Temperature Tolerance and Stress Proteins as Mechanisms of Invasive Species Success

Invasive species are predicted to be more successful than natives as temperatures increase with climate change. However, few studies have examined the physiological mechanisms that theoretically underlie this differential success. Because correlative evidence suggests that invasiveness is related to the width of a species' latitudinal range, it has been assumed – but largely untested – that range width predicts breadth of habitat temperatures and physiological thermotolerances. In this study, we use empirical data from a marine community as a case study to address the hypotheses that (1) geographic temperature range attributes are related to temperature tolerance, leading to greater eurythermality in invasive species, and (2) stress protein expression is a subcellular mechanism that could contribute to differences in thermotolerance. We examined three native and six invasive species common in the subtidal epibenthic communities of California, USA. We assessed thermotolerance by exposing individuals to temperatures between 14°C and 31°C and determining the temperature lethal to 50% of individuals (LT50) after a 24 hour exposure. We found a strong positive relationship between the LT50 and both maximum habitat temperatures and the breadth of temperatures experience across the species' ranges. In addition, of the species in our study, invasives tended to inhabit broader habitat temperature ranges and higher maximum temperatures. Stress protein expression may contribute to these differences: the more thermotolerant, invasive species Diplosoma listerianum expressed higher levels of a 70-kDa heat-shock protein than the less thermotolerant, native Distaplia occidentalis for which levels declined sharply above the LT50. Our data highlight differences between native and invasive species with respect to organismal and cellular temperature tolerances. Future studies should address, across a broader phylogenetic and ecosystem scope, whether this physiological mechanism has facilitated the current success of invasive species and could lead to greater success of invasives than native species as global warming continues

Why Do Species Co-Occur? A Test of Alternative Hypotheses Describing Abiotic Differences in Sympatry versus Allopatry Using Spadefoot Toads

Areas of co-occurrence between two species (sympatry) are often thought to arise in regions where abiotic conditions are conducive to both species and are therefore intermediate between regions where either species occurs alone (allopatry). Depending on historical factors or interactions between species, however, sympatry might not differ from allopatry, or, alternatively, sympatry might actually be more extreme in abiotic conditions relative to allopatry. Here, we evaluate these three hypothesized patterns for how sympatry compares to allopatry in abiotic conditions. We use two species of congeneric spadefoot toads, Spea multiplicata and S. bombifrons, as our study system. To test these hypotheses, we created ecological niche models (specifically using Maxent) for both species to create a map of the joint probability of occurrence of both species. Using the results of these models, we identified three types of locations: two where either species was predicted to occur alone (i.e., allopatry for S. multiplicata and allopatry for S. bombifrons) and one where both species were predicted to co-occur (i.e., sympatry). We then compared the abiotic environment between these three location types and found that sympatry was significantly hotter and drier than the allopatric regions. Thus, sympatry was not intermediate between the alternative allopatric sites. Instead, sympatry occurred at one extreme of the conditions occupied by both species. We hypothesize that biotic interactions in these extreme environments facilitate co-occurrence. Specifically, hybridization between S. bombifrons females and S. multiplicata males may facilitate co-occurrence by decreasing development time of tadpoles. Additionally, the presence of alternative food resources in more extreme conditions may preclude competitive exclusion of one species by the other. This work has implications for predicting how interacting species will respond to climate change, because species interactions may facilitate survival in extreme habitats

Natural hazards in Australia: heatwaves

As part of a special issue on natural hazards, this paper reviews the current state of scientific knowledge of Australian heatwaves. Over recent years, progress has been made in understanding both the causes of and changes to heatwaves. Relationships between atmospheric heatwaves and large-scale and synoptic variability have been identified, with increasing trends in heatwave intensity, frequency and duration projected to continue throughout the 21st century. However, more research is required to further our understanding of the dynamical interactions of atmospheric heatwaves, particularly with the land surface. Research into marine heatwaves is still in its infancy, with little known about driving mechanisms, and observed and future changes. In order to address these knowledge gaps, recommendations include: focusing on a comprehensive assessment of atmospheric heatwave dynamics; understanding links with droughts; working towards a unified measurement framework; and investigating observed and future trends in marine heatwaves. Such work requires comprehensive and long-term collaboration activities. However, benefits will extend to the international community, thus addressing global grand challenges surrounding these extreme events

Spatiotemporal Variation in Avian Migration Phenology: Citizen Science Reveals Effects of Climate Change

A growing number of studies have documented shifts in avian migratory phenology in response to climate change, and yet there is a large amount of unexplained variation in the magnitude of those responses across species and geographic regions. We use a database of citizen science bird observations to explore spatiotemporal variation in mean arrival dates across an unprecedented geographic extent for 18 common species in North America over the past decade, relating arrival dates to mean minimum spring temperature. Across all species and geographic locations, species shifted arrival dates 0.8 days earlier for every °C of warming of spring temperature, but it was common for some species in some locations to shift as much as 3–6 days earlier per °C. Species that advanced arrival dates the earliest in response to warming were those that migrate more slowly, short distance migrants, and species with broader climatic niches. These three variables explained 63% of the interspecific variation in phenological response. We also identify a latitudinal gradient in the average strength of phenological response, with species shifting arrival earlier at southern latitudes than northern latitudes for the same degree of warming. This observation is consistent with the idea that species must be more phenologically sensitive in less seasonal environments to maintain the same degree of precision in phenological timing

