Cross Taxon Congruence Between Lichens and Vascular Plants in a Riparian Ecosystem

Bacaro Bacaro,Muggia Muggia,Petruzzellis Petruzzellis,Gonnelli Gonnelli,Benesperi Benesperi,Tordoni Tordoni,Guidi Guidi,Marignani Marignani,Lastrucci Lastrucci,Martellos Martellos,Maccherini Maccherini,Napolitano Napolitano,Re Re

doi:10.3390/d11080133

Bacaro Bacaro, Muggia Muggia + Show 11 more

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https://doi.org/10.3390/d11080133

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Abstract

Despite that congruence across taxa has been proved as an effective tool to provide insights into the processes structuring the spatial distribution of taxonomic groups and is useful for conservation purposes, only a few studies on cross-taxon congruence focused on freshwater ecosystems and on the relations among vascular plants and lichens. We hypothesized here that, since vascular plants could be good surrogates of lichens in these ecosystems, it would be possible to assess the overall biodiversity of riparian habitats using plant data only. In this frame, we explored the relationship between (a) species richness and (b) community composition of plants and lichens in a wetland area located in central Italy to (i) assess whether vascular plants are good surrogates of lichens and (ii) to test the congruence of patterns of species richness and composition among plants and lichens along an ecological gradient. The general performance of plant species richness per se, as a biodiversity surrogate of lichens, had poor results. Nonetheless, the congruence in compositional patterns between lichens and vascular plants varied across habitats and was influenced by the characteristics of the vegetation. In general, we discussed how the strength of the studied relationships could be influenced by characteristics of the data (presence/absence vs. abundance), by the spatial scale, and by the features of the habitats. Overall, our data confirm that the more diverse and structurally complex the vegetation is, the more diverse are the lichen communities it hosts.

Highlights

The growing impact of human-induced changes on natural ecosystems, such as land transformation and habitat degradation, is leading to the pressing need for straightforward methodologies for monitoring biodiversity in space and time [1,2,3,4,5]
Despite that congruence across taxa has been proved as an effective tool to provide insights into the processes structuring the spatial distribution of taxonomic groups and is useful for conservation purposes, only a few studies on cross-taxon congruence focused on freshwater ecosystems and on the relations among vascular plants and lichens
The total amount of species recorded in the 184 plots was 238, of which 193 were vascular plants and 45 were lichens (Table 1)

Summary

Introduction

The growing impact of human-induced changes on natural ecosystems, such as land transformation and habitat degradation, is leading to the pressing need for straightforward methodologies for monitoring biodiversity in space and time [1,2,3,4,5]. Cross-taxon congruence analysis can be expressed as the correlation in patterns of species richness and/or diversity [8] or, in a multi-species context, as community concordance (i.e., the relationship among compositional patterns of multiple taxonomic groups across sites [9,10]). Cross-taxon congruence occurs when diversity and/or composition patterns of different biological groups covary spatially [11]. The interest in biological surrogates during the last decade has resulted in an increasing number of studies testing their effectiveness, in a multiplicity of locations and at different spatial scales [12]. The effectiveness of surrogate taxa as ecological indicators for biodiversity assessment depends on other factors, such as the spatial scale of analysis and the choice of predictor variables [19]. The choice of the study scale is, crucial to avoid spurious or undetected relationships among the collected variables and it could influence the time/cost of the sampling effort as well [20]

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