TY  - JOUR
A1  - Tschöpe, Okka
A1  - Wallschläger, Hans-Dieter
A1  - Burkart, Michael
A1  - Tielbörger, Katja
T1  - Managing open habitats by wild ungulate browsing and grazing a case-study in North-Eastern Germany
JF  - Applied vegetation science : official organ of the International Association for Vegetation Science
N2  - Question: Can wild ungulates efficiently maintain and restore open habitats?
 Location: Brandenburg, NE Germany.
 Methods: The effect of wild ungulate grazing and browsing was studied in three successional stages: (1) Corynephorus canescens-dominated grassland; (2) ruderal tall forb vegetation dominated by Tanacetum vulgare; and (3) Pinus sylvestris-pioneer forest. The study was conducted over 3 yr. In each successional stage, six paired 4 m(2)-monitoring plots of permanently grazed versus ungrazed plots were arranged in three random blocks. Removal of grazing was introduced de novo for the study. In each plot, percentage cover of each plant and lichen species and total cover of woody plants was recorded.
 Results: Wild ungulates considerably affected successional pathways and species composition in open habitats but this influence became evident in alteration of abundances of only a few species. Grazing effects differed considerably between successional stages: species richness was higher in grazed versus ungrazed ruderal and pioneer forest plots, but not in the Corynephorus sites. Herbivory affected woody plant cover only in the Pioneer forest sites. Although the study period was too short to observe drastic changes in species richness and woody plant cover, notable changes in species composition were still detected in all successional stages.
 Conclusion: Wild ungulate browsing is a useful tool to inhibit encroachment of woody vegetation and to conserve a species-rich, open landscape.
KW  - Conservation
KW  - Red deer
KW  - Fallow deer
KW  - Succession
KW  - Species richness
KW  - Woody plant
Y1  - 2011
U6  - https://doi.org/10.1111/j.1654-109X.2010.01119.x
SN  - 1402-2001
VL  - 14
IS  - 2
SP  - 200
EP  - 209
PB  - Wiley-Blackwell
CY  - Hoboken
ER  - 
TY  - JOUR
A1  - Tschöpe, Okka
A1  - Tielbörger, Katja
A1  - Burkart, Michael
T1  - Offenlandmanagement auf ehemaligen Truppenübungsplätzen
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Tschöpe, Okka
A1  - Tielbörger, Katja
T1  - The role of successional stage and small-scale disturbance for establishment of pioneer grass Corynephorus canescens
N2  - Question Which mechanisms promote the maintenance of the protected pioneer grass Corynephorus canescens in a mosaic landscape? Which are the interactive effects of small-scale disturbances, successional stage and year-to-year variation on early establishment probabilities of C. canescens? Location Brandenburg, NE Germany. Methods We measured emergence and survival rates over 3 yr in a sowing-experiment conducted in three successional stages (C. canescens- dominated site, ruderal forb site and pioneer forest) under two different regimes of mechanical ground disturbance (disturbed versus undisturbed control). Results Overall, disturbance led to higher emergence in a humid year and to lower emergence in a very dry year. Apparently, when soil moisture was sufficient, the main factor limiting C. canescens' establishment was competition, while in the dry year, water became the limiting factor. Survival rates were not affected by disturbance. In humid years, C. canescens emerged in higher numbers in open successional stages while in the dry year, emergence rates were higher in late stages, suggesting an important role of late successional stages for the persistence of C. canescens. Conclusions Our results suggest that small-scale disturbances can promote germination of C. canescens. However, disturbances should be carefully planned. The optimal strategy for promoting C. canescens is to apply disturbances just before seed dispersal and not during dry years. At the landscape scale, a mosaic of different vegetation types is beneficial for the protected pioneer grass as facilitation by late-successional species may be an important mechanism for the persistence of C. canescens, especially in dry years.
Y1  - 2010
UR  - http://onlinelibrary.wiley.com/doi/10.1111/j.1654-109X.2009.01072.x/full
U6  - https://doi.org/10.1111/j.1654-109X.2009.01072.x
SN  - 1402-2001
ER  - 
TY  - JOUR
A1  - Tschöpe, Okka
A1  - Burkart, Michael
A1  - Tielbörger, Katja
T1  - Habitat management in former military training area by means of Megaherbivores
Y1  - 2002
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Prasse, Rüdiger
A1  - Bornkamm, Reinhard
A1  - Kadmon, Ronen
A1  - Tsoar, H.
