The Late Oxfordian ammonite faunas of the semimammatum and semiarmatum biohorizons are described, mostly based on material from the Impressamergel Formation of the Plettenberg Quarry near ...Dotternhausen (western Swabian Alb). 21 ammonite are recorded, including some previously undescribed from the Upper Jurassic of SW Germany. Previously, the semimammatum Biohorizon has been studied in Franconia, Western France and central Poland and the semiarmatum Biohorizon only in Western France, respectively. Compared to the semimammatum Biohorizon, the semiarmatum Biohorizon is characterized by a significant increase of Submediterranean and Tethyan taxa and a total decline of Subboreal ones. This phenomenon is interpreted as the result of a seawater warming trend towards the above following bimammatum Biohorizon, which correlates with the recently suggested Oxfordian/Kimmeridgian stage boundary. This article summarizes the current state of knowledge of the Hypselum Zone in SW Germany. A lectotype is designated for Richeiceras lochense (Oppel, 1863).
Submediterranean forests are considered an ecotone between Mediterranean and Eurosiberian ecosystems, and are very sensitive to global change. A decline of Scots pine (Pinus sylvestris L.) and a ...related expansion of oak species (Quercus spp.) have been reported in the Spanish Pre-Pyrenees. Although this has been associated with increasing drought stress, the underlying mechanisms are not fully understood, and suitable monitoring protocols are lacking. The aim of this study is to bring insight into the physiological mechanisms anticipating selective decline of the pines, with particular focus on carbon and water relations. For this purpose, we performed a sampling campaign covering two growing seasons in a mixed stand of P. sylvestris and Quercus subpyrenaica E.H del Villar. We sampled seasonally twig xylem and soil for water isotope composition (δ18O and δ2H), leaves for carbon isotope composition (δ13C) and stems to quantify non-structural carbohydrates (NSC) concentration, and measured water potential and leaf gas exchange. The first summer drought was severe for both species, reaching low predawn water potential (-2.2 MPa), very low stomatal conductance (12 ± 1.0 mmol m-2 s-1) and near-zero or even negative net photosynthesis, particularly in P. sylvestris (-0.6 ± 0.34 μmol m-2 s-1 in oaks, -1.3 ± 0.16 μmol m-2 s-1 in pines). Hence, the tighter stomatal control and more isohydric strategy of P. sylvestris resulted in larger limitations on carbon assimilation, and this was also reflected in carbon storage, showing twofold larger total NSC concentration in oaks than in pines (7.8 ± 2.4% and 4.0 ± 1.3%, respectively). We observed a faster recovery of predawn water potential after summer drought in Q. subpyrenaica than in P. sylvestris (-0.8 MPa and -1.1 MPa, respectively). As supported by the isotopic data, this was probably associated with a deeper and more reliable water supply in Q. subpyrenaica. In line with these short-term observations, we found a more pronounced negative effect of steadily increasing drought stress on long-term growth in pines compared with oaks. All these observations confer evidence of early warning of P. sylvestris decline and indicate the adaptive advantage of Q. subpyrenaica in the area.
Euonymus latifolius is a paradigmatic nemoral-subMediterranean species of the relict flora from Würmian glaciations in the Iberian Peninsula. Due to its transitional nature, taxa of this plant group ...could be used as a sensitive indicator to evaluate the effects of climate change on plants in the near future. In the Iberian Peninsula, E. latifolius is scattered in relict, isolated small populations, and catalogued as critically endangered. Previous studies of this taxon indicated the strong dependence of recruitment on canopy cover, which was attributed to the shade-meditated maintenance of soil humidity in the juvenile microhabitat. However, no information is available on the effects of light radiation on this nemoral species. In this study, we investigated the growth response of E. latifolius to photosynthetically active radiation by producing and transplanting saplings along a broad light intensity gradient, i.e., from direct illumination to dense shaded canopy, in a nemoral mixed deciduous forest stand in the Botanic Garden of Castilla-La Mancha. Our results confirmed the marked sciophilous nature of E. latifolius, which is particularly uncommon in the Mediterranean flora, by demonstrating a drastic reduction in growth with the increase of exposure to light intensity, which became critical at high values and even lethal when plants were directly exposed to light. The opening of the canopy in the natural habitat of this species due to simplification of the structure of nemoral communities promoted by climate change in southern latitudes of Europe comprises a real and short-term risk for E. latifolius, and probably for other relict nemoral-subMediterranean species. Conservation actions are recommended.
