The impact of land-use changes and management intensification on bacterial communities in the last decade: a review.

In the last decade, advances in soil bacterial ecology have contributed to increasing agricultural production. Brazil is the world leading agriculture producer and leading soil biodiversity reservoir. Meanwhile, there is still a significant gap in the knowledge regarding the soil microscopic life and its interactions with agricultural practices, and the replacement of natural vegetation by agroecosystems is yet to be unfolded. Through high throughput DNA sequencing, scientists are now exploring the complexity of soil bacterial communities and their relationship with soil and environmental characteristics. This study aimed to investigate the progress of bacterial ecology studies in Brazil over the last 10 years, seeking to understand the effect of the conversion of natural vegetation in agricultural systems on the diversity and structure of the soil microbial communities. We conducted a systematic search for scientific publication databases. Our systematic search has matched 62 scientific articles from three different databases. Most of the studies were placed in southeastern and northern Brazil, with no records of studies about microbial ecology in 17 out of 27 Brazilian states. Out of the 26 studies that examined the effects of replacing natural vegetation with agroecosystems, most authors concluded that changes in soil pH and vegetation cover replacement were the primary drivers of shifts in microbial communities. Understanding the ecology of the bacteria inhabiting Brazilian soils in agroecosystems is paramount for developing more efficient soil management strategies and cleaner agricultural technologies.

Ecological transcriptomics reveals stress response pathways of a ground-herb species in a waterlogging gradient of Amazonian riparian forests.

Environmental stress is a fundamental facet of life and a significant driver of natural selection in the wild. Gene expression diversity may facilitate adaptation to environmental changes, without necessary genetic change, but its role in adaptive divergence remains largely understudied in Neotropical systems. In Amazonian riparian forests, species distribution is predominantly influenced by species' waterlogging tolerance. The flooding gradient delineates distinct wetland forest types, shaping habitats and species characteristics. Here we investigated the molecular basis of environmental stress response in a tropical ground-herb species (Ischnosiphon puberulus) to environmental variation in Amazonian riparian forests. We compared environmental variables and gene expression profiles from individuals collected in two forest types: Igapó and Terra firme in the Amazonian riparian forests. Predictable seasonal flooding poses a significant challenge in Igapó compared to Terra firme environments, with the former presenting higher water column height and longer flooding duration. Our findings suggest that contrasting environmental conditions related to flooding regimes are important drivers of population genetic differentiation and differential gene expression in I. puberulus. Enriched gene ontology terms highlight associations with environmental stresses, such as defence response, water transport, phosphorylation, root development, response to auxin, salicylic acid and oxidative stress. By uncovering key environmental stress response pathways conserved across populations, I. puberulus offers novel genetic insights into the molecular basis of plant reactions to environmental constraints found in flooded areas of this highly biodiverse neotropical ecosystem.

Groundwater is a hidden global keystone ecosystem.

Groundwater is a vital ecosystem of the global water cycle, hosting unique biodiversity and providing essential services to societies. Despite being the largest unfrozen freshwater resource, in a period of depletion by extraction and pollution, groundwater environments have been repeatedly overlooked in global biodiversity conservation agendas. Disregarding the importance of groundwater as an ecosystem ignores its critical role in preserving surface biomes. To foster timely global conservation of groundwater, we propose elevating the concept of keystone species into the realm of ecosystems, claiming groundwater as a keystone ecosystem that influences the integrity of many dependent ecosystems. Our global analysis shows that over half of land surface areas (52.6%) has a medium-to-high interaction with groundwater, reaching up to 74.9% when deserts and high mountains are excluded. We postulate that the intrinsic transboundary features of groundwater are critical for shifting perspectives towards more holistic approaches in aquatic ecology and beyond. Furthermore, we propose eight key themes to develop a science-policy integrated groundwater conservation agenda. Given ecosystems above and below the ground intersect at many levels, considering groundwater as an essential component of planetary health is pivotal to reduce biodiversity loss and buffer against climate change.

