AP Environmental Science 8.4 - Human Impacts on Wetlands

Summary

In this video, Mr. Smeeds takes us through the multifaceted issue of human impacts on wetlands and mangroves, essential ecosystems that provide numerous environmental services. Wetlands, characterized by their submerged soils and emergent vegetation, offer significant ecosystem services, including habitat provision, water filtration, groundwater recharge, and carbon sequestration. However, these ecosystems face significant threats from human actions such as pollution, development, and water diversion. Similarly, mangroves, which offer coastal protection and economic benefits, are at risk due to logging, aquaculture, and pollution. The video also explores potential solutions and management practices to mitigate these threats and protect these crucial ecosystems.

Highlights

• Wetlands are vital for biodiversity, offering habitat and protection but face threats from human pollution and development. 🌿
• Emergent plants in wetlands have unique adaptations to thrive in water-rich environments. 🌱
• Mangrove ecosystems protect coastlines and offer economic and ecological services but are at risk from human activities. 🌊
• Pollution from various sources can degrade wetland quality, impacting water and plant health. 🏭
• Solutions like cover crops and riparian buffers help in reducing agricultural runoff and pollution in waterways. 🌾

Key Takeaways

• Wetlands offer invaluable ecosystem services but are threatened by human activities such as pollution and development. 🌿
• Emergent vegetation in wetlands is specially adapted to water-logged conditions, supporting diverse habitats. 🐾
• Mangroves provide coastal protection and support biodiversity, offering economic and climate regulation benefits. 🌊
• Human activities like logging and aquaculture are detrimental to wetland and mangrove ecosystems. 🚜
• Finding sustainable solutions, such as riparian buffers and sewage management, can mitigate pollution impacts. 💧

Overview

Wetlands, home to unique emergent plants, are crucial ecosystems that support biodiversity and offer numerous environmental services. They help in water filtration, carbon storage, and groundwater recharge, benefiting agriculture and climate. However, these ecosystems face significant threats from pollution, development, and water diversion, which can lead to habitat loss and degradation of these critical resources.

Mangroves, on the other hand, play a significant role in coastal protection and are economically valuable due to their biodiversity and ecosystem services. Despite their advantages, mangroves are threatened by logging, deforestation, and coastal development. The rich resources they provide, like food and fuel, are often unsustainably harvested, putting them at risk of destruction.

To combat these threats, sustainable solutions are essential. Implementing methods like riparian buffers, cover crops, and improved sewage management can significantly reduce the impact of pollutants. These strategies not only protect wetlands and mangroves but also help in maintaining the ecological balance crucial for supporting the livelihood of communities relying on these ecosystems.

