Long-Term Population Trends on Brown Hare in Intensively Used

Long-term Population Trends on Brown Hare in Intensively Used Agricultural Landscape, Lower Saxony, Northern Germany Egbert Strauss1,2, Ulrich Voigt1, Inga Klages1,2, Katrin Ronnenberg1 1 Institute for Terrestrial and Aquatic Wildlife Research University of Veterinary Medicine Hannover, Foundation 2 Hunting Association of Lower Saxony

The project is supported by funds of the Lower Saxony Ministry of Food, Agriculture and Consumer Protection. How many are we ?

objectives  monitoring of hare populations on different scales and on different methods  comparison on survey and census data set

census and survey in Lower Saxony

. wildlife survey since 1991 . spotlight counts (hares) since 1994

. hunting bag since 1958 Wildlife survey data 1991 - 2016

annual questionnaire © piclease Kaminski • on several game species • ~ 9,200 „private“ hunting grounds and © piclease Brillen 150 state forest districts are

questioned annually about: Lettow

• occurrence piclease

 participation 1994 – 2016: 80 - 90 % = 7,600 – 8,500 hunting grounds

. 48,000 km² . 9,200 hunting grounds . intensive agriculture Study Region Lower Saxony

North-West German Lowland . forest: app. <10 % . high soil quality . wheat, maize, grassland

Lüneburg Heath . forest: app. 33% . low soil quality . maize, rape, barley

Börde . forest: app. <10 % . very high soil quality . wheat, maize, sugar beet, rape

Weser and Harz Mountains . forest: app. 33% . low mountain range (100 -1100 m ASL) . middle soil quality . wheat, maize, rape Hare Population 1991 - 2016 assessed hare population in 2006 7,500 to 8,200 hunting grounds

Ems-Weser-Marsch

Ostfriesl, Oldbg & Osnab. Raum Elbe-Niederung Börde & Weser-Aller-Flachland

Stader Geest & Heide Weserbergland & Harz

N 20 Geometrische Grundlage: Nds. Landesamt für Ökologie - Geosum - 0 10 20 30 40 50 Km (Geosumserver Nds. Umweltministerium, Stand: 2002)

km² 15 /

10 Hares Hares

0 Hare Population 1991 - 2016

assessed hare population in 2016 7,500 to 8,200 hunting grounds

Ems-Weser-Marsch Ostfriesl, Oldbg & Osnab. Raum

Elbe-Niederung Börde & Weser-Aller-Flachland

Stader Geest & Heide Weserbergland & Harz

Datenquelle: Wildtiererfassung Niedersachsen (WTE), 20 Landesjägerschaft Niedersachsen e.V., gefördert durch Jagdabgabemittel des Landes Niedersachsen Kartografische Grundlage: © GeoBasis-DE / BKG2002 0 5 10 20 30 40 50 km ±

km² 15 /

10 Hares Hares

0 Census spotlight counting in randomly selected hunting grounds

nach SALZMANN-WANDELER & SALZMANN 1973, PFISTER & RIMATHE 1979, PEGEL 1986

- in spring and autumn - 2 - 3 counts per season - range of spotlight ca. 150 m - lighting area min. 200 ha Hare population 1994 - 2016 spotlight counts in 5 study areas / km² hares n n 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Survey versus Census comparison on hare population by wildlife survey and spotlight counting 2016 Box plot: estimated hare population of 72 – 235 hunting grounds of 5 counties Lines: spotlight counted hare population in 5 randomly selected study areas

11 70 104

60 1 33 2 38

211 50 234 58 212 2 178 204 40 36 71 145 193 24 n hares / km² 30 178 6 195 20

0 n = 72 n = 130 n = 92 n = 235 n = 108 LK WTM LK BRA LK PE LK H LK HM Summary

 currently hunting bag are not representative of population densities  relative high population densities (20 – 60 hare/km²) in intensively used arable and pasture land  high variances and strong population fluctuations in local population densities  1995 - 2006 in some regions high increase, after 2006 strong decline  in regions with lower population densities moderate fluctuations Conclusion

 hunters can provide cost-effective, long-term and reliable monitoring data by scientific guidance = citizen science  important for scientific studies on large scales  causes of the fluctuations mainly are unknown  census data of small sample size limited representativeness, due to high variances and fluctuations of the populations  hunting management must be based on valid data Thank you for your attention