Researchers at the Doñana Biological Station have analyzed which species have an essential role in the seed dispersal of Phoenicean juniper in the Doñana National Park.

Juniperus phoenicea subsp. Turbinata is a subspecies of J. phoenicea, a large shrub inhabiting in southern Spain. It is an endozoochorous species, that is, it disperses its seeds thanks to vertebrate animals consuming its fruits. Since the protection of Doñana, this species has spread rapidly through this natural area in a few decades and the role of animal in this process is still unknown.

This has motivated the study about how different bird and mammal species are interacting with J. phoenicea along throughout natural expansion gradient. This fact will allow to better understand the role of these interactions in this ecological context.

It is crucial to understand that plant-animal interactions determine biodiversity persistence. In fact, between 70-90% of known woody species depend on vertebrate animals for seed dispersal, highlighting their critical role in colonization processes and plant range shifts.

Working with Juniperus phoenicea

This study on the seed dispersal of J. phoenicea is based on data on plant-interaction animals, as well as the analysis of complex networks. Researchers combined network analyses with field surveys, sampling interactions between individual plants and frugivores by DNA-barcoding and phototrapping over two seasons. Phototrapping allow the team to observe animals feeding on the fruits of this plant, avoiding human presence. AND-Barcoding, on the other hand, allowed to identify which species were involved in dispersal after the analysis of the DNA present in scats or regurgitated seeds.

As a result of the combination of both techniques, researchers created an interaction network and evaluated whether the interactions were being reconfigured throughout the expansion gradient.

Forest regeneration

According to researcher Jorge Isla: "In a world that is changing faster and faster, natural regeneration of new available areas has become very common. This regeneration consists first of the arrival in new areas of pioneer plant species that initiate successional processes that eventually end with the establishment of new mature forests". In a few decades, a large part of Europe's forests will be secondary forests, which are currently forming and regenerating.

Since a large number of these plant species need their interactions with animals in order to reproduce (pollination by insects) and/or disperse (dispersal by birds and mammals), it is essential to understand which species play a determining role in these expansion processes.

Science and decision making

Decision makers on biodiversity management and conservation need scientific evidences to support such actions and, in this particular case, on the potential of ecosystems for their own regeneration. One of the key conclusions of this study is that intervention is needed to maintain functionality of natural ecosystems.

Therefore, focusing on the management perspective, the results obtained in this study support the idea that it is preferable to work on management plans aimed at conserving these interactants (frugivorous animals) than to develop massive manual reforestation protocols.

"Natural systems are prepared to regenerate themselves while it would imply much effort and many resources for us to do it", says Jorge Isla. "In fact, this is the first time that a reconfiguration of this type of interactions during natural expansion processes has been shown". This reconfiguration results in a greater dispersal potential from the colonization fronts, facilitating and accelerating the natural regeneration of ecosystems.

The LifeWatch ERIC project - SUMHAL

SUMHAL – Sustainibility for Mediterranean Hotspots in Andalusia integrating LifeWatch ERIC is a European project framed within the LifeWatch ERIC pan-European distributed e-Science infrastructure. It is funded by the Spanish Ministry of Science and Innovation, through the FEDER funds [SUMHAL, LIFEWATCH-2019-09-CSIC-4, POPE 2014-2020].

Its main objective is to contribute to the conservation of biodiversity in natural or semi-natural systems in the western Mediterranean, based on high-tech infrastructures, and the association between highly specialised research personnel and the public.

It also seeks to establish a technologically efficient and scientifically robust system that combines field work, virtual research environments (VREs) for the recording, storage, analysis and dissemination of the conservation status and threats of Andalusian biodiversity and the most frequent ecosystems, offering virtual tools, not only to researchers, but also to society and conservation agencies, for the assessment of the current situation after considering the past, making informed decisions and taking adaptive management actions, in order to reduce future vulnerability and the loss of natural heritage.

Reference

Jorge Isla, Miguel Jácome-Flores, Juan M. Arroyo, Pedro Jordano

The turnover of plant–frugivore interactions along plant range expansion: consequences for natural colonization processes

Proceedings of the Royal Society B, 290, 20222547 (2023)

DOI: http://doi.org/10.1098/rspb.2022.2547

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