Chapters

• 00:00 - 00:30: Introduction to Human Impacts on Wetlands The introductory chapter on human impacts on wetlands delves into how human actions affect mangroves and wetlands. It outlines the objectives for the discussion, emphasizing the ability to describe the impacts of human activities on these critical ecosystems. The key takeaway includes understanding the basic definition of wetlands, characterized by their water-submerged soil for varying periods, and the presence of certain ecological features.
• 00:30 - 01:00: Importance of Wetlands The chapter titled 'Importance of Wetlands' discusses the role and adaptation of emergent plants in wetland ecosystems. These plants have their roots anchored in the soil while parts extend out of the water, enabling them to survive. The chapter explains the significance of these adaptations, as most plants cannot survive with submerged roots due to lack of oxygen. This ties back to agricultural concepts where crops may suffer from over-saturated soil conditions leading to oxygen deprivation for the roots.
• 01:00 - 02:30: Ecosystem Services Provided by Wetlands This chapter discusses the importance of wetlands and the ecosystem services they provide. Wetlands are characterized by water presence and emergent vegetation, with plants adapted to these conditions. They offer a range of ecosystem services, including provisioning services, which involve creating habitats for various animals and plants. Understanding and protecting wetlands is vital due to the significant benefits they offer.
• 02:30 - 06:00: Threats to Wetlands from Human Activities Wetlands offer both direct and indirect benefits. They serve as sources of food and raw materials, while also delivering critical ecosystem services. One of their key roles is in regulating ecosystems, particularly through groundwater recharge. Wetlands allow groundwater to enter the soil gradually, which can be later used for agricultural or drinking purposes, and in a cleaner form thanks to purification by plant roots. These roots trap and sometimes metabolize pollutants, preventing them from contaminating groundwater. Additionally, wetlands contribute to carbon sequestration, storing significant amounts of CO2.
• 06:00 - 09:30: Benefits and Threats to Mangrove Ecosystems The chapter discusses the dual role of mangrove ecosystems in environmental conservation, highlighting their benefits and existing threats. Mangroves play a crucial role in mitigating climate change by absorbing CO2 and converting it into bark and other forms, thus preventing atmospheric pollution. They also provide essential ecosystem services such as water filtration, where their roots trap pollutants and prevent them from contaminating groundwater. Additionally, mangroves support biodiversity as they create habitats for pollinators and various other wetland organisms.
• 09:30 - 13:00: Solutions to Pollutants Entering Water Bodies The chapter titled 'Solutions to Pollutants Entering Water Bodies' highlights the crucial role of pollinators such as bees, dragonflies, and butterflies in agriculture by aiding crop pollination and thereby benefiting the economy. It also discusses nutrient recycling, where dead organic matter is broken down and nutrients are returned to the soil. The accumulation of peat at the bottom of water bodies is noted, emphasizing its potential use as a fuel source in developing nations and its composition as rich organic matter. The chapter also covers natural pest control mechanisms, where certain organisms feed on pests, helping manage pest populations naturally.

