Thunen Institute For Waldokosysteme
Thunen Institute For Waldokosysteme
Seidling W.,Thunen Institute For Waldokosysteme |
Kanold A.,Landesanstalt fur Wald und Forstwirtschaft LWF |
Kompa T.,Johannisstr. 8 |
Lambertz B.,Ohrshauser Str. 3 |
And 6 more authors.
Tuexenia | Year: 2014
Local species richness is a crucial biodiversity measure also in monitoring projects. This study was carried out in a species-rich beech forest on limestone within the communal forest of the city of Göttin-gen. It compares species richness estimates from nine surveyors (five individuals and two teams of two) on plots of 4, 100, and 400 m2 size. The influence of surveyor and elapsed time on the outcome was investigated. Additionally, species-specific overlooking and misinterpretation rates were estimated. As a further source of error, wrong assignment of plant specimen to plots was considered. Analysis of recorded questions of the probates did not reveal a differentiated familiarity with the on-site vegetation on the base of their professional embedding in regional terms. Outcomes have therefore to be seen as the result of individual training and experience. On the spatial level of the 4 m2 plots relative deviances between expected values of species richness and estimates of individual surveyors varied between 8 and 26% (1 to 4 species absolutely). At the 100 m2 plots differences between survey-ors were with 9 to 27% (2 to 6 species absolutely) even more pronounced. With increasing plot area effects from plot identity tend to decrease, while observer effects distinctly increase. For the 100 m2 plot level an effect of processing time was detectable. None of the species were found by all surveyors at all subplots on which they occurred. Closely re-lated or otherwise similar species, and those which were in an unfavourable developmental stage, had a higher chance of being overlooked or misinterpreted. Species with peculiar morphological features were considered to be misallocated. For all three types of error respective rates were calculated. The relationships found have generally to be considered in monitoring projects focusing on vegeta-tion changes; however, in large-scale cross-sectional surveys respective error rates should be consid-ered. An organized controlling system is outlined.
Tipping E.,UK Center for Ecology and Hydrology |
Benham S.,Japan Forestry and Forest Products Research Institute |
Boyle J.F.,University of Liverpool |
Crow P.,Japan Forestry and Forest Products Research Institute |
And 11 more authors.
Environmental Sciences: Processes and Impacts | Year: 2014
We compiled published and newly-obtained data on the directly-measured atmospheric deposition of total phosphorus (TP), filtered total phosphorus (FTP), and inorganic phosphorus (PO4-P) to open land, lakes, and marine coasts. The resulting global data base includes data for c. 250 sites, covering the period 1954 to 2012. Most (82%) of the measurement locations are in Europe and North America, with 44 in Africa, Asia, Oceania, and South-Central America. The deposition rates are log-normally distributed, and for the whole data set the geometric mean deposition rates are 0.027, 0.019 and 0.14 g m -2 a-1 for TP, FTP and PO4-P respectively. At smaller scales there is little systematic spatial variation, except for high deposition rates at some sites in Germany, likely due to local agricultural sources. In cases for which PO4-P was determined as well as one of the other forms of P, strong parallels between logarithmic values were found. Based on the directly-measured deposition rates to land, and published estimates of P deposition to the oceans, we estimate a total annual transfer of P to and from the atmosphere of 3.7 Tg. However, much of the phosphorus in larger particles (principally primary biological aerosol particles) is probably redeposited near to its origin, so that long-range transport, important for tropical forests, large areas of peatland and the oceans, mainly involves fine dust from deserts and soils, as described by the simulations of Mahowald et al. (Global Biogeochemical Cycles 22, GB4026, 2008). We suggest that local release to the atmosphere and subsequent deposition bring about a pseudo-diffusive redistribution of P in the landscape, with P-poor ecosystems, for example ombrotrophic peatlands and oligotrophic lakes, gaining at the expense of P-rich ones. Simple calculations suggest that atmospheric transport could bring about significant local redistribution of P among terrestrial ecosystems. Although most atmospherically transported P is natural in origin, local transfers from fertilised farmland to P-poor ecosystems may be significant, and this requires further research. This journal is © the Partner Organisations 2014.
Neubauer M.,Thunen Institute For Waldokosysteme |
Demant B.,Thunen Institute For Waldokosysteme |
Bolte A.,Thunen Institute For Waldokosysteme
Forstarchiv | Year: 2015
The greenhouse gas reporting for forests in Germany according to the rules of the Kyoto Protocol requires determining the'. carbon stock change of sustainable forest management. Therefore also root biomass data is needed, which can be derived from tree or stand traits above ground with high accuracy. So far, the root biomass was estimated based on basic relations between above and below ground biomass according to the Intergovernmental Panel on Climate Change (IPCC). To verify these values, the above- and the belowground biomass of 43 Scots pines (Pinus sylvestris L) in the age between 15 to 220 years were analyzed in plots near to Eberswalde (Brandenburg/Germany). For analyses the pines were pulled down with a winch. Then the roots were weighted and the aboveground biomass was measured. With these dates allometric functions could be derived, which describe the relationship between diameter at breast height (DBH) or tree volume and root biomass that can be used for biomass assessments below ground. The synopsis with other allometric functions taken from literature showed partly large deviations of predicted values probably due to variation of sampling method, but also different climate and site conditions as well as different sampled tree dimensions. These findings suggest the use of regional assessment functions. Comparing tree-related with stand-related assessments, a significant overestimation of root biomass is evident when using the stand-related assessments according to the IPCC without tree species differentiation. © DLV GmbH.