Long-Term Vegetation Change in Central Africa: The Need for an Integrated Management Framework for Forests and Savannas

peer reviewedTropical forests and savannas are the main biomes in sub-Saharan Africa, covering most of the continent. Collectively they offer important habitat for biodiversity and provide multiple ecosystem services. Considering their global importance and the multiple sustainability challenges they face in the era of the Anthropocene, this chapter undertakes a comprehensive analysis of the past, present, and future vegetation patterns in central African forests and savannas. Past changes in climate, vegetation, land use, and human activity have affected the distribution of forests and savannas across central Africa. Currently, forests form a continuous block across the wet and moist areas of central Africa, and are characterized by high tree cover (>90% tree cover). Savannas and woodlands have lower tree cover (<40% tree cover), are found in drier sites in the north and south of the region, and are maintained by frequent fires. Recent tree cover loss (2000–2015) has been more important for forests than for savannas, which, however, reportedly experienced woody encroachment. Future cropland expansion is expected to have a strong impact on savannas, while the extent of climatic impacts depends on the actual scenario. We finally identify some of the policy implications for restoring ecosystems, expanding protected areas, and designing sustainable ecosystem management approaches in the region

Angiosarcoma of the thyroid and concurrent hyperthyroidism.

We describe the exceptional association of an angiosarcoma of the thyroid and hyperthyroidism in a 74-year-old woman who presented with a toxic multinodular goiter of recent growth. This association reported in two other cases may not be fortuitous but due a vascular effect of the angiosarcoma contributing to the development of thyrotoxicosis. This case also illustrates the diagnostic difficulties and the poor prognosis of this tumor

Minor alterations in thyroid-function tests associated with diabetes mellitus and obesity in outpatients without known thyroid illness.

Thyroid function tests might be affected by diabetes and obesity. To evaluate the influence of these parameters in routine conditions, 72 diabetic and 53 non-diabetic outpatients without known thyroid diseases or severe chronic illness were recruited over a 7-month period. For each patient, dosages of thyrotropin (TSH), total and free thyroxine (TT4 and FT4, respectively), total and free triiodothyronine (TT3 and FT3) and T3 resin uptake (T3RU) were performed by radioimmunoassays. The simultaneous influence of various parameters known to affect thyroid-function tests was evaluated by multivariate linear regression. The studied variables included gender, age, glucosteroids, estrogens, tobacco habits, iodine contacts, body mass index (BMI) and diabetes mellitus. Tobacco habits and iodine contacts did not influence any tests. As expected, estrogens induced an increase in TT4 and TT3 values (p < 0.001 and 0.020, respectively) associated with a decrease in T3RU (p < 0.001). Consequently, females had lower T3RU than males (p < 0.0001). Corticotherapy was associated with decreased TSH values (p = 0.022). TT3 and FT3 decreased with age (p < 0.001), whereas T3RU and FT4 increased (p = 0.020 and 0.004, respectively). In contrast to an increase in TSH (p = 0.006), TT4 and FT4 decreased at higher BMI levels (p = 0.018 and 0.004, respectively), which is consistent with subclinical hypothyroidism. In diabetic patients, TSH was lower than in nondiabetic subjects (p = 0.039). Thus, the present study indicates that besides known parameters such as age and drugs, thyroid-function tests can also be altered by diabetes mellitus and obesity

Enjeux fonciers, exploitation des ressources naturelles et Forêts des Communautés Locales en périphérie de Kinshasa, RDC

Land issues, exploitation of natural resources, and Forests of Rural Communities in the periphery of Kinshasa, DRC. Peri-urban forests are under strong anthropic pressure. Any activity needs a previous identification of stakeholders, landscape perception, socio-economic trends in local communities and their relationships with land and natural resources. Kinshasa (capital of Democratic Republic of Congo, DRC) is a 10 millions inhabitants city with rapid growth and increasing impacts on surrounding villages linked with forest natural resources. This paper describes the relationship amongst local communities stakeholders and their relations with land areas and wood resources. Two areas surrounding Kinshasa (Bas-Congo and Bateke Plateaux) are considered as major fuel-wood and charcoal supply zones for the city. Those two areas are different in terms of land pressure (very high in Bas-Congo and focused on riparian forests on Bateke Plateaux), but show the same pattern of overuse of the forest and woody natural resources. In both areas, local management of forest resources by the traditional authorities (heads of village or lineage) has failed. Local population willingness for reforestation and forest restoration activities is much more important in Bas-Congo than on Bateke Plateaux. In both areas, shifting cultivation due to slash and burn practices for agricultural and charcoal practices are more and more quick. This has strong negative impact on the potential of regeneration process with local forest species. Sustainability of forest natural resources management by communities is discussed in regard to the on going negotiations on community based forest management regulations