This study provides new species records (NRs) of macroalgal assemblages present in rocky habitats from the South Shetland Islands (SSI) and north-eastern Antarctic Peninsula (EAP), Weddell Sea. Surveys were conducted during the summers of 2013/2014 to 2017/2018 at Elephant, Deception, Half Moon and Vega islands. Data from the present study and those available in the literature from the western Antarctic Peninsula (WAP) were combined to provide an updated checklist, giving insights into macroecology and potential changes in thermohaline circulation patterns. A total of 48 macroalgal taxa were identified from our sampling, with eight representing NRs to the EAP sector of the Weddell Sea and five representing NRs to the SSI. Statistical differences among the assemblages from the SSI, WAP and EAP were identified. NRs, including opportunistic species and new information about the biogeographical distributions of species reported here, give insights into ecoregional connectivity and environmental changes. This study updates macroalgal diversity records in regions that are currently experiencing the impacts of climate change. Future and ongoing monitoring for conservation purposes is required to detect non-native species, new dispersal pathways and patterns related to thermohaline anomalies in Antarctic waters.

The frequency and intensity of extreme weather events represent a threat for biological diversity and are expected to increase in many regions over the following decades due to climate change. Our current knowledge about the impact of extreme weather events on the population dynamics of bird species is very limited. Here, we evaluated the impact of an extreme winter snowstorm on the abundance of 14 populations of the threatened Dupont’s Lark Chersophilus duponti, a resident bird whose European population is restricted to Spain. We found a drastic and significant population decline in the next reproductive season following the extreme weather event. During the control period (2017–2020) the species suffered an overall annual decline of 19.4% (±5.0, SE). However, the overall annual decline after the storm was 67.6% (±9.4, period 2019–2021), with a mean decline of 66.5% (±15.9) for seven populations monitored both the year before and the year after the snowstorm (period 2020–2021). The snow covered the ground for over 10 days in central and eastern Spain, which together with a subsequent extreme cold wave could have reduced the species ability to find food resources and properly thermoregulate, forcing the species to move to unknown areas. Indeed a few days after the storm, several individuals were reported in areas typically avoided. Such displacements may increase the mortality risk for dispersing individuals, besides the direct effects of the extreme cold event, such as thermal challenges to energy balance or a reduced immune function. We discuss the potential role that extreme weather events may have on the population dynamics and conservation of the species.

Ocean acidification (OA) refers to a global decline in the average pH of seawater driven by the absorption of atmospheric carbon dioxide (CO2). Marine macroalgae, while affected by this pH change, are also able to modify seawater pH through their own interaction with inorganic carbon in the carbonate system. Through this action, macroalgae-dominated habitats are potential refugia from OA for associated marine species. This review summarises the most prominent literature on the role of macroalgae in OA mitigation and the potential of macroalgal habitats to serve as OA refugia. It includes a brief overview of macroalgal distribution in an effort to illustrate where such refugia might be most prevalent. Macroalgae influence seawater carbonate chemistry through the absorption of CO2 and HCO3− during photosynthesis, raising surrounding seawater pH in the process. This transient effect on seawater chemistry could provide some respite from the negative effects of OA for many marine species. This refuge role varies over a range of scales along with macroalgal architecture, which varies in size from low-growing turfs to large canopy-forming stands. The associated pH changes can range over various temporal (daily and seasonal) and spatial (from centimetre to kilometre) scales. Areas of high macroalgal biomass are likely to play an important role as significant OA refugia. Such communities are distributed widely throughout the globe. Large brown macroalgae (Laminariales) dominated communities are common in temperate regions, while members of the Fucales are responsible for substantial macroalgal stands in warmer tropical regions. These marine fields and forests have great potential to serve as localised refuges from OA. While more work needs to be done to clarify the effect of macroalgal communities on seawater pH on a large scale, such refuge areas could become important considerations for the management of marine resources and in protected area selection.

Monitoring the prevalence and abundance of parasites over time is important for addressing their potential impact on host life histories, immunological profiles and their influence as a selective force. Only long-term ecological studies have the potential to shed light on both the temporal trends in infection prevalence and abundance and the drivers of such trends, because of their ability to dissect drivers that may be confounded over shorter time scales. Despite this, only a relatively small number of such studies exist. Here, we analysed changes in the prevalence and abundance of gastrointestinal parasites in the wild Soay sheep population of St. Kilda across 31 years. The host population density (PD) has increased across the study, and PD is known to increase parasite transmission, but we found that PD and year explained temporal variation in parasite prevalence and abundance independently. Prevalence of both strongyle nematodes and coccidian microparasites increased during the study, and this effect varied between lambs, yearlings and adults. Meanwhile, abundance of strongyles was more strongly linked to host PD than to temporal (yearly) dynamics, while abundance of coccidia showed a strong temporal trend without any influence of PD. Strikingly, coccidian abundance increased 3-fold across the course of the study in lambs, while increases in yearlings and adults were negligible. Our decades-long, intensive, individual-based study will enable the role of environmental change and selection pressures in driving these dynamics to be determined, potentially providing unparalleled insight into the drivers of temporal variation in parasite dynamics in the wild.

