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The scarcity of long-term observational data has limited the use of statistical or machine-learning techniques for predicting intraannual ecological variation. However, time-stamped citizen-science observation records, supported by media data such as photographs, are increasingly available. In the present article, we present a novel framework based on the concept of relative phenological niche, using machine-learning algorithms to model observation records as a temporal sample of environmental conditions in which the represented ecological phenomenon occurs. Our approach accurately predicts the temporal dynamics of ecological events across large geographical scales and is robust to temporal bias in recording effort. These results highlight the vast potential of citizen-science observation data to predict ecological phenomena across space, including in near real time. The framework is also easily applicable for ecologists and practitioners already using machine-learning and statistics-based predictive approaches. [ABSTRACT FROM AUTHOR]

Quercus faginea (Portuguese oak) is a marcescent White Oak that is distributed across the western Mediterranean Basin in transitional sub-Mediterranean areas that include most of the western Portuguese coast. Due to land-use changes, its presence has been drastically reduced but there are still old-growth oaks, remnants of the native forest, that should be classified as deserving national legal protection for their cultural and aesthetic value as well as for their ecological importance. Much remains to be done in order to identify the trees to be protected and to increase social awareness of the importance of these secular oaks. Hopefully, the implementation of tailored management practices will encourage owners to protect these iconic trees. This work presents some of the oaks in western and central Portugal that have already been classified and others that should be. Our intention is that it serve to promote the future conservation of all old-growth oaks of patrimonial and ecological interest. [ABSTRACT FROM AUTHOR]

Marcescent forests are ecotones distributed across southern Europe that host increased levels of biodiversity but their persistence is threatened by global change. Here we study the range dynamics of these forests in the Iberian Peninsula (IP) during the Late Quaternary, a period of profound climate and anthropic changes. We modeled and compared the distribution of eight oak taxa for the present and two paleoclimatic environments, the Last Glacial Maximum (LGM, ~ 21 kya) and the Mid-Holocene (MH, ~ 6 kya). Presence records were combined with bioclimatic and topographic data in an ensemble modelling framework to obtain spatial projections for present and past conditions across taxa. Substantial distribution shifts were projected between the three studied periods, that were explained by precipitation, winter cold and terrain ruggedness. Results were congruent with paleoclimatic records of the IP and showed that range shifts of these contact zones concurred with range dynamics of both Submediterranean and Temperate oaks. Notably, the distribution ranges of hybrid oaks and marcescent forests matched throughout the late Quaternary. This study contributes to unveil the complex Late-Quaternary biogeography of the ecotone belt occupied by marcescent forests and, more broadly, of Mediterranean oaks. Improved knowledge of species' responses to climate dynamics will allow us to anticipate and manage future range shifts driven by climate change. [ABSTRACT FROM AUTHOR]

Aim: Fossil pollen is an important tool for understanding biogeographical patterns in the past, but the taxonomic resolution of the fossil‐pollen record may be limited to genus or even family level. Chemical analysis of pollen grains has the potential to increase the taxonomic resolution of pollen analysis, but present‐day chemical variability is poorly understood. This study aims to investigate whether a phylogenetic signal is present in the chemical variations of Quercus L. pollen and to assess the prospects of chemical techniques for identification in biogeographical research. Location: Portugal. Taxon: Six taxa (five species, one subspecies) of Quercus L., Q. faginea, Q. robur, Q. robur ssp. estremadurensis, Q. coccifera, Q. rotundifolia and Q. suber belonging to three sections: Cerris, Ilex and Quercus (Denk, Grimm, Manos, Deng, & Hipp, 2017). Methods: We collected pollen samples from 297 individual Quercus trees across a 4° (~450 km) latitudinal gradient and determined chemical differences using Fourier‐transform infrared spectroscopy (FTIR). We used canonical powered partial least squares regression (CPPLS) and discriminant analysis to describe within‐ and between‐species chemical variability. Results: We find clear differences in the FTIR spectra from Quercus pollen at the section level (Cerris: ~98%; Ilex: ~100%; Quercus: ~97%). Successful discrimination is based on spectral signals related to lipids and sporopollenins. However, discrimination of species within individual Quercus sections is more challenging: overall, species recall is ~76% and species misidentifications within sections lie between 18% and 31% of the test set. Main Conclusions: Our results demonstrate that subgenus level differentiation of Quercus pollen is possible using FTIR methods, with successful classification at the section level. This indicates that operator‐independent FTIR approaches can surpass traditional morphological techniques using light microscopy. Our results have implications both for providing new insights into past colonization pathways of Quercus, and likewise for forecasting future responses to climate change. However, before FTIR techniques can be applied more broadly across palaeoecology and biogeography, our results also highlight a number of research challenges that still need to be addressed, including developing sporopollenin‐specific taxonomic discriminators and determining a more complete understanding of the effects of environmental variation on pollen‐chemical signatures in Quercus. [ABSTRACT FROM AUTHOR]

