The influence of shoot harvesting on the age structure of Convallaria majalis L. populations

Abstract

<p>This paper presents the structure of developmental stages and the age structure of <em>Convallaria majalis</em> L. populations. The investigation material consisted of individuals and modules from populations in <em>Betulo-Quercetum</em>, <em>Fago-Quercetum</em>, <em>Melico-Fagetum</em> and <em>Tilio-Carpinetum</em>, in which the leaves and inflorescence of <em>C. majalis</em> were cut annually over a period of three years.</p><p>Fifty percent of the <em>C. majalis</em> regional population consisted of mature modules, 20% of juvenile modules, 25% of senile modules and a very small percentage of generative modules. In populations of <em>Fago-Quercetum</em> there are four times more senile modules than juvenile modules, while in <em>Melico-Fagetum</em> the percentage of juvenile modules is four times more numerous than the percentage of senile modules. The average age of modules is 4.7±3.8 years. Three year old individuals dominate in the population, while 10 year or older individuals are very rare.</p><p>In the population disturbed by the three raw material collections, the percentage of juvenile modules was decreased by 50% and the percentage of generative modules was nonexistent. As a result, the average module age is higher than in the undisturbed population. Cutting leaves and inflorescence is an important factor in limiting the recruitment of juvenile modules. The growth of individuals in the disturbed population occurs among older modules, which were able to reproduce before the disturbance occurred. Young individuals (three to four years old) are less numerous in the disturbed population, and the majority of individuals are three to six years old.</p

Survivorship and yield of a harvested population of Forsteronia glabrescens

“…Decreased size and altered population structure are expected consequences in natural populations subjected to exploitation [ 6 , 44 , 45 ]. Mortality caused by exploitation can be either compensatory or additive when it removes individuals [ 8 ], but the effect on survivorship varies when only a portion of the plant is harvested, and can go from compensatory to additive as harvesting intensity increases [ 46 ].…”

What Do Cross-Range Germination, Growth, and Interaction Studies Reveal about the Behaviour of an Expansive Plant Species?

“…Convallaria majalis L., also called the 'lily of the valley' of the Asparagaceae family [68], is a spring clonal geophyte with a relatively thick rhizome, which can survive on slightly drier, well-drained, humus and nutrient-poor soils [78], compared to A. ursinum. It is climate-zonally dominant, mainly in mesophilic deciduous forests and mixed and coniferous forests [79].…”

“…Its nutrient requirements are more moderate, and its growth is much slower than A. ursinum. While C. majalis has an early juvenile stage that lasts six months and a juvenile stage that lasts one to two years, during which time it grows its rhizomes and subsequently its shoots [78], its lifespan as a clonal plant can reach up to 670 years [80] and the arrangement of the ramets is genetically driven [81]. It is more shade-tolerant than A. ursinum because its leaves develop in the spring in moderately shaded forests, and they only wither in the fall.…”

“…In the interaction experiments conducted on nutrient-rich soils (A. ursinum + C. majalis), it is presumed that C. majalis shoots were significantly disadvantaged in all moisture categories because A. ursinum seedlings already had leaves and roots that could immediately grow, while C. majalis had to develop these first from the rhizome, which requires more time [78]. The amount of water supplied did not appear to affect competition in the first year.…”

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“…Decreased size and altered population structure are expected consequences in natural populations subjected to exploitation [6,44,45]. Mortality caused by exploitation can be either compensatory or additive when it removes individuals [8], but the effect on survivorship varies when only a portion of the plant is harvested, and can go from compensatory to additive as harvesting intensity increases [46].…”