So you are probably wondering how weeding connects to climate change. Hang with me here, its a little complicated but I think I can connect the dots.
I went to a weed pull organized by our local and very awesome Weed Warriors group. We were pulling invasive scotch broom seedlings from a shoreline park. It was actually an incredibly heartening experience- two years ago, you could stand in the parking lot facing the ocean and not even see the water for this 5 to 7 ft tall massive scotch broom forest before you- this year, we were pullling tiny little seedlings that looked like grass blades, that was all that was left from our past efforts! Bad news: scotch broom has about a seedbank that can last 30 years or more, so we have our work cut out for us…
So how does scotch broom and other invasive plants connect to climate change? Well, climate change predictions impacting my corner of the world include sea level rise, and increased likelihood of extreme precipitation events. When we think about what these things might mean for our shorelines, it includes the possibility of shoreline loss, erosion and destabilization. For our streams, those streams that are not protected by intact streamside vegetation and soils that can hold water and attenuate runoff have a greater chance of scouring and sediment removal resulting from these events, which is not good news for our stream residents including invertebrate communities and spawning salmon.
How do invasive plants play into this mix? In many different ways depending on the plant. Vine-like plants, including kudzu in the south and English ivy here in the northwest can take over pretty much everything in its path, leading to some pretty scary monocultural landscapes and, at its worst, extensive loss of native forest cover. In the case of scotch broom, this plant can upend ecological succession. Scotch broom tends to invade open areas, and once it does, it tends to stick around, change soil chemistry, and not allow for other things to grow in, including trees. I also intensely dislike it because when flowering it gets my allergies going; speaking of which, there’s a lot of talk these days about another climate change connection, that of increasing temps= increasing growing period=extension of allergy season.
Its a bit more complicated to understand what the effects of scotch broom in the shoreline are or will be relative to climate change. Do scotch broom roots actually help hold down soils in the nearshore, and therefore, might they actually do some good in the face of increased storms and sea level rises? Possibly. But on the other hand, scotch broom in the shoreline means scotch broom in the uplands and in stream corridors, and that’s not good news for our native forests. I think I’d rather see our local beach grasses and other native veg doing their job in our waterfront areas. Plus, the native plants don’t get in the way of my view of the ocean, or make me sneeze.