Data from: Restored streams recover food web properties but with different scaling relationships when compared to natural streams

Despite extensive studies revealing differences in the composition of
aquatic assemblages between restored streams and natural or
pre-restoration states, understanding the ecological consequences and
trajectories of stream restoration remains challenging. Food webs are an
important way of mapping biodiversity to ecosystem functioning by
describing feeding linkages and energy transfer pathways. Describing food
webs can provide ecological insights into stream restoration. This study
analyzed an unprecedentedly large quantity of food web data (>
1,700 webs) based on long-term (2008–2018) biomonitoring data in South
Korea using a feeding link extrapolation. By doing so, we aimed to
describe general patterns for the reassembly of aquatic food webs in
restored streams. Specifically, we analyzed 12 indices related to the food
web structure and robustness of restored streams and compared them with
those of natural streams. First, the species richness, link numbers, link
density, and connectance of the restored streams were all lower than those
of the natural streams, indicating smaller food webs with less complexity.
Second, the scaling relationship analyses between the other food-web
indices and species richness and connectance showed different mechanisms
for structuring food webs in restored streams compared to natural streams.
In particular, greater generalist feeding by consumers was identified as a
major mechanism that increased the connectance of restored streams, which
may increase their robustness against external disturbances. The fractions
of the top, intermediate, and basal nodes in the restored streams changed
rapidly as species richness increased compared with those of natural
streams. Food web connectance and robustness in the restored streams
tended to increase over time, reaching a level similar to that of natural
streams. This suggests that the long-term ecological recovery of the
restored food webs is underway. Overall, our findings indicate that
restored stream food webs have ecological features distinct from those of
natural streams, suggesting high compositional flexibility, and that
consumers with a broad diet are the major driving forces for these
differences. Our food web analyses provide a greater understanding of
restored streams and help support sustainable stream management through
restoration strategies. These results provide new insights into the
ecological potential of stream restoration.