Climate-driven shifts in the diversity of plants in the Neotropical seasonally dry forest: Evaluating the effectiveness of protected areas.

Given the current environmental crisis, biodiversity protection is one of the most urgent socio-environmental priorities. However, the effectiveness of protected areas (PAs), the primary strategy for safeguarding ecosystems, is challenged by global climate change (GCC), with evidence showing that species are shifting their distributions into new areas, causing novel species assemblages. Therefore, there is a need to evaluate PAs' present and future effectiveness for biodiversity under the GCC. Here, we analyzed changes in the spatiotemporal patterns of taxonomic and phylogenetic diversity (PD) of plants associated with the Neotropical seasonally dry forest (NSDF) under GCC scenarios. We modeled the climatic niche of over 1000 plant species in five representative families (in terms of abundance, dominance, and endemism) of the NSDF. We predicted their potential distributions in the present and future years (2040, 2060, and 2080) based on an intermediate scenario of shared socio-economic pathways (SSP 3.70), allowing species to disperse to new sites or constrained to the current distribution. Then, we tested if the current PAs network represents the taxonomic and phylogenetic diversities. Our results suggest that GCC could promote novel species assemblages with local responses (communities' modifications) across the biome. In general, models predicted losses in the taxonomic and phylogenetic diversities of all the five plant families analyzed across the distribution of the NSDF. However, in the northern floristic groups (i.e., Antilles and Mesoamerica) of the NSDF, taxonomic and PD will be stable in GCC projections. In contrast, across the NSDF in South America, some cores will lose diversity while others will gain diversity under GCC scenarios. PAs in some NSDF regions appeared insufficient to protect the NSDF diversity. Thus, there is an urgent need to assess how the PA system could be better reconfigured to warrant the protection of the NSDF.

Dada la actual crisis ambiental, la protección de la biodiversidad se presenta como una de las prioridades socio ambientales más urgentes. Sin embargo, la efectividad de las áreas protegidas (AP), la estrategia principal para salvaguardar los ecosistemas, se ve desafiada por el cambio climático global (CCG), con evidencia que muestra que las especies están desplazando sus distribuciones hacia nuevas áreas, provocando conjuntos de especies novedosos. Por lo tanto, es necesario evaluar la efectividad actual y futura de las AP para la biodiversidad bajo el CCG. En este contexto, analizamos cambios en los patrones espacio­temporales de diversidad taxonómica y filogenética de plantas asociadas al bosque estacionalmente seco neotropical (BES) bajo escenarios de CCG. Modelamos el nicho climático de más de 1,000 especies de plantas en cinco familias representativas (en términos de abundancia, dominancia y endemismo) del BES. Pronosticamos sus distribuciones potenciales en los años actuales y futuros (2040, 2060 y 2080) basándonos en un escenario intermedio de trayectorias socioeconómicas compartidas (SSP 3.70), permitiendo que las especies se dispersen a nuevos sitios o estén limitadas a la distribución actual. Luego, evaluamos si la red actual de AP representa las diversidades taxonómicas y filogenéticas. Nuestros resultados sugieren que el CCG podría promover conjuntos de especies novedosos con respuestas locales (modificaciones en las comunidades) en todo el bioma. En general, los modelos pronosticaron pérdidas en las diversidades taxonómicas y filogenéticas de las cinco familias de plantas analizadas en la distribución del BES. Sin embargo, en los grupos florísticos del norte (es decir, Antillas y Mesoamérica) del BSDN, la diversidad taxonómica y filogenética se mantendrá estable en las proyecciones de CCG. En cambio, en toda la región del BES en América del Sur, algunos núcleos perderán diversidad mientras que otros ganarán diversidad bajo escenarios de CCG. Algunas AP en regiones del BES parecen ser insuficientes para proteger la diversidad del bioma. Por lo tanto, es urgente evaluar cómo se podría reconfigurar mejor el sistema de AP para garantizar la protección del BES.

A long-term prospecting study on giant viruses in terrestrial and marine Brazilian biomes.

