TY - GEN A1 - Pearce, Warren A1 - Özkula, Suay M. A1 - Greene, Amanda K. A1 - Teeling, Lauren A1 - Bansard, Jennifer S. A1 - Omena, Janna Joceli A1 - Rabello, Elaine Teixeira T1 - Visual cross-platform analysis BT - Digital methods to research social media images T2 - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe N2 - Analysis of social media using digital methods is a flourishing approach. However, the relatively easy availability of data collected via platform application programming interfaces has arguably led to the predominance of single-platform research of social media. Such research has also privileged the role of text in social media analysis, as a form of data that is more readily gathered and searchable than images. In this paper, we challenge both of these prevailing forms of social media research by outlining a methodology for visual cross-platform analysis (VCPA), defined as the study of still and moving images across two or more social media platforms. Our argument contains three steps. First, we argue that cross-platform analysis addresses a gap in research methods in that it acknowledges the interplay between a social phenomenon under investigation and the medium within which it is being researched, thus illuminating the different affordances and cultures of web platforms. Second, we build on the literature on multimodal communication and platform vernacular to provide a rationale for incorporating the visual into cross-platform analysis. Third, we reflect on an experimental cross-platform analysis of images within social media posts (n = 471,033) used to communicate climate change to advance different modes of macro- and meso-levels of analysis that are natively visual: image-text networks, image plots and composite images. We conclude by assessing the research pathways opened up by VCPA, delineating potential contributions to empirical research and theory and the potential impact on practitioners of social media communication. T3 - Zweitveröffentlichungen der Universität Potsdam : Wirtschafts- und Sozialwissenschaftliche Reihe - 199 KW - research methodology KW - visual analysis KW - social media KW - climate change Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-515539 SN - 1867-5808 IS - 2 ER - TY - JOUR A1 - Pearce, Warren A1 - Özkula, Suay M. A1 - Greene, Amanda K. A1 - Teeling, Lauren A1 - Bansard, Jennifer S. A1 - Omena, Janna Joceli A1 - Rabello, Elaine Teixeira T1 - Visual cross-platform analysis JF - Information, Communication and Society: digital methods to research social media images N2 - Analysis of social media using digital methods is a flourishing approach. However, the relatively easy availability of data collected via platform application programming interfaces has arguably led to the predominance of single-platform research of social media. Such research has also privileged the role of text in social media analysis, as a form of data that is more readily gathered and searchable than images. In this paper, we challenge both of these prevailing forms of social media research by outlining a methodology for visual cross-platform analysis (VCPA), defined as the study of still and moving images across two or more social media platforms. Our argument contains three steps. First, we argue that cross-platform analysis addresses a gap in research methods in that it acknowledges the interplay between a social phenomenon under investigation and the medium within which it is being researched, thus illuminating the different affordances and cultures of web platforms. Second, we build on the literature on multimodal communication and platform vernacular to provide a rationale for incorporating the visual into cross-platform analysis. Third, we reflect on an experimental cross-platform analysis of images within social media posts (n = 471,033) used to communicate climate change to advance different modes of macro- and meso-levels of analysis that are natively visual: image-text networks, image plots and composite images. We conclude by assessing the research pathways opened up by VCPA, delineating potential contributions to empirical research and theory and the potential impact on practitioners of social media communication. KW - research methodology KW - visual analysis KW - social media KW - climate change Y1 - 2018 U6 - https://doi.org/10.1080/1369118X.2018.1486871 SN - 1468-4462 SN - 1369-118X VL - 23 IS - 2 SP - 161 EP - 180 PB - Routledge CY - London ER - TY - JOUR A1 - Perring, Michael P. A1 - Bernhardt-Roemermann, Markus A1 - Baeten, Lander A1 - Midolo, Gabriele A1 - Blondeel, Haben A1 - Depauw, Leen A1 - Landuyt, Dries A1 - Maes, Sybryn L. A1 - De Lombaerde, Emiel A1 - Caron, Maria Mercedes A1 - Vellend, Mark A1 - Brunet, Joerg A1 - Chudomelova, Marketa A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Dirnboeck, Thomas A1 - Doerfler, Inken A1 - Durak, Tomasz A1 - De Frenne, Pieter A1 - Gilliam, Frank S. A1 - Hedl, Radim A1 - Heinken, Thilo A1 - Hommel, Patrick A1 - Jaroszewicz, Bogdan A1 - Kirby, Keith J. A1 - Kopecky, Martin A1 - Lenoir, Jonathan A1 - Li, Daijiang A1 - Malis, Frantisek A1 - Mitchell, Fraser J. G. A1 - Naaf, Tobias A1 - Newman, Miles A1 - Petrik, Petr A1 - Reczynska, Kamila A1 - Schmidt, Wolfgang A1 - Standovar, Tibor A1 - Swierkosz, Krzysztof A1 - Van Calster, Hans A1 - Vild, Ondrej A1 - Wagner, Eva Rosa A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Global environmental change effects on plant community composition trajectories depend upon management legacies JF - Global change biology N2 - The contemporary state of functional traits and species richness in plant communities depends on legacy effects of past disturbances. Whether temporal responses of community properties to current environmental changes are altered by such legacies is, however, unknown. We expect global environmental changes to interact with land-use legacies given different community trajectories initiated by prior management, and subsequent responses to altered resources and conditions. We tested this expectation for species richness and functional traits using 1814 survey-resurvey plot pairs of understorey communities from 40 European temperate forest datasets, syntheses of management transitions since the year 1800, and a trait database. We also examined how plant community indicators of resources and conditions changed in response to management legacies and environmental change. Community trajectories were clearly influenced by interactions between management legacies from over 200 years ago and environmental change. Importantly, higher rates of nitrogen deposition led to increased species richness and plant height in forests managed less intensively in 1800 (i.e., high forests), and to decreases in forests with a more intensive historical management in 1800 (i.e., coppiced forests). There was evidence that these declines in community variables in formerly coppiced forests were ameliorated by increased rates of temperature change between surveys. Responses were generally apparent regardless of sites’ contemporary management classifications, although sometimes the management transition itself, rather than historic or contemporary management types, better explained understorey responses. Main effects of environmental change were rare, although higher rates of precipitation change increased plant height, accompanied by increases in fertility indicator values. Analysis of indicator values suggested the importance of directly characterising resources and conditions to better understand legacy and environmental change effects. Accounting for legacies of past disturbance can reconcile contradictory literature results and appears crucial to anticipating future responses to global environmental change. KW - biodiversity change KW - climate change KW - disturbance regime KW - forestREplot KW - herbaceous layer KW - management intensity KW - nitrogen deposition KW - plant functional traits KW - time lag KW - vegetation resurvey Y1 - 2017 U6 - https://doi.org/10.1111/gcb.14030 SN - 1354-1013 SN - 1365-2486 VL - 24 IS - 4 SP - 1722 EP - 1740 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Huang, Xiaozhong A1 - Peng, Wei A1 - Rudaya, Natalia A1 - Grimm, Eric C. A1 - Chen, Xuemei A1 - Cao, Xianyong A1 - Zhang, Jun A1 - Pan, Xiaoduo A1 - Liu, Sisi A1 - Chen, Chunzhu A1 - Chen, Fahu T1 - Holocene vegetation and climate dynamics in the Altai Mountains and Surrounding Areas JF - Geophysical research letters N2 - A comprehensive understanding of the regional vegetation responses to long-term climate change will help to forecast Earth system dynamics. Based on a new well-dated pollen data set from Kanas Lake and a review on the published pollen records in and around the Altai Mountains, the regional vegetation dynamics and forcing mechanisms are discussed. In the Altai Mountains, the forest optimum occurred during 10-7ka for the upper forest zone and the tree line decline and/or ecological shifts were caused by climatic cooling from around 7ka. In the lower forest zone, the forest reached an optimum in the middle Holocene, and then increased openness of the forest, possibly caused by both climate cooling and human activities, took place in the late Holocene. In the lower basins or plains around the Altai Mountains, the development of protograssland or forest benefited from increasing humidity in the middle to late Holocene. Plain Language Summary In the Altai Mountains and surrounding area of central Asia, the previous studies of the Holocene paleovegetation and paleoclimate studies did not discuss the different ecological limiting factors for the vegetation in high mountains and low-elevation areas due to limited data. With accumulating fossil pollen data and surface pollen data, it is possible to understand better the geomorphological effect on the vegetation and discrepancies of vegetation/forest responses to large-scale climate forcing, and it is also possible to get reliable quantitative reconstructions of climate. Here our new pollen