Can guava monocultures (Psidium guajava L.) function as refuge for bird conservation?

Agricultural intensification negatively affects bird communities, and the response of birds to these changes varies from those that survive and increase their populations (disturb-tolerant species) to those that cannot adapt to new conditions and are regionally extinct (disturb-sensitive species). Thus, the present study sought to investigate the bird community in 39 guava orchards in the semiarid region of the state of Sergipe, northeast Brazil. Field observations were made between July and October 2017, through a one-hour visit to each orchard. Samplings were conducted using the MacKinnon’s List method. In addition to bird sampling, walks were carried out in the orchards to observe nesting. Seventy-six species of birds belonging to 30 families were recorded using the guava orchards. The most frequent species were Vanellus chilensis, Columbina talpacoti, Columbina picui, Crotophaga ani, Pitangus sulphuratus and Sporophila albogularis. Of the 186 nests recorded in the orchards, the majority (n = 144 nests; 77.4%) belonged to Columbina picui, Columbina talpacoti and Columbina minuta. The results demonstrate that the bird community in the guava orchards is formed only by disturb-tolerant species, showing that the studied guava orchards are not favorable to the conservation of disturb-sensitive birds of the Caatinga domain.

The Responses of Light Reaction of Photosynthesis to Dynamic Sunflecks in a Typically Shade-Tolerant Species Panax notoginseng

Light is highly heterogeneous in natural conditions, and plants need to evolve a series of strategies to acclimate the dynamic light since it is immobile. The present study aimed to elucidate the response of light reaction of photosynthesis to dynamic sunflecks in a shade-tolerant species Panax notoginseng and to examine the regulatory mechanisms involved in an adaptation to the simulated sunflecks. When P. notoginseng was exposed to the simulated sunflecks, non-photochemical quenching (NPQ) increased rapidly to the maximum value. Moreover, in response to the simulated sunflecks, there was a rapid increase in light-dependent heat dissipation quantum efficiency of photosystem II (PSII) (ΦNPQ), while the maximum quantum yield of PSII under light (Fv′/Fm′) declined. The relatively high fluorescence and constitutive heat dissipation quantum efficiency of PSII (Φf,d) in the plants exposed to transient high light (400, 800, and 1,600 μmol m–2 s–1) was accompanied by the low effective photochemical quantum yield of PSII (ΦPSII) after the dark recovery for 15 min, whereas the plants exposed to transient low light (50 μmol m–2 s–1) has been shown to lead to significant elevation in ΦPSII after darkness recovery. Furthermore, PSII fluorescence and constitutive heat dissipation electron transfer rate (Jf,d) was increased with the intensity of the simulated sunflecks, the residual absorbed energy used for the non-net carboxylative processes (JNC) was decreased when the response of electron transfer rate of NPQ pathway of PSII (JNPQ) to transient low light is restricted. In addition, the acceptor-side limitation of PSI [Y(NA)] was increased, while the donor-side limitation of photosystems I (PSI) [Y(ND)] was decreased at transient high light conditions accompanied with active cyclic electron flow (CEF). Meanwhile, when the leaves were exposed to transient high light, the xanthophyll cycle (V cycle) was activated and subsequently, the JNPQ began to increase. The de-epoxidation state [(Z + A)/(V + A + Z)] was strongly correlated with NPQ in response to the sunflecks. In the present study, a rapid engagement of lutein epoxide (Lx) after the low intensity of sunfleck together with the lower NPQ contributed to an elevation in the maximum photochemical quantum efficiency of PSII under the light. The analysis based on the correlation between the CEF and electron flow devoted to Ribulose-1, 5-bisphosphate (RuBP) oxygenation (JO) indicated that at a high light intensity of sunflecks, the electron flow largely devoted to RuBP oxygenation would contribute to the operation of the CEF. Overall, photorespiration plays an important role in regulating the CEF of the shade-tolerant species, such as P. notoginseng in response to transient high light, whereas active Lx cycle together with the decelerated NPQ may be an effective mechanism of elevating the maximum photochemical quantum efficiency of PSII under light exposure to transient low light.

Differences in leaf litter usage as food sources, refuge, and foraging substrates by invertebrates in forest and grasslands in the eastern Amazon

Forest conversion into grassland changes the environment, microhabitat, and food availability. Leaf litter microhabitats change from complex leaf variety piles to nutrient-poor grass heaps. In this context, this work aimed to investigate how the invertebrate compositions in the forest and grassland leaf litters differ in litter usage. To achieve this goal, litterbag traps were placed in four secondary forest samples and four grassland samples from the eastern Amazon. After litter exposure, the species were morphotyped and classified according to leaf litter usage as food, refuge, or foraging substrates. Disturbancesensible groups characterized the secondary forest, while disturbance-tolerant species characterized the grasslands. The proportion of individuals using litter as food in grasslands is almost twice that in the secondary forest, while the percentage of individuals using leaf litter as refuge is eighteen times higher in the forest than in the grasslands. It seems that predators forage in the leaf litter of the forest just as much as in grasslands. The greater proportion of invertebrates using litter as a refuge in the forest relates to the limiting space in the habitat. In turn, food availability is scarce in grasslands, so there is urgency in using litter as a food source in this case.

