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BERESFORD A.E.,Center for Conservation Science | BUCHANAN G.M.,Center for Conservation Science | PHALAN B.,Oregon State University | ESHIAMWATA G.W.,BirdLife International Africa Partnership Secretariat | And 5 more authors.
Environmental Conservation | Year: 2017

The loss of natural habitats is a major threat to biodiversity, and protected area designation is one of the standard responses to this threat. However, greater understanding of the drivers of habitat loss and of the circumstances under which protected areas succeed or fail is still needed. We use visual assessment of satellite images to quantify land-cover change over periods of up to 30 years in and around a matched sample of protected and unprotected Important Bird and Biodiversity Areas (IBAs) in Africa. We modelled the annual survival of forests and other natural land covers as a function of a range of environmental and anthropic predictors of plausible drivers. The best-supported model indicated that survival rates of natural land cover were highest in steeper areas, at higher altitudes, in areas with lower human population densities and in areas where the cover of natural habitats was already higher at the start of the period. Survival rates of natural land cover in protected areas were, on average, around twice those in unprotected areas, but the differences between them varied along different environmental gradients. The overall survival rates of both protected and unprotected forests were significantly lower than those of other natural land-cover types, but the net benefit of protection, in terms of the absolute difference in rates of loss between protected and unprotected sites, was higher in forests. Interaction terms indicated that as slope and altitude increased, the natural protection offered by topography increasingly nullified the additional benefits of legislative protection. Furthermore, protected area designation offered reduced additional benefits to the survival of natural land cover in areas where rates of conversion were higher at the start of the observation period. Variation in the impacts of protected area status along different environmental gradients indicates that targets to improve the world's protected area network, such as Aichi Target 11 of the Convention on Biological Diversity, need to look beyond simple area-based metrics. Our methods and results contribute to the development of a protocol for prioritizing places where protection is likely to have the greatest effect. Copyright © Foundation for Environmental Conservation 2017


Butchart S.H.M.,BirdLife International | Butchart S.H.M.,United Nations Environment Programme World Conservation Monitoring Center | Scharlemann J.P.W.,United Nations Environment Programme World Conservation Monitoring Center | Evans M.I.,BirdLife International | And 49 more authors.
PLoS ONE | Year: 2012

Protected areas (PAs) are a cornerstone of conservation efforts and now cover nearly 13% of the world's land surface, with the world's governments committed to expand this to 17%. However, as biodiversity continues to decline, the effectiveness of PAs in reducing the extinction risk of species remains largely untested. We analyzed PA coverage and trends in species' extinction risk at globally significant sites for conserving birds (10,993 Important Bird Areas, IBAs) and highly threatened vertebrates and conifers (588 Alliance for Zero Extinction sites, AZEs) (referred to collectively hereafter as 'important sites'). Species occurring in important sites with greater PA coverage experienced smaller increases in extinction risk over recent decades: the increase was half as large for bird species with&50% of the IBAs at which they occur completely covered by PAs, and a third lower for birds, mammals and amphibians restricted to protected AZEs (compared with unprotected or partially protected sites). Globally, half of the important sites for biodiversity conservation remain unprotected (49% of IBAs, 51% of AZEs). While PA coverage of important sites has increased over time, the proportion of PA area covering important sites, as opposed to less important land, has declined (by 0.45-1.14% annually since 1950 for IBAs and 0.79-1.49% annually for AZEs). Thus, while appropriately located PAs may slow the rate at which species are driven towards extinction, recent PA network expansion has under-represented important sites. We conclude that better targeted expansion of PA networks would help to improve biodiversity trends. © 2012 Butchart et al.


Palla F.,University Pierre and Marie Curie | Picard N.,CIRAD | Abernethy K.A.,Institute Of Recherche En Ecologie Tropicale | Abernethy K.A.,University of Stirling | And 7 more authors.
Plant Ecology and Evolution | Year: 2011

Background and aims - The Lopé National Park in Gabon, recently added to the UNESCO world heritage list, presents a mosaic of forest and savanna that dynamically changes. Conserving this landscape requires an understanding of the forest dynamics. This study aims at defining a forest typology at Lopé in relation with its dynamics. Methods - Floristic and structural characteristics for 265 tree species belonging to 55 families were measured in 258 sampling plots in the Lopé National Park. Multivariate analysis of these data was used to partition the sampling plots into groups on the basis of their floristic or structural characteristics. Key results - Five structural forest types and six floristic forest types were identified. This typology showed that the forests in the forest-savanna mosaic of Lopé organize themselves along a gradient of forest recovery, from young forests to mature forests. Typical pioneer species are associated with the youngest forest stages. The gradient on the species also corresponds to a geographical gradient on the sampling plots, associated with features like altitude, rocks, or hydrography. Conclusions - Five forest types were defined on the basis of species abundances. The snapshot of forest types characterizes a dynamic process of forest regeneration. © 2011 National Botanic Garden of Belgium and Royal Botanical Society of Belgium.


