Single Amphibian Individual in Still Creek

This observation was made in Burnaby, from the 18th floor of a building that is located close to a segment of Still Creek (approximately 60m). A railway runs parallel to the creek, past the building on the other side of the creek. This observation was made from a balcony which faces the creek and railway. This segment of Still Creek experiences slow to still water flow and is surrounded by tall grasses and riparian vegetation. This area also has tree cover and shade. The water in this creek is not very deep and is heavily silted. During rainy periods, the water level rises and floods a nearby open grassy area, which functions as a wetland. Although this is an ecologically rich area, habitation is hindered by the noise and vibration of the adjacent railway.

The observation was first made on March 27. A distinct frog or toad call could be heard originating from the wetland area of Still Creek. The calls can be described as two short notes resembling the classic “ribbit” croak associated with Frogs in popular media. Each instance of a call would be separated by 15-20 seconds of silence. Calls would occur periodically for several hours before subsiding. Given these attributes, it is assumed that a single individual amphibian was making the call. Amphibian calls have not previously been heard here. The calls were observed between March 27 and April 13. They have not been heard since April 13 as of the date of this paper.

A review of BC’s Conservation Data Centre (CDC) Species & Ecosystem explorer revealed several candidate amphibian species with the potential to occur in the Lower Mainland Ministry of Environment region. Through resources such as NatureWatch, a volunteer environmental monitoring/observation service founded in partnership with Environment and Climate Change Canada, audio recordings of amphibian calls were accessed. Calls of the potential species were reviewed. After a review of frog and toad calls, the closest match (by far) was the Pacific Treefrog, assumed to be from the Northern Pacific Treefrog population. This species is not endangered or of concern, but its occurrence in this area is very uncharacteristic.

The railway, located immediately south of the creek, regularly generates significant noise and vibration, causing severe disruption to amphibian habitation. Amphibians are rarely able to inhabit an area with constant vibration and noise. Not only do they need relative quiet to exercise their vocal communication, they are also physically stressed out by anthropogenic noise and vibration (Kaiser et al, 2015; Simmons & Narins, 2018). Between five and six trains regularly pass through this area per day, sometimes activating their horns, accompanied by the dinging bell of a nearby railway road crossing. However, starting some time in February, railway traffic had significantly diminished in the area. The recent railway protests staged by First Nations groups, advocates and supporters had caused significant disruptions to train movement (Jackson, 2020). These protests were resolved at the end of February. However, almost immediately following the resolution of the protests, the COVID-19 pandemic had caused a near shutdown of economic activity, keeping train traffic from returning to normal (Jackson, 2020). During late February and all of March, almost no trains were observed to pass through the area. The level of noise generated in the area had been reduced significantly. Approximately three weeks after the railway had fallen silent, the first instances of the amphibian call were observed. Within the first few days of April, trains began to pass through the tracks once again. At least one train could be expected to pass each day. The amphibian calls were still heard for approximately a week, but were not heard again since April 13. As of the date of this paper, train traffic appears to be back to its usual level.

It seems that the quieting of the train tracks has created much more favourable conditions in this habitat. The other elements of ideal amphibian habitat, such as shallow still water, heavy vegetation and shade, were already present in this area. The biggest factor that could theoretically keep amphibians from utilizing this habitat was the significant noise and vibration generated by the railway. When the noise had subsided for several weeks, the calls were heard. Approximately one week after the noise resumed, the calls ceased. It is unknown how a single adult amphibian ended up here. It is possible that a young amphibian had traveled through the riparian areas along Still Creek from another location. One potential source is Burnaby Lake, a much bigger and richer aquatic and wetland area located approximately 2 kilometers east of this site of observation, where amphibians are known to occur.

This observation shows an instance of natural resilience and adaptability, as well as interactions between economy and nature. Where amphibians were driven out of suitable habitat by anthropogenic noise, at least one individual began to resettle, weeks after noise subsided. It shows how natural systems are quick to adapt and re-establish themselves as soon as an opportunity permits. In contrast, it is hard to imagine a human system rebuild itself in any short amount of time. For example, as the global economy endures the currently ongoing disruptions, a period of recovery that is unlikely to take less than several years will occur. When activities that drive the human economy cease for just a few weeks, it can take a crippling toll that could require years to mitigate. However, nature might be severely hindered within a space for decades, but will quickly begin to return as soon as its pressures are lifted.