The fern genus Tectaria has generally been placed in the family Tectariaceae or in subfamily Tectarioideae (placed in Dennstaedtiaceae, Dryopteridaceae or Polypodiaceae), both of which have been variously circumscribed in the past. Here we study for the first time the phylogenetic relationships of the associated genera Hypoderris (endemic to the Caribbean), Cionidium (endemic to New Caledonia) and Pseudotectaria (endemic to Madagascar and Comoros) using DNA sequence data. Based on a broad sampling of 72 species of eupolypods I (= Polypodiaceae sensu lato) and three plastid DNA regions (atpA, rbcL and the trnL-F intergenic spacer) we were able to place the three previously unsampled genera. Our results show that Cionidium, like Ctenitopsis, Fadyenia, Hemigramma and Quercifilix, is embedded in Tectaria, and the monophyly of Tectaria is therefore corroborated only if these segregate genera are included. Hypoderris is sister to Tectaria brauniana and together they are sister to Triplophyllum, which was found to be monophyletic. Despite their morphological similarity with Tectaria, the genera Pleocnemia and Pseudotectaria were placed in Dryopteridoideae. Polypodiaceae subfamily Tectarioideae (former family Tectariaceae) is hereby defined to include Arthropteris, Hypoderris, Pteridrys, Tectaria and Triplophyllum. Aenigmopteris may also belong here, but this genus remains unsampled.

Replacing recently extinct endemic giant tortoises with extant, functional analogues provide the perhaps best examples of island rewilding to date. Yet, an efficient future application of this conservation action is challenging in an era of climate change. We here present and discuss a conceptual framework that can serve as a roadmap for the study and application of tortoise rewilding in an uncertain future. We focus on three main ecological functions mediated by giant tortoises, namely herbivory, seed dispersal and nutrient cycling, and discuss how climate change is likely to impact these. We then propose and discuss mitigation strategies such as artificial constructed shade sites and water holes that can help drive and maintain the ecosystem functions provided by the tortoises on a landscape scale. The application of the framework and the mitigation strategies are illustrated with examples from both wild and rewilded populations of the Aldabra giant tortoise, Aldabrachelys gigantea , in the Western Indian Ocean. This article is part of the theme issue ‘Trophic rewilding: consequences for ecosystems under global change’.

In recent years, it has become clear that frugivory and seed dispersal (FSD) by turtles and tortoises is much more common than previously thought. We here review published and unpublished records of chelonian FSD, and assess the role of chelonians as seed dispersers, from individual species to the community level. We first discuss the distribution of chelonian FSD and the characteristics of the fruit and/or seed species eaten and dispersed by chelonians. We then use the seed dispersal efficiency framework to explore the quantitative and qualitative components of seed dispersal by tortoises and turtles, embarking on a journey from when the fruits and/or seeds are consumed, to when and where they are deposited, and assess how efficient chelonians are as seed dispersers. We finally discuss chelonian FSD in the context of communities and of chelonians as megafauna. A substantial proportion of the world's aquatic and terrestrial turtles and a major part of testudinid tortoises (71 species in 12 families) include fruits and/or seeds in their diet; fruits of at least 588 plant species in 121 families are ingested and/or dispersed by chelonians. For some chelonians, overall or in certain seasons, fruit may even form the largest part of their diet. Contrary to seed dispersal by lizards, the other major reptilian frugivores, chelonian FSD is not an island phenomenon in terms of geographic distribution. Nevertheless, on islands tortoises are often among the largest native terrestrial vertebrates – or were until humans arrived. We synthesise our knowledge of chelonian FSD, and discuss the relevance of our findings for conservation and restoration, especially in relation to rewilding with large and giant tortoises.

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