6 páginas, 2 figuras. ; Global warming leads to shifts in vegetation types in given temperate environments. The fastest species movement is due to the globalized supply and use of exotic plants in gardening and urban landscaping. These standard practices circumvent dispersal limitations and biological and environmental stresses; they have three major global impacts: (i) the enhancement of biological invasions, (ii) the elevation of volatile organic compound emissions and the resulting increase in photochemical smog formation, and (iii) the enhancement of CO2 fixation and water use by gardened plants. These global effects, none of which are currently considered in globalchange scenarios, are increasingly amplified with further warming and urbanization. We urge for quantitative assessment of the global effects of gardening and urban landscaping. ; We acknowledge financial support by the Estonian Ministry of Education and Science (grant SF1090065s07), the Estonian Academy of Sciences, the Spanish Ministry of Education and Science (grants CGL2004–01402/BOS and CGL-2006–04025/BOS), the European Commission RTN 'ISONET' contract MC-RTN-CT-2003–504720, the European Science Foundation 'VOCBAS' program, the Fundació Abertis (2007 grant) and the Catalan government (grant SGR2005–00312). ; Peer reviewed
7 páginas, 2 figuras. ; Physical CO2 diffusion from sub-stomatal cavities to the chloroplasts where photosynthesis takes place is an important limitation of photosynthesis largely neglected in research related to global climate change. This limitation is particularly important in leaves with robust structures such as evergreen sclerophylls. In these leaves, photosynthesis is less sensitive to changes in stomatal openness, which is considered to be the primary limitation of photosynthesis. In this review we state that, because of large limitations in internal diffusion in C3 plants, photosynthesis and the intrinsic efficiency of the use of plant water responds more strongly to elevated levels of CO2 in leaves with more robust structures. This provides an additional explanation for the current apparent expansion of evergreen sclerophylls in many Earth ecosystems, and adds a new perspective to research of the biological effects of increasing atmospheric CO2. ; This study was supported by the Estonian Ministry of Science and Education (grant number SF1090065s07), a collaborative project between the Estonian Academy of Sciences and the Spanish CSIC, the Spanish Government (CGL2006-04025/BOS, CGL2010-17172/BOS and Consolider-Ingenio Montes CSD2008-00040), the CSIC grant PIF08- 006-3 and the Catalan Government grant SGR 2009-458. Research by JF was financed by the Spanish Ministry of Education and Research (Project BFU2008-1072-E/BFI). ; Peer reviewed
60 páginas, 7 figuras, 1 tabla. ; Large uncertainties exist in our knowledge of regional emissions of non-methane biogenic volatile organic compounds (BVOC). We address these uncertainties through a two-pronged approach by compiling a state of the art database of the emissions potentials for 80 European forest species, and by a model assessment and inter-comparison, both at the local and regional scale, under present and projected future climatic conditions. We coupled three contrasting isoprenoid models with the ecophysiological forest model GOTILWA+ to explore the interactive effects of climate, vegetation distribution, and productivity, on leaf and ecosystem isoprenoid emissions, and to consider model behaviour in present climate and under projected future climate change conditions. Hourly, daily and annual isoprene emissions as simulated by the models were evaluated against flux measurements. The validation highlighted a general model capacity to capture gross fluxes but inefficiencies in capturing short term variability. A regional inventory of isoprenoid emissions for European forests was created using each of the three modelling approaches. The models agreed on an average European emissions budget of 1.03 TgC a −1 for isoprene and 0.97 TgC a −1 for monoterpenes for the period 1960–1990, which was dominated by a few species with largest aerial coverage. Species contribution to total emissions depended both on species emission potential and geographical distribution. For projected future climate conditions, however, emissions budgets proved highly model dependent, illustrating the current uncertainty associated with isoprenoid emissions responses to potential future conditions. These results suggest that current model estimates of isoprenoid emissions concur well, but future estimates are highly uncertain. We conclude that development of reliable models is highly urgent, but