Optimal management of the rare Gladiolus imbricatus in Estonian coastal meadows indicated by its population structure

Abstract

Questions: What is the best grassland management regime for the threatened plant species Gladiolus imbricatus; is the stage structure of local populations a feasible indicator of the effect of changed management. Location: Coastal meadow system in southwestern Estonia. Methods: The effect of five management regimes was studied in a long-term (three-year) field experiment: (1) mowing in late July, (2) grazing by cattle, (3) grazing by sheep, (4) sheep grazing during the first year and mowing during subsequent years, (5) no management (control). Results: The population density increased significantly in response to the mowing treatment and to the mowing after sheep grazing treatment. The proportion of grazed plant individuals was higher in the sheep-grazed than in the cattlegrazed treatment. Generative and vegetative adult individuals of G. imbricatus were significantly more damaged by cattle herbivory than juveniles. All management regimes shifted the population structure towards a dynamic state where juvenile stages dominate, while the not managed control retained a regressive population structure. Conclusions: Population stage structure was a useful indicator of different management conditions, even in the case where population density did not differ. As indicated by population stage structure, the best management regime for G. imbricatus was either mowing in late July only, or alternation of grazing and mowing in different years.

Population Structure of Osmunda regalis in Relation to Environment and Vegetation: An Example in the Mediterranean Area

“…The relative proportions of ramets in the different stages of development, or "life-stage spectrum", was used as the demographic structure. This method is valuable because the spectrum, which indicates the current demographic status of a population or population structure (Moora et al 2007), is considered by many authors (e.g., Menges 1990;Oostermeijer et al 1994;Hegland et al 2001;Jacquemyn et al 2003) as a much better indicator of the present vitality or viability of a population. Three main types of populations are generally distinguished: i) dynamic populations, characterized by a large proportion of young plants; ii) stable populations, which include a higher proportion of adult plants than young plants; iii) regressive populations, in which adult plants dominate and recruitment of new individuals is impeded (see Oostermeijer et al 1994;Aguraiuja et al 2004).…”

Eco-coenotic conditions and structure of Trollius europaeus L. populations in an extrazonal habitat complex (Transylvanian Carpathian foothills)

“…An expeditious approach to demographic studies is a single census per population in a range of plant community types, site conditions or under different management regimes, with the aim to relate them to population stage structure (Endels et al, 2004a,b). The usefulness of this simplified method has proven to be successful in a number of studies on perennial plant species, including rare and endangered species (Aguraiuja et al, 2004;Bissels et al, 2004;Bühler and Schmid, 2001;Colling et al, 2002;Eckstein et al, 2004;Endels et al, 2004a;Geissler and Gzik, 2008;Hegland et al, 2001;Kolehmainen and Mutikainen, 2006;Moora et al, 2007;Oostermeijer et al, 1994). On the basis of population stage structure, one may identify three main types of population: dynamic (expansive), stable and regressive (Rabotnov, 1985).…”

Spatio-temporal variability of Gladiolus imbricatus L. populations in different plant communities near Kraków

“…Then, all the shoots growing within the study plots were counted and tagged with plastic pegs for further observations, carried out in the years 2013-2015. Each year the shoots were inventoried and assigned to a developmental stage according to Moora et al (2007). Also, the distribution of shoots in the study plots was surveyed.…”

“…However, according to Moora et al (2007) the vegetative spread is limited, and production of more than one daughter corm within one season is rare, while reproduction from seeds is common. The aforementioned authors distinguished the following developmental stages: seedlings (individuals with cotyledon), juveniles (individuals forming a nonflowering shoot with one leaf), vegetative (individuals creating a nonflowering shoot with at least two leaves) and generative (individuals creating a flowering shoot).…”

“…The hitherto investigations concerning the sword lily individuals and populations have focused on the natural hybridisation between Gladiolus imbricatus and G. palustris (Szczepaniak et al, 2016), in vitro technologies for micropropagation, multiplication, corm development, somatic embryogenesis and medium-term storage culture (Rakosy-Tican et al, 2012), the influence of management on condition of populations (Moora et al, 2007), the effect of gaps in continuous plant cover and litter on seedling recruitment (Jõgar & Moora, 2008;Kostrakiewicz-Gierałt, 2014a) and the abundance and structure of populations in Molinion caeruleae meadows (Kubikova & Zeidler, 2011;Kostrakiewicz-Gierałt, 2014b).…”