The history of Erica erigena R. Ross,an Irish plant with a disjunct European distribution

Scanning electron microscopy combined with pollen, spore, rhizopod and fungal analyses of two peat profiles at Claggan Mountain, Co. Mayo, sheds new light on the Holocene history of Erica erigena in western Ireland. This heather is referred to the Mediterranean-Atlantic group in the Irish flora, and is remarkable for its disjunct distribution in Europe, where it occurs in Ireland, Bordeaux in France, and in Spain and Portugal. Scanning electron microscopy has proved a powerful tool, allowing the unambiguous identification of ericoid pollens to species level and it is used to identify the first occurrence of Erica erigena pollen in the peat profiles. Radiocarbon dating of the profiles shows that Erica erigena is a relatively recent arrival at Claggan Mountain, appearing for the first time in the historic period at 1431 AD. The details of vegetational changes associated with the expansion of E. erigena have been explored by conventional pollen, spore, rhizopod and fungal analyses. Drying of the peat surface and replacement of bog vegetation by ericaceous heathland during a period of marked agricultural activity in the region was associated with its spread. The relatively recent arrival of E. erigena at Claggan Mountain, suggests that introduction might explain its presence here, and its disjunct distribution in Europe. Documented trade and pilgrimage routes between Ireland and those areas in Europe where the heather occurs may have allowed its recent introduction into Ireland. Further pollen analysis work, using SEM techniques, will be required if an earlier occurrence for the heather in Ireland is to be proved. The combination of techniques described here may prove useful in the study of the history of other plants with pollen that is difficult to identify using conventional light microscopy.     

Plantation Forestry in Tropical Limestone Uplands: Environmental Constraints and Opportunities

This study addresses anthropogenic and ecological factors affecting a 50 hectare farmer-managed reforestation project in the cone karst of the central Philippine island of Bohol. Climate, soil moisture, micro-topographic features, soil fertility, management practices, and pre-plantation land use history are all related to, and assist in explaining the variability in, gmelina and mahogany survival and growth rates. Pre-plantation land use affects soil fertility and structure (affecting moisture-holding capacity), and micro-geomorphologic features such as slope angle, slope length, breaks in slope, and size and distribution of talus influenced tree growth and survival rates because of their relationship to soil erosion and deposition.     

Cloud water interception in the high altitude tree heath forest (Erica arborea L.) of Paul da Serra Massif (Madeira,Portugal)

Cloud water interception (CWI) occurs when cloud droplets are blown against the forest canopy, where they are retained on the vegetation surface, forming larger water droplets that drip into the forest floor. CWI was measured from 1 October 1997 to 30 September 1999, on a first‐line tree heath (Erica arborea), at Bica da Cana, Madeira Island. Rainfall was corrected for wind‐loss effect and compared with throughfall and other climatological normals. The CWI depletion rate along a forest stand transect was also analysed during three distinct fog events in 2008. Cloud water was 28 mm day^?1, corresponding to 68% of total throughfall and 190% of the gross precipitation. Cloud water correlates directly with monthly normals of fog days and wind speed and correlates inversely with the monthly air temperature normal. CWI has an exponential correlation with monthly relative humidity normal. Cloud water capture depletion along the stand shows a logarithmic decrease. Although a forest stand does not directly relate to a first‐line tree heath, this study shows that CWI is a frequent phenomenon in the Paul da Serra massif. Restoration and protection of high altitude ecosystems in Madeira should be a priority, not only for biodiversity, ecological and economical purposes but also for its role in regional water resources. Copyright © 2011 John Wiley & Sons, Ltd.