Tropical Landscapes Research Articles

Forest cover modulates diversity and morphological traits of ants in highly fragmented tropical forest landscapes

Forest cover modulates diversity and morphological traits of ants in highly fragmented tropical forest landscapes

Lightly-harvested rustic cocoa is a valuable land cover for amphibian and reptile conservation in human-modified rainforest landscapes

AbstractThe conservation of tropical biodiversity depends not only on forest remnants, but also on anthropogenic land covers. Some shade crops are considered wildlife-friendly agroecosystems, but their conservation value is context- and taxon-dependent. Amphibians and reptiles have received less attention despite their high sensitivity to habitat disturbance. We determined the conservation value of lightly-harvested rustic cocoa plantations for herpetofauna in the Lacandona region, Mexico. We compared 12 environmental variables between habitats. Then, we compared the abundance, species number and composition of amphibian and reptile assemblages. Within each habitat, we explored the relationships between environmental variables and abundance and species number. Tree density, litter cover and litter depth were higher in cocoa. Abundance of reptiles and amphibians were higher in cocoa than forest; species number did not differ. Habitat explained some of the variation (8%) in assemblage composition. In cocoa, amphibian abundance was positively related to canopy height and the presence of a humus layer, while reptile abundance was negatively related to relative humidity. We conclude that lightly-used rustic cocoa plantations can be suitable habitat for forest herpetofauna. As long as cocoa plantations do not replace existing forest cover, they can play an important role in the design of wildlife-friendly tropical landscapes.

Native tree species richness enhances matrix functionality for soil arthropods in tropical plantation landscapes: A case study from the Himalayas

AbstractDespite their distinctive role in regulating agroecosystems, soil fauna is largely excluded from conservation action. With increasing evidence supporting matrix functionality as critical for multiple species in agroecosystems, it is important that efforts meant to enhance biodiversity in managed systems be inclusive and effective for all species and not just charismatic fauna.Third party certifications are a popular mechanism for claiming pro‐conservation practises in tropical agricultural lands. Therefore, we asked whether voluntary practises codified by third party certifications of tropical tea plantations support soil biodiversity, and what factors explain soil arthropod abundance and richness in such certified and uncertified landscapes.We used pitfall trap data and soil samples across two seasons in large tea plantations, and small tea‐growing agroforestry farms in the Darjeeling Himalayas in India. Plantations certified and those not certified were selected for the study.Soil arthropod morphospecies abundance, richness and diversity were significantly higher in summer as opposed to winter. Contrary to our expectations, there was no significant difference in soil arthropod abundance, richness and diversity between uncertified small agroforestry farms and certified large monoculture plantations. Our analysis establishes tree species richness and season as the most important predictors of soil arthropod abundance, richness and effective number of species.We recommend that increased abundance and diversity of native trees in the tea matrix should be a crucial criterion for agroecosystem management. This would improve matrix functionality for species that are sensitive to management and reflect practises that enhance biodiversity.

Dung beetles maintain phylogenetic divergence but functional convergence across a highly fragmented tropical landscape

Abstract Understanding how human‐modified landscapes affect the phylogenetic composition and assembly mechanisms of biological communities is critical for effectively managing and restoring tropical ecosystems. We evaluated how forest coverage loss, fragmentation and landscape heterogeneity affect the phylogenetic diversity of dung beetles and their assembly mechanisms in Los Tuxtlas Biosphere Reserve, a protected but highly fragmented tropical landscape. We calculated Faith's phylogenetic diversity, mean pairwise phylogenetic distance and mean nearest taxon distance for 5,388 individuals in 36 species. The standardised effect sizes of these metrics were estimated to control their correlation with species richness. Phylogenetic diversity was also assessed separately for each dung beetle functional group. Finally, we compared the mean functional and phylogenetic pairwise distance and mean nearest taxon distance and measured the phylogenetic signal among dung beetle functional traits to determine the influence of niche conservatism on the phylogenetic structure of species assemblages. Faith's phylogenetic diversity of dung beetles was positively correlated with forest coverage, while their mean phylogenetic and nearest taxon distance values decreased with increasing landscape fragmentation. Necrophagous beetles and forest specialists responded most negatively to forest coverage loss and fragmentation. Alpha and beta diversity values showed phylogenetic overdispersion but functional convergence and weak phylogenetic signals in their functional traits, suggesting low niche conservatism. Landscapes with moderate forest coverage (≥40%) favoured higher phylogenetic beta diversity, whereas phylogenetic and functional beta diversity decreased significantly in landscapes with low forest coverage (<30%). Synthesis and applications. Forest habitats in fragmented landscapes are essential for safeguarding the evolutionary history of dung beetles, reducing biotic homogenisation processes by favouring phylogenetic overdispersion and complementarity between sites. Therefore, to secure the phylogenetic diversity of dung beetles within fragmented tropical reserves, we recommend protecting the existing forests, preventing further fragmentation of continuous forest areas and increasing matrix quality by implementing biodiversity‐friendly production systems. Finally, managers should consider assessing different functional groups in other species, as their response to landscape disturbance may not be phylogenetically similar. The above will allow more effective management practices to protect the species most susceptible to disturbances.

