Soil Seedbank Dynamics and Species Diversity in Pimelea-Infested Paddocks Under Pasture and Cultivated Conditions

TL;DR

This study shows that pasture lands support more plant diversity than cultivated lands, while cultivated areas have more riceflower seeds, suggesting farming practices affect plant ecosystems.

Contribution

The study provides new insights into how land use and soil depth influence riceflower seedbanks and plant diversity in western Queensland.

Findings

Pasture paddocks had higher species diversity in topsoil compared to cultivated paddocks.

Cultivated paddocks showed a significant increase in riceflower seed counts over two years.

Seed distribution and diversity varied with soil depth, site, and climate conditions.

Abstract

This study looked at how pasture and cultivated lands in western Queensland impact riceflower spread and plant diversity. Researchers found that pasture areas tended to support a greater variety of plant species, especially near the soil surface, while cultivated lands had more riceflower seeds, mostly deeper in the soil. This difference suggests that farming practices, which disturb the soil, may encourage riceflower growth but reduce other plant diversity. Seed distribution also changed with climate conditions from year to year, highlighting the need to consider weather patterns in planning land use. By understanding these patterns, farmers and land managers can adopt practices that help control riceflower while preserving soil health and plant diversity. These findings emphasize the importance of sustainable land management practices that balance agricultural productivity with ecosystem preservation. Ultimately, this research provides valuable insights for developing effective land use strategies that benefit both the environment and local communities by supporting resilient, diverse ecosystems.

Pasture lands, while appearing uniform in species diversity, exhibit notable variations upon closer examination. The study on Pimelea (or riceflower) seedbank dynamics revealed significant variations in seed density and distribution across soil depths, sites, years, and between pasture and cultivated paddocks in the same region of western Queensland. For the total number of germinable riceflower seeds across both the years 2019 and 2020, there is a clear distinction between pasture and cultivated paddocks. Pasture paddocks exhibited a gradual increase in total seed count from 108 seeds m−2 in 2019 to 121 seeds m−2 in 2020, resulting in a combined total of 229 seeds m−2 over the 2 years across both depths. In contrast, cultivated paddocks showed a more substantial increase, with seed counts rising from 146 seeds m−2 in 2019 to 255 seeds m−2 in 2020, resulting in a combined total of 401 seeds m−2 across both depths. Additionally, the Shannon–Wiener index at Site 1 indicated increased species diversity in the topsoil of pasture paddocks in 2020 compared to 2019, while deeper soil diversity decreased. Cultivated paddocks showed a declining trend, while pasture sites exhibited stable or increasing diversity. Pasture management generally maintained or enhanced diversity better than cultivation, especially in the topsoil layer. These findings highlight site-specific differences influenced by soil properties, land management practices, and local environmental conditions, shaping riceflower seedbank dynamics. Understanding these patterns is crucial for developing targeted management strategies to control riceflower in affected areas. Long-term field studies focusing on seedbanks are essential to develop sustainable control strategies.

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