Merel Jansen

Merel Jansen
Universität Koblenz-Landau · Department of Environmental Sciences

PhD

About

20
Publications
2,776
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85
Citations
Introduction
My research focuses on the sustainable use and restoration of tropical forest resources, in particular non-timber forest products. I aim to identify solutions that can maximize ecological and livelihood benefits. I collect empirical data and use this to parameterize models that simulate processes at individual tree, population and landscape levels. Currently, I am evaluating the potential of agroforests to mitigate deforestation related drought in south-west Amazonia.
Additional affiliations
February 2020 - present
Universität Koblenz-Landau; Universität Kassel; Universität Hamburg
Position
  • PostDoc Position
Description
  • As part of a Swiss National Science Foundation fellowship, I collaborate with the project PRODIGY, and aim to evaluate the potential of the implementation of agroforests to mitigate deforestation related drought in south-west Amazonia
September 2016 - January 2019
ETH Zurich
Position
  • PostDoc Position
Description
  • As lead postdoc on the project SUSTAIN, I evaluated (1) the effect of forest degradation on Brazil nut tree reproductive ecology (2) the potential of non-timber forest products for agroecological restoration approaches The studies were conducted in Madre de Dios, Amazonian Peru
Education
September 2012 - December 2016
Wageningen University & Research
Field of study
  • Tropical forest ecology - Plant Demography
September 2009 - June 2011
Utrecht University
Field of study
  • Environmental Biology - Ecology and Natural Resource Management
September 2005 - August 2008
Utrecht University
Field of study
  • Physics and Astronomy - Theoretical Physics

Publications

Publications (20)
Article
Full-text available
An unanswered question in ecology is whether the environmental factors driving short-term performance also determine the often observed long-term performance differences among individuals. Here, we analyze the extent to which temporal persistence of spatial heterogeneity in environmental factors can contribute to long-term inter-individual variatio...
Article
Full-text available
Natural populations deliver a wide range of products that provide income for millions of people and need to be exploited sustainably. Large heterogeneity in individual performance within these exploited populations has the potential to improve population recovery after exploitation and thus help sustain yields over time. 2.We explored the potential...
Article
Full-text available
Introduction Defoliation and light competition are ubiquitous stressors that can strongly limit plant performance. Tolerance to defoliation is often associated with compensatory growth, which could be positively or negatively related to plant growth. Genetic variation in growth, tolerance and compensation, in turn, plays an important role in the ev...
Article
Full-text available
1. The global food system is causing large-scale environmental degradation and is a major contributor to climate change. Its low diversity and failure to produce enough fruits and vegetables is contributing to a global health crisis. 2. The extraordinary diversity of tropical tree species is increasingly recognized to be vital to planetary health...
Article
Full-text available
Brazil nuts are an economically important non-timber forest product throughout the Amazon Basin, but the forests in which they grow are under threat of severe degradation by logging, road building, agricultural expansion, and forest fires. As a result, many Brazil nut trees grow within a mosaic of young secondary forest, primary forest remnants and...
Article
Full-text available
To maximize trees restoration potential, it is crucial to know where and how. In this study led by Rens Brouwer, we explored the planting performance and productivity of a socio-environmentally highly valuable species from the Amazon, the Brazil nut tree, and compared its planting success across management practices, degraded areas, agroforestry sy...
Article
Full-text available
1. Forest landscape restoration (FLR) has gained momentum globally and guidance is needed to identify those species, sites and planting methods that increase restoration success. Incorporating native Non-Timber Forest Product (NTFP) species in FLR approaches provides an opportunity to simultaneously deliver ecological and economic benefits. The Bra...
Article
Full-text available
Agroforestry systems with a range of native and often neglected and underutilized tree species (NUS) are increasingly recognized for their potential role in restoration, simultaneously providing ecological and livelihood benefits. Successful adoption of these systems requires knowledge about beneficial species, system-level potential profitability,...
Article
Full-text available
Ecosystem services of Amazonian forests are disproportionally produced by a limited set of hyperdominant tree species. Yet, the spatial variation in the delivery of ecosystem services by individual hyperdominant species across their distribution ranges and corresponding environmental gradients are poorly understood. Here we use the concept of habit...
Thesis
Full-text available
• Non-timber forest products offer a critical opportunity for supporting sustainable development of rural communities and conservation of natural ecosystems. The Brazil nut (Bertholletia excelsa) is arguably the most prominent NFTP from the Neo-tropics, as a globallytraded product from a hyperdominant carbon-rich tree and cornerstone species for ra...
Article
Full-text available
The Brazil nut is a highly valuable non-timber forest product from a wild, hyper-dominant, emergent tree species that is increasingly vulnerable and exposed to habitat degradation. We provide evidence for how Brazil nut genetic resources are negatively affected by forest degradation and discuss the consequences of this for reproductive success. To...
Article
Full-text available
Forest landscape restoration (FLR) is globally important to mitigate a wide range of social and environmental problems driven by landscape degradation and deforestation. Despite widespread recognition of the urgent need to restore biodiversity and ecological functioning across many forest landscapes, there is an apparent mismatch between political...
Data
Allometric model. Details on methods of the construction of an allometric model for estimation of biomass per plant part of seedlings of 6 months of age. (DOCX)
Data
Iterative growth model. Details on methods of the construction and adaptation of an iterative growth model for estimation of daily individual seedling NAR, flam and γ. (DOCX)
Preprint
Full-text available
Defoliation is a ubiquitous stressor that can strongly limit plant performance. Tolerance to defoliation is often associated with compensatory growth. Genetic variation in tolerance and compensatory growth responses, in turn, play an important role in the evolutionary adaptation of plants to changing disturbance regimes but this issue has been poor...
Article
Full-text available
1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth differences have so far been documented for canopy tree...
Data
1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth differences have so far been documented for canopy tree...
Data
1. Persistent variation in growth rate between individual plants can have strong effects on population dynamics as fast growers reach the reproductive size at an earlier age and thus potentially contribute more to population growth than slow growers. In tropical forests, such persistent growth differences have so far been documented for canopy tree...

Network

Cited By

Projects

Projects (4)
Project
- In this study, we aimed to explore the role of genetic diversity in the success of early tree-planting stages as well as adult tree productivity. To this end, we made the following predictions: - Early stages of Brazil nut performance (germination, survival and growth of planted individuals) are positively related to their genetic diversity, which is known to be lower when seeds were obtained from degraded forest (Chiriboga‐Arroyo et al., 2020) - Fruit production of adult trees is positively related to their individual genetic diversity. We discuss the implications of these results for the resilient management of populations of this non-model tropical tree species within the context of tree genomics but also with respect to its high ecological and socio-economic value in rural areas of the Amazon basin
Project
In collaboration with the project PRODIGY, I am analyzing the extent to which increased implementation of agroforests could contribute to preventing, delaying or reversing strong changes in regional climate and associated changes in agricultural production in the tri-national MAP region in south-west Amazonia