Dynamics and Characterization of Aedes aegypti (L.) (Diptera: Culicidae) Key Breeding Sites

The present study aimed to analyze the dynamics of containers used as breeding sites by Aedes aegypti (L.) in the city of Aracaju, SE, one of the Northeast Brazilian states. A total of three entomological surveys were performed during different precipitation levels. Breeding sites were categorized according to their function into storage, disposable containers, and reusable containers. “Mean number of pupae” and “frequency of each type of breeding site” were the criteria considered to identify key breeding sites. House index and Breteau index were calculated in each survey. A total of 3,647 water reservoirs were found, of which 220 were breeding sites, where 22,880 immature forms were identified. There were no differences in the mean number of larvae of several types of breeding sites and in the number of larvae among surveys. Larval indices showed a reduction in the second visit, but with no effect on adult occurrence when the number of pupae was considered. Key breeding sites resulted from containers used for water storage. The area studied showed conditions favorable to a new epidemic of dengue fever.     

Variation in Aedes aegypti (Diptera: Culicidae) container productivity in a slum and a suburban district of Rio de Janeiro during dry and wet seasons

Seasonal variation in container productivity and infestation levels by Aedes aegypti were evaluated in two areas with distinct levels of urbanization degrees in Rio de Janeiro, a slum and a suburban neighborhood. The four most productive containers can generate up to 90% of total pupae. Large and open-mouthed containers, such as water tanks and metal drums, located outdoors were the most productive in both areas, with up to 47.49% of total Ae. aegypti pupae collected in the shaded sites in the suburban area. Water-tanks were identified as key containers in both areas during both the dry and rainy seasons. Container productivity varied according to seasons and urbanization degree. However, the mean number of pupae per house was higher in the suburban area, but not varied between seasons within each area (P > 0.05). High infestation indexes were observed for both localities, with a house index of 20.5-21.14 in the suburban and of 9.56-11.22 in the urban area. This report gives potential support to a more focused and cost-effective Ae. aegypti control in Rio de Janeiro.     

Methods for Determining the Uncertainty of Population Estimates Derived from Satellite Imagery and Limited Survey Data: A Case Study of Bo City,Sierra Leone

This study demonstrates the use of bootstrap methods to estimate the total population of urban and periurban areas using satellite imagery and limited survey data. We conducted complete household surveys in 20 neighborhoods in the city of Bo, Sierra Leone, which collectively were home to 25,954 persons living in 1,979 residential structures. For five of those twenty sections, we quantized the rooftop areas of structures extracted from satellite images. We used bootstrap statistical methods to estimate the total population of the pooled sections, including the associated uncertainty intervals, as a function of sample size. Evaluations based either on rooftop area per person or on the mean number of occupants per residence both converged on the true population size. We demonstrate with this simulation that demographic surveys of a relatively small proportion of residences can provide a foundation for accurately estimating the total population in conjunction with aerial photographs.     

Spatial distribution of triatomines in domiciles of an urban area of the Brazilian Southeast Region

Reports of triatomine infestation in urban areas have increased. We analysed the spatial distribution of infestation by triatomines in the urban area of Diamantina, in the state of Minas Gerais, Brazil. Triatomines were obtained by community-based entomological surveillance. Spatial patterns of infestation were analysed by Ripley’s K function and Kernel density estimator. Normalised difference vegetation index (NDVI) and land cover derived from satellite imagery were compared between infested and uninfested areas. A total of 140 adults of four species were captured (100 Triatoma vitticeps, 25Panstrongylus geniculatus, 8 Panstrongylus megistus, and 7 Triatoma arthurneivai specimens). In total, 87.9% were captured within domiciles. Infection by trypanosomes was observed in 19.6% of 107 examined insects. The spatial distributions ofT. vitticeps, P. geniculatus, T. arthurneivai, and trypanosome-positive triatomines were clustered, occurring mainly in peripheral areas. NDVI values were statistically higher in areas infested by T. vitticeps and P. geniculatus. Buildings infested by these species were located closer to open fields, whereas infestations of P. megistus andT. arthurneivai were closer to bare soil. Human occupation and modification of natural areas may be involved in triatomine invasion, exposing the population to these vectors.     

