How To Be An Eco-Conscious Hiker and Protect Our Parks

I love the outdoors, and I love hiking. These are the two main reasons why I decided to dedicate my environmental pollution blog to talk about pollution issues in National Parks. After having gone through the different kinds of pollution that are prevalent in National Parks, what better way to conclude the blog, than to reflect on the ways in which you and I can be more eco-conscious as hikers? While National Parks around the globe are already centered on preservation, conservation, and habitat protection, visitors like us also have a part to play! Let’s take a look at some of the tips that we can follow before we hit the trails again!

Leave no trace 
As basic as this sounds, this rule can’t be emphasised enough, especially when hikers have the habit of bringing along plastic bottles with them, only to be discarded along the trails. Even though some of the discarded bottles may be picked up by cleaners, other passer-bys, or even park officials that may mail them back to you, those that have been left behind in more remote areas may end up in the soil and affect their health, or end up being getting washed into water bodies, as we have learnt in this blog post. Another problem is also overloaded waste disposal points in the trails, where rubbish bins that are located in harder to reach areas are not emptied as often as they should be, due to the limited access. Therefore, the best way to prevent this from happening is to simply have the habit of keeping any trash with you all the way until you exit the park. I am glad that some hiking organisers and adventure tour operators are encouraging their participants to practice the habit of keeping their own trash with them, by providing them with waste collection bags that they can use to store their trash, or pick up any along the way. This is based on my own personal experience of hiking in Kashmir with IndiaHikes, who provided us with eco-bags for the duration of our entire hike.

Me admiring the lush greenery and mountains in Kashmir. Notice that bright green bag that is attached to my backpack? That’s none other than the eco-bags provided by IndiaHikes!

A sign that I came across while hiking in Rinjani, Indonesia, reminding visitors to carry their trash with them

Being careful with water resources
If you’re going on a multi-day hike, chances are that you’ll need to refill your water along the way, as it is probably not the wisest or most feasible idea to carry all the water you require for the entire hike from day 1. Therefore, when coming across water sources such as rivers where you can replenish your refillable water bottles, you should always be responsible and take the necessary steps to avoid contaminating them. For instance, you should not wash your dishes/clothes in them, or use soaps/detergents that may cause chemical water pollution due to the oxygen-reducing substances in them, and contaminants such as phosphates that may result in eutrophication.

Keep your volume down
Yes, I get it. Being outdoors with friends can get pretty exciting, and our eager selves may get carried away and make lots of noise. Some of us may even start blasting music from phones or speakers to create a more vibrant atmosphere while hiking, and I have to admit, that I was guilty of such behaviour as well. However, having done some research on the effects of noise pollution in National Parks, I am more than convinced that we have to try our best to remain quiet and preserve the silence in these parks. Noise is a known psychological and physiological stressor, and anthropogenic noise does not only affect fellow hikers, but wildlife and plants too. Therefore, it is the responsibility of us visitors, to be more mindful of the environment and lower our voices when speaking in National Parks. Instead of listening to music, listen to the sounds of nature; the rush of the winds through treetops, the humming sounds of birds, the gurgle of streams. Breathe easy, relax and listen. Only then can we truly appreciate the subtle sounds of our parks!

Taking a minute to enjoy the sounds of nature while hiking in Taiwan

Orangutans need more than your well-meaning clicktivism

A sign for visitors to respect the homes of Orangutans and remain quiet in Borneo, Indonesia. Source: Darren Whiteside / Reuters


Stick to the marked out trails
Hikers are naturally an adventurous bunch, and some of us would not hesitate to venture off the beaten track and deviate from the marked trails. Besides compromising on your safety, there are also other reasons why we should not trample off path, such as the damaging effect it has on the environment, namely soil erosion. Besides the trampling of extensive vegetation, habitats and nesting grounds of animals may also be disturbed, thus disrupting ecosystems. Therefore, the best thing you can do to combat path erosion is to walk on the designated paths. I get that it can be quite tempting to cut off corners of a zigzag descent and take shortcuts instead, but do remember that the paths are there for a reason!

Opt for headlamps with red LED mode
White light can be blinding and painful to both humans and animals, especially in naturally dark environments. They also emit more light in the blue spectrum, which suppresses melatonin, and result in negative impacts on human health. Nocturnal animals that may be roaming around may also be disturbed by them. Furthermore, white light headlamps would also create more light pollution as compared to red light ones. Therefore, try to invest in headlamps with multiple functions, namely the red LED mode. Another bonus is that red light is also less attractive to insects, and we all know how annoying it feels to have multiple bugs flyings all over your face!

NITECORE NU32 550 Lumen LED Rechargeable Headlamp, with Red Light

Red light is more ideal for use in nature. Source: Nitecore

Minimise Campfire Impacts
Campfires may generate light and smoke pollution and can have a drastic effect on fellow campers/hikers, as well as the environment. If you intend to set up a fire, make sure to keep it small and do it at a proper designated site, such as one that is contained in a fire ring, to reduce the risk of the fire spreading, as a fire without a border can easily spread with only a spark. Also, do check if the park that you are hiking in allows fires to be lighted in the first place.

campfire ring at a designated campground

Build fires only in designated fire rings, grills or fireplaces! Source: REI

Parting Words
Last but not least, do spread these awesome tips with fellow hikers and friends, before you put on your hiking boots and head into the great outdoors once the pandemic is all over! Let’s learn to be more sustainable and environmentally conscious, so that we can enjoy nature while protecting our parks!

Till we meet in the trails,

A New Hope – Biden Administration

About 2 months ago, I wrote a blog post about how the Trump administration has been undermining and weakening some of the important rules and standards that have been put in place by the Environmental Protection Agency (EPA) to improve the country’s air quality, as well as other climate-related issues. In fact, Trump’s skepticism and denial of climate change issues have been very apparent, even going so far as to accuse climate scientists of having “political agendas” about the earth’s rising temperatures. This has resulted in his administration to not only withdraw from the Paris Agreement, but to also roll back a number of environmental safeguards, thus undoing some of the important work that has been done to protect their public lands and National Parks.


