No abstract

The importance of biodiversity in supporting ecosystem functioning is generally well accepted. However, most evidence comes from small-scale studies, and scaling-up patterns of biodiversity-ecosystem functioning (B-EF) remains challenging, in part because the importance of environmental factors in shaping B-EF relations is poorly understood. Using a forest research platform in which 26 ecosystem functions were measured along gradients of tree species richness in six regions across Europe, we investigated the extent and the potential drivers of context dependency of B-EF relations. Despite considerable variation in species richness effects across the continent, we found a tendency for stronger B-EF relations in drier climates as well as in areas with longer growing seasons and more functionally diverse tree species. The importance of water availability in driving context dependency suggests that as water limitation increases under climate change, biodiversity may become even more important to support high levels of functioning in European forests.

Many experiments have shown that local biodiversity loss impairs the ability of ecosystems to maintain multiple ecosystem functions at high levels (multifunctionality). In contrast, the role of biodiversity in driving ecosystem multifunctionality at landscape scales remains unresolved. We used a comprehensive pan-European dataset, including 16 ecosystem functions measured in 209 forest plots across six European countries, and performed simulations to investigate how local plot-scale richness of tree species (α-diversity) and their turnover between plots (β-diversity) are related to landscape-scale multifunctionality. After accounting for variation in environmental conditions, we found that relationships between α-diversity and landscape-scale multifunctionality varied from positive to negative depending on the multifunctionality metric used. In contrast, when significant, relationships between β-diversity and landscape-scale multifunctionality were always positive, because a high spatial turnover in species composition was closely related to a high spatial turnover in functions that were supported at high levels. Our findings have major implications for forest management and indicate that biotic homogenization can have previously unrecognized and negative consequences for large-scale ecosystem multifunctionality.Additional co-authors: Damien Bonal, Olivier Bouriaud, Helge Bruelheide, Filippo Bussotti, Monique Carnol, Bastien Castagneyrol, Yohan Charbonnier, David Anthony Coomes, Andrea Coppi, Cristina C. Bastias, Seid Muhie Dawud, Hans De Wandeler, Timo Domisch, Leena Finér, Arthur Gessler, André Granier, Charlotte Grossiord, Virginie Guyot, Stephan Hättenschwiler, Hervé Jactel, Bogdan Jaroszewicz, Tommaso Jucker, Julia Koricheva, Harriet Milligan, Sandra Mueller, Bart Muys, Diem Nguyen, Martina Pollastrini, Sophia Ratcliffe, Karsten Raulund-Rasmussen, Federico Selvi, Jan Stenlid, Fernando Valladares, Lars Vesterdal, Dawid Zielínski, and Markus Fische

There is considerable evidence that biodiversity promotes multiple ecosystem functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. However, the mechanisms underlying this relationship are poorly understood, especially in natural ecosystems. We develop a novel approach to partition biodiversity effects on multifunctionality into three mechanisms and apply this to European forest data. We show that throughout Europe, tree diversity is positively related with multifunctionality when moderate levels of functioning are required, but negatively when very high function levels are desired. For two well-known mechanisms, ‘complementarity' and ‘selection', we detect only minor effects on multifunctionality. Instead a third, so far overlooked mechanism, the ‘jack-of-all-trades' effect, caused by the averaging of individual species effects on function, drives observed patterns. Simulations demonstrate that jack-of-all-trades effects occur whenever species effects on different functions are not perfectly correlated, meaning they may contribute to diversity–multifunctionality relationships in many of the world's ecosystems.

The Boraginales are now universally accepted as monophyletic and firmly placed in Lamiidae. However, a consensus about familial classification has remained elusive, with some advocating recognition of a single, widely variable family, and others proposing recognition of several distinct families. A consensus classification is proposed here, based on recent molecular phylogenetic studies, morphological characters, and taking nomenclatural stability into consideration. We suggest the recognition of eleven, morphologically well-defined and clearly monophyletic families, namely the Boraginaceae s.str., Codonaceae, Coldeniaceae fam. nov., Cordiaceae, Ehretiaceae, Heliotropiaceae, Hoplestigmataceae, Hydrophyllaceae, Lennoaceae, Namaceae, and Wellstediaceae. Descriptions, synonomy, a taxonomic key, and a list of genera for these eleven families are provided, including the new family Coldeniaceae (monogeneric) and Namaceae (segregated from Hydrophyllaceae and comprising Nama, Eriodictyon, Turricula, and Wigandia), the latter necessitating a revised circumscription of a more morphologically coherent Hydrophyllaceae. Keywords angiosperms; Boraginaceae; Boraginales; classification; family; plant taxonomy Boraginales Working Group • Families of Boraginales 503Version of Record TAXON 65 (3) • June 2016: 502-522 Boraginaceae in this traditional sense (Candolle, 1845; Bentham & Hooker, 1876;Gürke, 1893;Engler, 1898;Pilger & Krause, 1915) were subdivided into five subfamilies, namely Boraginoideae, Cordioideae, Ehretioideae, Heliotropioideae and Wellstedioideae. In pre-molecular times most scientists accepted this circumscription of Boraginaceae (e.g., Chadefaud & Emberger, 1960;Melchior, 1964b;Takhtajan, 1980Takhtajan, , 1997 Cronquist, 1981 Cronquist, , 1988Thorne, 1992), although some authors recognized one or the other subfamily at the family level. For example, Svensson (1925) andDi Fulvio (1978) removed Cordioideae, Heliotropioideae and Ehretioideae to Heliotropi aceae based on embryological studies, while Merxmüller (1960), Dahlgren (1980), and Takhtajan (1987) treated Wellstedioideae at the family level as Wellstediaceae. Conversely, Hoplestigmataceae, Hydrophyllaceae, and Lennoaceae were generally accepted as distinct families. However, the close relationships of these taxa to traditional Boraginaceae has been widely acknowledged by several authors (e.g., Jussieu, 1789; Baillon, 1891;Peter, 1893;Svensson, 1925; Chadefaud & Emberger, 1960; Melchior, 1964a, c;Takhtajan, 1980; Cronquist, 1981 Cronquist, , 1988. For example, Baillon (1891) defined the Boraginaceae as comprising nine series, which included both Boraginaceae and Hydrophyllaceae in their traditional circumscriptions. Chadefaud & Emberger (1960) considered Boraginaceae, Hoplestigmataceae, Hydrophyllaceae, and Lennoaceae to form a natural group within the order Tubiflorales. Takhtajan (1980) included these same families in the suborder Boraginineae.On the other hand, three groups historically associated to Boraginaceae have been clearly sho...