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Rot Squad - Project Backgrounder

What the Rot Squad?

The goal of this project is to crowd-source data on rot rate in headwater streams across different land uses in southern York Region such as residential, agricultural and industrial. With your help, we will be able to determine if the rot rate of cotton strips is a successful proxy measure for stream health. If successful, we will be able to provide data for larger evidence-based decisions models on land-use planning, and ultimately informing and improving land use decisions.

Why Rot?

Rot or decomposition is a key ecosystem process. Measuring ecosystem processes can help us to understand and compare how different ecosystems function. When materials fall into streams, they undergo a process called decomposition, where nutrients are recycled back into the plants and animals that make up complex and diverse food webs. The rate of decomposition can be an indicator of ecosystem health and be influenced by a variety of stressors (e.g., temperature and chemical pollution).

Traditionally, it is measured using leaf litter (before and after biomass). Leading edge scientists are now using cotton strips, measuring the loss of its tensile strength to determine rot rate.

To learn more about the use of cotton strips to measure rot rate, check out these journal articles:

  1. A standardized cotton-strip assay for measuring organic-matter decomposition in streams
  2. Organic-matter decomposition along a temperature gradient in a forested headwater stream

Why headwater streams?

Headwater streams are small but important streams in any watershed (shown as 1 in the image below). They make up the majority of stream length in a watershed (>50% to 80%) and provide fish habitat. They also provide important downstream sources such as nutrients, organic material and sediment. However, it is not well known how different land uses affect this delivery and the resilience of downstream ecosystems. Headwater streams are less visible and currently from a planning perspective, are considered less important than larger fishable/navigable waters. In addition, headwater streams are being altered or are lost due to urbanization.


This project is generously supported by the Ontario Trillium Foundation with in-kind support from the University of British Colombia and the Toronto and Region Conservation Authority.

Ontario Trillium Foundation Logo Univesity of British Colombia Logo