Yesterday, Joe Biden has officially been declared as the next president of the United States of America. So what does that mean for the future of our planet, and our National Parks?

First and foremost, the fact that Biden has a Clear Plan For Clean Energy Revolution and Environmental Justice, is a very encouraging sign. Some of the highlights of his plan, such as the promise to cut emissions to be on track to reach net zero emissions by 2050, can be seen in the video below.

Secondly, Biden also plans on rejoining the Paris Climate Agreement, as stated in his tweet here. Leaving the Paris Climate Agreement was seen as huge disappointment by many, especially because the U.S is the world’s biggest and most powerful economy, and being the “only country to withdraw from a global solution to a global problem raises questions of trust”, as mentioned by McGrath (2020). By rejoining the Paris Climate Agreement, the U.S can continue to take the lead in addressing climate issues and also put the pressure on other nations to do the same.

Lastly, a shift from Trump’s administration’s anti-environmental record on National Parks and public lands, would mean that the National Parks Conservation Association (NPCA) can continue fighting for the future of its national monuments and bills supporting action on climate change and environmental justice, with the backing of the new Congress and Biden administration.

So my friends, not all hope is lost. Yes, promises can be made and subsequently not followed, but at least, the new administration under Biden’s leadership has shown us promising and encouraging signs of a clear, concrete plan to tackle the seemingly endless climate-related issues that not only affect their nation, but the rest of the world.

Till next time,


McGrath, M., 2020. Climate Change: US Formally Withdraws From Paris Agreement. [online] BBC News. Available at: <> [Accessed 8 November 2020].

National Parks Conservation Association. 2020. President-Elect Biden To Prioritize Conservation And Climate Change, Benefitting National Parks Across The Country. [online] Available at: <> [Accessed 8 November 2020].

Light Pollution in National Parks: Impacts and Importance

Now that we have understood the different components of light pollution, let’s take a look at some of its impacts, as well as find out the importance of night skies and naturally dark environments.

Impacts of Light Pollution
Human Health
There have been several studies on the severe health impacts of Artificial Light At Night (ALAN) on humans and other biotas. For instance, ALAN may suppress the body’s production of melatonin and influence our biological clock, also known as the circadian rhythm. The suppression of melatonin may also lead to irregular cell development and deactivation of cancer-suppressing genes, thus resulting in negative impacts on human health, such as the increased risks of obesity (Park et al., 2019) or cancers (Haim & Zubidat, 2015). Cho et al., (2015) also found that the health effects of ALAN are related to the exposure conditions and characteristics of the lights, and not only to the amount of light. This is similar to any other environmental pollutants that cause negative health effects, which are dependent on not just the amount but the exposure, as discussed during Lecture 2. There are also some studies that reported that the duration and the time of exposure to ALAN plays a huge factor in determining its negative health effects. For example, evening light exposure before bedtime affected the circadian phase more than did afternoon exposure. Thus, excessive exposure to artificial light does not involve only too bright light, but also too long or irregular exposure (Cho et al., 2015).

Disruption of the World’s Ecosystems
ALAN does not only affect humans, but animals too, as they depend on Earth’s daily cycle of light and dark rhythm to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators. As nocturnal animals sleep during the day and rise at night, the presence of excessive light at night radically alters their nighttime environment, which may cause drastic effects on nocturnal ecology. For example, a research study by Robert et al., (2015) shows that ALAN disrupts the reproductive cycle of wild wallabies on Garden Island, Australia, due to the significantly suppressed nighttime melatonin levels, thus resulting in a month-long delay in the birth of their offspring.  In consequence, mismatches with optimal food resources to raise their young may occur (Robert et al., 2015).

Experimentele groene verlichting met meer blauw en minder rood

Experimenting with green artificial lighting in the Netherlands to study the effects of light pollution on the health of animals. Source:

There have also been various experiments by ecologists that seek to study the effects of ALAN on ecosystems. A field experiment in the Netherlands which involved placing several rows of street lamps in eight locations, and the monitoring of the activities of small mammals, found physiological evidence of the detrimental effects of light pollution on the health of the animals. For instance, songbirds that were found to be roosting around the white light were restless through the night, and therefore slept less and had metabolic changes that could indicate poorer health (Irwin, 2018). Another project, known as Ecolight, made use of “glowing cubes” to look for evidence of the “cascade effects” of light pollution on the ecosystem and subsequently found some experimental evidence of a strong, bottom-up effect of exposure to artificial light (Irwin, 2018).

A mesocosm experiment of box lights at night

Artificial light in the form of “glowing cubes”, used to understand the ecological effects that it may bring about. Source: Irwin (2018)

Psychological Health
According to a laboratory study of the psychological impact of light pollution in national parks, participants who experienced even moderate levels of light pollution reported lower mood scores as well as lessened scenic quality when compared to lower light pollution scenes. This suggests that pristine night skies in national parks could become important for creating satisfying visitor experiences and preserving the beneficial outcomes associated with natural scenery (Benfield et al., 2018). While this may seem like a stretch, there has also been another study that found a statistically significant relationship between ALAN and measures of depression and suicidal ideation among Korean adults. This further expounds the multiple detrimental health and psychological impacts on both humans and ecosystems.

Importance of Night Skies and Naturally Dark Environments
Like clean air and water, wildlife, or the sounds of nature, a clear dark night sky is an intrinsic part of the national park experience. According to visitor surveys at two National Parks in Utah, 99% of visitors prefer to stargaze in a national park over other locations, while 80% indicated that the quality of night skies was an important part of their visit (Mace and McDaniel, 2013). Hence, many of them also felt that efforts should be made to protect dark skies in national parks, and that the surrounding communities should help support such protection.