Mediterranean mountainous environments are biodiversity hotspots and priority areas in conservation agendas. Although they are fragile and threatened by forecasted global change scenarios, their ...sensitivity to long-term environmental variability is still understudied. The Sierra Nevada range, located in southern Spain on the north-western European flanks of the Mediterranean basin, is a biodiversity hotspot. Consequently, Sierra Nevada provides an excellent model system to apply a palaeoecological approach to detect vegetation changes, explore the drivers triggering those changes, and how vegetation changes link to the present landscape in such a paradigmatic mountain system. A multi-proxy strategy (magnetic susceptibility, grain size, loss-on-ignition, macroremains, charcoal and palynological analyses) is applied to an 8400-year long lacustrine environmental archive from the Laguna de la Mosca (2889 masl). The long-term ecological data show how the Early Holocene pine forests transitioned towards mixed Pinus-Quercus submediterranean forests as a response to a decrease in seasonality at ~7.3 cal. kyr BP. The mixed Pinus-Quercus submediterranean forests collapsed drastically giving way to open evergreen Quercus formations at ~4.2 cal. kyr BP after a well-known aridity crisis. Under the forecasted northward expansion of the Mediterranean area due to global change-related aridity increase, mountain forests inhabiting territories adjacent to the Mediterranean Region could experience analogous responses to those detected in the Sierra Nevada forests to the Mid to Late Holocene aridification, moving from temperate to submediterranean and then Mediterranean formations.
•8300 cal. BP to present high-altitude palaeoecological record from Sierra Nevada (SW Europe)•Biotic and abiotic proxies reconstruct environmental change and fire impact on a biodiversity hotspot•Holocene seasonality decrease and aridity increase shaped Sierra Nevada vegetation landscapes•Vegetation structure and its sensibility to fire are essential modulators of landscape change.•Projection of the data herein provided may predict future scenarios of environmental change
The present work proposes new boundaries for the current submediterranean territories of the Iberian Peninsula, defining them at the smallest scale attempted to date. The boundaries proposed are not ...sharp divisions but somewhat 'gradual', reflecting the transitional nature of the territories they encompass. Climate change predictions were used to estimate how the distribution of these submediterranean regions might change in the near future. The maps constructed are based on the distribution of marcescent Quercus species--trees that characterise the submediterranean plant landscape where they form the main forest communities. To determine their climatic range, the distribution of different types of Iberian oak forest was represented in 'climate diagrams' (ordination diagrams derived from principal components analysis), both in terms of individual species and groups of species based on leaf ecophysiological type, i.e. marcescent (Submediterranean), sclerophyllous (Mediterranean), semideciduous (Mediterranean) and deciduous (Eurosiberian). The climate range of each type of forest was determined, and the means of representative climate variables are analysed by one way ANOVA. The variables differentiating the forest groups were also examined by discriminant analysis. The range of the climate variables found to be associated with the majority of marcescent forests was used to determine the distribution of territories throughout the Peninsula with the same conditions (i.e. whether marcescent forests were present or not), thus providing a map of the Iberian submediterranean territories. Predictions of climate change were used to investigate possible climate-induced modifications in the boundaries of these territories in the near future. The patterns obtained show dramatic reductions in the extension of the Iberian submediterranean environment. Submediterranean conditions will probably disappear from the areas where they currently reign, and it seems unlikely that any new, large submediterranean areas will form by displacement towards higher altitudes. The outlook for the unique submediterranean vegetation of the Iberian Peninsula is gloomy.
“SIVIM Deciduous Forests” is a thematic database established in 2015, focused on forest vegetation from the Iberian Peninsula and southern France. It was registered in the Global Index of Vegetation ...Databases (GIVD ID: EU-00-023) in January 2016. All types of temperate and submediterranean non-riparian deciduous forests of the phytosociological classes
Carpino-Fagetea sylvaticae
,
Quercetea pubescentis
and
Quercetea robori-petraeae
(formerly combined in the class
Querco-Fagetea
) are represented in the database. Currently, it contains 6,642 published vegetation plots of beech, birch, ash, lime and other deciduous mixed forests, as well as forests dominated by different species of deciduous and marcescent oaks, 100% of them classified at association level. Data are stored in TURBOVEG format, and are available upon request from the international vegetation-plot databases EVA and sPlot in semi-restricted regime. The relevés have also been included in SIVIM database, and thus they are freely available online. However, in SIVIM Deciduous Forests geolocation accuracy has been improved and the taxonomy and syntaxonomy unified. Plot size is available for 73% of the relevés, of which 82% are between 100 and 400 m
2
. Plant taxonomy is standardized to Flora iberica. During the last four years, data of SIVIM Deciduous Forests were requested via EVA and sPlot for different projects, and have been used for several studies with various objectives, from floristic, vegetation and habitat-related topics to macroecological studies, and from local to global scales.
