Ximena Palomeque, Selene Báez and Hans Verbeeck, describe ongoing research on the suitability of native tree species for restoring degraded sites in the southern Andes. Ximena is a Professor in the Agriculture Faculty and researcher at Department of Water Resources and Environmental Sciences at the Universidad de Cuenca in Ecuador. Selene is an Associate Professor in the Department of Biology, National Polytechnic School of Ecuador, and Hans Verbeeck is a Professor in the Faculty of Bioscience Engineering, Department of Environment at Ghent University in Belgium. ximena.palomeque@ucuenca.edu.ec; selene.baez@epn.edu.ec; hans.verbeeck@ugent.be
In recent decades, numerous international and regional agreements have formed the foundation for implementing restoration actions, setting ambitious goals and targets to reverse the degradation of tropical forests. For example, Ecuador has set itself a goal to restore 30,000 hectares between 2022 and 2025 as part of the National Program of Landscape Restoration, including both natural regeneration, sometimes called “passive restoration”, and reforestation, one form of “active restoration”. However, achieving lasting benefits in terms of biodiversity conservation, carbon storage, and other ecosystem services requires robust scientific guidance to ensure the implementation of the best possible restoration practices for such highly complex ecosystems as those found in the mountains of the tropical Andes, one of the world’s biodiversity hotspots, spread across several megadiversity countries, including Ecuador.
Andean forest landscapes are characterized by complex mosaics of different land cover types over relatively small spatial scales. Past experiences in restoration have taught us that forest recovery can be rapid and result in diverse forests, but it can be slowed down and even hindered by historical land-use practices. In particular, aggressive competitors such as invasive nonnative grasses (e.g., Festuca arundinacea, Setaria sphacelata, both introduced as fodder for livestock), and the cosmopolitan bracken fern (e.g., Pteridium arachnoideum) often impede the natural recovery of forests, especially in abandoned pastures or areas that have been repeatedly burned. Moreover, the historical use of introduced, fast-growing tree species for reforestation in the Andean region has led to extensive monocultures of Pinus spp., Eucalyptus spp., or Acacia spp., which have had disastrous consequences for local biodiversity by profoundly altering ecosystem dynamics. Given the need for information on efficient and effective reforestation practices using native tree species from the Andes of Ecuador, a large part of our research program aims to address critical knowledge gaps and provide clear guidelines for successful reforestation practices and policies.
To some extent, the extensive use of non-native species for reforestation reflects our limited knowledge of the diversity and potential of native Andean species when intentionally planted. This knowledge gap has hindered the production of adequate seeds and seedlings for use in local reforestation projects. Although some progress has been made in the last decade, a comprehensive understanding of the germination requirements and rates of plant establishment after planting of the most common native Andean tree species is still lacking. In order to bridge this knowledge gap, the Forest Ecology and Seed Laboratory at Universidad de Cuenca, researchers at the Department of Biology at Escuela Politécnica Nacional of Ecuador, the Department of Biology at Pontificia Universidad Católica del Ecuador, and the CAVELab at Gent University (UGENT) in Belgium collaborate to explore various aspects of reforestation using native trees and shrubs. To date, we have gathered experimental data on more than 25 Andean woody species, focusing on seed propagation in laboratory and nursery conditions, as well as the performance of outplanted seedlings on degraded lands.
As a natural progression, we are now conducting experimental research to assess how different outplanted native plant species perform in the field across environmental gradients. Additionally, we are evaluating the potential for carbon sequestration and biodiversity recovery in past reforestation projects, considering factors such as different types of human disturbance, environmental conditions, and landscape-scale attributes. Our findings indicate that landscapes with high natural forest cover have enhanced rates of aboveground biomass and biodiversity accrual, thanks to increased tree survival, sapling recruitment, and animal seed dispersal. In addition, as expected, undisturbed reforested areas recover faster than areas subjected to occasional cattle ranching. These research approaches encompass diverse levels of biological organization, employing a variety of research tools to study and compare plant species, plant communities, and ecosystem processes.
Landscape mosaic illustrating the various land uses found in the area known as “Santa Rosa” in Sevilla de Oro, located at 2300 m a.s.l., Azuay province. Photo: Sebastián Tello.
Seed germination tests of native species in the plant growth chamber at Seed Lab, Universidad de Cuenca in Ecuador. Temperature of 9°C (night) and 12°C (day) under cycles of 12 h of alternating light and darkness. Photo: Ximena Palomeque.