for the time being, future BVOC emission scenario estimates should consider results from an ensemble of available emission models. ; This study was funded through the GREENCYCLES Marie-Curie Biogeochemistry and Climate Change Research and Training Network (MRTN-CT-2004-512464) supported by the European Commission's Sixth Framework program. Data was supplied by the ALARM (Assessing LArge-scale environmental Risks for biodiversity with tested Methods: GOCE-CT-2003-506675) and ATEAM (Advanced Terrestrial Ecosystem Analysis and Modelling: EVK2-2000-00075) project, from the EU Fifth Framework for Energy, Environment and Sustainable Development and the CSIC-Estonian Academy of Sciences collaborative project. TK acknowledges further support from the CCTAME (Climate Change – Terrestrial Adapta- tion and Mitigation in Europe, FP7 212535) project. JP acknowledges additional funding from the Spanish Ministry of Education and Science project (CGL2006-04025), Consolider Montes (CSD2008-00040), and a Catalan Government project grant (SGR2008-00312) and UN from ¨ the Estonian Science Foundation (Grant 7645) and the Estonian Ministry of Education and Science (grant SF1090065s07). ; Peer reviewed
6 páginas,4 figuras. ; We compared the role of instantaneous temperature and temperature history in the determination of α-pinene emissions in Mediterranean conifer Pinus halepensis that stores monoterpenes in resin ducts, and in Mediterranean broad-leaved evergreen Quercus ilex that lacks such specialized storage structures. In both species, α-pinene emission rates (E) exhibited a significant exponential correlation with leaf temperature and the rates of photosynthetic electron transport (JCO 2 +O 2 ) started to decrease after an optimum at approximately 35 o C. However, there was a higher dependence of E on mean temperature of previous days than on mean temperature of current day for P. halepensis but not for Q. ilex. JCO 2 +O 2 showed a maximum relationship to mean temperature of previous 3 and 5 days for P. halepensis and Q. ilex respectively. We conclude that although the best correlation of emission rates were found for instantaneous foliar temperatures, the effect of accumulated previous temperature con ; Our research on volatile compound emissions has been supported by the funding from the European Science Foundation (Programme VOCBAS), the European Commission Marie Curie research training network ISONET (MC-RTN-CT-2003 504720), the Spanish Government (CGL2006-04025/BOS and ConsoliderIngenio Montes CSD 2008-00040), the Catalan Government (SGR 2009-458), the Spanish National Research council (CSIC-PIF08- 006-3), the Estonian Science Foundation (grant 7645) and the Estonian Ministry of Education and Science (SF1090065s07) ; Peer reviewed
19 páginas, 6 figuras, 2 tablas. ; Leaf elemental and secondary metabolite contents and morphological traits are important measures of time-dependent ecosystem changes. We aimed to test whether plants from older tropical forests have lower nutrient contents and different elemental stoichiometry than plants from younger ecosystems (''soil age'' hypothesis) and whether they had different contents of carbon based secondary compounds (CBSC) and morphological traits as a result of a longer evolution under tropical conditions. We conducted a phylogeny-independent study of the foliar chemical and structural traits in two sets of 86 species each measured in two different-aged tropical forests, a young soil forest in Hawaii and an old soil forest in Borneo. The leaf contents of nutrients and micronutrients tended to be higher in Hawaii than in Borneo but leaf N:P content ratio was not different. The ''soil age'' hypothesis was thus only partially supported by the results indicating that several other factors influence plant elemental content. Total phenolic content was twice larger in Hawaiian than in Bornean plant species. Terpene contents were not different in terpene-containing species but the percentage of species containing terpenes was much higher in Borneo (97%) than in Hawaii (34%) suggesting that the longer time of evolution in Borneo has allowed a more widespread development of very diverse defensive, allelopatic and information relationships of plants with specialist herbivores and other plants. Principal component analyses separated Hawaii and Borneo species on the basis of leaf elemental composition, total phenolics and terpene contents and leaf dry mass per area (LMA). The results collectively support the ''leaf economic spectrum'' and ''carbon excess'' paradigms because in both sets of species and also in the combined set of Borneo and Hawaiian species, there are negative