Drought, fire and grazing precursors to large-scale pine forest decline

Aim Temperate forests are currently facing multiple stresses due to climate change, biological invasions, habitat fragmentation and fire regime change. How these stressors interact with each other influences how, when and whether ecosystems recover, or whether they adapt or transition to a different ecological state. Because forest recovery or collapse may take longer than a human lifetime, predicting the outcomes of different stressor combinations remains difficult. A clearer vision of future forest trajectories in a changing world may be gained by examining collapses of forests in the past. Here, we use long-term ecological data to conduct a post-mortem examination of the decline of maritime pine forests (Pinus pinaster Ait.) on the SW Iberian Peninsula 7000-6500 years ago. Location Portugal and Spain. Methods We compared four palaeoecological records-two with pine declines and two without-using a multiproxy approach. Bioclimatic differences between the four sites were explored. Proxies for past vegetation and disturbance (fire and grazing) were compared with independent palaeoclimatic records. We performed functional traits analysis and used phase plots to examine the causes of pine decline. Results The pine decline represents a critical transition in SW Iberia, which lies close to maritime pine's bioclimatic limits. Prolonged drought likely killed trees and suppressed the fires that normally stimulate pine germination and pinewood recovery. Increased grazing pressure facilitated the rapid spread of resprouter shrubs. These competed with pine trees and ultimately replaced them. Our data highlight complex interactions between climate, fire, grazing and forest resilience. Main Conclusions The pine decline occurred at least a century after post-fire resprouters overtook obligate seeders in the vegetation, constituting an early-warning signal of forest loss. Fire suppression, resprouter encroachment and grazing may threaten the persistence of Mediterranean forests as droughts become more frequent and extreme.PTDC/AAC--CLI/108518/2008info:eu-repo/semantics/publishedVersio

Household Food Insecurity and Nutrition Status: Implications for Child's Survival in South-Western Nigeria

This study investigated the relationship between household food insecurity and nutrition status with a focus on the implications for child survival. Data were collected on 746 women of child-bearing age (15 - 49 years) in five states in south western Nigeria. The study finds that household food security increased with income and education. The findings show that child survival is not only about improving nutrition status in the household or improving household food security, but also activities that mothers undertake to enhance child survival

Tertiary Institutions and Development in Rural Communities: Role of Federal University Oye-Ekiti, Ekiti State, Nigeria

This paper examines the economic impact of Federal University Oye-Ekiti, Ekiti State, Nigeria on its host communities in Oye and Ikole towns since inception. The study sets out with a major objective of determining whether the establishment of the university would organically lead to the development of its host communities. Quantitative and qualitative techniques were adopted for research design while the stratified sampling technique was used in administering the questionnaire for the study. The results show that while the establishment of tertiary institutions has a potential to increase household income in rural communities where they are located, it does not necessarily lead to the development of these communities in terms of basic health care facilities, primary education centers, good road networks and improved standard of living

Pollen and plant diversity relationships in a Mediterranean montane area

Understanding the significance of pollen diversity is key to reconstructing plant diversity over long timescales. Here we present quantitative pollen-plant diversity comparisons for a mountainous area of the Western Mediterranean region. Samples were collected between 430–1,865 m elevation and pollen-plant diversity assessed through richness and turnover (beta-diversity) metrics. We found statistically significant relationships between pollen diversity metrics and the diversity of pollen-equivalent plant taxa in the surrounding vegetation. The strongest richness relationships emerged from the exclusion of trees and with standardisation of the sample size (rarefaction) applied to both plant and pollen datasets. Three different metrics for turnover produced similar results, but emphasise different components of beta diversity (replacement vs richness differences). These results pave the way for reconstructing biodiversity trends from pollen sequences, with a number of caveats. Fossil pollen is a potentially rich source of information on past biodiversity in the Mediterranean region