The Parc National du Banc d’Arguin in Mauritania hosts the largest concentrations of coastal waterbirds along the East Atlantic Flyway. In spite of this importance, a review of the changes in the numbers of waterbirds in the area is lacking since the first complete count in 1980. Here we analysed the seven complete waterbird counts made since then, and the additional yearly counts made in one subunit (Iwik region) since 2003. We present evidence for changes in the community composition of waterbirds over the past four decades. Total waterbird numbers showed a decrease between 1980 and 2017, with only Great White Pelican Pelecanus onocrotalus showing a significant increase in numbers. Five species showed significant declines: Long-tailed Cormorant Phalacrocorax africanus, Red Knot Calidris canutus, Bar-tailed Godwit Limosa lapponica, Eurasian Curlew Numenius arquata, and Western Marsh Harrier Circus aeruginosus. In the remaining species, the variation in numbers between counts was too large, and the number of complete counts too small, for trends to be detected. The yearly counts at Iwik region also showed sharp decreases in the numbers of Red Knot, Bar-tailed Godwit, and Marsh Harrier, but not of Long-tailed Cormorant and Eurasian Curlew. A multivariate analysis revealed a significant change in species composition over time, which was caused mainly by changes in the species depending on the intertidal mudflats for feeding (generally in decline) vs. the species depending on fish and crustaceans in the sublittoral and offshore zones (often showing increases).

Global sustainability challenges and their impact on society have been well-documented in recent years, such as more intense extreme weather events, environmental degradation, as well as ecosystem and biodiversity loss. These challenges require a united effort of scientists from multiple disciplines with stakeholders, including government, non-government organizations, corporate industry, and members of the general public, with the aim to generate integrated knowledge with real-world applicability. Yet, there continues to be challenges for these types of collaboration. In this commentary, we describe processes of collective unlearning that serve to decenter academia in collaborations leading to a more equitable positioning of practitioners engaged in collaborative global sustainability research.

A combination of geological and anthropogenic processes have rendered theU.S. Gulf Coast in general – and the Mississippi Delta in particular –extremely sensitive to coastal hazard. Thus, the Katrina disaster was not aquestion of ‘if’ but of ‘when’. This contribution outlines thegeo-environmental context of the Mississippi Delta that evolved during the20th century and set the stage for Hurricane Katrina’s devastation. Thisincludes a brief discussion of the processes responsible for coastal erosionand wetland loss, the proposed measures to combat these problems, and thepolicy decisions (or, rather, the lack thereof) made so far. A connection ismade with the 1953 storm surge that devastated the southwestern Netherlandsand had a profound impact on Dutch science and engineering by providing theimpetus for the widely known and highly praised Delta Plan, as well as forunprecedented studies of Holocene sea-level change. Whether a similar routewill be followed for the Gulf Coast is primarily dependent on the amount ofpolitical will. Results are presented of recent studies of crustal movementsin the Mississippi Delta that show surprising long-term stability of thePleistocene basement, evidence that could prove critical for decision makerswith regard to the rebuilding process. Finally, the neglect of theprecarious situation along the Gulf Coast by the federal government isviewed as a possible metaphor for current U.S. policies with respect toscience in general, and to global warming in particular.

Traditionally, islands have been used as ecological and biogeographical models because of their assumed ecological simplicity, reduced ecosystem size and isolation. The vast number of Earth's oceanic islands play a key role in maintaining global biodiversity and serve as a rich source of evolutionary novelty. Research into the factors determining diversity patterns on islands must disentangle natural phenomena from anthropogenic causes of habitat transformation, interruption and enhancement of biological fluxes and species losses and gains in these geographically and ecologically limited environments. The anthropogenic ecological forcing of communication through global transport has profound implications regarding island–continent links. Anthropogenic disturbances along continental margins and insular coasts contribute to shaping island biotas in ecological time, but also have evolutionary consequences of global resonance. Patterns of human landscape and resource use (geographical space and ecological communities and species), as well as increasing ecological connectivity of oceanic islands and mainland, are chief driving forces in island biogeography that should be reappraised. Global indirect effects of human activities (i.e. climate change) may also affect islands and interact with these processes. We review the implications of direct and indirect anthropogenic disturbances on island biotic patterns, focusing on island size, isolation and introduced exotic species, as well as the unsettled issue of oceanic island ecological vulnerability.

