Monitoring of invasive species

Technology group

Biodiversity monitoring is to observe and check the changes in the status and demographics of resources, species, habitats, or ecological communities. Monitoring provides a record to track trends in biodiversity over time and is carried out to reinforce knowledge of the ecological system, to raise public and political awareness of environmental issues and stimulate action through the reporting of these trends. A range of processes exert pressures on biodiversity. A key step in monitoring is to identify what these acting pressures are. Invasive species have been identified as a source of pressure by the International Union for Conservation of Nature (IUCN) and The Conservation Measures Partnership, who have categorized it among 12 other broad classes of pressures (including climate change, energy production & mining etc.). Non-native invasive species, such as insect pests and weeds, also have a huge impact on livelihoods, food production and biodiversity around the world. Monitoring of invasive species is therefore important for e.g. food security and conservation management decisions on local level, but also contribute towards assessments of national and international commitments. 

Responds to the following needs

  • Prevention of phenological changes
  • Ecosystem preservation
  • Food security

Suitable for

  • Natural environments with non-native species

Relevant CTCN Technical Assistance

  • Chile: Design of Biodiversity Monitoring Network in the context of Climate Change​

Relevant Technology Needs Assessment

Technologies & Methodologies

Biodiversity monitoring methods can be broadly split into field-based and remote sensing methods. Each method has its strengths and weaknesses, but the primary selection criterion is how realistic they are given limited resources. A phased approach is likely to be needed in many situations, starting with existing monitoring systems and available databases and gradually introducing more detailed methods when possible.

  • Animal trapping methods: Traps are mechanical devices used to capture animals. Live trapping techniques involve capturing animals for identification, measurement and tagging before being released.
  • Point and line transects: Survey walks recording animal sightings (seen or heard) and signs (e.g. spoor/nests/dung) are a common monitoring method in forest systems. Survey walks are used in two ways: reconnaissance survey (rapid assessment) or more systematic survey through the use of carefully positioned transects (straight trails). The distance of sightings and signs of both plants and animals are recorded from line transects or within/from fixed points. This is referred to as ‘distance sampling’ and allows for calculation of species density
  • Camera trapping: The use of camera-trapping as a survey tool for mediumto-large, and sometimes also small, terrestrial mammals and birds has become increasingly common over recent years and is a particularly suitable technique in forest habitats with significant advantages over alternative methods based on sign recognition. The survey method consists of remotely stationed motion and heat-sensitive cameras that take photographs or videos of passing animals. Technological advances have made camera trapping efective in recent years, and digital cameras are the standard, operating 24 hours a day. At night, infrared flash photography that is not visible to animals can be used to minimise startling the animals within the camera zone.
  • Bioacoustic surveys: Animal vocalizations often contain species-specific information that can be recorded and analyzed by experts, or using specialized equipment, analysis and classification software using species call librariess. This approach is particularly useful in visually restrictive habitats, such as dense forests, for vocalizing species.
  • Quadrats and plots: Quadrats and plots are commonly used methods for surveying plants, and can also be used to survey amphibians and reptiles and larger invertebrates that can be easily observed. Quadrats can be systematically placed (e.g. in a grid or along a transect to monitor changes in vegetation along an environmental or disturbance gradient) or randomly within the target habitat to record species within. Quadrats should be searched systematically from the outside edge to the middle. Species (or higher taxonomic groups) present, and percentage vegetation cover (e.g. using the Braun-Blanquet scale), within each quadrat are recorded.
  • Remote sensing: Remote sensing is any method of observing the Earth’s surface without being directly in contact with it. Information about the Earth’s surface is gathered using sensors on board aircraft or satellites to measure the electromagnetic radiation (or energy) reflected, scattered or emitted by the surface. Satellite data can provide valuable information on both the state of biodiversity (e.g. forest distribution, forest composition, primary productivity, phenology, and level of degradation and the pressures acting upon it

For more information see: A sourcebook of biodiversity monitoring for REDD+

Case studies