The study titled “Tracing the Possible Root Causes for Fleeing Flamingos in Kenya’s Lake Nakuru National Park” conducted by Nehemiah Kiprutto and colleagues investigates the factors leading to the significant decline in flamingo populations at Lake Nakuru. Using a fishbone diagram to systematically analyze the problem, the researchers identified multiple root causes of this decline, primarily focusing on human activities and environmental changes around the lake’s catchment area. Here is a concise summary of the study’s key findings:
Key Findings
- Deforestation in the Mau Forest Complex
- The research highlights that deforestation in the Mau Forest Complex, which serves as a critical water catchment area for Lake Nakuru, is the primary cause of reduced water inflow into the lake. Over 46% of the forest has been lost due to illegal logging, agricultural expansion, and settlement since it was degazetted in 1994.
- This deforestation has led to soil erosion, siltation, and drying up of the rivers feeding the lake, which has significantly lowered the lake’s water volume.
- Declining Water Volume
- The lake has lost approximately half of its water over the past two decades. Reduced inflows from the three main tributaries (Njoro, Makalia, and Nderit rivers), combined with siltation, have decreased the lake’s water levels, directly impacting the lake’s ecosystem and the flamingo population.
- Pollution and Toxins
- Industrial discharges, agricultural runoff, and untreated sewage have been identified as significant contributors to water pollution in the lake. This pollution has been linked to the increasing presence of toxic cyanobacteria, which are harmful to flamingos, contributing to their deaths and migration to other Rift Valley lakes.
- Previous studies cited in the research also found high levels of heavy metals and agricultural chemicals in the lake, further disrupting the flamingos’ primary food source—blue-green algae.
- Competition for Food
- The introduction of tilapia into the lake in the 1950s has contributed to food shortages for flamingos, as tilapia compete for the same blue-green algae that flamingos depend on. This competition, combined with pollution, has caused a drastic decline in flamingo food availability.
- Tourism and Local Poverty
- The study points out that local communities in Nakuru receive negligible economic benefits from tourism, despite the fact that the lake attracts over 200,000 tourists annually. As a result, poverty drives unsustainable practices such as deforestation and over-exploitation of forest resources, further exacerbating environmental degradation.
- The lack of community engagement in tourism and conservation has led to a disconnect, where the local population sees little reason to protect resources that primarily benefit outsiders.
- Climate Change and Global Warming
- Rising temperatures due to climate change have increased evaporation rates at the lake, contributing to the reduction of water levels and altering the lake’s temperature, which impacts the organisms that flamingos feed on.
- The erratic weather patterns, droughts, and unpredictable rainfall also compound the problems of water scarcity and ecosystem imbalance.
Recommendations
- Integrated Catchment Management
- The study recommends adopting an integrated catchment management approach that involves all stakeholders—local communities, government, and conservation groups—in managing the resources of Lake Nakuru. This includes reforestation efforts in the Mau Forest and sustainable agricultural practices to prevent further siltation and water depletion.
- Reform Forest Legislation
- The government should reform forest protection laws to better involve local communities in managing the forests and ensuring the sustainable use of resources. This could include empowering communities through eco-friendly tourism ventures that provide direct benefits, encouraging them to participate in conservation efforts.
- Address Pollution
- Urgent action is needed to control industrial discharge, agricultural runoff, and sewage treatment around Lake Nakuru. Improved waste management systems and stricter environmental regulations are crucial for restoring water quality and ensuring the flamingos’ primary food source, blue-green algae, is preserved.
- Further Research
- The study advocates for further research into the impacts of climate change on Lake Nakuru’s ecosystem and the long-term effects of deforestation on the flamingo population. Understanding these dynamics will help in making more informed decisions regarding the park’s conservation.