Currently, our main research projects on both approaches to restoration, “active” and “passive”, are led by doctoral students. In 2020, Franklin Marin, a PhD student at the CAVELab, UGENT, Belgium, initiated a large-scale reforestation experiment along an elevation gradient of 2,000 m a.s.l. in southern Ecuador. This experiment involved the planting of over 7,000 individuals from five native woody species, namely Oreocallis grandiflora, Hedyosmum luteynii, Weinmannia fagaroides, Morella pubescens, and Vallea stipularis. The groundwork for the experiment was laid two years earlier when we collected and germinated seeds from a diverse pool of mother trees. Four treatments were implemented, including grass removal and artificial shade, to examine their effects on seedling survival, performance, and species-level trait-plasticity. Weather stations were installed at each study site to monitor conditions that could influence seedling performance over time. This study aims to shed light on the suitability of native species for reforestation projects in sites with varying environmental conditions and interspecific competition. Furthermore, we seek to gain insights into the functional traits that render tree species especially suitable for early stages of forest recovery, which may allow us to generalize our findings to a wider range of Andean tree species under scenarios of natural regeneration or reforestation.
Seedlings of five native species growing in the greenhouse at Universidad de Cuenca in Ecuador. Photo: Ximena Palomeque.
Reforestation experiment using the five native species named in the text on abandoned pastures, Irquis experimental farm, Universidad de Cuenca; located at 2800 m.a.s.l., Azuay province. Photo: Geomatics Lab, Facultad de Ciencias Agropecuarias, Universidad de Cuenca.
Franklin Marín (PhD student) and Selene Báez (EPN) near the weather station and ozone diffusion tubes in the reforestation experiment, Irquis experimental farm, Universidad de Cuenca, Azuay province. Photo: Ximena Palomeque.
A parallel research project led by Gabriela Maldonado, a PhD student at the University of Cuenca, explores the functional composition and diversity of woody plants along gradients of anthropogenic disturbance and across environmental conditions. Gabriela conducts a reforestation experiment using several key species (e.g., Oreocallis grandiflora), with functional traits (e.g., cluster root formation) that could facilitate the establishment of diverse sets of species under scenarios of natural regeneration or reforestation. These “restoration nuclei” could play a crucial role in reestablishing networks of pollinators in restored ecosystems, particularly as some of these species are essential resources for hummingbirds. Her research is conducted within the framework of the Experimental Network Ecology and Restoration, EXPER-NET project, which also involves researchers from the Swiss Federal Research Institute (WSL) and Universidad del Azuay.
Oreocallis grandiflora (Proteaceae), commonly known as gañal is one of the five native tree species used in the reforestation experiments. This species, the only member of its genus, is found only in the high Andes of Peru and Ecuador. Hummingbirds, several types of insects, and even rodents pollinate the flowers of this tree due to its generous production of nectar. Photo: Boris Tinoco.
Gabriela Maldonado (PhD student at University of Cuenca) and Sebastian Tello, Director of the Latin America Department at the Missouri Botanical Garden visiting the observational plots and discussing natural regeneration of degraded pastures at the Irquis experimental farm. To the left, non-native tree species, and in the back, hills with secondary forests. Photo: Selene Báez.
The ongoing research projects have also contributed to scientific training and cultural exchange involving numerous MSc students and dozens of undergraduates. We aim to broaden our impact on the scientific capacity of Ecuadorian and international students by extending our collaborations with scientific groups based in Germany, UK, Switzerland and USA, as well as by fostering exchange programs and field summer courses that focus on specific topics of montane forest ecology and restoration ecology.
We emphasize the significance of international scientific collaborations and funding partners (mainly VLIR-UOS, Belgium) in catalyzing this research initiative. These interactions have enabled us to pursue innovative research in the context of restoration, with direct implications for restoration practices and policy making. Due to the need for solid scientific information to foster natural regeneration and hands-on restoration of Andean forests, several national and international institutions have become close allies of our research group. These organizations comprise local and international NGOs, water funds, electricity production companies such as BOS+, MCF, FONAPA, CELEC, ELECAUSTRO and – most recently – the Missouri Botanical Garden.
This video presents more complete information about one of the projects; and click here for the announcement of the 2023 field course “Linking plant functional traits and ecosystem function in tropical montane forests”. If you require additional information, please do not hesitate contacting the authors of this blog post.
Natural History of Ecological Restoration 