University of Hamburg LIFE Balt Coast Final Seminar

University of Hamburg LIFE Balt. Coast – Final Seminar Ecology of Apium repens Germination and survival of Apium repens in „coastal conditions“ Antonia Wanner, Sandra Burmeier, Jan Schwerdtfeger & Kai Jensen WG Applied Plant Ecology, Biocentre Klein Flottbek, University of Hamburg antonia. wanner@uni-hamburg. de kai. jensen@uni-hamburg. de Department of Biology

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Outline § § § Apium repens: Who is it? • Biology • Distribution and threat Guiding questions Habitat requirements • Hydrology • Soil conditions Experimental ecology • Interspecific competition • Field: Herbivory and vegetation gaps • Germination, dormancy, dispersal (Re)Introduction: Establishment of new populations • Experimental design • Establishment success Conclusions A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Einleitung Ökologie Habitat Experimental Standortecology Ansiedlung (Re)Introduction Conclusions Ausblick Apium repens: Who is it? § § § Characteristics • Perennial, evergreen Umbellifer • 10 -30 cm height • Reproduction by seeds and runners Threat and protection status • Has always been rare In Schleswig-Holstein • Pronounced decline in the last decades only one recent • Listed in Annex II & IV of the Habitats population! Directive, Red Lists (D and SH: 1 = threatened withinextinction), (Status 2006) legally protected in D Range • in Europe from GB to Portugal • Germany: 4 main areas of distribution A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Guiding questions § Is Apium repens rare due to • …specific habitat requirements? • …low competitive ability? • …narrow regeneration niche? • …dispersal limitation? § § How can we protect present populations? (How) can we establish new populations? A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Site conditions: Hydrology, soil parameters § Hydrology: Groundwater levels • Fehmarn, Sundwiesen • Groundwater logger, 1 year § Soil parameters • 20 populations in Northern Germany • p. H, carbon content, macro nutrients § Ellenberg Indicator values • 85 vegetation relevés from Northern Germany • Weighted means of the vegetation vs. Apium repens A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Site conditions: groundwater levels § Strong fluctuations during the year § Several weeks of submergence in spring § Summer water level: 40 to 50 cm below ground Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Site conditions: Soil parameters § § § p. H-value ± neutral Narrow C/N-ratio Wide range of carbon and nutrient contents Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions § L- and N- values of Apium high, higher than that of the vegetation § High range of F- and Nvalues of the vegetation Weighted mean Ellenberg value Site conditions: Ellenberg Indicator values Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Site conditions: Summary • Edaphic requirements rather unspecific • Characteristic factors: – Disturbance (Grazing, mowing, wave action, camping…. ) – Fluctuating water levels Habitat requirements not very specific A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: competition, establishment § § § Apium repens under „coastal conditions“? Flooding and salinity tolerance • Water regime: fresh vs. brackish water (10‰) • Submergence: 0, 2, 4, 8, 2 x 2 weeks Disturbance and interspecific competition • Disturbance regime: mowing vs. control • Competition with Ranunculus repens Establishment in the field • Transplant experiment on the island Fehmarn • Vegetation gaps (yes/no) and herbivory (yes/no) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: Flooding tolerance • Submergence by freshwater is tolerated (but: loss of vitality!) • Submergence by saltwater (10‰) leads to death Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: disturbance and competition § Competition by R. repens and disturbance by mowing reduce biomass of A. repens § No interaction between factors Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: Establishment in the field Grazing no yes Closed vegetation canopy yes no A. Wanner, S. Burmeier, J. Schwerdtfeger & K. n = 25 LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: Establishment in the field § No significant differences between the groups, but § Initially higher mortality of grazed plants § Later, higher mortality of ungrazed plants Burmeier & Jensen (2009) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Flooding, competition: Summary § Apium repens under „coastal conditions“? • Very tolerant to submergence, • but not by salt water (long-term) § Competition: • Apium repens depends on disturbances Low competitive ability! A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Experimental ecology: Germination & dispersal § Temperature requirements • Thermogradient-Incubator • 7 levels of temperature (from 5 °C to 35 °C) § Dormancy and light requirements • Stratification (cold-wet treatment, yes/no), light (yes/no) • Constant vs. fluctuating temperature (15, 20, 5/15, 10/20 °C) § Flooding tolerance of germination • 4 flooding regimes + control 1 x 0, 5; 1 x 1; 1 x 2; 2 x 1 weeks § Dispersal ecology: Seed bank, seed buoyancy A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Germination ecology: Temperature requirements § § § Germination at 5 - 35 °C Optimum at 20°C Reduction at high (and low) temperatures Burmeier & Jensen (2008) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Germination ecology: Fluctuating temperatures § Seeds with primary dormancy show reduced germination at constant temperature Burmeier & Jensen (2008) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Germination ecology: Dormancy and light requirement § § § Light requirement with primary dormancy Dormancy is broken by cold-wet stratification Stratified seeds do not need light for germination Burmeier & Jensen (2008) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Germination ecology: Flooding tolerance § Gemination possible during flooding § Highest germination at constant conditions Burmeier & Jensen (2008) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Regeneration ecology: Summary § § Cold-wet statification or light is required for germination Also germinate during or after flooding Germination requirements not highly specific § Seed bank: • Viable seeds were found in the top soil (-5/-10 cm depth) at least short-term persistent seed bank § Dispersal: • Seeds can float > 50 days (in the greenhouse), but sink with heavy rainfall • sites mostly near small (vernal) water bodies short-distance dispersal by water (also ramets) Seed production limited (? ) Dispersal limition (? ) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions How can we protect present populations? • Maintain (or improve) hydrology • Maintain disturbance regime • Create gaps in autumn to enhance autumn germination (? ) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Establishment of new populations § 3 Sites close to the island of Fehmarn • Eichholzniederung (EH), Hohwacht (HW), Neustädter Binnensee (NB) • Planting in 2007 (EH, HW) and 2008 (NB) § Experimental design • Creation of small water bodies in large-scale grazing landscapes • Grazing (yes/no) • Each 3 transects along a hydrological gradient • 3 „plant types“ (seedlings, runners, sods) • Planting of 200 individuals per site § Monitoring • Monthly monitoring between May and October 2007 to 2010 A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Establishment of new populations: Sites Eichholzniederung Fehmarn Sundwiesen Hohwacht Neustädter Binnensee A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Establishment of new populations: Experimental design Kleingewässer small water body Hohwacht fence Eichholzniederung A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology Conclusions (Re)Introduction Grazing and cover 2007 June July 2007 August 2007 Cover on 25 x 25 cm² [%] June 2007 September 2007 October 2007 Hohwacht Eichholzniederung ungrazed A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Hydrology and cover 2007 Juni July 2007 August 2007 September 2007 Oktober October 2007 Cover on 25 x 25 cm² [%] June 2007 Hohwacht Eichholzniederung 1: high 5: low A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Plant type and cover 2007 June 2007 July 2007 Juli August 2007 August September 2007 Sept. October 2007 Oktober Cover on 25 x 25 cm² [%] Juni Hohwacht Eichholzniederung 1: Seedlings 2: Runners 3: „Sods“ A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology Conclusions (Re)Introduction Cover from 2007 to 2010 2007 2008 2009 2010 Cover on 25 x 25 cm² [%] Hohwacht Eichholzniederung not planted yet Neustädter Binnenwasser ungrazed A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions § Is Apium repens rare due to • …specific habitat requirements? • …low competitive ability? • …narrow regeneration niche? • …dispersal limitation? § How can we protect present populations? No Yes No Probably Maintain hydrology and disturbances § (How) can we establish new populations? Yes, we can…. (sometimes) • With seedlings, runners or sods • With appropriate hydrology and disturbance regime A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Thank you for your attention! Apium repens! A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Site conditions: Soil parameters Burmeier & Jensen (2009) § § p. H-value ± neutral Narrow C/N-ratio A. Wanner, S. Burmeier, J. Schwerdtfeger & K. § High range of C and nutrient contents fluctuate/deviate strongly LIFE Balt. Coast – Final Seminar 28. 08. 12

