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PubMed | CIFOR, Jardin Botanico Joaquin Antonio Uribe, Red para la Mitigacion y Adaptacion al Cambio Climatico de la UNAD, Herbario Universitario and 63 more.
Type: | Journal: Scientific reports | Year: 2017

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 1ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.


Ahrends A.,Royal Botanic Garden Edinburgh | Ahrends A.,University of York | Rahbek C.,Copenhagen University | Bulling M.T.,University of Aberdeen | And 12 more authors.
Biological Conservation | Year: 2011

Over the last few decades, resources for descriptive taxonomy and biodiversity inventories have substantially declined, and they are also globally unequally distributed. This could result in an overall decline in the quality of biodiversity data as well as geographic biases, reducing the utility and reliability of inventories. We tested this hypothesis with tropical tree records (n = 24,024) collected from the Eastern Arc Mountains, Tanzania, between 1980 and 2007 by 13 botanists, whose collections represent 80% of the total plant records for this region. Our results show that botanists with practical training in tropical plant identification record both more species and more species of conservation concern (20 more species, two more endemic and one more threatened species per 250 specimens) than untrained botanists. Training and the number of person-days in the field explained 96% of the variation in the numbers of species found, and training was the most important predictor for explaining recorded numbers of threatened and endemic species. Data quality was related to available facilities, with good herbarium access significantly reducing the proportions of misidentifications and misspellings. Our analysis suggests that it may be necessary to account for recorder training when comparing diversity across sites, particularly when assessing numbers of rare and endemic species, and for global data portals to provide such information. We also suggest that greater investment in the training of botanists and in the provisioning of good facilities would substantially increase recording efficiency and data reliability, thereby improving conservation planning and implementation on the ground. © 2010 Elsevier Ltd.


Platts P.J.,University of York | Ahrends A.,Royal Botanic Garden Edinburgh | Gereau R.E.,Missouri Botanical Garden | McClean C.J.,University of York | And 6 more authors.
Diversity and Distributions | Year: 2010

Aim: Data shortages mean that conservation priorities can be highly sensitive to historical patterns of exploration. Here, we investigate the potential of regionally focussed species distribution models to elucidate fine-scale patterns of richness, rarity and endemism. Location: Eastern Arc Mountains, Tanzania and Kenya. Methods: Generalized additive models and land cover data are used to estimate the distributions of 452 forest plant taxa (trees, lianas, shrubs and herbs). Presence records from a newly compiled database are regressed against environmental variables in a stepwise multimodel. Estimates of occurrence in forest patches are collated across target groups and analysed alongside inventory-based estimates of conservation priority. Results: Predicted richness is higher than observed richness, with the biggest disparities in regions that have had the least research. North Pare and Nguu in particular are predicted to be more important than the inventory data suggest. Environmental conditions in parts of Nguru could support as many range-restricted and endemic taxa as Uluguru, although realized niches are subject to unknown colonization histories. Concentrations of rare plants are especially high in the Usambaras, a pattern mediated in models by moisture indices, whilst overall richness is better explained by temperature gradients. Tree data dominate the botanical inventory; we find that priorities based on other growth forms might favour the mountains in a different order. Main conclusions: Distribution models can provide conservation planning with high-resolution estimates of richness in well-researched areas, and predictive estimates of conservation importance elsewhere. Spatial and taxonomic biases in the data are essential considerations, as is the spatial scale used for models. We caution that predictive estimates are most uncertain for the species of highest conservation concern, and advocate using models and targeted field assessments iteratively to refine our understanding of which areas should be prioritised for conservation. © 2010 Blackwell Publishing Ltd.


Marshall A.R.,University of York | Marshall A.R.,Flamingo Land Ltd. | Jorgensbye H.I.O.,Copenhagen University | Rovero F.,Tropical Biodiversity | And 4 more authors.
American Journal of Primatology | Year: 2010

This study investigates the species-area relationship (SAR) for forest monkeys in a biodiversity hotspot. The Udzungwa Mountains of Tanzania are well-suited to investigate the SAR, with seven monkey species in a range of fragment sizes (0.06-526 km2). We test the relationship between species richness and forest fragment size, relative to human and environmental factors. We distinguish resident and transitory species because the latter have an "effective patch size" beyond the area of forest. Forest area was the strongest (log-linear) predictor of species richness. However, forest area, elevation range and annual moisture index were intercorrelated. Previous knowledge of the relationship between elevation and tree communities suggests that the SAR is largely a result of habitat heterogeneity. Isolation by farmland (matrix habitat) also had a significant negative effect on species richness, probably exacerbated by hunting in small forests. The effect of area and isolation was less for transitory species. The human influence on species' presence/absence was negatively related to the extent of occurrence. Weaker relationships with temperature and precipitation suggest underlying climatic influences, and give some support for the influence of productivity. A reduced area relationship for smaller forests suggests that fragment sizes below 12-40km2 may not be reliable for determining SAR in forest monkeys. Further practical implications are for management to encourage connectivity, and for future SAR research to consider residency, matrix classification and moisture besides precipitation. © 2009 Wiley-Liss, Inc.


