This study seeks to understand the hydrological interactions and habitat diversity of the Napo River, a major Amazon tributary that drains 100,000 km2 of Andean forest lands. It is a sparsely inhabited region of exceptional biodiversity. The lowland Napo River (860 km) has been identified by development groups as a key link for a continent-wide navigation network that would connect Pacific ports, Andean highways, and the mainstem Amazon. This proposed conversion of the Napo River into an industrial waterway would require engineering to increase and stabilize its depth, which could lead to significant alterations to the hydrology of adjacent floodplains. There has been little ecological work on the hydrology of the river and its impact on floodplains that can underpin a scientific assessment, although it is known that local inhabitants depend on these resources and on ecological processes dictated by the flood pulse of the river. This study will identify the temporal and spatial variability of water levels in the region, assess the extent and diversity of floodplains and wetlands, and determine how alteration of the water-level regime of the river may affect biodiversity and ecosystem services associated with floodplains and wetlands of the Napo River system. Remote sensing techniques will be combined with data from 100s of deployed temperature sensors, water chemistry measurements, and applied in a hydrologic model.
The outcomes of this research will improve the current understanding of floodplain-river interactions, and as such, can contribute to the scientific basis upon which decisions about this large development project, as well as about biodiversity and related conservation targets, can be informed.
Dissertation Research: Hydrological Controls of riverine ecosystems of the Napo River (Amazon Basin): Implications for the Management and Conservation of Diversity (Jorge E. Celi, advised by Stephen K. Hamilton) Scientific understanding of neotropical floodplains comes mainly from work on large rivers (e.g. the Amazon mainstem) with predictable seasonal flooding regimes. Less studied rivers and floodplains such as those that lie along the Andean-Amazon interface are clearly distinct in their hydrology, and thus ecological roles of floodplain inundation likely differ in those ecosystems. Multiple and less predictable flooding events over the course of a typical wet season control inundation of floodplains, fish migration, plant growth, and associated human activities. Yet we are just starting to obtain a comprehensive description of the hydrology of these river systems and their vast fringing floodplains. This study seeks to understand the hydrological interactions and habitat diversity of the Napo River, a major Amazon tributary that drains 100,000 km2 of Andean forelands (a sparsely inhabited region of exceptional biodiversity), and a river that is envisioned as an industrial waterway in the future (see figure). The aims of this doctoral research are: 1) To identify the spatio-temporal variability of water levels in areas directly flooded by the Napo River, and indirectly flooded through river backwater effects that delay the drainage of local precipitation or runoff; 2) To assess the extent and diversity of floodplains and wetlands along the river corridor and their relation to river hydrology; and 3) To understand the role of and how alterations to river hydrology and geomorphology would impact river-floodplain hydrological connectivity and thereby affect the floodplain wetlands. Specific research objectives are: 1) To characterize the chemistry of waters during floodplain inundation to better understand water sources and flow paths; 2) To increase temporal coverage of hydrological data collection in the field; 3) To classify the aquatic environments of the Napo River corridor using remote sensing and lay the foundation for a hydrological model; and 4) To apply this understanding to assess the potential impacts of a proposed industrial waterway on its surrounding aquatic environments. So far we have addressed the first two objectives, and are currently working towards the achievement of the third. This DDIG grant allowed us to conduct intensive sampling campaigns during 2010 in which we assessed the water chemistry of remote headwaters of local swamps and floodplains, the Napo River from its confluence with the Amazon River to the foothills of the Andes, and environments likely inundated by the Napo River. These sampling trips follow several earlier trips funded by other sources. Besides increasing our knowledge of the spatial variability of hydrological regimes of water bodies along the Napo River, this DDIG grant allowed us to obtain an additional year of hydrological records of these environments. Currently we are working with collaborators from the Woods Hole Research Center in Massachusetts to classify the aquatic environments of the Napo Basin using remote sensing techniques, and better assess the extent and diversity of flooded environments and their relation with the river. This is a particularly challenging environment for remote sensing of floodplains due to the nearly continuous cloud cover and the dense forest canopies, and therefore we have to use state-of-the-art techniques. Products of this assessment will be used to link to our hydrological data, provide recommendations to improve management of ecosystems and support conservation of biodiversity in the region. Through our field work several undergraduate students from Ecuadorian and Peruvian universities have been trained in these methods and helped collecting and processing water samples, as well as retrieving and deploying data loggers, among other things. One is conducting his undergraduate research at an Ecuadorean university in connection with our project. We have also taken had several students from the US as volunteers on field expeditions. The Napo floodplains are situated in one of the most diverse and remote regions of the world, but are also inhabited by indigenous communities who use them as farmlands or hunting grounds. During our field trips we have been able to interact with the locals, working closely with them in our project of the eco-hydrology of floodplains of the Napo River, and exchanging knowledge of the ecology and hydrology of these systems In addition to conversations with the locals we have presented results of our research in several scientific meetings in the US, Ecuador, Brazil and South Africa. We anticipate that this research will be pivotal in eventual decisions about development of an industrial waterway in the Napo River system, and contribute generally to the management and protection of the floodplain ecosystems on which local inhabitants depend. Additionally, it will advance our scientific understanding of an important kind of floodplain that is distinct from those which have been studied elsewhere.
