Alessandra Rodrigues Kozovits

Growing Eremanthus erythropappus in crushed laterite : a promising alternative to topsoil for bauxite-mine revegetation.

Topsoil is the preferred substrate for areas requiring rehabilitation after bauxite mining. However, topsoil is sometimes lacking and so there is a need to test the suitability of other, locally available substrates. In an abandoned bauxite mine in Southeastern Brazil, small patches of native vegetation spontaneously established in shallow depressions over weathered laterite, suggesting that granulometric reduction may have facilitated the establishment of plants. To test this hypothesis, blocks of laterite collected in the area were crushed to simulate texture observed in the vegetation patches. Topsoil collected in a preserved ferruginous field near to the extraction area was also used as a substrate in which Eremanthus erythropappus seedlings, a native woody species, were grown. Seedlings were cultivated without fertilizers in these two substrates and also directly over the exposed and uncrushed laterite. The species proved to be very promising for the revegetation, showing a high survival rate in all substrates. Higher annual growth rates and higher final biomass values were observed in topsoil, but the granulometric reduction of laterite doubled plant growth rate in comparison to the exposed laterite. This result was likely due to the increased availability of essential nutrients to plants and to the improvement in physical conditions for root growth and functioning. Moreover, seedling allometry was not altered by the type of substrate, suggesting that the species was highly tolerant to the new substrate conditions, a fundamental characteristic for success of revegetation of bauxite extraction degraded areas.

Produção, decomposição e qualidade nutricional da serapilheira foliar em uma floresta paludosa de altitude

Florestas paludosas sao ecossistemas com ocorrencia restrita a solos hidromorficos, sujeitos a presenca superficial de agua devido ao afloramento do lencol freatico, onde a diversidade e o estabelecimento da vegetacao dependem de sua adaptabilidade as condicoes de saturacao hidrica e baixa oxigenacao do solo. Este estudo teve como objetivo caracterizar aspectos da ciclagem de N e P em uma floresta paludosa no Parque Estadual do Itacolomi, MG, atraves de mensuracoes da producao, qualidade nutricional e decomposicao da serapilheira foliar durante o periodo de outubro de 2006 a setembro de 2007. A producao anual media de serapilheira nao apresentou variacoes espaciais e foi de 5.7 t ha-1, com pico de producao em setembro. A fracao foliar foi responsavel por 57% da producao total de serapilheira e apresentou concentracoes de N, P e K de 12,6; 0,616 e 3,07 g kg-1, respectivamente. A porcentagem de perda de massa durante a decomposicao de serapilheira foi inversamente correlacionada com o conteudo de agua no solo, variando de 29,2% a 46,2%. A razao N:P da serapilheira foliar sugere que a vegetacao cresca sob limitacao por P. Considerando-se os parâmetros avaliados, a floresta paludosa apresentou um taxa de ciclagem de nutrientes lenta, principalmente em razao da baixa qualidade nutricional da serapilheira e sua lenta decomposicao, em comparacao com valores obtidos em outros estudos em ecossistemas florestais tropicais umidos.

Chapter 19 - Land Use Change, Air Pollution and Climate Change—Vegetation Response in Latin America

Over recent decades, climate changes, especially revealed through alteration in rainfall patterns, with apparent intensification of the dry season, have been documented throughout Latin America. At the same time, this region of the globe has displayed strong economic growth along with profound changes in land use and emission of air pollutants. Long-term studies have shown that functional groups of plants from tropical and sub-tropical rainforests and savannas, the largest and most diverse biomes in the region, present different sensitivities to climate change, increasing CO2 and atmospheric deposition of nitrogen, for example, resulting in evident changes in community structure and dynamics. In general, these factors have led to a reduction in plant diversity. Ozone, though less studied in the region, has been monitored in the major urban centres, and its relation to land use change, as through biomass burning, has become evident. The main results of plant responses to pollutants and climate change are presented.

