bioRxiv Science⌕ Search

Biology subjects

Soliveres, S.

Publications and source records attributed to Soliveres, S..

8 recordsLinked to original sources

Lonely plants in arid land are functionally hyperdiverse

In Gross et al.1 we produced the largest ever standardized dryland plant trait database including 133,769 trait measurements from 301 perennial plant species surveyed across 326 plots and six continents. Our findings indicate that arid and hyper-arid drylands act as a global reservoir of plant phenotypic diversity, challenging the common assumption that harsh environmental conditions reduce plant trait diversity. Tordoni et al.2 speculate that the larger phenotypic diversity in harsh environments found in our study is overestimated and misinterpreted. The re-analyses presented here further confirm that the patterns we originally reported are robust, and thus that the concerns from Tordoni et al. are not well-founded and do not apply to our study. We stand for the main conclusions of our study and maintain that lonely plants in arid land are functionally hyperdiverse.

ecology↗

Urban crops demonstrate comparable potential for organic carbon storage as natural ecosystems.

Urban greenspaces, encompassing parks, golf courses, roundabouts, and urban crops, have potential to offset urban carbon footprints by storing soil organic carbon (SOC). This study analyzed particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) stocks in topsoil across 27 Iberian cities, comparing urban greenspaces with natural ecosystems under varying climatic and edaphic conditions. Results revealed that urban greenspaces store comparable SOC stocks to natural ecosystems, with MAOC stocks being more dominant and stable across land-use types. POC stocks showed variability, particularly lower in roundabouts and parks compared to natural ecosystems, but remained similar in golf courses and urban crops. SOC fractions correlated inversely with mean annual temperature (MAT), emphasizing the need for cooling strategies in urban areas to preserve stable carbon pools. While MAOC exhibited saturation at higher SOC levels, POC showed a linear increase. This study highlights the importance of tailored management practices to enhance carbon storage in urban soils for climate change mitigation.

biochemistry↗

Loss of species richness with land use intensity is explained by a reduction in niche differences.

Increases in land use intensity (LUI) reduce species richness. However, we have a poor understanding of how underlying coexistence mechanisms are altered by land use and whether diversity loss occurs due to changes in plant-plant interactions (competition and facilitation) or in species intrinsic growth rates. We expect that LUI could reduce stabilizing niche differences and the indirect interactions that promote coexistence (e.g., intransitivity), while increasing competitive inequalities between species. To test the importance of these different processes, we use 8-yr time series from 150 grasslands differing in LUI to evaluate the role of direct and indirect interactions in promoting coexistence between 50 plant species. We show that LUI reduces the number of coexisting species mostly by causing a non-linear reduction in niche differences, rather than by enhancing competitive inequalities. However, surprisingly, niche differences remained important in stabilizing coexistence between those species remaining at high LUI. Indirect interactions were generally less important than direct ones, and played a moderate role in promoting coexistence in smaller assemblages of species at intermediate LUI. Our models could accurately reproduce the decline in diversity seen with LUI, indicating that our time series approach captures the important interactions between species. By analyzing land use effects through recent advances in structural stability applied to community ecology we provide a more mechanistic understanding of its effects. Our results highlight the importance of identifying the niche differences that are lost with increasing LUI, to better predict and manage effects of land use on biodiversity. Significant statementHuman land use is a major threat to grassland biodiversity. Grasslands with high rates of fertilization, grazing and mowing, contain many fewer plant species. Knowing the underlying causes is necessary for a better management of biodiversity. Here we apply ecological theory to spatiotemporal data on changes in plant abundance in managed grasslands in central Europe. We show that the observed decline in diversity can be explained by how interactions among plant species change with increases in land use intensity. In particular, intensive land use removes the stabilizing effect of self-limiting processes that buffer species against extinction as well as limit competitive dominance. Therefore, actions to promote these stabilizing dynamics among interacting species seem key to restore plant diversity.

ecology↗

Plant attributes interact with fungal pathogens and nitrogen addition to drive soil enzymatic activities and their temporal variation

