Fagus grandifolia var. mexicana (Mexican beech) is limited to about 10 populations (2-35 ha) in the Sierra Madre Oriental, Mexico. The objectives were to assess the current status and distribution of beech by surveying five sites. Species richness varied between three to 27 tree species in the canopy, and from nine to 29 species in the understorey. Basal area of trees greater than or equal to 5 cm dbh varied between 27.87 and 70.98 m2 ha-1, and density from 370 to 1290 individual ha-1. Beech represented 22-99.6 of total basal area, and 6.8-83.3 of total density. Beech dominance varied from monodominant to codominance with Carpinus caroliniana, Quercus spp., Liquidambar styraciflua, Magnolia schiedeana, and Podocarpus spp. Beech total population size ranged from 180 to 6300 trees with a total of less than 1300 individuals in four sites. Anthropogenic disturbance remains a major threat to these forests. It is uncertain whether Mexican beech will be able to survive without conservation efforts.Resource Type: Journal Papers
The effects of Pleistocene glaciations on the genetic characteristics of the most austral conifer in the world, Pilgerodendron uviferum, were analysed with specific reference to the hypothesis that the species persisted locally in ice-free areas in temperate South America.
Results indicated that Pilgerodendron populations are highly monomorphic, probably reflecting past population bottlenecks and reduced gene flow. Southernmost populations tend to be the least genetically variable and were therefore probably more affected by glacial activity than northern ones. Populations located outside ice limits seem to have been isolated during the glacial period. The presence of centres of genetic diversity, together with the lack of a significant correlation between genetic and geographical distances and the absence of geographical patterns of allelic frequencies at most analysed alleles, may indicate that Pilgerodendron did not advance southward after the last glaciation from a unique northern refugium, but spread from several surviving populations in ice-free areas in Patagonia instead.Resource Type: Journal Papers
Araucaria araucana (Monkey Puzzle), a southern South American tree species of exceptional cultural and economic importance, is of conservation concern owing to extensive historical clearance and current human pressures. Random amplified polymorphic DNA (RAPD) markers were used to characterise genetic heterogeneity within and among 13 populations of this species from throughout its natural range.
Although populations are geographically divided into Chilean Coastal, Chilean Andes and Argentinean regions, this grouping explained only 1.77 of the total variation. Within Andean groups there was evidence of a trend of genetic distance with increasing latitude, and clustering of populations across the Andes, suggesting postglacial migration routes from multiple refugia. Implications of these results for the conservation and use of the genetic resource of this species are discussed.Resource Type: Journal Papers
Aquilaria spp. (Thymelaeaceae) are the principal source of Gaharu, a valuable resin, yet information about their reproductive ecology is almost entirely lacking. Individuals of six species (A. beccariana, A. crasna, A. filaria, A. hirta, A. malaccensis and A. microcarpa) in cultivation in Indonesia were investigated to assess reproductive phenology, pollination, seed production and germination. Seed production and seedling dispersion were also assessed in natural populations of A. beccariana, A. malaccensis and A. microcarpa in Kalimantan.
The results indicate that Aquilaria spp. have high reproductive potential, but suggest that seed dispersal might be limited in natural forests. The implications of these results for the management of Aquilaria spp. are discussed.Resource Type: Journal Papers
Spoon-billed Sandpiper Eurynorhynchus pygmeus is classed as globally Vulnerable, based on the only available population estimate, made in 1977, of 2,000-2,800 pairs. Surveys for breeding Spoon-billed Sandpipers were carried out in summer 2000 on the Anadyr estuary coast, the Chukotka autonomous region, Russia. Although six new breeding sites were found, only 16-17 breeding males/pairs were recorded on the northern coast of the Anadyr estuary and five males/pairs on the southern coast and more southerly lagoons. These numbers were much lower than expected, and the species was not recorded in several apparently suitable areas.Resource Type: Journal Papers
The International Waterbird Census (I WC), coordinated by Wetlands International, provides a framework for monitoring non-breeding populations at a global scale. However, wader counts are not yet available from most countries for enough years to allow meaningful population trend analyses. Nevertheless there is considerable potential for trend analyses using IWC data in the future. Many other studies use different and uncoordinated methods. We still lack facilities for broad-scale analyses which would allow the reasons for observed changes in wader populations to be explored. A GIS referenced, decentralised, web-based database interface is proposed which would help explain these changes by linking wader m onitoring initiatives, and by providing integration with other environmental monitoring schemes.Resource Type: Journal Papers
Recent analyses confirm that urgent attempts to catalogue the distribution of biological diversity may be facilitated by focusing at the level of genera or families rather than species. However, questions remain over the application of higher-taxon surveys to identify networks of priority areas for conservation action. Is the close spatial match between species and higher-taxon richness at global and regional scales reiterated when sites are locally distributed? How much money is saved by the higher-taxon approach? And how does using genus or family information affect the efficiency with which spatial priorities for conservation are identified? We examined these issues using data on the diversity of woody plants in Sri Lankan forests.Resource Type: Journal Papers
Aquilaria malaccensis (Thymelaeaceae) is the principal source of gaharu, one of the most valuable tropical forest products in international trade. Despite its economic importance, the autecology of this species is virtually unknown. Seedling growth and survival of A. malaccensis was monitored over a 15-month period in natural forest in West Kalimantan. Mean height growth rate was 21.2 + 2.3 cm year1, and was positively related to light availability (i^= 0.79, p < 0.001), but unrelated to distance to the nearest mature tree or seedling density. By the end of the observation period, fewer than 20% of seedlings surveyed initially were still alive, trampling and cutting being one of the main causes of mortality. A nursery experiment examined the influence of soil (two treatments), light availability (four treatments) and seedling density (four treatments) on growth. Although a decrease in irradiance was associated with significantly (p < 0.01, t - test) lower values for height and stem diameter, seedlings were able to survive under the low light treatment. Lower height growth rates and leaf increment were observed with higher seedling densities on the more fertile soil; no such effects of density were observed on the relatively infertile soil. The implications of these results for the sustainable management of A. malaccensis are discussed.Resource Type: Journal Papers
In the first of two papers, we explored congruence between species and higher-taxon richness across protected areas in Indo-Malaya and the Pacific rim. Our results support the use of the higher-taxon approach in guiding tropical conservation, but with certain reservations. In all three groups examined, higher-taxon richness was quite closely related to species number. However, the precision with which absolute species richness of reserves could be predicted from higher-taxon richness was often surprisingly low, particularly for rich sites where surveying higher taxa rather than species would save most time. The performance of higher taxa as surrogates also dropped sharply with increasing taxonomic rank, resulting in a trade-off between time saved by high-level surveys and the value of those surveys. Lastly, we found that species richness within individual higher taxa was potentially as powerful an indicator of the overall species diversity of a site as the number of higher taxa it contained.Resource Type: Journal Papers
Aquilaria spp. are the main source of gaharu, one of the most valuable non-timber products harvested from tropical forests. In order to assess the impact of gaharu harvesting on populations of Aquilaria spp. in Indonesia, the activities of gaharu collectors were assessed by accompanying them on collecting expeditions.
Given current harvesting practices, it is unlikely that gaharu is being sustainably harvested at present. The results suggest that the gaharu trade may have had a substantial impact on the population size of Aquilaria spp. in Indonesia, and their implications are discussed in the context of setting harvest quotas for regulation of trade, as required by CITES.Resource Type: Journal Papers
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