Crop production structure and stability under climate change in South America

Southern South America is expected to play an increasingly important role in global food production, but climate change could seriously threaten it. Here we have analysed long‐term historical data for major crops (rice, oats, barley, sunflower, soybean, sorghum, wheat, maize) at subnational scale to (a) look for common features among crop yield dynamics, evaluating their structure and implications for the persistence of that crop; (b) address complex crop responses to changes in environmental growing conditions; and (c) identify climate impact hotspots that are crucial for adaptation and mitigation. We have proposed a novel methodological approach based on dynamics systems in order to understand the processes behind annual crop yield fluctuations. We report the results of general patterns in the internal process (biophysical adjustments by rapid negative feedbacks) regulating crop production and analyse how it influences crop persistence and yield ceilings. The structure of a crop yield dynamic system defines its behaviour, but climate variations could displace it from yield equilibrium and affect its stability. Our findings suggest that weather conditions have a stronger impact on yield growth at high rather than at low yield levels (non‐additive impacts). This allows agriculture management to be refined and applied more efficiently, weakening the relationship between crop productivity and climate change and predicting the response of crop production to yield‐improvement strategies. We have identified those crops and regions which are most vulnerable to the current climate change trends in southern South American agroecosystems. Our results allow us to point to new ways to enhance self‐regulatory success, maximising the efficiency of crop production and reducing climate impacts. We have discussed important implications for crop management and climate change mitigation in an area where agriculture plays a key role in its socioeconomic and ecologic dimensions.     

The future of Iranian wetlands under climate change

Temporal changes in the area of 10 significant wetlands in Iran were determined using the remote sensing image of TM and ETM+ band 5 for a period of 15 years (1998–2012). The relationship between the annual time series of the area and the difference of precipitation and potential evaporation (P-E) was obtained for the wetlands using three evaporation methods. The area of the wetlands was predicted for 2050 using the best-fitting model and seven global climate models under four representative concentration pathways (a total of 28 climate scenarios). The area of five wetlands had a significant positive correlation with the P-E (R² > 0.72). The area of one wetland (Ghoorigol) is predicted to increase and the area of four wetlands (Bakhtegan, Chaghakhor, Parishan and Gavkhooni) is predicted to decrease in 2050 in comparison to the maximum area of the wetlands from 1998 to 2012 under all the climate scenarios. In comparison to the mean area of the wetlands (1998–2012), one wetland (Ghoorigol) is predicted to be larger and two wetlands (Gavkhooni and Parishan) are predicted to be smaller under all the climate scenarios. Two wetlands (Bakhtegan and Chaghakhor) are predicted to be larger under most of the climate scenarios in 2050. The Uromia wetland, the largest wetland in Iran, is predicted to become completely dry by 2032 if anthropogenic impacts continue similar to what occurred from 1998 to 2012.     

Potential distributional shifts in North America of allelopathic invasive plant species under climate change models

Predictive studies play a crucial role in the study of biological invasions of terrestrial plants under possible climate change scenarios. Invasive species are recognized for their ability to modify soil microbial communities and influence ecosystem dynamics. Here, we focused on six species of allelopathic flowering plants—Ailanthus altissima, Casuarina equisetifolia, Centaurea stoebe ssp. micranthos, Dioscorea bulbifera, Lantana camara, and Schinus terebinthifolia—that are invasive in North America and examined their potential to spread further during projected climate change. We used Species Distribution Models (SDMs) to predict future suitable areas for these species in North America under several proposed future climate models. ENMEval and Maxent were used to develop SDMs, estimate current distributions, and predict future areas of suitable climate for each species. Areas with the greatest predicted suitable climate in the future include the northeastern and the coastal northwestern regions of North America. Range size estimations demonstrate the possibility of extreme range loss for these invasives in the southeastern United States, while new areas may become suitable in the northeastern United States and southeastern Canada. These findings show an overall northward shift of suitable climate during the next few decades, given projected changes in temperature and precipitation. Our results can be utilized to analyze potential shifts in the distribution of these invasive species and may aid in the development of conservation and management plans to target and control dissemination in areas at higher risk for potential future invasion by these allelopathic species.     

