Ecological Questions Research Articles

30 years of terrestrial insect richness patterns across elevation: What have we learned? A global meta-analysis.

Understanding elevation variation in biodiversity is a classic question in ecology and has implications for understanding climate change impacts on mountain ecosystems. While insects are the largest group of animals, the global trend in insect species richness with elevation is unknown. To date, single studies and taxa-specific syntheses have provided no single picture, finding variable patterns of insect richness with elevation. A global synthesis across systems would provide a better understanding of how insect species richness changes with elevation and the possible environmental correlates of those patterns. We used published studies of terrestrial insect elevation gradients from 1990 to 2020 to ask: How do insect species richness change with elevation, and which environmental variables best explain this relationship statistically? With 1486 sites spanning 151 species richness-elevation gradients from 80 studies from four diverse insect taxonomic groups and five biomes, we found that overall proportional richness reached a low-elevation plateau and then decreased. We also show that mean annual temperature and seasonality best explain this trend. We suggest best practices and areas of interest for the future of insect richness-elevation studies, including underrepresented groups, geographic areas, and more standardized methods.

Plant traits and seasonality shape coexistence and niche segregation patterns among spider species.

Understanding the mechanisms that enable species coexistence is a central question in ecology, as it helps to comprehend species diversity. One of the most common stabilizing mechanisms of coexistence is niche segregation, which can prevent the competitive exclusion of the fittest competitor. Niche segregation can manifest itself at various temporal and spatial scales, allowing provide essential insights into understanding the stabilizing mechanisms facilitating the coexistence of species. We assessed coexistence patterns among flower-dwelling spiders in two ways, in the first set of analyses, we investigated the factors influencing the quantity of spider individuals and species. The second approach we investigate the spatio-temporal segregation between species, effectively examining the coexistence patterns. We observed that the presence of inflorescences per plant, the number of flowers per inflorescence, and the presence of EFNs play a significant role in increasing spider abundance and richness. We find only a marginal seasonal effect, suggesting that spiders have constant access to resources throughout the year. Our niche overlap analysis demonstrated synchrony in the spatial occupation of niches by different spider species. The coexistence patterns appeared to be unaffected by the number of inflorescences. The greater number of inflorescences will enable a greater availability of niches, and consequently more abundance and richness of species of spiders the plant can sustain. Our results suggest that, to mitigate the adverse consequences of competitive interactions, spiders tend to adopt spatial partitioning as a strategy to facilitate the coexistence of spiders living in reproductive structures on plants in the Brazilian savanna.

BEpipeR: a user-friendly, flexible, and scalable data synthesis pipeline for the Biodiversity Exploratories and other research consortia

Abstract Background Large research consortia can generate tremendous amounts of biological information, including high-resolution soil, vegetation, and climate data. While this knowledge stock holds invaluable potential for answering evolutionary and ecological questions, making these data exploitable for modelling remains a daunting task due to the many processing steps required for synthesis. This might result in many researchers to fall back to a handful of ready-to-use data sets, potentially at the expense of statistical power and scientific rigour. In a push for a more stringent approach, we introduce BEpipeR, an R pipeline that allows for the streamlined synthesis of plot-based Biodiversity Exploratories data. Methods BEpipeR was designed with flexibility and ease of use in mind. For instance, users simply choose between aggregating forest or grassland data, or a combination thereof, effectively allowing them to process any experimental plot data of this research consortium. Additionally, instead of coding, they parse most processing information in a user-friendly way through parameter sheets. Processing includes, among others, the creation of a spatially explicit plot-ID template, data wrangling, quality control, plot-wise aggregations, the calculation of derived metrics, data joining to a large composite data set, and metadata compilation. Results With BEpipeR, we provide a feature-rich pipeline that allows users to process Biodiversity Exploratories data in a flexible and reproducible way. This pipeline might serve as a starting point for aggregating the numerous data sets of this and potentially similar research consortia. In this way, it might be a primer for the construction of consortia-wide composite data sets that take full advantage of the consortia’s rich information stocks, ultimately boosting the visibility and participation of individual research projects. Conclusions The BEpipeR pipeline permits the user-friendly processing and plot-wise aggregation of Biodiversity Exploratories data. With modifications, this framework may be easily adopted by other research consortia.

Low‐cost animal tracking using Bluetooth low energy beacons on a crowd‐sourced network