Grand Canyon Officially Awarded Dark Sky Park Status

Grand Canyon National Park, earned its status as a Dark Sky Park by the IDA in 2019. Source: Matthews (2019)

Astrotourism and its Economic Value
The growing public appreciation for activities involving nighttime programs and stargazing has also spawned a new form of tourism- astrotourism. Astrotourism involves people travelling to nature-rich destinations like national parks, that experience considerably less amount of light pollution, which in turn allows visitors to spot starts and constellations more easily. These places are often categorized as “dark sky parks/reserves”, by the International Dark-Sky Association (IDA), which has identified them as places that implement good outdoor lighting and provide dark sky programs for visitors, as well as places where policy controls are enacted to protect the darkness of the location. Another way of finding places that can offer pristine dark sky areas, is through the dark site finder, that highlights places based on a dark-bright scale, as shown below. As a result of these astrotourism activities, additional spendings through other means such as food and lodging could bring about increased revenue for the local economy as well. According to a case study on The Colorado Plateau that is known for its dark skies, the current economic impact of astrotourism activities is substantial, where the increasing number of visitors may contribute to the creation of more jobs, as well as increase wages and gross state product (Mitchell and Gallaway, 2019). Hence, with the increase in efforts to promote night sky or astrotourism, the economic impacts would continue to grow substantially (Mitchell and Gallaway, 2019).

Location of Dark Sites in the USA. Source:


Till next time,


Benfield, J., Nutt, R., Taff, B., Miller, Z., Costigan, H. and Newman, P., 2018. A laboratory study of the psychological impact of light pollution in national parks. Journal of Environmental Psychology, 57, pp.67-72.

Cho, Y., Ryu, S., Lee, B., Kim, K., Lee, E. and Choi, J., 2015. Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment. Chronobiology International, 32(9), pp.1294-1310.

Haim, A. and Zubidat, A., 2015. Artificial light at night: melatonin as a mediator between the environment and epigenome. Philosophical Transactions of the Royal Society B: Biological Sciences, 370(1667), p.20140121.

Irwin, A., 2018. The Dark Side Of Light: How Artificial Lighting Is Harming The Natural World. [online] Available at: <> [Accessed 4 November 2020].

Mace, B. and McDaniel, J., 2013. Visitor Evaluation of Night Sky Interpretation in Bryce Canyon National Park and Cedar Breaks National Monument. Journal of Interpretation Research, 18(1), pp.39-57.

Mitchell, D. and Gallaway, T., 2019. Dark sky tourism: Economic impacts on the Colorado Plateau Economy, USA. Tourism Review, 74(4), p.937.

Park, Y., White, A., Jackson, C., Weinberg, C. and Sandler, D., 2019. Association of Exposure to Artificial Light at Night While Sleeping With Risk of Obesity in Women. JAMA Internal Medicine, 179(8), p.1061.

Robert, K., Lesku, J., Partecke, J. and Chambers, B., 2015. Artificial light at night desynchronizes strictly seasonal reproduction in a wild mammal. Proceedings of the Royal Society B: Biological Sciences, 282(1816), p.20151745.

Light Pollution in National Parks: An Overview

Hello all!

After watching Week 9’s lecture on light pollution, I began to wonder if this problem is only present in urban areas, and whether there are any effects and implications on the national parks that are surrounding these areas. All it took was a quick google search, to shed some light on the situation. One of the articles that I came across was about how the Death Valley National Park, which was certified as a Dark Sky Park by the International Dark-Sky Association (IDA) in 2013, still faces issues of light pollution at night, caused by the nocturnal glow of Las Vegas and surrounding cities, despite being located about 65km away.

Far-reaching effects of light pollution. Source: Claire Turell

Let me show you another photograph which perfectly encapsulates this phenomenon.

Lights from Los Angeles visible from a rural road located 144km away. Photograph by Babak Tafreshi

This is indeed a rather surprising discovery. You’d think that remote places like these would not experience the effects of light pollution from the brightly lit cities located more than a hundred km away! In fact, according to this National Geographic online article, light pollution can travel more than a whopping 217 miles (350km) from its source, thus affecting a rather massive area. Let’s now dive deeper and find out more about light pollution and why its effects are far-reaching.

What is Light Pollution?
According to the definition by IDA, light pollution is the inappropriate or excessive use of artificial light. It is comprised of various components, such as glare, skyglow, light trespass and clutter. The infographic below illustrates the different components that are associated with light pollution.

Glare – Excessive brightness that causes visual discomfort
Skyglow – Upward, directed or reflected light. Brightening of the night sky over inhabited areas
Light Trespass – Light falling where it is not intended or needed
Clutter – Bright, confusing, and excessive groupings of light sources

Different components of light pollution. Source: Anezka Gocova, in “The Night Issue”, Alternatives Journal 39:5 (2013).

Main types of light pollution that can affect National Parks
The two main types of light pollution that can affect remote places like National Parks are skyglow and glare. Skyglow occurs due to the scattering and reflection of light off air molecules and atmospheric aerosols (Turina, 2018). As a result, we observe anthropogenic light originating on the ground as luminance in the sky. Skyglow also diminishes the aesthetics of the night sky and illuminates the observer and the landscape unnaturally. We all know the wondrous feeling of seeing the amazing grandeur of a star-filled night sky, the cosmos, and the starry constellations. Sadly, skyglow has the potential to disrupt this experience.

Suburban neighbourhood showing the location of sky glow, glare and light trespass. Source: Let’s Talk Science

Glare is stray light that strikes our eyes directly from a source. It degrades the visual scene by obscuring visual information. As our eyes automatically adjust to the brightest source of light in a scene, the presence of glares, such as an unshielded lighting fixture, would cause us to have difficulty to see the area surrounding the light. This leads to the loss of visual information in the vicinity of the light (Turina, 2018). Glare also affects our scotopic vision. Scotopic vision refers to the vision of our eyes under low-light levels, aka “Night Vision”. Human vision maintains sensitivity over an impressively large range of ambient light levels. Even though humans maintain visual sensitivity in dark areas, it can take several hours to fully adjust to low light conditions. However, according to the American Optometric Association, dark adaptation can be lost in a matter of seconds upon exposure to bright light.

