A Rocha Kenya

Kenya

A Rocha Kenya

Kenya
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Hereward H.F.R.,Nottingham Trent University | Gentle L.K.,Nottingham Trent University | Ray N.D.,Nottingham Trent University | Sluka R.D.,A Rocha Kenya
African Journal of Marine Science | Year: 2017

Ghost crab (Ocypode species) burrow densities have previously been used as an indicator of anthropogenic impact. This study aimed to assess the burrow density of Ocypode species (O. ryderi and O. cordimanus) at four sites across Watamu Marine National Park, Kenya. Two sites were in front of hotel complexes (denoting a high degree of urbanisation), and two were in front of residential housing among coastal scrub (denoting a low degree of urbanisation). The findings reveal significantly higher burrow densities at sites in front of residential housing, which was the less developed area. This provides further evidence that Ocypode burrow densities can be used, where other methods would be impractical, to estimate the impact of some human activities along beach fronts, such as at Watamu Marine National Park. © 2017 NISC (Pty) Ltd.


Banks J.E.,University of Washington | Jackson C.,A Rocha Kenya | Hannon L.M.,University of Washington | Thomas C.M.,University of Washington | And 2 more authors.
African Journal of Ecology | Year: 2010

Although studies have explored how habitat structure and disturbance affect arthropod communities, few have explicitly tested the effects of both structure and disturbance level across trophic levels and phyla. We present here the results of a study conducted in the Arabuko-Sokoke Forest (ASF) of coastal Kenya, in which abundance of arthropods and one of their avian predators, the East Coast Akalat Sheppardia gunning sokokensis was compared in relatively undisturbed habitat (outside elephant roaming areas) and in disturbed habitat (inside elephant roaming areas). Vegetation structure in both areas was measured using several metrics, including leaf litter depth, understory vegetation density, animal disturbance and fallen log counts. Leaf litter and coleopteran abundance were higher outside the elephant roaming areas, whereas understory visibility, animal disturbance and dipteran diversity were much higher inside the elephant areas. Species composition of several arthropod taxa (e.g. Hymenoptera, Coleoptera, Diptera, Hemiptera and Araneae) was also influenced by degree of disturbance, whereas akalat abundance was inversely related to understory visibility. Our results suggest that differences in species sensitivity to habitat disturbance and vegetation structure across trophic levels should be incorporated into the management and conservation of rare and endangered species. © 2010 Blackwell Publishing Ltd.


Sindorf V.,A Rocha Kenya | Sindorf V.,University of Hawaii at Manoa | Cowburn B.,A Rocha Kenya | Cowburn B.,University of Oxford | Sluka R.D.,A Rocha Kenya
Environmental Biology of Fishes | Year: 2015

The tropical rocky intertidal is a poorly studied ecosystem of great ecological and commercial importance, warranting consideration when implementing coastal management strategies. Icthyofaunal diversity was studied at low tide in intertidal pools in the Watamu Marine National Park, Kenya (Western Indian Ocean). A total of 235 individuals in 15 families (34 species) were observed in 78 sampled quadrats. Gobiidae was the most prevalent family, comprising 25.5 % of individuals (five species), followed by Blenniidae with 18.3 % of individuals (five species), Pomacentridae with 15.7 % of individuals (ten species), and Labridae with 14 % of individuals (seven species). A Chao2 asymptotic richness estimate gave an expected asymptotic richness value of 96.36 (s.d. = 6.26), but is likely an underestimate of actual species richness due to limitations of visual census techniques. Half of species observed (52.7 %) were only observed as juveniles, indicating that these habitats may function as nurseries for reef-associated and deeper water fish. Other species were resident in this zone, with ten species being found in no other habitat in the surrounding area. This study suggests that the rocky intertidal contributes greatly to adjacent subtidal reef fish populations, which may support continuing local fisheries commerce through spillover of valuable species into the fishable waters. Conservation of this habitat may be of more importance than was previously considered due to its recent discovery as a possible nursery ground for offshore coral reef fish and the presence of species not found in other habitats in the area. © 2015, Springer Science+Business Media Dordrecht.


MacFarlane D.W.,Michigan State University | Kinzer A.T.,A Rocha Kenya | Banks J.E.,University of Washington
Forest Ecology and Management | Year: 2015

Remaining fragments of East African coastal dry forests contain very high levels of endemic species and are in critical need of conservation and restoration. Little is known about natural regeneration dynamics of these forests, or the potential for human action to aid recovery of lost structures and functions after deforestation/degradation. Here, data and analyses are presented from long-term monitoring plots in a 20. year-old forest restoration project in Gede, Kenya, in a fragment of Zanzibar-Inhambane (ZI) regional forest mosaic. Study results provided previously unavailable indigenous tree species growth rates and human-assisted forest regeneration rates for ZI forests and highlighted issues relevant to conserving and regenerating remnants of coastal dry forest throughout East Africa. Enrichment plantings accelerated recovery of indigenous tree species diversity and increased species density above natural levels. A strategy of inter-planting within existing natural regeneration, including leaving large relic trees, accelerated regrowth of the forest, but the main beneficiary of the strategy was exotic Azadirachta indica, which came to dominate significant areas. Analyses indicated that A. indica, which produces insecticidal compounds, was significantly altering the structure of arthropod communities; flying to ground-dwelling arthropod ratios were higher where A. indica made up a higher proportion of above-ground woody biomass. Management strategies appear to be mostly restoring indigenous forest structures, despite continued casual illegal tree cutting and invasion by A. indica. Analysis of illegally harvested trees highlighted the important role of indigenous tree species as a source of ecosystems services to local people; an important consideration for forest conservation planning worldwide. © 2015 Elsevier B.V.


MacFarlane D.W.,Michigan State University | Kinzer A.T.,A Rocha Kenya | Banks J.E.,University of Nairobi
Forest Ecology and Management | Year: 2015

Remaining fragments of East African coastal dry forests contain very high levels of endemic species and are in critical need of conservation and restoration. Little is known about natural regeneration dynamics of these forests, or the potential for human action to aid recovery of lost structures and functions after deforestation/degradation. Here, data and analyses are presented from long-term monitoring plots in a 20. year-old forest restoration project in Gede, Kenya, in a fragment of Zanzibar-Inhambane (ZI) regional forest mosaic. Study results provided previously unavailable indigenous tree species growth rates and human-assisted forest regeneration rates for ZI forests and highlighted issues relevant to conserving and regenerating remnants of coastal dry forest throughout East Africa. Enrichment plantings accelerated recovery of indigenous tree species diversity and increased species density above natural levels. A strategy of inter-planting within existing natural regeneration, including leaving large relic trees, accelerated regrowth of the forest, but the main beneficiary of the strategy was exotic Azadirachta indica, which came to dominate significant areas. Analyses indicated that A. indica, which produces insecticidal compounds, was significantly altering the structure of arthropod communities; flying to ground-dwelling arthropod ratios were higher where A. indica made up a higher proportion of above-ground woody biomass. Management strategies appear to be mostly restoring indigenous forest structures, despite continued casual illegal tree cutting and invasion by A. indica. Analysis of illegally harvested trees highlighted the important role of indigenous tree species as a source of ecosystems services to local people; an important consideration for forest conservation planning worldwide. © 2015.

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