Ndang'ang'a P.K.,BirdLife International Africa Partnership Secretariat | Ndang'ang'a P.K.,Jomo Kenyatta University of Agriculture and Technology | Njoroge J.B.M.,Jomo Kenyatta University of Agriculture and Technology | Ngamau K.,Jomo Kenyatta University of Agriculture and Technology | And 3 more authors.
Ostrich | Year: 2013

We examined the effects of crop diversity on avian species richness and abundance in the highland farmlands of Nyandarua, Kenya. We surveyed birds using point counts and recorded habitat data at the same locations estimating cover and growth stage of all crop types, whether they were grown as intercrops or monocrops, and the dominant surrounding vegetation type. An index of crop diversity was calculated from the percentage cover of the different crop types. The effects of these habitat variables on bird species richness, abundance of foraging guilds and the abundance of each of the 12 most common species were examined using linear mixed models. Crop diversity had significant positive effects on species richness. Cereal cover had negative effects on species richness, overall bird abundance and abundance of granivores. Occurrence of cultivation/fallow and mixed vegetation as the dominant habitat surrounding crop plots positively influenced granivores' abundance, and the abundance of Speckled Mousebird Colius striatus, a pest species, was favoured by increasing orchard cover and occurrence of wooded and shrub vegetation as the dominant surrounding vegetation type. The study confirmed that heterogeneity brought about by increased crop diversity and reduced cereal cover within cultivations contributed to enhancement of farmlands as habitats for birds. © 2013 Copyright NISC (Pty) Ltd.


Ndang'ang'a P.K.,BirdLife International Africa Partnership Secretariat | Ndang'ang'a P.K.,Jomo Kenyatta University of Agriculture and Technology | Njoroge J.B.M.,Jomo Kenyatta University of Agriculture and Technology | Vickery J.,The Royal Society for the Protection of Birds
International Journal of Pest Management | Year: 2013

Bird exclusion experiments on kale (Brassica sp.) plants were undertaken to quantify the extent to which foraging birds contributed to reducing the densities and impact of invertebrate pests. During the dry season, significantly higher leaf-area loss, aphid and thrips abundance were recorded in bird-excluded compared with control plants, suggesting that birds could make an important contribution to pest control. On average, per week, during the dry season, exclusion of birds from kale plants led to both a marked increase (130%) in the number of leaves infested with aphids and an increase in leaf damage by pests (about three times greater than when birds had access to the kale plants). These results suggest that, in the dry season, foraging birds reduce the invertebrate pest load and hence the amount of leaf damage in kale, and that this may, in turn, have an impact of the market value of the crop. We recommend that measures to enhance avian insectivory should be explored and encouraged in order to better take advantage of birds in integrated pest management of kale and possibly other crops. © 2013 Copyright Taylor and Francis Group, LLC.


Ndang'ang'a P.K.,BirdLife International Africa Partnership Secretariat | Ndang'ang'a P.K.,Jomo Kenyatta University of Agriculture and Technology | Njoroge J.B.M.,Jomo Kenyatta University of Agriculture and Technology | Githiru M.,Ornithology Section
Ostrich | Year: 2013

We examined the effects of vegetation composition and structure on bird species diversity and richness of foraging guilds in the highland agricultural landscape of Nyandarua, Kenya. Bird point counts and vegetation surveys were undertaken during four sampling periods. Linear mixed models were used to examine the effects of vegetation variables on bird species diversity and richness of respective foraging guilds, and logistic generalised linear models used to examine vegetation effects on the presence/absence of the 17 most common bird species. Bird species diversity increased with increasing density of woody plant species and vegetation structural heterogeneity. Two gradients of increasing vegetation structural heterogeneity were most important in influencing bird community composition and had positive effects on species diversity and the presence of most of the species assessed: (1) increasing closed cover due to woody plant density, which also had positive effects on species richness of frugivores and nectarivores, but negative effects on carnivores, and (2) increasing fallow and cultivation versus decreasing grassland/pasture cover, which also had a positive effect on species richness of granivores and omnivores. This study reaffirms the need to maintain a structurally rich agricultural landscape for it to support agrobiodiversity. © 2013 Copyright © NISC (Pty) Ltd.


