Quantifying Biochemical Traits over the Patagonian Sub-Antarctic Forests and Their Relation to Multispectral Vegetation Indices

The effects and consequences of global warming on the productivity of the Patagonian forest are still unknown. The use of Unmanned Aerial Vehicles (UAV) promotes new knowledge of the most pristine and unknown sub-antarctic forests located in Chilean Patagonia. This work presents an initial approach to spatialize biochemicals over the Patagonian forests using ultra-high spatial resolution imagery acquired from UAVs equipped with a multispectral (visible, near-infrared, and thermal) sensor. The images were obtained in multiple flights over the Cerro Castillo National Park (Aysén Region, Chile), and several Vegetation Indices (VIs) were estimated. Leaves of Nothofagus pumilio (Poepp. et Endl.) Krasser (Nothofagaceae) individuals were extracted after the flights and were then used to determine the biochemicals traits of chlorophylls (Chl-a and Chl-b) and carotenoids pigments, as well as the total phenolic content (TPC), total flavonoids content (TFC), and the DPPH radical scavenging assay. Their relationships with multiple VIs was analyzed in order to assess the spatiality of the biochemicals traits in the forest during it most productive phenological stage. Results showed high correlations for the biochemical traits pigments (R2 > 0.75) with the indices DVI, MCARI, and MSAVI1 as the best performing indices, while further spectral availability is needed for significant correlations with biochemicals traits related to the antioxidant capacity. Spatialization of the biochemical traits within UAV imagery was also performed evaluating their representation in the forest. This work allowed us to identify the different spectral behavior of the N. pumilio species, its relation to biochemical traits, and their spatialization, thus presenting the first step to developing a monitoring protocol for the evaluation of the Patagonian forests under the current global warming scenarios in the region.

Variability in fruit traits and anthocyanin content among and within populations of underutilized Patagonian species Berberis microphylla G. Forst.

BACKGROUND: The Berberis microphylla (calafate) is an evergreen shrub considered a non-timber product from the Patagonian forest, relevant for the diversification of agrifood production, particularly interesting since its black–blue fruits are extremely rich in phenolic compounds. OBJECTIVE: The main objectives were to: (1) quantify the variability of fruit traits, anthocyanin content, efficiency of the reproductive shoots and leaf nutrient content within the set of 34 B. microphylla wild accessions from Tierra del Fuego Island, Argentina, (2) calculate the coefficients of correlation between variables and (3) detect relationships between the genotypes. METHODS: Plants growing near Ushuaia city (n = 12), bordering Fagnano lake (n = 12) and central area of the Tierra del Fuego Island (n = 10) were selected. RESULTS: A significant variability in fruit traits, anthocyanin content and the efficiency of reproductive shoots among and within the three populations was assessed, a result with great relevance for breeding purposes. Phenotypic plasticity was related with the environmental conditions, i.e. air temperatures for each population during the three monitored growing seasons. CONCLUSIONS: Overall, results indicate that yearly environmental factors play a relevant role in phenotypic variation of both individual plants and populations, thus confirming the complexity of wild species evolution and domestication processes.

Oribatid mites (Acari: Oribatida) from the Patagonian steppe, Argentina

Knowledge of the oribatid mite community from Patagonian steppe is scarce compared with other environments, such as the Andean-Patagonian forest. In the present research we identified oribatid mites under different environmental conditions: two Patagonian steppe types (grass and shrub), two soil characteristics (bare and covered soil) and two different seasons (autumn and spring). A total of 42 species/morphospecies were found, 13 were new records for Chubut and one was a new record for Argentina. In view of its ecological role in soil formation, it is fundamental that knowledge about this fauna is enhanced in order to provide baselines for study and to aid further understanding about its ecology.

Obsidian Distribution of the Northern Patagonian Forest Area and Neighboring Sectors during the Late Holocene (Neuquén Province, Argentina)

Analysis of 519 obsidian artifacts (pebbles, debitage, cores and small bifaces) by nondestructive X-ray fluorescence from forests and steppes of southern Lanín National Park in the northern Patagonian Andean region, from Lácar (chemical group QU/AP), Lolog (CP-LL 1), Filo Hua-Hum (FHH), Paillakura (Pk, former unknown 1 group), Meliquina (MQ, former unknown group 2) and Yuco (YC) sources. Neutron activation analysis was applied to 29 of the artifacts. We identified for the first time the presence of obsidian from distant Covunco (PC1) in the center of Neuquén. This paper is the first English language publication of our ongoing, ten-year-long research. In accordance with previous work, but using other analytical techniques, the most frequently used sources during the late Holocene remain CP/LL 1 and Pk, here we add YC, mainly by the incorporation of new sites recently surveyed in the islands and the coast of Lake Lácar, next to its source. Another result consistent with previous work is the absence of obsidian from Mendoza and Chilean sources; therefore, we suggest these obsidians circulate just to the east and northeast, allowing us to discuss issues of human territoriality during the Late Holocene.

A new multi-proxy record of environmental change over the last 1000 years on Chiloé Island: Lake Pastahué, south-central Chile (42°S)

Knowledge of past environmental and climatic conditions of lake ecosystems on Chiloé Island on a millennial scale is limited. Hence, this study fills a gap in our understanding of this part of southern Chile. The aim of this study was to reconstruct the environmental and climatic history of the last 1000 years of Lake Pastahué through a multi-proxy sediment core analysis. The 1-m-long core was subsampled every centimeter for the organic matter, magnetic susceptibility, grain-size distribution, and biological indicator (pollen, chironomids) analyses. The age model was constructed from 210Pb, 137Cs, and 14C activity. Pollen results revealed a North Patagonian forest composition represented by Nothofagus, Weinmannia, Drimys, Tepualia, Myrtaceae, Poaceae, and Pteridophyta. The abundance of Rumex and Pinus in the most recent part of the pollen assemblage reflects a clear anthropogenic impact. The sedimentological parameters and chironomid assemblage show similar variations, which highlight changes in the trophic state of the lake. The changes observed in all proxies suggest the influence of climate events such as the ‘Medieval Climate Anomaly’ (MCA) and ‘Little Ice Age’ (LIA). The variations observed since the beginning of the 20th century could be the result of the combined effect of anthropogenic activities and the increase in temperature recorded in south-central Chile and Patagonia.