The discovery of mimivirus in 2003 prompted the search for novel giant viruses worldwide. Despite increasing interest, the diversity and distribution of giant viruses is barely known. Here, we present data from a 2012-2022 study aimed at prospecting for amoebal viruses in water, soil, mud, and sewage samples across Brazilian biomes, using Acanthamoeba castellanii for isolation. A total of 881 aliquots from 187 samples covering terrestrial and marine Brazilian biomes were processed. Electron microscopy and PCR were used to identify the obtained isolates. Sixty-seven amoebal viruses were isolated, including mimiviruses, marseilleviruses, pandoraviruses, cedratviruses, and yaraviruses. Viruses were isolated from all tested sample types and almost all biomes. In comparison to other similar studies, our work isolated a substantial number of Marseillevirus and cedratvirus representatives. Taken together, our results used a combination of isolation techniques with microscopy, PCR, and sequencing and put highlight on richness of giant virus present in different terrestrial and marine Brazilian biomes.

Adaptation to different temperatures results in wing size divergence of the invading species Drosophila nasuta (Diptera: Drosophilidae) in Brazil.

Invasive species threaten biodiversity on a global scale. The success of invasions depends on the species' adaptation to the different environmental conditions of new territories. Studies show that invasive insects present evolutionary changes in wing morphology in areas they are introduced to in response to abiotic conditions. In the last decade, the Asian Drosophila nasuta fly invaded and spread widely throughout Brazil. This insect has preferences for conserved environments and is related to the likely reduction in the abundance of native drosophilids in the Atlantic Forest. Ecological niche modelling analyses showed that rainfall and temperature are the main factors which delimit the geographic distribution of this species. Herein, we verified the existence of significant differences in the wing sizes of D. nasuta in Brazil and evaluated the influence of abiotic factors (rainfall and temperature) on the observed patterns. We conducted 11 measurements on the right-side wings of 240 D. nasuta males collected in the Amazon Forest, Caatinga, Cerrado and Atlantic Forest. Statistical analyses revealed the existence of two groups: one with larger wings, which brought together samples from locations with the lowest temperatures; and one with smaller wings, which corresponded to places with a hotter climate. One explanation for this result is the fact that large wings favour greater heat capture by flies in colder climates, increasing their survival chances in these environments. These rapid evolutionary changes in D. nasuta in this first decade of invasion in Brazil reveal the enormous adaptive potential of this species in this megadiverse country.

Assessing changes in the ecosystem service value in response to land use and land cover dynamics in Malawi.

Land use and land cover (LULC) changes are inevitable outcomes of socioeconomic changes and greatly affect ecosystem services. Our study addresses the critical gap in the existing literature by providing the first comprehensive national analysis of LULC changes and their impacts on ecosystem service values (ESVs) in Malawi. We assessed changes in ecosystem service values (ESVs) in response to LULC changes using the benefit transfer method in ArcGIS 10.6 software. Our findings revealed a significant increase in grasslands, croplands, and urban areas and a notable decline in forests, shrubs, wetlands, and water bodies. Grassland, cropland, and built-up areas expanded by 52%, 1%, and 23.2%, respectively. In contrast, permanent wetlands, barren land, and water bodies declined by 27.6%, 34.3%, and 1%, respectively. The ESV declined from US$90.87 billion in 2001 to US$85.60 billion in 2022, marking a 5.8% reduction. Provisioning services increased by 0.5% while regulating, supporting, and cultural ecosystem service functions declined by 12.2%, 3.16%, and 3.22%, respectively. The increase in provisioning services was due to the expansion of cropland. However, the loss of regulating, supporting, and cultural services was mainly due to the loss of natural ecosystems. Thus, environmental policy should prioritise the conservation and restoration of natural ecosystems to enhance the ESV of Malawi.

Temperature affects the timing and duration of fungal fruiting patterns across major terrestrial biomes.