Abstract Animal tracking has opened the door to address many fundamental questions in ecology and conservation. Whilst historically animals have been tracked as a means to understand their large‐scale movements, such as migration, there is now a greater focus on using tracking to study movements over smaller scales, individual variation in movement or how movements shape social network structure. With this shift in focus also comes different tracking needs, including the need to track larger numbers of individuals. Tracking studies all face some technological limitations. For example, GPS and other active tracking solutions can collect fine‐scale movement data, but have a high cost per tag, limiting the number of individuals that can be followed. They also have high low‐energy costs of data acquisition and download, limiting time periods over which data can be collected. Low‐energy passive (e.g. PIT) or active (e.g. reverse GPS) tags can overcome these limitations, but instead require animals to remain within a bounded study area or to come into close proximity to detectors. Here we describe one solution that can overcome many current limitations by employing the massive global network of personal mobile phones as gateways for tracking animals using Bluetooth low‐energy (BLE) beacons. In areas with medium to high density of people, these simple‐to‐make beacons can provide regular updates of position over long time periods (battery life 1–3 years). We describe how to use off‐the‐shelf components to produce BLE beacons that weigh c. 5–6 g and cost <$7USD. Using field‐testing, we then show that beacons are capable of producing high‐frequency tracking data that can be used to build home ranges or to detect spatiotemporal co‐occurrences among individuals. BLE beacons are a low cost, low‐energy solution for studying organisms (e.g. birds, mammals and reptiles) living and moving in urban landscapes. Their low weight and small size makes them particularly well‐suited for tracking smaller species. When combined with fixed gateways, their use can also be extended to non‐urban habitats. Their high accessibility is likely to make them an attractive solution for many research projects.

Driving factors of phytoplankton Reynolds functional groups (RFGs) in a subtropical reservoir (São Paulo, Brazil)

Subtropical reservoirs are susceptible to the eutrophication process, largely due to inappropriate land use and occupation in the watersheds, resulting in changes in the composition of the phytoplankton community, according to the sensitivity and environmental tolerances of the different species. Application of the Reynolds functional groups (RFGs) method to the multispecies phytoplankton community is a valuable approach that can be used to answer ecological questions at different spatial and temporal scales. The Itupararanga reservoir, in the upper Sorocaba River basin (São Paulo state, Brazil), is used to supply drinking water to approximately one million people, as well as for agricultural and recreational purposes. This study examines the relationships between environmental variables and the composition of the phytoplankton community, identifying the main functional groups (RFGs) along a spatial gradient in the reservoir (from upstream to downstream), during one year. Five samplings were performed at seven points in the reservoir, in the rainy and dry seasons (from 2016 to 2017). The effects of spatial heterogeneity influenced the formation of different biomass gradients for each functional group. The most abundant RFGs were Sn (warm mixed environments), H1 (eutrophic, both stratified and shallow lakes with low nitrogen content), and Lo (deep and shallow, oligotrophic to eutrophic, medium to large lakes), which corresponded to the spatial heterogeneity of the reservoir. The variables with the greatest influence on the phytoplankton composition in the reservoir were total nitrogen, nitrite, and the N/P ratio, with phosphorus as the limiting nutrient. The presence of Cyanobacteria (codons Sn and H1) was driven by the stability of the water column, due to the long residence time of the water in the reservoir. This research demonstrated the effectiveness of using RFGs as environmental descriptors, providing an essential tool in aquatic ecology studies.

The Impact of Winter Cover Crops on Soil Nematode Communities and Food Web Stability in Corn and Soybean Cultivation.

There is increasing adoption of winter cover crops (WCCs) in corn and soybean production in Canada, primarily to reduce erosion and increase soil organic matter content. WCCs have the potential to influence nematode communities by increasing free-living nematodes and decreasing plant-parasitic nematodes or vice versa. However, the mechanism by which WCCs change nematode community assemblages still remains a key question in soil food web ecology. We tested the hypothesis that the long-term use of rye (Secale cereale), barley (Hordeum vulgare) and oat (Avena sativa) as monocultures or mixtures promotes nematode communities and improves overall soil health conditions compared to winter fallow. The results from this study revealed that the use of WCCs generally promoted a higher abundance and diversity of nematode communities, whereas plant parasitic nematodes were the most abundant in winter fallow. Moreover, the mixtures of WCCs had more similar nematode communities compared to rye alone and winter fallow. The structure and enrichment indices were higher with WCCs, indicating higher nutrient cycling and soil suppressiveness, which are signs of healthy soil conditions. Furthermore, WCCs significantly reduced the populations of root lesion nematode Pratylenchus, although their numbers recovered and increased during the main crop stages. Additionally, mixtures of WCCs promoted the highest abundance of the stunt nematode Tylenchorhynchus, whereas winter fallow had a higher abundance of the spiral nematode Helicotylenchus during the fallow period and the main crop stages. The results show that the long-term use of cover crops can have a positive impact on nematode communities and the soil food web, but these changes depend on the type of WCCs and how they are used.

Mathematical lipid correction of δ13C and effect of lipid extraction on δ15N of European eel (Anguilla anguilla) muscle: Lipid correction of δ13C in European eels.

