Lindsey Norgrove

Integrating mitigation and adaptation into development: the case of Jatropha curcas in sub-Saharan Africa

BART MUYS , L INDSEY NORGROVE , TENA ALAMIREW , RHODA B IRECH , EL I SA CH IR IN IAN , YOSEPH DELELEGN , ALBRECHT EHRENSPERGER , CAROL A . ELL I SON , ADEM FETO , BERNHARD FREYER , JAN GEVAERT , S IMON GM € UNDER , RAYMOND E . E . JONGSCHAAP , MANFRED KAUFMANN , JOD IE KEANE , MARC KEN I S , BON I FACE K ITEME , JACKSON LANGAT , REG INALD LY IMO , V IOLET MORAA , JAC INTA MUCHUGU , AKL I LU NEGUSS I E , CAROL INE OUKO , MATHUR IN W . ROUAMBA , I R IA SOTO , MANFRED W € ORGETTER , RA INER ZAH and RIGOBERTO ZETINA

Invasiveness risk of the tropical biofuel crop Jatropha curcas L. into adjacent land use systems: from the rumors to the experimental facts

Jatropha curcas L. produces seeds rich in non‐edible oil suitable for biodiesel but it has been categorized as invasive. Although not scientifically verified, this allegation has resulted in a cultivation ban in several countries. In this article we report an integrated series of observations and experimental findings from invasiveness research in Zambia. We studied the impacts of J. curcas plantations on adjacent land use systems focusing on spontaneous occurrence of seedlings, seed dispersal mechanisms, seed predation by animals, and germination success of dispersed seeds. No spontaneous regeneration was observed in land use systems adjacent to J. curcas plantations. Primary seed dispersal was limited, predominantly under the canopy of the mother plant. Rodents and shrews dispersed and predated J. curcas seeds and fruits. They transported the seeds up to 23 m from the sources and repositioned them in their burrows up to 0.7 m deep, but none of these seeds could establish. Germination experiments in adjacent land use systems revealed 4% germination success at the soil surface, and 65% if buried artificially at 1–2 cm depth, yet the latter is unlikely to occur under natural conditions. These findings show that J. curcas seeds may be dispersed by animals to adjacent land use systems, but no natural recruitment was observed given low germination on the surface and none in burrows. Altogether these results suggest that the plant currently does not show an elevated risk of invasion to adjacent land use systems, at least in the investigated case study. But more long‐term studies, also in other growing areas are needed to corroborate these results.

Slash-and-Burn Agriculture, Effects of

Slash and Burn agriculture is widely used in tropical Africa, Asia and South America. The technique is closely related to the oldest forms of land clearing and crop production and has sustained crop yields over millennia. Today slash and burn is used at considerably higher frequencies than in the past and on larger areas, causing concern that biodiversity is negatively affected. Slashed and burned areas are experiencing strong negative impact on biodiversity specifically on immobile, small species. However, these effects can be balanced if there is sufficient unaffected area from where re-colonization can re-establish species destroyed in the clearing and cropping phase.

Effects of biodiversity loss and restoration scenarios on tree-related ecosystem services

ABSTRACT In landscapes worldwide, trees in forests and agricultural lands have important ecological functions. Their loss may have important consequences for the delivery of ecosystem services (ES) to local communities, even if individual trees have low conservation values. This study explores the effect of land use and land use change on the provisioning of tree-related ES in a mixed Afromontane landscape in Ethiopia. First, we mapped the current distribution of tree-related ES using indicator ES, which represent the most characteristic ES for different land use types. More ES were characteristic for indigenous forest and agroforest, compared to exotic forest, cropland, and rangeland. A scenario analysis was conducted on the effect of tree species loss and restoration (RES) on ES. Two ES indices, ES diversity and ES multifunctionality, were used to evaluate the ES supply. The different behavior of the two ES indices in the species loss scenarios suggests that rare species have distinct traits that provide specific ES, which could not be compensated by the remaining common species. In tree species-poor landscapes, local communities prefer multifunctional tree species and these keep the diversity of ES supply high. Overall, our findings demonstrate that future conservation and restoration programs in mixed landscapes should both protect a large diversity of tree species, including rare tree species, and promote multifunctional keyston species to ensure a long-term and diverse ES supply. EDITED BY Edmundo Barrios

Source of mycorrhizal inoculum influences growth of Faidherbia albida seedlings

Poor land use management and practice inhibit the growth and establishment of tree seedlings in dryland areas. We assessed arbuscular mycorrhizal fungi (AM) status of Faidherbia albida (Del.) A. Chev. trees grown on different land uses. We quantified the growth and nutrient uptake of F. albida seedlings inoculated with AM from different sources. These efforts were based on soil and fine root samples from the rhizosphere soils of F. albida trees. AM root colonization was determined using the gridline intersect method. Spores were extracted by the wet sieving and decanting method and identified to genus level. The seedling experiment had a completely randomized one-factorial design with four treatments and five replications. Faidherbida albida seedlings were grown in a greenhouse. All in situ F. albida trees were colonized by AM fungi. AM root colonization of F. albida trees was significantly higher (P < 0.0086) in area exclosures than on lands used for grazing or cultivation. Spore abundance was significantly higher (P < 0.0014) in area exclosures followed by cultivated land and grazing land. Glomus was the dominant genus in all land-uses. AM-inoculated F. albida seedlings grew better (P < 0.05) than non-inoculated controls. Seedlings inoculated with AM from area exclosure had significantly (P < 0.05) higher growth and nutrient uptake than those inoculated with AM from grazing and cultivated land. This emphasizes the importance of the native soil AM potential for better establishment of seedlings to achieve optimum plant growth improvement and assist in rehabilitation of degraded arid lands.