The Relationship of Habitat and Biodiversity on Agricultural Land
Biodiversity is a term used to refer to the amount of living organisms found in any given area. Higher numbers of living organisms (types of species and their abundances) i.e., biodiversity, indicate a healthier landscape. Due to the nature of most living organisms, it can be challenging to measure their abundance. Unlike most other living organisms, bird species richness (different types of species) and abundance can be observed and measured by most people with some small degree of skill. Different birds occupy different habitats in different seasons and different times of the diurnal cycle. Birds are typically easy to observe with a pair of binoculars and a field guide to the local bird species. Birdwatchers with a high degree of skill or “Twitchers” are often able to identify and count birds by their calls. In healthy landscapes, seed eater, foliage grazer, insectivore, nectivore, omnivore, and carnivore birds can represent the full range of trophic levels. Changes in land use and management affect shelter, food, and habitat resources available to birds. Collectively, these characteristics of birds make birds an excellent practical indicator to monitor and report the health of biodiversity on the property.
Suberp Fairy Wren. Photo: Belinda Wilson
Biodiversity plays a vital role in helping decision-makers to understand the ecological function, structure, and composition of ecosystems of land use types, including regenerative agriculture. Regenerative land managers often use birds as an indicator of ecosystem condition to assess the effects of land management practices on agricultural landscapes. Being able to observe changes in biodiversity, before and after adopting regenerative land management practices, can provide land managers with support and validation of whether what they are doing is working.
The Marsh family are leading figures in Australian regenerative agriculture. Since 2000 the family has supported ongoing bird surveys on their property near Boorowa NSW. Researchers from Greening Australia conducted the studies. Richard Thackway compiled and analysed the data. In 1980 3% (20.6 ha) of the Marsh’s property was covered by native vegetation trees and shrubs. In 2012 that coverage had increased to 20% (82.4 ha) of the property. The progressive increases in the extent of trees and shrubs occurred because of the Marsh’s investment in revegetation on the property.
Greening Australia conducted the bird surveys at three sites, two located within revegetated areas and one location in a grazing paddock without revegetation. In 2000 an average of 7 species of birds were observed in the revegetated places, and by 2017 this number had increased to 19 (Figure 1).
Figure 1. Extent of trees and shrubs compared to the numbers of bird species (Richard Thackway).
The increase in bird species observed on the Marsh’s property coincided with the expansion and development of the revegetated areas. As the revegetation aged, these areas provided resources for different bird species, including; shelter, habitat, nest sites, and food. If these resources are not present in the landscape, selected species will not occur in an area, for example, the Superb Fairy Wren (Malurus cyaneus) requires a habitat of dense cover and low shrubs.
Bryan Ward is a Soils for Life case-study land manager. Bryan utilises birds as an indicator of biodiversity and landscape health. Investing in direct-drill seeding of native plant trees and shrubs species across much of his property resulted in improved habitat and resources for birds on his farm near Albury, NSW. Local ecologist Ian Davidson conducted a survey of birds in 2018. Ian found that the number of bird species on Illawong greatly exceeded the numbers found on nearby properties. Neighbouring farms had not invested in revegetation activities.
The improvements in biodiversity observed on the Marsh and Ward properties are the results of their regenerative landscape management activities in an agricultural setting. By improving the extent and condition of native vegetation, both land managers improved the health of their landscapes.
Both the Marsh family and Bryan Ward manage their rural properties primarily for beef cattle production and have gained significant personal satisfaction by improving the biodiversity on their farms. Land managers who enable and promote enhancements in biodiversity receive multiple benefits. Enabling researchers to conduct standardised bird surveys in space and time, on their properties can lead to a sense of achievement for land managers. The aesthetics of a visually appealing landscape are a boon to farm managers and visitors alike. Farming families can enjoy the seasonal and annual cycles that result from enhancing the local biodiversity. Biodiversity brings improved social health and wellbeing; and contributes to the health of the local and regional landscapes.
Greg Hosking is an ecologist. Honorary Associate Professor Richard Thackway is a Research Scientist. Both Greg and Richard are members of the Soils for Life team.