Restoration of ecosystem functions: Seed production in restored and ancient grasslands

Abstract

Questions: Evaluating seed production as a community function in species-rich temperate grasslands, we asked: (a) do ancient and restored grasslands differ in the composition of seed-producing species; (b) do seed-producing species of ancient and restored grasslands differ in their functional traits and habitat origin of their species; and (c) how does seed production change during the season considering management and is seed production different for the whole community and for the subset of species occurring in both types of grasslands? Location: White Carpathian Mountains (Czech Republic). Methods:We assessed the species composition of flowering and fruiting species and collected propagule samples from three ancient and three restored grasslands. From the measured parameters, we estimated seed production for particular fruiting species. We combined these reproductive parameters with data on plant traits and plant status.Results: Flowering species in restored grasslands produced three times higher seed numbers and three times lower seed mass than flowering species in ancient grasslands. At ancient sites, most seeds belonged to meadow specialist species; at restored sites, seeds of ruderal and generalist species prevailed. Prior to mowing, in both grassland types the seed-producing species were characterised by a high capability of clonal reproduction, high leaf dry matter content, and wind pollination. After mowing, seed-producing species were insect-pollinated species at ancient sites. This reflects the dominance of grasses before mowing and of forbs after mowing. Conclusions:Higher seed number, lower seed mass and lower reliance on pollinators in restored grasslands indicate a different ecosystem functionality related to these parameters, in comparison with ancient grasslands. Specifically, seeds act as source for generative regeneration of resident species while resources for pollinators and seed herbivores are reduced. This maintains a differentiation of restored and ancient grasslands not only in terms of species composition but also in their effect on other trophic levels.

Restoring mountain ecosystems: Challenges, case studies and recommendations for implementing the UN Decade Principles for Mountain Ecosystem Restoration

“…Furthermore, overgrazing and water deviation have degraded high-elevation peatlands in the tropical Andes, resulting in loss of water, carbon and vegetation and in extreme soil erosion (Planas-Clarke et al 2020;Suarez et al 2022; United Nations Environment Programme [UNEP] 2022a). Similar pressures, in addition to overuse of fertilizers, have been reported for grasslands in the White Carpathian Mountains in Czechia, and forests in the Dieng Mountains in Indonesia (Marliana and Rühe 2014;Albert et al 2021). Hydrological changes due to shifts in climate may exacerbate the impacts caused by intensive livestock production in high-elevation peatlands in the Andes, causing increased greenhouse gas emissions, and further exacerbating their declining carbon storage capacity (Planas-Clarke et al 2020).…”

Seed Dormancy and Seedling Ecophysiology Reveal the Ecological Amplitude of the Threatened Endemism Picris willkommii (Schultz Bip.) Nyman (Asteraceae)

“…Germination in early autumn and vegetative growth during the cold season can mean a strategy for the development of the basal rosette and the accumulation of energy reserves, taking advantage of the mild winter in the area, which will allow a more vigorous growth when spring arrives [ 26 , 27 , 31 ]. During none of the three years assessed was the emergence of new plants observed in late winter or early spring, except for some sporadic individual, and even though the temperatures and soil moisture levels allowed it, the competition between plants or the shading generated by the plants already installed, of the same or different species, could be the cause [ 19 , 33 , 34 , 35 ]. This competition not only affected the emergence of new plants, but also those that had previously emerged, since only 10–25% of the individuals that emerged in early autumn developed and produced seeds.…”

“…However, despite the fact that Oxalis pes-caprae begins to decrease its physiological activity from the beginning of spring in order to end its annual cycle in early May, there is not enough time for plants of the replaced species to emerge at that time and complete their reproductive cycle before the arrival of summer. Consequently, any alteration of the natural balance of the ecosystem, such as anthropogenic pressure, can lead to changes in the composition and abundance of the species of the new cohort [ 20 , 35 , 39 ] and, therefore, to the replacement of Picris willkommii by other plant species historically present in the area (e.g., some Malva , Chrysanthemum and Diplotaxis species) or by other more recent invaders (e.g., Oxalis pes-caprae and Amaranthus blitoides ). The mere fact of plowing the soil, carried out during the outplanting trial, caused the appearance of abundant individuals of other opportunistic and/or invasive species of the plant community, such as those just mentioned, which surely benefited from soil disturbance.…”