Macroecology is the study of large-scale patterns and processes in biodiversity around the globe. One of the key aims in macroecology is to explain the processes that give rise to the patterns observed. Of course, the patterns of species distribution need to be known in the first place, before we can ask why they occur. Traditional ecological surveys have provided us with invaluable information regarding the distribution of thousands of species, however, when it comes to the more cryptic and far-ranging species, radio tracking technology is allowing us to observe species distribution patterns we would have otherwise not known. With the current rate of global habitat loss and species extinction, we need to keep tabs on where species are occurring in the world and why. We need basic distribution data for species in order to undertake all other aspects of ecological research and to implement conservation efforts effectively.
Radio tracking devices have been designed to attach to a variety of taxa including birds, amphibians, invertebrate, reptiles, fish and mammals and the information gained about the species’ ecology can be vast. Every time a researcher locates an animal they gain a piece of information showing that a specific individual is at a certain place at a certain time. Frequent location data throughout the day or night, provides an excellent insight into the animals’ daily movement patterns, and can allow the observer to know where an animal started and ended its travels each day. Less frequent location data over a longer period can provide data on an individual’s home range. When similar data is collected from several individuals in a population, information is gained on the spatial ecology of the species. Further, if the location data is accurate and habitat information is available then habitat selection by a species in a given area can be studied. This information can be invaluable for conservation action; prioritising the protection and restoration of the most important habitats for the benefit of a species.
Animal migrations are some of the most spectacular natural events on earth and radio tracking has revealed much information about these journeys. The time and location data can reveal information on migration triggering conditions, migratory paths, duration, weather, altitude and seasonal ranges. By observing the intensity with which an animal is using certain parts of its range, we can examine the reasons why. Perhaps in carnivores there is an abundance of prey in a certain area or for herbivores better habitat or forage. The effects of climate change on species migrations can be observed from radio tracking data. Over the past 30 years in Oxfordshire, UK, the average arrival and departure dates of 20 migratory bird species have both advanced by eight days. It was found that the timing of arrival has advanced in relation to increasing winter temperatures in sub-Saharan Africa, whereas the timing of departure has advanced after elevated summer temperatures in Oxfordshire. It is such that radio tracking data from migratory species can provide a long-term indicator of the direct effects of climate change upon animal species. The continuation of these studies may reveal the abilities of species to adapt to the effects of climate change in the future with regards to changes in their spatial ecology and migratory activity patterns.
Behavioural information about an individual, for example whether it is moving or not, can be gained by simply observing the variation of a signal. However, additional sensors can now be fitted to radio tracking devices. Posture and activity sensors utilise a mercury tilt switch which changes the signals pulse rate depending on the position of the device. Fitted to birds, for example, this can provide information on whether they are perched or flying. Temperature sensors can be used to measure ambient temperature or body temperature depending on where they are mounted on the device. Measuring ambient temperature can reveal, for example, when a small mammal is in its nest or outside foraging and measuring body temperature can reveal when an individual is hibernating or has died.
Radio tracking provides an individual’s location at a certain time, but to a scientist, it provides an opportunity to exercise their ecological knowledge on a living case study.