In the next blog post, we will be discussing more on the importance of night skies and naturally dark environments, as well as the various impacts that light pollution may have on humans and wildlife.


Till next time,


Mace, B. and McDaniel, J., 2013. Visitor Evaluation of Night Sky Interpretation in Bryce Canyon National Park and Cedar Breaks National Monument. Journal of Interpretation Research, 18(1), pp.39-57.

Turina, F., 2018. Protecting Night Skies And Naturally Dark Conditions In National Parks. Madison, Wisconsin: U.S. Forest Service.

Water Pollution in National Parks: Case Study of Kruger National Park in South Africa

So far, we have discussed about air, noise and land pollution issues that are prevalent in national parks. In this blog post, the focus will be on another type of environmental pollution- water pollution, specifically in Kruger National Park (KNP) in South Africa. I will be adopting the “Message Box” approach that we have learned from Tutorial 1, to unpack and summarise key information from a journal article on the impacts of pollution in KNP. The main source that I will be drawing information from, is a journal article titled “Pollution impacts on the aquatic ecosystems of the Kruger National Park, South Africa”, which was written by Riddell et al. and published in the Scientific African journal in 2019.

But first, let’s take a quick look at a video that summarizes the problems of water pollution that the KNP is facing today.

Source: South African Broadcasting Corporation (SABC) Youtube Channel

The KNP is a savanna ecosystem that is situated in the middle reaches of a few sizeable and biologically diverse transboundary river systems. Over the last 30 years, the KNP has been at the forefront of applied river ecosystems research due to the various challenges that the rivers face- which have often arisen from anthropogenic changes in the catchments of the park. The resultant challenges give rise to a multitude of effects that bear upon the parks’ capability to maintain the viability of aquatic ecosystems in a large and biodiverse landscape.

Main Rivers of the KNP (South African National Parks)

Various Stakeholders that are responsible for the management of the KNP, such as the South African National Parks (SANParks) and the Olifants Catchment Management Agency, as well as the users of the rivers, such as the densely populated peri-urban settlements who rely on the water from the river for agriculture and irrigation.

To get an overview of the challenges that the KNP face in terms of upstream pollutants and its impact on the aquatic ecosystems. Since it is the responsibility of the KNP to conserve these important ecosystems, the focus on the effect of diffuse pollutant impacts to the freshwater aquatic biota as well as the diversity of these impacts will be explored.

Water pollution in the rivers of the KNP as a result of mining activities and municipal wastewater problems.


  • Cyanide spills occur from extensive mining of copper and phosphate along a tributary of the Olifants River at KNP’s western boundary. The mining expansion in the Olifants River suffered serious salt enrichment, mainly from the sulphate and phosphate through controlled effluent discharge
  • There is little oversight of the licenses of industrial mining facilities that sets out how much water it can use and what quality of water it can release into the river, especially for mines owned by people with political connections (Kings, 2017)
  • Municipal wastewater treatment plants release polluted water more often than not. These plants are generally acknowledged in the environment sector as being the single worst source of pollution in South Africa (Kings, 2017)
  • There is no systemic eco status monitoring that is taking place in the KNP’s northern rivers for at least 20 years and this is a cause for concern. Only the Crocodile and Sabie systems are being monitored by the Inkomati-Usuthu Catchment Management Agency (IUCMA)

Bosveld Phosphates pollutes Kruger rivers, causing acidic waters and resulting in the death of fishes (Kings, 2014)

So What?

  • Point and diffuse sources create a cascade of environmental pressures, such as affecting the mortalities of species like the Nile crocodile
  • The manifestation of diseases as a result of upstream pollution impacts and eutrophication leads to a trophic level shift, with both crocodiles and sharp-tooth catfish changing to a more piscivorous diet
  • Discernible effects of heavy metal bioaccumulation as a result of mining activities in the Olifants catchment
  • Impacts on top predators such as the Tigerfish in the aquatic food chains
  • Diffuse accumulation of Copper, Mercury and build up in egg-shells of crocodiles in the Olifants River, resulting in an eco-toxicological effect
  • Intermittent fish kills arising from anoxic sediment sluicing
  • Serious human health risks associated with regular subsistence of protein consumption of tissue from fish
  • People using untreated water from these contaminated sites (along the Olifants) face a high risk of contracting diseases, such as diarrhoea and E coli


  • Rivers supply valuable water resources for domestic water supply, irrigation farming, industrial and mining developments. Tackling the pollution related issues in the KNP would thus provide important economic and social benefits to the users of both South Africa and Mozambique.
  • Conserve the ecosystems and the biodiversity in the KNP
  • Ensure safe water supply to tourist camps in the park that are dependent on the water from the Olifants River
Kruger National Park wildlife at watering hole

Kruger National Park wildlife at watering hole. Source: Secret Africa


  • The rivers of Kruger cannot be managed in isolation from the rest of the catchment area upstream of the park, but will need to align with integrated catchment management processes
  • Categorising different rivers for various management options and setting up relevant institutions to oversee water resources within the 19 water management areas throughout the country
  • Adopt a more stringent approach in ensuring that industrial mining activities follow the regulations set out for them, and punish those who do not stick by them, such as through heavier fines.
  • Promote awareness of the benefits of conserving river biodiversity within the water management areas by tackling the prevalent pollution issues in the KNP


Till next time,


Kings, S., 2017. A River Of Shit, Chemicals, Metals Flows Through Our Land. [online] The Mail & Guardian. Available at: <>

Kings, S., 2014. Bosveld Phosphates Pollutes Kruger Rivers, Again. [online] The Mail & Guardian. Available at: <>

Riddell, E., Govender, D., Botha, J., Sithole, H., Petersen, R. and Shikwambana, P., 2019. Pollution impacts on the aquatic ecosystems of the Kruger National Park, South Africa. Scientific African, 6, p.e00195.