Remote sensing of upland vegetation: the potential of high spatial resolution satellite sensors

Aim Traditional methodologies of mapping vegetation, as carried out by ecologists, consist primarily of field surveying or mapping from aerial photography. Previous applications of satellite imagery for this task (e.g. Landsat TM and SPOT HRV) have been unsuccessful, as such imagery proved to have insufficient spatial resolution for mapping vegetation. This paper reports on a study to assess the capabilities of the recently launched remote sensing satellite sensor Ikonos, with improved capabilities, for mapping and monitoring upland vegetation using traditional image classification methods. Location The location is Northumberland National Park, UK. Methods Traditional remote sensing classification methodologies were applied to the Ikonos data and the outputs compared to ground data sets. This enabled an assessment of the value of the improved spatial resolution of satellite imagery for mapping upland vegetation. Post‐classification methods were applied to remove noise and misclassified pixels and to create maps that were more in keeping with the information requirements of the NNPA for current management processes. Results The approach adopted herein for quick and inexpensive land cover mapping was found to be capable of higher accuracy than achieved with previous approaches, highlighting the benefits of remote sensing for providing land cover maps. Main conclusions Ikonos imagery proved to be a useful tool for mapping upland vegetation across large areas and at fine spatial resolution, providing accuracies comparable to traditional mapping methods of ground surveys and aerial photography.     

Comparative efficacy of existing surveillance tools for Aedes aegypti in Western Kenya

All traditional surveillance techniques for Aedes aegypti have been developed for the cosmopolitan domestic subspecies Ae. aegypti aegypti, and not the sylvatic subspecies, Ae. aegypti formosus. The predominant form in Western Kenya is Ae. aegypti formosus that is rarely associated with human habitations but is linked to transmission of sylvatic dengue virus strains. We compared five surveillance methods for their effectiveness in sampling Ae. aegypti formosus with the goal of determining a sustainable surveillance strategy in Kenya. The methods included larval and pupal surveys, oviposition trapping, BG‐Sentinel trapping, resting boxes, and backpack aspirations. Larval and pupal surveys collected the highest number of Ae. aegypti formosus (51.3%), followed by oviposition traps (45.7%), BG‐Sentinel traps (3.0%), and zero collected with either backpack aspiration or resting box collections. No Ae. aegypti formosus larvae or pupae were found indoors. The results indicate that oviposition traps and outdoor larval and pupal surveys were better surveillance methods for Ae. aegypti formosus in Western Kenya.     

Mapping and monitoring of coastal wetlands of Çukurova Delta in the Eastern Mediterranean region

The aim of this research was to link vegetation characteristics, such as spatial and temporal distribution, and environmental variables, with land cover information derived from remotely sensed satellite images of the Eastern Mediterranean coastal wetlands of Turkey. The research method was based on (i) recording land cover characteristics by means of a vegetation indicator, and (ii) classifying and mapping coastal wetlands utilizing a Landsat Thematic Mapper (TM) image of Çukurova Deltas in Turkey. Vegetation characteristics of various habitats, such as sand dunes, salt marshes, salty plains and afforestation areas, were identified by field surveys. A Landsat TM image of 4 July 1993 was pre-processed and then classified using the Maximum Likelihood (ML) algorithm and Artificial Neural Networks (ANN). As a result of this supervised classification, the land cover types were classified with a largest accuracy of 90.2% by ANN. The classified satellite sensor imagery was linked to vegetation and bird census data, which were available through literature in a Geographical Information System (GIS) environment to determine the spatial distribution of plant and bird biodiversity in this coastal wetland. The resulting data provide an important baseline for further investigations such as monitoring, change detections and designing conservation policies in this coastal ecosystem.     

A new forest cover map of continental southeast Asia derived from SPOT‐VEGETATION satellite imagery

Question: Can recent satellite imagery of coarse spatial resolution support forest cover assessment and mapping at the regional level? Location: Continental southeast Asia. Methods: Forest cover mapping was based on digital classification of SPOT4‐VEGETATION satellite images of 1 km spatial resolution from the dry seasons 1998/1999 and 1999/2000. Following a geographical stratification, the spectral clusters were visually assigned to land cover classes. The forest classes were validated by an independent set of maps, derived from interpretation of satellite imagery of high spatial resolution (Landsat TM, 30 m). Forest area estimates from the regional forest cover map were compared to the forest figures of the FAO database. Results: The regional forest cover map displays 12 forest and land cover classes. The mapping of the region's deciduous and fragmented forest cover remained challenging. A high correlation was found between forest area estimates obtained from this map and from the Landsat TM derived maps. The regional and sub‐regional forest area estimates were close to those reported by FAO. Conclusion: SPOT4‐VEGETATION satellite imagery can be used for mapping consistently and uniformly the extent and distribution of the broad forest cover types at the regional scale. The new map can be considered as an update and improvement on existing regional forest cover maps.     

Continental estimates of forest cover and forest cover changes in the dry ecosystems of Africa between 1990 and 2000

Aim

This study provides regional estimates of forest cover in dry African ecoregions and the changes in forest cover that occurred there between 1990 and 2000, using a systematic sample of medium‐resolution satellite imagery which was processed consistently across the continent.

Location

The study area corresponds to the dry forests and woodlands of Africa between the humid forests and the semi‐arid regions. This area covers the Sudanian and Zambezian ecoregions.

Methods

A systematic sample of 1600 Landsat satellite imagery subsets, each 20 km × 20 km in size, were analysed for two reference years: 1990 and 2000. At each sample site and for both years, dense tree cover, open tree cover, other wooded land and other vegetation cover were identified from the analysis of satellite imagery, which comprised multidate segmentation and automatic classification steps followed by visual control by national forestry experts.

Results

Land cover and land‐cover changes were estimated at continental and ecoregion scales and compared with existing pan‐continental, regional and local studies. The overall accuracy of our land‐cover maps was estimated at 87%. Between 1990 and 2000, 3.3 million hectares (Mha) of dense tree cover, 5.8 Mha of open tree cover and 8.9 Mha of other wooded land were lost, with a further 3.9 Mha degraded from dense to open tree cover. These results are substantially lower than the 34 Mha of forest loss reported in the FAO's 2010 Global Forest Resources Assessment for the same period and area.

Main conclusions

Our method generates the first consistent and robust estimates of forest cover and change in dry Africa with known statistical precision at continental and ecoregion scales. These results reduce the uncertainty regarding vegetation cover and its dynamics in these previously poorly studied ecosystems and provide crucial information for both science and environmental policies.     

Linking field-based ecological data with remotely sensed data using a geographic information system in two malaria endemic urban areas of Kenya

BACKGROUND: Remote sensing technology provides detailed spectral and thermal images of the earth's surface from which surrogate ecological indicators of complex processes can be measured. METHODS: Remote sensing data were overlaid onto georeferenced entomological and human ecological data randomly sampled during April and May 2001 in the cities of Kisumu (population asymptotically equal to 320,000) and Malindi (population asymptotically equal to 81,000), Kenya. Grid cells of 270 meters x 270 meters were used to generate spatial sampling units for each city for the collection of entomological and human ecological field-based data. Multispectral Thermal Imager (MTI) satellite data in the visible spectrum at five meter resolution were acquired for Kisumu and Malindi during February and March 2001, respectively. The MTI data were fit and aggregated to the 270 meter x 270 meter grid cells used in field-based sampling using a geographic information system. The normalized difference vegetation index (NDVI) was calculated and scaled from MTI data for selected grid cells. Regression analysis was used to assess associations between NDVI values and entomological and human ecological variables at the grid cell level. RESULTS: Multivariate linear regression showed that as household density increased, mean grid cell NDVI decreased (global F-test = 9.81, df 3,72, P-value = <0.01; adjusted R2 = 0.26). Given household density, the number of potential anopheline larval habitats per grid cell also increased with increasing values of mean grid cell NDVI (global F-test = 14.29, df 3,36, P-value = <0.01; adjusted R2 = 0.51). CONCLUSIONS: NDVI values obtained from MTI data were successfully overlaid onto georeferenced entomological and human ecological data spatially sampled at a scale of 270 meters x 270 meters. Results demonstrate that NDVI at such a scale was sufficient to describe variations in entomological and human ecological parameters across both cities.     

Water Level Flux in Household Containers in Vietnam - A Key Determinant of Aedes aegypti Population Dynamics