The Earth's ecosystems are affected by a complex interplay of biotic and abiotic factors. While global temperatures increase, associated changes in the fruiting behaviour of fungi remain unknown. Here, we analyse 6.1 million fungal fruit body (mushroom) records and show that the major terrestrial biomes exhibit similarities and differences in fruiting events. We observed one main fruiting peak in most years across all biomes. However, in boreal and temperate biomes, there was a substantial number of years with a second peak, indicating spring and autumn fruiting. Distinct fruiting peaks are spatially synchronized in boreal and temperate biomes, but less defined and longer in the humid tropics. The timing and duration of fungal fruiting were significantly related to temperature mean and variability. Temperature-dependent aboveground fungal fruiting behaviour, which is arguably also representative of belowground processes, suggests that the observed biome-specific differences in fungal phenology will change in space and time when global temperatures continue to increase.

The Geography of Sexual Conflict: A Synthetic Review.

AbstractSexual conflict is a mechanism of selection driven by the divergent fitness interests between females and males. This disagreement can be great enough to promote antagonistic/defensive traits and behaviors. Although the existence of sexual conflict has been identified in many species, less research has explored the conditions that initially promote sexual conflict in animal mating systems. In previous work in Opiliones, we observed that morphological traits associated with sexual conflict occurred only in species from northern localities. We hypothesized that by shortening and compartmentalizing time periods optimal for reproduction, seasonality represents a geographic condition sufficient to promote sexual conflict. We conducted a systematic review of the literature on reproductive traits and behaviors. Using standardized criteria, we reviewed publications to identify whether subjects occurred in a temperate (high-seasonality) or tropical (low-seasonality) biome. After identifying and adjusting for a publication bias toward temperate research, we identified no significant difference in the strength of sexual conflict between temperate and tropical study systems. A comparison between the distribution of taxa studied in sexual conflict articles and articles focused on general biodiversity indicates that species with conflict-based mating systems more accurately represent the distribution of terrestrial animal species. These findings contribute to ongoing efforts to characterize the origins of sexual conflict as well as life history traits that covary with sexual conflict.

The amazing native Brazilian fruits.

A number of native Brazilian plant species are under exploited by the scientific community, despite the country's precious biodiversity. The vast majority of native Brazilian fruits (NBF) is source of compounds that provide many health benefits and can potentially be used to prevent diseases and formulate high-added value products. This review covers the scientific research over the last decade (2012-2022) on eight NBF, and focuses on information about the production and market panorama, physical description, physicochemical characterization, nutritional composition, their functional value of bioactive compounds and health benefits, as well as the potential for utilizations for each. The studies herein compiled reveal the outstanding nutritional value of these NBF. They are sources of vitamins, fibers, minerals and bioactive compounds that exhibit antioxidant activity, and they contain phytochemicals with anti-inflammatory action, anti-obesity and other functions that bring many health benefits to consumers. NBF can be also used as raw material for multiple products such as nectars, juices, jams, frozen pulps, liquor, among others. The dissemination of knowledge about NBF has fundamental implications worldwide.

Floristic evidence for alternative biome states in tropical Africa.

The idea that tropical forest and savanna are alternative states is crucial to how we manage these biomes and predict their future under global change. Large-scale empirical evidence for alternative stable states is limited, however, and comes mostly from the multimodal distribution of structural aspects of vegetation. These approaches have been criticized, as structure alone cannot separate out wetter savannas from drier forests for example, and there are also technical challenges to mapping vegetation structure in unbiased ways. Here, we develop an alternative approach to delimit the climatic envelope of the two biomes in Africa using tree species lists gathered for a large number of forest and savanna sites distributed across the continent. Our analyses confirm extensive climatic overlap of forest and savanna, supporting the alternative stable states hypothesis for Africa, and this result is corroborated by paleoecological evidence. Further, we find the two biomes to have highly divergent tree species compositions and to represent alternative compositional states. This allowed us to classify tree species as forest vs. savanna specialists, with some generalist species that span both biomes. In conjunction with georeferenced herbarium records, we mapped the forest and savanna distributions across Africa and quantified their environmental limits, which are primarily related to precipitation and seasonality, with a secondary contribution of fire. These results are important for the ongoing efforts to restore African ecosystems, which depend on accurate biome maps to set appropriate targets for the restored states but also provide empirical evidence for broad-scale bistability.

