The vulnerability of tropical peatlands to oil and gas exploration and extraction

Funding: Leverhulme Trust (Grant Number(s): RPG-2018-306); UK Natural Environment Research Council (Grant Number(s): NE/R000751/1, NE/R016860/1, NE/V018760/1); Scottish Research Council/University of St Andrews.Tropical peatlands store globally significant quantities of carbon and are ecologically and culturally important, but little is known about their vulnerability to oil and gas exploration and extraction. Here, we analyse the exposure of tropical peatlands to the activities of the petroleum industry and review what is known about the sensitivity of peatlands to these activities. We find that 8.3% (107,000 km2) of the total area of tropical peatlands overlaps with a 30-km buffer area around oil and gas infrastructure. Major areas of overlap include the Sumatra Basin (Indonesia), the Niger Delta (Nigeria) and the Putumayo-Oriente-Marañón Basin (Peru/Ecuador/Colombia). Documented environmental impacts include deforestation and habitat loss associated with the exploration and development of oil fields, and contamination from spills of oil and produced water (well brine). Peatlands, and the ecosystem services they provide, are sensitive to these impacts due to unique aspects of their ecology and hydrology, the easy spread of contamination by flowing water, the long-term storage of contaminants in peat, and the slow degradation of oil under anoxic, waterlogged conditions. Given the potential negative consequences for human health, resource security, biodiversity, and carbon storage, we propose a research agenda to provide an improved evidence base to support effective governance.Publisher PDFPeer reviewe

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Phylogeography and phylogenetic diversity of Amazon tree species and communities

The Amazon rain forest is the most diverse ecosystem on Earth, harbouring more than ten thousand tree species. In this project, I used ecological and molecular information to explore how ecological factors and historical events have determined the species distributions and population genetic structure of tree species and the phylogenetic diversity of tree communities in the Amazon rain forest. Chapter 2 indicates that seasonally dry vegetation in northern South America represents a barrier to migration for Ficus insipida (Moraceae) and other wet-adapted Amazonian tree species as they have different plastid haplotypes restricted to Mesoamerica and Amazonia. Conversely, the ability of some pioneer species to survive seasonal drought may explain the weakly differentiated phylogeographic structure within these species, with some haplotypes occurring on both sides of this barrier. Chapter 3 explores whether patterns of population genetic structure in five widespread western Amazonian tree species are consistent with historical explanations. My results show that the genetic patterns among species are not entirely congruent suggesting that tropical rain forest species respond differently to long-term geological and climatic changes. Despite this, some tentative generalisations emerge, notably high genetic diversity and a strong geographic structure for plastid sequences suggesting long-term population stability across western Amazonia, and recent population expansions in the south-western Amazon. Chapter 4 uses 283 floristic inventories from the RAINFOR plot network to explore patterns of phylogenetic diversity across Amazonia. This study reveals that the species-rich communities of central Amazonia are dominated by phylogenetic close relatives compared to the equally species-rich communities of the north-west that tend to contain more distantly related species. Across Amazonia, an east-west gradient of the abundance of early divergent angiosperm clades was found, with the greatest percentage of tree species of Magnoliids and Monocots in the west. As these early diverging clades are also characteristic of pre-montane habitats, these results suggest that migration events from cooler environments at different geological times has played an important role in the assemblage of the most phylogenetically diverse communities in Amazonia. The findings from these three chapters corroborate the notion that both ecological factors and historical events have been important in determining species distributions and the phylogenetic diversity of tropical tree communities in Amazonia. Regional differences in genetic structure among populations, and phylogenetic diversity among communities, should both be taken into account in forest conservation planning and management

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Curiosity Conversation - Living by the Land

In this episode, Dr Euridice Honorio speaks with Eilidh and Matt about making sustainable choices and having an impact, especially around peatland areas

Curiosity Conversation - Living by the Land

In this episode, Dr Euridice Honorio speaks with Eilidh and Matt about making sustainable choices and having an impact, especially around peatland areas