data and review on the published fossil pollen data will help us to look into the past climate change and vertical evolution of vegetation in this important area of the Northern Hemisphere. Based on our study, it can be concluded that the growth of taiga forest in the wetter areas may be promoted under a future warmer climate, while the forest in the relatively dry areas is liable to decline, and the different vegetation dynamics will contribute to future high-resolution coupled vegetation-climate model for Earth system modelling. KW - climate change KW - Kanas Lake KW - Altai Mountains KW - vegetation dynamics KW - taiga forest Y1 - 2018 U6 - https://doi.org/10.1029/2018GL078028 SN - 0094-8276 SN - 1944-8007 VL - 45 IS - 13 SP - 6628 EP - 6636 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Grimm-Seyfarth, Annegret A1 - Mihoub, Jean-Baptiste A1 - Gruber, Bernd A1 - Henle, Klaus T1 - Some like it hot BT - from individual to population responses of an arboreal arid-zone gecko to local and distant climate JF - Ecological monographs N2 - Accumulating evidence has demonstrated considerable impact of climate change on biodiversity, with terrestrial ectotherms being particularly vulnerable. While climate-induced range shifts are often addressed in the literature, little is known about the underlying ecological responses at individual and population levels. Using a 30-yr monitoring study of the long-living nocturnal gecko Gehyra variegata in arid Australia, we determined the relative contribution of climatic factors acting locally (temperature, rainfall) or distantly (La Nina induced flooding) on ecological processes ranging from traits at the individual level (body condition, body growth) to the demography at population level (survival, sexual maturity, population sizes). We also investigated whether thermoregulatory activity during both active (night) and resting (daytime) periods of the day can explain these responses. Gehyra variegata responded to local and distant climatic effects. Both high temperatures and high water availability enhanced individual and demographic parameters. Moreover, the impact of water availability was scale independent as local rainfall and La Nina induced flooding compensated each other. When water availability was low, however, extremely high temperatures delayed body growth and sexual maturity while survival of individuals and population sizes remained stable. This suggests a trade-off with traits at the individual level that may potentially buffer the consequences of adverse climatic conditions at the population level. Moreover, hot temperatures did not impact nocturnal nor diurnal behavior. Instead, only cool temperatures induced diurnal thermoregulatory behavior with individuals moving to exposed hollow branches and even outside tree hollows for sun-basking during the day. Since diurnal behavioral thermoregulation likely induced costs on fitness, this could decrease performance at both individual and population level under cool temperatures. Our findings show that water availability rather than high temperature is the limiting factor in our focal population of G.variegata. In contrast to previous studies, we stress that drier rather than warmer conditions are expected to be detrimental for nocturnal desert reptiles. Identifying the actual limiting climatic factors at different scales and their functional interactions at different ecological levels is critical to be able to predict reliably future population dynamics and support conservation planning in arid ecosystems. KW - behavioral adaptation KW - body condition KW - body growth rate KW - climate change KW - El Nino Southern Oscillation (ENSO) KW - Gehyra variegata KW - population dynamics KW - population size KW - survival KW - thermoregulation Y1 - 2018 U6 - https://doi.org/10.1002/ecm.1301 SN - 0012-9615 SN - 1557-7015 VL - 88 IS - 3 SP - 336 EP - 352 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - van Kleunen, Mark A1 - Essl, Franz A1 - Pergl, Jan A1 - Brundu, Giuseppe A1 - Carboni, Marta A1 - Dullinger, Stefan A1 - Early, Regan A1 - Gonzalez-Moreno, Pablo A1 - Groom, Quentin J. M. A1 - Hulme, Philip E. A1 - Kueffer, Christoph A1 - Kühn, Ingolf A1 - Maguas, Cristina A1 - Maurel, Noelie A1 - Novoa, Ana A1 - Parepa, Madalin A1 - Pysek, Petr A1 - Seebens, Hanno A1 - Tanner, Rob A1 - Touza, Julia A1 - Verbrugge, Laura A1 - Weber, Ewald A1 - Dawson, Wayne A1 - Kreft, Holger A1 - Weigelt, Patrick A1 - Winter, Marten A1 - Klonner, Guenther A1 - Talluto, Matthew V. A1 - Dehnen-Schmutz, Katharina T1 - The changing role of ornamental horticulture in alien plant invasions JF - Biological reviews N2 - The number of alien plants escaping from cultivation into native ecosystems is increasing steadily. We provide an overview of the historical, contemporary and potential future roles of ornamental horticulture in plant invasions. We show that currently at least 75% and 93% of the global naturalised alien flora is grown in domestic and botanical