High Trypanosoma cruzi prevalence in armadillo (Zaedyus pichiy; Xenarthra: Chlamyphoridae) populations from Mendoza, Argentina.

Armadillos are considered important reservoir hosts for Trypanosoma cruzi, the causative agent of Chagas disease. The first report of T. cruzi infection in pichis (Zaedyus pichiy), a small armadillo species endemic to central Argentina and Chile, dates back to 1935. However, more recent reports on T. cruzi in this species are scarce. The objective of this study was to assess T. cruzi infection and parasite load in Z. pichiy from Mendoza Province, an area endemic to human Chagas disease. Blood samples were obtained in 2014-2016 from pichis from Lavalle (low Monte), Malargüe (Patagonian steppe), and San Carlos (ecotone) departments, Mendoza Province, Argentina. The detection and quantification of T. cruzi was performed through qPCR amplification using satellite primers. Of the 265 analyzed samples, 201 (76%) were positive for T. cruzi. Parasite loads varied between < 0.1-55.8 parasite-equivalents/mL (par-eq/mL), with a median of 1.1 par-eq/mL in quantifiable samples. The prevalence was similar in Malargüe and Lavalle (85-94%), but significantly lower in pichis from San Carlos (50%). Animals from Lavalle captured after hibernation had significantly higher parasite loads (median 2.0 par-eq/mL). In Malargüe, T. cruzi infection and parasite loads were significantly lower before than after hibernation in 2016. The high prevalence and low median parasite load suggest a chronic and persistent infection of T. cruzi in pichis. Regional differences and a marked increase in precipitation during 2015-2016 could have influenced annual and seasonal infection rates of this vector-borne disease.

Microbial traits determine soil C emission in response to fresh carbon inputs in forests across biomes.

Soil priming is a microbial-driven process, which determines key soil-climate feedbacks in response to fresh carbon inputs. Despite its importance, the microbial traits behind this process are largely undetermined. Knowledge of the role of these traits is integral to advance our understanding of how soil microbes regulate carbon (C) emissions in forests, which support the largest soil carbon stocks globally. Using metagenomic sequencing and 13 C-glucose, we provide unprecedented evidence that microbial traits explain a unique portion of the variation in soil priming across forest biomes from tropical to cold temperature regions. We show that microbial functional profiles associated with the degradation of labile C, especially rapid simple sugar metabolism, drive soil priming in different forests. Genes involved in the degradation of lignin and aromatic compounds were negatively associated with priming effects in temperate forests, whereas the highest level of soil priming was associated with ß-glucosidase genes in tropical/subtropical forests. Moreover, we reconstructed, for the first time, 42 whole bacterial genomes associated with the soil priming effect and found that these organisms support important gene machinery involved in priming effect. Collectively, our work demonstrates the importance of microbial traits to explain soil priming across forest biomes and suggests that rapid carbon metabolism is responsible for priming effects in forests. This knowledge is important because it advances our understanding on the microbial mechanisms mediating soil-climate feedbacks at a continental scale.

Redox traits characterize the organization of global microbial communities.

The structure of biological communities is conventionally described as profiles of taxonomic units, whose ecological functions are assumed to be known or, at least, predictable. In environmental microbiology, however, the functions of a majority of microorganisms are unknown and expected to be highly dynamic and collectively redundant, obscuring the link between taxonomic structure and ecosystem functioning. Although genetic trait-based approaches at the community level might overcome this problem, no obvious choice of gene categories can be identified as appropriate descriptive units in a general ecological context. We used 247 microbial metagenomes from 18 biomes to determine which set of genes better characterizes the differences among biomes on the global scale. We show that profiles of oxidoreductase genes support the highest biome differentiation compared with profiles of other categories of enzymes, general protein-coding genes, transporter genes, and taxonomic gene markers. Based on oxidoreductases' description of microbial communities, the role of energetics in differentiation and particular ecosystem function of different biomes become readily apparent. We also show that taxonomic diversity is decoupled from functional diversity, e.g., grasslands and rhizospheres were the most diverse biomes in oxidoreductases but not in taxonomy. Considering that microbes underpin biogeochemical processes and nutrient recycling through oxidoreductases, this functional diversity should be relevant for a better understanding of the stability and conservation of biomes. Consequently, this approach might help to quantify the impact of environmental stressors on microbial ecosystems in the context of the global-scale biome crisis that our planet currently faces.