Siyabona Africa. n.d. Managing Kruger’s Rivers. [online] Available at: <>

Ingenious Response of National Park Officials to Litterbugs

How can you remind visitors of National Parks of their thrashy and irresponsible behaviour?

Simply mail it back to them!

That is the strategy that government officials from Thailand have adopted to stress the importance of not littering in the natural environment. Khao Yai National Park, which is a UNESCO World Heritage site located about 200km northeast of Bangkok, has seen countless of littering cases by visitors after its reopening on July 1. This has resorted to the Environmental Minister Varawut Silpa-archa to posting pictures of delivery boxes containing trash bags filled with various form of litter on his Facebook account.

“I will pick up every single piece of your trash, pack them well in a box and mail it to your home as a souvenir,” the minister, said in the post.

Garbage left by campers in Thailand was packed up and mailed back to them with a note reading, “You have forgotten some of your belongings at the Khao Yai National Park.”

Garbage left by visitors in Thailand’s Khao Yai National Park, was packed up and mailed back to them with a note reading, “You have forgotten some of your belongings at the Khao Yai National Park.” (Thailand Ministry of National Resources and Environment)

Visitors to the park have to register with their addresses, which makes it easy for park officials to track them down (with some investigative work) if they leave rubbish behind. In his facebook post, The Environmental Minister also listed the regulations, which included that violators who perform actions that harm natural resources and the environment can receive up to five years in prison, up to a 500,000 Thai Baht (about $16,000) fine, or both. He concluded the post with a message of “Travel with conscience. Let’s maintain cleanliness and save the environment. Because from now on, we will take strict legal action.”.

Another national park in the U.S, Glacier National Park, has taken a slightly similar approach, albeit in a less serious manner. In their facebook page, they uploaded a meme post that has an image of a dumpster with the caption, “This is a trash receptacle” above it, next to a picture of a pristine mountain and lake landscape noted with the caption, “This is a national park.”

“Don’t mix these two up! Anything you bring into a national park, you must pack out or dispose of in a proper trash receptacle. Do not hit golf balls into canyons and valleys, do not leave used diapers on the sides of trails, do not toss your apple core because you think it’s natural. National parks have been called America’s best idea. Don’t treat them like a garbage can.” This is the message that was attached to the same Facebook post.

While these responses by National Park officials seem unusual and tongue-in-cheek, they also carry with them serious messages to the audience. Not only is literring a crime, but it can also lead to grave environmental consequences, as highlighted in my previous post.

With that, I shall conclude my post with an image that perfectly encapsulates a very simple message- one which I am sure that you’ve heard of before.

Till next time,


May, T., 2020. Left Litter In The Park? Thailand Officials Will Mail It To Your Home. [online] The New York Times. Available at: <> [Accessed 10 October 2020].

Romano, A., 2019. Please Don’t Treat National Parks Like A Garbage Can, Says Glacier National Park. [online] Travel + Leisure. Available at: <> [Accessed 10 October 2020].

Littering in National Parks: How It Leads To Various Forms of Pollution

Littering, which is an act of improper disposal of waste products, can happen intentionally or unintentionally. It can take a variety of forms, such as cigarette butts, food wrappers and plastic bottles. Littering can also occur pretty much anywhere in the world. For instance, Mount Everest has been dubbed as the world’s highest rubbish dump. As the number of commercial hikers and mountaineering enthusiasts visiting the peak soar, so too has the amount of trash left behind. This also presents a huge challenge in cleaning up the garbage due to the complexities of bringing them down from high altitudes.

Mount Everest Müll (Getty Images/Afp/Namgyal Sherpa)

Climber clearing empty gas canisters in Mount Everest (Getty Images)

Besides the problems associated with cleaning up the trash, littering can cause serious consequences for the environment too. There are various forms of pollution that are associated with littering. According to Taylor (2018), more than 100 million pounds of garbage are generated by national park visitors in the US each year.  In this blog post, I will be expanding on the topic of littering in the context of national parks, and how it leads to environmental pollution.

How littering results in Water Pollution
Do you know that 60% of water pollution is attributed to litter? This is primarily due to the fact that litter that is thrown on the ground often gets washed into water bodies and freshwater sources such as rivers and lakes, which could eventually end up in storm drains and directly into our waterways. Waterway litter harms and kills marine wildlife, causing the death of at least 100,000 marine mammals worldwide annually. This occurs in various ways, such as marine animals mistaking microplastics as food and subsequently consume them, or the degradation of water quality due to the toxins and chemicals released from litter such as cigarette butts (which contains chemicals such as arsenic and formaldehyde). As mentioned in lecture 5 on the topic of marine pollution, plastic also carries with it toxins known as persistent bioaccumulative and toxic substances [PBTs]. PBTs have the tendency of being transferred to organisms when plastic debris is consumed. An example of this is a study by Ryan et al (1988), which shows great shearwaters (Puffinus gravis), a seabird known to ingest plastic, had PCB concentrations in fat tissues corresponding to the amounts of plastic found in their stomachs (US EPA, n.d.)

A milk bottle being picked up by a litter picker

Plastic bottles being cleared in Snowdonia National Park (Snowdon Society)

Trash and debris in rivers may also result in habitat alteration. As debris accumulates, light levels may be reduced in the benthic zone, which leads to the depletion of oxygen levels as well. Benthic refers to anything that occurs on the bottom of a body of water such as a river, lake or ocean. As a result, the ability of benthic habitats to support aquatic life is undermined. This results in further implications, such as the decline in benthic habitat-forming species and species that are dependent on these habitats for foraging and shelter (US EPA, n.d.)

