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Aim: Climate change impacts on biota are variable across sites, among species and throughout individual species' ranges. Niche theory predicts that population performance should decline as site climate becomes increasingly different from the species' climate niche centre, though studies find significant variation from these predictions. Here, we propose that predictions about climate responses can be improved by incorporating species' trait information. Location: Europe. Methods: We used observations of plant species abundance change over time to assess variation in climate difference sensitivity (CDS), defined as how species performance (colonization, extinction and abundance change) relates to the difference of site climate from the mean temperature and precipitation of each species' range. We then investigated if leaf economics, plant size and seed mass traits were associated with the species' CDS. Results: Species that performed better (e.g. increased in abundance) towards sites progressively cooler than their niche centre were shorter and had more resource-acquisitive leaves (i.e. lower leaf dry matter content or LDMC) relative to species with zero or the opposite pattern of temperature difference sensitivity. This result supports the hypothesis that if sites cooler than niche centres are more stressful for a species, then shorter stature is advantageous compared with taller species. The LDMC result suggests the environment selects for more resource-acquisitive leaf strategies towards relatively cooler climates with shorter growing seasons, counter to expectations that conservative strategies would be favoured in such environments. We found few consistent relationships between precipitation difference sensitivities and traits. Main Conclusions: The results supported key a priori foundations on how trait-based plant strategies dictate species responses to climate variation away from their niche centre. Furthermore, plant height emerged as the most consistent trait that varied with species CDS, suggesting height will be key for theory development around species response to climate change. publishedVersion

As Open Science practices become more commonplace, there is a need for the next generation of scientists to be well versed in these aspects of scientific research. Yet, many training opportunities for early career researchers (ECRs) could better emphasize or integrate Open Science elements. Field courses provide opportunities for ECRs to apply theoretical knowledge, practice new methodological approaches, and gain an appreciation for the challenges of real‐life research, and could provide an excellent platform for integrating training in Open Science practices. Our recent experience, as primarily ECRs engaged in a field course interrupted by COVID‐19, led us to reflect on the potential to enhance learning outcomes in field courses by integrating Open Science practices and online learning components. Specifically, we highlight the opportunity for field courses to align teaching activities with the recent developments and trends in how we conduct research, including training in: publishing registered reports, collecting data using standardized methods, adopting high‐quality data documentation, managing data through reproducible workflows, and sharing and publishing data through appropriate channels. We also discuss how field courses can use online tools to optimize time in the field, develop open access resources, and cultivate collaborations. By integrating these elements, we suggest that the next generation of field courses will offer excellent arenas for participants to adopt Open Science practices., Open Science methodology is becoming an increasingly important goal of scientific research. Yet, our higher education system does not necessarily reflect these developments, even though such methods are beneficial for the advancement of early career researchers. Here we highlight how field courses can be a valuable resource for early career researchers and our learning of best practice in Open Science methodology, and how online workflows can support this process.

Forest-dependent biodiversity is threatened throughout the tropics by habitat loss and land-use intensification of the matrix habitats. We resampled historic data on two moth families, known to play central roles in many ecosystem processes, to evaluate temporal changes in species richness and community structure in three protected forests in central Uganda in a rapidly changing matrix. Our results show some significant declines in the moth species richness and the relative abundance and richness of forest-dependent species over the last 20–40 years. The observed changes in species richness and composition among different forests, ecological types, and moth groups highlight the need to repeatedly monitor biodiversity even within protected and relatively intact forests. publishedVersion

