Papers by Miguel E . Leal
We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates fr... more We report above-ground biomass (AGB), basal area, stem density and wood mass density estimates from 260 sample plots (mean size: 1.2 ha) in intact closed-canopy tropical forests across 12 African countries. Mean AGB is 395.7 Mg dry mass ha-1 (95% CI: 14.3), substantially higher than Amazonian values, with the Congo Basin and contiguous forest region attaining AGB values (429 Mg ha-1) similar to those of Bornean forests, and significantly greater than East or West African forests. AGB therefore appears generally higher in palaeo- compared with neo-tropical forests. However, mean stem density is low (426±11 stems ha-1 greater than or equal to 100 mm diameter) compared with both Amazonian and Bornean forests (cf. approx. 600) and is the signature structural feature of African tropical forests. While spatial autocorrelation complicates analyses, AGB shows a positive relationship with rainfall in the driest nine months of the year, and an opposite association with the wettest three month...
A new species of Dorstenia L. (Moraceae), D. luamensis M.E.Leal, is described from the Luama Wild... more A new species of Dorstenia L. (Moraceae), D. luamensis M.E.Leal, is described from the Luama Wildlife Reserve, west of Lake Tanganyika and north of the town of Kalemie in the eastern part of the Democratic Republic of Congo (DRC). This species is endemic to the region and differs from any of the other species by its fernlike lithophytic habit and lack of latex. A description and illustration of this species is presented here. Dorstenia luamensis M.E.Leal inhabits moist and shady vertical rock faces close to small waterfalls in the forest; the species is distributed in small populations within the type locality, and merits the conservation status of endangered (EN).
forests Above-ground biomass and structure of 260 African tropical
Purpose – In answer to the urgent need to adapt conservation strategies and approaches to climate... more Purpose – In answer to the urgent need to adapt conservation strategies and approaches to climate change, the purpose of this paper is to locate the climatically stable forests in West and Central Africa and to assess whether they overlap with the existing network of protected areas and if not, to prioritize them for protection. Design/methodology/approach – With ongoing global warming, rain forest will survive where locally soil moisture content remains high compensating for the regional drought stress. As a proxy for a soil moisture-driven model, rainfall .2,000 mm, altitude .500 m and strong relief (standard deviation in elevation data pixels) were overlapped in a GIS analysis to locate the climatically stable forest within the present continuous forest of Central Africa and within the degraded forest of West Africa. As a means of verification, the biodiversity was measured in and outside the identified areas in Gabon and Equatorial Guinea as high levels of biodiversity are relat...
Revista De Biologia Tropical, 1994
The leaf anatomy of 14 secondary and 17 primary tree species was studied in a 30 yr old secondary... more The leaf anatomy of 14 secondary and 17 primary tree species was studied in a 30 yr old secondary, montane Quercus forest in the Costa Rican Cordillera de Talamanca. On the average, foliar tissues are thicker in secondary species, due to the high proportion of spongy parenchyma for water storage. In secondary species the mean lamina thickness was 249.5 J.l.m and the mean thicknesses of palisade and spongy parenchyma were 85.8 J.l.m and 133.9 J.l.m, respectively. In primary species the mean lamina thickness was 220.7 J.l.m and the mean thicknesses of palisade and spongy parenchyma were 75.7 J.l.m and 107.9 J.l.m, respectively. TIte non-palisade parenchyma / palisade parenchyma ratio was slightly higher for secondary species. TIte thickness of palisade parenchyma and spongy parenchyma were significantly correlated for both primary and secondary species. Lamina thickness was significantly correlated with thickness of palisade parenchyma and spongy parenchyma for primary species only. L...
Tropical forests are global centres of both biodiversity and carbon storage. Many tropical countr... more Tropical forests are global centres of both biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest diversity-carbon relationship and this remains largely unexplored. Attempts to assess and understand this relationship in tropical forest ecosystems have been hindered by the scarcity of inventories where carbon storage in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of the relationship between carbon storage and tree diversity. We find strongly contrasting variation in diversity and carbon among continents. Thus, on average, African forests have high carbon storage...
Proceedings of the National Academy of Sciences, 2021
The responses of tropical forests to environmental change are critical uncertainties in predictin... more The responses of tropical forests to environmental change are critical uncertainties in predicting the future impacts of climate change. The positive phase of the 2015–2016 El Niño Southern Oscillation resulted in unprecedented heat and low precipitation in the tropics with substantial impacts on the global carbon cycle. The role of African tropical forests is uncertain as their responses to short-term drought and temperature anomalies have yet to be determined using on-the-ground measurements. African tropical forests may be particularly sensitive because they exist in relatively dry conditions compared with Amazonian or Asian forests, or they may be more resistant because of an abundance of drought-adapted species. Here, we report responses of structurally intact old-growth lowland tropical forests inventoried within the African Tropical Rainforest Observatory Network (AfriTRON). We use 100 long-term inventory plots from six countries each measured at least twice prior to and once...
Biological Conservation, 2021
Science, 2020
The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global cl... more The sensitivity of tropical forest carbon to climate is a key uncertainty in predicting global climate change. Although short-term drying and warming are known to affect forests, it is unknown if such effects translate into long-term responses. Here, we analyze 590 permanent plots measured across the tropics to derive the equilibrium climate controls on forest carbon. Maximum temperature is the most important predictor of aboveground biomass (−9.1 megagrams of carbon per hectare per degree Celsius), primarily by reducing woody productivity, and has a greater impact per °C in the hottest forests (>32.2°C). Our results nevertheless reveal greater thermal resilience than observations of short-term variation imply. To realize the long-term climate adaptation potential of tropical forests requires both protecting them and stabilizing Earth’s climate.
Systematics and Geography of Plants, 2001
In this study the possibility of rainforest outside the postulated refuge areas is explored by as... more In this study the possibility of rainforest outside the postulated refuge areas is explored by assessing the presence of rainforest Caesalpinioideae in Lope forest savannah mosaic in Gabon. In this dry area twenty-six tree species of this subfamily were located. Their physiological ability to cope with drought stress and their impossible migration from the nearest postulated refuge area strongly suggests that these species remained in the Lope area during the last ice age. Extrapolating this observation and incorporating all refuge indicator species outside the postulated refuge area, supports the idea that small fragments of forest persisted during the last ice age acting as micro rejugia.
Phytotaxa, 2017
Aframomum ngamikkense, a new species from the Misotshi-Kabogo Massif in the Albertine Rift, Easte... more Aframomum ngamikkense, a new species from the Misotshi-Kabogo Massif in the Albertine Rift, Eastern D.R. Congo, is described and illustrated. It differs from the superficially similar A. pseudostipulare in the shorter and obtuse ligules up to 5 mm long (vs. acute and up to 10 mm long), and the indistinctly 3-lobed apex of the stamen (vs. distinctly 3-lobed).
Scientific reports, Jan 17, 2017
Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries a... more Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable ...
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Papers by Miguel E . Leal