O_LINitrogen enrichment can alter soil communities and their functioning directly, via changes in nutrient availability and stoichiometry, or indirectly, by changing plant communities or higher trophic levels. In addition, soil biota and their associated functions may show strong temporal changes in their response to environmental changes, yet most current studies have only focused on one of these potential drivers or have measured soil functioning only once during the peak growing season. Therefore, we know little about the relative importance of the different mechanisms by which nitrogen enrichment affects soil communities, functioning and temporal stability. C_LIO_LIIn a large grassland experiment manipulating nitrogen enrichment, plant species richness, functional composition and foliar pathogen presence, we measured activities of two enzymes, {beta}-glucosidase and acid phosphatase, as indicators of soil functioning. We did so across different seasons and years to assess their temporal dynamics and how consistently they responded to multiple drivers. C_LIO_LINitrogen addition was the most important driver of {beta}-glucosidase activity, and it increased {beta}-glucosidase activity over time. However, interactions between plant attributes and fungicide application were the main drivers of acid phosphatase activity. The temporal stability of soil enzyme activity was differently affected by two facets of plant diversity (species richness [+] and functional diversity [-]), with nitrogen and fungicide addition dampening these effects. C_LIO_LISynthesis: Fungicide effects, and their interactions with plant diversity, show the importance of foliar pathogens not only for above-but also for belowground processes, and highlight the possibility that these plant enemies are major modulators in the relationships between plant diversity and ecosystem functioning. We also show the need to consider temporal dynamics in belowground processes to better understand the responses of ecosystem functioning to environmental changes such as nutrient enrichment. C_LI

ecology↗

Context-dependency in biodiversity-multifunctionality relationships is driven by nitrogen availability and plant functional composition

The ability of an ecosystem to deliver multiple functions at high levels (multifunctionality) typically increases with biodiversity but there is substantial variation in the strength and direction of biodiversity effects, suggesting context-dependency. A better understanding of the drivers of this context dependency is essential to predict effects of global change on ecosystems. To determine how different factors modulate the effect of diversity on multifunctionality, we established a large grassland experiment with 216 communities, crossing a manipulation of plant species richness (1, 4, 8, 20 species) with manipulations of resources (nitrogen enrichment), plant functional composition (gradient in mean specific leaf area [SLA] to manipulate abundances of exploitative, fast-growing vs. conservative, slow-growing species), plant functional diversity (variance in SLA) and enemy abundance (foliar fungal pathogen removal). We measured ten above- and belowground functions, related to productivity, nutrient cycling and energy transfer between trophic levels, and calculated ecosystem multifunctionality. Plant species richness and functional diversity both increased multifunctionality, but their effects were context dependent. Species richness increased multifunctionality only when communities were assembled with fast growing (high SLA) species. This was because slow species were more redundant in their functional effects, whereas different fast species tended to promote different functions. Functional diversity also increased multifunctionality but this effect was dampened by nitrogen enrichment. However, unfertilised, functionally diverse communities still delivered more functions than low diversity, fertilised communities. Our study suggests that a shift towards fast-growing exploitative communities will not only alter ecosystem functioning but also the strength of biodiversity-functioning relationships, which highlights the potentially complex effects of global change on multifunctionality.

ecology↗

Decomposition disentangled: a test of the multiple mechanisms by which nitrogen enrichment alters litter decomposition