Germination of native grasses with potential application in the recovery of degraded areas in Quadrilátero Ferrífero, Brazil

As gramineas nativas apresentam potencial para revegetacao de areas degradadas, no entanto, devido ao pouco conhecimento sobre sua biologia, da-se preferencia ao uso de especies exoticas, que podem ser invasoras, afetando assim a biodiversidade local. No intuito de ampliar o conhecimento acerca da propagacao via sementes de especies nativas do Quadrilatero Ferrifero (QF), e desta forma, indicar possiveis candidatas a aplicacao na recuperacao de areas degradadas da regiao, este trabalho objetivou avaliar os padroes germinativos das seguintes gramineas: Andropogon bicornis L.; Andropogon leucostachyus Kunth; Setaria parviflora (Poir.) Kerguelen, Cenchrus brownii Roem. & Schult; Echinolaena inflexa (Poir.). Chase e Apochloa euprepes (Renvoize) Zuloaga & Morrone. As espiguetas (com presenca ou nao das estruturas que envolviam a cariopse, dependendo da especie) foram submetidas aos seguintes tratamentos: T1-controle; T2-umedecimento do substrato com 0,2% de nitrato de potassio, T3-aquecimento a 80 oC por 2 minutos, T4-escarificacao com acido sulfurico (exceto genero Andropogon) e para os generos Andropogon e Setaria, T5-armazenamento a temperatura ambiente e T6-armazenamento sob refrigeracao. Os tratamentos foram realizados em 4 repeticoes de 25 cariopses colocadas para germinar a temperatura de 25 oC e iluminacao constante. Variacao significativa foi observada quando comparadas as quantidades de germinacoes ocorridas entre as semanas, entre os tratamentos e entre as especies. Para o genero Andropogon o tratamento mais eficiente foi T6, seguido por T2 em A. bicornis e T3 em A. leucostachyus. T6 tambem foi o tratamento mais eficiente para S. parviflora, seguido por T5 e T2. C. brownii apresentou resultados proximos sob T1, T2 e T3 (media 39%). E. inflexa e A. euprepes apresentaram altos indices de dormencia que nao foram superadas pelos tratamentos propostos. A. bicornis, A. leucostachyus, S. parviflora e C. brownii apresentaram maiores potenciais de germinacao, sendo possiveis candidatas para recuperacao de areas degradas no QF. No entanto, ainda sao necessarios estudos complementares com os tratamentos mais eficientes e testes de germinacao e estabelecimento em condicoes de campo.

Litterfall dynamics in a iron-rich rock outcrop complex in the southeastern portion of the Iron Quadrangle of Brazil

Ecosystems on cangas (duricrust) present considerable heterogeneity of habitats due to microtopographic variations, soil accumulation and a variety of plant functional groups. Therefore, spatial and temporal ecosystem processes such as litterfall are to be expected to be large, and the absence of a level of productivity represents all the facets of iron-rich landscapes. We investigated litterfall in a iron-rich rock complex in the Iron Quadrangle of Brazil, with habitats formed on different evolutionary stages of the soil, resulting in a gradient of biomass, canopy cover and community structure. The measurements were made in open field areas, dominated by herb-shrub vegetation and interspersed with islands of dense vegetation in which there were individual trees, as well as in areas of semideciduous forest. The litterfall, especially that of leaf litter, followed the gradient of woody cover and was approximately two times greater in the forest formation. However, the spatial and temporal variations in deposition were greatest in the herb-shrub areas and least in the semideciduous forest area, intermediate values being obtained for the tree island areas. The peaks in litterfall also varied among habitats, occurring in some periods of the rainy season and during the transition from rainy to dry in the herb-shrub and tree island areas, whereas they occurred at the end of the dry season in the semideciduous forest area. The results show significant differences in the patterns of litterfall among different physiognomies within the same iron-rich rock complex, indicating the need for expanded studies, focusing on the flow of matter and energy in such environments.