Linking regeneration niche to monodominance in biodiverse tropical forest landscapes

AbstractAimsAlthough monodominance has attracted the attention of ecologists for many decades, few studies have devoted attention to how abiotic factors could influence the occurrence of monodominant forest patches at the biome scale. Here, we assessed whether the occurrence of monodominant forest patches of Moquiniastrum polymorphum (Less.) G. Sancho (Asteraceae), an early‐successional tree species with wind‐dispersed seeds, could be predicted using optimum germination temperature and past deforestation. We also verified under what edaphic and climatic conditions the species could reach monodominance.LocationThe Atlantic Forest, Brazil.MethodsWe estimated optimum germination temperature across the species’ geographic range as a function of annual mean temperature based on the results of germination tests available in the literature. Past deforestation (a proxy for suitable habitat for the species’ dispersal and establishment) around monodominant forest patches was estimated by calculating the forest cover in 1985. We also modeled the upper limit of dominance (relative abundance) as a function of climatic and edaphic variables considered important for the species’ establishment.ResultsThe results showed that the probability of occurrence of monodominant forest patches is statistically null in places where germination can take more than 10 days and the landscape had more than 20% forest cover. Relative density values for the monodominant condition (> 60%) occurred only in warmer regions with infertile soils and median precipitation conditions (ca. 1,075–1,700 mm per year) in the Atlantic Forest.ConclusionWe conclude that only under optimal conditions of germination and dispersal (i.e., regeneration niche) does monodominance occur. This highlights germination traits as an important mechanism for regulating monodominance. In addition, the approach used to predict regions with optimum germination temperature has further implications for understanding species abundance and distribution more generally.

Spatiotemporal analysis of deforestation patterns and drivers reveals emergent threats to tropical forest landscapes

As deforestation breaches into new tropical frontiers, proactive conservation strategies require a trifecta of information on where deforestation is accelerating (emergent), how drivers of deforestation vary spatiotemporally, and where to focus limited conservation resources in protecting the most integral yet threatened forested landscapes. Here we introduce Emergent Threat Analysis, a process integrating Emerging Hot Spot Analysis of deforestation, visual classification of deforestation outcomes over time, and spatial quantification of contemporary forest condition. We applied Emergent Threat Analysis to tropical Southeast Asia, a global epicentre of biodiversity threatened by deforestation. We found that emergent hot spots (EHS)—a subset of hot spots characterized by strong, recent, and clustered patterns of deforestation—accounted for 26.1% of total forest loss from 1992 to 2018, with deforestation within EHS proceeding at 2.5 times the regional rate of gross loss. Oil palm and rubber plantation expansion were the principal drivers of deforestation within EHS of insular and mainland SE Asia, respectively. Over the study period, oil palm shifted in importance from Sumatra and Sarawak to Papua and Kalimantan, whereas rubber became prominent in Cambodia and Tanintharyi from 2006 to 2015. As of 2019, more than 170 000 km2 of SE Asia’s remaining forest occurred within EHS, of which 21.7% was protected. High and medium-integrity forest constituted 19.2% and 49.1% of remaining EHS forest, respectively, but of these, 35.0% of high-integrity and 23.9% of medium-integrity EHS forest were protected. Because we anticipate that tree plantation expansion will continue to drive deforestation in SE Asia, significantly heightened protection is needed to secure the long-term preservation of high and medium-integrity forest, especially in highly contested forest frontier regions. Finally, as a flexible, integrated process, Emergent Threat Analysis is applicable to deforestation fronts across the global tropics.