AP Environmental Science 8.4 - Human Impacts on Wetlands Transcription

• 00:00 - 00:30 hey everybody it's mr smeeds and welcome to apes video notes for topic 8.4 which will cover human disturbances to mangroves and two wetlands our objective for the day is to be able to describe the human activities that have impacts on wetlands and on mangroves and the skill that we'll practice at the end of today's video will involve describing a solution to an environmental problem so wetlands are going to be areas where the soil is submerged in water for all or part of the year and another important thing to consider is that they have what are called
• 00:30 - 01:00 emergent plants or emergent vegetation and that's where we can see here in the diagram that the plants are going to have their roots anchored in the soil but part of the plant extends up and out of the water these plants are also going to be adapted to living in these conditions so most plants cannot survive with their roots totally submerged in water they wouldn't be able to get the oxygen they need remember back to our agricultural unit that crops can actually get their roots drowned they can have the oxygen they need basically pushed out of the soil by having too
• 01:00 - 01:30 much water in it but emergent vegetation and the plants that live in these ecosystems these wetland habitats are going to be adapted for that and so why are wetlands so important why does why is it important to understand the impacts we have on them and to protect them well they have a lot of ecosystem services and so like we mentioned at the beginning with the estuary habitats even freshwater wetlands are going to offer a huge host of ecosystem services so we have provisioning ecosystem services that would be creating habitats for animals and plants that we
• 01:30 - 02:00 utilize as food or as raw materials for things they're also going to provide a regulating ecosystem service so that's going to be groundwater recharge they slowly allow groundwater to seep into the soil we can use that water later for agriculture or for drinking and it's going to be cleaner it's going to be filtered by the roots of these plants they're basically going to trap pollutants in many cases they can actually metabolize the pollutants or just hang on to them so they can't go into the ground water they're also going to sequester carbon dioxide so they'll store co2
• 02:00 - 02:30 so the woody plants especially will take that co2 in and turn it into bark or in other structures and that prevents it from being in the atmosphere so it helps mitigate climate change we also have supporting ecosystem services so this would be the water filtration i mentioned earlier where the roots can really trap pollutants and prevent them from recharging or entering the groundwater that's being recharged by runoff we also have pollinator habitats and so many of the flowers or the other organisms in a wetland are habitats for
• 02:30 - 03:00 pollinators like bees or dragonflies or butterflies that are going to go and pollinate our agricultural crops that's a huge benefit to farmers into that sector of the economy it's also going to help with nutrient recycling so it's going to take dead organic matter break it down return those nutrients to the soil we can see here that there's peat building up on the bottom i remember that peak can be utilized as a fuel source in developing nations and it's also just going to be really rich organic matter and then we even have pest control so a lot of organisms that eat pests
• 03:00 - 03:30 think of spiders or frogs they are going to thrive in these wetland habitats and so they can help prevent the spread of disease and prevent damage to crops due to their pest control you know services that they provide and then finally we have cultural ecosystem services so remember that would be things like tourism dollars that are flowing into an area because people want to come visit want to pay for fishing licenses or boating fees but also just the educational research that's done that could produce new medications or it could just produce you know degrees for students that are
• 03:30 - 04:00 seeking them and help them earn more wages in the future due to the knowledge they gain from the research now we'll take a look at some threats to wetlands as a result of human activities and so we have already covered in depth the nutrient pollution threat but remember that there are other pollutants such as sediment motor oil that drips down from our cars onto pavement and then washes off into our storm drains into our bodies of water pesticides from agricultural fields then we can also have endocrine disruptors so remember these
• 04:00 - 04:30 are medical compounds that pass through the human body or are improperly flushed down the toilet then we have development so development can be a really big threat to wetlands wetlands can actually be filled in or drained just in order to create stable land that we can develop in homes parking lots stores or agricultural land and so that can just completely remove them you know and that costs animals habitats it removes all of those ecosystem services that we just talked about so that's a really big threat another
• 04:30 - 05:00 threat that doesn't remove them entirely right away but can lead to their decline is water diversion so humans divert water from streams and rivers for a variety of reasons and what that does is basically decreases the water level and eventually the wetland habitats downstream so we have a great example here in the everglades if you look at the diagram on the left you can see the historical range of the wetlands that surround the everglade ecosystem you can see
• 05:00 - 05:30 how far that water floods uh when the river is in its highest you know velocity or its highest flow so that's going to be a habitat for tons and tons of organisms it's going to provide a lot of ecosystem services but you can see on the right side all of those little red lines are channels where water is being diverted for all of these different purposes it could be diverted for agriculture so farmers could be using it could be diverted for drinking water so as florida's population grows they may be using that water to just supply municipalities
• 05:30 - 06:00 they can also be using it for flood control so they may install dams to prevent downstream flooding from occurring as urbanization extends as more homes are built for more people and so just a huge variety of purposes that are reasons that people may divert water from upstream and again that decreases the amount of water downstream and eventually leads to these watersheds you know becoming lowered or eventually drying up completely also we could have hydroelectric power
• 06:00 - 06:30 so that would be one other instance where a dam could be used to block the river and that's going to really dramatically decrease not only the flow of water downstream but also the flow of nutrients remember that sediment and the nutrients that are vital for the plants living in those wetlands would be caught behind the dam they would build up and so that would drastically alter the soil fertility of those wetland habitats downstream another impact we want to think about is overfishing if we overfish wetlands we disrupt the food system there or the