Global analysis reveals an environmentally driven latitudinal pattern in mushroom size across fungal species.

Although macroecology is a well-established field, much remains to be learned about the large-scale variation of fungal traits. We conducted a global analysis of mean fruit body size of 59 geographical regions worldwide, comprising 5340 fungal species exploring the response of fruit body size to latitude, resource availability and temperature. The results showed a hump-shaped relationship between mean fruit body size and distance to the equator. Areas with large fruit bodies were characterised by a high seasonality and an intermediate mean temperature. The responses of mutualistic species and saprotrophs were similar. These findings support the resource availability hypothesis, predicting large fruit bodies due to a seasonal resource surplus, and the thermoregulation hypothesis, according to which small fruit bodies offer a strategy to avoid heat and cold stress and therefore occur at temperature extremes. Fruit body size may thus be an adaptive trait driving the large-scale distribution of fungal species.

An integrative synthesis to global amphibian conservation priorities.

Human activities are driving many species to the brink of extinction, and the current distribution of protected areas only weakly alleviates pressure on threatened species. This discrepancy reflects the presence of protected areas on lands available instead of the ecological, evolutionary, or conservation values of species present. Habitat loss consequently continues to impact threatened species, as illustrated by geographic patterns of biodiversity loss for amphibians. Given the need to better align the boundaries of protected areas with at-risk biodiversity, we assessed the importance of various factors for identifying global and biome-level conservation priority areas, specifically for amphibians. We identified, mapped, and ranked areas of critical conservation importance for all amphibian species on earth using a new integrative tool that scores the urgency of conserving each species and location based on a combination of species characteristics and ecoregion-level human impacts. Our integrative approach is novel in that it accounts for likely threats to Data Deficient species, considers the irreplaceability of unique species that are phylogenetically isolated, and addresses the localized conservation implications of species endemicity and projected future human impacts to an ecoregion. For comparison, we also mapped and ranked amphibian biodiversity using species richness and an Evolutionarily Distinct and Globally Endangered (EDGE) score proxy. Our integrative approach predicted key regions for amphibian conservation that were not apparent when using a simple species richness or EDGE score proxy-based approach. Furthermore, by scaling conservation priority scores relative to biome, we identified several temperate and xeric regions of crucial yet overlooked conservation importance for amphibians. Until global amphibian diversity is thoroughly catalogued, we recommend using our integrative scoring approach to set geographic priorities for amphibian habitat protection, while acknowledging that this approach may be complemented by others (e.g., EDGE scores). Our study provides an avenue for avoiding common pitfalls of more simplistic species richness-based approaches for conservation planning, and can be used to improve the future design of protected areas.

Pioneering polyploids: the impact of whole-genome duplication on biome shifting in New Zealand Coprosma (Rubiaceae) and Veronica (Plantaginaceae).

The role of whole-genome duplication (WGD) in facilitating shifts into novel biomes remains unknown. Focusing on two diverse woody plant groups in New Zealand, Coprosma (Rubiaceae) and Veronica (Plantaginaceae), we investigate how biome occupancy varies with ploidy level, and test the hypothesis that WGD increases the rate of biome shifting. Ploidy levels and biome occupancy (forest, open and alpine) were determined for indigenous species in both clades. The distribution of low-ploidy (Coprosma: 2x, Veronica: 6x) versus high-ploidy (Coprosma: 4-10x, Veronica: 12-18x) species across biomes was tested statistically. Estimation of the phylogenetic history of biome occupancy and WGD was performed using time-calibrated phylogenies and the R package BioGeoBEARS. Trait-dependent dispersal models were implemented to determine support for an increased rate of biome shifting among high-ploidy lineages. We find support for a greater than random portion of high-ploidy species occupying multiple biomes. We also find strong support for high-ploidy lineages showing a three- to eightfold increase in the rate of biome shifts. These results suggest that WGD promotes ecological expansion into new biomes.

