Assessing distribution shifts and ecophysiological characteristics of the only Antarctic winged midge under climate change scenarios

Parts of Antarctica were amongst the most rapidly changing regions of the planet during the second half of the Twentieth Century. Even so, today, most of Antarctica remains in the grip of continental ice sheets, with only about 0.2% of its overall area being ice-free. The continent’s terrestrial fauna consists only of invertebrates, with just two native species of insects, the chironomid midges Parochlus steinenii and Belgica antarctica. We integrate ecophysiological information with the development of new high-resolution climatic layers for Antarctica, to better understand how the distribution of P. steinenii may respond to change over the next century under different IPCC climate change scenarios. We conclude that the species has the potential to expand its distribution to include parts of the west and east coasts of the Antarctic Peninsula and even coastal ice-free areas in parts of continental Antarctica. We propose P. steinenii as an effective native sentinel and indicator species of climate change in the Antarctic

A global assessment of the potential distribution of naturalized and planted populations of the ornamental alien tree Schinus molle

Estudio sobre la potencial invasión del pirul, una planta naturalizada cuyo origen es el sur de América.The Peruvian Peppertree (Schinus molle L.) is an evergreen tree native to semiarid environments of Peru and Bolivia in South America. This tree has been introduced and widely planted for ornamental and forestry purposes in several semiarid regions of the world because its seedlings are easily established and have a high survival rate; it also grows quickly, and it is tolerant of dry climates. We compared the global and regional niches of naturalized and planted populations of S. molle in order to examine the invasive stages and potential distribution of this species in four regions of the world. This work provides a novel approach for understanding the invasion dynamics of S. molle in these areas and elucidates the ecological processes that bring about such invasions. Most naturalized and planted populations were found to be in equilibrium with the environment. In its native range as well as in Australia and South Africa the models of the coverage area of habitat suitability for natural populations were the highest, whereas the coverage area of planted populations was lower. For planted populations in Australia and South Africa, a large percentage of predicted presences fell within sink populations. The invasion stages of S. molle vary across regions in its adventive range; this result may be attributable to residence time as well as climatic and anthropic factors that have contributed to the spread of populations.SEMARNAT-CONACYT [Grant FSSEMARNAT01-C-2018-1-A3-S-80837]

Using global and regional Species Distribution Models (SDM) to infer the invasive stage of latrodectus geometricus (Araneae: Theridiidae) in the Americas

© The Authors 2016. The brown widow spider, Latrodectus geometricus C. L. Koch, 1841, is a large spider of the family Theridiidae that belongs to a genus of medical interest owing to its potent neurotoxic venom, which causes severe pain in humans. In America, this alien spider has been found in virtually all countries in the region, mainly associated with human dwellings, but also in agricultural sectors. However, the invasive process and potential distribution of this invasive species across the American continent are completely unknown. In this context, using a combination of both global and regional niche models, it is possible to hypothesize the invasive phase of the species as well as the geographic space where these different phases occur. By comparing the global and regional niches of L. geometricus, we examined its invasive process and potential distribution across the American continent. This work is an innovative approach to understanding the invasion of the brown widow spid

Climatic niche conservatism and biogeographical non-equilibrium in Eschscholzia californica (Papaveraceae), an invasive plant in the Chilean Mediterranean region.

