Science for Saving Species Research Findings Factsheet Project 4.4

Science for Saving Species Research findings factsheet Project 4.4 Persistence through tough times: Fixed and shifting refuges in threatened species conservation In brief Unburnt landscapes as shifting refuges Refuges are vital to the conservation But sometimes the most vital Patches of vegetation that have of Australia’s threatened species. refuges shift across the landscape. remained unburned for many years – They are places that species may This makes sense when you consider sometimes decades – can be important retreat to during tough times, until that Australia is a vast land of refuges for many species living in conditions ease and they can expand droughts, flooding rains and highly the arid and semi-arid zones. once more into their range. Refuges variable weather. Refuges can also can work either by reducing the shift for reasons of becoming the Many native birds, mammals and intensity of stressors like drought, last place where an animal can reptiles are more vulnerable to fire, heatwaves or disease, or by avoid a predator or a disease. predation in recently burnt areas, providing safety from predators and as cats are highly efficient hunters Australia’s national parks and reserves other enemies. This may be for a day in places where most of the vegetation often capture these important or a week, or for years, decades and cover has been burnt away. places. However, our research even centuries. Understanding where For example, endangered birds shows that the often-shifting nature refuges are, and how to protect such as the mallee emu-wren of refuges means we need to also or even create them is therefore (Stipiturus mallee), Carpentarian think about places in the broader essential if we are to prevent grasswren (Amytornis dorotheae) and landscape that will help threatened extinctions of imperilled species. night parrot (Pezoporus occidentalis) species survive now and into the all depend on hummocks of spinifex Some refuges are easy to identify, future, and how to promote them. grass that have remained long unburnt. such as an artesian spring that We also need to recognise when helps animals in an arid landscape refuges alone are not enough Likewise, the great desert skink survive a drought. to protect species. (Liopholis kintorei) and the sandhill dunnart (Sminthopsis psammophila) Roosting habitat for night parrots - old unburnt spinifex. Photo: Nick Leseberg need patches of unburned spinifex to escape predation by feral cats. In some cases, structural characteristics – like rocks – protect these spinifex patches from fire, and in other cases temporary factors like wind direction determine which areas are burned and which are left unburned, so that the location of unburned patches can change over time. Understanding the problem Our findings Refuges are likely to be crucial to the This definition helps us to We found that, in Australian persistence of some of our threatened differentiate refuges from remnants, conditions, refuges often provide species. This is particularly so when which are places where species greater vegetation cover, water, food species extinction rates in our times have always persisted in an availability, protection from predators or are estimated to be a thousand times undisturbed way, and from some combination of these, than what above what we might otherwise havens, which are places where could be found in the wider landscape. expect, due to threats created by predators have been excluded, We identified that refuges arise in two human activity – chiefly, land clearing, such as fenced exclosures. ways through dynamic and shifting changes in land use such as fire Most previous research has processes – patchiness and buffering. regimes, and introduced species. focused on refuges that are in fixed Patchiness refers to the distribution and The research team began by places, but there is an increasing intensity of the stressor across space. synthesising current knowledge of understanding of the importance of This is particularly the case with “press” the role of fixed and shifting refuges refuges that shift over time across stressors, which are persistent, such for Australian threatened species. the landscape. Studying this kind of as urbanisation, and “pulse” stressors, We examined the role of these refuge is more difficult, but vital if which are sudden, such as flood and refuges in protecting species against we want to enhance or create them fire. Less affected patches, such as stressors like drought, fire, heatwaves, to benefit threatened species. For mountains, gorges or rocky areas, introduced species, disease, and the example, while Australia’s nature can act as refuges until more severely interactions between them. conservation and Indigenous affected areas can recover. Protected Areas cover 23% of We define a “refuge” as a place Australia’s land, habitats outside Buffering refers to areas that are that offers individuals or populations these protected areas are likely exposed to a disturbance, but have of species relief from stressors to become essential to helping properties that lessen the impact of the over time or in space. species to survive tough times. stressor on an individual or a population. For example, gullies can provide refuges for bird species during and after fires What we did when the surrounding habitat is burned. Buffering also provides important refuge Experts from across Australia with often affect species in interacting from stressors that build gradually specialised knowledge about ways, making them difficult to tease over time, such as droughts, when different ecosystems and kinds of apart and treat separately. the availability of water at riverbanks animals were brought together for becomes vital for many species. The research team considered this project. We synthesised the refuges in terms of a species’ niche: Toxic plants, including the Gastrolobium nature and functioning of the various that is, a location (in time and space) genus, can create refuges for native types of refuges, using examples where the animal’s needs are met. wildlife from exotic predators without from diverse environments (e.g., As these places can change over time, evolved tolerance to the toxins. arid zone, woodlands, tropical a species may need to move between Many of these toxic plants respond rainforests), stressors (e.g., drought, favourable locations to stay within to fire or other disturbance and hence fire, heatwaves, introduced their niche. A refuge, then, is where the efficacy of these refuges can predators and competitors, disease) an individual’s or a population’s niche potentially be improved by informed and species (e.g., birds, reptiles, will persist even if other parts of their land management. mammals, frogs and fish). Our study range become inhospitable. recognised that multiple stressors Refuges can also arise through species interactions, such as predator Kowari in Sturt Stony Desert Photo: Cat Lynch suppression, where the presence of dingoes can create a refuge by suppressing the impact of smaller predators such as cats and foxes. Such refuges can be quite dynamic over space and time, and can have very short time-scales, even hours, such as when cats shift their hunting behaviour to avoid times of peak dingo activity. Shifting refuges are -- by their nature -- harder to locate than fixed ones. However, we can narrow the search by identifying landscape features within a species’ range or places within it where predator populations occur. Methods such as topographical mapping and remotely sensed data can help find these places. Understanding these mechanisms by which species benefit from refuges can help guide scientists and land managers to create new or artificial refuges. For example, if individuals or populations of a species use a refuge because they can access food there more easily Little bittern. Photo: Luc Hoogenstein CC BY-SA 4.0 Wikimedia Commons with lower risks of predation, then management options to explore Recommendations The whats, wheres and whens might be either how access to food can be enhanced, or the Key refuges for Australia’s threatened To maximise the success of risk of predation lowered, or both. species need to be located and management of refuges, the following protected from habitat loss, for questions need to be considered: example, through urban development. what action is needed, where it is We also need to ensure that they are needed and when it is needed. Refuges for our times not further impacted by other threats. Shifting refuges are by their very of climate change From a management perspective, it is nature more difficult to incorporate important to understand how individual In late 2018, bird watchers and into protected areas and management species use refuges. In particular, plans. However, broad-scale scientists alike were surprised the impact of multiple stressors that to find rare little bitterns management actions such as interact must be taken into account: protecting top predators (i.e., dingoes) (Ixobrychus minutus) at as we have seen, effective refuges Bool Lagoon in South Australia, and preserving vegetation cover in frequently provide relief from more reserves may help to promote shifting which is well outside their usual than one stressor at a time. range. The birds were believed refuges throughout the landscape, to be using Bool Lagoon as a While some kinds of refuge are likely with the exact location of these driven drought refuge due to the very to be well-represented in parks and by more dynamic processes, such as dry

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