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1. Understanding the importance of biotic interactions in driving the distribution and abundance of species is a central goal of plant ecology. Early vascular plants likely colonized land occupied by biocrusts — photoautotrophic, surface-dwelling soil communities comprised of cyanobacteria, bryophytes, lichens and fungi — suggesting biotic interactions between biocrusts and plants have been at play for some 2,000 million years. Today, biocrusts coexist with plants in dryland ecosystems worldwide, and have been shown to both facilitate or inhibit plant species performance depending on ecological context. Yet, the factors that drive the direction and magnitude of these effects remain largely unknown. 2. We conducted a meta-analysis of plant responses to biocrusts using a global data-set encompassing 1,004 studies from six continents. 3. Meta-analysis revealed there is no simple positive or negative effect of biocrusts on plants. Rather, plant responses differ by biocrust composition and plant species traits and vary across plant ontogeny. Moss-dominated biocrusts facilitated, while lichen-dominated biocrusts inhibited overall plant performance. Plant responses also varied among plant functional groups: C₄ grasses received greater benefits from biocrusts compared to C₃ grasses, and plants without N-fixing symbionts responded more positively to biocrusts than plants with N-fixing symbionts. Biocrusts decreased germination but facilitated growth of non-native plant species. 4. Synthesis. Results suggest that interspecific variation in plant responses to biocrusts, contingent on biocrust type, plant traits, and ontogeny can have strong impacts on plant species performance. These findings have important implications for understanding biocrust contributions to plant productivity and community assembly processes in ecosystems worldwide.

Trees growing on shallow rocky soils must have exceptional adaptations when underlying weathered bedrock has no deep fractures for water storage. Under semiarid conditions, hydrology of shallow soils is expected to decouple from plant hydrology, as soils dry out as a result of rapid evaporation and competition for water increases between coexisting tree species. Gas exchange and plant–water relations were monitored for 15 months for Pinus cembroides and Quercus potosina tree species in a tropical semiarid forest growing on c. 20-cm-deep soils over impermeable volcanic bedrock. Soil and leaf water potential maintained a relatively constant offset throughout the year in spite of high intra-annual fluctuations reaching up to 5 MPa. Thus, hydrology of shallow soils did not decouple from hydrology of trees even in the driest period. A combination of redistribution mechanisms of water stored in weathered bedrock and hypodermic flow accessible to oak provided the source of water supply to shallow soils, where most of the actively growing roots occurred. This study demonstrates a unique geoecohydrological mechanism that maintains a tightly coupled hydrology between shallow rocky soils and trees, as well as species coexistence in this mixed forest, where oak facilitates water access to pine.

Soil bacteria and fungi play key roles in the functioning of terrestrial ecosystems, yet our understanding of their responses to climate change lags significantly behind that of other organisms. This gap in our understanding is particularly true for drylands, which occupy ∼41% of Earth´s surface, because no global, systematic assessments of the joint diversity of soil bacteria and fungi have been conducted in these environments to date. Here we present results from a study conducted across 80 dryland sites from all continents, except Antarctica, to assess how changes in aridity affect the composition, abundance, and diversity of soil bacteria and fungi. The diversity and abundance of soil bacteria and fungi was reduced as aridity increased. These results were largely driven by the negative impacts of aridity on soil organic carbon content, which positively affected the abundance and diversity of both bacteria and fungi. Aridity promoted shifts in the composition of soil bacteria, with increases in the relative abundance ofChloroflexiand α-Proteobacteriaand decreases inAcidobacteriaandVerrucomicrobia. Contrary to what has been reported by previous continental and global-scale studies, soil pH was not a major driver of bacterial diversity, and fungal communities were dominated byAscomycota. Our results fill a critical gap in our understanding of soil microbial communities in terrestrial ecosystems. They suggest that changes in aridity, such as those predicted by climate-change models, may reduce microbial abundance and diversity, a response that will likely impact the provision of key ecosystem services by global drylands.

