Seed production, seed dispersal and seedling establishment of two afromontane tree species in and around a church forest: implications for forest restoration

Abstract

Background: Seed production, seed dispersal and seedling establishment are relevant life phases of plants. Understanding these processes and their patterns is essential to recognize vegetation dynamics and to apply it to forest restoration. Methods: For Olea europaea and Schefflera abyssinica, fecundity was estimated using randomized branch sampling. Seed dispersal and seedling establishment were monitored using spatially explicit seed traps and plots. Dispersal functions were calibrated applying inverse modeling. Results: O. europaea produced more seeds and had longer dispersal distances compared to S. abyssinica. Correlations between observed and predicted number of recruits were statistically significant. Seedlings of the two species showed different niche requirements. Conclusions: The studied species were recruitment-limited due to low dispersal activity or lack of suitable microsites. Restoration relying on natural regeneration should overcome these limitations by increasing disperser visitation and reducing biotic and abiotic stresses.

An Assessment of a Community-Based, Forest Restoration Programme in Durban (eThekwini), South Africa

“…As a result, seedling recruitment is considered to be one of the key factors that determine the success of the long-term vegetation restoration [86]. Restoration habitats that are adjacent to the existing remnant forest are more likely to recover quickly as a result of colonization by animal seed dispersers [18,20,29]. However, the recruitment of animal-dispersed tree seedlings is higher in the established habitats [90].…”

“…An important recommendation emanating from the present study is that reforestation success assessment should be carried out in the early stages of reforestation projects in order to understand the ecological development trajectories and to inform necessary management interventions, to maximise reforestation benefits [18,20,61]. The use of multiple indicators (e.g., vegetation structure, species diversity, ecological processes and IAP cover) also gave valuable insight into the ongoing ecological trajectories and enabled the identification of necessary management interventions.…”

Seed germination in <em>Ormosia macrocalyx</em>, an endangered tropical forest tree

“…Studies and findings about successful seed storage methods should be promoted, because field survival following direct sowing of this endangered species is very low (less than 4 %) (Pérez-Hernández et al 2011). For this reason, the alternatives for conservation of germplasm must include: assisted natural regeneration (passive restoration), protecting the remnants of tropical forest in which it is found (Abiyu et al 2016); or harvesting of the seeds and producing plants in greenhouses for subsequent introduction into the ecosystem in cuestion. Considering that this is a late species with requirements for shade in its first stage of life (Krause et al 2012), it can be transplanted at four months of age in order to maximize its possibility of survival (Villacís et al 2016).…”

“…The fact that seeds remain attached to the fruit on the tree for a long time represents an obstacle to the successful propagation of the tree, since germinative response could be variable and dependent upon seed age. Given the low seed rain, an adequate seed bank cannot be created; it is known that the most appropriate strategy for the restoration of degraded landscapes is recolonization of the native flora through seed banks (Abiyu et al 2016), which are defined as the stock of mature and viable seeds deposited in the soil surface. Ideally, this seed bank should be abundant in order to obtain a high production of seedlings and to guarantee the permanence of the species, and it is also a necessary mechanism for secondary succession (Martins & Engel 2007).…”

Germinación y crecimiento de especies nativas potenciales para reforestación en el estado de Tabasco, México

“…Las semillas tienen de 10 a 13 mm de largo, 10 mm de ancho y 7-8 mm de grosor, con un color rojo brillante (Rudd 1968b, Ochoa-Gaona et al 2008a. Ormosia macrocalyx puede jugar un papel importante en la captura de CO2: Elias y Potvin (2003) (Abiyu et al 2016), el cual es definido como la cantidad de semillas maduras y viables depositadas en la superficie del suelo. Idealmente, este banco de semillas debe ser abundante para obtener una alta producción de plántulas y garantizar la permanencia de la especie y es también un mecanismo necesario para la sucesión secundaria (Martins y Engel 2007).…”