Vulnerability of South African animal taxa to climate change

The responsiveness of South African fauna to climate change events is poorly documented and not routinely incorporated into regional conservation planning. We model the likely range alterations of a representative suite of 179 animal species to climate change brought about by the doubling of CO₂ concentrations. This scenario is expected to cause a mean temperature increase of 2 °C. We applied a multivariate climate envelope approach and evaluated model performance using the most comprehensive bird data set. The results were encouraging, although model performance was inconsistent in the eastern coastal area of the country. The levels of climate change induced impacts on species ranges varied from little impact to local extinction. Some 17% of species expanded their ranges, 78% displayed range contraction (4–98%), 3% showed no response and 2% became locally extinct. The majority of range shifts (41%) were in an easterly direction, reflecting the east–west aridity gradient across the country. Species losses were highest in the west. Substantially smaller westward shifts were present in some eastern species. This may reflect a response to the strong altitudinal gradient in this region, or may be a model artifact. Species range change (composite measure reflecting range contraction and displacement) identified selected species that could act as climate change indicator taxa. Red‐data and vulnerable species showed similar responses but were more likely to display range change (58% vs. 43% for all species). Predictions suggest that the flagship, Kruger National Park conservation area may loose up to 66% of the species included in this analysis. This highlights the extent of the predicted range shifts, and indicates why conflicts between conservation and other land uses are likely to escalate under conditions of climate change.     

The climate change implications of offshoring Finnish pulp production to South America

Purpose  

Offshoring of pulpwood production outside Europe is more and more common, which increases transport distances and also changes production technologies, raw material supply and energy production profiles. In this paper, we aim to compare the life cycle greenhouse gas emissions of pulp production from Finnish boreal hardwood and from South American eucalyptus. Special emphasis was placed on analysing the contribution of transport to overall climate impacts.     

Impacts of past habitat loss and future climate change on the range dynamics of South African Proteaceae

Aim

To assess how habitat loss and climate change interact in affecting the range dynamics of species and to quantify how predicted range dynamics depend on demographic properties of species and the severity of environmental change.

Location

South African Cape Floristic Region.

Methods

We use data‐driven demographic models to assess the impacts of past habitat loss and future climate change on range size, range filing and abundances of eight species of woody plants (Proteaceae). The species‐specific models employ a hybrid approach that simulates population dynamics and long‐distance dispersal on top of expected spatio‐temporal dynamics of suitable habitat.

Results

Climate change was mainly predicted to reduce range size and range filling (because of a combination of strong habitat shifts with low migration ability). In contrast, habitat loss mostly decreased mean local abundance. For most species and response measures, the combination of habitat loss and climate change had the most severe effect. Yet, this combined effect was mostly smaller than expected from adding or multiplying effects of the individual environmental drivers. This seems to be because climate change shifts suitable habitats to regions less affected by habitat loss. Interspecific variation in range size responses depended mostly on the severity of environmental change, whereas responses in range filling and local abundance depended mostly on demographic properties of species. While most surviving populations concentrated in areas that remain climatically suitable, refugia for multiple species were overestimated by simply overlying habitat models and ignoring demography.

Main conclusions

Demographic models of range dynamics can simultaneously predict the response of range size, abundance and range filling to multiple drivers of environmental change. Demographic knowledge is particularly needed to predict abundance responses and to identify areas that can serve as biodiversity refugia under climate change. These findings highlight the need for data‐driven, demographic assessments in conservation biogeography.

     

The future of terrestrial mammals in the Mediterranean basin under climate change

The Mediterranean basin is considered a hotspot of biological diversity with a long history of modification of natural ecosystems by human activities, and is one of the regions that will face extensive changes in climate. For 181 terrestrial mammals (68% of all Mediterranean mammals), we used an ensemble forecasting approach to model the future (approx. 2100) potential distribution under climate change considering five climate change model outputs for two climate scenarios. Overall, a substantial number of Mediterranean mammals will be severely threatened by future climate change, particularly endemic species. Moreover, we found important changes in potential species richness owing to climate change, with some areas (e.g. montane region in central Italy) gaining species, while most of the region will be losing species (mainly Spain and North Africa). Existing protected areas (PAs) will probably be strongly influenced by climate change, with most PAs in Africa, the Middle East and Spain losing a substantial number of species, and those PAs gaining species (e.g. central Italy and southern France) will experience a substantial shift in species composition.     

