Browsing by Author "Lovett, Jon C."
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Item Back to Africa: Monitoring Post-Hydropower Restoration to Facilitate Reintroduction Of An Extinct-In-The-Wild Amphibian(2014-08) Vandvik, Vigdis; Måren, Inger E.; Ndangalasi, Henry J.; Lovett, Jon C.Monitoring of the ecological efficiency of different restoration and mitigation measures is important to inform decision-making but can be challenging, especially in remote and low-resource settings. Species composition of the vegetation is sensitive to environmental variation, and can thus be used in restoration assessment, but this requires statistical approaches that can accommodate multivariate responses. We use principal response curves (PRC) to assess the efficiency of post-hydropower mitigation measures installed to secure the reintroduction of an extinct-in-the-wild amphibian back into its only native habitat. The endemic ovoviviparous Kihansi spray toad Nectophrynoides asperginis is only known from a wetland in the Lower Kihansi River Gorge in the Eastern Arc Mountains in Tanzania. River flow was diverted from the gorge for hydropower production in 1999, causing the spray wetland to desiccate, consequently threatening the toad and other plant and animal species dependent on the spray-zone habitat. To mitigate the toad population collapse, a sprinkler system was installed over a limited section of the original sprayzone wetlands to mimic the waterfall spray and toads were taken to the USA for ex situ breeding. The decline, extinction, ex situ breeding, and planned reintroduction of the species has driven substantial research on Kihansi spray toad biology. In contrast, the efficiency of the mitigation measures in restoring the spray-zone wetland habitat required for its successful reintroduction has not been formally evaluated. Here, we analyze re-sampled vegetation data from the spray-zone wetland over a period of eight years by means of principal response curves to investigate if the post-hydropower mitigation measures have successfully restored the pre-hydropower ecosystem. The results show that the spray-zone vegetation is recovering. The wetland flora and especially species important to the Kihansi spray toad have increased and the restored ecosystem has stabilized, favoring the reintroduction of the Kihansi spray toad to its native habitat. However, the wetland ecosystem is not restored entirely and continued mitigation measures are needed. Continued monitoring is essential to support evidence-based restoration, and we conclude that assessment based on vegetation monitoring coupled with principal response curve analyses provides a cost-effective and efficient monitoring tool for such projeItem Back To Africa: Post Hydropower-Project Mitigation Effects on Wetland Vegetation in Relation To The Conservation of an Endemic Amphibian(Wiley, 2012-07) Maren, Inger E.; Vandvik, Vigdis; Ndangalasi, Henry J.; Taplin, James; Mbago, Frank; Lovett, Jon C.Developing countries are home to much of the world’s biodiversity due to their location in areas of high species richness and their native vegetation has not yet been totally transformed by human activity. Enabling economic and social development to proceed whilst retaining the high environmental values is central to the principle of sustainability, but activities under these three pillars of sustainability are often in conflict. Provision of energy from environmentally sound technologies is critical for economic development in Africa and hydropower offers a reliable way of doing this. The Lower Kihansi Hydropower Project in Tanzania is a model example of the application of technology to minimise environmental impact. However, although the footprint of the project is relatively small, it is located in a biodiversity hotspot where almost any development will have negative impacts on its many restricted range species. Globally, hydropower projects have been associated with negative biological impacts of flooding of the reservoir impounded by the dam. Less attention has been paid to the immediate downstream effects of dams, such as the loss of waterfall spray zones. We analysed the effects of the mitigation efforts by the installment of a sprinkler system to prevent extinction of the Kihansi Spray Toad Nectophrynoides asperginis, which is only known from this short section of the Kihansi River. We analysed re-sampled vegetation plots in the spray wetland habitat over a period of eight years to test if the post-hydropower project mitigation has aided the vegetation composition in approaching similarity to that of the pre-hydropower project conditions, testing two hypotheses dealing with habitat responses to the mitigation measures; (i) Does the instalment of the sprinkler system alter plant species composition in the former waterfall spray zone in relation to the controls? (ii) Do the mitigation measures succeed in restoring the wetland habitat and hence facilitate the re-introduction of the Kihansi Spray Toad? The results clearly show that the post-hydropower mitigations are successful as the vegetation cover and species composition with time approach