Lowland rainforest response to hydrological changes during the last 1500 years in Gabon, Western Equatorial Africa

Pollen and δ13CTOM data obtained from two contrasting lake sequences (Lakes Kamalété and Nguène), located 200 km apart in the lowland rainforest of Gabon, provide complementary local and regional 1500-yr records of high resolution (15–30 yr) vegetation change. A combination of aquatic, semi-aquatic and terrestrial pollen showed in both records that the tropical rainforest increased during periods of high rainfall and decreased during drought intervals. The strong fluctuations of water balance at decadal scale during the “Medieval Warm Period” (∼ 1100–800 cal yr BP) coincided with a noticeable increase in shade-intolerant taxa, indicating recurring rainforest canopy disturbance. The δ13CTOM signal showed high-amplitude variations in both records, which positively correlates with the rainforest dynamics and local vegetation changes. The similar trends in both the pollen and the δ13CTOM signals between these sites demonstrate the regional broadly synchronous timing of shifting hydrological conditions. The largely positive co-variation between strong fluctuations of hydrological conditions and changes in rainforest structure and composition indicate that regional climatic change is probably the driving force for major rainforest dynamics in Gabon. Any significant anthropogenic impact on vegetation has not been clearly identified, and this issue still needs to be resolved independently by obtaining detailed archeological records across the interval 1400–800 BP, which currently seem to be extremely rare or not easily available.

Orphaned and Endangered Collections in Invertebrate Paleontology: A Call for a National Solution

WITHIN BIOLOGY, the consummate synthetic, big-picture science is systematics and the fundamental resource and tool for systematics is natural history collections. Without systematics there is no unifying theme to the study of biology. Without natural history collections there is no systematics. Society and the institutions that house natural history collections must rediscover the value of those collections. These collections are a world treasure, a cultural heritage, an intellectual trust, a societal and institutional responsibility.Paleontology and paleontological collections contribute uniquely to the sciences of systematics and ecology. They provide the record of change through geological time evidence of the changes in the characteristics of species, changes in ecological associations of biota, and a record of abiotic global and regional climatic change. The study of this historical record allows the identification of the locations of certain sets of conditions from the past, illuminates our understanding of the present, and enables our prediction of future changes on a global scale.

PHENOLOGICAL RESPONSES OF PLANTS TO THERMAL GRADIENTS

Controversy over regional climatic change (RCC) and the direction of RCC continues. Models that predict how local plants would respond to defined regional climatic warming (RCW) would be useful. The urban heat island intensity (UHII) has been documented in a number of cities including Houston, Texas, Phoenix, Arizona, St. Louis, Missouri, and Gainesville, Florida. We studies the phenological response of selected horticultural plants growing along urban/rural thermal gradients in several cities where the UHII had previously been defined. Deciduous plants flowered earlier in the spring and retained their leaves longer in the fall in warmer urban areas than they did in adjacent rural areas. The phenological response of local plants to known thermal gradients appears to be a useful model of the phenological effects of potential RCW.