Species-level tree crown maps improve predictions of tree recruit abundance in a tropical landscape.

Predicting forest recovery at landscape scales will aid forest restoration efforts. The first step in successful forest recovery is tree recruitment. Forecasts of tree recruit abundance, derived from the landscape-scale distribution of seed sources (i.e., adult trees), could assist efforts to identify sites with high potential for natural regeneration. However, previous work revealed wide variation in the effect of seed sources on seedling abundance, from positive to no effect. We quantified the relationship between adult tree seed sources and tree recruits and predicted where natural recruitment would occur in a fragmented, tropical, agricultural landscape. We integrated species-specific tree crown maps generated from hyperspectral imagery and property ownership data with field data on the spatial distribution of tree recruits from five species. We then developed hierarchical Bayesian models to predict landscape-scale recruit abundance. Our models revealed that species-specific maps of tree crowns improved recruit abundance predictions. Conspecific crown area had a much stronger impact on recruitment abundance (8.00% increase in recruit abundance when conspecific tree density increases from zero to one tree; 95% credible interval (CI): 0.80% to 11.57%) than heterospecific crown area (0.03% increase with the addition of a single heterospecific tree, 95% CI: -0.60% to 0.68%). Individual property ownership was also an important predictor of recruit abundance: The best performing model had varying effects of conspecific and heterospecific crown area on recruit abundance, depending on individual property ownership. We demonstrate how novel remote sensing approaches and cadastral data can be used to generate high-resolution and landscape-level maps of tree recruit abundance. Spatial models parameterized with field, cadastral, and remote sensing data are poised to assist decision support for forest landscape restoration.

Predicting landscape-scale biodiversity recovery by natural tropical forest regrowth.

Natural forest regrowth is a cost-effective, nature-based solution for biodiversity recovery, yet different socioenvironmental factors can lead to variable outcomes. A critical knowledge gap in forest restoration planning is how to predict where natural forest regrowth is likely to lead to high levels of biodiversity recovery, which is an indicator of conservation value and the potential provisioning of diverse ecosystem services. We sought to predict and map landscape-scale recovery of species richness and total abundance of vertebrates, invertebrates, and plants in tropical and subtropical second-growth forests to inform spatial restoration planning. First, we conducted a global meta-analysis to quantify the extent to which recovery of species richness and total abundance in second-growth forests deviated from biodiversity values in reference old-growth forests in the same landscape. Second, we employed a machine-learning algorithm and a comprehensive set of socioenvironmental factors to spatially predict landscape-scale deviation and map it. Models explained on average 34% of observed variance in recovery (range 9-51%). Landscape-scale biodiversity recovery in second-growth forests was spatially predicted based on socioenvironmental landscape factors (human demography, land use and cover, anthropogenic and natural disturbance, ecosystem productivity, and topography and soil chemistry); was significantly higher for species richness than for total abundance for vertebrates (median range-adjusted predicted deviation 0.09 vs. 0.34) and invertebrates (0.2 vs. 0.35) but not for plants (which showed a similar recovery for both metrics [0.24 vs. 0.25]); and was positively correlated for total abundance of plant and vertebrate species (Pearson r = 0.45, p = 0.001). Our approach can help identify tropical and subtropical forest landscapes with high potential for biodiversity recovery through natural forest regrowth.

