Conservation Issues: Questions & Answers
The following is a series of questions regarding important conservation issues facing the Madre de Dios region and answers based on insights gained from this study.
Conservation Q & A are also included in the project report.
Q: Can streams and rivers in the region be broadly classified for conservation purposes? If so, are certain characteristics more important than others with regard to conservation?
A: Yes on both counts.
Streams and rivers fall into three major biogeochemical categories with distinct microbial communities associated with each: (1) Clearwater [low levels of dissolved ions, dissolved organic carbon (DOC) and fine suspended solids (FSS)]; (2) Blackwater (low levels of ions and FSS but high levels of DOC); and (3) Whitewater (intermediate levels of DOC and high levels of ions and FSS). Conservation workers and others can distinguish among these three types visually and/or with simple field instruments.
Most small streams in the region have unusually low levels of nutrients but high levels of nitrogen as ammonia. This combination makes them vulnerable to oxygen depletion if exposed to excess nutrient loadings associated with human impact. Q. LaJoya, which can support virtually no living organisms and is dangerously toxic to humans, is a case in point.
Because of the low nutrients and low in-stream algal production caused by heavy shading, organic inputs from the riparian forests, such as leaves, wood, fruit, and seeds, dominate the food base, metabolism, and type and abundance of aquatic animals of most natural streams in the region. This means that maintaining the quality and quantity of riparian forest cover is a critical conservation priority throughout the region because it will help sustain the natural food web of the stream.
Nutrient uptake in natural forested streams was lower than in most undisturbed temperate streams, which suggests that the local streams are highly vulnerable to anthropogenic impacts from farm fertilizers and sewage inputs.
Q: Does the presence and abundance of “keystone” terrestrial animals (jaguars, monkeys, tapirs, macaws) accurately indicate the health of a watershed and its water resources and/or the degree of conservation success in the region?
A: Not always.
Watersheds containing an abundance of these keystone animals had streams indicating poor watershed health and/or on-going pollution. For example:
A stream (Q. TRC4) in the “pristine” Tambopata reserve was relatively clean and natural in most respects but had concentrations of one pesticide (Chloropyrifos) that were higher than Q. LaJoya, which is heavily polluted by contaminants from Puerto Maldonado.
A stream (Q. 2miradoricra) in the “pristine” Los Amigos Research Center and Conservation Concession was missing more than half its pollution-sensitive macroinvertebrate species. This indicates severe watershed disturbance, which could be either on-going or historical.
A stream (Q. ATI8) associated with the relatively “pristine” watershed near the ACEER-Inkaterra research facility had the second highest concentrations of the herbicide Atrazine measured in this study.
Since the forest food web depends on fresh water, it is likely that such water contaminants will accumulate in the terrestrial food web and place animals in the highest levels (e.g., keystone taxa) in jeopardy.
Q: Can the chemistry of the water give us a good indication of water quality and the type of human impacts in the watershed?
High ion and nutrient concentrations reflect high human impact in the region (case in point Q. LaJoya with the highest level of degradation and human impact as well as the highest ion and nutrient levels).
The ratios of ammonium nitrogen to total dissolved inorganic nitrogen (DIN) were higher at sites receiving sewage or manure inputs.
Stable nitrogen isotopes (δ15N) of nitrate and of fine particulate organic matter at most agricultural sites revealed enrichment due to both manure and sewage inputs.
Q: Are there specific aquatic animals whose presence and abundance indicate overall water/watershed health and potential for supporting viable populations of “keystone” terrestrial animals?
Streams containing four out of five of the following aquatic macroinvertebrate groups [crabs (Grapsidae), mayflies (Campylocia), stoneflies (Anacroneuria), and two caddisflies (Phylloicus, Triplectides)] always drained watersheds containing keystone terrestrial wildlife.
All study streams lacking three or more of the five aquatic groups were associated with highly impacted watersheds.
Q: Do water quality data that indicate watersheds incapable of supporting important wildlife also indicate high risk for human health?
A: We think so—but on a case-by-case basis.
Pesticides found in three streams at levels toxic to aquatic life are also carcinogenic to humans.
Fecal steroid ratios indicate that Q. LaJoya is contaminated with human waste, and the level of fecal steroids indicates that dangerous human pathogens are also likely to be present.
Some streams have high fecal steroid levels of non-human origin, but do not have dangerous levels of human pathogens (e.g., Q Abejitas, whose fecal steroid ratio indicates contamination from cattle).
Q: Can small pockets of human activity broadly jeopardize watershed health and hence on-going conservation activities?
A very small stream (Q. Infierno 3), which drained a small banana plantation, contained exceptionally high concentrations of the insecticide Chlorpyrifos and the fungicide Metalayxl, whose negative influences are transported downstream to other parts of the watershed.
Q: Does urbanization have a greater impact on water quality than agricultural development?
A: Both types of land use can severely impact a stream and often occur together.
An urban stream (Q. LaJoya) had elevated concentrations of every pesticide and PCB measured and a 100% loss of pollution-sensitive species, both of which indicate severe impact.
An agricultural stream (Q. INF3) had significant levels of insecticides and fungicides and an 80% loss of pollution-sensitive species, both of which indicate severe impact.
Stable nitrogen isotopes (δ15N) of nitrate and of fine particulate organic matter (FPOM) at most agricultural sites show the characteristic enrichment of both manure and sewage inputs.
Q: Should best management practices (BMPs) and policies, such as riparian forest buffers, which are common in temperate zones, be an integral part of watershed conservation efforts in neo-tropical watersheds?