Seed banks contribute to forest regeneration after disturbance, but less is known about fern spore banks, particularly in a paleotropical context. We sampled the buried seed and fern spore bank in Mabira Forest, a 300 km2 forest in central Uganda, to explore the effect of time since disturbance. Soil cores (5 cm depth) were taken from 39 plots across three different classes of ‘recovery’: (1) not disturbed since 1950; (2) logged between 1950 and 1980; and (3) cleared for agriculture between 1970 and 1990 but reforested since. Plant emergence was monitored in a glasshouse. We predicted that the seed bank would reflect time since disturbance, with more pioneer species in recently disturbed stands, and that the fern spore bank would reflect stand age less closely due to greater dispersal capacity. We recorded a median 752 seeds per square meter, most of which were trees; the most abundant species was the invasive tree Broussonetia papyrifera. The fern spore bank was twice as dense, but 95 percent of fern spores were of one species, Christella parasitica. Tree seed density was significantly affected by time since disturbance with fewer seeds in the older stands. Herb seed density, fern spore density, and species richness for all groups were not significantly affected by time since disturbance. Neither seed bank nor fern spore bank closely resembled the aboveground vegetation. We compared our results to existing literature on seed banks in tropical forests, finding that our densities are relatively high for African forests, but low compared to the Neotropics and Australia. RESUME Les banques de graines contribuent a la regeneration des forets apres perturbation, mais nous savons encore peu de choses au sujet des banques de spores de fougeres, particulierement dans un contexte paleotropical. Nous avons enregistre les graines ainsi que les spores de fougeres enterrees dans la foret de Mabira, une foret de 300 km² au centre de l'Ouganda, et explore l'impact du temps passe depuis une perturbation. Les echantillons de terre ont ete preleves jusqu’a 5 cm de profondeur dans 39 parcelles caracterisees par differents degres de “reconstruction”: non perturbee depuis 1950, exploitee entre 1950 et 1980, et deboisee pour des fins d'agriculture entre 1970 et 1990 puis reboisee. L’emergence a ete suivie dans une serre. Nous avons predit que la banque de graines allait refleter le temps passe depuis la perturbation, avec davantage d'especes pionnieres dans les parcelles recemment perturbees, mais que ce patron serait moins remarquable pour la banque de spores en raison de meilleures capacites de dispersion. Nous avons enregistre une mediane de 752 graines par metre carre, dons la plupart etaient des graines d'arbres ; la graine la plus abondante etait le petit arbre invasif Broussonetia papyrifera. La banque de spores de fougeres etait deux fois plus dense mais 95 pourcent de ces spores appartenaient a une seule espece, Christella parasitica. La densite de graines d'arbres etait significativement affectee par le temps passe depuis la perturbation, avec moins de graines dans les parcelles les plus anciennes. La densite de graines d'herbes, la densite de spores de fougeres et la richesse specifique pour tous les groupes n’etaient pas significativement affectees par le temps passe depuis la perturbation. Ni la banque de graines, ni la banque de spores de fougeres ne ressemblait vraiment a la vegetation de surface. Nous avons compare nos resultats a la litterature existant sur les banques de graines en foret tropicale, et trouve que nos densites etaient relativement fortes par rapport aux forets africaines, mais basses comparees aux forets neotropicales et australiennes.

Aim Fossil pollen spectra from lake sediments in central and western Mongolia have been used to interpret past climatic variations, but hitherto no suitable modern pollen–climate calibration set has been available to infer past climate changes quantitatively. We established such a modern pollen dataset and used it to develop a transfer function model that we applied to a fossil pollen record in order to investigate: (1) whether there was a significant moisture response to the Younger Dryas event in north-western Mongolia; and (2) whether the early Holocene was characterized by dry or wet climatic conditions. Location Central and western Mongolia. Methods We analysed pollen data from surface sediments from 90 lakes. A transfer function for mean annual precipitation (Pann) was developed with weighted averaging partial least squares regression (WA-PLS) and applied to a fossil pollen record from Lake Bayan Nuur (49.98° N, 93.95° E, 932 m a.s.l.). Statistical approaches were used to investigate the modern pollen–climate relationships and assess model performance and reconstruction output. Results Redundancy analysis shows that the modern pollen spectra are characteristic of their respective vegetation types and local climate. Spatial autocorrelation and significance tests of environmental variables show that the WA-PLS model for Pann is the most valid function for our dataset, and possesses the lowest root mean squared error of prediction. Main conclusions Precipitation is the most important predictor of pollen and vegetation distributions in our study area. Our quantitative climate reconstruction indicates a dry Younger Dryas, a relatively dry early Holocene, a wet mid-Holocene and a dry late Holocene.

Private forests harbor considerable biodiversity, however, they are under greater threat than reserved areas, particularly from urbanization, agriculture, and intense exploitation for timber and fuel wood. The extent to which they may act as habitats for biodiversity and how level of protection impacts trends in biodiversity and forest structure over time remain underresearched. We contribute to filling this research gap by resampling a unique data set, a detailed survey from 1990 of 22 forests fragments of different ownership status and level of protection near Kampala, Uganda. Eleven of the 22 fragments were lost over 20 years, and six of the remnants reduced in size. Forest structure and composition also showed dramatic changes, with six of the remnant fragments showing high temporal species turnover. Species richness increased in four of the remaining forests over the resample period. Forest ownership affected the fate of the forests, with higher loss in privately owned forests. Our study demonstrates that ownership affects the fate of forest fragments, with private forests having both higher rates of area loss, and of structural and compositional change within the remaining fragments. Still, the private forests contribute to the total forest area, and they harbor biodiversity including IUCN “vulnerable” and “endangered” species. This indicates the conservation value of the fragments and suggests that they should be taken into account in forest conservation and restoration. publishedVersion