Modeling the forest dynamics of the Sierra Nevada under climate change using SORTIE-ND

Key message Model simulation results suggest that forests in the Sierra Nevada mountains of California will tend to increase in density and basal area in the absence of fire over the next century, and that climate change will favor increases in drought-tolerant species. Context Climate change is projected to intensify the natural summer drought period for Mediterranean-climate forests. Such changes may increase tree mortality, change species interactions and composition, and impact ecosystem services. Aims To parameterize SORTIE-ND, an individual-based, spatially explicit forest model, for forests in the Sierra Nevada, and to model forest responses to climate change. Methods We use 3 downscaled GCM projections (RCP 8.5) to project forest dynamics for 7 sites at different elevations. Results Basal area and stem density tended to increase in the absence of fire. Climate change effects differed by species, with more drought-tolerant species such as Jeffrey pine (Pinus jeffreyi A.Murray bis) and black oak (Quercus kelloggii Newb.) exhibiting increases in basal area and/or density. Conclusion Increasing forest density may favor carbon sequestration but could increase the risk of high-severity fires. Future analyses should include improved parameterization of reproduction and interactions of disturbance with climate effects.

The cold-drought tolerance trade-off in temperate woody plants constrains range size, but not range filling

Interspecific differences in plant species' ranges are shaped by complex mechanistic interactions, which have so far remained largely beyond the reach of comprehensive models and explanations. Previous attempts to find underlying mechanisms by examining physiological tolerances to cold and heat separately have yielded contradictory results. Here we test the hypothesis that, instead of examining single stressors, abiotic stress tolerance syndromes that involve trade-offs between multiple abiotic stressors (namely drought, cold, waterlogging and shade), will provide reliable explanations. We compiled a dataset of actual range size and range filling (the ratio between actual and potential species range) as range metrics for 331 temperate woody plants species from Europe and North America. Tolerance syndromes were expressed as two PCA axes. One axis reflects a drought-cold/waterlogging tolerance trade-off (cold/wet-drought trade-off), the second axis represents a shade tolerance spectrum. Phylogenetic generalized linear mixed models were used to model the range metric vs. tolerance axes relationships using latitude as an additional main effect, and phylogeny and plant functional type as random effects. Actual range scaled negatively with the cold/wet-drought tolerance trade-off axis, mostly independently of latitude and continent. Thus, cold/wet-tolerant species had the largest ranges and drought tolerant species the smallest. The negative sign of the relationship was independent of phylogeny and plant functional type. In contrast, range filling depended on latitude. However, deciduous and evergreen species displayed different distributions of range metrics and tolerance syndromes. No significant relationships with the shade tolerance spectrum were found. Our findings demonstrate that the cold/wet-drought trade-off partly explains interspecific range size differences. However, this trade-off did not explain range filling. We also showed that fundamental adaptations of species also significantly influence range sizes, stress avoidance through the deciduous habit also explained interspecific differences in range size

ASSESSING ANT DIVERSITY IN AGROECOSYSTEMS: THE CASE OFITALIAN VINEYARDS OF THE ADIGE VALLEY

Agroecosystems have gained a dominant positionon worldwide land-usage, and therefore preserving their biodiversity is crucial for environmental sustainability. Ants are one of the most widespread groups of terrestrial arthropods, and,thanks to their significant diversification,they are considered as a good proxy group for bio-diversity monitoring, also in agroecosystems. Vineyards are economically valuable cultures widespread worldwide,and hosting many ant species, that provide meaningful ecosystem services and disservices. Despite the important role that ants play in these agroecosystems, ant biodiversity in vineyards is still poorly studied, especially in Italy. In this context, we present a first detailed quantitative and qualitative assessment of the ant fauna of Italian vineyards from the Adige Valley based on pitfall traps data, and discuss the results in comparison with the few other similar assessments from Europe and other continents. We document anassemblage of 22 species (7-16 per or-chard), mostly dominated by three disturbance-tolerant species (including an introduced species). Vineyards’ ant faunas appear to be rather heterogeneous worldwide, mainly following local ecological and biogeographical constraints, and the role that most ant species play in these agroecosystems is presently unknown.

Pollution Resistance Assessment of Plants Around Chromite Mine Based on Anticipated Performance Index, Dust Capturing Capacity and Metal Accumulation Index

Plant species sustaining under a polluted environment for long time are considered as potentially resistant species. Those plant species can be considered as an eco-sustainable tool used to bio-monitor and mitigate pollution. This study was carried out on total ten commonly available plant species to assess their anticipated performance index (API), Dust capturing capacity (DCC) and Metal accumulation index (MAI) in chromite mine and control area. According to Anticipated performance index (API) Macranga peltata, Holarrhena pubescens and Ficus hispida are highly tolerant species while Terminalia arjuna and Trema orientalis are intermediate tolerant species. Ficus hispida was also showed the highest dust capturing capacity (5.94 ± 0.43 mg/cm2) and whereas Woodfordia fruticosa (1.03 ± 0.11 mg/cm2) was found to be lowest. Metal accumulation index ranged from 17.29 to 4.5 and 6.38 to 1.94 at mine and control area respectively. Two-way ANOVA analysis revealed area wise significant differences between biochemical and physiological parameters. Also, result showed that the pollution level and heavy metal affected different biochemical and physiological parameter of plant species at mining area. The plant species with highest API, DCC and MAI value could be recommended for greenbelt development in different polluted area.