We examined changes in the abundance of immature Aedes aegypti at the household and water storage container level during the dry-season (June-July, 2008) in Tri Nguyen village, central Vietnam. We conducted quantitative immature mosquito surveys of 171 containers in the same 41 households, with replacement of samples, every two days during a 29-day period. We developed multi-level mixed effects regression models to investigate container and household variability in pupal abundance. The percentage of houses that were positive for I/II instars, III/IV instars and pupae during any one survey ranged from 19.5-43.9%, 48.8-75.6% and 17.1-53.7%, respectively. The mean numbers of Ae. aegypti pupae per house ranged between 1.9-12.6 over the study period. Estimates of absolute pupal abundance were highly variable over the 29-day period despite relatively stable weather conditions. Most variability in pupal abundance occurred at the container rather than the household level. A key determinant of Ae. aegypti production was the frequent filling of the containers with water, which caused asynchronous hatching of Ae. aegypti eggs and development of cohorts of immatures. We calculated the probability of the water volume of a large container (>500L) increasing or decreasing by ≥20% to be 0.05 and 0.07 per day, respectively, and for small containers (<500L) to be 0.11 and 0.13 per day, respectively. These human water-management behaviors are important determinants of Ae. aegypti production during the dry season. This has implications for choosing a suitable Wolbachia strain for release as it appears that prolonged egg desiccation does not occur in this village.     

Productivity of natural and artificial containers for Aedes polynesiensis and Aedes aegypti in four American Samoan villages

Six mosquito species were identified in a survey of containers associated with 347 households in four villages in American Samoa. Aedes polynesiensis Marks (Diptera: Culicidae) and Aedes aegypti (L) were the most abundant species, representing 57% and 29% of the mosquitoes identified. Culex quinquefasciatus (Say), Culex annulirostris (Skuse), Aedes oceanicus (Belkin) and Toxorhynchites amboinensis (Doleschall) were also found. Aedes aegypti and Ae. polynesiensis showed distinct differences in their use of containers, preferring large and small containers, respectively. By contrast with previous studies, Ae. polynesiensis utilized domestic and natural containers with equal frequency, whereas Ae. aegypti continued to be found predominantly in domestic containers. Only 15% of containers holding immature mosquitoes included pupae and fewer than 10 Aedes spp. pupae were found in most containers with pupae. An estimated 2289 Ae. polynesiensis and 1640 Ae. aegypti pupae were found in 2258 containers. The presence of both species in the same container did not affect the mean density of either species for larvae or pupae. Glass jars, leaf axils, tree holes and seashells produced few Aedes spp. pupae in any of the study villages. Overall, 75% of Ae. polynesiensis pupae were found in buckets, ice-cream containers and tyres, with <7% being produced in natural containers, whereas 82% of Ae. aegypti pupae were found in 44-gallon (US) drums ( approximately 166L), buckets and tyres. Source reduction efforts targeting these container types may yield significant reductions in both Ae. polynesiensis and Ae. aegypti populations in American Samoa.     

Spatial analysis of G.f.fuscipes abundance in Uganda using Poisson and Zero-Inflated Poisson regression models

BackgroundTsetse flies are the major vectors of human trypanosomiasis of the form Trypanosoma brucei rhodesiense and T.b.gambiense. They are widely spread across the sub-Saharan Africa and rendering a lot of challenges to both human and animal health. This stresses effective agricultural production and productivity in Africa. Delimiting the extent and magnitude of tsetse coverage has been a challenge over decades due to limited resources and unsatisfactory technology. In a bid to overcome these limitations, this study attempted to explore modelling skills that can be applied to spatially estimate tsetse abundance in the country using limited tsetse data and a set of remote-sensed environmental variables.MethodologyEntomological data for the period 2008–2018 as used in the model were obtained from various sources and systematically assembled using a structured protocol. Data harmonisation for the purposes of responsiveness and matching was carried out. The key tool for tsetse trapping was itemized as pyramidal trap in many instances and biconical trap in others. Based on the spatially explicit assembled data, we ran two regression models; standard Poisson and Zero-Inflated Poisson (ZIP), to explore the associations between tsetse abundance in Uganda and several environmental and climatic covariates. The covariate data were constituted largely by satellite sensor data in form of meteorological and vegetation surrogates in association with elevation and land cover data. We finally used the Zero-Inflated Poisson (ZIP) regression model to predict tsetse abundance due to its superiority over the standard Poisson after model fitting and testing using the Vuong Non-Nested statistic.ResultsA total of 1,187 tsetse sampling points were identified and considered as representative for the country. The model results indicated the significance and level of responsiveness of each covariate in influencing tsetse abundance across the study area. Woodland vegetation, elevation, temperature, rainfall, and dry season normalised difference vegetation index (NDVI) were important in determining tsetse abundance and spatial distribution at varied scales. The resultant prediction map shows scaled tsetse abundance with estimated fitted numbers ranging from 0 to 59 flies per trap per day (FTD). Tsetse abundance was found to be largest at low elevations, in areas of high vegetative activity, in game parks, forests and shrubs during the dry season. There was very limited responsiveness of selected predictors to tsetse abundance during the wet season, matching the known fact that tsetse disperse most significantly during wet season.ConclusionsA methodology was advanced to enable compilation of entomological data for 10 years, which supported the generation of tsetse abundance maps for Uganda through modelling. Our findings indicate the spatial distribution of the G. f. fuscipes as; low 0–5 FTD (48%), medium 5.1–35 FTD (18%) and high 35.1–60 FTD (34%) grounded on seasonality. This approach, amidst entomological data shortages due to limited resources and absence of expertise, can be adopted to enable mapping of the vector to provide better decision support towards designing and implementing targeted tsetse and tsetse-transmitted African trypanosomiasis control strategies.     

