Differences between space and time in biodiversity
The largest difference between spatial and temporal beta diversity was
the property of the species pool. In the spatial context, if an observer
moves sufficiently far from one location to a different region, the
composition of the species pool will differ, and eventually, there will
be no common species between the first and the second place; thus, the
value of spatial beta diversity reaches 1. In contrast, in a temporal
context, if it is not assumed that the composition of the species pool
changes over time, it is rare to have a situation where common species
are completely absent from the species composition at the outset.
Surely, in evolutionary time scale, the species pool would gradually
change, but at the ecological time scale (e.g. less than a hundred
years), dramatic changes in the species pool should not be hypothesised
as a normal condition. However, the influence of recent climate change
and other anthropogenic disturbances will change the composition of the
species pool through species distributional shifts (Dornelas et al.,
2014; Koide, Yoshikawa, Ishihama, & Kadoya, 2022). Therefore, these
influences would increase the upper limits of temporal beta diversity.
The present study focused only on neutral dynamics to understand the
fundamental properties of temporal beta diversity. However, in the
future, more complex models should be studied to understand the
influence of climate change and other anthropogenic disturbances.