gardens, respectively. Species grown in gardens also have a larger naturalised range than those that are not. After the Middle Ages, particularly in the 18th and 19th centuries, a global trade network in plants emerged. Since then, cultivated alien species also started to appear in the wild more frequently than non-cultivated aliens globally, particularly during the 19th century. Horticulture still plays a prominent role in current plant introduction, and the monetary value of live-plant imports in different parts of the world is steadily increasing. Historically, botanical gardens - an important component of horticulture - played a major role in displaying, cultivating and distributing new plant discoveries. While the role of botanical gardens in the horticultural supply chain has declined, they are still a significant link, with one-third of institutions involved in retail-plant sales and horticultural research. However, botanical gardens have also become more dependent on commercial nurseries as plant sources, particularly in North America. Plants selected for ornamental purposes are not a random selection of the global flora, and some of the plant characteristics promoted through horticulture, such as fast growth, also promote invasion. Efforts to breed non-invasive plant cultivars are still rare. Socio-economical, technological, and environmental changes will lead to novel patterns of plant introductions and invasion opportunities for the species that are already cultivated. We describe the role that horticulture could play in mediating these changes. We identify current research challenges, and call for more research efforts on the past and current role of horticulture in plant invasions. This is required to develop science-based regulatory frameworks to prevent further plant invasions. KW - botanical gardens KW - climate change KW - horticulture KW - naturalised plants KW - ornamental plants KW - pathways KW - plant invasions KW - plant nurseries KW - trade KW - weeds Y1 - 2018 U6 - https://doi.org/10.1111/brv.12402 SN - 1464-7931 SN - 1469-185X VL - 93 IS - 3 SP - 1421 EP - 1437 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Steffen, Will A1 - Röckstrom, Johan A1 - Richardson, Katherine A1 - Lenton, Timothy M. A1 - Folke, Carl A1 - Liverman, Diana A1 - Summerhayes, Colin P. A1 - Barnosky, Anthony D. A1 - Cornell, Sarah E. A1 - Crucifix, Michel A1 - Donges, Jonathan Friedemann A1 - Fetzer, Ingo A1 - Lade, Steven J. A1 - Scheffer, Marten A1 - Winkelmann, Ricarda A1 - Schellnhuber, Hans Joachim T1 - Trajectories of the Earth System in the Anthropocene JF - Proceedings of the National Academy of Sciences of the United States of America N2 - We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a "Hothouse Earth" pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System-biosphere, climate, and societies-and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values. KW - Earth System trajectories KW - climate change KW - Anthropocene KW - biosphere feedbacks KW - tipping elements Y1 - 2018 U6 - https://doi.org/10.1073/pnas.1810141115 SN - 0027-8424 VL - 115 IS - 33 SP - 8252 EP - 8259 PB - National Acad. of Sciences CY - Washington ER - TY - JOUR A1 - Tape, Ken D. A1 - Jones, Benjamin M. A1 - Arp, Christopher D. A1 - Nitze, Ingmar A1 - Grosse, Guido T1 - Tundra be dammed BT - beaver colonization of the arctic JF - Global change biology N2 - Increasing air temperatures are changing the arctic tundra biome. Permafrost is thawing, snow duration is decreasing, shrub vegetation is proliferating, and boreal wildlife is encroaching. Here we present evidence of the recent range expansion of North American beaver (Castor canadensis) into the Arctic, and consider how this ecosystem engineer might reshape the landscape, biodiversity, and ecosystem processes. We developed a remote sensing approach that maps formation and disappearance of ponds associated with beaver activity. Since 1999, 56 new beaver pond complexes were identified, indicating that beavers are colonizing a predominantly tundra region (18,293km(2)) of northwest Alaska. It is unclear how improved tundra stream habitat, population rebound following overtrapping for furs, or other factors are contributing to beaver range expansion. We discuss rates and likely routes of tundra beaver colonization, as well as effects on permafrost, stream ice regimes, and freshwater and riparian habitat. Beaver ponds and associated hydrologic changes are thawing permafrost. Pond formation increases winter water temperatures in the pond and downstream, likely creating new and more varied aquatic habitat, but specific biological implications are unknown. Beavers create dynamic wetlands and are agents of disturbance that may enhance ecosystem responses to warming in the Arctic. KW - arctic tundra KW - beaver KW - climate change KW - permafrost KW - population recovery KW - salmon KW - shrub expansion KW - stream Y1 - 2018 U6 - https://doi.org/10.1111/gcb.14332 SN - 1354-1013 SN - 1365-2486 VL - 24 IS - 10 SP - 