Population dynamics of the immature stages of Aedes aegypti (Diptera: Culicidae), vector of dengue: a longitudinal study (1996-2000)

A four year study was conducted on a natural population of immature stages of Aedes aegypti after the re-invasion of Argentina by this vector in 1987. Thirty six plastic containers with 700 ml of dechlorinated water were placed in the La Plata Zoological Garden, La Plata, Argentina. A strip of filter paper around each container was added to facilitate egg counting. Eggs, larvae and pupae were counted weekly in each container from September, 1996 to August, 2000. After egg counting, papers were submerged to facilitate egg hatching and a new paper was placed in each container. Presence of A. aegypti immature stages was recorded from December-January to June during each of the four years of this study. In 1997, 13,105 eggs, 7,978 larvae and 1,476 pupae were registered with 54.7 % positive containers; during 1998, 8,194 eggs, 668 larvae and 142 pupae were recorded with 28.3 % positive containers; 13,510 eggs, 3,690 larvae and 743 pupae were registered during 1999 with 56.7 % positive containers; and 16,327 eggs, 4,669 larvae and 715 pupae during 2000 with 59.3 % of containers with presence of A. aegypti. Egg number and hatching rate were drastically reduced in 1998 when temperatures from December to May were 1 to 2.5 degrees C lower than the other years of this study. These colder than usual temperatures in the summer of 1998 were a consequence of the El Ni?o event.     

High-Resolution Satellite Imagery Is an Important yet Underutilized Resource in Conservation Biology

Technological advances and increasing availability of high-resolution satellite imagery offer the potential for more accurate land cover classifications and pattern analyses, which could greatly improve the detection and quantification of land cover change for conservation. Such remotely-sensed products, however, are often expensive and difficult to acquire, which prohibits or reduces their use. We tested whether imagery of high spatial resolution (≤5 m) differs from lower-resolution imagery (≥30 m) in performance and extent of use for conservation applications. To assess performance, we classified land cover in a heterogeneous region of Interior Atlantic Forest in Paraguay, which has undergone recent and dramatic human-induced habitat loss and fragmentation. We used 4 m multispectral IKONOS and 30 m multispectral Landsat imagery and determined the extent to which resolution influenced the delineation of land cover classes and patch-level metrics. Higher-resolution imagery more accurately delineated cover classes, identified smaller patches, retained patch shape, and detected narrower, linear patches. To assess extent of use, we surveyed three conservation journals (Biological Conservation, Biotropica, Conservation Biology) and found limited application of high-resolution imagery in research, with only 26.8% of land cover studies analyzing satellite imagery, and of these studies only 10.4% used imagery ≤5 m resolution. Our results suggest that high-resolution imagery is warranted yet under-utilized in conservation research, but is needed to adequately monitor and evaluate forest loss and conversion, and to delineate potentially important stepping-stone fragments that may serve as corridors in a human-modified landscape. Greater access to low-cost, multiband, high-resolution satellite imagery would therefore greatly facilitate conservation management and decision-making.     