Species climate requirements are useful for predicting their geographic distribution. It is often assumed that the niche requirements for invasive plants are conserved during invasion, especially when the invaded regions share similar climate conditions. California and central Chile have a remarkable degree of convergence in their vegetation structure, and a similar Mediterranean climate. Such similarities make these geographic areas an interesting natural experiment for testing climatic niche dynamics and the equilibrium of invasive species in a new environment. We tested to see if the climatic niche of Eschscholzia californica is conserved in the invaded range (central Chile), and we assessed whether the invasion process has reached a biogeographical equilibrium, i.e., occupy all the suitable geographic locations that have suitable conditions under native niche requirements. We compared the climatic niche in the native and invaded ranges as well as the projected potential geographic distribution in the invaded range. In order to compare climatic niches, we conducted a Principal Component Analysis (PCA) and Species Distribution Models (SDMs), to estimate E. californica's potential geographic distribution. We also used SDMs to predict altitudinal distribution limits in central Chile. Our results indicated that the climatic niche occupied by E. californica in the invaded range is firmly conserved, occupying a subset of the native climatic niche but leaving a substantial fraction of it unfilled. Comparisons of projected SDMs for central Chile indicate a similarity, yet the projection from native range predicted a larger geographic distribution in central Chile compared to the prediction of the model constructed for central Chile. The projected niche occupancy profile from California predicted a higher mean elevation than that projected from central Chile. We concluded that the invasion process of E. californica in central Chile is consistent with climatic niche conservatism but there is potential for further expansion in Chile

Pérdida y fragmentación del bosque nativo en la cuenca del río Aysén (Patagonia-Chile) durante el siglo XX

This work estimates the loss and fragmentation of native forest in the watershed of the river Aysén during the 20th century, as a result of clearance fires induced by land settlers. In order to generate the reconstruction of the native forest cover, several documentary records and GIS ArcView 3.2 were used. Different indexes of landscape changes were applied (area, density and size of the fragment, core area, euclidean distance, shape and aggregation index, and edge length) to estimate the distribution of the native forest between 1900 and 1998, which indicate that the main replacement of the forest was by prairies. A loss of approximately 23% of native forest was registered, also an increase in the number of forest fragments (<100 ha), as a result of the settlement process. Howerer, the increasing number of fragments has a high connectivity, wich was corroborated using different landscape indexes.En este trabajo se estimó la pérdida y fragmentación de bosque nativo en la cuenca del río Aysén, ocurrida entre los años 1900 y 1998, debido principalmente a incendios forestales producto de la colonización del territorio. En la reconstrucción de la cobertura boscosa fueron de gran utilidad distintos registros históricos y el sistema de información geográfica (SIG ArcView 3.2). Se aplicaron diferentes índices del paisaje (área, densidad y tamaño del fragmento, área núcleo total, distancia euclidiana, índices de forma y de agregación, y longitud de borde total), evaluándose los cambios en los patrones de distribución del bosque nativo entre 1900 y 1998. Se reconoció que el bosque perdido fue reemplazado mayormente por praderas, evidenciándose una pérdida aproximada del 23%, de bosque nativo, identificándose además un aumento de fragmentos menores a 100 ha, y la disección de estos debido a los incendios generados durante la colonización. Sin embargo, dichos fragmentos presentarían una alta conectividad, situación que fue corroborada a través de diferentes índices de paisaje

Niche conservatism in a plant with long invasion history: the case of the Peruvian peppertree (Schinus molle, Anacardiaceae) in Mexico

Background and aim - Invasive plants should only colonize habitats meeting the environmental conditions included in their native niches. However, if they invade habitats with novel environmental conditions, this can induce shifts in their niches. This may occur in plants with long invasion histories because they interacted with the environmental conditions of invaded regions over long periods of time. We focused on this issue and evaluated whether the niche of the oldest plant invader reported in Mexico, the Peruvian peppertree, is still conserved after almost 500 years of invasion history. Methods - We compared climatic niches of the species between the native and invaded region. We later used species distribution models (SDM) to visualize the geographical expression of both niches in Mexico. Results - The invasive niche of the Peruvian peppertree is fully nested within the native niche. Although this suggests that the niche is conserved, this also indicates that a large fraction of the native niche is empty in the invaded region. The SDM from the native region indicated that Mexico contains habitats meeting the conditions included in this empty fraction of the native niche and, thus, this invasion should continue expanding. Nevertheless, the SDM calibrated with data from the invaded region indicated that peppertrees have colonized all suitable habitats indicated by its invasive niche and, thus, their populations should no longer expand. Conclusion - Our results suggests that the niche of the Peruvian peppertree is partially conserved in Mexico. This may have occurred because individuals introduced into Mexico constituted a small, nonrepresentative sample of the full niche of the species.ICM-02-005. PBF-23. CONACyT-169631. CONACyT-290749

Principal Component Analysis (PCA).

