Showing papers by "Adrian C. Newton published in 2007"

Forest Ecology and Conservation: A Handbook of Techniques

Abstract: 1. Introduction 2. Forest Extent and Condition 3. Forest Structure and Composition 4. Understanding Forest Dynamics 5. Modelling Forest Dynamics 6. Reproductive Ecology and Genetic Variation 7. Forest as Habitat 8. Towards Effective Forest Conservation

Impacts of forest fragmentation on species composition and forest structure in the temperate landscape of southern Chile

Abstract: Aim Few studies have explicitly examined the influence of spatial attributes of forest fragments when examining the impacts of fragmentation on woody species. The aim of this study was to assess the diverse impacts of fragmentation on forest habitats by integrating landscape-level and species-level approaches. Location The investigation was undertaken in temperate rain forests located in southern Chile. This ecosystem is characterized by high endemism and by intensive recent changes in land use. Method Measures of diversity, richness, species composition, forest structure and anthropogenic disturbances were related to spatial attributes of the landscape (size, shape, connectivity, isolation and interior forest area) of forest fragments using generalized linear models. A total of 63 sampling plots distributed in 51 forest fragments with different spatial attributes were sampled. Results Patch size was the most important attribute influencing different measures of species composition, stand structure and anthropogenic disturbances. The abundance of tree and shrub species associated with interior and edge habitats was significantly related to variation in patch size. Basal area, a measure of forest structure, significantly declined with decreasing patch size, suggesting that fragmentation is affecting successional processes in the remaining forests. Small patches also displayed a greater number of stumps, animal trails and cow pats, and lower values of canopy cover as a result of selective logging and livestock grazing in relatively accessible fragments. However, tree richness and β-diversity of tree species were not significantly related to fragmentation. Main conclusions This study demonstrates that progressive fragmentation by logging and clearance is associated with dramatic changes in the structure and composition of the temperate forests in southern Chile. If this fragmentation process continues, the ability of the remnant forests to maintain their original biodiversity and ecological processes will be significantly reduced.

Resistance, epidemiology and sustainable management of Rhynchosporium secalis populations on barley

Abstract: Rhynchosporium secalis is one of the most destructive pathogens of barley worldwide, causing yield decreases of up to 40% and reduced grain quality. Rhynchosporium is a polycyclic disease. Primary inoculum includes conidia produced on crop debris, infected seeds and possibly ascospores, although these have not yet been identified. Secondary disease spread is primarily by splash dispersal of conidia produced on infected leaves, which may be symptomless early in the growing season. Host resistance to R. secalis is mediated by both 'major' or host-specific genes (complete resistance) and 'minor' genes of smaller, generally additive effects (partial resistance). Crop growth stage and plant or canopy architecture can modify the expression of resistance. Resistance genes are distributed unevenly across the barley genome, with most being clustered on the short arms of chromosomes 1H, 3H, 6H and 7H, or in the centromeric region or on the long arm of chromosome 3H. Strategies used to manage rhynchosporium epidemics include cultivar resistance and fungicides, and also cultural practices such as crop rotation, cultivar mixtures and manipulation of sowing date, sowing rate or fertiliser rate. However, the high genetic variability of R. secalis can result in rapid adaptation of pathogen populations to render some of these control strategies ineffective when they are used alone. Sustainable control of rhynchosporium needs to integrate major-gene-mediated resistance, partial resistance and other strategies such as customized fungicide programmes, species or cultivar rotation, resistance gene deployment, clean seed and cultivar mixtures.

The Red List of Magnoliaceae

Abstract: The Red List of the Magnoliaceae, published jointly by Botanic Gardens Conservation International (BGCI) and Fauna & Flora International (FFI), through the Global Trees Campaign (GTC), identifies 131 wild magnolias as being in danger of extinction, from a global total of 245 species.