Influence of soil texture on nutrients and potentially hazardous elements in Eremanthus erythropappus

Understanding the factors that control uptake rates and allocation of chemical elements among plant organs is a fundamental prerequisite to improve phytostabilization techniques of hazardous elements in contaminated areas. The present study shows evidence that different substrate textures (coarse and fine laterite) do not significantly change the partitioning of root and shoot dry biomass and with few exceptions, do not significantly affect the final average concentration of elements in Eremanthus erythropappus, but change the root:shoot allocation of both essential nutrients and elements potentially toxic to biota. Growth on coarse laterite resulted in significant higher K (30%), Mg (34%), P (25%), S (32%), Cu (58%), and Na (43%) concentrations in roots and lower Cd concentration (29%). In shoots, coarse laterite led to reduction in K, Fe, Al, and Cr and increase in Na and Sr concentrations. Changes in element allocation could be, in part, a result of differences in the water availability of substrates. Matric potential in coarse laterite was significantly lower in at least 47% of the days analyzed throughout the year. Changes in element phytoextraction or phytostabilization potential could influence the efficiency of rehabilitation projects in areas degraded by mining activities.

CRESCIMENTO DE ESPÉCIES NATIVAS DE CERRADO E DE Vetiveria zizanioides EM PROCESSOS DE REVEGETAÇÃO DE VOÇOROCAS

Rates of seed germination, plant survival and growth, as measured in the present study, are essential parameters to characterize the biological potential of species for the restoration of degraded areas. The lack of knowledge about these aspects in native species has justified the use of exotic plants in Brazilian gullies revegetation. However, especially in places subject to highly seasonal climate and on oligotrophic soils, exotic species do not always perform well, leading to revegetation failure or significantly increasing the cultivation care needs. To improve the knowledge concerning to the biological potencial of cerrado native species and of an exotic grass which has been used for erosion contention, in the present study, seedlings and clumps of native cerrado species, Cratylia argentea (Desv.) Kuntze and Echinolaena inflexa (Poir.) Chase, and of the exotic grass Vetiveria zizanioides (L.) Nash, were transferred to a gully colluvium in Ouro Preto, Minas Gerais state, where they remained during the dry season of 2010 without application of fertilizers or irrigation. In randomized block design, plots of 1 x 1 m received four planting treatments: clumps of Echinolaena inflexa or Vetiveria zizanioides, and clumps of these grasses intercropped with the legume Cratylia argentea. All grasses and 73% of the legume seedlings survived. As expected, the green cover of Echinolaena inflexadecreased throughout the dry season, however, showing regrowth after the first rains. Leaf area of Vetiveria zizanioides remained active and grew significantly in the period. Cratylia argentea showed high rates of germination and growth; however, nodulation occurred in only two individuals. Thus, there was no influence of the legume on grasses growth. Results indicate that both native species and the exotic grass tested are potential successful plants for gullies replanting. Plants survived and grew on low nutrient substrate and during the critical period of drought without any fertilizer or irrigation application.

Biological reactions of forests to climate change and air pollution

From May 18 through 26, 2012, the conference on ‘‘Biological Reactions of Forests to Climate Change and Air Pollution’’ was held in Kaunas/Lithuania under the auspices of the International Union of Forest Research Organizations (IUFRO), represented by the Working Group 7.01.00 (chaired by Andrzej Bytnerowicz and Elena Paoletti) on ‘‘Impacts of Air Pollution and Climate Change on Forest Ecosystems.’’ Local organizers were Algirdas Augustaitis and Ingrida Augustaitiene from the Aleksandras Stulginskis University. More than 200 scientists from 34 countries gathered at the University Campus to share the current state of knowledge and discuss scientific gaps in the understanding of the concerted action of climate change and air pollution on forest ecosystems and their responsiveness (Augustaitis et al. 2014). A number of publications were selected for this Special Topic, which originated from presentations relating to ‘‘Mechanisms of Action and Indicator Development’’—being the title of one of the sessions and also of Research Group 7.01.02 chaired by the three first authors of this editorial. In the following, an overview will briefly be presented on the scope of the conference and the focus of the selected publications. The long-standing commitment of IUFRO Working Group 7.01.00 is to foster international cooperation between scientists, policy makers and governmental institutions based on conferences that are to share the current state of knowledge on climate change and air pollution effects on forest trees and ecosystems. This implies clarification of underlying mechanisms and harmonization of strategies for risk mitigation. Air pollution has attained attention as a stress component which is intrinsically woven with the phenomena of climate and global change, recognizing extensive forest burning, in particular, as a means of land-use change (Matyssek et al. 2014). On such grounds, the need and significance at the forest tree and ecosystem scale have become evident for long-term ecological research on the main challenge in understanding, which is the process-based, cause–effect-related clarification of system responsiveness to a changing and polluted environment, comprising capacities for risk mitigation through mechanisms of stress acclimation and adaptation. This challenge requires the exploration of scenarios that integrate biotic interactions, e.g., such of competition and diseases as well as belowground agents as modifiers of climate change and air pollution effects. Indispensible, in addition, is the initiation of comprehensive systems biology that needs to extend beyond the molecular level of metabolic control toward the integration of the (eco-)physiological process level. This means that an ‘‘ecosystems biology’’ is required for establishing mechanistic understanding of nonlinearities and emergent synergies in system behavior (Matyssek et al. 2012a). It was concluded that at the present stage, the step needs to be taken from filling gaps in evidence toward reaching integration of knowledge across spatio-temporal scales. R. Matyssek (&) Ecophysiology of Plants, Technische Universität München, Freising, Weihenstephan, Germany e-mail: matyssek@wzw.tum.de

