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9-10 June 2018
Vegetation surveys and Pollution assessments at the Green Lung and Bang Pu
Aim – Comparing vegetation across two different areas of the Green Lung and completing a pollution survey at Bang Pu mangrove
The weekend started with observing land and river usage at Ban Krachao, (the Green Lung) to understand the sort of human impacts that might be present and might influence the vegetation types present on the island and also that might affect the mangroves found at the mouth of the Chao Phraya.
Observations- land use in the area varied across both riverbanks. The riverbanks of the green lung were mostly being used for residential and agricultural purposes, while on the opposite bank the uses were more industrial with many factories and warehouses. Many large cargo barges navigated the river back and forth to the coast
Investigation 1- Vegetation survey site 1
Students completed a survey of vegetation found within one of the more urbanised areas of the island, considering the numbers and species of vegetation, the structure of the layers and planting layout.
Observations- Students noted a large number of fruiting trees including papaya, banana and pomegranate, as well as a large number or brightly coloured flowering plants such as hibiscus and bird of paradise plants. There were many low lying shrubs and plants as well as some taller trees such as tamarind. There was a low level canopy and lots of climbing plants and vines growing between the understory and canopy level. Many plants were planted in regimented ‘plots’
Community Investigation- Visiting the local market showed that although some vendors were using sustainable packaging such as banana leaves, bamboo cups and recycled paper, many relied on plastic containers, polystyrene tray and plastic bags, many of which were observed floating in the river on which the market sits.
Vegetation survey site 2
This time taking place within a park setting observations here indicated that there were many less flowering plants and fruiting trees than the students had expected and many taller and older tree species such as the flame tree, than had been recorded at the previous site. Within the park the trees and plants were growing in a less regimented fashion, with a denser understory with a mixture of small trees, palms and bushes and the park lacked the bright flowering plants.
Survey results comparison - The students results led them to suggest that the in the areas inhabited by people, the vegetation had most likely been selected and planted to provide food for people living in the area and also for the wellbeing effects of enjoying flowering plants. Many of the trees were quite young and there was a low canopy with many climbing vines, suggesting that many of the areas were newly planted and not yet fully established. Within the park the sporadically growing trees suggested many were probably wild sown rather than planted by people. Few of the species had fruit or bright flowers indicating thy may be naturally occurring rather than having been selected for providing food or bright colours.
Conclusion- After completing the surveys students began to understand the human impacts on vegetation structures and considering the different reason humans may influence where and how vegetation grows- eg food crops being favoured over nonfood plants in residential areas or brightly coloured or scented plants being favoured for their well-being affects. Students also considered methods of seed dispersal and the effects these can have on patterns of plant growth and again how these can be influenced by humans, to create gardens or vegetable plots for example.
Phase 2 Investigating pollution within the mangroves.
After an initial tour of the mangrove boardwalks to learn more about the unique habitat and species that live there, a whole site survey was carried out with students mapping the locations of any pollution, and highlighting the types of pollution found. Students also carried out water testing from 2 different areas of the site to investigate water conditions and any pollutants present.
Results- The most common waste items littering the site were plastic bottles and containers, polystyrene packaging, glass bottles, wood and bamboo, items which we had seen many of in the river upstream at the green lung and many of which can be recycled or reused if disposed of in a suitable manor. Water testing revealed nitrates and phosphates were found to be present above the normal expected levels and water temperatures were high between 29 and 31 degrees centigrade. Dissolved oxygen levels were good and water was found to be towards the more alkaline end of the pH scale.
Conclusion- After completing surveys and water testing students spent time on mangrove restoration- starting with mangrove replanting of the native red mangrove species and followed by a litter pick where students cleared over 20 bin bags of rubbish from the mangroves. Students were shocked to see the amount and types of litter that washed into the mangroves of Bang Pu, speculating most of it originated in Bangkok and flowed down the Chao Phraya River. The group discussed the negative impacts that pollution- both chemical and physical can have on endangered ecosystem and the species that live there. After the experience the students vowed to try and be more sustainable consumers, reducing their use of single use plastics and trying to use more sustainable containers such as fabric bags and reusable drinking cups with bamboo or metal reusable straws and to ensure they were disposing of waste responsibly, recycling wherever they can, in an effort to reduce pollution entering the rivers and mangrove ecosystems.