Biodiversity Loss and Conservation in Fragmented Forest Landscapes: The Forests of Montane Mexico and Temperate South America

Abstract: Spatial and temporal patterns of forest loss and fragmentation in Mexico and Chile Plant diversity in highly fragmented forest landscapes in Mexico and Chile: implications for conservation Fragmentation and edge effects on plant-animal interactions, ecological processes and biodiversity Habitat fragmentation and reproductive ecology of Embothrium coccineum, Eucryphia cordifolia and Aextoxicon punctatum in southern temperate rain forests Patterns of genetic variation in tree species and their implications for conservation Secondary succession under a slash-and-burn regime in a tropical montane cloud forest: soil and vegetation characteristics. The impact of logging and secondary succession on the below-ground system of a cloud forest in Mexico Applying succession models to the conservation of tropical montane forest Models of regional and local stand composition and dynamics of pine-oak forests in the Central Highlands of Chiapas (Mexico): theoretical and management implications Process-based modelling of regeneration dynamics and sustainable use in species-rich rain forests Testing forest biodiversity indicators by assessing anthropogenic impacts along disturbance gradients Fire challenges to conserving tropical ecosystems: the case study of Chiapas Identification of priority areas for conservation in South Central Chile Restoration of forest ecosystems in fragmented landscapes of temperate and montane tropical Latin America Future scenarios for tropical montane and south temperate forest biodiversity in Latin America.

Effects of varying forest edge permeability on seed dispersal in a neotropical montane forest

Abstract: Hard (high-contrast with pastures) and soft (low-contrast with old-fields) forest edges created by slash-and-burn agriculture have become common landscape features in regions dominated by neotropical montane forest. However, little is know about the impacts of such edge types on forest regeneration dynamics. The consequences of varying forest edge permeability for oak acorn dispersal were investigated in a forest mosaic in the Highlands of Chiapas, Mexico. Rates of acorn production and removal, as well as the abundance and composition of small mammal seed consumers, were monitored along these different edge types (hard vs. soft) at specific distances from forest edges into forest patches and adjacent grasslands during two consecutive years. Results show that acorn removal declined significantly only in grasslands of sites characterised by hard edges (Logistic regression, P < 0.05). Movements of metal-tagged acorns support the hypothesis that soft edges are more permeable to small mammals, with rodents moving acorns up to 15 m into grasslands of sites with soft edges. In sites with hard edges, higher rates of acorn dispersal were recorded from the forest edge towards the forest interior. Peromyscus spp. were the main acorn predators and/or dispersers of acorns present in our study sites. Rates of acorn removal during a non-masting year were greater than the subsequent mast-seeding year (85% removal within 138 days vs. 75% within 213 days), demonstrating that mast seeding may allow some seeds to escape predation. The implications of these results for oak dispersal and regeneration along edges in fragmented tropical forest landscapes are discussed.

Restoration of Forest Ecosystems in Fragmented Landscapes of Temperate and Montane Tropical Latin America

Abstract: Temperate and tropical montane forests in Latin America represent a major natural resource at both regional and national levels for a number of reasons - biological, climatic, economic, cultural. Native tree species in these forests share conservation problems because of deforestation, habitat degradation, overall biodiversity loss and integrity of landscape structure. However, literature on forest restoration research and practices in these ecosystems is scanty and dispersed. We integrate forest restoration experiences aimed at a variety of purposes that allow us to gain insight over several years under contrasting ecological, social and economic conditions in six study regions: the Argentinian Andes, the IX and X Regions in Chile (including northern Chiloe Island), and central Veracruz and the central and northern Highlands of Chiapas (Mexico). By comparing analogous conditions and highlighting differences among the study sites, current pitfalls can be identified and used to define a minimum set of elements to be considered in a protocol for restoration practices. The restoration studies reviewed here include a wide variety of ecological and socio-economic circumstances that allow the identification of broad guidelines, criteria and indicators for planning, implementing and monitoring ecological restoration programmes. We conclude with statements that suggest approaches, strategies and concrete actions that might be considered as lessons learned and inputs for best practice in forest restoration research and programmes conducted in other developing regions.

