CONSIDER
Conservation of Soil Organism Diversity under Global Change
CONSIDERConservation of Soil Organism Diversity under Global Change |
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In CONSIDER, we are investigating the extent to which human activities threaten soil biodiversity and how this in turn may influence the functioning of entire ecosystems. We are assessing soil biodiversity in relation to land abandonment, habitat fragmentation, farming and climate change and showing how appropriate management measures can be developed to restore or sustain soil biodiversity.
As well as being important in soil processes, soil organisms strongly influence the diversity of plant species. For example, plant diversity is increased when soil organisms reduce fast growing, dominant plants, or when they stimulate rare plants. However, plant diversity is decreased when the dominant plants selectively benefit from soil biota, or when soil biota selectively reduce rare plants. Following the restoration of ex-agricultural land, root herbivores, soil pathogens, beneficial soil organisms and, on a longer time scale, organisms that break down organic matter stimulate development towards more mature and desirable habitats. Therefore, the composition of the soil community, as well as its changes over time, are crucial for the process of biodiversity restoration and conservation. By improving the diversity of the vegetation, other organisms are often helped, and many of these are beneficial to mankind (e.g. pollinating species, as well as species of high conservation value and attractive species that we like to see in our countryside). Additionally, many invertebrates are important as food for birds. This is particularly important as many species are known to be declining in numbers.
- We found that soil communities may respond to specific plant species. The actual plant species and where they grow influence the composition of the soil community under the plants. Currently, food web models are being developed and diversity patterns described for individual plant species in relation to their habitat. This exciting new approach uses novel identification techniques to link data on soil biodiversity and vegetation.
- The dispersal of soil organisms is far less than the spatial scale at which habitat fragmentation occurs. Habitat fragmentation, therefore, has far stronger effects on soil biodiversity than on above-ground organisms. We are suggesting also that habitat fragmentation may exert indirect effects on soil communities through changing the vegetation, or even through complex effects on animals such as birds, which in turn may feed on soil-dwelling animals. There is now a clear indication that soil biodiversity is acting as the "engine room" for the biodiversity we see and desire above ground. Indeed, the link between soil biodiversity and that above ground is an exciting and fast-growing arena, with much potential for sustainable economic growth.
If we are to meet the target set by the Gotburg Council and reduce biodiversity losses by 2010, we clearly need to be more aware of management measures that conserve the best biodiversity of soil organisms. The impacts of land abandonment, habitat fragmentation, farming and climate change are potentially severe on this, often neglected, component of biodiversity on Planet Earth. However, we should be encouraged that adverse changes can be reversed by awareness and active management. To do this is a challenge and will require commitment and resources to implement. CONSIDER is demonstrating that we are only just beginning to understand the value of the world beneath our feet!
