TY - JOUR

T1 - Long-term population dynamics of Dactylorhiza incarnata (L.) Soo after abandonment and re-introduction of mowing

AU - Schrautzer, Joachim

AU - Fichtner, Andreas

AU - Huckauf, Aiko

AU - Rasran, Leonid

AU - Jensen, Kai

PY - 2011/7

Y1 - 2011/7

N2 - The orchid Dactylorhiza incarnata (L.) Soó is a highly polymorphic species listed as endangered in many regional red lists of Central Europe and Scandinavia. The dramatic decline of its populations during recent decades has been caused by the loss and degradation of their natural and semi-natural habitats (fens and wet meadows, respectively) as a result of secondary succession following intensification or abandonment of traditional land use.In this study, we analysed the effects of abandonment and re-introduction of mowing on the long-term (28 years) population dynamics of Dactylorhiza incarnata at Lake Barsbek in northern Germany. In this area, to preserve a remaining population of D. incarnata, an annual mowing regime was re-established in 1981 on site M-1 of the investigated plots after a period of abandonment. Annual mowing was introduced on a second site, M-2, in 1987. Two- to three-year mowing was introduced on a third site, M-3. Site A, abandoned since 1970, was used as a reference. On each of these sites, flowering individuals were counted once a year. Population structure and accompanying vegetation were recorded simultaneously. In 2006, light measurements were carried out in the mowed areas.The D. incarnata population at M-1 increased exponentially during the first 10 years after re-introduction of mowing. Pronounced decreases in the number of flowering individuals were recorded in 1997 and 2003. Population dynamics at M-2 generally resembled the temporal development at M-1. D. incarnata disappeared on site A during the investigation period, while vegetation height and litter layer increased by 60 and 100%, respectively. D. incarnata was able to withstand reduced light availability to a certain extent by increasing its vertical growth (shade avoidance). It is concluded that the maintenance of D. incarnata populations in Central Europe requires continuation or re-establishment of wet meadow management. On previously abandoned sites, an initially higher mowing frequency is recommended. Management intensity can be reduced after phytomass production of the vegetation has declined.

AB - The orchid Dactylorhiza incarnata (L.) Soó is a highly polymorphic species listed as endangered in many regional red lists of Central Europe and Scandinavia. The dramatic decline of its populations during recent decades has been caused by the loss and degradation of their natural and semi-natural habitats (fens and wet meadows, respectively) as a result of secondary succession following intensification or abandonment of traditional land use.In this study, we analysed the effects of abandonment and re-introduction of mowing on the long-term (28 years) population dynamics of Dactylorhiza incarnata at Lake Barsbek in northern Germany. In this area, to preserve a remaining population of D. incarnata, an annual mowing regime was re-established in 1981 on site M-1 of the investigated plots after a period of abandonment. Annual mowing was introduced on a second site, M-2, in 1987. Two- to three-year mowing was introduced on a third site, M-3. Site A, abandoned since 1970, was used as a reference. On each of these sites, flowering individuals were counted once a year. Population structure and accompanying vegetation were recorded simultaneously. In 2006, light measurements were carried out in the mowed areas.The D. incarnata population at M-1 increased exponentially during the first 10 years after re-introduction of mowing. Pronounced decreases in the number of flowering individuals were recorded in 1997 and 2003. Population dynamics at M-2 generally resembled the temporal development at M-1. D. incarnata disappeared on site A during the investigation period, while vegetation height and litter layer increased by 60 and 100%, respectively. D. incarnata was able to withstand reduced light availability to a certain extent by increasing its vertical growth (shade avoidance). It is concluded that the maintenance of D. incarnata populations in Central Europe requires continuation or re-establishment of wet meadow management. On previously abandoned sites, an initially higher mowing frequency is recommended. Management intensity can be reduced after phytomass production of the vegetation has declined.

KW - Ecosystems Research

KW - secondary succession

KW - relative light abailability

KW - shade avoidance

KW - litter production

UR - http://www.scopus.com/inward/record.url?scp=79957470410&partnerID=8YFLogxK

U2 - 10.1016/j.flora.2010.11.008

DO - 10.1016/j.flora.2010.11.008

M3 - Journal articles

VL - 206

SP - 622

EP - 630

JO - Flora

JF - Flora

SN - 0367-2530

IS - 7

ER -