O_LINitrogen (N) enrichment has direct effects on ecosystem functioning by altering soil abiotic conditions and indirect effects by reducing plant diversity and shifting plant functional composition from dominance by slow to fast growing species. Litter decomposition is a key ecosystem function and is affected by N enrichment either by a change in litter quality (the recalcitrance of the plant material) or through a change in soil quality (the abiotic and biotic components of the soil that affect decomposition). The relative importance of soil and litter quality and how the direct and effects of N alter them remains poorly known.\nC_LIO_LIWe designed a large grassland field experiment manipulating N enrichment, plant species richness and functional composition in a full factorial design. We used three complementary litter bag experiments and a novel structural equation modelling approach to quantify the relative effects of the treatments on litter and soil quality and their importance for total decomposition.\nC_LIO_LIOur results indicate that total decomposition was mostly driven by changes in litter quality rather than soil quality. Litter quality was affected by the nutrient contents (N and calcium) and structural components of the litter (leaf dry matter content, fibres). N enrichment increased litter decomposition mostly indirectly through a shift in functional composition toward faster growing plant species producing higher quality litter. N enrichment also had effects on soil, by directly and indirectly affected vegetation cover, but this had relatively few consequences for the total decomposition rate.\nC_LIO_LISynthesis. Our approach provides a mechanistic tool to test the drivers of litter decomposition across different ecosystems. Our results show that functional composition is more important than richness or soil quality in determining litter decomposition and that N enrichment effects mainly occur via above- rather than belowground processes. This highlights the importance of considering shifts in plant species composition when assessing the effects of N enrichment on decomposition.\nC_LI

ecology↗

The interplay between facilitation and habitat type drive spatial vegetation patterns in global drylands

The size distribution of discrete plant patches (PSD), a common descriptor of the spatial patterns of vascular vegetation, has been linked to variations in land degradation and ecosystem functioning in drylands. However, most studies on PSDs conducted to date have focused on a single or a few study sites within a particular region. Therefore, little is know on the general typology and distribution of PSDs at the global scale, and on the relative importance of biotic and abiotic factors as drivers of their variation across geographical regions and habitat types. We analyzed 115 dryland plant communities from all continents except Antarctica to investigate the general typology of PSDs, and to assess the relative importance of biotic (plant cover, frequency of facilitation, soil amelioration, height of the dominant species) and abiotic (aridity and sand content) factors as drivers of PSDs across contrasting habitat types (shrublands and grasslands). We found that both power-law and lognormal PSDs were generally distributed regardless of the region of the world considered. The percentage of facilitated species in the community drives the emergence of power-law like spatial patterns in both shrublands and grasslands, although mediated by different mechanisms (soil and climatic amelioration, respectively). Other drivers of PSDs were habitat-specific: height of the dominant species and total cover were particularly strong drivers in shrublands and grasslands, respectively. The importance of biotic attributes as drivers of PSDs declined under the most arid conditions in both habitats. We observed that PSDs deviated from power law functions not only due to the loss of large, but also of small patches. Our results expand our knowledge about patch formation in drylands and the habitat-dependency of their drivers. They also highlight different ways in which facilitation may act on ecosystem functioning through the formation of plant spatial patterns.

ecology↗

Species-specific adaptations determine how aridity and biotic interactions drive the assembly of dryland plant communities

O_LIDespite being a core ecological question, disentangling individual and interacting effects of plant-plant interactions, abiotic factors and species-specific adaptations as drivers of community assembly is challenging. Studies addressing this issue are growing rapidly, but they generally lack empirical data regarding species interactions and local abundances, or cover a narrow range of environmental conditions.\nC_LIO_LIWe analysed species distribution models and local spatial patterns to isolate the relative importance of key abiotic (aridity) and biotic (facilitation and competition) drivers of plant community assembly in drylands worldwide. We examined the relative importance of these drivers along aridity gradients and used information derived from the niches of species to understand the role that species-specific adaptations to aridity play in modulating the importance of community assembly drivers.\nC_LIO_LIFacilitation, together with aridity, was the major driver of plant community assembly in global drylands. Due to community specialization, the importance of facilitation as an assembly driver decreased with aridity, and became non significant at the border between arid and semiarid climates. Under the most arid conditions, competition affected species abundances in communities dominated by specialist species. Due to community specialization, the importance of aridity in shaping dryland plant communities peaked at moderate aridity levels.\nC_LIO_LISynthesis: We showed that competition is an important driver of community assembly even under harsh environments, and that the effect of facilitation collapses as driver of species relative abundances under high aridity because of the specialization of the species pool to extremely dry conditions. Our findings pave the way to develop more robust species distribution models aiming to predict the consequences of ongoing climate change on community assembly in drylands, the largest biome on Earth.\nC_LI

ecology↗