Zoofolkloristika: Prvi uvidi na putu prema novoj disciplini

The author notes that new, more complex researches of connections between animals, nature and connections to humans are needed in Slovenian and European folklore, literature and cultural studies, due to new ecological and ethical findings in the wider social and cultural environment and a changing order of the world, which has moved the focus from anthropocentrism into ecocentrism. The discussion builds upon various theoretical discourses, new concepts and multidisciplinary knowledge, to create the foundations, guidelines and directions for a new academic discipline of zoofolkloristics. Furthermore, new theoretical and analytical discourses should enable zoofolkloristics to provide an insight into changes in human attitudes to animals, in both folklore and within traditional and contemporary ritual practices, or their redefinition, and at the same time exert influence upon legal safety of non-human subjectivities.Autorica polazi od tvrdnje da su potrebna nova, kompleksnija istraživanja veza između životinja, prirode i poveznica s ljudima u slovenskoj i europskoj folkloristici, znanosti o književnosti i kulturnim studijima, zbog novih ekoloških i etičkih uvida u širu društveno-kulturnu okolinu i promjene u svijetu, koje su dovele do promjene od antropocentrizma k ekocentrizmu. U radu se na temelju različitih teorijskih diskursa, novih pojmova i multidisciplinarnog znanja stvaraju temelji, smjernice i pravci istraživanja u novoj znanstvenoj disciplini zoofolkloristike. Autorica tvrdi da bi etnologija, folkloristika i znanost o književnosti mogle imati ključnu ulogu u razvoju ekološke svijesti, znanstvenih terenskih istraživanja i kulturne ekologije te tako omogućiti prelazak iz ekologije u eshatologiju. Rad započinje opisom percepcije životinja i odnosa ljudi i životinja, gdje autorica govori o temeljnim pojmovima koji utječu na uvođenje ove nove znanstvene discipline, kao što su: životinja kao ispitanik, individualni pristup životinji, sinantropski i antropofilni pogled na čovjeka i životinju te antropomorfizam. Zatim se govori o povijesnim i suvremenim filozofsko-antropološkim diskursima o ljudskom pogledu na životinju te o teoriji specizma. Autorica razmatra predmet nove discipline te kaže da je u centru istraživanja životinja u folkloru u najširem mogućem smislu, u svim sferama narodne kulture, što se proučava iz novih gledišta, nove percepcije i recepcije; u pjesmama, pričama, bajkama, basnama, predajama, poslovicama, izrekama, zagonetkama, šalama, narodnom jeziku, kulturnim praksama, narodnom teatru, mitologiji, narodnoj medicini pa čak i u narodnoj glazbi. Nadalje, autorica daje pregled kulturnih istraživanja životinja u Europi i Sloveniji, te pokazuje da su rasprave o životinjama uglavnom objavljivane u 21. stoljeću, što bi moglo označavati da je riječ o prelasku u novu paradigmu ili čak i novu ontologiju. Autorica se bavi metodološkim i teorijskim pitanjima i pravcima u zoofolklorističkim istraživanjima koje klasificira prema kritičkom diskursu. Rad završava pregledom ciljeva zoofolkloristike, za koju tvrdi da ne bi smjela postati znanstvena disciplina koja nema aktivan utjecaj na društvenopolitički prostor u kojem koegzistiraju ljudski i ne-ljudski subjektiviteti

Urban Biodiversity and Landscape Ecology: Patterns, Processes and Planning

Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world

Trace element fingerprinting of cockle (Cerastoderma edule) shells can reveal harvesting location in adjacent areas

Determining seafood geographic origin is critical for controlling its quality and safeguarding the interest of consumers. Here, we use trace element fingerprinting (TEF) of bivalve shells to discriminate the geographic origin of specimens. Barium (Ba), manganese (Mn), magnesium (Mg), strontium (Sr) and lead (Pb) were quantified in cockle shells (Cerastoderma edule) captured with two fishing methods (by hand and by hand-raking) and from five adjacent fishing locations within an estuarine system (Ria de Aveiro, Portugal). Results suggest no differences in TEF of cockle shells captured by hand or by hand-raking, thus confirming that metal rakes do not act as a potential source of metal contamination that could somehow bias TEF results. In contrast, significant differences were recorded among locations for all trace elements analysed. A Canonical Analysis of Principal Coordinates (CAP) revealed that 92% of the samples could be successfully classified according to their fishing location using TEF. We show that TEF can be an accurate, fast and reliable method to determine the geographic origin of bivalves, even among locations separated less than 1 km apart within the same estuarine system. Nonetheless, follow up studies are needed to determine if TEF can reliably discriminate between bivalves originating from different ecosystems