How littering results in Soil Pollution
Over 400 million tons of plastic are produced globally each year, and it is estimated that one-third of all plastic waste ends up in soils or freshwaters. As plastics are often considered to be one of the most common forms of litter in the world, they also present a threat to terrestrial ecosystems in national parks. This is due to the impact of microplastics in soils and sediments which could have a long-term negative effect on these ecosystems, based on a study done by De Souza Machado et al., (2018).  Microplastics are essentially plastics from litter that disintegrates into particles smaller than five millimetres. They can even be broken down further into nanoparticles, which are less than 0.1 micrometre in size. In fact, terrestrial microplastic pollution is much higher than marine microplastic pollution — an estimate of four to 23 times more, depending on the environment (De Sourza Machado et al., 2018).


Potential Impacts of Microplastic on Terrestrial Organisms (De Sourza Machado et al., 2018)

Microplastics can also interact with soil fauna, affecting their health and soil functions, due to its persistence of more than 100 years as a result of low light and oxygen conditions.  For instance, the earthworm’s fitness and soil function is affected as they have to make their burrows differently when microplastics are present in the soil. Additionally, microplastics could also affect soil chemistry, texture, structure and function, as highlighted in De Sourza Machado et al., (2018).

How littering results in Air Pollution
While littering may not directly result in air pollution, it presents a possibility of wildfires occurring. This is because litter is often composed of flammable materials, which may trigger the start of a wildfire from lighting or a small spark. Another possibility is the accidental lighting up of litter when discarded cigarette butts are not fully put off. When wildfires occur, outdoor airborne particles and gaseous air pollutants such as carbon monoxide, nitrogen dioxide, formaldehyde and acetaldehyde experiences substantial increase. Hence, air pollution may spread over thousands of square kilometres and affect populations living far away from the locale of the wildfire itself.

Smoke from fires in Siberia has blown as far as Alaska, Canada and US cities including Seattle (Credit: Julia Petrenko/Greenpeace)

Heavy smog caused by wildfires (Petrenko)

How littering results in Visual Pollution
Visual pollution is defined as the impairment of the view of an individual due to environmental and man-made factors, although they are most commonly caused by human actions like littering. Visual pollution can have significant effects on health and the well-being of people, as it may result in discomfort and stress for those who experience them. This is especially so for places like national parks, which are often regarded as natural sanctuaries for visitors to relax their mind and enjoy being in the presence of nature. Just imagine yourself walking on a hiking trail, enjoying the sights and sounds of nature, and then coming across a huge pile of trash along the way. Won’t that ruin your mood and experience?

A picture taken by yours truly, on a hiking trail in the Meili Snow Mountain National Park, China

Sometimes, all it takes is an irresponsible individual to start littering.. and others may very well follow suit after that, thus creating a perpetual cycle.

Till next time,


De Souza Machado, A., Kloas, W., Zarfl, C., Hempel, S. and Rillig, M., 2018. Microplastics as an emerging threat to terrestrial ecosystems. Global Change Biology, 24(4), pp.1405-1416.

US EPA. n.d. Impacts Of Mismanaged Trash. [online] Available at: <> [Accessed 9 October 2020].

Noise Pollution in National Parks: Protecting National Park Soundscapes

Hello everyone! In my previous blog post, I’ve touched on the impacts of noise pollution that have been increasingly pervasive in National Parks, and how it impacts both the environment and human health. Who would’ve thought that anthropogenic noise can affect even plants (albeit indirectly) too?! The problem of noise pollution is increasingly pervasive, and therefore, various studies have been done to figure out how we can protect the soundscapes of our national parks and ensure that both visitors and wildlife get to experience natural quiet and sounds of nature. This blog post seeks to discuss further.

A Case Study at Muir Woods National Monument involving Quiet Zones
The NPS Natural Sounds Program Office was established in 2000; with a mission of “articulating the various operational policies that will require, to the fullest extent practicable, the protection, maintenance, or restoration of the natural soundscape resource in a condition unimpaired by inappropriate or excessive noise sources”. Hence, it has supported a program of research at Muir Woods National Monument, which was designed to support noise management. One of the ways in which the NPS  addressed the issue, is through an educational program that was developed to sensitize visitors to human-caused noise at the park, and to encourage them to reduce the noise they generated. This was done through experimental treatments involving quiet zones that were established in various parts of the park.

An NPS staff setting up an acoustic recording station (National Parks Service)

The first treatment utilised a series of signs that were placed throughout the park that designated Cathedral Grove (which is located 800m from the park entrance) as a “quiet zone”, whereas the second treatment utilised signs declaring “quiet days” throughout the park. Both set of signs also requested visitors to turn off their mobile phones, encourage children to walk quietly, and talk in a lowered voice. Meanwhile, there were also days without any signs, which served as experimental controls. Surveys were also generated to find out more about the perceptiveness of the educational treatments by the visitors. Based on the survey findings, a significant percentage of visitors reported that they consciously limited the amount of noise they made in the park after observing the signs, which indicates a high level of compliance with the educational messages. This is further complemented by the fact that the quiet zone approach caused sounds levels to decrease by almost 3 dB! This shows that educational programs and interpretive materials in the form of signages (which is a seemingly straight forward approach) have the added benefit of helping visitors be more conscious of the park’s acoustical environment and the value of natural, uninterrupted sounds.

America's noisiest and quietest national parks — the human factor -

“Enter Quietly” sign in Muir Woods National Monument

Focusing Noise Reduction on Major Roads and Highways
There are a number of national parks that are in close proximity of roads and highways. Therefore, the most common methods of noise reduction focus on quieting major roads and highways. A typical approach would be to introduce large walls that block noise from the surrounding area. These barriers can be built from various materials (concrete, wood, metal), as long as they adhere to a certain density. According to the Federal Highway Administration (FHWA) (2011), noise barriers can achieve a 5 dB noise level reduction, when it is tall enough to break the line-of-sight from the highway to the home or receiver, and another 1.5 dB reduction after it breaks the line-of-sight, for each meter of barrier height. Despite the effectiveness of noise barriers, it comes with certain limitations too. As noise barriers must be tall enough and long enough to achieve the desired effects on noise, it may be an expensive solution. Additionally, they may require frequent maintenance, such as preventing holes that may reduce its effectiveness.

