An integrative approach to discern the seed dispersal role of frugivorous guilds in a Mediterranean semiarid priority habitat

PeerJ. 2019 Oct 11:7:e7609. doi: 10.7717/peerj.7609. eCollection 2019.

Abstract

Seed dispersal is an essential process to maintain the viability of plant populations, and understanding this ecological process allows management strategies to be developed to conserve ecosystems. European Union priority habitat 5220* is defined as "Mediterranean arborescent shrubland with Ziziphus lotus" and it represents a favorable microclimate within the severe climatic conditions typical of the semiarid south-eastern region of the Iberian Peninsula. Therefore, the study of seed dispersal in this priority habitat by different frugivorous guilds, is a challenge for its conservation. In this study, we have characterized a mutualistic network of seed dispersal that is mediated by vertebrates (mammals and birds) in the protected habitat 5220*. The aims of this study were to: (i) identify the seed disperser community; (ii) analyze the relative role of key species in the dispersal process; and (iii) compare the functional ecology of the seed dispersal process between mammals and birds. As such, we collected animal faeces to determine seed dispersers taxonomy, identifying the mammals through the visual aspect of the faeces and the birds by DNA barcoding. In the case of birds, we also collected regurgitated seeds in which the disperser species was also identified through molecular techniques. This allowed us to build-up a mutualistic network and to identify the relative role of these animals in seed dispersal. Our results showed that mammals and birds fulfilled complementary roles in seed dispersal, with birds representing the main dispersers of key plants within the 5220* habitat, and mammals the main dispersers of human-cultivated plants. Herein, we provide a useful approach with relevant information that can be used to propose management policies that focus on restoring the threatened 5220* habitat, promoting the role of birds to disperse key species that structure plant communities of this priority habitat.

Keywords: Complementary seed dispersal; DNA barcoding; Mediterranean; Mutualistic networks; Priority habitat 5220*; Vertebrate frugivorous guilds.

Grants and funding

This work was funded by project “Evaluación de las redes de polinización y dispersión de semillas como factores clave para la conservación del hábitat 5220* de la costa de Cartagena” of Autoridad Portuaria de Cartagena. Diana Carolina Acosta Rojas was supported by a Practical Training Scholarship in the R&D and Innovation activities of the University of Murcia (R.- 86/2017). María Victoria Jiménez Franco was supported by a “Juan de la Cierva-formación” postdoctoral grant of the Spanish Ministry of Economy and Competitiveness (reference JCI-2015-23508) and a postdoctoral grant co-funded by the Regional Valencian Government and the European Social Fund (APOSTD/2018/043). Pilar De la Rúa was supported by Project 19908/GERM/2015 of Regional Excellence (Fundación Seneca). Vicente Martínez López was supported by a predoctoral FPU studentship (FPU13/05115). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.