More Research on Lake Nakuru Flamingo Declining Population
1. Key Ecological Context
Lake Nakuru is an alkaline soda lake located within the Great Rift Valley, Kenya. Its ecosystem is fragile, with its alkaline waters (pH 10.5) supporting cyanobacteria, specifically Arthospira fusiformis and Spirulina platensis, which are the primary food sources for the lesser flamingos. Flamingos thrive on this algae-rich habitat, but this ecosystem is highly susceptible to climatic changes and human activities. Unlike other lakes, Lake Nakuru has no outflow, with water loss occurring solely through evaporation. This makes it especially vulnerable to pollution and fluctuations in water levels.
2. Flamingo Mortality and Behavioral Changes
- Mortality Events: Tens of thousands of flamingos have died during drought periods, such as in 1993, and during El Niño in 1997, which diluted the lake’s salinity and decreased food availability. The year 2000 saw the death of 40,000 flamingos, with symptoms such as disorientation and immobility observed in the birds. Many flamingos that left the lake during these events never returned.
- Pollution: Heavy metals such as lead, mercury, and arsenic have been found in the tissue of flamingos from both Lake Nakuru and nearby Lake Bogoria. These pollutants originate from industrial effluents and pesticides used in the surrounding agricultural lands. Organochlorine pesticides, specifically, have been hypothesized to accumulate in cyanobacteria, which are then consumed by the flamingos, leading to bioaccumulation of toxins in their bodies.
- Altered Migratory Patterns: Due to environmental degradation, flamingos have changed their migratory patterns, often moving to other lakes such as Lake Bogoria, as conditions at Lake Nakuru worsen.
3. Hypothesized Causes of Flamingo Deaths
The study outlines several hypotheses as potential causes of flamingo deaths at Lake Nakuru:
- Pollution and Toxicity: Pollutants enter the lake via runoff from agricultural fields, industrial effluents, and untreated sewage from the city of Nakuru. These toxic substances, particularly organochlorine pesticides, are suspected to accumulate in cyanobacteria, which are then consumed by flamingos, leading to endocrine disruption, disease, and death.
- Water Depletion and Drought: Decreasing water volumes due to drought and settlement activities in the catchment area have changed the lake’s salinity. Reduced water inflows and evaporation concentrate pollutants, and changes in salinity affect the types of phytoplankton present, reducing food availability for flamingos.
- Climate Change: Rising temperatures have increased evaporation rates, leading to reduced water levels and altering the chemical balance of the lake. The lake’s shrinking size concentrates pollutants and further disrupts the flamingos’ food chain.
4. Evidence and Observations
- Heavy Metals: Numerous studies, including those by Kairu (1994) and Wanjiru (2001), confirmed the presence of heavy metals in both flamingo tissue and the waters of Lake Nakuru. These metals are thought to come from industrial plants and sewage treatment facilities.
- Pollution Sources: The growth of Nakuru town, now with a population of over 400,000, has outpaced the capacity of local waste treatment facilities, leading to stormwater runoff carrying pollutants into the lake. During rainy seasons, the concentration of pesticide residues and heavy metals in the lake increases, contributing to higher flamingo mortality.
- Cyanobacteria and Pesticides: It has been suggested that cyanobacteria may absorb organochlorine pesticides, which flamingos ingest as they feed. This bioaccumulation of toxins can lead to chronic health issues and eventually death.
5. Potential Analysis Methods
The study suggests several analytical methods to test the hypotheses regarding flamingo deaths, focusing on:
- Pesticides: Detection methods for organochlorine pesticides in water and flamingo tissues.
- Heavy Metals: Analysis of sediment and water samples to measure heavy metal levels, using EPA method 525.2.
- Salinity and Water Composition: Testing the chemical constituents of the lake to assess changes in salinity that may impact flamingo food sources.
Conclusion
The decline in flamingo populations at Lake Nakuru is largely driven by human activities—particularly deforestation, pollution, and poor land management—combined with the broader impacts of climate change. The research emphasizes the need for a collaborative, sustainable development approach that involves local communities in conservation and addresses the root causes of environmental degradation to preserve Lake Nakuru’s unique ecosystem and its iconic flamingos.