Germination ecology: Dormancy and light requirement § § § Light requirement with primary dormancy Dormancy is broken by cold stratification Stratified seeds without light requirement for germination Burmeier & Jensen (2008) A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Einleitung Ökologie Standort Ansiedlung Ausblick Grazing and cover 2008 Cover on 25 x 25 cm² [%] Juni Juli August Septem. Oktober Hohwacht Eichholzniederung ungrazed Wanner, Burmeier, J. Schwerdtfeger & Wiederansiedlung K. LIFE Balt. Coast – Final Seminar K. A. Jensen & S. S. Burmeier NNA – von Tierund Pflanzenarten 28. 08. 12 09. 03. 09

Introduction Habitat Experimental ecology (Re)Introduction Conclusions Summary § § Site conditions • Strong fluctuations of groundwater levels, submergence in spring • p. H close to 7; narrow C/N-ratio; otherwise unspecific Competition, disturbance, flooding tolerance • Low competitive ability, depends on disturbances • tolerant against flooding of freshwater Germination ecology • Germination requirements: primary dormancy, stratification, light requirement, temperature fluctuations, temperature range comparable to other species of Central European wetlands, but: • Germination possible also submerged Establishment of new populations • Impact of management/grazing/mowing, hydrology and year on establishment success • Plant type not relevant A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12

Introduction Habitat Experimental ecology (Re)Introduction Conclusions THM § (Re)Introduction of Apium repens seems possible § Specific knowledge of population ecology and habitat requirements for (re)introduction projects necessary A. Wanner, S. Burmeier, J. Schwerdtfeger & K. LIFE Balt. Coast – Final Seminar 28. 08. 12