Biodiversity loss under existing land use and climate change: an illustration using northern South America

Aim Species richness depends on climate and land use. Maintaining locations with favourable climate and land‐use patterns is critical for protecting biodiversity because the loss of either can reduce the species richness that an area supports. Currently, the Guiana Shield (GS) receives abundant precipitation and has relatively light land use. For species richness this constitutes a good–good combination of climate and land use, respectively. In contrast, much of eastern Brazil receives low levels of precipitation and has heavy land use, which is a bad–bad combination for species richness. Thus, the current distribution of precipitation and land use in northern South America is relatively favourable for biodiversity. Palaeoclimate and model studies suggest, however, that the precipitation patterns for the two regions have switched before and could switch in response to greenhouse gas emissions. This paper examines the potential consequences of reconfiguring climate with respect to existing land‐use patterns using South America as an example. Location South America north of 20° S and east of the Andes. Methods Ecosystem structure and function are modelled under (1) historical climate and (2) altered precipitation following a shift in the location of the Inter‐Tropical Convergence Zone (ITCZ). The distribution of precipitation, biomes, net primary productivity (NPP) and land use are then used to predict levels of species richness under the two climate scenarios. Results Climate changes could shift the distribution of vegetation and NPP such that conditions favourable for species richness in the GS region disappear. If land‐use patterns were not prohibitive in eastern Brazil, the improved climate conditions there could compensate for the GS loss (assuming migratory barriers are overcome). Instead, existing land‐use patterns cause the combined species richness projected for the two regions to plummet. Main conclusions Human activities will alter current configurations of land use and climate throughout the world. For species richness, new configurations are likely to include both positive and negative combinations of climate and land use. However, the irreversibility of past extinctions due to land‐use patterns loads the dice against species richness.     

未来气候变化下两种红景天植物的脆弱性

气候变化对全球的物种多样性有深远影响, 尤其是对高山物种多样性。研究未来气候变化下物种的灭绝风险对生物多样性保护具有重要的意义。本文针对青藏高原的2种重要药用植物大花红景天(Rhodiola crenulata)和菊叶红景天(R. chrysanthemifolia), 利用气候生态位因子分析法研究了它们对气候变化的敏感性、暴露性和脆弱性, 讨论了2种“共享社会经济途径” (SSP2-45和SSP5-85)情景下的未来气候对这2个物种脆弱性的影响。同时计算了2种红景天的气候生态位的边缘性和特化性, 通过主成分分析法对其气候生态位进行了二维可视化, 并分析了它们的气候变化脆弱性与气候生态位之间的关系。结果表明, 未来气候变化情景下2种红景天在其分布区都显示出西部脆弱性高而东部脆弱性低的特征, 而脆弱性都表现为较低的横断山脉地区将成为其未来气候避难所。2种红景天在SSP5-85气候情景下的脆弱性高于SSP2-45, 资源和能源密集型社会经济途径(即SSP5-85)将会增大物种的灭绝风险。此外, 被《中国物种红色名录》评估为无危的菊叶红景天的气候变化脆弱性反而大于被评估为濒危的大花红景天。生态位因子分析结果表明大花红景天的生态位边缘性和特化性都低于菊叶红景天, 研究推断同地区不同物种的气候变化脆弱性主要由物种的气候生态位决定。     

Global diversity patterns of larger benthic foraminifera under future climate change

Global warming threatens the viability of tropical coral reefs and associated marine calcifiers, including symbiont-bearing larger benthic foraminifera (LBF). The impacts of current climate change on LBF are debated because they were particularly diverse and abundant during past warm periods. Studies on the responses of selected LBF species to changing environmental conditions reveal varying results. Based on a comprehensive review of the scientific literature on LBF species occurrences, we applied species distribution modeling using Maxent to estimate present-day and future species richness patterns on a global scale for the time periods 2040–2050 and 2090–2100. For our future projections, we focus on Representative Concentration Pathway 6.0 from the Intergovernmental Panel on Climate Change, which projects mean surface temperature changes of +2.2°C by the year 2100. Our results suggest that species richness in the Central Indo-Pacific is two to three times higher than in the Bahamian ecoregion, which we have identified as the present-day center of LBF diversity in the Atlantic. Our future predictions project a dramatic temperature-driven decline in low-latitude species richness and an increasing widening bimodal latitudinal pattern of species diversity. While the central Indo-Pacific, now the stronghold of LBF diversity, is expected to be most pushed outside of the currently realized niches of most species, refugia may be largely preserved in the Atlantic. LBF species will face large-scale non-analogous climatic conditions compared to currently realized climate space in the near future, as reflected in the extensive areas of extrapolation, particularly in the Indo-Pacific. Our study supports hypotheses that species richness and biogeographic patterns of LBF will fundamentally change under future climate conditions, possibly initiating a faunal turnover by the late 21st century.     

