The ecological and biodiversity conservation values of farm dams: A systematic review

RESEARCH ARTICLE The ecological and biodiversity conservation values of farm dams: A systematic review Michelle LittlefairID1*, Ben C. Scheele1, Martin Westgate1,2, David Lindenmayer1 1 Sustainable Farms, Fenner School of Environment & Society, The Australian National University, Acton, Australian Capital Territory, Australia, 2 Atlas of Living Australia, Commonwealth Scientific and Industrial Research Organisation, Black Mountain, Canberra, Australian Capital Territory, Australia * michelle.littlefair@anu.edu.au Abstract Biodiversity is in rapid decline globally with agriculture being one of the leading causes. Within agricultural landscapes, some features provide a benefit to biodiversity that is dispro- portionate to their spatial area. An interesting example is artificial ponds–or farm dams– which can support a large variety of taxa. Here, we present a global review of farm dam research related to biodiversity conservation objectives to provide an overview of the topics, key research insights, and the characteristics of current research. We used a three-stage process to screen literature and identified 104 relevant papers across 27 countries encom- passing studies of 13 different taxa. Most of the studies were short-term (less than 5 years) with small sample sizes (less than 20 sites). Of the 104 papers, 88 were focussed primarily on ecological outcomes, such as species richness or abundance, and 15 on primary produc- tion outcomes, such as crop and livestock yield, despite addressing or measuring ecological

metrics. Only one study measured both ecological and primary production outcomes. Stud- ies frequently examined how the features of dams (79 studies) and attributes of the sur- rounding landscape (47 studies) impact particular species and communities. Terrestrial mammals (1 study) were under-represented in the literature with macrophytes (28 studies), macroinvertebrates (26 studies), and amphibians (19 studies) receiving the most attention. Our results reveal a growing trend towards recognizing farm dams as habitats for various taxa, including amphibians, beetles, dragonflies, and other macroinvertebrates within agri- cultural environments. Significant knowledge gaps exist in understanding how dam age, invasive species, and effective management practices impact the biodiversity conservation values of farm dams. Future research should emphasize enhancing biodiversity by collabo- rating with landholders to increase habitat through strategic vegetation planning, minimizing runoff and nutrient inflow, and restricting stock access. 1. Introduction Major declines in biodiversity are occurring across the globe [1,2] as a result of the intensifica- tion of agriculture [3,4], land clearing [3], use of chemicals [5], and the rise in invasive species adapted to modified landscapes [6]. These factors have resulted in substantial declines in groups such as amphibians [7], birds [8] and invertebrates [9]. The persistence of biodiversity PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0303504 May 13, 2024 1 / 18 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111

OPEN ACCESS Citation: Littlefair M, Scheele BC, Westgate M, Lindenmayer D (2024) The ecological and biodiversity conservation values of farm dams: A systematic review. PLoS ONE 19(5): e0303504. https://doi.org/10.1371/journal.pone.0303504 Editor: Petr Heneberg, Charles University, CZECH REPUBLIC Received: September 25, 2023 Accepted: April 25, 2024 Published: May 13, 2024 Copyright: © 2024 Littlefair et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The detailed data cannot be shared within the manuscript due to its vast size. However, the data and articles analyzed are available in supporting information (Appendix 2). Data breakdowns and codes are accessible from Michelle Littlefair (contact via michelle. littlefair@anu.edu.au) for researchers who meet the criteria for accessing confidential data. Funding: The author(s) received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist.