Deep time: the emerging role of archaeology in landscape ecology

Given the goals of landscape ecology, information from archaeological sites provides a useful source of evidence regarding cultural practices, anthropogenic change, local conditions, and distributions of organisms at a variety of scales across both space and time. Due to the time depth available from the archaeological record, long-term processes can be studied and issues of land use legacies, human influence on landscape heterogeneity, and system histories can be addressed. Archaeological data can produce a diachronic record of past population size, population structure, biogeography, age-at-death, and migration patterns, useful for making ecosystem and wildlife management decisions. Researchers can use archaeological knowledge to differentiate between native and alien taxa, inform restoration plans, identify sustainable harvesting practices, account for modern distributions of taxa, predict future biogeographic changes, and elucidate the interplay of long- and short-term ecological processes.     

Life-table experiments with Helisoma duryi (Wetherby) and Biomphalaria Pfeifferi (Krauss) at constant temperatures

In an effort to find an ecological homologue that could be utilized as a biological control agent of the intermediate host species of economically important helminth parasites, age-specific life-table experiments with Helisoma duryi (Wetherby) ind Biomphalaria pfeifferi (Krauss) (intermediate host of Schistosoma mansoni) were carried out at a series of constant temperatures in a laboratory. The results showed that the lifespan and net reproduction rate of H. duryi were higher than those of B. pfeifferi over the whole range of temperatures investigated (18-35°C). The conclusion is reached that H. duryi should theoretically be capable of establishing viable populations in most of the habitats occupied by B. pfeifferi in South Africa.     

The effect of constant low temperatures on the survival of Bulinus africanus (Krauss), Bulinus globosus (Morelet) and Biomphalaria pfeifferi (Krauss)

The tolerance to low temperature of the freshwater snail species Bulinus africanus, Bulinus globosus and Biomphalaria pfeifferi was experimentally investigated. Snails were exposed to temperatures ranging from 0 °C to 8 °C and their survival was noted daily. The results showed that the survival of the cohorts of all three species decreased as the temperature was lowered in the range investigated. Evidence is presented which demonstrates that B. africanus can withstand cold conditions better than B. globosus, and that a globosus is better equipped than a pfeifferi in withstanding low water temperatures.     

Characterization of volatiles and aroma-active compounds in honeybush (Cyclopia subternata) by GC-MS and GC-O analysis

Volatile organic compounds (VOCs) in fermented honeybush, Cyclopia subternata, were sampled by means of a high-capacity headspace sample enrichment probe (SEP) and analyzed by gas chromatography-mass spectrometry (GC-MS). Stereochemistry was determined by means of enantioselective GC-MS with derivatized β-cyclodextrin columns as chiral selectors. A total of 183 compounds, the majority of which are terpenoids (103; 56%), were identified by comparing their mass spectra and retention indices with those of reference compounds or tentatively identified by comparison with spectral library or literature data. Of these compounds, 37 were determined by gas chromatography-olfactometry (GC-O), using detection frequency (DF) and aroma extract dilution analysis (AEDA), to be odor-active (FD ≥ 2). (E)-β-Damascenone, (R/S)-linalool, (E)-β-damascone, geraniol, (E)-β-ionone, and (7E)-megastigma-5,7,9-trien-4-one were identified with the highest FD factors (≥512). The odors of certain compounds, that is, (6E,8Z)-megastigma-4,6,8-trien-3-one, (6E,8E)-megastigma-4,6,8-trien-3-one, (7E)-megastigma-5,7,9-trien-4-one, 10-epi-γ-eudesmol, epi-α-muurolol, and epi-α-cadinol, were perceived by GC-O assessors as typically honeybush-like.     

