Search

We assessed the impact of road disturbances on the dominant mycorrhizal types in ecosystems at the global level and how this mechanism can potentially lead to lasting plant community changes. We used a database of coordinated plant community surveys following mountain roads from 894 plots in 11 mountain regions across the globe in combination with an existing database of mycorrhizal–plant associations in order to approximate the relative abundance of mycorrhizal types in natural and disturbed environments. Our findings show that roadside disturbance promotes the cover of plants associated with arbuscular mycorrhizal (AM) fungi. This effect is especially strong in colder mountain environments and in mountain regions where plant communities are dominated by ectomycorrhizal (EcM) or ericoid‐mycorrhizal (ErM) associations. Furthermore, non‐native plant species, which we confirmed to be mostly AM plants, are more successful in environments dominated by AM associations. These biogeographical patterns suggest that changes in mycorrhizal types could be a crucial factor in the worldwide impact of anthropogenic disturbances on mountain ecosystems. Indeed, roadsides foster AM‐dominated systems, where AM‐fungi might aid AM‐associated plant species while potentially reducing the biotic resistance against invasive non‐native species, often also associated with AM networks. Restoration efforts in mountain ecosystems will have to contend with changes in the fundamental make‐up of EcM‐ and ErM plant communities induced by roadside disturbance. [ABSTRACT FROM AUTHOR]

Copyright of Biological Invasions is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Andes mountain range in South America has a high level of endemism and is a major source of ecosystem services. The Andes is increasingly threatened by anthropogenic disturbances that have allowed the establishment of non-native plants, mainly in the lower elevation areas. However, synergies between climate change and anthropogenic pressure are promoting the spread of non-native plants to higher elevation areas. In this article, we evaluate and identify the main non-native plants invading Andean ecosystems, and assess their taxonomic families, growth forms and distribution patterns. Based on a systematic literature review, we identified the importance of climatic and anthropogenic factors as drivers of non-native species establishment in Andean ecosystems and the main impacts of non-native plants in the Andes. We then identified research gaps across each biogeographic region in the Andes. Finally, we highlight key elements to better tackle the problem of non-native plant invasions in Andean ecosystems, including the need for a systematic monitoring of invasion patterns and spread (e.g. MIREN protocol) and a common policy agenda across international borders for the prevention and management of non-native plants in this highly vulnerable region. [ABSTRACT FROM AUTHOR]

Pinus contorta is considered one of the most invasive tree species worldwide, generating significant impacts on biodiversity and ecosystems. In several Patagonian ecosystems in southern Chile, it has escaped from plantations established mainly in the 1970s, and is now invading both forests and treeless environments. In this study, we evaluated the impact of the invasion of P. contorta on microenvironmental conditions in Araucaria araucana forest and Patagonian steppe ecosystems, and assessed how these changes related to the richness and abundance of native and non-native plant species. In each ecosystem, 24 plots of 100 m2 were established along a gradient of P. contorta biomass, where 18 environmental variables and the composition of native and non-native vegetation were measured at a local scale. Our results indicated that increased pine biomass was associated with differences in microclimatic conditions (soil and air temperature, photosynthetically active radiation (PAR), and soil moisture) and soil properties (potassium, nitrate, pH, and litter accumulation). These changes were ecosystem dependent, however, as well as associated with the level of invasion. Finally, the reduction in the richness and abundance of native plants was associated with the changes in soil properties (accumulation of leaf litter, pH, and organic matter) as well as in the microclimate (minimum air temperature, PAR) generated by the invasion of P. contorta. Overall, our results confirm that the invasion of P. contorta impacts microenvironmental conditions (i.e., canopy cover, litter accumulation, minimum air temperature, and maximum soil temperature) and reduces native plant diversity. For future restoration plans, more emphasis should be given to how environmental changes can influence the recovery of invaded ecosystems even after the removal of the living pine biomass (i.e., legacy of the invasion). [ABSTRACT FROM AUTHOR]

The factors that determine patterns of non-native species richness and abundance are context dependent in both time and space. Global change has significantly boosted plant invasions in mountains, therefore, understanding which factors determine the invasion and at what scale they operate are fundamental for decision-making in the conservation of mountain ecosystems. Although much evidence has been gathered on the patterns of non-native species in mountain ecosystems, little is known about what specific abiotic, biotic, or anthropogenic factors are driven such patterns. Here, we assessed the importance of anthropogenic, biotic, and abiotic factors at two spatial scales as drivers of plant invasions along three roads in south-central Chile. We sampled non-native plant richness and abundance, and each of these explanatory factors, in-situ in 60 transects in disturbed areas and adjacent undisturbed vegetation. Low elevation areas were the most invaded, with patterns of richness and abundance driven mainly by anthropogenic factors, explaining between 20 and 50% of the variance for the three roads. Only for the abundance of non-native species along the road in the Malalcahuello National Reserve, biotic factors were more important (45% of the variance). At the regional scale, the abundance of non-native species was again explained best by anthropogenic factors (24% of the variance), yet non-native richness was driven most strongly by abiotic factors such as soil nitrogen content and pH (15% of the variance). Our results confirm the conclusions from experimental studies that anthropogenic factors override abiotic factors and are important drivers of non-native species at local and regional scales and that non-native plant invasion in mountains is currently not strongly limited by climate. [ABSTRACT FROM AUTHOR]

