Phragmites performance tied to temperature and biotypes

TL;DR

Haslam examines how temperature affects growth and survival of the common reed Phragmites communis.
Seedling establishment, bud emergence, and growth timing depend strongly on temperature.
Temperature-adapted biotypes explain the plant's wide climatic range across habitats.

The story at a glance

Sylvia M. Haslam reports experimental findings on temperature effects on Phragmites communis Trin., a widespread wetland grass, in Annals of Botany volume 39 issue 4. The study links temperature to key life stages like seedling growth and bud development. It was published in 1975, building on prior work by Haslam on water and management factors.[[1]](https://academic.oup.com/aob/article-abstract/39/4/883/116542)

Key points

Wide distribution of Phragmites communis stems partly from biotypes physiologically suited to different climates.[[1]](https://academic.oup.com/aob/article-abstract/39/4/883/116542)
Temperature controls seedling establishment, bud emergence, and the timing of the growth cycle most directly.[[1]](https://academic.oup.com/aob/article-abstract/39/4/883/116542)
Shoot growth relies on temperature; high enough temperatures allow fast seedling growth to escape competition, drought, or flooding.[[2]](https://www.jstor.org/stable/42758557)
Experiments used controlled cooling/heating of water and soil to test effects across flooded and non-flooded conditions.
Burning, frosting, or early soil warming can shift growth timing by influencing temperature.
Growth performs best at 20-30°C; germination and emergence occur from -2 to 8°C, but suppress above 30°C.[[3]](https://pmc.ncbi.nlm.nih.gov/articles/PMC5715336)

Details and context

The article details lab and field-like tests on young plants and rhizomes, focusing on how temperature variations mimic climates from cool temperate to warmer regions. For instance, cooling water evenings simulated northern conditions, slowing growth, while warmer setups sped it up.

Phragmites communis (now often P. australis) forms dense wetland stands; prior Haslam papers (1970 on water supply, 1971 on community regulation) show temperature interacts with water levels and competition.

Biotypes from different origins respond variably, aiding invasion in varied habitats like marshes and lake edges.

Key quotes

None reliably sourced from the original article.

Why it matters

Temperature shapes Phragmites spread in changing climates and wetlands, influencing stand density and competition. Wetland managers and ecologists can use these insights for predicting growth in restored or fluctuating sites. Watch local biotype responses to warming, though full experiments are needed for specifics.[[4]](https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2745.12797)