that of the pre-hydropower project conditions. Overall, the proportion of weedy species decreased and wetland species increased with time since mitigation. However, results suggest that the wetland has not entirely reverted back to pre-project conditions and continued mitigation measures are needed. In conclusion, this positive trend in the wetland habitat development due to the mitigation measures may facilitate the reintroduction of the in situ extinct Kihansi Spray Toad in the near future.Item The biological importance of the Eastern Arc Mountain of Tanzania and Kenya(2007-01) Burgess, Neil D.; Butynski, Thomas M.; Cordeiro, Norbert J.; Doggart, Nike; Fjeldså, Jon; Howell, Kim; Kilahama, Felician B.; Loader, Simon; Lovett, Jon C.; Mbilinyi, Boniface P.; Menegon, Michele; Moyer, David; Nashanda, Evarist; Perkin, Andrew; Rovero, Francesco; Stanley, William T.; Stuart, Simon N.The Eastern Arc Mountains are renown in Africa for high concentrations of endemic species of animals and plants. Thirteen separate mountain blocks comprise the Eastern Arc, supporting around 3300 km2 of sub-montane, montane and upper montane forest, less than 30% of the estimated original forested area. At least 96 vertebrate species are endemic, split as follows: 10 mammal, 19 bird, 29 reptile and 38 amphibian species. This includes four endemic or nearly endemic species of primate – the Sanje Mangabey, the Iringa Red Colobus, the Mountain Galago and the new Kipunji monkey that forms its own monotypic genus. A further 71 vertebrate species are near-endemic. At least 800 vascular plant species are endemic, almost 10% of these being trees. These endemics include the majority of the species of African violet – Saintpaulia, a well-known flowering plant in Western households. An additional 32 species of bryophytes are also endemic. Many hundreds of invertebrates are also likely to be endemic, with data for butterflies, millipedes and dragonflies indicating potential trends in importance. Seventy-one of the endemic or near-endemic vertebrates are threatened by extinction (8 critical, 27 endangered, 36 vulnerable), with an additional seven wide ranging threatened species. Hundreds of plant species are also threatened. Most Eastern Arc endemics are closed-forest specialists and comprise taxa with an ancient history and those of more recent origin, including some possessing ancient affinities with taxa from West Africa, Madagascar, and even South America and Southeast Asia. Mountain block prioritisation for biodiversity conservation shows that Udzungwas, East Usambaras and Ulugurus are the most important blocks, with other important blocks being the Ngurus and West Usambaras. Rankings are correlated closely with the area of remaining forest. Most of the remaining forest is found within nearly 150 Government Forest Reserves, with 106 of these managed nationally for water catchment, biodiversity and soil conservation and where forest exploitation is not allowed. Outside these areas most forest has been cleared, except in small village burial/sacred sites, a few Village Forest Reserves, and inaccessible areas. In most Eastern Arc Mountains the local populations have not encroached beyond the reserve boundaries to develop farms, but forest resources within the boundaries are used for fuel and building materials and some forests are heavily degraded. Fire is also a problem as it enters and destroys forests during the dry seasons. The future of the biodiversity on the Eastern Arc Mountains is closely tied to management policies and capacity of the Tanzania Forestry and Beekeeping Division, Tanzania National Parks Authority, and Kenya Forest Department. Supporting these agencies in their mandated job is an essential conservation investment over the longer term.Item A critically endangered new species of Nectophrynoides (Anura: Bufonidae) from the Kihansi Gorge, Udzungwa Mountains, Tanzania(1997-12) Poynton, John C.; Howell, Kim; Clarke, Barry T.; Lovett, Jon C.A new species of the Tanzanian ovoviviparous dwarf toad Nectophrynoides is described from the Kihansi River Gorge in the Udzungwa Mountains, and a key to the genus provided. The new species, currently known only from small patches of spray-dependent wetland vegetation associated with Kihansi Gorge waterfalls, is probably the most vulnerable member of this genus on account of the Lower Kihansi Hydropower Project which is due to go on-line in 1999. This project will significantly reduce the river flow into the gorge and consequently the amount of spray that maintains a unique plant and animal community. Measures are suggested for improving chances of long-term survival of the species.Item Effect of The Lower Kihansi Hydropower Project and Post-Project Mitigation Measures On Wetland Vegetation In Kihansi Gorge, Tanzania(Springer, 2005-02) Quinn, Claire H.; Ndangalasi, Henry J.; Gerstle, John H.; Lovett, Jon C.Reduction in flow of the Lower Kihansi River, Tanzania, caused by implementation of a hydropower project in May 2000 has the potential to lead to changes in vegetation composition of spray maintained wetlands. These wetlands are the only known habitat for the