Climate change
Climate change is often referred to as one of the biggest threats to
biodiversity . In this meta-analysis, despite the general decline in
soil fauna biodiversity, climate change was not the greatest threat.
However, a more nuanced view may be needed. Based on aboveground
organisms, it might be expected that temperature changes would result in
a decline in biodiversity . However, our results further reinforce the
hypothesis that soils can buffer the impacts of temperature change (also
found in ). Indeed, the observed decline was due to clear negative
effects of reduced water availability, which has previously been shown
in other meta-analyses to be a strong driver of soil biodiversity . This
is cause for concern, as areas of climate change-induced drought are
increasing . Thus, it is likely that the detrimental impact of drought,
as well as depleted soil fauna community will result in reduced
ecosystem function and services in those areas , thus human populations
in those areas may experience two-fold impacts.
Although we categorised drought as a pulse stressor and expected less
impact on soil biodiversity than changes in temperature and gas, it was
impossible to determine and quantitatively compare the strength or
duration of the drought manipulations (relative to the normal levels)
across the different studies with the information available. If the
drought manipulations were too severe (too extreme or too long), there
is the potential for the buffering capacity of the soil to be
significantly reduced , resulting in biodiversity loss. In a similar
vein, the temperature manipulations may also not be an appropriate
length to be considered a press stressor. found that longer
climate-change treatments resulted in more significant effects, although
in their study, the effect was positive.
Considering the length of the treatment application using an alternative
modelling structure, may provide further insights. However, often
temperature changes occur simultaneously with water-regime changes, and
previous studies have demonstrated that if soil water is available for
soil organisms, the effects of other stressors, such as temperature
increases, can be buffered against . Thus, it would be prudent to
consider the synergistic effects of many of the stressors simultaneously
(discussed further below), to fully understand the most detrimental
components of climate change for soil biodiversity.