Field ecology has been included in a ‘replication crisis’ that extends across many scientific disciplines. However, the underlying concepts of replication, reproducibility and replicability are not ...always clearly distinguished, and complicate the identification of best practices. Furthermore, conducting experiments under the high variability of natural field conditions reduces the capacity for replication relative to other biological disciplines working under controlled conditions. Field ecologists are therefore facing a significant challenge in assessing the replicability of their research with implications for overall confidence in study outcomes.
Through a review of the literature, we discuss several related aspects of experimental design that can enhance confidence in scientific outcomes. Specifically, we describe sample replication (repeat sample), within‐study replication (repeat experiment) and between‐study replication (repeat study) and how each can be used within field ecology. Since perfect between‐study replication (i.e. direct replication) is generally not possible in field ecology, we suggest more explicit use of conceptual replication would enhance confidence in scientific outcomes. However, such changes require cultural shifts in practice among all participants in the scientific enterprise.
We suggest several tangible steps could be taken to improve confidence in ecological research: (a) increase the use of within‐study replication before publication, (b) increase replicability for aspects that we can control (e.g. pre‐register experiments, open data, publish code), (c) divest from novelty as the primary criterion for publication in leading ecological journals and invest in experimental design, (d) be sceptical of contradictory findings from studies testing similar research questions and (e) create a publishing environment that encourages more conceptual replication studies.
We believe adopting these practices will increase the confidence in results for field ecology. There are critical obstacles that could prevent some scientists from increasing within‐study or between‐study replication, including short‐term funding mechanisms and the prospect of fewer publications. We suggest strategies to mitigate negative impacts to researchers, such as leading journals piloting new article categories and explicit mention of experimentally linked studies. We acknowledge that adopting greater replication in field ecology will require significant changes to cultural practices, but there are clear benefits for improving our confidence in science.
L'ecologia del campo è stata inclusa in una "crisi di replicazione" che si estende a molte discipline scientifiche. Tuttavia, i concetti sottostanti di replica, riproducibilità, e replicabilità non sono sempre chiaramente distinti e complicano l'identificazione delle migliori pratiche. Inoltre, condurre esperimenti sotto l'elevata variabilità delle condizioni del campo naturale riduce la capacità di replicazione rispetto ad altre discipline biologiche che lavorano in condizioni controllate. Gli ecologisti sul campo si trovano quindi ad affrontare una sfida significativa nel valutare la replicabilità della loro ricerca con implicazioni per la fiducia complessiva nei risultati dello studio.
Utilizzando recensione della letteratura, discutiamo diversi aspetti correlati del disegno sperimentale che possono aumentare la fiducia nei risultati scientifici. In particolare, descriviamo la replica del campione (ripetizione del campione), la replica all'interno dello studio (ripetizione dell'esperimento), e la replica tra gli studi (ripetizione dello studio) e come ciascuna può essere utilizzata nell'ecologia del campo. Poiché la replica perfetta tra gli studi (cioè la replica diretta) non è generalmente possibile nell'ecologia sul campo, suggeriamo che un uso più esplicito della replica concettuale aumenterebbe la fiducia nei risultati scientifici. Tuttavia, tali cambiamenti richiedono cambiamenti culturali nella pratica tra tutti i partecipanti all'impresa scientifica.
Suggeriamo che si potrebbero intraprendere diversi passi tangibili per migliorare la fiducia nella ricerca ecologica: (1) aumentare l'uso della replicazione all'interno dello studio prima della pubblicazione, (2) aumentare la replicabilità per gli aspetti che possiamo controllare (ad es. Esperimenti pre‐registrati, dati aperti, pubblicazione codice), (3) disinvestire dalla novità come criterio principale per la pubblicazione nelle principali riviste ecologiche e investire nella progettazione sperimentale, (4) essere scettici sui risultati contraddittori di studi che testano domande di ricerca simili, e (5) creare un ambiente di pubblicazione che incoraggia una replica più concettuale studi.
Riteniamo che l'adozione di queste pratiche aumenterà la fiducia nei risultati per l'ecologia sul campo. Esistono ostacoli critici che potrebbero impedire ad alcuni scienziati di aumentare la replica all'interno dello studio o tra gli studi, compresi i meccanismi di finanziamento a breve termine e la prospettiva di un minor numero di pubblicazioni. Suggeriamo strategie per mitigare gli impatti negativi ai ricercatori, come le principali riviste che sperimentano nuove categorie di articoli e la menzione esplicita di studi collegati sperimentalmente. Riconosciamo che l'adozione di una maggiore replica nell'ecologia sul campo richiederà cambiamenti significativi alle pratiche culturali, ma ci sono chiari vantaggi per migliorare la nostra fiducia nella scienza.