relationships of N content with LMA and total phenolics. The results suggest thus that changes throughout time in N and P availability can be important but do not explain all the variability underlying the evolutionary changes in leaf chemistry and structure in these tropical forests. Other factors determining species biogeochemical niche such as K, Mg or S elemental stoichiometry, leaf economic traits and changes in plant defence and communication strategy are also likely to be involved. ; This research was supported by the Spanish Government projects CGL2006-04025/BOS, CGL2010- 17172, Consolider Ingenio Montes (CSD2008-00040), by the Catalan Government project SGR 2009-458 and by the Estonian Ministry of Education and Research (grant SF1090065s07) ; Peer reviewed
12 páginas, 4 tablas, 2 figuras. ; Aim Alien plant invasion is prominent in the Hawaiian Islands. There are many factors involved in invader success. To date, there is a general lack of information about one of them, which we aim to study here: the terpene emission capacity of both Hawaiian native and alien plants. Location Oahu (Hawaii). Methods We screened 35 alien and 35 native dominant plant species on Oahu Island for monoterpene emissions. The emission rates were measured from field-grown plants under standardized conditions of temperature and quantum flux density in the laboratory. Results The emission rates of total terpenes ranged from 0 µg g−1 h−1 to 55 µg g−1 h−1, and altogether 15 different terpenes were emitted in detectable amounts by the overall set of species. A phylogenetic signal was observed for total terpene emissions. Total terpene emission rates were higher in aliens than in native species (12.8 ± 2.0 vs. 7.6 ± 1.9 µg g−1 h−1, respectively). Main conclusions The greater terpene emission capacity may confer protection against multiple stresses and may partly account for the success of the invasive species, and may make invasive species more competitive in response to new global change-driven combined stresses. These results are consistent with aliens coming from very diverse ecosystems with generally higher biotic and abiotic stress pressures, and having higher nutrient concentrations. On the contrary, these results are not consistent with the 'excess carbon' hypotheses. These results indicate changes in vegetation terpene emissions brought about by alien plant invasions. ; This study was supported by the University of Hawai'i (G. P. Wilder research funds) and the grants from the Spanish Government (CGL2006-04025/BOS and Consolider-Ingenio Montes CSD 2008-00040), the Catalan Government (SGR 2009- 458), the Spanish National Research Council (CSIC-PIF08-006- 3), the Estonian Science Foundation (grant 7645), and the Estonian Ministry of Education and Science (SF1090065s07). ; Peer reviewed
17 páginas, 3 figuras, 4 tablas, 1 apéndice. ; Capacity for terpene production may confer advantage in protection against abiotic stresses such as heat and drought, and also against herbivore and pathogen attack. Plant invasive success has been intense in the Hawaiian islands, but little is known about terpene content in native and alien plant species on these islands. We conducted a screening of leaf terpene concentrations in 35 native and 38 alien dominant plant species on Oahu island. Ten (29%) of the 35 native species and 15 (39%) of the 38 alien species contained terpenes in the leaves. This is the first report of terpene content for the ten native species, and for 10 of the 15 alien species. A total of 156 different terpenes (54 monoterpenes and 102 sesquiterpenes) were detected. Terpene content had no phylogenetic significance among the studied species. Alien species contained significantly more terpenes in leaves (average ± SE=1965±367 μg g −1 ) than native species (830±227 μg g −1 ). Alien species showed significantly higher photosynthetic capacity, N content, and lower Leaf Mass Area (LMA) than native species, and showed higher total terpene leaf content per N and P leaf content. Alien species, thus, did not follow the expected pattern of "excess carbon" in comparison with native species. Instead, patterns were consistent with the "nutrient driven synthesis" hypothesis. Comparing alien and native species, the results also support the modified Evolution of Increased Competitive Ability (EICA) hypothesis that suggests that alien success may be favored by a defense system based on an increase in concentrations of less costly defenses (terpenes) against generalist herbivores. ; This research was supported by grants from the Spanish Government (CGL2006-04025/BOS and Consolider-Ingenio Montes CSD 2008-00040), the Catalan Government (SGR 2009-458), Estonian Science Foundation (grant 7645), and the Estonian Ministry of Education and Science (SF1090065s07) ; Peer reviewed