Dams have varying impacts on fish communities across latitudes: a quantitative synthesis.

Dams are recognised to impact aquatic biodiversity, but the effects and conclusions diverge across studies and locations. By using a meta-analytical approach, we quantified the effects of impoundment on fish communities distributed across three large biomes. The impacts of dams on richness and diversity differed across biomes, with significant declines in the tropics, lower amplitude but similar directional changes in temperate regions, and no changes in boreal regions. Our analyses showed that non-native species increased significantly in tropical and temperate regulated rivers, but not in boreal rivers. In contrast, temporal trajectories in fish assemblage metrics were common across regions, with all biomes showing an increase in mean trophic level position and in the proportion of generalist species after impoundment. Such changes in fish assemblages may affect food web stability and merit closer study. Across the literature examined, predominant mechanisms that render fish assemblages susceptible to impacts from dams were: (1) the transformation of the lotic environment into a lentic environment; (2) habitat fragmentation and (3) the introduction of non-native species. Collectively, our results highlight that an understanding of the regional context and a suite of community metrics are needed to make robust predictions about how fish will respond to river impoundments.

Biome: evolution of a crucial ecological and biogeographical concept.

A biome is a key community ecological and biogeographical concept and, as such, has profited from the overall progress of community ecology, punctuated by two major innovations: shifting the focus from pure pattern description to understanding functionality, and changing the approach from observational to explanatory and, most importantly, from descriptive to predictive. The functional focus enabled development of mechanistic and function-focused predictive and retrodictive modelling; it also shaped the current understanding of the concept of a biome as a dynamic biological entity having many aspects, with deep roots in the evolutionary past, and which is undergoing change. The evolution of the biome concept was punctuated by three synthetic steps: the first synthesis formulated a solid body of theory explaining the ecological and biogeographical meaning of zonality and collated our knowledge on drivers of vegetation patterns at large spatial scales; the second translated this knowledge into effective mechanistic modelling tools, developing further the link between ecosystem functionality and biogeography; and the third (still in progress) is seeking common ground between large-scale ecological and biogeographic phenomena, using macroecology and macroevolutionary research tools.

Past the climate optimum: Recruitment is declining at the world's highest juniper shrublines on the Tibetan Plateau.

Alpine biomes are climate change hotspots, and treeline dynamics in particular have received much attention as visible evidence of climate-induced shifts in species distributions. Comparatively little is known, however, about the effects of climate change on alpine shrubline dynamics. Here, we reconstruct decadally resolved shrub recruitment history (age structure) through the combination of field surveys and dendroecology methods at the world's highest juniper (Juniperus pingii var. wilsonii) shrublines on the south-central Tibetan Plateau. A total of 1,899 shrubs were surveyed at 12 plots located in four regions along an east-to-west declining precipitation gradient. We detected synchronous recruitment with 9 out of 12 plots showing a gradual increase from 1600 to 1900, a peak at 1900-1940, and a subsequent decrease from the 1930s onward. Shrub recruitment was significantly and positively correlated with reconstructed summer temperature from 1600 to 1940, whereas it was negatively associated with temperature in recent decades (1930-2000). Recruitment was also positively correlated with precipitation, except in the 1780-1830 period, when a trend toward wetter climate conditions began. Warming-induced drought limitation has likely reduced the recruitment potential of alpine juniper shrubs in recent decades. Ongoing warming without a simultaneous increase in precipitation is expected to further impair recruitment at the world's highest juniper shrublines and alter the dynamics and competitive balance between woody plant species throughout these alpine biomes.