Systematics and biogeography of amphibians of the African Eastern Arc mountains

Abstract available p. i

A new peat bog testate amoeba transfer function and quantitative palaeohydrological reconstructions from southern Patagonia

Testate amoebae have been extensively used as proxies for environmental change and palaeoclimate reconstructions in European and North American peatlands. The presence of these micro-organisms near the peat surface is generally significantly linked to the local water table depth (WTD) and therefore preservation of the amoeba shells downcore allows for water table reconstructions over millennia. In the last decades, attention for the palaeoecology of the southern Patagonian peat bogs has increased, partly because of the particular climatological setting under the influence of the southern westerlies. These atypical peat bogs are characterised by a wide range of water tables, from wet hollows to hummocks exceeding 100 cm above the water table, and a dominance of Sphagnum magellanicum on low lawns up to the highest hummocks. Here we present the first transfer function for this region that allows for reliable WTD reconstructions, along with 2k-year palaeorecords from local peat bogs.A modern dataset (155 samples) was sampled along transects from five bogs in 2012 and 2013. Measurements of WTD, pH and conductivity were taken for all samples. Transfer function model was based on the 2012 dataset while the 2013 samples served as an independent test set to validate the model. Besides the standard leave-one- out cross-validation we applied leave-one-site-out and leave-one transect-out cross-validation, which are effective means of verifying the degree of clustering in the dataset. To assure the environmental gradient had been evenly sampled we quantified the root-mean-squared error of prediction (RMSEP) individually for segments of this gradient.Ordinations showed a clear hydrological gradient in amoeba assemblages, with the dominant Assulina muscorum at the dry end and Amphitrema wrightianum and Difflugia globulosa at the wet end. Taxa as Nebela certesi and Nebela cockayni, possibly exclusive to the southern hemisphere, were identified and their optima and tolerances were determined. Canonical correspondence analysis showed that WTD was the most important environmental variable, accounting for 18% of the variance in amoeba assemblages. A weighted averaging-partial least squares model showed best performance in cross-validation and using the 2013 data as an independent test set. Any spatial autocorrelation was minimal although the model still appeared less effective in predicting WTD for sites not included in the training set. The segment-wise RMSEP showed that the WTD gradient was generally evenly sampled with RMSEP below 15 cm for most of the gradient, much lower than the standard deviation of the mean of all WTDs (26 cm).Preliminary results from peat cores sampled from the same peat bogs show surprisingly stable water tables over the last 2k years in Andorra bog but more variation in nearby Tierra Australis bog. Peat accumulation rates in Andorra bog are among the highest recorded in temperate bogs with around 4 m of peat accumulated during the last 2000 year

Late-Holocene climate dynamics recorded in the peat bogs of Tierra del Fuego, South America

The ombrotrophic peat bogs of Tierra del Fuego are located within the southern westerly wind belt (SWWB), which dominates climate variability in this region. We have reconstructed late-Holocene water-table depths from three peat bogs and aimed to relate these records to shifts in regional climate. Water-table depths were quantified by the analysis of testate amoeba assemblages, and a regional transfer function was used to infer past water-table depths. During the last 2000 years, testate amoeba assemblages have been relatively stable, with a dominance of Difflugia pulex and Difflugia pristis type, and an increase in Assulina muscorum and other Euglyphida at the top of each section. Multivariate analyses show that water-table depth remained the main environmental variable explaining assemblages along the TiA12 core, but reconstructions were not significant for the two other cores. In line with the low variability in assemblages, water tables were relatively stable during the last 2000 years. Slightly wetter conditions were found between ~1400 and 900 cal. BP and a pronounced recent dry shift was reconstructed in all of the three peat profiles. Considering the regional climatic context, this recent shift may have been forced by a decrease in precipitation and warmer conditions linked to an increase in the importance of the SWWB. Nevertheless, we cannot exclude the influence of higher UV-B radiation resulting from the local degradation of the ozone layer since the late 1970s, which may have had an additional effect on the relative presence of A. muscorum in the southern Patagonian region

An alternative approach to transfer functions? Testing the performance of a functional trait-based model for testate amoebae

publisher: Elsevier articletitle: An alternative approach to transfer functions? Testing the performance of a functional trait-based model for testate amoebae journaltitle: Palaeogeography, Palaeoclimatology, Palaeoecology articlelink: http://dx.doi.org/10.1016/j.palaeo.2016.12.005 content_type: article copyright: © 2016 The Authors. Published by Elsevier B.V

Multi-proxy palaeoclimate reconstructions from peatlands in southern South America

There is a relative paucity of palaeoclimatic archives in South America relative to many other regions of the world. This paucity must be addressed in order to validate climate models and improve our understanding of the global climate system. The southern westerlies represent an important component of climatic variability in the region and, in turn, their migration and changes in their intensity can play a key role in determining whether the Southern Ocean functions as a sink or source of atmospheric carbon dioxide. Increased ventilation of deep waters with elevated concentrations of dissolved inorganic carbon, driven by enhanced Ekman transport, leads to increased outgassing of carbon dioxide. However, as instrumental records are limited to the latter half of the twentieth century, little is known about the long-term variability of the southern Westerlies and their subsequent effects.The Peninsula Brunswick and Isla Grande de Tierra del Fuego are directly situated in the core path of the southern westerlies during the Austral summer and they are ideally suited for studies of past variability in westerly intensity and position. The region’s abundant peatlands are capable of recording these long-term changes, as wind intensity and westerly position affects precipitation and temperature, two key drivers (i.e. P-E) of water-table dynamics in ombrotrophic peatlands. Currently, the peatlands of southern Patagonia represent a relatively unexploited resource in terms of palaeoclimate reconstruction. As a result, we have developed a new regional network of multi-proxy (testate amoebae, plant macrofossils, stable isotopes) archives, supported by high-resolution radiocarbon chronologies, to develop quantitative climate reconstructions for southern South America spanning the last ?2000 years using Sphagnum magellanicum-dominated peat deposits

Herpetofauna of Montane Areas of Tanzania. 4. Amphibians and Reptiles of Mahenge Mountains, with Comments on Biogeography, Diversity, and Conservation

The Mahenge Mountains are located in the Eastern Arc Mountains, part of a global biodiversity hotspot. Few amphibian and reptile surveys have been conducted in this area, with only one study of the submontane forest zone. This previous study revealed a characteristic endemic Eastern Arc amphibian and reptile forest fauna. New studies outlined here extend the sampling time considerably and the geographical coverage (including Mselezi Forest Reserve). These studies reveal a remarkable diversity of amphibians and reptiles increasing known faunal diversity considerably, including several putative new species that await further taxonomic verification. Biogeographical analyses using Bray-Curtis indices show Mahenge clusters with the geographically close Udzungwa Mountains and Southern Highlands (non–Eastern Arc highland fragment including Mt. Rungwe). This clustering of areas suggests an interesting biogeographical history and deserves special attention in the future. In light of the remarkable amphibian and reptile diversity, conservation of Mahenge habitats, in particular Sali Forest Reserve, is desperately required

A new brevicipitid species (Anura: Brevicipitidae: Callulina) from the fragmented forests of the Taita Hills, Kenya

Loader, Simon P., Measey, John, De, Rafael O., Malonza, Patrick K. (2009): A new brevicipitid species (Brevicipitidae: Callulina) from the fragmented forests of the Taita Hills, Kenya. Zootaxa 2123: 55-68, DOI: 10.5281/zenodo.18815