Kihansi Spray Toad, Nectophrynoides asperginis. In this paper, change over time is assessed by comparing samples taken in 1998 before reduction in flow, with those taken in 2000 after reduction in flow, in 2001 following installation of a sprinkler system built to maintain the wetlands and in 2002 eighteen months after sprinkler installation. The vegetation was found to change markedly following initiation of the project, with marsh and stream side species dying back and weedy species entering the wetland. The wetland continued to change following installation of the sprinkler system and has not appeared to have reverted back towards the pre-project condition, although diversity and the proportion of marsh and stream side species are greater in 2002 than in 1998.Item Increasing Carbon Storage in Intact African Tropical Forests(2009-03) Lewis, Simon L.; Gonzalez, Gabriela L.; Sonke, Bonaventure; Baffoe, Kofi A.; Baker, Timothy R.; Ojo, Lucas O.; Phillips, Oliver L.; Reitsma, Jan M.; White, Lee; Comiskey, James A.; Djuikouo, Marie N. K.; Ewango, Corneille E. N.; Feldpausch, Ted R.; Hamilton, Alan C.; Gloor, Manuel; Hart, Terese; Hladik, Annette; Lloyd, Jon; Lovett, Jon C.; Makana, Jean R.; Malhi, Yadvinder; Mbago, Frank M.; Ndangalasi, Henry J.; Peacock, Julie; Peh, Kelvin S. H.; Sheil, Douglas; Sunderland, Terry; Swaine, Michael D.; Taplin, James; Taylor, David; Thomas, Sean C.; Votere, Raymond; Woll, HannsjorgThe response of terrestrial vegetation to a globally changing environment is central to predictions of future levels of atmospheric carbon dioxide. The role of tropical forests is critical because they are carbon-dense and highly productive. Inventory plots across Amazonia show that old-growth forests have increased in carbon storage over recent decades, but the response of one-third of the world's tropical forests in Africa is largely unknown owing to an absence of spatially extensive observation networks. Here we report data from a ten-country network of long-term monitoring plots in African tropical forests. We find that across 79 plots (163 ha) above-ground carbon storage in live trees increased by 0.63 Mg C ha(-1) yr(-1) between 1968 and 2007 (95% confidence interval (CI), 0.22-0.94; mean interval, 1987-96). Extrapolation to unmeasured forest components (live roots, small trees, necromass) and scaling to the continent implies a total increase in carbon storage in African tropical forest trees of 0.34 Pg C yr(-1) (CI, 0.15-0.43). These reported changes in carbon storage are similar to those reported for Amazonian forests per unit area, providing evidence that increasing carbon storage in old-growth forests is a pan-tropical phenomenon. Indeed, combining all standardized inventory data from this study and from tropical America and Asia together yields a comparable figure of 0.49 Mg C ha(-1) yr(-1) (n = 156; 562 ha; CI, 0.29-0.66; mean interval, 1987-97). This indicates a carbon sink of 1.3 Pg C yr(-1) (CI, 0.8-1.6) across all tropical forests during recent decades. Taxon-specific analyses of African inventory and other data suggest that widespread changes in resource availability, such as increasing atmospheric carbon dioxide concentrations, may be the cause of the increase in carbon stocks, as some theory and models predict.Item Land cover change and carbon emissions over 100 years in an African biodiversity hotspot(2016-07) Willcock, Simon; Phillips, Oliver L.; Platts, Philip J.; Swetnam, Ruth D.; Balmford, Andrew; Burgess, Neil D.; Ahrends, Antje; Bayliss, Julian; Doggart, Nike; Doody, Kathryn; Fanning, Eibleis; Green, Jonathan; Hall, Jaclyn; Howell, Kim; Lovett, Jon C.; Marchant, Rob A.; Marshall, Andrew R.; Mbilinyi, Boniface P.; Munishi, Pantaleo; Owen, Nisha; Jørgensen, Elmer T.; Lewis, Simon L.Agricultural expansion has resulted in both land use and land cover change (LULCC) across the tropics. However, the spatial and temporal patterns of such change and their resulting impacts are poorly understood, particularly for the pre-satellite era. Here we quantify the LULCC history across the 33.9 million ha watershed of Tanzania's Eastern Arc Mountains, using geo-referenced and digitised historical land cover maps (dated 1908, 1923, 1949 and 2000). Our time series from this biodiversity hotspot shows that forest and savanna area both declined, by 74% (2.8 million ha) and 10% (2.9 million ha), respectively, between 1908 and 2000. This vegetation was replaced by a five-fold increase in cropland, from 1.2 million ha to 6.7 million ha. This LULCC implies a committed release of 0.9 Pg C (95% CI: 0.4-1.5) across the watershed for the same period, equivalent to 0.3 Mg C ha−1 yr−1. This is at least three-fold higher than previous estimates from global models for the same study area. We then used the LULCC data from before and after protected area creation, as well as from areas where no protection was established, to analyse the effectiveness of legal protection on land cover change despite the underlying spatial variation in protected areas. We found that, between 1949 and 2000, forest expanded within legally protected areas, resulting in carbon uptake of 4.8 (3.8-5.7) Mg C