The complexity of sustainability challenges and the need for transformative change have prompted the exploration of novel approaches for knowledge co‐generation and decision‐making. This calls for integrative assessment methods that meaningfully include and represent diverse knowledge systems, capturing multiple values, needs and interests as a strong basis for decision‐making. We present a case study from a dryland biosphere reserve that details our experience in co‐designing participatory monitoring of a sand dune dominated landscape. We wove together local ranchers' and scientific knowledge systems to co‐create an integrated index for monitoring rangeland multifunctionality. This paper focuses on the process of co‐creation and how it can be used to develop actionable knowledge that is essential for tackling the complex challenges faced by extensively managed social‐ecological systems. We demonstrate the significance of establishing a collaborative partnership between interdisciplinary researchers and local ranchers. This partnership was crucial for developing a profound shared understanding of the complex ecohydrological function of the sand dune landscape and its relationship with livestock production, which enabled the co‐creation of the Integrated Rangeland Multifunctionality Index (IRMI). The co‐production process ensured equitable inclusion of diverse knowledge systems in management decision‐making. Our proposed participatory research method is not about simply adding or comparing different knowledge systems. Instead, it is a method for generating integrated quantitative indices based on a shared understanding of rangeland health. This approach can be applied to other social‐ecological systems more broadly, to promote ecosystem health while accounting for future changes in climate, land tenure and market conditions. Read the free Plain Language Summary for this article on the Journal blog. Resumen La complejidad de los retos de la sostenibilidad y la necesidad de un cambio transformador han impulsado la exploración de enfoques novedosos para la cogeneración de conocimientos y la toma de decisiones. Esto requiere métodos de evaluación integradores que incluyan y representen de manera significativa diversos sistemas de conocimiento, captando múltiples valores, necesidades e intereses como base sólida para la toma de decisiones. Presentamos un estudio de caso en una Reserva de la Biosfera en una zona árida que detalla nuestra experiencia en el diseño conjunto de un sistema de monitoreo participativo de un paisaje dominado por dunas de arena. Tejimos los sistemas de conocimiento de ganaderos locales y de científicos para crear conjuntamente un índice integrado para monitorear la multifuncionalidad de los agostaderos. Este artículo se centra en el proceso de creación conjunta y en cómo puede utilizarse para desarrollar conocimientos prácticos que son esenciales para abordar los complejos retos a los que se enfrentan los sistemas socio‐ecológicos gestionados de forma extensiva. Demostramos la importancia de establecer una colaboración entre investigadores interdisciplinarios y ganaderos locales. Esta colaboración fue crucial para desarrollar una comprensión profunda y compartida de la compleja función ecohidrológica del paisaje de dunas de arena y su relación con la producción ganadera, lo que permitió la creación conjunta del Índice Integrado de Multifuncionalidad de los Agostadero (IRMI por sus siglas en inglés). El proceso de coproducción garantizó la inclusión equitativa de diversos sistemas de conocimiento en la toma de decisiones de manejo. El método de investigación participativa que proponemos no consiste simplemente en añadir o comparar diferentes sistemas de conocimiento. Se trata, más bien, de un método para generar índices cuantitativos integrados basados en una comprensión compartida de la salud de los agostaderos. Este enfoque puede aplicarse de manera más amplia a otros sistemas socio‐ ecológicos, con el fin de promover la salud de los ecosistemas y tener en cuenta los cambios futuros en el clima, la tenencia de la tierra y las condiciones del mercado. Read the free Plain Language Summary for this article on the Journal blog.

In this millennium, global drylands face a myriad of problems that present tough research, management, and policy challenges. Recent advances in dryland development, however, together with the integrative approaches of global change and sustainability science, suggest that concerns about land degradation, poverty, safeguarding biodiversity, and protecting the culture of 2.5 billion people can be confronted with renewed optimism. We review recent lessons about the functioning of dryland ecosystems and the livelihood systems of their human residents and introduce a new synthetic framework, the Drylands Development Paradigm (DDP). The DDP, supported by a growing and well-documented set of tools for policy and management action, helps navigate the inherent complexity of desertification and dryland development, identifying and synthesizing those factors important to research, management, and policy communities.