A: Yes, the region needs policies to protect the riparian forest. However, because they can reduce but not eliminate loss of water quality and impairment of stream health, BMPs should not be used as an excuse to open conserved areas to development.
Site Q. Inf 5, whose watershed is partially deforested for cattle and row crop agriculture but has a wide and intact riparian forest along most of its length, had levels of pollution-sensitive taxa comparable to streams in conserved areas.
Site Q. Abejitas, whose watershed is largely deforested for cattle pasture, was able to retain 40% of its pollution-sensitive taxa and most of its ability to process nitrogen and phosphorus by keeping intact a 5-10 m riparian buffer.
Stable carbon isotope (δ13C) of fine particulate organic matter at Q. Km14 stream suggests that the partial removal of riparian forest along its length has already increased the relative abundance of algae in the stream’s food base relative to heavily shaded conserved streams — arguing for a policy to assure the long-term integrity of riparian forest in the region.
Q: Beyond global warming and impacts associated with increased UV radiation, are the watersheds and their human and wildlife populations at risk from exposure to toxic substances via aerial transport from industrial areas in South America (hence the need to conserve elsewhere in the region to assure success)?
A: This does not appear to be a problem based on our preliminary study.
PAHs, which are carcinogenic compounds from petroleum and combustion-generated soot, were uniformly low in all streams – and below all USEPA toxicity criteria for water quality. (For perspective, the Stroud Water Research Center recently studied 180 streams supplying drinking water to New York City and found 54 of them to have PAH levels exceeding the EPA water quality guidance values.)
Pesticides in some study streams throughout the region were undetectable (note: the study did not look for bioaccumulation of pesticides in the tissue of key wildlife.)
Q: Do conserved watersheds contain high levels of aquatic biodiversity? Is the biodiversity unique? And can it play a critical role in measuring water quality and watershed health in the region and in gauging conservation success?
A: Answer: Yes on all counts.
Biodiversity: Our 12 most extensively studied small streams contained 204 macroinvertebrate taxa (mostly genera). 50% of the macroinvertebrate taxa were found in only one or two streams – suggesting a high level of both alpha and beta species diversity. The microbial survey, which was the first of its kind in the Amazon basin, revealed distinct bacterial communities in the blackwater and clearwater streams of the conserved areas.
Uniqueness of Biodiversity: A significant percentage (> 30%) of macroinvertebrates collected appear to be new species to science. It appears that the microbial community specializing in processing ammonia (a common chemical in Andes Amazon streams) is not composed primarily of bacteria (as in non-tropical streams) but rather archaea (microbes that look like bacteria but are genetically distinct). The failure to detect bacteria in the ammonia processing community of the Andes Amazon streams, if confirmed, would represent an important and novel observation in the field of microbial stream ecology and would help increase the capacity of microbial ecologists working in the Moore Foundation’s marine program to understand what is emerging as an important issue.
Role in water quality monitoring: Macroinvertebrate groups sensitive to pollution in the Andes Amazon region (e.g., mayflies, stoneflies, caddisflies, hereafter the "EPT" group) appear to be similar, but not identical, to those that Stroud Water Research Center has worked with elsewhere in Latin America and the temperate zone. The extinction of pollution-sensitive macroinvertebrate taxa (EPT) from a stream ranged from 100% (highly polluted stream in the town of Puerto Maldonado) to 0% (a pristine stream in a conservation area), with most clean streams in the region losing less than 20% and most polluted streams losing more than 50%. The presence of five aquatic macroinvertebrate animal groups (Grapsidae, Campylocia , Anacroneuria, Phylloicus, Triplectides) consistently seems to indicate very high water quality.
Gauging conservation success: Loss of EPT taxa indicates that some streams (e.g., Q. 2miradorcicra) in conserved areas are not healthy and that their watersheds are either suffering from a legacy of previous impacts (and need pro-active restoration) or are in need of better and more widespread protection.
Q: Is the approach to water quality monitoring in the Andes Amazon region and the knowledge gained about its value to help plan, guide, and evaluate watershed conservation applicable elsewhere in the neo-tropics?
For example, on December 17, 2006, Bern Sweeney, director of the Stroud Water Research Center, arrived at “Nectandra,” a neo-tropical cloud forest preserve in Costa Rica (www.nectandra.org), just after having finished leading a weeklong series of “water quality monitoring” workshops as part of a Moore Foundation grant on Costa Rica’s Osa Peninsula. He had come to Nectandra at the request of its president, Alvaro Ugalde, and co-founders, David and Evelyn Lennette of San Francisco, CA. The Lennettes had purchased 99.9% of the Nectandra watershed in 1999 and had built and furnished a magnificent education/research center focused on conserving the virgin cloud forest and its jaguars, tapirs, and other native wildlife. Sweeney was asked to confirm the purity of the water of a stream called Quebrada Verde, in anticipation of using it for education purposes and for growing organic rice as a demonstration of sustainable agriculture. Employing the same macroinvertebrate sampling techniques he had taught his Moore Foundation students the week before, Sweeney determined almost immediately that the stream ecosystem was “dead” as a result of heavily polluted sediments and probably toxic chemicals in its water. These pollutants came from a tiny parcel of upstream land that the Lennettes did not own and which was used for growing ornamental plants for market. In subsequent visits that day to nearby streams whose watersheds were completely within Nectandra’s conserved area, Sweeney found water of consistently high quality. Thus, his quick and simple stream survey not only provided a direct measure of Nectandra’s conservation success, but it also revealed the immediate need to acquire the tiny piece of the watershed that was being poorly farmed and whose contaminated water and soil was washing into Q. Verde.