Lake ice is an important socio-economic resource that is threatened by climate change. The cover and duration of lake ice are expected to decline as air temperatures warm in the coming decades, ...disrupting a previously reliable source of income for many activities dependent on lake ice. The economic consequences of climate-induced lake ice loss remain unexplored, creating a significant research gap. The purpose of this study was to quantify the monetary spending associated with lake ice and how climate change may impact that value. Using a series of General Circulation Models (GCMs), greenhouse gas emissions scenarios, and models for lake ice cover, we predicted changes in lake ice by the end of the 21st century for the Northern Hemisphere. We also synthesized examples of spending associated with lake ice activities and discussed the potential implications expected with declining ice cover. We found that lake ice will decrease in area by 44,000-177,000 km.sup.2 and shorten in duration by 13-43 days by 2100. Using 31 examples of revenue from lake ice, we found that lake ice generates spending of over USD 2.04 billion to local communities and economies. We also found that countries predicted to experience the greatest ice loss by the end of the century are those that currently have the largest GDP, highest greenhouse gas emissions, and are most dependent on freshwater withdrawal. Our findings confirm predicted losses in lake ice that are expected because of climate change and quantify some of the potential consequences for local communities. Here we highlight lake ice as another casualty of human-caused climate change that will have profound socio-economic implications.
Snow cover is an extremely variable but critical component of alpine environments. We use long term population data on multiple small populations of the alpine butterfly Parnassius smintheus, ...combined with high‐resolution satellite imagery of meadows, to show a strong link between fine‐scale spatial and temporal variation in early‐winter snow cover and annual change in butterfly population size, accounting for up to 80 percent of the variation in annual population change. Snow cover in early winter for each meadow is the best predictor of annual adult population change, despite being estimated for a relatively short time‐window in late November. We identify a means by which subpopulation response to a local, short‐term weather variable can be assessed over a large spatial extent, but also at a resolution relevant to the biology and local dynamics of this alpine species.
Deserts are subject to significant anthropogenic pressure. The capacity to buffer against changes in the local environment and biodiversity are critical for ecosystem functioning. Foundation species ...can be a solution to rapidly assess ecological function and provide a simple nature‐based solution to protect against continuing biodiversity losses. A foundation species is defined as a species that exerts and promotes a positive set of processes for the biotic network. Two different shrub species in the central drylands of California were used to assay a potential buffer for plant species richness and to examine the species‐specificity of foundation facilitation. A five‐year dataset in two distinct regions differing in aridity was used to test the hypothesis that the direct effects of foundation plants facilitate other plant species and buffer diversity losses to a changing climate. The predicted positive effects of both shrub species on species richness increased with increasing local temperatures sampled. Finally, projected temperature increases for the region in trained Bayesian models demonstrated that both shrub species can profoundly increase in their capacity to facilitate plant species richness. Colloquially, this positive ecological effect can be described as the patronus charm hypothesis because regardless of the form of the protector, shrub species provided a talisman against local loss of richness driven by temperature increases.
Cities are growing in density and coverage globally, increasing the value of green spaces for human health and well-being. Understanding the interactions between people and green spaces is also ...critical for biological conservation and sustainable development. However, quantifying green space use is particularly challenging. We used an activity index of anonymized GPS data from smart devices provided by Mapbox (www.mapbox.com) to characterize human activity in green spaces in the Greater Toronto Area, Canada. The goals of our study were to describe i) a methodological example of how anonymized GPS data could be used for human-nature research and ii) associations between park features and human activity. We describe some of the challenges and solutions with using this activity index, especially in the context of green spaces and biodiversity monitoring. We found the activity index was strongly correlated with visitation records (i.e., park reservations) and that these data are useful to identify high or low-usage areas within green spaces. Parks with a more extensive trail network typically experienced higher visitation rates and a substantial proportion of activity remained on trails. We identified certain land covers that were more frequently associated with human presence, such as rock formations, and find a relationship between human activity and tree composition. Our study demonstrates that anonymized GPS data from smart devices are a powerful tool for spatially quantifying human activity in green spaces. These could help to minimize trade-offs in the management of green spaces for human use and biological conservation will continue to be a significant challenge over the coming decades because of accelerating urbanization coupled with population growth. Importantly, we include a series of recommendations when using activity indexes for managing green spaces that can assist with biomonitoring and supporting sustainable human use.