Protected areas offer refuge from invasive species spreading under climate change

Protected areas (PAs) are intended to provide native biodiversity and habitats with a refuge against the impacts of global change, particularly acting as natural filters against biological invasions. In practice, however, it is unknown how effective PAs will be in shielding native species from invasions under projected climate change. Here, we investigate the current and future potential distributions of 100 of the most invasive terrestrial, freshwater, and marine species in Europe. We use this information to evaluate the combined threat posed by climate change and invasions to existing PAs and the most susceptible species they shelter. We found that only a quarter of Europe's marine and terrestrial areas protected over the last 100 years have been colonized by any of the invaders investigated, despite offering climatically suitable conditions for invasion. In addition, hotspots of invasive species and the most susceptible native species to their establishment do not match at large continental scales. Furthermore, the predicted richness of invaders is 11%–18% significantly lower inside PAs than outside them. Invasive species are rare in long‐established national parks and nature reserves, which are actively protected and often located in remote and pristine regions with very low human density. In contrast, the richness of invasive species is high in the more recently designated Natura 2000 sites, which are subject to high human accessibility. This situation may change in the future, since our models anticipate important shifts in species ranges toward the north and east of Europe at unprecedented rates of 14–55 km/decade, depending on taxonomic group and scenario. This may seriously compromise the conservation of biodiversity and ecosystem services. This study is the first comprehensive assessment of the resistance that PAs provide against biological invasions and climate change on a continental scale and illustrates their strategic value in safeguarding native biodiversity.     

Projecting the future of an alpine ungulate under climate change scenarios

Climate change represents a primary threat to species persistence and biodiversity at a global scale. Cold adapted alpine species are especially sensitive to climate change and can offer key “early warning signs” about deleterious effects of predicted change. Among mountain ungulates, survival, a key determinant of demographic performance, may be influenced by future climate in complex, and possibly opposing ways. Demographic data collected from 447 mountain goats in 10 coastal Alaska, USA, populations over a 37‐year time span indicated that survival is highest during low snowfall winters and cool summers. However, general circulation models (GCMs) predict future increase in summer temperature and decline in winter snowfall. To disentangle how these opposing climate‐driven effects influence mountain goat populations, we developed an age‐structured population model to project mountain goat population trajectories for 10 different GCM/emissions scenarios relevant for coastal Alaska. Projected increases in summer temperature had stronger negative effects on population trajectories than the positive demographic effects of reduced winter snowfall. In 5 of the 10 GCM/representative concentration pathway (RCP) scenarios, the net effect of projected climate change was extinction over a 70‐year time window (2015–2085); smaller initial populations were more likely to go extinct faster than larger populations. Using a resource selection modeling approach, we determined that distributional shifts to higher elevation (i.e., “thermoneutral”) summer range was unlikely to be a viable behavioral adaptation strategy; due to the conical shape of mountains, summer range was expected to decline by 17%–86% for 7 of the 10 GCM/RCP scenarios. Projected declines of mountain goat populations are driven by climate‐linked bottom‐up mechanisms and may have wide ranging implications for alpine ecosystems. These analyses elucidate how projected climate change can negatively alter population dynamics of a sentinel alpine species and provide insight into how demographic modeling can be used to assess risk to species persistence.     

Priority threat management of invasive animals to protect biodiversity under climate change

Climate change is a major threat to global biodiversity, and its impacts can act synergistically to heighten the severity of other threats. Most research on projecting species range shifts under climate change has not been translated to informing priority management strategies on the ground. We develop a prioritization framework to assess strategies for managing threats to biodiversity under climate change and apply it to the management of invasive animal species across one‐sixth of the Australian continent, the Lake Eyre Basin. We collected information from key stakeholders and experts on the impacts of invasive animals on 148 of the region's most threatened species and 11 potential strategies. Assisted by models of current distributions of threatened species and their projected distributions, experts estimated the cost, feasibility, and potential benefits of each strategy for improving the persistence of threatened species with and without climate change. We discover that the relative cost‐effectiveness of invasive animal control strategies is robust to climate change, with the management of feral pigs being the highest priority for conserving threatened species overall. Complementary sets of strategies to protect as many threatened species as possible under limited budgets change when climate change is considered, with additional strategies required to avoid impending extinctions from the region. Overall, we find that the ranking of strategies by cost‐effectiveness was relatively unaffected by including climate change into decision‐making, even though the benefits of the strategies were lower. Future climate conditions and impacts on range shifts become most important to consider when designing comprehensive management plans for the control of invasive animals under limited budgets to maximize the number of threatened species that can be protected.     