Forest fragmentation and climate change are among the most severe and pervasive forms of human impact. Yet, their combined effects on plant–insect herbivore interaction networks, essential components of forest ecosystems with respect to biodiversity and functioning, are still poorly investigated, particularly in temperate forests. We addressed this issue by analysing plant-insect herbivore networks (PIHNs) from understories of three managed beech forest habitats: small forest fragments (2.2–145 ha), forest edges and forest interior areas within three continuous control forests (1050–5600 ha) in an old hyper-fragmented forest landscape in SW Germany. We assessed the impact of forest fragmentation, particularly edge effects, on PIHNs and the resulting differences in robustness against climate change by habitat-wise comparison of network topology and biologically realistic extinction cascades of networks following scores of vulnerability to climate change for the food plant species involved. Both the topological network metrics (complexity, nestedness, trophic niche redundancy) and robustness to climate change strongly increased in forest edges and fragments as opposed to the managed forest interior. The nature of the changes indicates that human impacts modify network structure mainly via host plant availability to insect herbivores. Improved robustness of PIHNs in forest edges/small fragments to climate-driven extinction cascades was attributable to an overall higher thermotolerance across plant communities, along with positive effects of network structure. The impoverishment of PIHNs in managed forest interiors and the suggested loss of insect diversity from climate-induced co-extinction highlight the need for further research efforts focusing on adequate silvicultural and conservation approaches.

Patterns of climate and C4plant abundance in the southwestern United States during the last glaciation were evaluated from isotopic study of herbivore tooth enamel. Enamel δ13C values revealed a substantial eastward increase in C4plant consumption for Mammuthusspp., Bisonspp., Equusspp., and Camelopsspp. The δ13C values were greatest in Bisonspp. (−6.9 to +1.7‰) and Mammuthusspp. (−9.0 to +0.3‰), and in some locales indicated C4-dominated grazing. The δ13C values of Antilocaprids were lowest among taxa (−12.5 to −7.9‰) and indicated C3feeding at all sites. On the basis of modern correlations between climate and C4grass abundance, the enamel data imply significant summer rain in parts of southern Arizona and New Mexico throughout the last glaciation. Enamel δ18O values range from +19.0 to +31.0‰ and generally increase to the east. This pattern could point to a tropical or subtropical source of summer rainfall. At a synoptic scale, the isotope data indicate that interactions of seasonal moisture, temperature, and lowered atmospheric pCO2determined glacial-age C4abundance patterns.

Dandelion is a cosmopolitan weed of economic and environmental significance because of its negative effects on crop yield and the large amount of herbicides used for its control in agricultural, residential, and recreational areas in North America. Asexual dandelion plants, which are apomictic and produce genetically identical seeds, provide a great experimental model for biological studies, such as examination of its reproductive responses to global environmental changes. In a growth chamber experiment, we investigated how elevated CO2 affected reproduction and seed dispersal properties in dandelion. Dandelion plants were grown at ambient (370 µmol mol−1) or elevated (730 µmol mol−1) CO2 until reproductive maturity. Results showed that dandelion plants examined in our study produced 83% more inflorescences and 32% more achenes, i.e., single-seed fruits, per plant at elevated than at ambient CO2. Seeds from elevated CO2-grown plants were significantly heavier and had a higher germination percentage, leading to larger seedlings and earlier establishment in the subsequent generation. Furthermore, achenes from plants grown at elevated CO2 had characteristics, such as higher stalks at seed maturity, longer beaks, and larger pappi, which would increase the distance of seed dispersal by wind. In addition to these elevated CO2-induced changes in reproductive properties, dandelion has a number of inherent characteristics, e.g., high competitiveness and adaptations to disturbance, that would increase its vegetative and reproductive success in a higher CO2 environment. Consequently, dandelion can potentially become more widespread and noxious as atmospheric CO2 continues to rise because of human activities.

Palmer amaranth, a dioecious summer annual forb, originating in Sonoran desert washes, compromises crop yields in much of the southern United States and its range is expanding northward. Appropriate tactics for managing this weed proactively in the Upper Midwest will depend on characterizing its damage niche, the geographic range in which it can reduce crop yields. We implemented a common garden study in 2011 and 2012, planting eight accessions of Palmer amaranth from the southern and midwestern United States, into soybean crops in southern, central, and northern Illinois, at a population density of 8 plants m−2 with a biocontainment protocol. Once Palmer amaranth plants initiated flowering, they were removed and burned. Weed survival, flowering, and weed biomass were measured, in addition to soybean yield and weather data. Analyses indicated that Palmer amaranth's damage niche in Illinois soybean was independent of weed genotype or maternal environment. Despite competing only briefly, Palmer amaranth reduced soybean yields in all site–years, indicating its damage niche in Illinois, and much of the Midwest, is limited primarily by seed immigration rate. These results highlight the urgent need for weed managers to learn Palmer amaranth identification, prevent seed introduction, and maintain a policy of zero seed return.