Chronic anthropogenic disturbances and aridity negatively affect specialized reproductive traits and strategies of edible fruit plant assemblages in a Caatinga dry forest

Chronic anthropogenic disturbances and climate change are the main threats to biodiversity, acting as potential drivers of assembly reorganization in human-modified tropical landscapes. We aimed to understand how the reproductive traits of edible fruit plant assemblages respond to chronic disturbances and aridity in the Caatinga, a dry forest in northeastern Brazil housing a human population that greatly depends on natural resources for subsistence and is threatened by increasing aridity. The study was carried out across 20 permanent plots of Caatinga, covering gradients of chronic disturbances (livestock grazing, wood extraction and non-timber product exploitation) and aridity (1051 mm to 664 mm). We registered 24 native plant species with fruits that are edible for humans, which were classified according to their flowering/fruiting pattern, floral size and reward, sexual and reproductive systems, pollination systems, and fruit types. They were also grouped into two categories of reproductive strategies (generalists and specialists). We documented that chronic disturbances and aridity pose more negative than positive effects on the reproductive traits of edible fruit plants in terms of trait richness (negative: 29% of the traits; positive: 3.2%) and abundance (negative: 19.3%; positive: 3.2%). In general, we observed that 79.2% of the studied species had at least one reproductive trait that was negatively reduced by increased chronic disturbance and/or aridity in terms of trait richness and abundance. Overall, 75% of the edible fruit species have specialized reproductive strategies that were negatively affected by chronic disturbances and/or aridity. Specifically, individual or combined effects of chronic anthropogenic disturbances or aridity negatively impacted the richness and abundance of specialized reproductive traits such as supra-annual flowering and fruiting patterns and obligatory cross-pollinated edible fruit species. Also, in terms of richness, the reproductive functional diversity of specialized reproductive strategies was negatively affected by increasing aridity. Our findings indicate that in the expected future scenarios of increased land-use and climate change, the Caatinga could face a collapse in the offer of edible fruits to local human communities by impacting the provision of this ecosystem service.

Dynamics of Anthropogenic Wildfire on Babeldaob Island (Palau) as Revealed by Fire History

Wildfire is an understudied threat to biodiversity in many tropical landscapes, including island nations of the Pacific, such as The Republic of Palau—a global biodiversity hotspot with ridge-to-reef resources. Fires are known to occur on Palau’s main island of Babeldaob, where they can result in increased erosion rates and sediment delivery to near-shore areas with impacts to streams and coral reefs. Fire-adapted native plant species are found in savanna habitats, but fires often extend into adjacent forest areas where they kill overstory trees. To assess this serious biodiversity and human health threat, we mapped wildland fires on Babeldaob Island using ground-based surveys and aerial photographs between 2012 and 2015, and satellite imagery between 2012 and 2021. Data on causal factors, vegetation type, and the presence of invasive species were collected between 2012 and 2015, with hunting, arson, and agricultural clearing being the principal causes of ignitions. Wildfires occurred in all months and in all 10 states of Babeldaob, and both numbers of wildfires and total burned area were substantially greater during dry seasons, with the highest totals occurring in the one El Niño drought year in our record. Overall, wildfires appear to have a minor impact on forest vegetation because they are largely confined to savanna systems, but rainfall on burned savanna is a major cause of erosion and the sedimentation of streams and near-shore habitats.

Effects of nest site selection and nest concealment on nest survival of Gosling's Bunting (Emberiza goslingi)

Selecting nest sites that provide access to resources and reduce predation risk is crucial to maximizing fitness in breeding birds. Therefore, understanding what habitat features influence nest site selection and nest success is a key component of avian conservation because it allows for identification and protection of habitat that will promote population growth. We examined drivers of nest success in Gosling's Bunting (Emberiza goslingi) by evaluating variables that influence nest site choice and nest survival at 23 nests and an equal number of random, paired, non-nesting locations in a tropical savannah landscape in north-central Nigeria. Gosling's Buntings exhibited a nonrandom nest-placement pattern. Nests were either on or in proximity to large rock surfaces with nesting probability increasing when the immediate nesting area (100 m radius around the nest) consisted of 30–60% bare rock. Compared to random non-nesting sites, buntings selected areas that were low in litter cover and/or had short grass height. Daily nest survival probability was high (0.96) and was positively associated with the proportion of bare rock around the nest but negatively with the amount of litter cover. Although hatching success was 56.9%, only 30% of all nesting attempts successfully fledged a chick suggesting that nest failure occurred mostly at advanced stages of nesting (nestling phase) when renesting is less likely. Nest survival was higher at low concealment, but only significantly higher than nest failure within a restricted concealment range of 45–54%. Our findings show that microhabitat features could benefit reproduction and daily nest survival. Furthermore, by linking nest-site attributes with fitness indices, we highlight the potential importance of fitness measures as a key component of habitat quality assessment for these buntings in tropical savannahs.

