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Leuven, Belgium

Stuckens J.,M3 BIORES | Dzikiti S.,Stellenbosch University | Verstraeten W.W.,M3 BIORES | Verstraeten W.W.,Royal Netherlands Meteorological Institute | And 6 more authors.
Agricultural and Forest Meteorology | Year: 2011

Hyperspectral remote sensing for monitoring horticultural production systems requires the understanding of how plant physiology, canopy structure, management and solar elevation affect the retrieved canopy reflectance during different stages of the phenological cycle. Hence, the objective of this study was to set up and to interpret a hyperspectral time series for a mature and healthy citrus orchard in the Western Cape province of South Africa considering these effects. Based on the remotely sensed data, biophysical parameters at the canopy level were derived and related to known observed physiological and phenological changes at the leaf level and to orchard management. Fractions of mature fruit, flowers, and sunburnt leaves were considered, and indices related to canopy structure chlorophyll content and canopy water status were calculated. Results revealed small cover fractions of mature fruit, flowers and sunburnt leaves of respectively 2.1%, 3.1% and 7.0%, but the high spectral contrast between flowers and leaves allowed a successful classification of flowering intensity. Furthermore, it was shown that canopy level time series of vegetation indices were sensitive to changes in solar elevation and soil reflectance which could be reduced by applying an empirical soil line correction for the most affected indices. Most trends in vegetation indices at the canopy level could be explained by a combination of changes at the leaf level (chlorophyll, carotenoids, dry matter), changes in canopy structure (leaf area index and leaf angle distribution) and changes in cover fractions of vegetative flushes, flowers and sunburnt leaves. The transformed chlorophyll absorption ratio index over the optimised soil adjusted vegetation index (MCARI/OSAVI) was best related to leaf level trends in chlorophyll content. Seasonal changes in the photochemical reflectance index (PRI) were linked to inverse changes in the carotenoid-to-chlorophyll ratio. Canopy structure indices (the modified triangular vegetation index or MTVI2 and the standardized leaf area index determining index or sLAIDI) were sensitive to changes in leaf area index, average leaf angle as well to management interactions (pruning and harvest). Canopy water status was highly impacted during the spring flush due to expanding leaves that concealed trends in the underlying mature leaves. Seasonal trends in soil and weeds reflectance were related to changes in volumetric soil water content and to the earlier and reduced growth period of non-irrigated weeds. © 2011 Elsevier B.V.

Harley R.M.,Honorary Research Fellow | Harley R.M.,State University of Feira de Santana | Pastore J.F.B.,State University of Feira de Santana
Kew Bulletin | Year: 2010

A new species of Hyptis sect. Eriosphaeria (Lamiaceae) from Goiás (Brazil) is described, illustrated and compared with related species in sect. Eriosphaeria subsect. Passerinae. An evaluation of the species of the group and a key to identification is provided. © 2010 The Board of Trustees of the Royal Botanic Gardens, Kew.

Prance G.T.,Honorary Research Fellow
Kew Bulletin | Year: 2010

Summary: When Princess Augusta and Lord Bute, followed by Sir Joseph Banks and King George III, started gathering plants at Kew, conservation on the site can be said to have begun. Although the primary motive then was to assist the expansion of the British Empire and trade, rare plants were gathered and some became rare or extinct in the wild as their habitats were destroyed. The primary motive in the nineteenth century was not conservation, but the history of conservation at the Royal Gardens at Kew dates back to its very origins. Subsequent regimes at Kew maintained and added to the collections thereby adding to their conservation value. Many early collections are of species now listed within the IUCN categories of endangerment. Environmental awareness and concern had begun by the time that Professor Jack Heslop-Harrison became director and he was the first director actively to initiate specific conservation programmes such as seed banking and work on red data books. From then on conservation became an integral part of the work programme of Kew and the focus on conservation has increased with each subsequent director. This eventually led to the transformation of the embryonic seed banking activities into the Millennium Seed Bank, the largest and most important bank in the world for the conservation of the seeds of wild species. It currently holds just over ten percent of all seed plant species. Conservation at Kew over the past three decades has very much been a balance between ex situ work and in situ activities to help conservation in the overseas areas where Kew scientists have experience. Throughout the history of the gardens there has been a vital interest in economic botany that has developed from moving plants around the empire to much work on the sustainable use of plants and ecosystems thereby better equipping the institution to subsequently work on in situ conservation. Significant conservation activity at Kew has been possible because it is being supported by a solid research programme that includes such areas as systematics and molecular genetics and laboratories, a large herbarium and a large library. Kew has played an important role in stimulating conservation work elsewhere and such units as the Threatened Plants Unit of IUCN and Botanic Gardens Conservation International (BGCI) have their roots in Kew. Among other important conservation initiatives have been the creation of a unit to work with the implementation of the CITES treaty on the trade of endangered plants and a legal unit to work on issues of the Convention on Biological Diversity (CBD). There is no doubt that the Royal Botanic Gardens at Kew is at the forefront of plant conservation. © 2010 The Board of Trustees of the Royal Botanic Gardens, Kew.

Coelho A.A.O.P.,State University of Feira de Santana | Giulietti A.M.,State University of Feira de Santana | Harley R.M.,Honorary Research Fellow | Harley R.M.,State University of Feira de Santana | Yesilyurt J.C.,Natural History Museum in London
Kew Bulletin | Year: 2010

After a systematic revision of Portulaca L. (Portulacaceae) from Brazil, which included field work, studying herbarium specimens and relevant literature and original elements, the taxonomic observations and nomenclatural notes are here reported. Types were sought and most of them located. Synonymies (20), lectotypes (5), epitype (1) and neotype (1) are designated and defined. © 2010 The Board of Trustees of the Royal Botanic Gardens, Kew.

Obregon R.,University of Cordoba, Spain | Shaw M.R.,Honorary Research Fellow | Fernandez-Haeger J.,University of Cordoba, Spain | Jordano D.,University of Cordoba, Spain
SHILAP Revista de lepidopterologia | Year: 2015

As a result of recent field studies in the Iberian Peninsula, interactions between 17 parasitoid taxa and 17 butterfly species, and 9 species of Lycaenidae and 15 species of Formicidae are detailed and discussed. Several of these, which are presented quantitatively, are otherwise unrecorded in the literature, while others confirm previous records. Attention is drawn to the need for the deposition of voucher material and both careful and prolonged quantitative recording in order to understand and conserve these vulnerable aspects of biodiversity. © 2015, Soc Hispano-Luso-Amer Lepidopterologia-Shilap. All rights reserved.

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