Modelling processes and outputs
A range of tools and models can assist with the process of evaluating and creating habitat networks.
The output of most models will include some sort of map.
Landscape structure tools
These tools are used to analyse landscape structure, by evaluating the:
- physical characteristics of areas of habitat
- way in which habitat patches sit within the wider landscape
Areas can be allocated as core areas, potential movement routes and so on. The landscape is then assessed in terms of its overall structural connectivity.
Such tools can only assess whether there are physical connections between different features – that is, structural connectivity.
This analysis is sometimes called landscape characterisation or landscape metrics.
An example of a network based on this type of analysis is the Flemish Ecological Network.
Landscape function tools
Other tools and computer models assess the functional connectivity of a landscape.
This approach looks at more than just the physical linkages between core areas. It also explores the way in which the different parts of a landscape can be used by specific species.
By assessing the use and value of a landscape for different species, the positives and negatives of changes in land management can be assessed. Management decisions can then be made, based on which species you want to protect or encourage.
One landscape function model evaluates landscape connectivity for a specific focal species. Information is added to the model about:
- its requirements for habitat area
- its ability to disperse
- data about the landscape such as the location and distribution of core areas of habitat
Different land uses will have different permeability for the focal species. Real-world or estimated data about permeability lets you work out the ‘least cost pathway’ between one core area and another. This is the route that requires the least effort by an individual.
Such models can thus be used to identify obvious gaps between habitat areas or where movement between them is very difficult. These areas can then be targeted for habitat creation or changes in land management to create a more effective network. This may involve trade-offs between different species.
Landscape function tools include the:
- Forest Research BEETLE suite of tools
- Conefor software package
An example of this type of model is described in the forest habitat network case study.
Modelling green networks
Your model should address all social and economic as well as environmental objectives that you wish your green network to achieve.
You may need to work out how far people will walk in certain areas or where there are existing paths that they can use. You can then include this information in the network modelling and mapping process, to create a final network that meets a range of objectives.
See how habitat networks and people’s access to greenspace were modelled in the Urban Networks for People and Biodiversity project on the Sniffer website.
Different network models can produce various outputs, but most will give you some sort of map based information. You can then use this in a geographic information system, to display the mapping results alongside other relevant information.