4.6 Indicators
When applying the three indicators proposed for the Swedish Agency of
Marine and Water Management (SwAM; Johannesson & Laikre, 2020) we find
that the proposed limiting threshold values are exceeded in some of the
29 monitored populations (Figure 7a). However, when considering the
metapopulations that these populations belong to, positive trends in
other populations of the same metapopulations compensate for the
negative trends in several cases. Only two of ten full systems (Figure
7b) show warning signals for the ΔH indicator. MetapopulationN e is however, often below the 500-threshold
resulting in warning signals from the N eindicator. We underline that the true meta-N e can
be larger in these systems because we have likely not sampled the full
metapopulations in any of the present cases. Sampling over substantially
larger areas are needed to resolve this issue. On the other hand, the
generally low N e estimates observed underlines
the vulnerability of these systems – if they become fragmented and
isolated, local N e is low and reduced
connectivity will rapidly result in elevated rates of diversity loss.
Protecting large, interconnected systems are thus important for the
conservation and viability of fish in small mountain lake systems. We
also apply the indicators for CBD (Figure 7c), and in the present case
the results are largely consistent with the results from the national
(SwAM) indicators.