Noise Reduction by a Vertical Barrier (FHWA, 2011)

An alternative method involves the use of earth berms. Earth berms are raised barries that are made from compacted soil. However, according to a Guidelines for the Use of Earth Berms to Control Highway Noise, earth berms with normal surfaces (grass over soil) were found to provide about 2 dB less noise reduction than walls of the same height and position. This is due to the fact that sound waves which strike the berms inclined front face gets reflected/scattered towards the crest of the berm. Hence, the gradient of the berms may affect how much noise it is able to reduce. The slopes of earth berms also consume substantial space, which means that berms cannot be built as close to traffic as can noise walls. Therefore, there is another option of combining both earth berms and walls, which may lead to an improvement in noise reduction. This is because the berm reflected/scattered sound waves have a higher tendency to cancel (FHWA, 2011). However, the walls would have to be placed on top of an earth berm that is flat-topped, and of normal softness. The FHWA has elaborated further on the optimal berm/wall configurations, as seen here.

Last but not least, modifications can be made to the roadway itself. For instance, increasing the porosity of pavements may reduce the propagation of noise and prevents tire noise due to a smoother horizontal surface and greater elasticity, as compared to normal roads that are made of asphalt and concrete without indentations. However, porous roads are less resilient than traditional roadways, as dust can clog the pores and diminish the noise-reduction potential. They also require more frequent maintenance than standard asphalts or concretes (Abad et al., 2017).

Monitoring and Management
Ultimately, noise levels have to be monitored again after mitigation measures have been introduced, in order to determine whether longer-term strategies (such as visitor education, quiet zones and addition of barriers) had significant effects on noise reduction. Additionally, these repeated recordings allow sound levels to be tracked over long periods of time, making larger trends more observable, so that future interventions can be targeted more effectively (Abad et al., 2017).

Till next time,


1997. Noise Control Earth Berms. Victoria, B.C.: Highway Engineering Branch, Ministry of Transportation and Highways, pp.1-26.

Abad, B., Dings, A., Farnitano, D. and Weissman, Z., 2017. Preserving The Soundscape: Exploring Ways To Mitigate Sound Pollution In Acadia National Park. Undergraduate. Worcester Polytechnic Institute.

Federal Highway Administration. 2001. Keeping The Noise Down, Highway Traffic Noise Barriers. [online] Available at: <>

Kaplan, S., 2017. Human Noise Pollution Is Everywhere, Even In The National Parks. [online] The Washington Post. Available at: <>


Noise Pollution in National Parks: Impacts on The Environment and Human Health

As mentioned in my previous post, anthropogenic noise is an increasingly pervasive threat in national parks, and this is indeed a cause for concern as national parks are not only refuges of natural ecosystems, but also important sanctuaries for people to take some time out to relax and revitalise in the presence of nature. In this post, I will be sharing more about how noise pollution in national parks impacts the wildlife present in them, as well as the psychological well-being of park visitors who frequent them.

Impacts of noise pollution on wildlife and the environment
Animals rely heavily on their ability to hear the subtle sounds of nature — the movement of predators, the trickle of a stream. Those sounds may be masked by noise pollution, which puts wild creatures at risk (Kaplan, 2017). Noise from human activity is also frightening and distracting; it can change animals’ behaviour with consequences for the entire ecosystem. According to a study by Chan and Blumstein (2011), anthropogenic noise may draw attention and thus distract animals. This is because animals generally respond to a very narrow range of stimuli as attention filters out irrelevant information. As a result, it leaves them less able to attend to a stimulus important for survival or reproductive success. This is reflected in an experiment which shows how a continuous white noise impaired the ability of Norway rats to perform a visual discrimination task, which implies that anthropogenic stimuli may broadly influence an animal’s performance visual tasks, even if the stimuli are not visual. Rising noise levels may also result in direct negative fitness consequences for avians, as studies have shown that many bird species are less abundant near highways, due to reduced reproductive success in noisy territories (Slabbekoorn and Ripmeester, 2008).

A red fox listening for prey under the snow in Yellowstone National Park. Photo by Neal Herbert/NPS

It is also worth to note that attentional capabilities are taxonomically widespread, which means that noise pollution may affect a wide group of species, as illustrated in the image below. Kunc and Schmidt (2019) thereby concluded that anthropogenic noise must be considered as a serious form of environmental change and pollution, as it affects all kinds of animal species. Therefore, given the ample empirical evidence, legislative bodies should develop a robust legal framework to protect species from increasing anthropogenic noise effectively (Kunc and Schmidt, 2019)

Effects of anthropogenic noise on taxonomic groups. Graphics taken from Kunc and Schmidt (2019)

Anthropogenic noise may affect plants, too, mainly due to the fact that some plants rely heavily on animals to pollinate and spread their seeds. For instance, a research conducted by Francis et al. (2012) found that western-scrub jays avoided noisy areas and therefore stopped contributing to the pollination of the piñon pine tree seeds. As a result, the seeds were consumed by mice, and the survival of the piñon pine tree species may be interfered. This shows that even though noise pollution affects certain animal species directly in terms of their behaviour, there may be cascading effects throughout the ecosystem, and large-scale changes may occur due to the responses of some important species (Sohn, 2012).