Greve M.,University of Aarhus | Lykke A.M.,University of Aarhus | Fagg C.W.,University of Brasilia | Bogaert J.,University of Liège | And 14 more authors.
Journal of Ecology | Year: 2012

1.It has been proposed that, across broad spatial scales, climatic factors are the main drivers of ecological patterns, while biotic factors are mainly important at local spatial scales. However, few tests of the effect of biotic interactions on broad-scale patterns have been conducted; conclusions about the scale-dependence of the importance of biotic interactions thus seem premature. 2.We developed an extensive database of locality records of one of Africa's most conspicuous groups, the acacias (the genera Senegalia and Vachellia), and used species distribution models (SDMs) to estimate the distribution of all African acacias. 3.African acacias are particularly well adapted against mammalian herbivory; therefore, we hypothesized that browser diversity could be an important driver of acacia richness. Species richness maps for the two genera were created from SDM-generated maps. Ordinary least square (OLS) regressions and, to consider spatial autocorrelation, simultaneous autoregressive (SAR) analyses were used to model richness of the two genera in relation to mammalian browser richness, current environment (including climate), and climate history since the Last Glacial Maximum (LGM). We used variation partitioning to determine what percentage of variation could be explained by these three groups of factors. 4.Both genera showed centres of richness in East Africa and the Limpopo Basin of southern Africa. Browser richness was the best explanatory variable for richness of both genera. Environmental factors explained negligible variation in the richness of Senegalia, but some variation in Vachellia. For both genera, the residuals of the species richness model of one genus also explained much variation in the richness of the other genus, indicating that common factors not considered in the richness analyses here may additionally be driving the richness of both genera. 5.Mechanisms that could generate a correlation between browser and acacia richness are proposed, and differences in the determinants of richness patterns of Senegalia and Vachellia discussed in the light of the two genera's history of colonization of Africa. 6.Synthesis. This is the first study that demonstrates that consumer diversity can influence richness patterns at continental scales and demonstrates that biotic factors can drive richness even at broad spatial scales. This is the first study that demonstrates that consumer diversity can influence richness patterns at continental scales, and demonstrates that biotic factors can drive richness even at broad spatial scales. © 2012 British Ecological Society.


Platts P.J.,University of York | Platts P.J.,University of Cambridge | Burgess N.D.,Copenhagen University | Gereau R.E.,Missouri Botanical Garden | And 7 more authors.
Environmental Conservation | Year: 2011

Ecological regions aggregate habitats with similar biophysical characteristics within well-defined boundaries, providing spatially consistent platforms for monitoring, managing and forecasting the health of interrelated ecosystems. A major obstacle to the implementation of this approach is imprecise and inconsistent boundary placement. For globally important mountain regions such as the Eastern Arc (Tanzania and Kenya), where qualitative definitions of biophysical affinity are well established, rule-based methods for landform classification provide a straightforward solution to ambiguities in region extent. The method presented in this paper encompasses the majority of both contemporary and estimated preclearance forest cover within strict topographical limits. Many of the species here tentatively considered 'near-endemic' could be reclassified as strictly endemic according to the derived boundaries. LandScan and census data show population density inside the ecoregion to be higher than in rural lowlands, and lowland settlement to be most probable within 30 km. This definition should help to align landscape scale conservation strategies in the Eastern Arc and promote new research in areas of predicted, but as yet undocumented, biological importance. Similar methods could work well in other regions where mountain extent is poorly resolved. Spatial data accompany the online version of this article. © 2011 Foundation for Environmental Conservation.


O'Mara M.T.,Smithsonian Tropical Research Institute | O'Mara M.T.,Arizona State University | O'Mara M.T.,Max Planck Institute for Ornithology (Radolfzell) | Hickey C.M.,University of York | Hickey C.M.,Flamingo Land Ltd
Animal Behaviour | Year: 2012

As they grow, young individuals can use both social and individual learning strategies to develop species-typical feeding ecology, and the utility of these strategies may vary phylogenetically and with environmental stability. Focused learning from mothers and other group members is critical in monkeys, with behaviours such as co-feeding playing strong roles in determining postweaning survival. While adult lemurs are capable of social learning, it is unknown how social information is incorporated during the development of feeding or what social learning strategies are used in this process. Here we evaluate the use of social learning behaviours and the potential for social learning in young ringtailed lemurs, Lemur catta, at the Beza Mahafaly Special Reserve, Madagascar. We show that infant and juvenile ringtailed lemurs use basic and generalized stimulus enhancement that occurs through behavioural synchrony with older nearest neighbours. More focused co-feeding occurred at low levels, and many of the social learning behaviours observed in the other social primate taxa were absent. High levels of individual exploration also contributed to learning, evidenced through high dietary diversity in juveniles relative to other group members. Our observations are consistent with the idea that simple social learning rules are responsible for the development of ecological complexity in many generalist vertebrate species, and that more complicated learning behaviours may not be necessary to learn complex and varied diets. © 2012 The Association for the Study of Animal Behaviour.


