Looking at the big picture: General Landscape Connectivity Model
Travel across landscapes is integral to most plant and animal life cycles. Animals move in search of food, shelter, mates or in response to weather events. Likewise, the survival of many plant species often depends on the ability of their pollen and seeds to move. Increasingly, we are seeing movement in response to changing climate.
Habitat connectivity refers to how and to what degree distinct patches of habitat are connected, which can influence the distribution, genetic diversity, and health of animal and plant populations.
Traditionally, most of our conservation efforts have been focused on a local scale. For example, we might protect a particular river ecosystem, or a section of bushland in a national park.
However, it’s also important to look at how these different habitats are connected, and how this enables species to move around more easily, rather than considering habitats in isolation.
So how do we make sure that we are looking at the big picture across multiple local habitats?
Pathways for habitat connectivity
Modelling habitat connectivity can be challenging. Some models are too simplistic: they may only consider the distance between a patch of habitat and its nearest neighbour, or don’t consider the nature of the areas between patches, or they fail to consider connectivity within patches of habitat. They might be impractical due to the vast number of calculations needed for them to work, or it may be too difficult to neatly classify areas into ‘habitat’ or ‘non-habitat’.
The General Landscape Connectivity Model is unique in its combination of scale and detail to evaluate habitat connectivity. The model uses multiple pieces of satellite evidence to evaluate the health of areas – for example, by looking at the canopy cover and the stability of ground cover. This model incorporates the movement abilities and patterns of specific species to show the availability of corridors or stepping stones in between areas of habitat.
‘A typical woodland bird will only fly over cleared areas for 100 m, maximum. Traversing cleared areas, with little food, shelter and cover from predators, can be costly. So, they will choose to go over healthy areas. This is what scientists call the “least cost path” – which refers to journeys or paths organisms are more likely to attempt and which are more likely to succeed,’ said Michael Drielsma, principal scientist from the metrics and forecasting team in the Department of Climate Change, Energy, the Environment and Water.
Working collaboratively to develop a powerful tool
The General Landscape Connectivity Model is the result of 10 years of collaboration between modelling experts from the department, CSIRO and the University of New England. Their combined expertise delivered this simple and sophisticated tool, which sought to address many of the limitations of existing models.
‘We get information from every 90 x 90 m [patch of land] across the state. No one has done anything like it. We have built on a robust body of work modelling connectivity, but never at a resolution this fine,’ said Michael.
Over the next 2 years the team at the department will develop a climate-informed version of this model. Instead of just mapping linkages across space, this revised model will map linkages across time, to reflect the impacts of climate change. The team is also partnering with the University of New England to map how climate change affects koala migration pathways.
Think regional, act local
Reliable modelling that looks at our whole state is key to informing policy and efforts at the state and local scales.
The model is used for assessments as part of the Biodiversity Indicator Program. Local Land Services and the Biodiversity Conservation Trust leverage the tool for local land conservation efforts.
The full peer-reviewed research paper is freely available at Science Direct.
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