ha−1, compared to a committed loss of 11.9 (7.2-16.6) Mg C ha−1 within areas lacking such protection. Furthermore, for nine protected areas where LULCC data is available prior to and following establishment, we show that protection reduces deforestation rates by 150% relative to unprotected portions of the watershed. Our results highlight that considerable LULCC occurred prior to the satellite era, thus other data sources are required to better understand long-term land cover trends in the tropics. Discover the world's research 100 million publications 2.5 million new publications each month 10 million members Join for freeItem Quantifying and understanding carbon storage and sequestration within the Eastern Arc Mountains of Tanzania, a tropical biodiversity hotspot(2014-04) Willcock, Simon; Phillips, Oliver L.; Platts, Philip J.; Balmford, Andrew; Burgess, Neil D.; Lovett, Jon C.; Ahrends, Antje; Bayliss, Julian; Doggart, Nike; Doody, Kathryn; Fanning, Eibleis; Green, Jonathan; Hall, Jaclyn; Howell, Kim; Marchant, Rob A.; Marshall, Andrew R.; Mbilinyi, Boniface P.; Munishi, Pantaleo; Owen, Nisha; Swetnam, Ruth D.; Jørgensen, Elmer T.; Lewis, Simon L.Background: The carbon stored in vegetation varies across tropical landscapes due to a complex mix of climatic and edaphic variables, as well as direct human interventions such as deforestation and forest degradation. Mapping and monitoring this variation is essential if policy developments such as REDD+ (Reducing Emissions from Deforestation and Forest Degradation) are to be known to have succeeded or failed. Results: We produce a map of carbon storage across the watershed of the Tanzanian Eastern Arc Mountains (33.9 million ha) using 1,611 forest inventory plots, and correlations with associated climate, soil and disturbance data. As expected, tropical forest stores more carbon per hectare (182 Mg C ha-1) than woody savanna (51 Mg C ha-1). However, woody savanna is the largest aggregate carbon store, with 0.49 Pg C over 9.6 million ha. We estimate the whole landscape stores 1.3 Pg C, significantly higher than most previous estimates for the region. The 95% Confidence Interval for this method (0.9 to 3.2 Pg C) is larger than simpler look-up table methods (1.5 to 1.6 Pg C), suggesting simpler methods may underestimate uncertainty. Using a small number of inventory plots with two censuses (n = 43) to assess changes in carbon storage, and applying the same mapping procedures, we found that carbon storage in the tree-dominated ecosystems has decreased, thItem Towards Regional, Error-Bounded Landscape Carbon Storage Estimates for Data-Deficient Areas of the World(2012-09) Willcock, Simon; Phillips, Oliver L.; Platts, Philip J.; Balmford, Andrew; Burgess, Neil D.; Lovett, Jon C.; Ahrends, Antje; Bayliss, Julian; Doggart, Nike; Doody, Kathryn; Fanning, Eibleis; Green, Jonathan; Hall, Jaclyn; Howell, Kim; Marchant, Rob A.; Marshall, Andrew R.; Mbilinyi, Boniface P.; Munishi, Pantaleo; Owen, Nisha; Swetnam, Ruth D.; Jørgensen, Elmer T.; Lewis, Simon L.Monitoring landscape carbon storage is critical for supporting and validating climate change mitigation policies. These may be aimed at reducing deforestation and degradation, or increasing terrestrial carbon storage at local, regional and global levels. However, due to data-deficiencies, default global carbon storage values for given land cover types such as 'lowland tropical forest' are often used, termed 'Tier 1 type' analyses by the Intergovernmental Panel on Climate Change (IPCC). Such estimates may be erroneous when used at regional scales. Furthermore uncertainty assessments are rarely provided leading to estimates of land cover change carbon fluxes of unknown precision which may undermine efforts to properly evaluate land cover policies aimed at altering land cover dynamics. Here, we present a repeatable method to estimate carbon storage values and associated 95% confidence intervals (CI) for all five IPCC carbon pools (aboveground live carbon, litter, coarse woody debris, belowground live carbon and soil carbon) for data-deficient regions, using a combination of existing inventory data and systematic literature searches, weighted to ensure the final values are regionally specific. The method meets the IPCC 'Tier 2' reporting standard. We use this method to estimate carbon storage over an area of33.9 million hectares of eastern Tanzania, reporting values for 30 land cover types. We estimate that this area stored 6.33 (5.92-6.74) Pg C in the year 2000. Carbon storage estimates for the same study area extracted from five published Africa-wide or global studies show a mean carbon storage value of ∼50% of that reported using our regional values, with four of the five studies reporting lower carbon storage values. This suggests that carbon storage may have been underestimated for this region of Africa. Our study demonstrates the importance of obtaining regionally appropriate carbon storage estimates, and shows how such values can be produced for a relatively low investment. Discover the world's research 100 million publications 2.5 million new publications each month 10 million members Join for free