Detecting and predicting forest degradation: A comparison of ground surveys and remote sensing in Tanzanian forests

Summary • Tropical forest degradation is widely recognised as a driver of biodiversity loss and a major source of carbon emissions. However, in contrast to deforestation, the more gradual changes from degradation are challenging to detect, quantify, and monitor. Here we present a field protocol for rapid, area-standardised quantifications of forest condition, which can also be done by non-specialists. Using the example of threatened high-biodiversity forests in Tanzania, we analyse and predict degradation based on this method. We also compare the field data to optical and radar remote sensing datasets, thereby conducting a large-scale, independent test of the ability of these products to map degradation in East Africa from space. • Our field data consist of 551 ‘degradation’ transects collected between 1996 and 2010, covering >600 ha across 86 forests in the Eastern Arc Mountains and coastal forests. • Degradation was widespread, with over one third of the study forests – mostly protected areas – having more than 10% of their trees cut. Commonly-used optical remote-sensing maps of complete tree cover loss only detected severe impacts (≥25% of trees cut), i.e. a focus on remotely sensed deforestation would have significantly underestimated carbon emissions and declines in forest quality. Radar-based maps detected even low impacts (<5% of trees cut) in ~90% of cases. The field data additionally allowed to differentiate different types and drivers of harvesting, with spatial patterns suggesting that logging and charcoal production were mainly driven by demand from major cities. • Rapid degradation surveys and radar remote sensing can provide an early warning and guide appropriate conservation and policy responses. This is particularly important in areas where forest degradation is more widespread than deforestation, such as in east and southern Africa

Performance of the LHCb RICH photo-detectors and readout in a system test using charged particles from a 25 ns-structured beam

a b s t r a c t The LHCb experiment at the CERN Large Hadron Collider (LHC) utilises two Ring Imaging CHerenkov (RICH) detectors for particle identification. To verify that the RICH assembly will perform as expected prior to installation, an array of 48 production Hybrid Photon Detectors and their readout have been tested under realistic running conditions in a 25 ns-structured charged particle beam provided by the SPS facility at CERN. This system test is an important milestone in the overall commissioning of the LHCb detector and demonstrates that all aspects meet the stringent physics requirements of the LHCb experiment

Quantifying the response of tree hyraxes (Dendrohyrax validus) to human disturbance in the Udzungwa Mountains, Tanzania

Quantifying the effects of human disturbance on rare species is crucial for conservation. The eastern tree hyrax (Dendrohyrax validus), restricted to East Africa, is one of the region’s least studied mammals. This study assesses the effect of hunting and logging on density and calling behavior. We evaluate three methods for estimating relative density: circular plot counts of calling individuals, latrine counts, and daytime transect counts. Circular plots show that the density of calling individuals within one forest is positively related to canopy cover. Furthermore we estimate densities of 17.3 calling individuals ha-1 in a little-disturbed forest, 12.1 in a lightly disturbed forest, and zero in an intensely hunted and formerly logged forest. Other methods support this trend, thus confirming that D. validus is dependent on intact forest. Estimation of hyrax density (and relative density) is however highly problematic and the magnitude of the trend varied between methods. Despite methodological problems, the results clearly highlight the discordance between Forest Reserve legislation and management, a conservation concern throughout the tropics

Relative densities of mammals in response to different levels of bushmeat hunting in the Udzungwa Mountains, Tanzania

Bushmeat hunting constitutes the most immediate threat to wildlife populations in the Udzungwa Mountains of the Eastern Afromontane biodiversity hotspot. This study assesses the impact of hunting by comparing densities of mammalian species between the little hunted West Kilombero Scarp Forest Reserve (WKSFR), the medium-hunted Udzungwa Scarp Forest Reserve (USFR) and the intensively hunted New Dabaga Ulangambi Forest Reserve (NDUFR). Of the 22 species recorded, 20 were present in WKSFR, 17 in USFR and 12 in NDUFR. Most large species (>40 kg.) were absent from hunted areas, while medium-sized species were reduced more than smaller species. Few traces of Abbot’s duiker were observed in hunted areas and bush pig was reduced below 85% in hunted areas. Hunting appears to have little effect on primates, blue duiker, Harvey’s duiker, aardvark, eastern tree hyrax, and giant pouched rat in USFR, while hunting in NDUFR only seems of less concern for primates and giant pouched rat. Thus, the effect of hunting appears to be proportional to the size of the species and the intensity of hunting, although effects of life history strategy, forest fragment size, isolation, and previous logging cannot be excluded. Reductions of hunting levels are paramount to the survival of large bodied species in USFR and for the continued presence of most species in NDUFR. This study furthermore constitutes an important baseline for monitoring the effect of current efforts to implement joint forest management in the Udzungwa Mountains

Proposal for multi-anode photo multiplier tubes as photo detectors for the LHCb RICH

We propose to use the Multianode Photo Multiplier Tubes (MAPMT) as the photosensitive device for the Ring Imaging Cherenkov (RICH) detector in the LHCb experiment. We demonstrate that MAPMT meet the specifications which are required to perform excellent particle identification of charged tracks over the full acceptance. A baseline design is presented. At the end of 1999 the MAPMT has been selected as backup choice for the photodetectors. We present the implication of this decision on the baseline design

Performance of the LHCb RICH photodetectors in a charged particle beam

The Ring Imaging Cherenkov detectors of LHCb will use pixel Hybrid Photon Detectors to measure the spatial position of Cherenkov photons. The first six pre-production photon detectors have been tested in a beam, together with prototypes of the on-detector electronics. The tests were performed at CERN using 10 GeV / c pions together with an N2 gas radiator as a source of Cherenkov light. With 1.1 m of radiator, around 10 photoelectrons were detected per track. The single-photon Cherenkov angle resolution was measured to be 1.66 ± 0.03 mrad, which is dominated by the pixelisation of the photon detector in the test-beam set-up. Both numbers agree with expectations. © 2007 Elsevier B.V. All rights reserved

Performance of the LHCb RICH photo-detectors and readout in a system test using charged particles from a 25 ns-structured beam

The LHCb experiment at the CERN Large Hadron Collider (LHC) utilises two Ring Imaging CHerenkov (RICH) detectors for particle identification. To verify that the RICH assembly will perform as expected prior to installation, an array of 48 production Hybrid Photon Detectors and their readout have been tested under realistic running conditions in a 25 ns-structured charged particle beam provided by the SPS facility at CERN. This system test is an important milestone in the overall commissioning of the LHCb detector and demonstrates that all aspects meet the stringent physics requirements of the LHCb experiment. © 2009 Elsevier B.V