Abbreviations
: EVA = European Vegetation Archive; GIVD = Global Index of Vegetation-Plot Databases; SIVIM = Iberian and Macaronesian Vegetation Information System.
Forests in Submediterranean Slovenia are threatened by wildfires every year. The article presents the main characteristics of post-fire regeneration in the Karst area. The rate of succession was ...studied by comparing two burned sites with different periods after the last fire. Field plant sampling was used to determine the plant cover and species composition on each site. Vegetation characteristics were contrasted with nearby unburned sites. We found that the plant species composition of burned areas is similar to that of areas unaffected by wildfire, and that the monitored site has been colonised by specific pioneer plant species five years after the wildfire.
Bioclimatic transition zones are supposed to encompass sensitive areas to global change effects on forest ecosystems. In this study, we attempt to detect shifts in the ranges of contrasting Iberian ...tree species in the submediterranean transition zone in Navarra, northern Spain. These shifts are analysed in the context of a significant increase in temperature over recent decades along with moderate land use changes. Data from national forest inventories (1971 and 2010) are compared through universal kriging (UK) and block kriging models to assess the shifts in the ranges of
Quercus subpyrenaica
,
Quercus ilex
,
Pinus sylvestris
and
Fagus sylvatica
. UK results predicted an increase in the presence probability of the four target species for the whole Navarra region. However, in the submediterranean zone, the presence probability of
Q. subpyrenaica
,
P. sylvestris
and
F. sylvatica
shows a shrinking trend, whereas
Q. ilex
is expanding its range, supporting a previous hypothesis of a “mediterranization” of this bioclimatic transition region. These trends are concomitant with recent elevational shift patterns towards higher elevations in the case of
Q. subpyrenaica
,
P. sylvestris
and
F. sylvatica
in the transition zone. Moreover, the expected increase in species richness as a consequence of geographical shifts and vegetation recovery is identified. The moderate human influence detected in the study area confirms the major role of climate warming as driver of species range shifts over the period. The results of this study highlight the suitability of bioclimatic transition zones for monitoring the effects of global change on natural ecosystems, providing evidences of the complex mechanisms affecting the distribution of forests.
Due to the ongoing effects of climate change in the Mediterranean (increasing temperature and decreasing rainfall), conditions for Submediterranean species are disappearing as their habitats are ...dwindling. We have focused on Euonymus latifolius (L.) Mill., a nemoral-Submediterranean species, at its southernmost populations of Europe. The aim was to evaluate the population structure and regeneration niche of the species at microhabitat scale. We selected five larger populations among the 13 existing ones, marking 25-30 individuals per population. We measured twice: height, width, vegetation cover, survival, soil moisture and temperature. As result, we provided data of the 13 existing populations, containing 93 adults and 350 juveniles.
Moreover, we have obtained a very skew population structure with a low number of recruits for five selected populations, especially at smaller populations. Most E. latifolius juveniles were encountered under dense tree canopy (more than 80 % in cover) formed by a mixture of Submediterranean and Mediterranean species. Biovolume per population showed significant differences among the main populations CP and CV, presenting this last a higher recruitment, while recruitment was very low in general. For soil parameters, we found a critical role of canopy, which showed a positive effect on juvenile microhabitat (higher moisture and lower soil temperature).
The results showed us the critical situation of the species, with very fragmented populations, low number of individuals, and scattered spatial patterns of individuals within the populations. Also, survival problems, a non-balance demographic structure, and regeneration problems were detected. Finally, we propose a sere of conservation measures, from monitoring to active measures (key tree species plantation, reintroduction, reinforcements), combined with threat control (herbivory, pests, and impact from outdoor activities). All combined may help to preserve this species at its southernmost populations.
The importance of mountains for plant diversity and richness is underestimated, particularly when transition zones between different bioclimates are present along altitudinal gradients. Here we ...present the first floristic data for a mountain area in the island of Sardinia (Italy), which exhibits Mediterranean bioclimates at the bottom and temperate bioclimate at the top. We discovered a very high floristic richness, despite the fact that the number of endemic taxa is not high and the number of exclusive taxa is very low. Many of the detected taxa are at their range periphery and/or ecological margin. We conclude that climate transition zones in Mediterranean mountains and especially on islands are key areas regarding plant biodiversity and should be better investigated and protected.
PDF
