Environmental changes in biodiversity hotspot ecosystems of
South Ecuador: RESPonse and feedback effECTs (FOR2730)

Resumen:

Uno de los aspectos importantes a considerarse en la producción eficiente de plántulas con fines de restauración es la calidad de semillas y su variabilidad. El objetivo de este estudio fue evaluar los parámetros de semillas de acuerdo con las reglas del “International Seed Testing Association” entre diferentes árboles madre o individuos de siete especies nativas (Cedrela montana, Morella pubescens, Inga acreana, Tabebuia chrysantha, Ocotea heterochroma, Oreocallis grandiflora y Myrcianthes rhopaloides) en dos bosques de montaña del sur del Ecuador. Estas especies fueron seleccionadas por la importancia ecológica, socioeconómica, y su gran potencial para la restauración. De un total de 35 árboles madre de todas las especies, se colectaron las semillas en sus respectivos periodos de fructificación, y en el laboratorio fueron analizados los siguientes parámetros: pureza, peso, contenido de humedad y germinación; adicionalmente se determinó el coeficiente de velocidad de germinación. Los resultados mostraron una similitud intraespecífica en cada especie para la mayoría de los parámetros; no obstante, el peso presentó alta variabilidad intraespecífica para todas las especies. El parámetro germinación obtuvo diferencias entre individuos para C. montana, T. chrysantha, O. heterochroma y M. rhopaloides. En cuanto a la velocidad de germinación, individuos de especies como O. grandiflora e I. acreana mostraron un alto coeficiente en contraste a los individuos de O. heterochroma y M. pubescens. La información generada en este estudio podría ser el primer paso en la formulación de pautas para la producción masiva de plántulas de especies nativas con fines de restauración.

Resumen:

Forest recovery on disturbed areas is of special significance in the Ecuadorian Andes, where deforestation is a serious problem. Natural diachronic succession was evaluated on three large plots or sites, differing in their land use and vegetation composition, one is dominated by grass species on an abandoned pasture (Pasture site), the other two are post-fire vegetation dominated by bracken (Bracken site) and various shrubs (Shrub site). Additionally, we assessed the effectiveness of manual removal of competitive herbaceous species to accelerate forest recovery. Monitoring was done in 2003, 2005 and 2007 on 48 subplots of 116 m2 each recording species richness and woody-species density. Results showed that the Pasture site demonstrated a competitive effect of exotic grasses on woody species recruitment with much lower species recruitment and density, suggesting serious inhibition of natural forest regeneration and an unclear successional trajectory. The Bracken and Shrub sites became significantly similar floristically and there is evidence for a marked facilitation of woody plant recruitment correlated with light availability on the ground. Both sites showed characteristics of classic succession, with Shrub showing a higher species richness and density while late-successional species are poorly represented on the Bracken site. However, NMDS ordination using species density showed that the two trajectories may not be converging towards a common ‘‘final state’’. Manual weeding was ineffective for accelerating forest recovery. These results suggest that the main limiting factor for the recruitment of woody species on the Pasture site is strong grass competition and must be addressed before seed availability, while seed availability seems to be theconstraining factor for Bracken and Shrub site development, thus direct seeding or planting may be effective in accelerating forest recovery.

Resumen:

High landscape diversity is assumed to increase the number and level of ecosystem services. However, the interactions between ecosystem service provision, disturbance and landscape composition are poorly understood. Here we present a novel approach to include uncertainty in the optimization of land allocation for improving the provision of multiple ecosystem services. We refer to the rehabilitation of abandoned agricultural lands in Ecuador including two types of both afforestation and pasture rehabilitation, together with a succession option. Our results show that high compositional landscape diversity supports multiple ecosystem services (multifunction effect). This implicitly provides a buffer against uncertainty. Our work shows that active integration of uncertainty is only important when optimizing single or highly correlated ecosystem services and that the multifunction effect on landscape diversity is stronger than the uncertainty effect. This is an important insight to support a land-use planning based on ecosystem services.