<p>The climatic niche of <i>Eschscholzia californica</i> in the native range in California (green) and in the invaded range in central Chile (red). The blue area corresponds to niche areas shared in both ranges (niche stability).The solid and dashed lines show 100% and 75% of the climatic envelope from the native (green) and from the invaded range (red), respectively. The green area is the unfilled climatic niche space in the invaded range, and the red area, is the expanded climatic niche in the invaded range. The more intense blue cells represent zones with higher occurrence densities in the invaded niche (central Chile). In the PCA analysis the first axis accounts for 47.66% of the total variance and mainly represents mean annual precipitation, precipitation during the warmest quarter and altitude; the second PCA axis accounts for 29.68% of the total variance and mainly represents precipitation seasonality. In the correlation circle, the hidden label (behind bio7) corresponds to temperature seasonality (bio4).</p

Species distribution models (SDMs) for <i>Eschscholzia californica</i> in central Chile.

<p>A) Generated with occurrences recorded in the invaded range (central Chile). B) Generated with occurrences recorded in the native range (California). C) Overlap of both SDMs. It shows that 99.9% of the invaded range predicted from central Chile (blue) is included in the area predicted from California; 65% of the area predicted from California (green) is not predicted by the SDM from central Chile; only a small proportion of area (0.1%) in Chile (red) is not predicted from California. AUC values for these models are displayed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0105025#pone-0105025-t001" target="_blank">Table 1</a>.</p

Uribe-Rivera et al 2017 DataSet: High resolution bioclimatic layers for southwest of South America for three recent past periods (1970, 1990 and 2010)

<p>These files were generated as part of the article "Dispersal and extrapolation on the accuracy of temporal predictions from distribution models for the Darwin’s frog" (Uribe-Rivera et al. 2017; accepted in Ecological Applications)</p> <p>We used point data of meteorological stations between 34°-48°S and 70°-75°W, to generate new climatic surfaces for three recent past periods (1970; 1990; 2010). Meteorological data encompassed 293 weather stations, and were extracted from three databases: Dirección Meteorológica de Chile (DMC); Dirección General de Aguas de Chile (DGA); and the FAOClim-NET Agroclimatic database management system (FAO 2001), recording monthly records of mean daily minimum temperature, mean daily maximum temperature and total rainfall for 5-year periods (1965-1969 for 1970 climatic conditions; 1985-1989 for 1990 climatic conditions; and 2005-2009 for 2010 climatic conditions). For each period monthly mean values of each climatic variable were interpolated to generate surfaces using Anusplin v.4.4 (Hutchinson and Xu 2006), which applies the same algorithm used to derive the WorldClim bioclimatic surfaces (Hijmans et al. 2005). Interpolations were fitted following Pliscoff et al. (2014) at a ~1x1 Km resolution, with elevation as an independent variable using the GTOPO30 global digital elevation model (USGS, 1996). Because some weather stations do not have information for every month, we used the option of non-data of Anusplin. The quality of interpolations of climatic data was assessed calculating the Pearson correlation coefficient at the cell level between the monthly climatic values from the CRU-TS v3.10.01 Historic Climate Database for GIS (Climatic Research Unit - Time Series, 2012), and the monthly climatic values from the new climatic layers. Finally, surfaces of 19 bioclimatic variables were generated using the dismo package in R (Hijmans et al. 2014).</p> <p>All bioclimatic layers were uploaded in a single compressed ZIP file. Individual layers can be found inside it as georeferenced ASCII raster files, and nominated primarily by time period, and secundarily by the number of bioclimatic layer, following the worldclim nomenclature (http://www.worldclim.org/bioclim).</p