Mexico is one of the most biodiverse countries in the world, with an important proportion of endemism mainly because of the convergence of the Nearctic and Neotropical biogeographic regions, which generate great diversity and species turnover at different spatial scales. However, most of our knowledge of the Mexican ant biota is limited to a few well‐studied taxa, and we lack a comprehensive synthesis of ant biodiversity information. For instance, most of the knowledge available in the literature on Mexican ant fauna refers only to species lists by states, or is focused on only a few regions of the country, which prevents the study of several basic and applied aspects of ants, from diversity and distribution to conservation. Our aims in this data paper are therefore (1) to compile all the information available regarding ants across the Mexican territory, and (2) to identify major patterns in the gathered data set and geographic gaps in order to direct future sampling efforts. All records were obtained from raw data, including both unpublished and published information. After exhaustive filtering and updating information and synonyms, we compiled a total of 21,731 records for 887 ant species distributed throughout Mexico from 1894 to 2018. These records were concentrated mainly in the states of Chiapas (n = 6,902, 32.76%) and Veracruz de Ignacio de la Llave (n = 4,329, 19.92%), which together comprise half the records. The subfamily with the highest number of records was Myrmicinae (n = 10,458 records, 48.12%), followed by Formicinae (n = 3,284, 15.11%) and Ponerinae (n = 1,914, 8.8%). Most ant records were collected in the Neotropical region of the country (n = 12,646, 58.19%), followed by the Mexican transition zone (n = 5,237, 24.09%) and the Nearctic region (n = 3,848, 17.72%). Native species comprised 95.46% of the records (n = 20,745). To the best of our knowledge, this is the most complete data set available to date in the literature for the country. We hope that this compilation will encourage researchers to explore different aspects of the population and community research of ants at different spatial scales, and to aid in the establishment of conservation policies and actions. There are no copyright restrictions. Please cite this data paper when using its data for publications or teaching events.

The wood of the pau-brasil tree (Paubrasilia echinata Lam., formerly Caesalpinia echinata Lam.) is used worldwide as raw material for the construction of high-quality bows for string instruments. Alternative tree species are rarely accepted by professional musicians, or by bow and violin makers. Historical overexploitation of this endemic species in the Brazilian Atlantic Forest biome (Mata Atlântica), a global biodiversity hotpot including UNESCO World Natural Heritage Sites, and illegal trade have caused drastic declines in its natural abundance. Pau-brasil is now classified as an endangered species and listed in Appendix II of the Convention on International Trade in Endangered Species. Traditional bow-making craftsmanship, an intangible cultural heritage, depends heavily on the high-quality pau-brasil wood. This complex situation presents unprecedented cross-continental transdisciplinary challenges. In order to target the protection of this coupled natural/cultural heritage, this work frames and examines the pau-brasil/bow-making cultural-ecological system as a complex telecoupled system linked by cultural ecosystem services provided by the pau-brasil, as well as the relationships and cultural exchanges among key actors. Using historical trajectory analysis, we identify past, present, and potential future trigger events, key drivers, and key system variables that explain the dynamics, feedback, and resilience of this complex multi-dimensional system. Furthermore, with a cross-scale social and power relations analysis, we examine the level of dependencies and influences of contemporary key actors on the ecosystem services provided by the pau-brasil and their interconnections, in order to ultimately identify their level of disadvantage regarding the pau-brasil. Finally, we discuss the potential of this novel cultural-ecological system approach to (i) interlink science, nature, and art, (ii) reconcile the currently competing protection aims of natural and cultural heritage elements, and (iii) provide future trajectories regarding the resilience and sustainable development of this pau-brasil/bow-making cultural-ecological system. We advocate for this novel path forward toward sustainable transformation of complex cultural-ecological systems urgently needed to navigate our increasingly telecoupled world.

