Relationships among multiple aspects of agriculture's environmental impact and productivity: a meta‐analysis to guide sustainable agriculture

Given the pressures on land to produce ever more food, doing it ‘sustainably’ is growing in importance. However, ‘sustainable agriculture’ is complex to define, not least because agriculture impacts in many different ways and it is not clear how different aspects of sustainability may be in synergy or trade off against each other. We conducted a meta‐analysis to assess the relationships between multiple measures of sustainability using novel analytical methods, based around defining the efficiency frontier in the relationship between variables, as well as using correlation analysis. We define 20 grouped variables of agriculture's impact (e.g. on soil, greenhouse gas, water, biodiversity) and find evidence of both strong positive and negative correlations between them. Analysis based on the efficiency frontier suggests that trade‐offs can be ‘softened’ by exploiting the natural between‐study variation that arises from a combination of farming best practice and context. Nonetheless, the literature provides strong evidence of the relationship between yields and the negative externalities created by farming across a range of measures.     

The impact of land use and land cover change on biodiversity within and adjacent to Kibasira Swamp in Kilombero Valley,Tanzania

Wetlands are crucial ecosystems with multiple values and functions to a range of different stakeholders. The future of wetlands depends both on the legacy of the past and how they are currently used. Using 48 vegetation survey plots (0.08 ha) combined with Landsat 5 and 7 TM imagery, we assessed the influence of long‐term (1990–2011) land use and land cover change on the biodiversity of the Kibasira Swamp. Information on perceptions of adjacent communities on historical changes and drivers for the changes were also collected. Results showed an increase in the area covered by open water by 1% and forest by 4% between 1990 and 1998 whilst Cyperus papyrus L and cultivated land area decreased by 8% and 3%, respectively on the same period. Between 1998 and 2011, there was a decrease in areas covered by water by 35% and forest by 9% whereas C. papyrus L increased by 40% and cultivated land increased by 8%. These changes have affected the biodiversity of the swamp and adjacent to it as numbers of mammals have declined. However, the Swamp still provides extensive habitat for plants and bird species despite the ongoing human pressure. Interventions may be necessary to maintain biodiversity in Kibasira Swamp to ensure sustainable ecosystem services.     

Potential impacts on ecosystem services of land use transitions to second‐generation bioenergy crops in GB

We present the first assessment of the impact of land use change (LUC) to second‐generation (2G) bioenergy crops on ecosystem services (ES) resolved spatially for Great Britain (GB). A systematic approach was used to assess available evidence on the impacts of LUC from arable, semi‐improved grassland or woodland/forest, to 2G bioenergy crops, for which a quantitative ‘threat matrix’ was developed. The threat matrix was used to estimate potential impacts of transitions to either Miscanthus, short‐rotation coppice (SRC, willow and poplar) or short‐rotation forestry (SRF). The ES effects were found to be largely dependent on previous land uses rather than the choice of 2G crop when assessing the technical potential of available biomass with a transition from arable crops resulting in the most positive effect on ES. Combining these data with constraint masks and available land for SRC and Miscanthus (SRF omitted from this stage due to lack of data), south‐west and north‐west England were identified as areas where Miscanthus and SRC could be grown, respectively, with favourable combinations of economic viability, carbon sequestration, high yield and positive ES benefits. This study also suggests that not all prospective planting of Miscanthus and SRC can be allocated to agricultural land class (ALC) ALC 3 and ALC 4 and suitable areas of ALC 5 are only minimally available. Beneficial impacts were found on 146 583 and 71 890 ha when planting Miscanthus or SRC, respectively, under baseline planting conditions rising to 293 247 and 91 318 ha, respectively, under 2020 planting scenarios. The results provide an insight into the interplay between land availability, original land uses, bioenergy crop type and yield in determining overall positive or negative impacts of bioenergy cropping on ecosystems services and go some way towards developing a framework for quantifying wider ES impacts of this important LUC.     

The ontogeny of handling hard‐to‐process food in wild brown capuchins (Cebus apella apella): evidence from foraging on the fruit of Maximiliana maripa

We examined age‐related differences in wild brown capuchins' foraging efficiency and the food‐processing behaviors directed toward maripa palm fruit (Maximiliana maripa). A detailed comparison of the different foraging techniques showed that plucking the fruit from the infructescence constituted the main difficulty of this task. Foraging efficiency tended to increase with age, with a threshold at which sufficient strength allowed immatures by the age of three to reach adult‐level efficiency. Youngsters spent more time than older individuals browsing the infructescence and pulling the fruit in an attempt to harvest it. Infants tried to compensate for their inability to pluck fruit by adopting alternative strategies but with low payback, such as gnawing unplucked fruit and opportunistically scrounging others' partially processed food. Although around 2 years of age, young capuchins exhibited all of the behaviors used by adults, they did not reach adult‐level proficiency at feeding on maripa until about 3 years (older juveniles). We compared this developmental pattern with that of extractive foraging on beetle larvae (Myelobia sp.) hidden in bamboo stalks, a more difficult food for these monkeys [Gunst N, Boinski S, Fragaszy DM. Behaviour 145:195–229, 2008]. For maripa, the challenge was mainly physical (plucking the fruit) once a tree was encountered, whereas for larvae, the challenge was primarily perceptual (locating the hidden larvae). For both foods, capuchins practice for years before achieving adult‐level foraging competence, and the timeline is extended for larvae foraging (until 6 years) compared with maripa (3 years). The differing combinations of opportunities and challenges for learning to forage on these different foods illustrate how young generalist foragers (i.e. exploiting a large number of animal and plant species) may compensate for their low efficiency in extractive foraging tasks by showing earlier competence in processing less difficult but nutritious foods, such as maripa fruit. Am. J. Primatol. 72:960–973, 2010. © 2010 Wiley‐Liss, Inc.     

The impact of oral health on stated ability to eat certain foods; findings from the National Diet and Nutrition Survey of Older People in Great Britain

Objectives. To assess how the dental status of older people's mouths affected their stated ability to eat common foods. Design. Cross sectional study. Subjects. Survey was part of the oral health component of the nationwide British National Diet and Nutrition Survey: people aged 65 years and older. Two separate representative samples aged 65 and over: a free-living and an institutional sample. 881 free-living and 275 institution subjects had a dental exam and were interviewed about ability to eat key foods. Results. Significant percentages of free-living people had difficulty or could not eat at least 4 of 16 foods, and about 1 in 5 dentate stated they had difficulty eating or could not eat raw carrots, apples, well-done steak or nuts. More of the edentate subjects stated that they had difficulty eating than the dentate. Perceived chewing ability increased with increasing numbers of natural teeth and pairs of opposing posterior teeth. Subjects reporting a sociodental impact were more likely to consider that they were unable to eat foods that required more chewing. Associations remained valid after correction for the effects of age, sex, social class and denture wearing status and region. Perceived dryness did not affect significantly the stated ease of eating most foods. There were more dietary restrictions reported by the institution sample. Some foods, such as nuts, apples and raw carrots could not be eaten easily by over half of edentate people in the institution sample. Conclusions. The stated selection of foods are substantially affected by numbers of teeth and occluding pairs of posterior teeth and presence of full dentures in significant percentages of older people.