Current analyses and predictions of spatially explicit patterns and processes in ecology most often rely on climate data interpolated from standardized weather stations. This interpolated climate data represents long‐term average thermal conditions at coarse spatial resolutions only. Hence, many climate‐forcing factors that operate at fine spatiotemporal resolutions are overlooked. This is particularly important in relation to effects of observation height (e.g. vegetation, snow and soil characteristics) and in habitats varying in their exposure to radiation, moisture and wind (e.g. topography, radiative forcing or cold‐air pooling). Since organisms living close to the ground relate more strongly to these microclimatic conditions than to free‐air temperatures, microclimatic ground and near‐surface data are needed to provide realistic forecasts of the fate of such organisms under anthropogenic climate change, as well as of the functioning of the ecosystems they live in. To fill this critical gap, we highlight a call for temperature time series submissions to SoilTemp, a geospatial database initiative compiling soil and near‐surface temperature data from all over the world. Currently, this database contains time series from 7,538 temperature sensors from 51 countries across all key biomes. The database will pave the way toward an improved global understanding of microclimate and bridge the gap between the available climate data and the climate at fine spatiotemporal resolutions relevant to most organisms and ecosystem processes. [ABSTRACT FROM AUTHOR]

Seed germination depends on various biotic and abiotic interactions associated with maternal habitat. The formation of soil seed banks is a key strategy and has ecological implications, especially with regard to species that develop in extreme habitats. When establishing germplasm banks of these species from seeds, seed dormancy becomes one of the main difficulties. In this research, we study Colobanthus quitensis, a species with wide latitudinal and altitudinal distribution, inhabiting extreme environments from southern Mexico to maritime Antarctica. Furthermore, this species has been described to have a secondary dormancy that is dependent on the environment. In order to perform research without needing to have regular access to this species' habitats, it is therefore vital to possess plant material from different populations representing the species distribution. Thus, we evaluated the effects of various pre-germination treatments on germination percentage and time in four populations of the species. A differential and significant effect was evidenced, both among treatments and populations. Acid scarification increased germination percentage and decreased germination time. The best treatments were determined by population, and direct seeding after a brief period of cold stratification (4 °C) allowed us to achieve good germination percentages in at least three of the studied populations. This new evidence allows optimization in the introduction, development, characterization, and availability of plant material of the different C. quitensis populations in the Antarctic Vascular Plant Germplasm Bank. [ABSTRACT FROM AUTHOR]

Colobanthus quitensis (Antarctic pearlwort) is one of the only two native vascular plants to inhabit the extreme environmental conditions of Antarctica . Colobanthus quitensis has a wide geographic distribution, both in latitude and altitude, and always inhabits extreme environments. This makes it crucial for understanding environmental tolerance mechanisms, and a useful model for studies regarding genetic diversity and intraspecific morphology. Several morphological and molecular descriptors were applied to C. quitensis populations, constituting the first study of its kind in these species. We postulated that morphological variability is strongly linked to geographic distribution, and that this is manifested in external morphological characteristics and genetic structure. A large intra- and interpopulational morphological variability was verified. Both morphological variability and genetics made it possible to form two separate groups between continental and Antarctic island populations. The genetic diversity was high to moderate with the least amount of diversity towards the north. The genetic structure was high, and the gene flow between populations was low. The correlation between morphological, genetic, geographic and altitudinal distances permits the proposal of an isolation by distance model that can be used between populations with high Bio-geographical influence. Understanding what factors lead to local or colonization adaptation, and determining the morphological variations and genetic differentiation in populations of C. quitensis, is vital for the understanding of the evolutionary history that has contributed to the success of the establishment of this species in an environment as extreme as Antarctica. Additionally, this study demonstrates the usefulness of the combined use of morpho-physiological and molecular markers for variability and diversity studies. [ABSTRACT FROM AUTHOR]

The Antarctic terrestrial ecosystem is relatively simple and has low plant diversity. Taking into account the current effects of climate change and the exponential increase in visitors during the past 50 years, this ecosystem is very vulnerable to the arrival of non-native species. Fildes Peninsula, King George Island, is an area of high human impact due to the scientific and logistical activities that occur there making the area particularly interesting for the arrival of non-native species. In this study, we determine the spectrum of seeds arriving to the peninsula and being deposited in the topsoil. Soil samples were collected and analysed in order to identify and quantify plant material. The results indicate that there is a direct relationship between the sites where seeds were found and areas with higher levels of human activity on the peninsula. Eight species were identified, with the most common being Hypochaeris radicata and Senecio jacobaea. Seed quantification indicated that areas of high human activity are most vulnerable to the invasion and establishment of non-native species. This study is the first to demonstrate the presence of non-native seeds in the topsoil at Fildes Peninsula, Antarctica. [ABSTRACT FROM AUTHOR]

Copyright of Revista Chilena de Historia Natural is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A correction is presented to the article "Phenotypic variability and genetic differentiation in continental and island populations of Colobanthus quitensis (Caryophyllaceae: Antarctic pearlwort)" which published online in the September 1, 2017 issue.