21 páginas, 6 figuras. ; The rate of constitutive isoprenoid emissions from plants is driven by plant emission capacity under specified environmental conditions (ES, the emission factor) and by responsiveness of the emissions to instantaneous variations in environment. In models of isoprenoid emission, ES has been often considered as intrinsic species-specific constant invariable in time and space. Here we analyze the variations in species-specific values of ES under field conditions focusing on abiotic stresses, past environmental conditions and developmental processes. The reviewed studies highlight strong stress-driven, adaptive (previous temperature and light environment and growth CO2 concentration) and developmental (leaf age) variations in ES values operating at medium to long time scales. These biological factors can alter species-specific ES values by more than an order of magnitude. While the majority of models based on early concepts still ignore these important sources of variation, recent models are including some of the medium- to long-term controls. However, conceptually different strategies are being used for incorporation of these longer-term controls with important practical implications for parameterization and application of these models. This analysis emphasizes the need to include more biological realism in the isoprenoid emission models and also highlights the gaps in knowledge that require further experimental work to reduce the model uncertainties associated with biological sources of variation. ; The authors' studies on BVOC emissions have been funded by the Estonian Ministry of Education and Research (grant SF1090065s07), the Estonian Science Foundation (grant 7645), the US National Science Foundation and the US Environmental Protection Agency, the joint collaborative project between Spanish CSIC and the Estonian Academy of Sciences, the Spanish Government (grants CGL2006-04025/BOS and Consolider-Ingenio Montes CSD2008-00040), the Catalan government (grant SGR2009-458), the Human Frontier Science Programme, the Swedish Research Councils VR and Formas. ; Peer reviewed
16 páginas, 3 tablas, 5 figuras. ; The capacity to produce carbon-based secondary compounds (CBSC), such as phenolics (including tannins) and terpenes as defensive compounds against herbivores or against neighboring competing plants can be involved in the competition between alien and native plant species. Since the Hawaiian Islands are especially vulnerable to invasions by alien species, we compared total phenolic (TP), total tannin (Tta), and total terpene (TT) leaf contents of alien and native plants on Oahu Island (Hawaii). We analyzed 35 native and 38 alien woody plant species randomly chosen among representative current Hawaiian flora. None of these CBSC exhibited phylogenetic fingerprinting. Alien species had similar leaf TP and leaf Tta contents, and 135% higher leaf TT contents compared with native species. Alien plants had 80% higher leaf TT:N leaf content ratio than native plants. The results suggest that apart from greater growth rate and greater nutrient use, alien success in Oahu also may be linked to greater contents of low cost chemical defenses, such as terpenes, as expected in faster-growing species in resource rich regions. The higher TT contents in aliens may counterbalance their lower investment in leaf structural defenses and their higher leaf nutritional quality. The higher TT provides higher effectiveness in deterring the generalist herbivores of the introduced range, where specialist herbivores are absent. In addition, higher TT contents may favor aliens conferring higher protection against abiotic and biotic stressors. The higher terpene accumulation was independent of the alien species origin, which indicates that being alien either selects for higher terpene contents post-invasion, or that species with high terpene contents are pre-adapted to invasiveness. Although less likely, an originally lower terpene accumulation in Hawaiian than in continental plants that avoids the increased attraction of specialist enemies associated to terpenes may not be discarded. ; This research was supported by the University of Hawaii (G. P. Wilder research funds), and grants from the Spanish Government (CGL2006- 04025/BOS, CGL2010-17172 and Consolider-Ingenio Montes CSD2008-00040), the Catalan Government (SGR 2009-458), the Estonian Ministry of Education and Science (grant SF1090065s07), the Spanish National Research council (CSIC-PIF08-006-3), and the Estonian Science Foundation (grant 7645). ; Peer reviewed