Mediterranean forests are unique and one of the most threatened biomes worldwide (Klausmeyer and Shaw 2009). They are distributed through marked ecological gradients that are supported by a wide variety of diverse geology and contrasting bioclimatic conditions. Marcescence (i.e., the abscence of leaf fall abscission; Addicott 1982), is a life-history trait related to contrasting or transitional climatic areas such as those across Eurosiberian and Mediterranean Regions (García-Mijangos et al. 2014). Thus, marcescent forests are ecotones located in the transition between temperate areas with cold winters and mild rainy summers and mediterranean regions with dry and hot summers (Rivas-Martínez et al. 2017). We aim to provide a global overview of marcescent forests in the Mediterranean basin, a significant ecotone in terms of biogeography and conservation, by exploring the main ecological drivers that have promoted past, current and future changes in the distribution ranges of several oak species. We used a subset of oak species from the subsection Galliferae (Quercus L.), to unveil biogeographic relationships and recent or past contact between taxa, thus bringing insights to its evolutionary history and speciation. A database was built with records obtained from extensive fieldwork, herbaria review and online resources (e.g., Global Biodiversity Information Facility (GBIF), scrutinized by taxonomic experts. We used downscaled climate data to obtain potential distribution of each species through an ensemble-modelling framework (biomod2 - R package, Araújo and New 2007, Thuiller et al. 2009), across different past (Last Glacial Maximum and Middle Holocene), present and future scenarios (2050 and 2080 Hijmans et al. 2005; Representative Concentration Pathway (RCP) 4.5 IPCC 2013). Results provide new insights to advance our current understanding of the biogeographic trajectories of transiently co-occurring oak species, at the boundary of two major biomes and biogeographic regions in Southern Europe and North Africa. Furthermore, we highlight the importance of these forests for biodiversity conservation, not only as refuge of relict and narrow endemic species, but particularly for understanding white oak biogeography and evolution in Europe, anticipating future shifts driven by anthropogenic climate change. [ABSTRACT FROM AUTHOR]

Simple Summary: The ant-like flies are a group of nine species of flightless Tachydromia, with their distribution restricted to the Iberian Peninsula. Severe knowledge gaps regarding their distribution and ecological requirements hinder conservation assessments. To improve this scenario, an ensemble of 9 different species distribution models was applied to unveil habitat suitability and to provide guidelines for future studies. The most important factors influencing habitat suitability are climate-related, followed by forest type and structure, with well-defined biogeographic gradients. T. lusitanica and T. ebejeri are adapted to the mild temperature and high-humidity environments, typical of the Temperate–Eurosiberian life zone. T. semiaptera and T. iberica are adapted to progressively drier and hotter central and southern parts of the Iberian Peninsula, connected to transitional Temperate–submediterranean areas. Ant-like flies' distribution overlaps with deciduous/ marcescent oak species, which can effectively indicate their presence in Iberia. Additionally, southern marcescent forests emerge as "islands" with particular interest for future fieldwork. Ant-like flies are threatened by several factors such as climate change and habitat destruction, including urbanization and forest fires. This study provides vital tools to better assess the ant-like flies' conservation status and to manage their habitat. Ant-like flies comprise nine Iberian endemic species of flightless Tachydromia. Severe knowledge gaps on distribution and ecological requirements hinder conservation assessments. Species distribution models were applied to unveil habitat suitability and to provide guidelines for future studies. An ensemble modeling approach combining ten different techniques was implemented with the biomod2 package. Occurrence data was partitioned into six sets, including two multi-species groups and four species. The most relevant drivers of habitat suitability are climate-related, followed by forest type and structure, according to well-defined biogeographic gradients. T. lusitanica and T. ebejeri are adapted to mild temperatures and high-humidity environments. Their distribution is connected to the Temperate–Eurosiberian life zone. T. semiaptera and T. iberica are adapted to progressively drier and hotter central and southern parts of the Iberian Peninsula, connected to transitional Temperate–submediterranean areas. Ant-like fly' ranges overlap with deciduous/marcescent oak species, acting as suitable indicators of their presence in Iberia. Southern marcescent forests emerge as "islands" with particular interest for future prospections. Ant-like flies are threatened by several factors such as climate change and habitat destruction, including urbanization and forest fires. This study provides vital tools to better assess the ant-like flies' conservation status and to manage their habitat. [ABSTRACT FROM AUTHOR]

The Iberian Peninsula hosts a high diversity of oak species, being a hot-spot for the conservation of European White Oaks (Quercus) due to their environmental heterogeneity and its critical role as a phylogeographic refugium. Identifying and ranking the drivers that shape the distribution of White Oaks in Iberia requires that environmental variables operating at distinct scales are considered. These include climate, but also ecosystem functioning attributes (EFAs) related to energy–matter exchanges that characterize land cover types under various environmental settings, at finer scales. Here, we used satellite-based EFAs and climate variables in species distribution models (SDMs) to assess how variables related to ecosystem functioning improve our understanding of current distributions and the identification of suitable areas for White Oak species in Iberia. We developed consensus ensemble SDMs targeting a set of thirteen oaks, including both narrow endemic and widespread taxa. Models combining EFAs and climate variables obtained a higher performance and predictive ability (true-skill statistic (TSS): 0.88, sensitivity: 99.6, specificity: 96.3), in comparison to the climate-only models (TSS: 0.86, sens.: 96.1, spec.: 90.3) and EFA-only models (TSS: 0.73, sens.: 91.2, spec.: 82.1). Overall, narrow endemic species obtained higher predictive performance using combined models (TSS: 0.96, sens.: 99.6, spec.: 96.3) in comparison to widespread oaks (TSS: 0.80, sens.: 92.6, spec.: 87.7). The Iberian White Oaks show a high dependence on precipitation and the inter-quartile range of Normalized Difference Water Index (NDWI) (i.e., seasonal water availability) which appears to be the most important EFA variable. Spatial projections of climate–EFA combined models contribute to identify the major diversity hotspots for White Oaks in Iberia, holding higher values of cumulative habitat suitability and species richness. We discuss the implications of these findings for guiding the long-term conservation of Iberian White Oaks and provide spatially explicit geospatial information about each oak species (or set of species) relevant for developing biogeographic conservation frameworks. [ABSTRACT FROM AUTHOR]