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Horses play a key role in forest management and in reducing the risk of wildfires in Mediterranean forests, thanks to the adaptability of their eating habits. This is the conclusion reached by an interdisciplinary study led by the Universitat Autònoma de Barcelona (UAB) and the University of Lleida (UdL), recently published in the journal Agroforestry Systems. Source: Timberbiz The research, which included the participation of Boumort Wildland, the Miranda Foundation, the Forest Horses association, and the University of Barcelona (UB), reveals that horses adapt their diet according to breed, environment and use. This flexibility helps them play a complementary role alongside other herbivores in sustainable fire prevention strategies, given that their grazing reduces fuel loads and maintains open landscapes. The study was co-authored by researchers from the Department of Animal and Food Science at the UAB Jordi Bartolomé and Araceli Gort-Esteve. “Until now research on extensive herding and forest fire prevention has focused mainly on sheep and goats, with some isolated studies done on breeds of rustic cattle. There have been very few studies on horses within this context, since traditionally they are classified as plant grazers that have little effect on woody vegetations,” said Ariadna Nieto-Espinet, Ramón y Cajal researcher at the UdL and zooarchaeologist. “Our work is one of the first to use empirical data to analyse their potential in forest management in the Mediterranean.” The study analysed three specific cases with the aim of exploring the potential of horses in clearing forest undergrowth. At the Boumort National Game Reserve, the Przewalski’s horses live in semi-freedom in a mosaic landscape with a low herd count of 0.02 animals per hectare (ha) and year. At the Garraf Natural Park, the rustic Pottoka horses continuously grazed and also roamed in semi-freedom for one year, with a low herd demography (0.2 animals/ha/year). The third case examined crossbred horses grazing for short periods of time, with supplementary food and a high animal count (2.5 animals/ha for the duration of one and a half months). The team analysed the horses’ diet based on 50 fresh faecal samples. “We used microhistological analysis of plant epidermis in faeces and advanced statistical models to obtain a precise assessment of the shifts in diet of these animals,” said Araceli Gort-Esteve, researcher at the UAB and the Institute for Game and Wildlife Research (IREC-CSIC). Among the species found were woody plants of the Quercus, Juniperus and Pistacia genera, and other herbaceous species such as the Mediterranean false brome (Brachypodium retusum). The results indicate that Przewalski’s wild horses, in a mosaic landscape with patches of forest, scrub, and meadows, keep the fields cleared throughout the year by eating mainly grasses, with little impact on woody vegetation. Rustic breeds, such as the Pottoka, adapt to long periods of grazing by initially consuming fine, highly flammable grasses, and then moving on to woody plants as the grasses are depleted. They effectively manage both fine and coarse fuels, contributing to the control of the undergrowth. Finally, crossbred horses, subjected to intensive short-term grazing with supplementary feeding, quickly move from fine fuels to woody plants, demonstrating their potential for targeted management actions. “The results with Pottoka and crossbred horses clearly show that horses, considered grazers with a preference for grasses, can quickly adapt to available resources, including woody species. This flexibility makes them a valuable resource for fire prevention strategies in Mediterranean landscapes, complementary to sheep and goats,” said UAB lecturer Jordi Bartolomé Filella. “Rustic breeds, often less valued today, have a great adaptive capacity that makes them key in silvopastoral tasks. Our study shows that horses can not only contribute to undergrowth control, but also to the maintenance of open spaces and mosaic landscapes,” said Ariadna Nieto-Espinet. The research team agrees that more long-term studies are needed to quantify the direct impact of horses on reducing flammable biomass. Nevertheless, they believe that their dietary adaptability could make them a promising tool in more sustainable forest management strategies, especially in a context of climate change, rural depopulation, and increased risk of fires. Original article: Gort-Esteve, A., Filella, J.B., Molinero, X.R. et al. Dietary strategies of feral and domestic horses under varying grazing pressures: insights for Mediterranean forest management. Agroforest Syst 99, 208 (2025). https://doi.org/10.1007/s10457-025-01291-9  

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Sweden and Finland could suffer “dire” economic consequences if they are forced to harvest less forest for wood products in order to meet their EU-mandated climate targets, according to the two countries. Source: Reuters As part of the European Union’s plans to reach net zero emissions by 2050, Sweden and Finland have been tasked with increasing the amount of CO2 bound up by forests. Industry and environmental groups both see forests a key part in fighting climate change. Forestry firms stress the economic benefits, sustainable management and the role of biofuels and wood in replacing fossil fuels, plastic and concrete. But scientists have warned that over-logging, monoculture and other industry practices are reducing the ability of forests to absorb carbon dioxide and put Europe’s climate goals at risk. In a joint letter to European Commission President Ursula von der Leyen, Sweden and Finland said their targets – an increase in CO2 uptake of around four million tonnes annually by 2030 for Sweden and three million tonnes for Finland were unrealistic. Reduced logging would “entail dire consequences for our economies as well as labour markets” the two countries said in the letter. Forests cover around 70% of Finland and Sweden. Wood products make up more than 10% of Sweden’s exports and almost a fifth for Finland. More than 200,000 people work in the sector. EU governments are currently negotiating the 2040 climate target and the role of forests a key question. Sweden and Finland said they supported an EU-wide net emission reduction target of 90% for 2040 covering both emissions and removals, but that targets must be realistic. “A successful future for Europe relies on a successful clean transition, combining growth, jobs and decreased emissions,” they said.