Antioxidant activity and diffusion of catechin and epicatechin from antioxidant active films made of poly(L-lactic acid)

Active membranes and food packaging containing antioxidants like catechin and epicatechin, combined with the use of materials made of biopolymers obtained from renewable sources, could create a novel alternative to reduce oxidation in food, pharmaceutical, and cosmetic products. Poly(94% L-lactic acid) films containing 1.28% catechin and 1.50% epicatechin were extruded in a pilot plant-scale extrusion machine. The diffusion kinetics of catechin and epicatechin into 95% ethanol at 20, 30, 40, and 50 °C and 50% ethanol at 40 °C displayed Fickian release behavior and diffusion coefficients between 0.5 and 50 × 10(-11) cm(2)/s. According to the Arrhenius equation, the energy of activation for the diffusion of catechin and epicatechin in the films was 110.43 and 98.92 kJ/mol, respectively. The antioxidant activity of the films was measured in methanol extracts containing 46.42 μg/mL of catechin and 57.52 μg/mL of epicatechin as 32.90 and 36.68% of scavenging the 2,2-diphenyl-1-picrylhydrazyl radical, respectively.     

Genetic diversity and spatial structure in a new distinct <Emphasis Type="Italic">Theobroma cacao</Emphasis> L. population in Bolivia

Cacao (Theobroma cacao L.) is an important economic crop in the Bolivian Amazon. Bolivian farmers both cultivate cacao, and extract fruits from wild stands in the Beni River region and in valleys of the Andes foothills. The germplasm group traditionally used is presently referred to as “Cacao Nacional Boliviano” (CNB). Using DNA fingerprinting technology based on microsatellite markers, we genotyped 164 Bolivian cacao accessions, including both cultivated and wild CNB accessions sampled from the Amazonian regions of La Paz and Beni, and compared their SSR profiles with 78 reference Forastero accessions from Amazonian cacao populations, including germplasm from the Ucayali region of Peru. Results of multivariate ordination and analysis of molecular variance show that CNB cacao has a unique genetic profile that is significantly different from the known cacao germplasm groups in South America. The results also show that cultivated CNB and wild CNB populations in the Beni River share a similar genetic profile, suggesting that the cultivated CNB is of indigenous origin in Bolivia. The level of genetic diversity, measured by allele richness and gene diversity in the Bolivian cacao, is moderately high, but was significantly lower than gene diversity in the other Amazonian cacao populations. Significant spatial genetic structure was detected in the wild CNB population, using analysis of autocorrelation (rc = 0.232; P < 0.001) and Mantel tests (Rxy = 0.276; P < 0.001). This finding is also highly valuable to support in situ conservation and sustainable use of CNB genetic diversity in Bolivia.     

The effect of co‐composted cabbage and ground phosphate rock on the early growth and P uptake of oilseed rape and perennial ryegrass

Phosphorus (P) availability to crops in organic systems can be a major issue, with the use of readily available forms often restricted. One product that can be used in organically managed systems, that is also relatively easily accessible to growers, is phosphate rock, although its solubility and therefore crop availability is often poor. One possible approach to improve this situation is co‐composting phosphate rock with selected organic waste materials. Various ratios of phosphate rock and cabbage (Brassica oleracea L.) residues were co‐composted and the products tested at different rates of application. The effects were assessed over 12 weeks using oilseed rape (Brassica napus L.) and perennial ryegrass (Lolium perenne L.) as bioassay crops in a pot experiment. At harvest, estimates of P derived from cabbage and phosphate rock for the lowest of two rates of compost were ≈ 2 and 10 mg P pot^–1 for oilseed rape, compared to 5 and 2 mg P pot^–1 for perennial ryegrass, respectively. Roots tended to have higher P concentrations than shoots. The crops showed differences in their abilities to access various P sources, with oilseed rape effectively taking P from phosphate rock, whereas perennial ryegrass was more effective at accessing cabbage‐derived P (the main substrate in the compost). Oilseed rape was able to take up 20% of the total P applied as phosphate rock, whereas perennial ryegrass took up less than 5% of the total P applied from this material. Both pre‐ and post‐application solubilisation/transformation mechanisms were involved in supplying plant‐available P. Quantifying the relative contribution from individual P sources remains problematic even within this relatively simple system.