A Preacher’s Perspective

AbstractThis article presents a critical, postcolonial analysis of the travel accounts of the Dutch church minister Sytze Roorda van Eysinga (1773–1829), who travelled within the East Indies archipelago in the 1820s as ‘visitator’ of the churches and schools in the colony. Which elements are characteristic of the preacher’s perspective? What did he emphasize in his travel texts? How did he represent the indigenous people who had to be Christianized eventually? So far, only little attention has been paid to the preacher’s perspective in general and to the work of Sytze Roorda van Eysinga in particular. First, Roorda’s representation of the tropical landscape is analysed. Then, his ideas about the indigenous people are discussed, mainly using the theoretical framework of the bookMissionary discourses of difference. Negotiating Otherness in the British Empire, 1840–1900by Esme Cleall (2012).

Mapping the distribution of invasive tree species using deep one-class classification in the tropical montane landscape of Kenya

Some invasive tree species threaten biodiversity and cause irreversible damage to global ecosystems. The key to controlling and monitoring the propagation of invasive tree species is to detect their occurrence as early as possible. In this regard, one-class classification (OCC) shows potential in forest areas with abundant species richness since it only requires a few positive samples of the invasive tree species to be mapped, instead of all the species. However, the classical OCC method in remote sensing is heavily dependent on manually designed features, which have a limited ability in areas with complex species distributions. Deep learning based tree species classification methods mostly focus on multi-class classification, and there have been few studies of the deep OCC of tree species. In this paper, a deep positive and unlabeled learning based OCC framework—ITreeDet—is proposed for identifying the invasive tree species of Eucalyptus spp. (eucalyptus) and Acacia mearnsii (black wattle) in the Taita Hills of southern Kenya. In the ITreeDet framework, an absNegative risk estimator is designed to train a robust deep OCC model by fully using the massive unlabeled data. Compared with the state-of-the-art OCC methods, ITreeDet represents a great improvement in detection accuracy, and the F1-score was 0.86 and 0.70 for eucalyptus and black wattle, respectively. The study area covers 100 km2 of the Taita Hills, where, according to our findings, the total area of eucalyptus and black wattle is 1.61 km2 and 3.24 km2, respectively, which represent 6.78% and 13.65% of the area covered by trees and forest. In addition, both invasive tree species are located in the higher elevations, and the extensive spread of black wattle around the study area confirms its invasive tendency. The maps generated by the use of the proposed algorithm will help local government to develop management strategies for these two invasive species.

Death in the paddy field: Carcass decomposition and associated arthropods in subunits of a rice field landscape

Although rice production landscapes are often the scene of homicides, vertebrate decomposition and associated arthropods have never been described from rice paddies. Tropical rice landscapes are typically composed of irrigated/non-irrigated rice fields, fallow land (i.e., uncultivated fields), and low earthen levees (bunds) used as access pathways. The specific microclimatic and environmental conditions associated with each subunit of rice field landscapes are likely to impact carcass decomposition as well as the arthropod species associated with carrion. Here, we tested the hypothesis that the combined effects of constraints on arthropod colonization and survival, scarcity of necromass, limited habitat architecture, and recurrent disturbance limit the ability of carrion-related arthropods to colonize corpses and large carcasses in tropical rice-fields. Our results from monitoring pig carcasses in Philippine rice fields indicated that vertebrate decomposition in irrigated fields was slower and incomplete when compared to non-irrigated fields and bunds. Carcasses were colonized by a small complex of carrion-related arthropods that differed in composition and relative species abundance between dry bunds and relatively humid rice paddies. Fire ants (Solenopsis germinata) were observed frequently on carcasses exposed on bunds, rarely in non-irrigated fields, and almost never in irrigated fields. The presence of fire ants was associated with reduced blow fly (Chrysomya megacephala) abundance. Taken together, this indicates that the arthropod fauna associated with carcasses in tropical rice fields is relatively simple in contrast to the generally high arthropod diversity reported for other ecosystems at tropical latitudes. The limited richness of the community also means that an understanding of the development of one abundant calliphorid blow fly, C. megacephala, may be sufficient to investigate deaths and homicides under conditions similar to the ones described in this study.