We present new estimates on evaporation and groundwater recharge in the Badain Jaran Desert, western Inner Mongolia of northwestern China, based on a modified Penman Equation suitable for lakes in China. Geochemical data and water balance calculations suggest that local rainfall makes a significant contribution to groundwater recharge and that past lake-level variations in this desert environment should reflect palaeoclimatic changes. The chronology of lake-level change, established by radiocarbon and U-series disequilibrium dating methods, indicates high lake levels and a wetter climate beginning at ca. 10 ka and lasting until the late mid-Holocene in the Badain Jaran Desert. The greatest extension of lakes in the inter-dune depressions indicates that the water availability was greatest during the mid-Holocene. Relicts of Neolithic tools and pottery of Qijia Culture (2400–1900 BC) suggest relatively intensive human activity in the Badain Jaran Desert during the early and middle Holocene, supporting our interpretation of a less harsh environment. Wetter climates during the Holocene were likely triggered by an intensified East Asian summer monsoon associated with strong insolation.

Host-parasite interactions are an integral part of ecosystems that influence both ecological and evolutionary processes. Humans are currently altering environments the world over, often with drastic consequences for host-parasite interactions and the prevalence of parasites. The mechanisms behind the changes are, however, poorly known. Here, we explain how host-parasite interactions depend on two crucial steps – encounter rate and host-parasite compatibility – and how human activities are altering them and thereby host-parasite interactions. By drawing on examples from the literature, we show that changes in the two steps depend on the influence of human activities on a range of factors, such as the density and diversity of hosts and parasites, the search strategy of the parasite, and the avoidance strategy of the host. Thus, to unravel the mechanisms behind human-induced changes in host-parasite interactions, we have to consider the characteristics of all three parts of the interaction: the host, the parasite and the environment. More attention should now be directed to unfold these mechanisms, focusing on effects of environmental change on the factors that determine encounter rate and compatibility. We end with identifying several areas in urgent need of more investigations.

Fasciola hepatica is a pathogenic trematode parasite of ruminants with a global distribution. Here, we briefly review the current epidemiology of bovine fasciolosis in Europe and discuss the progress made over the last decade in the diagnosis, impact on production and prediction of F. hepatica in cattle. Advances in diagnosis have led to significantly improved coprological and serological methods to detect presence of infection. Diagnostic test results have been correlated with intensity of infection and associated production losses, unravelling the impact on carcass weight and milk yield in modern cattle production systems. The economic impact of fasciolosis may, however, go beyond the direct impacts on production as evidence shows that F. hepatica can modulate the immune response to some co-infections. Control of bovine fasciolosis remains hampered by the limitations of the currently available flukicidal drugs: few drugs are available to treat dairy cows, many have low efficacies against juvenile stages of F. hepatica and there is evidence for the development of drug resistance. This makes research into the prediction of risk periods, and thus the optimum application of available drugs more pertinent. In this field, the recent research focus has been on understanding spatial risk and delivering region-specific spatial distribution maps. Further advances in epidemiological and economic research on bovine fasciolosis are expected to deliver farm-specific economic assessments of disease impact, to leverage non-chemotherapeutic management options and to enhance a more targeted use of anthelmintics.

In 2001 the LIMNOPOLAR Project was launched with the aim of addressing the suitability of freshwater ecosystems as useful sentinels of climate change. In this project, an automatic weather station was deployed on Byers Peninsula (Livingston Island, South Shetland Islands) near several freshwater ecosystems under research. Here the multi-year data recorded are presented and compared with meteorological time series from the observatories at the Spanish Juan Carlos I Station, Deception Island and Bellingshausen Station. Lake freezing and thawing periods and snow cover are also investigated. The main results indicate that Byers Peninsula is affected by the very cloudy and wet Antarctic maritime climate. Mean annual temperature is -2.8°C and summer mean temperatures are above freezing. The region shows moderate winds over the year and with moderate, mostly liquid precipitation during the summer. There is a significant linear relationship with meteorological records obtained from Juan Carlos I Station located on the east of Livingston Island. Correlations between meteorological data from both sites are high but with colder and much windier conditions on Byers Peninsula. Therefore, the usefulness and accuracy of meteorological records in the interpretation of ecosystem dynamics are presented.