11 septiembre 2020
Habitat restoration and the positive impact on endangered species
The plants and animals native to the lands surrounding our operated assets are crucial to the health of local ecosystems as well as being culturally important to local communities, including Traditional Owners. We have a responsibility to minimise impacts to the environment during the life of our operated assets, and our ‘no net loss of biodiversity’ approach(1) underpins our work to rehabilitate the land and restore biodiversity during the life of our activities and after they have ceased.
In line with United Nations Sustainable Development Goals 14 and 15, BHP’s longer-term goal is that by FY2030 we will have made a measurable contribution to the conservation, restoration and sustainable use of marine and terrestrial ecosystems in all regions where we operate. We consult with local communities, scientific institutions and regulatory authorities to design fit-for-purpose habitat restoration programs across our operating regions.
In Australia, some examples of the measurable contribution we have made where our activities have ceased include: the artificial roosts and re-created native habitats we built in the Pilbara in Western Australia to encourage endangered animals to return to a closed mine site; the wetlands we restored to support the recovery of an endangered frog species in the Hunter Valley, New South Wales; and in southern Western Australia where we modified a post-mining landscape to support the return of four endangered plant species.
Bats and olive pythons in the Pilbara, Western Australia
BHP identified four significant fauna species during the planning phase for the Cattle Gorge iron ore mine in the northern Goldsworthy area of the Pilbara, which operated for seven years between 2005 and 2012.
The Ghost Bat (Credit: Carly Bishop)
Nationally threatened species the Pilbara leaf-nosed bat, ghost bat, northern quoll and Pilbara olive python are native to the local ranges, inhabiting cave structures, rocky habitats and waterholes. We used data from baseline habitat studies to incorporate restoration plans for these threatened species into the closure objectives for the site.
Closure of Cattle Gorge began in 2014 with the goal of returning the site to a native ecosystem used for pastoral activities. We incorporated an artificial roost within the pit area and re-created native habitats close to the entrances of nearby cave systems to provide hunting posts for ghost bats. We planted affected areas with vegetation from local seed mixes to restore habitats consistent with adjacent areas. We also placed rock piles within the rehabilitated areas to provide shelter for the northern quoll and Pilbara olive python, as well as their prey species.
Site monitoring has shown that ghost bats, Pilbara leaf-nosed bats and northern quolls and their prey species are using the rehabilitated areas, including the artificial roosts. It has also shown an increase in other animal species required to maintain the ecological function of the site. Ongoing studies at Cattle Gorge are planned to continue to inform closure strategies in the region.
Collecting Samples from a Ghost Bat (Credit: Biologic)
Cattle Gorge artificial roost (Credit: BHP)
Green and golden bell frogs in the Hunter region of New South Wales
In the Hunter region of New South Wales (NSW), BHP implemented environmental remediation and habitat restoration processes following the closure of the Newcastle Steelworks site in 1999 after 85 years of activity.
We launched the Hunter River Remediation Project in 2009 to remediate areas of the Hunter River affected by the activities of the steelworks, which included the construction of a lined emplacement facility to dispose of contaminated sediment that had been dredged and treated. The required footprint of this new facility extended into an area that had since been inhabited by green and golden bell frogs (Litoria aurea), a ground-dwelling tree frog native to eastern Australia and listed as an endangered species in NSW.
Litoria aurea captured within BHP habitat during nocturnal visual encounter survey. (Credit: University of Newcastle).
We worked with amphibian researchers at the University of Newcastle, an independent panel of experts with specialist experience in Litoria aurea ecology, and State and Commonwealth regulatory authorities to design and construct 2.6 hectares of breeding habitat (wetlands) on the nearby Ash Island within the Hunter Wetlands National Park to offset the area impacted during construction of the sediment emplacement facility.
Litoria aurea amplexus (mating) within BHP habitat during nocturnal visual encounter survey. (Credit: University of Newcastle).
We used data from scientific studies, including a captive breeding and translocation program and a five-year intensive research and monitoring program, to identify the primary threats to the species and design the new habitats to give them the greatest opportunity to flourish. For example, we built bunds (banks) around the wetlands to protect the frogs from predatory fish species during prolonged periods of wet weather, and designed deeper, permanent wetlands that connected with the water table to maximise water retention during the dry seasons.
The green and golden bell frog compensatory habitat project has made an important contribution to the conservation of this iconic endangered species. Since completion of the wetlands in 2016, the project has achieved success via the establishment of a breeding population, evidenced through monitoring and the recording of multiple breeding events in every subsequent breeding season.
Litoria aurea tadpole captured within BHP habitat and being measured during tadpole survey. (Credit: BHP).
Litoria aurea metamorph captured within BHP habitat during tadpole / metamorph survey. (Credit: BHP).
Rare plants at Beenup, Western Australia
Community consultation was central to the habitat restoration and closure strategy for BHP’s former Beenup Titanium Minerals Project, which operated between 1997 and 1999.
The Beenup project is located within the Southwest Botanical Province, a biodiversity hotspot in southern Western Australia, home to a variety of endangered plant species. Pre-mining, the land was used for cattle grazing, but in determining closure objectives, the community wanted to restore a significant proportion of the site to near-natural conditions while protecting the water quality of the Scott and Blackwood rivers.
We surveyed the post-mining landscape in detail to characterise the soils, hydrology and landform stability to develop a feasible design criteria for rehabilitation and habitat restoration. Ponds that had been dredged to depths of 55 metres were partially filled with material from dismantled tailings dams to create wetlands and other disturbed areas were landscaped to create dunes and plains to reflect the natural geomorphic features of the region. We then focused on tailoring specific revegetation programs using seeds that best matched each reconstructed landform, significantly reducing seed wastage and improving revegetation success. A small area was re-profiled to mimic the ironstone soil profile known to support rare and endangered flora species in the region.
Round-leaf honeysuckle planting and recording August 2019 (Credit: BHP).
Round-leaf honeysuckle planting and recording August 2019 (Credit: BHP).
In the 15 years since the rehabilitation works were completed, we have successfully restored 15 ecological communities and more than 250 plant species(2), including many conservation-listed species. The Beenup habitat restoration project continues to provide opportunities for research into rare and threatened plant species. In 2010, the Western Australian Botanic Gardens and Parks Authority used the site for a translocation study of four rare ironstone plant species that improved scientific understanding for their successful regeneration. In 2019, the Western Australian Department of Biodiversity, Conservation and Attractions planted a further 200 seedlings of one of these species, the nationally endangered round-leaf honeysuckle, to track survival rates.
Lambertia orbifolia subsp. Scott River Plains July 2005 (Credit: BHP).
Darwinia ferricola July 2005 (Credit: BHP).
Dryandra nivea subsp. Uliginosa July 2005 (Credit: BHP).
Grevillea brachystylis subsp. Australis July 2005 (Credit: BHP).
(2) Compared to a baseline of 293 species.
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