Blended Finance: Konsep & Penerapan di Indonesia

This study aims to find out what and how Blended Finance is and specifically and to provide new insights and practical examples of Blended Finance in Indonesia. This research is qualitative research with a library study approach and interviews with practices in the field of Blended Finance. This research reveals a new definition of Blended Blended Finance as one of the systems that can answer the need for funds to make the SDGs a success by using the 4P funds, namely public, private, philanthropy and people. Blended Finance in Practice in Indonesia, among others, SDG Indonesia One, Tri Hita Karana Roadmap Blended Finance, The Sustainability Project Bond from the Tropical Landscape Finance Facility (TLFF), and the Marine and Fisheries Funding Institution (IPKP). The challenges in implementing Blended Finance in Indonesia are building a general knowledge base, lack of coordination or the emergence of ego institutions and the absence of appropriate projects or programs that are ready for financing. The existence of personnel or institutions as a tailoring project is the key to the success of blended finance.

Reduced litterfall and decomposition alters nutrient cycling following conversion of tropical natural forests to rubber plantations

Natural tropical landscapes have been continuously altered by land use change and other climate factors. Forest management practices have transformed massive tropical forests into rubber plantations throughout mainland Southeast Asia and Southwest China. However, the effect of the forest-to-plantation conversion on ecosystem functions associated with plant litter is limited. Here, we compare litterfall production, decomposition, nutrient return and nutrient use efficiency between a tropical natural forest (TNF) and a monoculture rubber plantation (MRP) in Xishuangbanna (China) over three years. Annual mean litterfall production was significantly higher in TNF (10.92 Mg ha−1 yr−1) than in MRP (5.23 Mg ha−1 yr−1). Production of leaf litter was positively correlated to that of total litterfall, suggesting that leaf litter could be reliably estimated from total litterfall. Temperature and solar radiation are dominant drivers of seasonal variation of litterfall production. The litterfall production was more sensitive to climate variables in MRP. The average stand litter and the decomposition quotient were 1.8 and 1.2 times greater in TNF than in MRP, respectively. The total nutrient return to the forest floor was 2.1 times higher in TNF (5.66 Mg ha−1 yr−1) than in MRP (2.76 Mg ha−1 yr−1); the return of each mineral element was significantly lower in MRP relative to TNF. The nutrient return preferentially occurred during the cold and dry seasons, which was consistent with the trend of litterfall. Relatively high N, P, Ca, and Mg use efficiencies were observed in MRP in line with their deficiency in the present tropical soils, indicating that rubber trees likely possess an efficient nutrient uptake mechanism to facilitate their adaption to oligotrophic habitats. Our results suggest that the large scale transformation of tropical forests to rubber plantations could alter the biogeochemical cycles related to litterfall, and thus possibly affect the resilience of ecosystems to climate variation. An increasing organic matter input in rubber monoculture may favor the sustainable development of rubber cultivation.

Dai in the “Land of Tropical Miasma”: Encounters of Early Chinese Anthropology in Yunnan

In early- to mid-twentieth century China, the tropical landscapes and indigenous peoples of southern Yunnan entered public consciousness in two different modes of representation: as a desolate and unfamiliar frontier fraught with the peril of diseases and in desperate need of environmental and social engineering; or, as a haven of fertile land with an ideal of harmonious society. In the process of making new senses of this tropical border region, anthropology played a major role as Chinese anthropologists working in this newly institutionalized discipline turned the Dai, traditionally regarded by Han people as a marginal group living within a dangerous land of zhangqi (tropical miasma), into an ethnographic subject. From Ling Chunsheng’s vision of environmental modification and medical advancement as a twofold project to engineer a new landscape and a new people, to Tian Rukang’s cultural critique that imagined the way of life of Dai people as an antidote for modernity, this article examines early Chinese anthropological discourses on the Dai people and their lived environment. I investigate how technological and epistemological changes fundamentally reshaped the meaning of tropical landscapes in China, a multi-ethnic country of a vast and diverse territory struggling to rejuvenate within a new global order, and I ponder the symbolic and material consequences of this recent history.

