Biology subjects

Berzaghi, F.

Publications and source records attributed to Berzaghi, F..

7 recordsLinked to original sources

bioRxiv2026

Reduced nutritional quality of plants due to climate change

The effect of climate change on the nutritional quality of plants is poorly understood even though it may have major implications for the food chain and ecosystems. Here we use a dataset covering > 1450 plant species to identify the factors driving plants nutritional properties and develop global projections. We reveal that plant type, CO2, and solar radiation are major drivers controlling nutritional properties. Projections for 2050 show a decline in nutritional quality (-8%, on average at the global scale), measured as the protein to fiber ratio, a strong decrease in minerals (-18%), and a small decrease in digestibility (-3%). Plants in arid and tropical areas will experience the largest decline in quality, which will decline minimally in temperate areas and improve in cold, and polar regions. Quality trends will be opposite in grasses. These results have important implications for livestock management and wildlife conservation.

plant biology↗

bioRxiv2024

Should elephants graze or browse? The nutritional and functional consequences of dietary variation in a mixed-feeding megaherbivore

Unlike specialist browsers and grazers, the diets of mixed-feeding megaherbivores like elephants are complex and broad, comprising numerous plant species of variable nutritional quality. Here, we revisit an unresolved debate on whether browse is more nutritious than grasses for elephants, as browse is thought to have greater crude protein content. We first analyzed carbon isotopes in 102 fecal samples of Asian elephants to quantify the contribution of browsing and grazing to their diet in Nagarahole National Park, southern India. We show that elephants are predominantly browsers in the grass-scarce Nagarahole forests, in contrast with predominant grazing reported in the nearby grass-abundant savannas of the Nilgiri Biosphere Reserve. We then compared the forage quality of high-browsing and high-grazing diets by analyzing these samples for two proxies of crude protein content (CP): nitrogen content (N%) and Carbon-to-Nitrogen ratio (C:N). Interestingly, high-browsing diets did not have higher N% or lower C:N (proxies for high CP) than low-browsing (high-grazing) diets. To explore the generality of this finding, we analyzed nutritional differences (i.e., CP and fibre content values) between browse and grass across 141 plant species consumed by Asian elephants. We show that woody browse and non-legume browse, which are major components of elephant browse, do not have appreciably higher CP than grasses. Our findings suggest that browsing and grazing broadly have similar nutritional value for such bulk-feeding mixed feeders. Finally, based on the observed habitat-wide variation in browsing, we provide a new framework for assessing how elephants shape woody vegetation across the forests and savannas of Asia, with important implications for conservation and carbon cycling.

ecology↗

bioRxiv2022

MegaFeed: Global database of megaherbivores' feeding preferences

Terrestrial mammalian herbivores heavier than ~1000 kg, also known as megaherbivores, perform unique ecological functions due to their combination of heavy body mass, extended home ranges, abundant biomass consumption, and highly diverse diet. Megaherbivores can have substantial effects on ecosystem functioning, vegetation structure, and biogeochemical cycles. Elephants (family Elephantidae) and rhinoceros (family Rhinocerotidae) are two of the remaining megaherbivores that survived the late Pleistocene extinctions, but their populations have been globally declining in the last century. Feeding preferences are a key factor determining the influence of megaherbivores on ecosystems and plant communities; however, comprehensive and centralized data on megaherbivores food preferences are lacking. Here we present MegaFeed, an extensive dataset of megaherbivores feeding preferences across their distribution. This first version of MegaFeed here described contains more than 12,000 records of feeding preferences for the extant elephant species: Loxodonta africana (African savanna elephant), Loxodonta cyclotis (African Forest elephant), and Elephas maximus (Asian elephant). MegaFeed will contribute to a better understanding of the ecological functions of megaherbivores, evaluate the consequences of their decline, and guide rewilding and conservation initiatives such as habitat restoration and reduction of human-wildlife conflicts.

