GLoBE is an international research network that conducts pioneering studies on the functioning of river ecosystems at a global scale, and which has a growing number of collaborators in different countries. Luz Boyero, an Ikerbasque Professor from the Stream Ecology group at the UPV/EHU-University of the Basque Country, is the founder and coordinator of the research network, which now comprises over 50 research teams: 'We formulated a hypothesis, designed an experiment and proposed a protocol to all members of the network. Every team follows exactly the same protocol, so that we can be sure that the data generated are truly global and are obtained using the same methodology'. The network members analyse how different stressors, such as biodiversity loss, affect the functioning of river ecosystems.

The latest studies carried out by the network span 40 rivers and headwater streams located in little disturbed regions in 23 countries all over the world. The results, which have been published in the prestigious scientific journals Science Advances and Nature Communications, demonstrate, for the first time at a global scale, the relationship between biodiversity loss (both detritivore and plant) and ecosystem functioning (decomposition of leaf fall and plant litter) in different climate zones. 'The plant litter decomposition process is a good indicator of the health of the ecosystem; it tells us whether the ecosystem is functioning as it should or if something has changed', explains the researcher from the Plant Biology and Ecology Department of the UPV/EHU-University of the Basque Country.

All alterations to ecosystems have their consequences

As the ecologist, who is an expert in biodiversity and the functioning of river ecosystems, explains, one of the principal conclusions drawn by these studies is that 'diversity is very important and biodiversity loss may have serious consequences for the functioning of pristine river ecosystems'. 'Any alteration to any ecosystem will eventually have consequences: species are lost and this alters the processes that take place in them', she adds.

The two studies also demonstrate that 'the severity of these consequences may differ in different regions of the world, depending on the climate zone in question. It seems that the greatest impacts are occurring in the tropics, where regulations are less strict in terms of ecosystem alteration, land use, pesticides and the disturbance of riverside areas. In these regions, the likelihood of certain species being lost is greater than in Europe, for example, where regulations are much stricter in this area', she points out. The international team has observed that 'in the tropics, the impact of species loss is greater, and we also know that more species are being lost due to more severe habitat disturbance'.

Boyero also talks about the difficulties involved in conducting this type of global study: 'the logistics are tricky because there are so many collaborators, since one team cannot travel the world conducting all the experiments'. The researcher has high praise for the work carried out by the network: 'It is very important that many different researchers who are all interested in the same issues remain in contact and agree to work together to demonstrate things at a planetary scale, because the worst impacts are currently occurring at that scale, and it is important to try and find global responses to global problems'. Nevertheless, Boyero also remarks that 'it is difficult to find the money required to conduct this type of project, because there are no global entities that provide this kind of funding, although it is also true that there is increasing awareness of the importance of this kind of work'. The researcher goes on to point out that the network is currently trying to find collaborators in those parts of Africa and Asia where less work has been carried out to date.

Boyero's team is also drafting a protocol for a new global study on microplastic pollution. 'It is as yet unclear whether or not microplastics are present in the ecosystems in which we work, which are mainly rivers and streams in well-conserved areas. We have conducted several experiments locally, as well as in the lab, and now we want to determine whether or not the microplastics that may be present in the atmosphere have reached these ecosystems, and if so, what effects they may be having', concludes Boyero.