T1  - Sukzessionsprozesse in einem Sanddünengebiet nach Ausschluß von Beweidung
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Kadmon, Ronen
A1  - Müller, Monika
A1  - Jeltsch, Florian
T1  - Populationsdynamische Funktionen von Ausbreitung und Dormanz
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Kadmon, Ronen
A1  - Müller, Monika
A1  - Jeltsch, Florian
T1  - Raum-zeitliche Populationsdynamik von einjährigen Wüstenpflanzen
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Kadmon, Ronen
T1  - Relationships between shrubs and annual communities in a sandy desert ecosystem : a three-year study
N2  - A field study was designed to investigate the effect of shrubs on the dynamics and structure of annual plant communities in a sandy desert ecosystem. Densities of emerging and reproductive plants of all annual species were monitored in permanent quadrats located under shrubs and in open areas between shrubs during three successive years; a relatively dry one, a relatively wet one, and a very dry one. A total of 29 species were recorded in the study. Of these, 19 species did not show any evidence for differences in abundance between the two habitats. Nine species exhibited year-to-year variation in their responses to the shrub-opening gradient, being more common in a particular habitat during one year, and showing no response or even an opposite response during a different year. Only one species was consistently more abundant under shrubs throughout the whole study period, and no species was consistently more abundant in the openings. These findings contradict the hypothesis that annual species associated with desert shrub communities can be categorized into distinct groups based on their 'preference' for shrubs vs. openings. Ordination analyses of community-level patterns indicated that annual communities inhabiting the openings were more stable than those inhabiting the shrub habitat. The main lesson from this study is the importance of long-term observations in studies attempting to characterize community-level responses to environmental gradients.
Y1  - 1997
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Kadmon, Ronen
T1  - Temporal environmental variation tips the balance between facilitation and interference in desert plants
N2  - Recently, numerous studies have pointed to the importance of positive interactions in natural communities. There is now a broad consensus that the balance between negative and positive interactions should shift along environmental gradients, with competition prevailing under environmentally benign conditions and positive interactions dominating under harsh conditions. A commonly cited example of the importance of facilitation in harsh environments is the preference of desert annual plants for the areas under the canopy of shrubs. The recognition of apparently positive effects of desert shrubs on annuals, however, has been mostly based on density measurements, while fitness parameters of the understory plants have been ignored. Also, the temporal consistency of such effects has not been previously tested. Based on conceptual ideas about the balance between interference and facilitation, we predicted that positive effects of the shrubs on the understory should dominate in dry years, while in favorable years, negative effects would be stronger. We tested our hypothesis by measuring the direction and magnitude of the shrub effect on demographic responses of four desert annual plant species during four consecutive seasons of differing rainfall. The results contradicted our initial hypothesis. Depending on the species, the effect of the shrubs shifted from either negative to neutral or from neutral to positive with increasing annual rainfall. However, this trend was stronger for the effect of shrubs on plant reproductive success than on their densities. Our data highlight the importance of measuring fitness parameters in studies of plant-plant interactions. We suggest that the negative effects of shrubs on plant fitness were due to rainfall interception, while positive effects were related to increased nutrient availability beneath shrubs. However, the mechanisms by which the shrubs and annuals interact can only be resolved using an experimental approach. Our results contradict previous hypotheses about the relative importance of positive and negative interactions along environmental gradients. A simple conceptual model summarizing the proposed role of rainfall in determining the direction of shrub effects on their understory annuals is presented.
Y1  - 2000
ER  - 
TY  - JOUR
A1  - Tielbörger, Katja
A1  - Kadmon, Ronen
T1  - Indirect effects in a desert plant community : is competition among annuals more intense under shrub canopies?
N2  - An unresolved discussion in contemporary ecology deals with the relative importance of competition along environmental gradients. In deserts, local-scale differences in environmental productivity may be caused by the presence of shrubs, which represent a favorable habitat for annual populations within a nutrient-poor matrix. In this study, we attempted to test the hypothesis that facilitation of desert annuals by shrubs increase the intensity of competition among the annual plants. Such negative indirect effects have so far been ignored in studies about plant-plant interactions. We tested our hypothesis by measuring seedling survival and fecundity of four abundant annual plant species with and without neighbors in open areas and under shrub canopies in a sandy desert area. Our findings did not indicate indirect negative effects of shrubs on their understory annuals. Sensitivity to the presence of neighbors varied between species and surprisingly, the species with the smallest seeds was the only one which was not negatively affected by the presence of neighbors. In contrast to our hypothesis, there was no difference between the habitat types shrubs and openings in absolute and relative competition intensity. Our overall results suggest that negative indirect effects of shrubs are unimportant in determining demographic response of understory annual plants.
Y1  - 2000
ER  -