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Field Observations – Matthew Peterson
The area I have chosen for this study is Pipers Lagoon, located in Nanaimo B.C. I visited the area on January 9th at approximately 9:40 am. The weather was mainly cloudy with a few sunny breaks, ~4 degrees in temperature, and fairly windy. Low tide in this area had occurred at 7:39 am.
The entire park area is approximately 8 hectares in size and consists of a tidal mudflat (the lagoon), an approximately 300m long tombolo or sandy isthmus, and a rocky headland or tied island. It is a well-visited site year-round, with a somewhat rugged trail system that loops the entire tied island. Elevation change is approximately 20m (according to alltrails.com) between sea level at the tombolo and the high point on the tied island.
The tombolo which has a relatively flat topography and predominantly grassy vegetation connects the mainland Vancouver Island with the rocky headland or tied island. The eastern side of the tombolo is exposed to the open ocean, consists of an abundance of dunegrass, and has a predominantly pebble-sized substrate. The Western side which is exposed to the lagoon waters generally lacks dunegrass but has an abundance of various other smaller-sized grasses and has a much smaller and finer substrate.
Figure 1: Looking North Towards Tied Island Along Tombolo
The lagoon itself undergoes daily tidal fluctuations but was pretty well entirely underwater when I arrived. The tied island which is approximately 5 hectares in size consists of multiple rocky outcrops where various lichen, moss, and broad-leaved stonecrop were observed. The smaller rocky outcrop was dominated by mainly Garry Oak, with a couple small arbutus also observed. The main tied island had a variety of vegetation including Ocean Spray, Nootka Rose, and the invasives Spurge-Laural and English Ivy. Tree species observed here were Douglas Fir, Garry Oak, and Arbutus. The northern, exposed portion of the tied island was dominated by Douglas Fir, while the south-facing side formed a typical Garry Oak ecosystem, with Camas known to bloom here in the Spring.
Figure 2: Garry Oak and Douglas Fir on Tied Island
The area is well known for birding and I was fortunate to observe several species including Mallard, Bufflehead, Glaucous-Winged Gull, Bald Eagle, White-Crowned Sparrow, Black Turnstone, and a Varied Thrush.
Figure 3: Varied Thrush in Garry Oak
Potential Study Questions
Based on my initial field observations here are three questions that may form the basis of my study.
Question 1: Does exposure to salt spray determine the abundance and distribution of the Broad-Leaved Stonecrop?
It was noted that the stonecrop was generally found along bluffs exposed to the ocean as opposed to the lagoon.
Question 2: Does the difference in substrate composition of the lagoon compared to the beach (on the other side of the tombolo) impact species diversity?
Although the tide was up fairly high I imagine the species diversity between the lagoon and the beach area must be at least somewhat impacted by the substrate.
Question 3: Do the tree species composition and diversity change from mid tied island to the perimeter with sun exposure?
It was noted that the majority of Garry Oak on the tied Island were concentrated on the more southern facing side, while the Douglas Fir was denser in the north direction.
Field Notes:
