Dionysia mira (Jaub. & Spach.) Wendelbo is endemic to the northern mountains of Oman, where it is restricted to a few isolated populations in the eastern and western Hajar Mountains; the extent of ...populations has not been accurately documented. Here we investigate the population size and distribution, habitat preferences, reproductive biology and potential threats, and ex‐situ conservation initiatives at Oman Botanic Garden are discussed. In 2017, 4045 flowering plants were recorded; of which 3595 were concentrated around the village of Shnoot on Jabal Al Akhdar in the western Hajar mountains. Plants are found between 1700 m and 2500 m a.s.l. on north facing limestone gravel slopes and fissures on vertical outcrops and cliff faces within Sideroxylon mascatense – Olea europaea and Teucrium mascatense – Juniperus seravschanica vegetation communities. Plant density within the core population at Shnoot is 52 plants/100 m2; 46% of which were mature plants, 32% semi‐mature and 15% seedlings. The mean number of seeds per plant was 14 000; bee‐flies (Bombyliidae) are suggested as likely pollinators. Using freshly collected seeds under controlled conditions between 10°C and 30°C a 90% germination rate was recorded; there was no difference in the germination rates between stratified and non‐stratified seeds. Dionysia mira is under threat from predicted climate change scenarios in the region and habitat loss through widespread development within its core range. Long‐term ex‐situ conservation programme at Oman Botanic Garden maintains a seed and living plant collection.
The data presented in this article are related to the research article “Inter-annual variation in species composition and richness after coppicing in a restored coppice-with-standards forest” ...(Strubelt et al., 2019). The underlying data of that research article are presented here: Monitoring of the vascular plant species composition of 12 permanent plots analysed every year from 1994 till 2002 and again in 2013. For the 2013 survey, data about environmental variables also exist and are included in this data article. The dates of coppicing were recorded for all of these plots, which enabled us to analyse the dynamics of species richness and composition after coppicing on a year to year basis in the above-stated research data article.
Agri-environmental subsidies for grasslands of high conservation interest are usually associated with fairly strict management rules, but have not always been successful in terms of the preservation ...of species. A new approach now links the subsidies paid to the ecological value of a grassland site: the farmers are paid for keeping up a high plant species richness, and they can control the species richness of their sites by using vascular plants as indicator species. The method was tested in different grassland communities in six regions of Lower Saxony in Northwestern Germany, mainly addressing the question whether the number of selected indicator species was correlated with the total species richness of vascular plants and with the number of endangered species.
Field work was carried out in 2004. Total species richness of vascular plants was recorded in all grassland sites, and the number of indicators was counted along two transects, usually being the diagonals of a rectangular site. Each transect was divided into three segments in which all indicators growing within 1
m distance from the transect line were recorded. In total 43 indicators were selected, mostly representing species that are fairly easy to recognise.
The number of indicators was significantly positively correlated with the total number of species in all regions, also when correcting for autocorrelation (except in one region). When using grassland area as a co-variable, the same results were obtained, supporting the low significance of grassland size for the predictive ability of the method. In all regions but one, the mean number of indicators per segment was also significantly positively related to the number of red-listed and near-threatened species in the grasslands. Grassland size and transect length were found to be of minor importance for the application of the method.
In conclusion, the study shows that the indicator approach is suitable for identifying those grassland sites that have a high plant species richness and a high number of endangered species. It may thus form the basis for result-orientated subsidies in grasslands.
The aquatic macrophyte Stratiotes aloides L. is of conservation concern in central Europe due to its high importance for biodiversity in lowland floodplain and ditch ecosystems. However, over the ...last decades this species has shown population declines for instance in Germany or the Netherlands. S. aloides is dioecious with male and female individuals, in mixed or separated stands, often reproducing vegetatively. Generative reproduction is observed less frequently, but of great importance for declining plant populations facing threats of habitat destruction and eutrophication. Precisely which arthropods transfer S. aloides pollen was previously unknown. We examined flower visitors of S. aloides in the 2011 and 2014 flowering seasons in ditches of a wet grassland ecosystem in Bremen, Northwest Germany. Hydrellia tarsata Haliday (Diptera: Ephydridae) was found abundantly in male and female flowers of S. aloides in both years. Pollen of S. aloides was actively transferred by H. tarsata and reproduction of the fly in S. aloides leaves was detected by rearing H. tarsata from extracted puparia. The mining Hydrellia were parasitised by the braconid wasps Chaenusa “punctulata” Burghele and Chorebus “densepunctatus” Burghele, which also visited S. aloides flowers in 2011 and 2014. These results point to a mutualism between S. aloides and the ephydrid H. tarsata, with both partners benefiting with their own reproduction. This relationship between plant and dipteran pollinator is however complicated in a tritrophic interaction with the braconid parasitoids, which infest the mining stages of the ephydrid flies and could potentially also transfer S. aloides pollen.
•We carried out vegetation studies in the currently largest CWS project in Germany.•We analysed coppicing induced changes in vascular plant species richness.•CWS restoration led to an increase in ...species richness, particularly tree regeneration.•“Nitrogen time bomb” scenario after canopy opening did not happen in our study area.•True forest species are not negatively affected by coppicing.
Coppice-with-standards (CWS) management was one of the most important disturbances in Central European forests in the past. As our knowledge about the effects of coppicing on species richness and composition needs to be enhanced, we carried out vegetation studies in the currently largest CWS project in Germany. In this article we focus on two issues: 1. Coppicing induced changes and trends in species richness and composition from year to year and 2. Development of species richness and composition in 19 years of CWS restoration.
Salzgitter Höhenzug mountains between Liebenburg and Goslar, Lower Saxony, Germany. Climate: subatlantic to subcontinental; soil: Limestone rendzina with low water storage capacity.
In 2013 we resurveyed the plant species composition of 12 permanent plots analysed every year from 1994 till 2002. The dates of coppicing were recorded for all of these plots, which enabled us to analyse the dynamics of species richness and composition after coppicing on a year to year basis. Differences in species richness and composition were analysed using ANOVA, H-test, DCA and GLMM.
In 19 years of CWS restoration mean plot species richness increased significantly, mainly attributed to the increase in woody species, such as Quercus robur and Sorbus torminalis. The Ellenberg indicator value for nutrients decreased significantly, whereas the indicator value for light increased significantly. The typical dynamic after coppicing consists of a continuous increase in shrub layer coverage and an increase in herb layer coverage with a maximum in years 3 and 4 after coppicing. Total species richness as well as richness of open habitat and forest species and true forest species also showed an increase with its maximum in years 3 and 4 after coppicing.
Our results showed that the alternation of light and shaded phases had a positive impact on species richness, particularly on tree regeneration. Considering the trend of decreasing species richness level in Central European forests, CWS forests play a major role in the conservation of vascular plant species diversity. In contrast to other studies, the increase in species richness after coppicing did not result from an increase in weedy, nitrogen-demanding species. The so called “nitrogen time bomb” scenario (which other authors assumed to be happening after opening the canopy) did not occur in the studied area. The low water storage capacity of the limestone rendzina soil may be one reason, as there was not sufficient water and nitrogen for the more demanding species.
Questions: (1) How has the species richness of an alluvial forest changed over the past 52 yrs, and what are the main drivers of the observed temporal changes; (2) has the species composition changed ...over this period in response to changes in environmental variables; and (3) what are the main drivers of species richness (change) in this forest? Location: Haseder Holz, Innerste floodplain in lowland northern Germany. Methods: In 2012 we resurveyed the plant species composition of 19 permanent plots analysed for the first time in 1960 and for a second time in 2002. At the most recent survey, several environmental variables (photosynthetically active radiation, soil water content, groundwater table, pH and content of soil P, Ca, Mg, K, C and N) were measured in five locations within each plot. GLM were used to examine the relationship between explanatory variables and species richness, while variation in species composition, in time and space, was assessed by DCA. Results: The number of species generally increased with decreasing soil nutrient (except Mg) content, with increasing variation in light availability and with increasing variation in content. The significant increase in species richness from 1960 to 2012 was mainly attributed to the increase in true forest species, such as Paris quadrifolia and Mercurialis perennis, and woody species. The most pronounced increase in species richness was found in plots with lower soil phosphate content. Species typical for open habitats showed the most pronounced decrease from 1960 to 2012. A significant homogenization of the plots over time was observed. Conclusions: Against the common trend in European forests, we found a significant increase in mean species richness, especially in plots with relatively low nutrient content. While the total pool of species has not consistently increased, we found a strong increase in plot-scale species richness of woody and herbaceous species. This overall increase and the slight decrease in the proportion of species typical of open habitats were probably driven by a decrease in light availability caused by less intensive management. Our results demonstrate that finescale spatial environmental heterogeneity positively affects species richness. In contrast to recently reported findings, we found a decrease in the number of species with increasing nutrient content.
•We carried out vegetation studies in the ancient oak forest Hasbruch in Germany.•We analysed drivers of changes in vascular plant species richness.•We analysed the effect of management and ...vegetation type on these changes.•The main drivers for changes in species richness were light and water availability.•Effects of the drivers strongly depended on the vegetation type.
We carried out vegetation studies in the ancient Hasbruch forest, which provided the unique conditions of unmanaged (UM) and managed (M) stands in two vegetation types Stellario-Carpinetum loniceretosum (POOR) and stachyetosum (RICH) stands in one closed forest allowing us to study (1) the changes in species composition and richness over 20 years considering the entire forest as well as (2) group-specific changes.
Hasbruch forest in the lowlands of Lower Saxony, Germany.
In 2016 we resurveyed the vascular plant species composition of 79 semi-permanent plots analysed in 1996. General and group-specific trends as well as drivers of changes were analysed using DCA, PCA, LM, t-test, U test, ANOVA.
Tree and shrub layer coverage increased significantly in the entire forest. Herb layer species richness decreased significantly only in group RICH_UM. While the pH-value increased significantly in group POOR, it decreased significantly in group B. EIV F increased significantly in group POOR_M and decreased significantly in group RICH_UM. EIV L increased significantly in both of the managed groups, while it decreased significantly in group RICH_UM. An increase was found for EIV N in group POOR_M, whereas a decrease was found in group RICH_M. Strongly increasing species were Ilex aquifolium, Rubus fruticosus agg. and Hedera helix; strongly decreasing species Geum urbanum and Primula elatior. The change in species richness was positively affected by ΔpH and negatively affected by ΔT1cov in the entire forest.
The main drivers for changes in species richness and composition in the Hasbruch forest were light and water availability. The effects of the drivers strongly depended on the vegetation type. Changes in species composition were more pronounced in nutrient-rich forests than on nutrient-poor sites. In nutrient-rich forests, decreased groundwater influence led to decreased soil pH which especially affected typical woodland plants in a negative way. Management positively affected light-demanding species as well as some N-demanding species. Thus, unmanaged, nutrient-rich stands displayed the highest losses in species diversity. In the nutrient-poor stands, changes in species composition were not significantly related to changes in soil and management. However, increasing pH as well as increased Ellenberg L, F, and N values suggest a tendency towards eutrophication. This is possibly a consequence of N deposition and recovery from soil acidification.
Questions (1) How has the species richness of an alluvial forest changed over the past 52 yrs, and what are the main drivers of the observed temporal changes; (2) has the species composition changed ...over this period in response to changes in environmental variables; and (3) what are the main drivers of species richness (change) in this forest? Location Haseder Holz, Innerste floodplain in lowland northern Germany. Methods In 2012 we resurveyed the plant species composition of 19 permanent plots analysed for the first time in 1960 and for a second time in 2002. At the most recent survey, several environmental variables (photosynthetically active radiation, soil water content, groundwater table, pH and content of soil P, Ca, Mg, K, C and N) were measured in five locations within each plot. GLM were used to examine the relationship between explanatory variables and species richness, while variation in species composition, in time and space, was assessed by DCA. Results The number of species generally increased with decreasing soil nutrient (except Mg) content, with increasing variation in light availability and with increasing variation in K content. The significant increase in species richness from 1960 to 2012 was mainly attributed to the increase in true forest species, such as Paris quadrifolia and Mercurialis perennis, and woody species. The most pronounced increase in species richness was found in plots with lower soil phosphate content. Species typical for open habitats showed the most pronounced decrease from 1960 to 2012. A significant homogenization of the plots over time was observed. Conclusions Against the common trend in European forests, we found a significant increase in mean species richness, especially in plots with relatively low nutrient content. While the total pool of species has not consistently increased, we found a strong increase in plot-scale species richness of woody and herbaceous species. This overall increase and the slight decrease in the proportion of species typical of open habitats were probably driven by a decrease in light availability caused by less intensive management. Our results demonstrate that fine-scale spatial environmental heterogeneity positively affects species richness. In contrast to recently reported findings, we found a decrease in the number of species with increasing nutrient content.
An indicator species approach for result-oriented subsidies of ecological service in grasslands is presented. A new approach links the subsidies paid to the ecological value of a grassland site: the ...farmers are paid for keeping up a high plant species richness, and they can control the species richness of their sites using vascular plants as indicator species. The method is tested in difference grassland communities in six regions of Lower Saxony in Northwestern Germany, mainly addressing the question whether of vascular plants and with the number of endangered species. Each transect is divided into three segments in which all indicators growing within 1 m distance from the transect line are recorded. In total 43 indicators are selected, mostly representing species that are fairly easy to recognize.
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