Alice N. Pell

Complexity of Coupled Human and Natural Systems

Integrated studies of coupled human and natural systems reveal new and complex patterns and processes not evident when studied by social or natural scientists separately. Synthesis of six case studies from around the world shows that couplings between human and natural systems vary across space, time, and organizational units. They also exhibit nonlinear dynamics with thresholds, reciprocal feedback loops, time lags, resilience, heterogeneity, and surprises. Furthermore, past couplings have legacy effects on present conditions and future possibilities.

Analysis of condensed tannins: a review

Plant condensed tannins (proanthocyanidins, PAs) have both positive and negative effects on feed digestibility and animal performance, depending both on the quantity and biological activity of the tannins that are present. In this review, the chemistry and analysis of condensed tannins (PAs) are examined. Our first focus is on the complexity of the structures of condensed tannins and our second emphasis is on the analytical methods used to evaluate tannins. The section on methods is subdivided into a discussion of methods to determine the amount of condensed tannins or total phenolics in a sample and a section on methods to measure biological activity. The methods to measure reactivity include assays involving protein binding and precipitation, as well as those that involve enzymatic and microbial inhibition. The last section of the paper discusses structure–activity relationships and provides information on how to select appropriate assays for measurement of the quantity and activity of condensed tannins.

Coupled Human and Natural Systems

Abstract Humans have continuously interacted with natural systems, resulting in the formation and development of coupled human and natural systems (CHANS). Recent studies reveal the complexity of organizational, spatial, and temporal couplings of CHANS. These couplings have evolved from direct to more indirect interactions, from adjacent to more distant linkages, from local to global scales, and from simple to complex patterns and processes. Untangling complexities, such as reciprocal effects and emergent properties, can lead to novel scientific discoveries and is essential to developing effective policies for ecological and socioeconomic sustainability. Opportunities for truly integrating various disciplines are emerging to address fundamental questions about CHANS and meet societys unprecedented challenges.

Manure and Microbes: Public and Animal Health Problem?

Abstract Most environmental concerns about waste management either have focused on the effects of nutrients, especially N and P, on water quality or have emphasized odor problems and air quality. Microbes from manure are often low on the priority list for control and remediation, despite the fact that several out-breaks of gastroenteritis have been traced to livestock operations. The pathogens discussed in this paper include protozoans (Cryptosporidium parvum, Giardia spp.), bacteria (Listeria monocytogenes, Escherichia coli O157:H7, Salmonella spp., and Mycobacterium paratuberculosis), and some enteric viruses. Clinical symptoms, prospects for zoonotic infection, and control methods other than the use of antimicrobials are considered. Recommendations to avoid disease transmission include taking steps to ensure the provision of clean, unstressful environments to reduce disease susceptibility and the careful handling and spreading of manure from animals at high risk for infection, especially young calves. Composting and drying of manure decrease the number of viable pathogens. Environmental controls, such as filter strips, also reduce the risk of water contamination.

Nutritional quality of gorilla diets: consequences of age, sex, and season

We tested the effects of age, sex, and season on the nutritional strategies of a group of mountain gorillas (Gorilla beringei) in the Bwindi Impenetrable National Park, Uganda. Through observations of food intake of individual gorillas and nutritional analyses of dietary components over different seasons and environments, we estimated nutrient intake and evaluated diet adequacy. Our results suggest that the nutritional costs of reproduction and growth affect nutrient intake; growing juveniles and adult females ate more food and more protein per kilogram of metabolic body mass than did silverbacks. The diets of silverback males, adult females, and juveniles contained similar concentrations of protein, fiber, and sugar, indicating that adult females and juveniles did not select higher protein foods than silverbacks but rather consumed more dry matter to ingest more protein. Juveniles consumed more minerals (Ca, P, Mg, K, Fe, Zn, Mn, Mo) per kilogram of body mass than adult females and silverback males, and juveniles consumed diets with higher concentrations of phosphorous, iron, and zinc, indicating that the foods they ate contained higher concentrations of these minerals. Seasonally, the amount of food consumed on a dry weight basis did not vary, but with increased frugivory, dietary concentrations of protein and fiber decreased and those of water-soluble carbohydrates increased. Energy intake did not change over the year. With the exception of sodium, gorillas ate diets that exceeded human nutrient requirements. A better understanding of the relative importance of food quantity and quality for different age–sex classes provides insights into the ways in which gorillas may be limited by food resources when faced with environmental heterogeneity.

Research Principles for Developing Country Food Value Chains

From farm to table, multidisciplinary research is needed to improve the economic benefit of food production in the developing world. Food value chains (FVCs) comprise all activities required to bring farm products to consumers, including agricultural production, processing, storage, marketing, distribution, and consumption. FVCs are changing rapidly in developing countries (DCs), because of population and income growth; urbanization; and the expansion, globally and domestically, of modern food retailing, distribution, and wholesaling firms (1, 2). One such change is that consumers and regulators increasingly demand product-specific characteristics beyond price—including nutrient content; food safety certification; and indicators of impacts on natural resources, greenhouse gas emissions, and farmworkers. To accommodate these multidimensional demands, regulators and firms are developing new multiattribute product labeling and production standards. We outline below ways in which scientists must integrate existing disciplinary evidence into rigorous models and must develop measures and methods to evaluate the multidimensional performance of FVCs.

A Method for Isolating Condensed Tannins from Crude Plant Extracts with Trivalent Ytterbium

A method to precipitate condensed tannin from crude plant extracts using trivalent ytterbium has been developed. The new method requires less time and resources than the condensed isolation procedure using Sephadex LH-20 recommended by Hagerman (1991, Tannin Analysis, Miami University, Oxford, OH, USA). The absorbance of the preparations obtained by precipitation with trivalent ytterbium was similar to the preparations obtained with the original isolation procedure, when the acid butanol method (Porter et al 1986, Phytochemistry1 223–230) was used to measure condensed tannins. Condensed tannins were isolated from crude plant extracts of three plant species, Desmodium ovalifolium, Gliricidia sepium and Manihot esculenta, and the condensed tannin content of the lyophilised leaf tissue was determined. For each plant species, the amounts of the soluble, insoluble and fibre-bound condensed tannins were estimated using five different standards. These standards included two tannin preparations obtained either by (1) isolation with Sephadex LH-20, or (2) by the precipitation with trivalent ytterbium and three external standards: (3) cyanidin, (4) delphinidin and (5) purified quebracho (Schinopsis balansae). When external standards were used (cyanidin, delphinidin, purified quebracho), it was likely that the condensed tannin content of the plant tissue would be under- or overestimated. When an internal standard based on the isolated tannin from the respective plant species was used, accurate estimates were obtained.

Characteristics of neutral detergent-soluble fiber fermentation by mixed ruminal microbes

Abstract A new method for determining neutral detergent-soluble fiber (NDSF) estimates the non-starch polysaccharide present in 90% ethanol-insoluble residue (EIR) but absent from neutral detergent residue (NDF). Unextracted feeds, EIR and NDF of feeds high in pectic substances were fermented in vitro with mixed ruminal microbes and gas production was measured. Soybean hulls were fermented for 48 h, and all other feeds for 24 h. Fermentation kinetics of NDSF were determined from gas curves produced by point by point subtraction of the gas production curves of NDF from those of EIR. Single-pool logistic fermentation rates and lag times for NDSF and NDF were determined from the gas production data. The single-pool logistic rates for NDSF for dried citrus pulp, dried beet pulp, soybean hulls, mature alfalfa stems and leaves and immature alfalfa stems and leaves were 0.13, 0.16, 0.05, 0.11, 0.14, 0.18 and 0.13 h −1 , respectively. Fermentation rates tended to be faster and lag times shorter for NDSF than for NDF. Acetate to propionate ratios were numerically higher for EIR fermentations than for unextracted feeds or NDF. The fermentation characteristics of NDSF for the feeds in this study are consistent with reports of pectic substance fermentations indicating that NDSF does describe the soluble fiber fraction. The NDSF and gas production measurement methods offer nutritionally relevant ways to estimate soluble fiber content and its digestion characteristics in feedstuffs.

Fecal Bacterial Diversity in a Wild Gorilla

ABSTRACT We describe the bacterial diversity in fecal samples of a wild gorilla by use of a 16S rRNA gene clone library and terminal-restriction fragment length polymorphism (T-RFLP). Clones were classified as Firmicutes, Verrucomicrobia, Actinobacteria, Lentisphaerae, Bacteroidetes, Spirochetes, and Planctomycetes. Our data suggest that fecal populations did not change temporally, as determined by T-RFLP.

Nutritional composition of the diet of the gorilla (Gorilla beringei): a comparison between two montane habitats

The mountain gorilla (Gorilla beringei beringei) lives in two geographically separated populations, Bwindi Impenetrable National Park, Uganda and in three national parks spanning the Virunga mountain region in Rwanda, Democratic Republic of Congo, and Uganda. The altitude, climate and plant composition of these habitats differ. Our goal was to compare the diets of gorillas living in each of these habitats. The nutrients in staple foods and in the diets of individuals in a group of gorillas in Bwindi (N =12 individuals) and a group in the Virungas (N =7 individuals) were compared to determine if differences in dietary composition affected concentrations of nutrients in their diets. At both sites gorilla diets consisted primarily of herbaceous leaves, but the diet of Bwindi gorillas contained more tree leaves, fruit, pith and dry wood, and fewer stems. Despite differences in habitat and dietary composition, the nutrient concentrations in both gorilla diets were remarkably similar. On a dry matter basis, the diets and staple foods of Bwindi and Virunga gorillas contained similar concentrations of crude protein (CP), fibre (NDF) and non-structural carbohydrates (TNC). Bwindi gorillas ate diets containing 18% CP, 43% NDF and 19% TNC on a dry-matter basis, whilethedietsoftheVirungagorillascontained17%CP,41%NDFand18%TNC.Ourresultsdemonstratethatgorillas consume diets that differ by plant species and part, but contain similar concentrations of nutrients. This suggests that classifying animals by broad dietary strategy (e.g. frugivory and folivory) does not provide a reliable indicator of the nutritional quality of their diet, and that our previous assumptions about these categories should be re-evaluated.