61 páginas, 7 figuras, 1 tabla. ; In models of plant volatile isoprenoid emissions, the instantaneous compound emission rate typically scales with the plant's emission capacity under specified environmental conditions, also defined as the emission factor, ES . In the most widely employed plant isoprenoid emission models, the algorithms developed by Guenther and colleagues (1991, 1993), instantaneous variation of the steady-state emission rate is described as the product of ES and light and temperature response functions. When these models are employed in the in atmospheric chemistry modeling community, species-specific ES values and parameter values defining the instantaneous response curves are typically considered as constant. In the current review, we argue that ES is largely a modeling concept, importantly depending on our understanding of which environmental factors affect isoprenoid emissions, and consequently need standardization during ES determination. In particular, there is now increasing consensus that variations in atmospheric CO2 concentration, in addition to variations in light and temperature, need to be included in the emission models. Furthermore, we demonstrate that for less volatile isoprenoids, mono- and sesquiterpenes, the emissions are often jointly controlled by the compound synthesis and volatility, and because of these combined biochemical and physico-chemical properties, specification of ES as a constant value is incapable of describing instantaneous emissions within the sole assumptions of fluctuating light and temperature, as are used in the standard algorithms. The definition of ES also varies depending on the degree of aggregation of ES values in different parameterization schemes (leaf- vs. canopy- or region-level, species vs. plant functional type level), and various aggregated ES schemes are not compatible for different integration models. The summarized information collectively emphasizes the need to update model algorithms by including missing environmental and physico-chemical controls, and always to define ES within the proper context of model structure and spatial and temporal resolution. ; The authors' work on BVOC emissions has been supported by the Estonian Ministry of Education and Research (grant SF1090065s07), the Estonian Science Foundation (grant 7645), the US National Science Foundation and the US Environmental Protection Agency, the join collaborative project between Spanish CSIC and the Estonian Academy of Sciences, the Spanish Government (grants CGL2006-04025/BOS and Consolider-Ingenio BGD 7, 1233–1293, 2010 The emission factor of volatile isoprenoids U. Niinemets et al. ¨ Title Page Abstract Introduction Conclusions References Tables Figures J I J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion Montes CSD2008-00040), the Catalan government (grant SGR2009-458), the Human Frontier Science Programme, the Swedish Research Councils VR and Formas. ; Peer reviewed
15 páginas, 3 figuras, 4 tablas. ; Plant-invasive success is one of the most important current global changes in the biosphere. To understand which factors explain such success, we compared the foliar traits of 41 native and 47 alien-invasive plant species in Oahu Island (Hawaii), a location with a highly endemic flora that has evolved in isolation and is currently vulnerable to invasions by exotic plant species. Foliar traits, which in most cases presented significant phylogenetic signal, i.e. closely related species tended to resemble each other due to shared ancestry, separated invasive from native species. Invasive species had lower leaf mass per area and enhanced capacities in terms of productivity (photosynthetic capacity) and nutrient capture both of macro- (N, P, K) and microelements (Fe, Ni, Cu and Zn). All these differences remain highly significant after removing the effects of phylogenetic history. Alien-invasive species did not show higher efficiency at using limiting nutrient resources, but they got faster leaf economics returns and occupied a different biogeochemical niche, which helps to explain the success of invasive plants and suggests that potential increases in soil nutrient availability might favor further invasive plant success. ; This research was supported by the University of Hawaii (G. P. Wilder research funds), and the grants from the Spanish Government (CGL2006-04025/BOS and Consolider-Ingenio Montes CSD2008-00040), the Catalan Government (SGR 2009-458) and the Estonian Ministry of Education and Science (SF1090065s07) and the join collaborative project between Spanish CSIC and the Estonian Academy of Sciences. ; Peer reviewed