ecology↗

bioRxiv2022

PNuts: Global spatio-temporal database of plant nutritional properties

Plant nutritional properties (crude protein, fibers, minerals, and carbohydrates) and chemical defenses (tannins and phenols) are key traits determining food quality and feeding preferences of animals and humans. Plant nutritional properties are also relevant to crop production and livestock. Here we present PNuts, a global database containing > 1000 species and > 13,000 records of nutritional properties of different plant organs complete with location and time of collection (year/month/season). Species include crops and wild plants and are classified in six functional groups: legumes, herbs, grasses, lianas, shrubs and trees. Plant organs include leaf, fruit, seed, stem, twigs, flower, root, and bark. PNuts data can be used as inputs for ecological analyses and model parametrization requiring large amounts of data. PNuts provides an important tool to better understand the importance of nutritional properties in plant eco-physiology and the implications for humans and animals food quality and plant-animal interactions in a context of global changes.

plant biology↗

bioRxiv2021

Megaherbivores modify forest structure and increase carbon stocks through multiple pathways

Megaherbivores have pervasive ecological effects. In African rainforests, elephants can increase aboveground carbon, though the mechanisms are unclear. Here we combine a large unpublished dataset of forest elephant feeding with published browsing preferences totaling > 120,000 records covering 700 plant species, including nutritional data for 102 species. Elephants increase carbon stocks by: 1) promoting high wood density tree species via preferential browsing on leaves from low wood density species, which are more digestible; 2) dispersing seeds of trees that are relatively large and have the highest average wood density among tree guilds based on dispersal mode. Loss of forest elephants could cause a 5-12% decline in carbon stocks due to regeneration failure of elephant-dispersed trees and an increase in abundance of low wood density trees. These results show the major importance of megaherbivores in maintaining diverse, high-carbon tropical forests. Successful elephant conservation will contribute to climate mitigation at a scale of global relevance.

ecology↗

bioRxiv2021

Global distribution of mammal herbivore biomass reveals megafauna extinction patterns

Mammalian herbivores strongly shape Earth system processes. A lack of global dynamic models of mammal populations limits our understanding of their ecological role at large scales and the consequences of their extinctions. We developed a mechanistic global model of terrestrial herbivore populations simulated with 37 functional groups defined by analyzing eco-physiological traits of all extant herbivores (n = 2599). We coupled this model with a global vegetation model to predict herbivores biomass maximum potential (pre-industrial) and at present. Natural ecosystems could have sustained a wild herbivore wet biomass of 330 Mt, comprised of 192 Mt by large (body mass > 5 kg) and 138 Mt by small species. Anthropogenic activity reduced large herbivores biomass by 57%, estimated now at 82 Mt; consequently, small herbivores now dominate global herbivore biomass with 98 Mt (-29%). Losses vary greatly across climatic zones and functional groups, suggesting that size is not the only discriminant feature of biomass decline. Actual evapotranspiration is the most important driver of total, large, and small herbivore biomass and explains 64%, 59%, and 49% of its variation, respectively. Energy and water dependency is high for large herbivores, whose biomass is greater in hot and wet areas, challenging the notion that large herbivore biomass peaks in savannas only. Outside Africa and the Tropics, potential-biomass hotspots occur in areas today dominated by humans; this could undermine the recovery of larger species in certain areas. These herbivore biomass estimates provide a quantitative benchmark for setting conservation and rewilding goals at large spatial scales. The herbivore model and functional classification create new opportunities to integrate mammals into Earth System science and models.

ecology↗

bioRxiv2021

Valuation of carbon services produced by wild animals finances conservation

Filling the global biodiversity financing gap will require significant investments from financial markets, which demand credible valuations of ecosystem services and natural capital. However, current valuation approaches discourage investment in conservation because their results cannot be verified using market-determined prices. Here, we bridge the gap between finance and conservation by valuing only wild animals carbon services for which market prices exist. By projecting the future path of carbon service production using a spatially-explicit demographic model, we place a credible value on the carbon-capture services produced by African forest elephants. If elephants were protected, their services would be worth $35.9 billion (24.3-41.2) and store 377 MtC (318-388) across tropical Africa. Our methodology can also place lower bounds on the social cost of nature degradation. Poaching would result in $10-14 billion of lost carbon services. Our methodology enables the integration of animal services into global financial markets with major implications for conservation, local socio-economies, and conservation.

ecology↗