARCH GOALS Part I. The need for research 1.How is grassland fodder production affected? 2.How is grass fodder quality affected? 3.What is the level of fertilization by goose droppings? Research questions From understanding goose grazing effects towards reconciliation of agriculture with the presence of protected species

9 Part II. Materials & methods

10 GOOSE DAMAGE ASSESSMENT WITH EXCLOSURES Part II. Materials & methods Total of 20 exclosures on 5 grasslands Grazing intensity assessment: dropping counts (plot + transect)  GD (#/ha) = D (#/m 2 ) * 10,000 (m 2 /ha) / 125 Grass biomass production: plot yield measurements (first cut) Grass fodder quality: NIRS - Near InfraRed Spectroscopy Fertilization effect of droppings Theoretical calculations based on dropping counts & N content Soil sampling on 3 grasslands

11 GOOSE DAMAGE ASSESSMENT WITH EXCLOSURES Part II. Materials & methods Grazed plot

12 Part III. Results of intensive goose grazing

13 S UMMARY OF RESULTS Part III. Results Field codeGDplot (#/ha) GDtransect (#/ha) Yield loss (kg DM/ha) DCP (%) DCF (%) N add (kg N/ha) Klem031,4582, Klem042,2192, Klem055891, Asse036611, Hoek Average1,0081, * -0.9 ** 8.5 GDplot: total of goose days per hectare, based on dropping counts in grazed plots GDtransect: total of goose days per hectare, based on dropping counts on transects DCP: difference in crude protein content (grazed - ungrazed) DCF: difference in crude fiber content (grazed - ungrazed) N add: theoretical nitrogen addition, calculations based on GDtransect * p < 0.05 ; ** p < 0.01 Table 1: Effect of goose grazing on grassland fodder production and quality

14 1.How is grassland fodder production affected? NEGATIVELY, on average 450 kgDM/ha on the first cut (15-20%) 2. How is grass fodder quality affected? POSITIVELY, with slightly elevated crude protein and lower crude fiber content 3. What is the level of fertilization by goose droppings? NEGLIGIBLE, compared to fertilization in conventional practices in Flanders (350 kgN/ha*yr) Part IV. Conclusions

Institute for Agricultural and Fisheries Research Plant Sciences Unit Agriculture and Fisheries Policy Area QUESTIONS?