A classical symphony orchestra consists of up to 29 musical instruments manufactured from up to 758 distinct natural materials. The interrelationships between the extraction of raw materials for instrument making, the international trade conditions, and the protection status of endangered species and their ecosystems are highly complex and have yet to be sufficiently scientifically examined. However, rapidly progressing climate and ecological change call for sustainable solutions. To address this challenging task, we present MusEcology , a new interactive decision support system based on visualizations. The interactive visualizations offer entry points for users of various backgrounds to explore the interrelationships between musical instruments, natural resources and ecosystems. The tool’s fundamental objectives are to guarantee that the (1) data processing correlates related data resources, that (2) visual interfaces and interaction schemes encourage new interdisciplinary research on complex systems interactions, and that (3) high-level decision-making is supported to identify alternative pathways towards sustainable instrument making.

Aim: Geographical, climatic and soil factors are major drivers of plant beta diversity, but their importance for dryland plant communities is poorly known. The aim of this study was to: (1) characterize patterns of beta diversity in global drylands; (2) detect common environmental drivers of beta diversity; and (3) test for thresholds in environmental conditions driving potential shifts in plant species composition. Location: Global. Methods: Beta diversity was quantified in 224 dryland plant communities from 22 geographical regions on all continents except Antarctica using four complementary measures: the percentage of singletons (species occurring at only one site); Whittaker's beta diversity, β(W); a directional beta diversity metric based on the correlation in species occurrences among spatially contiguous sites, β(R²); and a multivariate abundance-based metric, β(MV). We used linear modelling to quantify the relationships between these metrics of beta diversity and geographical, climatic and soil variables. Results: Soil fertility and variability in temperature and rainfall, and to a lesser extent latitude, were the most important environmental predictors of beta diversity. Metrics related to species identity [percentage of singletons and β (W)] were most sensitive to soil fertility, whereas those metrics related to environmental gradients and abundance [(β(R²) and β(MV)] were more associated with climate variability. Interactions among soil variables, climatic factors and plant cover were not important determinants of beta diversity. Sites receiving less than 178 mm of annual rainfall differed sharply in species composition from more mesic sites (> 200 mm). Main conclusions: Soil fertility and variability in temperature and rainfall are the most important environmental predictors of variation in plant beta diversity in global drylands. Our results suggest that those sites annually receiving c. 178 mm of rainfall will be especially sensitive to future climate changes. These findings may help to define appropriate conservation strategies for mitigating effects of climate change on dryland vegetation.

AIMS: Climate and human impacts are changing the nitrogen (N) inputs and losses in terrestrial ecosystems. However, it is largely unknown how these two major drivers of global change will simultaneously influence the N cycle in drylands, the largest terrestrial biome on the planet. We conducted a global observational study to evaluate how aridity and human impacts, together with biotic and abiotic factors, affect key soil variables of the N cycle. LOCATION: Two hundred and twenty‐four dryland sites from all continents except Antarctica widely differing in their environmental conditions and human influence. METHODS: Using a standardized field survey, we measured aridity, human impacts (i.e. proxies of land uses and air pollution), key biophysical variables (i.e. soil pH and texture and total plant cover) and six important variables related to N cycling in soils: total N, organic N, ammonium, nitrate, dissolved organic:inorganic N and N mineralization rates. We used structural equation modelling to assess the direct and indirect effects of aridity, human impacts and key biophysical variables on the N cycle. RESULTS: Human impacts increased the concentration of total N, while aridity reduced it. The effects of aridity and human impacts on the N cycle were spatially disconnected, which may favour scarcity of N in the most arid areas and promote its accumulation in the least arid areas. MAIN CONCLUSIONS: We found that increasing aridity and anthropogenic pressure are spatially disconnected in drylands. This implies that while places with low aridity and high human impact accumulate N, most arid sites with the lowest human impacts lose N. Our analyses also provide evidence that both increasing aridity and human impacts may enhance the relative dominance of inorganic N in dryland soils, having a negative impact on key functions and services provided by these ecosystems.