4478 EP - 4488 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Coch, Caroline A1 - Lamoureux, Scott F. A1 - Knoblauch, Christian A1 - Eischeid, Isabell A1 - Fritz, Michael A1 - Obu, Jaroslav A1 - Lantuit, Hugues T1 - Summer rainfall dissolved organic carbon, solute, and sediment fluxes in a small Arctic coastal catchment on Herschel Island (Yukon Territory, Canada) JF - Artic science N2 - Coastal ecosystems in the Arctic are affected by climate change. As summer rainfall frequency and intensity are projected to increase in the future, more organic matter, nutrients and sediment could bemobilized and transported into the coastal nearshore zones. However, knowledge of current processes and future changes is limited. We investigated streamflow dynamics and the impacts of summer rainfall on lateral fluxes in a small coastal catchment on Herschel Island in the western Canadian Arctic. For the summer monitoring periods of 2014-2016, mean dissolved organic matter flux over 17 days amounted to 82.7 +/- 30.7 kg km(-2) and mean total dissolved solids flux to 5252 +/- 1224 kg km(-2). Flux of suspended sediment was 7245 kg km(-2) in 2015, and 369 kg km(-2) in 2016. We found that 2.0% of suspended sediment was composed of particulate organic carbon. Data and hysteresis analysis suggest a limited supply of sediments; their interannual variability is most likely caused by short-lived localized disturbances. In contrast, our results imply that dissolved organic carbon is widely available throughout the catchment and exhibits positive linear relationship with runoff. We hypothesize that increased projected rainfall in the future will result in a similar increase of dissolved organic carbon fluxes. KW - permafrost KW - hydrology KW - lateral fluxes KW - hysteresis KW - climate change Y1 - 2018 U6 - https://doi.org/10.1139/as-2018-0010 SN - 2368-7460 VL - 4 IS - 4 SP - 750 EP - 780 PB - Canadian science publishing CY - Ottawa ER - TY - JOUR A1 - Maes, Sybryn L. A1 - Perring, Michael P. A1 - Vanhellemont, Margot A1 - Depauw, Leen A1 - Van den Bulcke, Jan A1 - Brumelis, Guntis A1 - Brunet, Jorg A1 - Decocq, Guillaume A1 - den Ouden, Jan A1 - Härdtle, Werner A1 - Hedl, Radim A1 - Heinken, Thilo A1 - Heinrichs, Steffi A1 - Jaroszewicz, Bogdan A1 - Kopecký, Martin A1 - Malis, Frantisek A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Environmental drivers interactively affect individual tree growth across temperate European forests JF - Global change biology N2 - Forecasting the growth of tree species to future environmental changes requires abetter understanding of its determinants. Tree growth is known to respond to global‐change drivers such as climate change or atmospheric deposition, as well as to localland‐use drivers such as forest management. Yet, large geographical scale studiesexamining interactive growth responses to multiple global‐change drivers are relativelyscarce and rarely consider management effects. Here, we assessed the interactiveeffects of three global‐change drivers (temperature, precipitation and nitrogen deposi-tion) on individual tree growth of three study species (Quercus robur/petraea, Fagus syl-vatica and Fraxinus excelsior). We sampled trees along spatial environmental gradientsacross Europe and accounted for the effects of management for Quercus. We collectedincrement cores from 267 trees distributed over 151 plots in 19 forest regions andcharacterized their neighbouring environment to take into account potentially confounding factors such as tree size, competition, soil conditions and elevation. Wedemonstrate that growth responds interactively to global‐change drivers, with species ‐specific sensitivities to the combined factors. Simultaneously high levels of precipita-tion and deposition benefited Fraxinus, but negatively affected Quercus’ growth, high-lighting species‐specific interactive tree growth responses to combined drivers. ForFagus, a stronger growth response to higher temperatures was found when precipita-tion was also higher, illustrating the potential negative effects of drought stress underwarming for this species. Furthermore, we show that past forest management canmodulate the effects of changing temperatures on Quercus’ growth; individuals in plotswith a coppicing history showed stronger growth responses to higher temperatures.Overall, our findings highlight how tree growth can be interactively determined by glo-bal‐change drivers, and how these growth responses might be modulated by past for-est management. By showing future growth changes for scenarios of environmentalchange, we stress the importance of considering multiple drivers, including past man-agement and their interactions, when predicting tree growth. KW - basal area increment KW - climate change KW - Fagus KW - Fraxinus KW - historical ecology KW - nitrogen deposition KW - Quercus KW - tree-ring analysis Y1 - 2018 U6 - https://doi.org/10.1111/gcb.14493 SN - 1354-1013 SN - 1365-2486 VL - 25 IS - 1 SP - 201 EP - 217 PB - Wiley CY - Hoboken ER -