Olrik D.C.,Nature Agency |
Hauser T.P.,Copenhagen University |
Kjaer E.D.,Copenhagen University
Scandinavian Journal of Forest Research | Year: 2012
We quantified seed flow distances from seed trees of Quercus robur L. into areas with no forest cover based on a population of 147 trees growing next to an open heath land hosting many young oak seedlings. We sampled seedlings along four transects (6-700 m from the source population), and revealed likely parentage of seedlings by microsatellite genotyping data. We found seedlings that fitted the source population at distances up to 700 m, which was the furthest distance from the source population at which seedlings were sampled. However, we estimated that approximately half of the sampled seedlings did not originate from the source population, but must have been recruited from more distant oak populations, growing at least 500 m away. We conclude that the genetic origin and composition of natural regeneration of Q. robur are likely to originate from trees distributed at the landscape level rather than merely trees in the vicinity of the regenerated area. Implications for genetic management are discussed. The quantitative results fit well with qualitative reports of birds transporting acorns several hundred metres away from seed parents. © 2012 Copyright Taylor and Francis Group, LLC. Source
Hoffmann C.C.,University of Aarhus |
Heiberg L.,University of Southern Denmark |
Audet J.,University of Aarhus |
Schonfeldt B.,University of Southern Denmark |
And 7 more authors.
Ecological Engineering | Year: 2012
Re-established riparian wetlands used to mitigate nitrogen (N) loss from agricultural soils to surface water may lose phosphorus (P) from the top soils that often have received fertilizers. This could lead to eutrophication of lakes and estuaries. For a 2-year period we established mass balances of N and P in two restored riparian wetlands of ~0.6ha situated on mineral soil. Monitoring began 5 years after restoration. Both wetlands received drainage water from upland agricultural fields rich in nitrate (1.5-12.3mgNL -1) and low in total P (TP) (0.016-0.04mgPL -1). Water balances were reasonably accounted for (15% imbalance at most). Water passed the wetlands as sheet flow without exchange with groundwater because of clay horizons in sub-soils, and sheet pilings along the stream banks allowed continuous measurements of inflow and outflow. The Egeskov riparian wetland (wetland:upland ratio 0.13) removed 121 and 28kgNha -1yr -1 (43 and 75% of the load) and retained 0.08kgPha -1 (6% of the load) in year one and had a net release of 0.15kgPha -1 (25% of the load) in year two. The Stor å riparian wetland (wetland:upland ratio 0.02) removed 229 and 158kgNha -1yr -1 (32 and 26%). Net releases of P were 0.33 and 0.90kgPha -1yr -1 (22 and 127%). Nitrogen removal rates are on par with published rates for similar wetlands, while the P release rates appear surprisingly low. Phosphate outlet concentrations resembled the equilibrium concentrations (EPC 0) where no phosphate exchange occurred between top soils and drainage water, suggesting that P release or retention was controlled by phosphate adsorption. This value was 0.015mgPL -1 for Egeskov and 0.047mgPL -1 for Stor å. The high phosphate affinity was probably governed by high ratios between oxidized iron and iron-bound P. The top soils (10cm) contained 87 and 201kgPha -1 as iron-bound P and herbaceous vegetation accumulated 10.7 and 16.5kgPha -1yr -1. These figures are 55-136 and 8-11 times higher than the annual P-load to the wetlands, and we suggest that annual harvest of vegetation could maintain or even improve the P retention capacity of these wetlands. © 2012 Elsevier B.V.. Source
Schueler S.,Federal Research and Training Center for Forests |
Falk W.,Bavarian State Institute of Forestry |
Koskela J.,Third University of Rome |
Lefevre F.,French National Institute for Agricultural Research |
And 5 more authors.
Global Change Biology | Year: 2014
A transnational network of genetic conservation units for forest trees was recently documented in Europe aiming at the conservation of evolutionary processes and the adaptive potential of natural or man-made tree populations. In this study, we quantified the vulnerability of individual conservation units and the whole network to climate change using climate favourability models and the estimated velocity of climate change. Compared to the overall climate niche of the analysed target species populations at the warm and dry end of the species niche are underrepresented in the network. However, by 2100, target species in 33-65 % of conservation units, mostly located in southern Europe, will be at the limit or outside the species' current climatic niche as demonstrated by favourabilities below required model sensitivities of 95%. The highest average decrease in favourabilities throughout the network can be expected for coniferous trees although they are mainly occurring within units in mountainous landscapes for which we estimated lower velocities of change. Generally, the species-specific estimates of favourabilities showed only low correlations to the velocity of climate change in individual units, indicating that both vulnerability measures should be considered for climate risk analysis. The variation in favourabilities among target species within the same conservation units is expected to increase with climate change and will likely require a prioritization among co-occurring species. The present results suggest that there is a strong need to intensify monitoring efforts and to develop additional conservation measures for populations in the most vulnerable units. Also, our results call for continued transnational actions for genetic conservation of European forest trees, including the establishment of dynamic conservation populations outside the current species distribution ranges within European assisted migration schemes. © 2013 John Wiley & Sons Ltd. Source
Ramos E.,University of Cantabria |
Juanes J.A.,University of Cantabria |
Galvan C.,University of Cantabria |
Neto J.M.,University of Coimbra |
And 13 more authors.
Estuarine, Coastal and Shelf Science | Year: 2012
According to requirements for intercalibration of assessment methods of vegetation quality elements along the North East Atlantic region, within the scope of the European Water Framework Directive (WFD), a better classification system of coastal regions is needed. To accomplish that goal, a quantitative classification approach was launched in order to establish common typologies for assessment of this biological quality element. This was preliminarily based on a physical classification of the coastal waters that included two consecutive steps, a first one devoted to the establishment of "biotypes" (large areas), and a latter one dealing with recognition of the variability within biotypes (" subtypological variants"). The NEA region coastline was subdivided into 550 consecutive stretches (40 km long). Then, physical variables (sea surface temperature, photosynthetically active radiation, wave exposure, tidal range and salinity) were calculated in reference points of each stretch, 5. km from the coast. This information was based mostly on satellite acquired data, using specific procedures proposed in this work. Physical typologies of NEA coastal waters were obtained by statistical analyses. Five different biotypes were selected (i.e. coastal sectors of the European coast) by national experts as baseline information to be used on intercalibration of assessment methods for vegetation within the WFD. Variability of environmental conditions on those biotypes was also analyzed and compared with previous classifications carried out at the national scale. Results from this study showed the feasibility of this methodological approach as a useful tool for assessment of the actual homogeneity of coastal environments. © 2011 Elsevier Ltd. Source
Lefevre F.,French National Institute for Agricultural Research |
Koskela J.,Third University of Rome |
Hubert J.,Japan Forestry and Forest Products Research Institute |
Kraigher H.,Slovenian Forestry Institute |
And 36 more authors.
Conservation Biology | Year: 2013
Dynamic conservation of forest genetic resources (FGR) means maintaining the genetic diversity of trees within an evolutionary process and allowing generation turnover in the forest. We assessed the network of forests areas managed for the dynamic conservation of FGR (conservation units) across Europe (33 countries). On the basis of information available in the European Information System on FGR (EUFGIS Portal), species distribution maps, and environmental stratification of the continent, we developed ecogeographic indicators, a marginality index, and demographic indicators to assess and monitor forest conservation efforts. The pan-European network has 1967 conservation units, 2737 populations of target trees, and 86 species of target trees. We detected a poor coincidence between FGR conservation and other biodiversity conservation objectives within this network. We identified 2 complementary strategies: a species-oriented strategy in which national conservation networks are specifically designed for key target species and a site-oriented strategy in which multiple-target units include so-called secondary species conserved within a few sites. The network is highly unbalanced in terms of species representation, and 7 key target species are conserved in 60% of the conservation units. We performed specific gap analyses for 11 tree species, including assessment of ecogeographic, demographic, and genetic criteria. For each species, we identified gaps, particularly in the marginal parts of their distribution range, and found multiple redundant conservation units in other areas. The Mediterranean forests and to a lesser extent the boreal forests are underrepresented. Monitoring the conservation efficiency of each unit remains challenging; however, <2% of the conserved populations seem to be at risk of extinction. On the basis of our results, we recommend combining species-oriented and site-oriented strategies. © 2012 Society for Conservation Biology. Source