Kariuki Ndang'Ang'A P.,BirdLife International Africa Partnership Secretariat | Kariuki Ndang'Ang'A P.,Jomo Kenyatta University of Agriculture and Technology | Njoroge J.B.M.,Jomo Kenyatta University of Agriculture and Technology | Ngamau K.,Jomo Kenyatta University of Agriculture and Technology | And 3 more authors.
Bird Study | Year: 2013

Capsule Most birds in a Kenyan highland agroecosystem foraged from the ground, potentially contributing to weed regulation, and invertebrate intake rates by aerial foraging insectivores were high, indicating that birds could contribute to pest regulation. Aims Bird foraging behaviour and its implications for provision of ecosystem services and crop damage was investigated. Methods Detailed observations of foraging birds in relation to substrates used and food items consumed were undertaken within cultivated areas during dry and wet seasons. Results Most birds foraged from the ground, often consuming seeds, fruits and flowers from weeds rather than crop plants. The relatively high rate of invertebrate intake by two aerial foraging species and the high number of insectivorous bird species recorded in the area suggest that invertebrate predation could also be high and potentially contribute to pest regulation. Species-specific differences in the habitats birds used and prey taken were also identified, providing an indication of species likely to contribute to invertebrate and weed pest control and those likely to cause crop damage. Conclusion The results describe species-specific avian foraging behaviour in African farmland that may be used in informing agricultural management practices to enhance beneficial species and reduce impacts of crop-damaging ones. © 2013 Copyright British Trust for Ornithology.


Marsden S.J.,Manchester Metropolitan University | Loqueh E.,Society for the Conservation of Nature in Liberia | Takuo J.M.,Cameroon Biodiversity Conservation Society | Hart J.A.,Lukuru Foundation | And 5 more authors.
ORYX | Year: 2015

Estimating population sizes in the heavily traded grey parrots of West and Central Africa would provide insights into conservation status and sustainability of harvests. Ideally, density estimates would be derived from a standardized method such as distance sampling, but survey efforts are hampered by the extensive ranges, patchy distribution, variable abundance, cryptic habits and high mobility of the parrots as well as by logistical difficulties and limited resources. We carried out line transect distance sampling alongside a simpler encounter rate method at 10 sites across five West and Central African countries. Density estimates were variable across sites, from 0–0.5 individuals km−2 in Côte d'Ivoire and central Democratic Republic of the Congo to c. 30 km−2 in Cameroon and > 70 km−2 on the island of Príncipe. Most significantly, we identified the relationship between densities estimated from distance sampling and simple encounter rates, which has important applications in monitoring grey parrots: (1) to convert records of parrot groups encountered in a day's activities by anti-poaching patrols within protected areas into indicative density estimates, (2) to confirm low density in areas where parrots are so rare that distance sampling is not feasible, and (3) to provide a link between anecdotal records and local density estimates. Encounter rates of less than one parrot group per day of walking are a reality in most forests within the species’ ranges. Densities in these areas are expected to be one individual km−2 or lower, and local harvest should be disallowed on this basis. Copyright © Fauna & Flora International 2015


Ndang'ang'a P.K.,BirdLife International Africa Partnership Secretariat | Barasa F.M.,Nature Kenya | Kariuki M.N.,BirdLife International Africa Partnership Secretariat | Muoria P.,Nature Kenya
African Journal of Ecology | Year: 2016

The coastal forests of Kenya are conservation priorities hosting high levels of biodiversity. Monitoring of biodiversity in these forests is therefore necessary to understand and reverse negative trends in good time. Using the Important Bird Area (IBA) monitoring framework, a participatory approach, state (habitat condition), pressure (threats) and response (conservation action) indicators of twelve coastal Kenya forest IBAs were assessed from 2004 to 2011. Trends for these indicators were assessed at six sites for which sufficient data existed: Arabuko-Sokoke, Dakatcha Woodlands, Gede Ruins, Lower Tana River, Shimba Hills and Taita Hills, and baselines were described for remaining six. Changes were always small, but state deteriorated in Gede, Lower Tana and Shimba Hills, remained the same (unfavourable) in Arabuko-Sokoke and Dakatcha, and improved in Taita Hills. Pressure reduced in Arabuko-Sokoke, Dakatcha and Taita Hills, deteriorated in Lower Tana and Shimba Hills and remained the same (medium) in Gede. Response improved in Dakatcha, remained the same (medium) in Shimba Hills, and deteriorated in the rest. As there was an apparent overall deterioration in the forests assessed, improved management of the protected sites and increased conservation action through community engagement around protected areas and within the nonprotected IBAs are recommended. © 2016 John Wiley & Sons Ltd.

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