• 06:30 - 07:00 food web i should say so we may disrupt predator play predator prey imbalances when we're overfishing and so that can really disrupt the stability of that ecosystem and finally we'll wrap up today by taking a look at the benefits of and the threats to mangrove ecosystems so i just have to say sometimes when i'm making these videos and looking for diagrams i just find something that's almost too good to believe and so i want to say thank you to the wwf the world wildlife foundation and the international union for the
• 07:00 - 07:30 conservation of nature it's like someone did my job for me here this diagram is just perfect and so i want to start off with the mangrove ecosystem services so it's estimated that mangrove ecosystem services provide about 800 billion dollars worth of value so that's an incredibly value valuable habitat to protect and so where do those services come from well developing nations that could be a source of fuel they could use it for wood as long as it's sustainably harvested and still left there for future generations
• 07:30 - 08:00 but coastal protection is another huge advantage so mangroves are really effective at buffering storm water at protecting the human habitats behind them and they're estimated to be five times more effective than building a break wall or a sea wall or something like that and so these natural coastal buffers are just super super effective they're going to be really good at water filtration as well they're going to trap pollutants in their roots and recharge the soil with cleaner groundwater they're a huge tourist attraction so people are going
• 08:00 - 08:30 to come visit them they're going to be home to many different fish and shellfish shellfish species try that one five times fast so super valuable to the people that fish them and to the habitats that they stabilize and then climate regulation they're also very very effective at sequestering carbon dioxide and so when we take in all of these factors they have tremendous tremendous value and so what are the threats to them why are mangroves you know at risk here
• 08:30 - 09:00 so a lot of reasons but one would be logging and deforestation so we clear them oftentimes for development now developing nations may be used as a subsistence fuel but in developed nations it's primarily because beachfront property is so valuable and so we just cut them down to put up condos or resorts so that's the coastal development point you can see here it's just really really valuable real estate for people and so we put buildings there and kind of ignore the ecosystem services that they
• 09:00 - 09:30 provide aquaculture is another reason and so that would actually be fishing of or the farming i should say a fish or shellfish oftentimes it's shrimp there's a huge demand for that and so we cut down the mangroves and basically put these nuts in the water where we grow all sorts of aquatic species to be done for agriculture so rice paddies remember rice is a crop that grows really well in flooded soils and so it's prime area to put up a rice paddy as well and finally we have pollution so remember
• 09:30 - 10:00 that all of the pollutants in a watershed that drain into a central body of water are going to end up emptying into the ocean at some point and that's where they could come to rest in these mangrove ecosystems if they're sediments they may kind of clog the root systems of these mangroves prevent prevent them from getting the oxygen they need they could actually be solutions that are toxic to the mangroves actually killing their roots so if there's heavy heavy metal pollution that's going to be really problematic so all of these threats to mangroves are reasons that we should consider
• 10:00 - 10:30 protecting them and trying to keep this really really valuable habitat intact now we'll take a look at some solutions to these pollutants entering bodies of water and so if we take a look at c and a in this diagram these are two methods that could be used to reduce nutrient inputs from agriculture so cover crops are a great strategy that you hopefully remember from our sustainable farming unit or our sustainable farming topic back in unit 5. but a cover crop is going to be basically using some plant in between the main
• 10:30 - 11:00 crops that you're harvesting just to kind of hold the soil in place anchor it and keep those sediments and the fertilizer on your field from running off into bodies of water so you can see if you're continually planting a cover crop each season it's just going to do a phenomenal job of preventing runoff from entering these bodies of water it traps the runoff it lets it infiltrate back into the soil it uses up some of those excess nitrates and so a really effective solution you can also try to adopt better animal manure management practices so this could involve a manure lagoon
• 11:00 - 11:30 that's lined better that has higher banks or berms to kind of contain that manure could be a system that even drains it more frequently and turns it into fertilizer pellets and then if we look at b another really good generalized strategy is riparian buffers riparian habitats or riparian areas refer to the areas alongside a body of water such as a river and so when you plant vegetation in riparian habitats what you're doing is adding in basically a giant sponge or a giant filter
• 11:30 - 12:00 so that the runoff entering that body of water has gone through all of this vegetation first the roots are going to absorb a lot of the water depending on what kind of plants you use the roots may be really effective at even trapping pollutants in their root structures and then metabolizing them or just preventing them from making it into that body of water and so riparian buffers are a really valuable strategy for kind of reducing these pollutants entering bodies of water if we look at letter d and at letter f these are both going to target human sewage
• 12:00 - 12:30 and so we can have septic tank upgrades a septic tank is where you just have a tank in your backyard that collects your waste and depending on how we optimize the drain field to more slowly you know drain the sewage out it can just allow that to be filtered more naturally by the ground and prevent it from overflowing and contaminating nearby surface waters and then we can also have biological waste removal so that's where there are microbes that are going to be eating a lot of the waste and trying to utilize a lot of those nutrients to prevent those from
• 12:30 - 13:00 being released into the river and so just a ton of different options for trying to reduce nutrient and sediment inputs into bodies of water so for practice frq 8.4 today i want you to describe how one specific human activity can lead to an increase in phosphorus levels in an estuary ecosystem then i want you to try to describe one step that could be taken to reduce the phosphorus inputs from the activity you described above