Shirima D.D.,Sokoine University of Agriculture | Munishi P.K.T.,Sokoine University of Agriculture | Lewis S.L.,University of Leeds | Burgess N.D.,University of Cambridge | And 6 more authors.
African Journal of Ecology | Year: 2011

We determine the aboveground biomass and carbon storage (ABGC) of trees and the herbaceous layer in miombo woodland in the Eastern Arc Mountains (EAM) of Tanzania. In four 1-ha sample plots in Nyanganje and Kitonga Forests, we measured all trees ≥10cm diameter alongside height and wood mass density. The plots contained an average of 20tree speciesha-1 (range 11-29) and 344stemsha-1 (range 281-382) with Shannon diversity values of 1.05 and 1.25, respectively. We weighted nine previously published woody savannah allometric models based on whether: (i) the model was derived from the same geographical region; (ii) the model included tree height/wood mass density in addition to stem diameter; and (iii) sample size was used to fit the model. The weighted mean ABGC storage from the nine models range from 13.5±2 to 29.8±5Mgha-1. Measured ABGC storage in the herbaceous layer, using the wet combustion method, adds 0.55±0.02MgCha-1. Estimates suggest that EAM miombo woodlands store a range of 13-30Mgha-1 of carbon. Although the estimates suggest that miombo woodlands store significant quantities of carbon, caution is required as this is the first estimate based on in situ data. © 2011 Blackwell Publishing Ltd.


Howlett C.,University of Leeds | Marshall A.R.,University of York | Marshall A.R.,Flamingo Land Ltd. | Hughes W.O.H.,University of Leeds
International Journal of Primatology | Year: 2012

A growing body of literature suggests that the ratio between the second and fourth digits of the hands (2D:4D ratio) is associated with exposure to prenatal sex hormones in a variety of animals including primates. Female baboons form dominance hierarchies composed of matrilines of related individuals, and the social mechanisms contributing to the structure of these hierarchies have been well studied. We here investigated the relationship between inferred prenatal androgen effects (PAE) and female rank in a captive troop of Hamadryas baboons (Papio hamadryas) with a typical social structure and three captive groups of chacma baboons (Papio ursinus) made up entirely of unrelated orphans. Low 2D:4D ratios (high inferred PAE) were associated with higher-ranking females and high 2D:4D ratios (low inferred PAE) with lower-ranking females in both focal species. This negative correlation between 2D:4D ratio and rank suggests prenatal androgens are linked with the maintenance of female ranks within matrilines in troops with a natural social structure and to the ranks acquired by orphan females. © 2012 Springer Science+Business Media, LLC.


Marshall A.R.,University of York | Marshall A.R.,Flamingo Land Ltd. | Willcock S.,University of Leeds | Platts P.J.,University of York | And 13 more authors.
Biological Conservation | Year: 2012

Emerging international policy aimed at reducing carbon emissions from deforestation and forest degradation (REDD+) in developing countries, has resulted in numerous studies on above-ground live carbon (AGC) in tropical forests. However, few studies have addressed the relative importance of disturbance, topography, climate, soil and methods for stem measurement, on the estimation of AGC, or the costs of improving AGC estimates by altering sample regimes. We established 18 one hectare plots containing 7201 stems, stratified along forested elevation gradients in Tanzania. We recorded a broad set of physical, climatic and edaphic predictors of AGC and tree stature. AGC estimates using stem diameter, height and wood density, gave a mean value of 174.6tha -1, compared with 229.6tha -1 when height was excluded. Regression models revealed that stems were tallest for a given diameter at mid-elevation (1000-1250m), on south-facing slopes, and without past logging. High AGC was strongly associated with shallow slopes, followed by intermediate elevation, elephant absence, low potential evapotranspiration and low soil pH. Further regression models to investigate the structural habitat features associated with AGC, revealed significant positive influence of basal area, stem density, and height:diameter ratio, rather than the mean wood density of species present. Large stems (≥70cmdbh; 4.6% of stems) contained 52% of AGC in all plots, declining to 36% in lowland plots. We discuss the cost:benefit of different measurements and recommend a tiered approach to AGC monitoring, depending on available resources. AGC assessments in African forests could exclude small stems, but should aim to record disturbance, topography and species. Stem height is vital for AGC estimation and valuation; when excluding height our 55tha -1 over-estimation of AGC would have over-valued the carbon resource by 24% (US$3300ha -1). © 2012 Elsevier Ltd.

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