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One of the great challenges of ecology is to understand the factors that maintain, or undermine, diversity in ecosystems, researchers write in a new report in the journal Science. The researchers detail their development of a new model that — using a tree census and genomic data collected from multiple species in a forest — can predict future fluctuations in the relative abundance of those species. Source: Timberbiz University of Illinois Urbana-Champaign plant biology professor James O’Dwyer led the new research with Andy Jones, a professor of botany and plant pathology at Oregon State University, and James Lutz, a professor of forest ecology at Utah State University. O’Dwyer has spent most of his career studying the factors that drive ecological change and using that knowledge to build models that reliably predict how individual species and forest communities will change over time. “This work is crucial because changes in abundance or loss of a species from a forest can have cascading effects on other species,” O’Dwyer said. Forests with lower tree diversity are more susceptible to attack by pathogens or pests. Being able to predict which species are at risk could help understand how forests will change in the future. “Species diversity is lower in forests of the western United States than in other parts of the US, but most species have unique roles in the forest,” said Lutz, who, since 2010 has conducted an annual census of the Wind River Forest Dynamics plot in southern Washington state, the focus of the new study. “Losing one species, when there are few to begin with, could result in a less productive forest and potentially one that doesn’t support as many small plants or animals.” But predicting future changes in species abundance is a formidable task, the researchers said. “In a forest, there are constantly varying environmental conditions, as well as different tree neighbourhoods, with species competing for resources like sunlight and water,” Lutz said. “Neighbouring trees influence each other while living and after death, as snags and wood, all amidst variation in rain and soil conditions.” Simply collecting the data needed to determine which elements are most influential requires years of painstaking work. Luckily for the researchers, many long-term studies of forests are well underway, led by teams of scientists all over the world. Some of these efforts are organized under the Smithsonian Forest Global Earth Observatory, which has amassed data from 78 sites across the world spanning several decades. The Wind River Forest Dynamics Plot is one of those sites. The new study uses data from that plot to build on previous modelling efforts. In a 2023 study published in the journal Nature, O’Dwyer and graduate student Kenneth Jops developed a model for predicting whether two or more species will continue to coexist in a shared environment. That approach focused on the life history traits of each species, which primarily consist of timelines of how fast each organism grows, reproduces and dies. From a matrix built from this data, along with a census of trees in the forest, the model calculated each species’ “effective population size.” Two species with the same or similar effective population sizes were more likely to continue to coexist, the researchers found. “The upshot of that study is that we identified certain combinations of life histories across plant communities that act to maintain diversity over longer timescales, while other combinations would lead to lower diversity,” O’Dwyer said. In a more recent study of a tropical forest in Panama, another ForestGEO site, O’Dwyer and his colleagues extended the approach to multispecies systems, finding that the effective population size was helpful in predicting short-term population fluctuations. “We were able to infer those life history differences because we had access to data from one of the most well-studied forest plots in the world,” O’Dwyer said. “With anything less than the decades of data from that plot, our estimates would have been much less reliable.” But collecting decades of data from a single forest is not feasible for most studies, and the team sought to find a more streamlined approach. Instead of collecting life history data for dozens of species over decades, Jones led an effort to collect genomic data from about 100 individuals of each of eight species of trees that make up roughly 90% of the stems and almost all the biomass in the Wind River plot. These were not complete genomes, but a sampling of genes that, the researchers hoped, would reflect key events in the life history of each tree species. “Effective population size is a fundamental concept in evolutionary biology, first described almost 100 years ago. Although the true nature of the factors that ultimately determine effective population size is complex, it is perhaps easiest to think of it as the number of individuals that contribute offspring, and therefore their genes, to the next generation,” Jones said. “The effective population size is typically lower — sometimes much lower — than the number of trees of a species that we can count in a forest. This is because some individual trees leave more offspring than others, which is how populations evolve. When this occurs, we find an increase in non-random associations between genes.” “That balance between random and non-random associations in the genome is closely related to effective population size,” O’Dwyer said. “Those life history traits are in the background, shaping that genomic data. I would say the genome is like a hidden recording device of the history of that species in that forest.” The researchers incorporated the genomic data into their model, which also included data from a census of all the trees over one centimetre in diameter in the Wind River plot in 2011. The model accurately predicted fluctuations in the abundance of the eight species in 2016 and 2021, outperforming other models. “The predictions were highly correlated with the observed fluctuations in abundance,” O’Dwyer said. “That’s very exciting.” “My sense is that the population genomic variation that we’re looking at is an underused resource,” […]

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