Epidemiology of Plasmodium malariae infection in Gambela, Ethiopia

Malaria incidence and prevalence surveys were performed from December, 1967 to February, 1969 among the indigenous Nilotic inhabitants of Gambela, a small administrative centre in the western lowlands of Ethiopia. Entomological data suggested that malaria transmission was seasonal and this was consistent with monthly P. falciparum parasite rates. Monthly P. malariae parasite rates, however, were consistent with an hypothesis of homogeneity. The age-specific incidence of quartan malaria among 26 children zero to 11 years old at the start of study was examined at 28 day intervals over a 15-month period. The resulting data suggested that parasite acquisition was a slow process and an annual P. malariae incidence of 0.17 was derived. This statistic was supported by studies performed five years later: The incidence of P. malariae among 102 infants followed from birth up to 48 months of age was 0.16-0.20. An attempt was then made to account for the prevalence of P. malariae in terms of the entomological conditions observed in Gambela. Macdonald's formula for the sporozoite rate was used to derive hypothetical relative proportions of P. falciparum and P. malariae among the observed sporozoite-positive mosquito populations. About 4% of the sporozoite challenges were estimated to be of P. malariae. An hypothetical annual entomological P. malariae inoculation rate was then made by multiplying the number of observed sporozoite inoculations per person (approximately 10/year) by the proportion of them estimated to be of P. malariae. The annual P. malariae sporozoite challenge was thus estimated at 0.4 per person, in good agreement with the annual incidence estimates from parasite rates in children.     

Larvicidal and repellent potential of Albizzia amara Boivin and Ocimum basilicum Linn against dengue vector, Aedes aegypti (Insecta:Diptera:Culicidae)

Investigations were made to test the larval toxicity and smoke repellent potential of Albizzia amara and Ocimum basilicum at different concentration (2%, 4%, 6%, 8% and 10%) against the different instar (I, II, III and IV) larvae and pupae of Aedes aegypti. The LC50 values of A. amara and O. basilicum for I instar larvae was 5.412 and 3.734, II instar 6.480 and 4.154, III instar 7.106 and 4.664, IV instar 7.515 and 5.124, respectively. The LC50 and LC90 values of pupae were 6.792%, 5.449% and 16.925%, 15.474%. The smoke toxicity of A. amara was more effective against A. aegypti than the O. basilicum.     

Estimates of tree canopy loss as a result of Cyclone Monica,in the Magela Creek catchment northern Australia

Abstract Severe tropical Cyclone Monica impacted the coast of northern Australia in April 2006 with estimated maximum wind gusts of 360 km h^?1. It rapidly moved inland losing intensity and passed over the town of Jabiru as a category 2 system, with maximum wind gusts recorded at 135 km h^?1. The cyclone had a significant impact on the landscapes within the Alligator Rivers Region and significant windthrow of trees occurred. This paper describes the level of impact that category 2 level winds had on tree canopy loss 10 days after cyclone and then again 1 year later. Recovery was assessed using multispectral satellite imagery in sub‐catchments of the Magela Creek catchments. A non‐linear relationship was fitted between a modified vegetation index (derived from Landsat TM5 satellite data) and percentage tree canopy cover (measured from very high resolution QuickBird satellite data). The results of the non‐linear relationship, used to estimate percentage canopy cover, indicate that 10 days after cyclone, there was significant disturbance to tree canopy. However, data 1 year after cyclone show that recovery of canopy across the studied catchments varied between 8% and 19% of the percentage canopy cover that remained after the initial impact of the cyclone. Further analysis in the three sub‐catchments using Geographical Information System showed that proportionally, riparian zones and inundated areas in each of the sub‐catchments suffered greater loss of tree canopy cover compared with upland areas.     

Decadienal afforestation and risks to montane grassland amphibians in the Udzungwa Plateau,Tanzania

Human modification of the environment has drastically changed ecosystems around the globe. While forest-loss (deforestation) has been well studied for its effects on ecosystems, afforestation also has major impacts. The Udzungwa Plateau in Tanzania is naturally a mix of forests and grasslands. However, non-native pine plantations have recently increased in the area displacing the native grasslands of the montane plateau. In this study, we explored the effects of land use change on amphibian communities by comparing amphibian surveys before non-native plantations were introduced (~2000) and after (2017–2019). To put these amphibian surveys into wider context across the plateau and to distinguish local population loss compared to plateau-wide extinctions, we sample diversity at new sampling locations and locations with multiple surveys through time. We then assessed landscape change through remotely sensed data and ground surveys. Amphibian encounter surveys found approximately the same species diversity across all sampling locations, but local extinctions appear likely. Remaining amphibians appear to be limited to small refugia in non-pine wetlands. Approximately half (45%) of the species found have limited distributional ranges (<72,000 km²) and are described as habitat specialists by the IUCN Red List. Monitoring pine plantation growth using remote sensing techniques suggested only limited extensions of plantations between 2000 through to 2013–2016, but ground surveys found small pines (<3 years old) throughout almost all areas identified as grasslands on satellite imagery. Our study highlights the plight of this narrowing biome on the African continent and calls for more research on the impact of non-native plantations on natural communities. Abstract in Swahili is available with online material.