Patterns of genetic variation in tree species and their implications for conservation.

Abstract: Increasing concern surrounding the loss of natural forests and the decline in biodiversity has lead to a rise in research and policy initiatives in recent years However, interest has focused primarily on lowland tropical rainforests Tropical montane and temperate rainforests, which face similar pressures from human activities and play major roles in the livelihood of rural communities, are often ignored Biodiversity Loss and Conservation in Fragmented Forest Landscapes is the product of over ten years of intensive field research into the changing montane and temperate rainforests of Mexico and South America By concentrating on these largely overlooked environments, the studies reported allow for comparative analysis across areas and help identify how human disturbance has impacted the biodiversity of all forest types Chapters incorporate features of landscape ecology, floristic biodiversity, conservation and policy and vary from in-depth investigations of a single study area to integrated examinations across regions

Scale does matter

Abstract: Current woodland conservation policy stresses the importance to preserve, expand and re-connect habitat fragments on a landscape scale. However, Dolman and Fuller (2003) suggest that more studies are necessary on woodland specialists species to provide a firmer basis for current management strategies. To address this knowledge gap, research was undertaken on a specialist woodland invertebrate, the wood cricket (Nemobius sylvestris) on the Isle of Wight, UK. In 2005, a landscape scale survey and in 2006 a more detailed study within 3 separate woodland fragments was undertaken. The results of both studies were used to assess the relevance of a landscape scale approach for conservation effort of this species.

Identification of Priority Areas for Conservation in South-central Chile

Abstract: Increasing concern surrounding the loss of natural forests and the decline in biodiversity has lead to a rise in research and policy initiatives in recent years. However, interest has focused primarily on lowland tropical rainforests. Tropical montane and temperate rainforests, which face similar pressures from human activities and play major roles in the livelihood of rural communities, are often ignored. Biodiversity Loss and Conservation in Fragmented Forest Landscapes is the product of over ten years of intensive field research into the changing montane and temperate rainforests of Mexico and South America. By concentrating on these largely overlooked environments, the studies reported allow for comparative analysis across areas and help identify how human disturbance has impacted the biodiversity of all forest types. Chapters incorporate features of landscape ecology, floristic biodiversity, conservation and policy and vary from in-depth investigations of a single study area to integrated examinations across regions.

Testing the ecological principles of forest landscape restoration

Abstract: In recent decades, human activities have increasingly fragmented native forest habitat in many parts of the world. This is associated with ongoing loss of natural habitat, which is increasingly recognised as the main cause of biodiversity loss (Fahrig, 2003). In several countries, conservation policy now stresses the need to preserve, expand and re-connect habitat fragments at a landscape scale to reverse the continuous loss of species. In the United Kingdom, woodland conservation is focussing on efforts to reduce and reverse current fragmentation and habitat loss (Peterken, 2002). This has resulted in several policy initiatives focussing on the concept of creating Forest Habitat Networks (FHN) (e.g. Humphrey et al., 2005). These initiatives focus on new woodland development towards linking existing woodland fragments together (Peterken, 2002; Humphrey et al., 2005). This approach is based on the belief that creating new native woodland on suitable locations reduces the negative effects of habitat fragmentation on woodland biodiversity by providing links and ‘stepping stones’ between isolated populations of woodland species (e.g. Spellerberg and Gaywood, 1993). Dolman and Fuller (2003) suggest that more studies are necessary on woodland specialists species to provide a firmer basis for current management strategies. To address this knowledge gap, research was undertaken on a specialist woodland invertebrate, the wood cricket (Nemobius sylvestris) on the Isle of Wight, UK. Wood cricket is associated with native broadleaved woodlands as its preferred habitat (Richards, 1952) and is of local conservation concern. The main objective was to determine the landscape scale distribution of this species in order to assess whether patch- and landscape-scale variables are related to its occurrence. The results of this study were used to critically examine the principles underpinning woodland restoration and evaluate current forest policy.