Impacts of noise pollution on human health
Noise pollution in National Parks may also affect our health too. According to recreation researchers, a primary reason for visiting a national park is to escape the stressors found in urban areas. This is due to the restorative value of being in nature — appreciating the expanse of a scenic vista and enjoying the tranquillity of natural sounds (Mace, Bell and Loomis, 2004). However, the intrusion of noise pollution into preserved natural areas are getting more common. This is a huge concern, as psychological research has shown that visitors to natural settings are sensitive to low levels of human-caused noise, which detracts from the enjoyment of the experience. Negative experiences may then lead to certain psychological needs remaining unfulfilled, especially when considering the primary reasons for visiting national parks, thus leading to negative long-term consequences for visitors. Another study by Iglesias Merchan, Diaz-Balteiro and Soliño (2014) found that human-voice pollution are also easily visible by receivers, such as loud talking, which may detract from the visitor experience as well.

In the next blog post, we will take a look at some of the measures that have been taken to reduce the pervasive problem of noise pollution in national parks.

Till next time,


Chan, A. and Blumstein, D., 2011. Attention, noise, and implications for wildlife conservation and management. Applied Animal Behaviour Science, 131(1-2), pp.1-7.

Francis, C., Kleist, N., Ortega, C. and Cruz, A., 2012. Noise pollution alters ecological services: enhanced pollination and disrupted seed dispersal. Proceedings of the Royal Society B: Biological Sciences, 279(1739), pp.2727-2735.

Iglesias Merchan, C., Diaz-Balteiro, L. and Soliño, M., 2014. Noise pollution in national parks: Soundscape and economic valuation. Landscape and Urban Planning, 123, pp.1-9.

Kaplan, S., 2017. Human Noise Pollution Is Everywhere, Even In The National Parks. [online] The Washington Post. Available at: <>

Kunc, H. and Schmidt, R., 2019. The Effects Of Anthropogenic Noise On Animals: A Meta-Analysis. Biology Letters.

Mace, B., Bell, P. and Loomis, R., 2004. Visibility and Natural Quiet in National Parks and Wilderness Areas. Environment and Behavior, 36(1), pp.5-31.

Slabbekoorn, H. and Ripmeester, E., 2008. Birdsong and anthropogenic noise: implications and applications for conservation. Molecular Ecology, 17(1), pp.72-83.

Sohn, E., 2012. Noise Pollution Affects Plants, Too. [online] NBC News. Available at: <> [Accessed 27 September 2020].

Noise Pollution in National Parks: Is It A Cause For Concern?

Imagine this. You are getting weary from the hustle and bustle of the city life. The din of the vehicles, the commotion of urban dwellers, the incessant pounding of jackhammers in construction sites.  You are longing for a quiet respite, perhaps somewhere in the woods, where you can finally take a breather and escape from the city noise. So you make your way to a national park, where the sound of nature is so subtle that they’re almost imperceptible. But every now and then, the sound of a jet flying overhead shatters the fragile calm. You’re in the wilderness, in the middle of nowhere, yet you still can’t fully escape anthropogenic noise.

The pervasiveness of noise pollution in National Parks
That’s the problem with noise pollution. It doesn’t have any boundaries, and it pervades the wilderness areas across the country. According to a study by Buxton et al. (2019) where thousands of hours of acoustic recordings were collected across various national parks in the U.S. and subsequently analyzed, anthropogenic noise was audible in 37% of the recordings. The study also found that parks with high road density and those in close proximity to large airports are more vulnerable to noise events, as the most common noise sources were aircraft and road vehicles.

Some examples of anthropogenic noise sources in US national parks include (a) aircraft (Theodore Roosevelt National Park, North Dakota), (b) vehicles (Denali National Park and Preserve, Alaska), (c) trains (Cuyahoga Valley National Park, Ohio), and (d) watercraft (Glacier Bay National Park, Alaska). Graphics from Buxton et al. (2019)

Another study by Iglesias Merchan, Diaz-Balteiro and Soliño (2014), which was done to evaluate the soundscape in a protected natural area, found that there was a noticeable soundscape degradation during visitors’ leisure experience, where sound pressure levels increased approximately 4.5 dB from natural ambient levels. Soundscape, a term that was first defined as the “acoustic footprint of a landscape”, refers to the collection of sounds that emanate from landscapes and reflect ecosystem processes and human activities over space and time. While repetitive events such as overflights or accelerating vehicles are able to cause a very significant environmental impact on the natural soundscape, the study found that human shouts or loud voices are also particularly significant, and loud talking is a good indicator of quality that detracts from the visitor experience, thereby becoming an issue for park management to consider.

Is it a cause for concern?
According to the World Health Organization (WHO) and the European Centre for Environment and Health (2011), unwanted or disturbing sounds (noise) may not only be a harmful pollutant to human health, but may also become a global and growing matter of concern threatening the preservation of natural areas, due to various reasons such as wildlife disturbance, ecosystems degradation and biodiversity loss. Additionally, natural soundscape loss or degradation may also have a substantial impact on aesthetic and affective visitors’ experiences, representing a depletion of ecosystem services linked to people’s psychological well-being in areas of pre-supposed environmental quality, as highlighted in Mace, Bell and Loomis (2004).

In the next post, I will be discussing more on the impacts of noise pollution in national parks on both the environment, as well as human health.

Till next time,


Buxton, R., McKenna, M., Mennitt, D., Brown, E., Fristrup, K., Crooks, K., Angeloni, L. and Wittemyer, G., 2019. Anthropogenic noise in US national parks – sources and spatial extent. Frontiers in Ecology and the Environment, 17(10), pp.559-564.

Iglesias Merchan, C., Diaz-Balteiro, L. and Soliño, M., 2014. Noise pollution in national parks: Soundscape and economic valuation. Landscape and Urban Planning, 123, pp.1-9.

Mace, B., Bell, P. and Loomis, R., 2004. Visibility and Natural Quiet in National Parks and Wilderness Areas. Environment and Behavior, 36(1), pp.5-31.

World Health Organization European Centre for Environment and Health, 2011. Burden Of Disease From Environmental Noise – Quantification Of Healthy Life Years Lost In Europe. [online] Copenhagen: World Health Organization. Available at: <>