Ecological connectivity represents the degree to which the landscape facilitates or impedes movement of species. This question is crucial for preventing local extinctions, thereby playing a vital role in biodiversity conservation.
Promoting ecological connectivity fosters multispecies justice by ensuring non-human species have the necessary habitats and corridors to thrive – also in the midst of human activity.
The Monash University Indonesia team, in collaboration with the Finnish Environment Institute, Syke, has undertaken preliminary modelling of ecological connectivity for Tangerang Selatan, a peri-urban area on the outskirts of Jakarta, the capital of Indonesia.
Tangerang Selatan is home to 1,354,350 people. The area is currently experiencing significant development: rural peri-urban landscapes are being urbanised, driven by private sector construction of commercial and residential properties including high-rise apartments. This development increases the fragmentation of the natural environments, endangering the habitats of the non-human inhabitants of the region.
An important first milestone in the project was recently achieved as we finalised the first outputs of the connectivity model identifying livable environments and their connections. We identified critical green patches of urban biodiversity for two groups of species: small arboreal and medium sized terrestrial mammals. We also identified ‘least cost paths’, or optimal pathways between habitat patches for animal inhabitants: these are indicated in red lines in the figures below. These pathways represent locations species are most likely to use when moving through the urban environment.
The figure below illustrates the results of our connectivity analysis for a) small arboreal mammals (with a maximum crossing distance between two patches of 250 m) and b) medium sized terrestrial mammals (5000 m). Pinch points within the Least-Cost (LC) corridors represent areas where movement is highly constrained. These areas represent good locations to target conservation activities that support movement such as ecological restoration. The inset illustrates how connectivity for small arboreal mammals only exists to a small extent, meaning that they need a landscape with suitable habitat patches close to each other. Inset 1 indicates that there is connectivity between patches, while inset 2 indicates no connectivity.
The third figure below shows a visualisation of connectivity between habitat patches. Small arboreal species make use of patches larger than 5 hectares (dark green) and medium-sized terrestrial species use patches larger than 100 hectares (light green). The size of the purple circles illustrates the modelled importance of a patch, and the strength of the black lines describes the importance of a connection between patches. The red lines describe the identified optimal (Least-Cost) paths between the patches where animals are most likely to be found moving through the landscape.
The analysis shows how the landscape is fragmented based on the component boundaries that describe which patches are connected to each other and isolated from each connected group of patches. The results show that, from the perspectives of small arboreal and medium sized terrestrial mammals on the landscape are very different from each other. For example, for small mammals, the landscape appears highly fragmented, with many isolated patches, while for medium sized mammals there are possibilities to move across the whole and every patch is connected. This is mainly due to differences in movement, as medium sized terrestrial mammals have much longer dispersal distances than small mammals.
Recognizing the role of green space as connectors of habitat patches for other species than humans means that it is necessary to conserve and protect such habitat from further loss due to urban development. Enhancing connectivity between critical patches for urban species can offer substantial benefits to city residents through providing a biodiverse and green city, which bring aesthetical, recreational, health and other benefits from the many ecosystem services that a thriving nature provides.
For more information about this sub-project, please contact Risty Khoirunisa risty.khoirunisa@monash.edu.
Text: Risty Khoirunisa, Monash University, Indonesia
PhD Student, the MUST research project