We present an expanded training set of salt-marsh foraminifera for reconstructing Holocene relative sea-level change from 12 sites in New Jersey that represent varied physiographic environments. Seven groups of foraminifera are recognized, including four high- or transitional-marsh assemblages and a low-salinity assemblage. A weighted-averaging transfer function trained on this dataset was applied to a dated core from Barnegat Bay to reconstruct sea level with uncertainties of � 14% of tidal range. We evaluate the transfer function using seven tests. (1) Leave-one-site-out cross validation suggests that training sets of salt-marsh foraminifera are robust to spatial autocorrelation caused by sampling along transects. (2) Segment-wise analysis shows that the transfer function performs best at densely sampled elevations and overall estimates of model performance are over optimistic. (3) Dissimilarity and (4) non-metric multi-dimensional scaling evaluated the analogy between modern and core samples. The closest modern analogues for core samples were drawn from six sites demonstrating the necessity of a multi-site training set. (5) Goodness-of-fit statistics assessed the validity of reconstructions. (6) The transfer function failed a test of significance because of the unusual properties of some cores selected for sea-level reconstruction. (7) Agreement between reconstructed sea level and tide-gauge measurements demonstrates the transfer function's utility. Copyright # 2013 John Wiley & Sons, Ltd.

Palaeotemperature reconstructions based on radiocarbon-dated fossil pollen and chironomid stratigraphies obtained from Lake Gilltjarnen provide evidence of climate changes during the last 11 000 years in the boreal zone of northern central Sweden. The records show consistent trends during the early and mid-Holocene, indicating low temperatures at 11 000–10 000 cal. yr BP, followed by a rising trend and a period of maximum values from about 7000 to 4000 cal. yr BP. At 3000 cal. yr BP the chironomid-inferred temperature values rise abruptly, deviating from the late-Holocene cooling trend indicated by the pollen-based reconstruction and most of the other palaeotemperature records from central Scandinavia, probably as a result of local limnological changes in Lake Gilltjarnen and its catchment. Comparison of the present results with a lake-level reconstruction from Lake Ljustjarnen, ca. 100 km southwest of Lake Gilltjarnen, shows that the low early-Holocene temperatures were associated with high lake-levels at 10 500–8500 cal. yr BP, whereas low lake-levels and dry conditions prevailed during the period of high temperatures at between 7500 and 5000 cal. yr BP, probably due to high summer evapotranspiration and lower precipitation. Copyright © 2006 John Wiley & Sons, Ltd.

We used high-resolution paleoecological records of environmental change to study the rate and magnitude of eutrophication over the last century in two contrasting coastal ecosystems. A multiproxy approach using geochemical and biological indicators and diatom-based transfer functions provides a long-term perspective on changes in nutrient concentrations and the corresponding biological and sedimentary responses. In Roskilde Fjord, Denmark, total nitrogen (TN) increased 85% during the last century, with the most rapid increase occurring after the 1950s, corresponding to the postwar increase in N fertilizer use. In Laajalahti Bay, an urban embayment near Helsinki, Finland, total dissolved nitrogen (TDN) increased with growing wastewater inputs and decreased with the remedial actions taken to reduce these discharges. These changes are small relative to the order of magnitude increases in nutrient loading that have occurred in northwestern Europe, where the dissolved inorganic nitrogen (DIN) load has increased more than threefold in certain areas.

Pither & Aarssen (2005) propose a null model approach to assess the proportion of niche specialist taxa along ecological gradients. They apply this methodology to a large data set of lacustrine diatom assemblages and conclude that a majority of the taxa are generalists on a pH gradient. This conflicts with previous work, which shows that many diatom taxa have a statistically significant relationship with pH. We demonstrate the methods used by Pither & Aarssen (2005) have a high Type II error for rare taxa, and that this problem is compounded by the non-uniform sampling of the pH gradient which effectively precludes acid-lake specialist diatoms from being recognized as such. We re-analyse the data used by Pither & Aarssen (2005) and show that most of the diatoms have a statistically significant relationship with pH, and we thus refute their conclusions that few diatom species are specialists.