Large-Scale Chemical Control of Smooth Cordgrass (Spartina alterniflora) in Willapa Bay, WA: Towards Eradication and Ecological Restoration

Abstract

The grass species Spartina alterniflora (smooth cordgrass) is an invasive ecosystem engineer with serious ecological consequences to intertidal mudflats and saltmarshes. The largest infestation in North America was in Willapa Bay, WA, where it occupied ~3,600 solid ha, covering ~27,000 ha of intertidal habitat. An extensive effort by land managers to eradicate S. alterniflora has been in place for over two decades. This article discusses (1) the success of the control and issues that will need to be resolved in order to achieve eradication; (2) post-control succession of affected tidelands to native marsh species, and (3) the impact that S. alterniflora removal has had on shorebird usage of affected tidelands.

Peer Review #1 of "Effects of mechanical and chemical control on invasive Spartina alterniflora in the Yellow River Delta, China (v0.1)"

“…The cost of controlling Spartina alterniflora is very high. The mean annual cost to manage Willapa S. alterniflora during five years was ~$3,500 km -1 of shoreline per year (Patten et al 2017). The cost of chemical control in this study was 1067 dollars per hectare.…”

“…Chemical control methods usually use herbicides, which are easy to implement and have achieved good control effect in some areas. However, herbicides may cause environmental pollution and damage the health of animals and plants (Patten et al 2017;Qiao et al 2019). Biological control methods need to be improved, and there is also a risk of ecological invasion of new alien species (Xie et al 2018).…”

“…3) It takes too long to eliminate or eradicate S. alterniflora, ranging from a few years to more than a decade (Kerr et al 2016;Patten 2004;Patten et al 2017;Riddin et al 2016). The drawbacks of the control approaches may be due to the various growth periods of S. alterniflora or environmental conditions, such as climate, topography, and elevation.…”

Effects of mechanical and chemical control on invasive Spartina alterniflora in the Yellow River Delta, China

“…Chemical control methods usually use herbicides, which are easy to implement and have achieved good control effect in some areas. However, herbicides may cause environmental pollution and damage the health of animals and plants (Patten, O’Casey & Metzger, 2017; Qiao et al, 2019). Biological control methods need to be improved, and there is also a risk of ecological invasion of new alien species (Xie et al, 2018).…”

“…Although some of the previous approaches can achieve good control results, there are still many aspects to be improved: (1) The control efficacy of an approach may vary greatly in different regions (Patten, 2004); (2) the cost of control needs to be further reduced (Riddin, van Wyk & Adams, 2016; Yuan et al, 2011); (3) it takes too long to eliminate or eradicate Spartina alterniflora , ranging from a few years to more than a decade (Kerr et al, 2016; Patten, 2004; Patten, O’Casey & Metzger, 2017; Riddin, van Wyk & Adams, 2016). The drawbacks of the control approaches may be due to the various growth periods of Spartina alterniflora or environmental conditions, such as climate, topography and elevation.…”