Thermal controls of Yellowstone cutthroat trout and invasive fishes under climate change

We combine large observed data sets and dynamically downscaled climate data to explore historic and future (2050–2069) stream temperature changes over the topographically diverse Greater Yellowstone Ecosystem (elevation range = 824–4017 m). We link future stream temperatures with fish growth models to investigate how changing thermal regimes could influence the future distribution and persistence of native Yellowstone cutthroat trout (YCT) and competing invasive species. We find that stream temperatures during the recent decade (2000–2009) surpass the anomalously warm period of the 1930s. Climate simulations indicate air temperatures will warm by 1 °C to >3 °C over the Greater Yellowstone by mid‐21st century, resulting in concomitant increases in 2050–2069 peak stream temperatures and protracted periods of warming from May to September (MJJAS). Projected changes in thermal regimes during the MJJAS growing season modify the trajectories of daily growth rates at all elevations with pronounced growth during early and late summer. For high‐elevation populations, we find considerable increases in fish body mass attributable both to warming of cold‐water temperatures and to extended growing seasons. During peak July to August warming, mid‐21st century temperatures will cause periods of increased thermal stress, rendering some low‐elevation streams less suitable for YCT. The majority (80%) of sites currently inhabited by YCT, however, display minimal loss (<10%) or positive changes in total body mass by midcentury; we attribute this response to the fact that many low‐elevation populations of YCT have already been extirpated by historical changes in land use and invasions of non‐native species. Our results further suggest that benefits to YCT populations due to warmer stream temperatures at currently cold sites could be offset by the interspecific effects of corresponding growth of sympatric, non‐native species, underscoring the importance of developing climate adaptation strategies that reduce limiting factors such as non‐native species and habitat degradation.     

The fate of Meconopsis species in the Tibeto‐Himalayan region under future climate change

High‐mountain areas such as the Tibeto‐Himalayan region (THR) host cold‐adapted biota expected to be sensitive to anthropogenic climate change. Meconopsis is a representative endangered genus confined to alpine meadow or subnival habitats in the THR. We used climate‐niche factor analysis to study the vulnerability of ten Meconopsis species to climate change, comparing current climate (representative of 1960–1990) to future climate scenarios (2070: average 2061–2080). For these ten Meconopsis species, we then identified potential future climate refugia and determined optimal routes for each species to disperse to the proposed refugia. Our results indicate that for the ten Meconopsis species, the regions with low vulnerability to climate change in the THR are the central Qinghai‐Tibet Plateau, the Hengduan Mountains (HDM), the eastern Himalayas, and the West Qinling Mountain (WQL), and can be considered potential future climate refugia. Under future climate change, we found for the ten Meconopsis species potential dispersal routes to three of the four identified refugia: the HDM, the eastern Himalayas, and the WQL. Our results suggest that past refugia on the THR will also be the future climate refugia for the ten Meconopsis species, and these species may potentially persist in multiple future climate refugia, likely reducing risks from climate change. Furthermore, climate change may affect the threat ranking of Red Listed Species for Meconopsis species, as Least Concern species were estimated to become more vulnerable to climate change than the only Near Threatened species.     

Predicting range shifts of Davidia involucrata Ball. under future climate change

Understanding and predicting how species will respond to climate change is crucial for biodiversity conservation. Here, we assessed future climate change impacts on the distribution of a rare and endangered plant species, Davidia involucrate in China, using the most recent global circulation models developed in the sixth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC6). We assessed the potential range shifts in this species by using an ensemble of species distribution models (SDMs). The ensemble SDMs exhibited high predictive ability and suggested that the temperature annual range, annual mean temperature, and precipitation of the driest month are the most influential predictors in shaping distribution patterns of this species. The projections of the ensemble SDMs also suggested that D. involucrate is very vulnerable to future climate change, with at least one‐third of its suitable range expected to be lost in all future climate change scenarios and will shift to the northward of high‐latitude regions. Similarly, at least one‐fifth of the overlap area of the current nature reserve networks and projected suitable habitat is also expected to be lost. These findings suggest that it is of great importance to ensure that adaptive conservation management strategies are in place to mitigate the impacts of climate change on D. involucrate.     

Endophytes of native grasses from South America: Biodiversity and ecology

We review and present preliminary results of studies on cool-season grass endophytes native to South America. These fungi have been studied only in Argentina, where they have been detected in 36 native grass species. The hybrid Neotyphodium tembladerae is present in an extremely wide host range found in diverse environmental conditions, but some other endophytes seem to be strictly associated with one host species in a particular environment. In host species that inhabit different environments, the incidence of endophytes is highly variable among populations and in most of the cases is clearly associated with environmental conditions. In these native grasses, Neotyphodium presents a mutualistic behaviour, conferring enhanced growth, promoting the symbiosis with arbuscular mycorrhizal fungi, and inhibiting growth of pathogenic fungi. In native forage grasses, preliminary analyses indicate that some Argentinian endophytes can produce lolines but are unlikely to produce lolitrem B or ergot alkaloids.