Portraits-in-Place from the Sotavento: A Photo-Dialogue between Abraham Bosque and J.A. Strub

Resulting from a series of conversations between its co-contributors, this photo-dialogue considers themes of nature-culture entanglements through the photographic work of Abraham Bosque, a documentary filmmaker and photojournalist who has lived in the Sotavento region of Mexico since 2017. Bosque’s work deals with the challenges implicit in portraying a tropical landscape whose vitality is the impetus for its extractivistic plunder. Through their conversations, Strub and Bosque consider eleven portraits-in-place that highlight, explore, and challenge ways of thinking about the relationships between humankind and nature, parochiality and globalization, tradition and modernity, beauty and violence, and the documentarian and their subject, all considered within the context of the Sotavento’s storied tropicality.

Tropical Topographies: Mapping the Malarial in The Calcutta Chromosome

This paper reads colonial archives of malaria in conjunction with Amitav Ghosh’s futuristic medical thriller The Calcutta Chromosome (1995) and contends that the novel, loosely based on Sir Roland Ross, ruptures narratives of colonial expertise. The colonial expertise on malaria is embodied by Ross, an officer in the Indian Medical Service; this is in contrast with the model of expertise proposed by the novel. While Ross’s expertise is predicated on the domination of nature and controlling diseased tropical landscapes, the novel resists imperial strategies of mapping and disease control. This paper argues that The Calcutta Chromosome presents an alternative attempt to map the malarial, rewriting history by displacing actors such as Ross and instead placing two colonial subjects, Murugan and Mangala, at the centre of new mapping practices. The novel further questions the notion of ‘colonial improvement’ which malaria facilitated in imperial regimes. Deviating from the colonial history of improving the native body and landscape as a cure for malaria, the novel foregrounds subjugated subjects working at the peripheries of laboratories and scientific practices and thus subverts the notion of the ‘improved subject’ by proposing the idea of the mutational, transformational ‘Calcutta chromosome.’

Impact of land-use changes on ant communities and the retention of ecosystem services in Rashad District, Southern Kordofan, Sudan

The ecological consequences of biodiversity loss are usually the reduction of ecosystem functions. These responses, however, differ depending on the type of land-use change and the ecological setting. We investigated the impact of land-use type and ecosystem functions on the ant assemblage of Rashad District, Sudan. We analysed the effects of three different land uses (soy monoculture, pasture and organic production of vegetables) on the ant community by assessing ant composition in 176 different locations. The collection sites were conventional soy monoculture, pastures, organic agriculture, and native vegetation such as Campo, Kubos, and forests. We recorded 264 ant species on the soil surface of the Rashad District, where 342 to 354 species were thought to exist. Pastures and organic agriculture areas have 61% and 56% of the native myrmecofauna, respectively, while conventional soy monoculture areas are home to only 17% of native ant species. Forest areas present a unique community, and soy monoculture areas have the strongest pattern of biotic homogenisation. We also detected that rare species (of low frequency) were the chief promoters of richness in the Rashad District, and the most threatened with local extinction, due to their low density and low occurrence in agrosystems. Overall, we found that agricultural expansion reduces ant diversity, particularly in soybean crops, and can affect ecosystem functions. To mitigate the reduction in the ant assemblage, we recommend the conservation of multiple natural habitats. Significance: Agricultural land conversion and climate change play a major role in shaping tropical landscapes, but the direct and indirect links to biodiversity and species community composition remain poorly understood. Ant richness is correlated with biomass, demonstrating that the effects on ecosystem function are dependent on the particularities of each assessed function (such as resource type), the types of land uses, and the abundance of ants in the region. Land-use effects on ant diversity were strongly scale dependent. The highest ant diversity occurred in soy monoculture areas.