Oxidant-antioxidant balance and tolerance against oxidative stress in pioneer and non-pioneer tree species from the remaining Atlantic Forest

The extensive land occupation in Southeast Brazil has resulted in climatic disturbances and environmental contamination by air pollutants, threatening the Atlantic forest remnants that still exist in that region. Based on previous results, we assumed that pioneer tree species are potentially more tolerant against environmental oxidative stress than non-pioneer tree species from that Brazilian biome. We also assumed that reactive oxygen species (ROS) are accumulated in higher proportions in leaves of non-pioneer trees, resulting in changes in the oxidant-antioxidant balance and in more severe oxidative damage at the cellular level than in the leaves of pioneer trees. We tested these hypotheses by establishing the relationship between oxidants (ROS), changes in key antioxidants (among enzymatic and non-enzymatic compounds) and in a lipid peroxidation derivative in their leaves, as well as between ROS accumulation and oscillations in environmental stressors, thus permitting to discuss comparatively for the first time the oxidant-antioxidant balance and the tolerance capacity of tree species of the Atlantic Forest in SE Brazil. We confirmed that the non-pioneer tree species accumulated higher amounts of superoxide and hydrogen peroxide in palisade parenchyma and epidermis, showing a less effective antioxidant metabolism than the pioneer species. However, the non-pioneer species showed differing capacities to compensate the oxidative stress in both years of study, which appeared to be associated with the level of ROS accumulation, which was evidently higher in 2015 than in 2016. We also applied exploratory multivariate statistics, which revealed that the oscillations in these biochemical leaf responses in both functional groups coincided with the oscillations in both climatic conditions and air pollutants, seemingly showing that they had acclimated to the stressful oxidative environment observed and may perpetuate in the disturbed forest remnants located in SE Brazil.

Strategies of leaf water uptake based on anatomical traits

The ability of leaves to absorb fog water can positively contribute to the water and carbon balance of plants in montane ecosystems, especially in periods of soil water deficit. However, the ecophysiological traits and mechanisms responsible for variations in the speed and total water absorption capacity of leaves are still poorly known. This study investigated leaf anatomical attributes of seven species occurring in seasonal tropical high-altitude ecosystems (rocky outcrop and forest), which could explain differences in leaf water uptake (LWU) capacities. We tested the hypothesis that different sets of anatomical leaf attributes will be more marked in plant individuals living under these contrasting environmental conditions. Anatomical variations will affect the initial rate of water absorption and the total storage capacity, resulting in different strategies for using the water supplied by fog events. Water absorption by leaves was inferred indirectly, based on leaf anatomical structure and visual observation of the main access routes (using an apoplastic marker), the diffusion of water through the cuticle, and non-glandular or glandular trichomes in all species. The results suggest that three LWU strategies coexist in the species studied. The different anatomical patterns influenced the speed and maximum LWU capacity. The three LWU strategies can provide different adaptive advantages to adjust to temporal and spatial variations of water availability in these tropical high-altitude environments.