Climate change profoundly influences plants and animals in all ecosystems including drylands such as semi-arid and arid scrublands and grasslands. At the peak of an extended megadrought in the ...Southwestern USA, the microclimatic refuges provided by foundation plant species and through associated vegetation were examined. Shrubs and open interstitial spaces without a canopy but with annual plants were instrumented in 2016 and the wet season of 2017 in the central drylands of California. In both years and all seasons tested, vegetation significantly mediated fine-scale near-surface air temperature and relative soil moisture content-defined here as microclimate. The foundation species with other vegetation provided the most significant thermal refuge potential capacity for other plants and animals, but there was variation by growing season. Soil moisture content was frequently increased by the direct canopy effects of shrubs. This evidence suggests that the climate many plants and animals experience, even during an extended megadrought, is mediated by the local plants in highly impacted drylands with anthropogenic disturbance and significant water-induced challenges. Foundation species such as shrubs in drylands function as a potent starting point in examining the ecological relevance of climate at scales germane to many species locally. An ecological framework for climate resilience using shrubs will improve conservation and restoration planning in drylands.
Dominant vegetation in many ecosystems is an integral component of structure and habitat. In many drylands, native shrubs function as foundation species that benefit other plants and animals. ...However, invasive exotic plant species can comprise a significant proportion of the vegetation. In Central California drylands, the facilitative shrub Ephedra californica and the invasive Bromus rubens are widely dispersed and common. Using comprehensive survey data structured by shrub and open gaps for the region, we compared network structure with and without this native shrub canopy and with and without the invasive brome. The presence of the invasive brome profoundly shifted the network measure of centrality in the microsites structured by a shrub canopy (centrality scores increased from 4.3 under shrubs without brome to 6.3, i.e. a relative increase of 42%). This strongly suggests that plant species such as brome can undermine the positive and stabilizing effects of native foundation plant species provided by shrubs in drylands by changing the frequency that the remaining species connect to one another. The net proportion of positive and negative associations was consistent across all microsites (approximately 50% with a total of 14% non-random co-occurrences on average) suggesting that these plant-plant networks are rewired but not more negative. Maintaining resilience in biodiversity thus needs to capitalize on protecting native shrubs whilst also controlling invasive grass species particularly when associated with shrubs.
Environmental extremes resulting from a changing climate can have profound implications for plant interactions in desert communities. Positive interactions can buffer plant communities from abiotic ...stress and consumer pressure caused by climatic extremes, but limited research has explored this empirically.
We tested the hypothesis that the mechanism of shrub facilitation on an annual plant community can change with precipitation extremes in deserts. During years of extreme drought and above-average rainfall in a desert, we measured plant interactions and biomass while manipulating a soil moisture gradient and reducing consumer pressure.
Shrubs facilitated the annual plant community at all levels of soil moisture through reductions in microclimatic stress in both years and herbivore protection in the wet year only. Shrub facilitation and the high rainfall year contributed to the dominance of a competitive annual species in the plant community.
Precipitation patterns in deserts determine the magnitude and type of facilitation mechanisms. Moreover, shrub facilitation mediates the interspecific competition within the associated annual community between years with different rainfall amounts. Examining multiple drivers during extreme climate events is a challenging area of research, but it is a necessary consideration given forecasts predicting that these events will increase in frequency and magnitude.
Human experiences with nature are important for our culture, economy, and health. Anthropogenically-driven climate change is causing widespread shifts in biodiversity and resident urban wildlife are ...no exception. We modelled over 2,000 animal species to predict how climate change will impact terrestrial wildlife within 60 Canadian and American cities. We found evidence of an impending great urban shift where thousands of species will disappear across the selected cities, being replaced by new species, or not replaced at all. Effects were largely species-specific, with the most negatively impacted taxa being amphibians, canines, and loons. These predicted shifts were consistent across scenarios of greenhouse gas emissions, but our results show that the severity of change will be defined by our action or inaction to mitigate climate change. An impending massive shift in urban wildlife will impact the cultural experiences of human residents, the delivery of ecosystem services, and our relationship with nature.
Water quality degradation is one of the largest threats to freshwater ecosystems. Nutrient inputs, land use changes, and climate are expected to be the most important drivers of water quality ...degradation. Here, we quantify the relative influence of nutrient inputs, climate, and lake geomorphometry on primary production in freshwater lakes globally, using chlorophyll
a
(chla) as a proxy. We used a large lake chlorophyll database that included chla and total phosphorus, in addition to lake geomorphometric variables (mean depth, watershed area, elevation, surface area, volume, residence time) and climate (air temperature, precipitation, cloud cover, solar radiation) for 2561 freshwater lakes around the globe. Our model was able to explain 60% of the variation in chla concentrations. Of that, total phosphorus (TP) explained 42%, a combination of climate variables explained 38%, and geomorphometrics explained 20% of the variation. Although there have been increased efforts and regulations in place for land use and farming, nutrient inputs continue to be the leading cause of primary production in lakes. However, the influence of climatic variables acting synergistically (temperature, precipitation, cloud cover and solar radiation) is nearly equal to that of total phosphorus, suggesting nutrient management efforts are not sufficient alone to mitigate water quality degradation. Our findings underscore the critical need to incorporate climate factors into water quality management given current climate change.
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