Carbon (δ13C) and nitrogen (δ15N) stable isotope analysis is a powerful tool to investigate diverse questions in fish ecology, such as their trophic position or migration strategies. These questions appear particularly important to protect endangered European eel. However, elevated lipid content in eel muscle can bias δ13C values, as lipids are 13C-depleted compared to proteins and carbohydrates. We measured δ13C and δ15N values of bulk and lipid-free samples of eel muscle. Lipid-free samples were obtained after the extraction of lipids with cyclohexane. Lipid-corrected δ13C values, using five different mathematical equations based on bulk δ13C values, were compared to lipid-free δ13C values. We also evaluated the effect of lipid extraction on δ15N values. The analyses were based on linear regression performed on 333 individuals captured in nine lagoons and four rivers. Independently to the capture site or habitat (river or lagoon), the predicted lipid-corrected δ13C values were highly consistent with the measured lipid-free δ13C values (R2 > 0.90). The application of specific equations for each habitat or capture site only slightly increases these R2 (1.5% or less). The lipid extraction treatment significantly decreased by 0.2‰ the δ15N values compared to bulk samples. Given the excellent prediction of mathematical equations and the small decrease of δ15N values after lipids extraction, we propose to use mathematical correction to estimate δ13C values of eel muscle. As the habitats or sites did not strongly influence the results, the coefficients from our study can be applied to other studies on European eel.

Impacts of counting protocols for light microscopy on estimates of biodiversity and algal density of phytoplankton

AbstractKnowledge on the biodiversity and abundance of phytoplankton is key for many ecological and societal (e.g., blue growth) questions. Gathering temporal variation and spatial patterns on key indicators requires reliable and standardized protocols on sampling, species identification and counting. Numerous methods are used but consequences for comparing the biodiversity and abundance of phytoplankton of these different techniques are not well known. We evaluated the consequences of different counting protocols using light microscopy (i.e., subsampling transects or wedges within counting chambers) for these indices using samples collected weekly to bi‐weekly (n = 398, 2009–2018) from the Wadden Sea (southern North Sea). Phytoplankton cells were counted (by one person under similar conditions) in a fixed number of viewing fields (58, 70, and 29) at three respective magnifications (10 × 100, 10 × 40, and 10 × 10). Patterns in the spatial distribution of phytoplankton cells varied among species and clustering of cells occurred in more than one‐fifth of the samples. This will induce error in the conversion from counts (per viewing field) to abundance (cells mL−1). Our present effort resulted in a high accuracy (95%) in overall cell abundances. This was not the case for species richness, for example, capturing 90% of all species present in the sample would require an almost threefold increase in effort for the 10 × 40 and 10 × 10 magnifications. We recommend that counting methods be tailored to the main research objectives and that counting protocols should quantify uncertainty as well as potential bias to provide an estimation of the error in phytoplankton abundance and species composition.

Profiling of charge characteristics and effect of pH on charge dynamics in cyprinid milt

Electrostatic properties of milt have a huge bearing on the reproductive success of externally fertilizing freshwater fish species. Considering the global significance of carp in aquaculture, we explored the charge profile of milt of ten commercially important carp species for the first time. Mean zeta potential of milt ranged from (−) 33.86 mV in Cirrhinus mrigala to (−) 56.34 mV in Systomus sarana at pH 7.0. The effect of pH on milt characteristics was studied with Labeo rohita as the model species. Zeta potential reduced significantly upon exposure to low pH (4.0) and increased at alkaline pH (10.0). Fertilization rate was significantly reduced at acidic pH. Our results indicate that changes in milt zeta potential due to acidic pH is a significant factor in reduced reproductive success of externally fertilizing freshwater fish. While low concentration of proteases were detected in milt, it remained in a stable colloidal form even after incubation for 18 h at room temperature with no significant difference in the mean zeta potential at the end of incubation. This seminal work on milt zeta potential of carp will open several avenues in aquaculture and fisheries for productivity enhancement and conservation. Study of the electrostatic properties of milt can also help explain puzzling questions of ecology, such as migratory behavior.

Viromes vs. mixed community metagenomes: choice of method dictates interpretation of viral community ecology

BackgroundViruses, the majority of which are uncultivated, are among the most abundant biological entities on Earth. From altering microbial physiology to driving community dynamics, viruses are fundamental members of microbiomes. While the number of studies leveraging viral metagenomics (viromics) for studying uncultivated viruses is growing, standards for viromics research are lacking. Viromics can utilize computational discovery of viruses from total metagenomes of all community members (hereafter metagenomes) or use physical separation of virus-specific fractions (hereafter viromes). However, differences in the recovery and interpretation of viruses from metagenomes and viromes obtained from the same samples remain understudied.ResultsHere, we compare viral communities from paired viromes and metagenomes obtained from 60 diverse samples across human gut, soil, freshwater, and marine ecosystems. Overall, viral communities obtained from viromes had greater species richness and total viral genome abundances than those obtained from metagenomes, although there were some exceptions. Despite this, metagenomes still contained many viral genomes not detected in viromes. We also found notable differences in the predicted lytic state of viruses detected in viromes vs metagenomes at the time of sequencing. Other forms of variation observed include genome presence/absence, genome quality, and encoded protein content between viromes and metagenomes, but the magnitude of these differences varied by environment.ConclusionsOverall, our results show that the choice of method can lead to differing interpretations of viral community ecology. We suggest that the choice of whether to target a metagenome or virome to study viral communities should be dependent on the environmental context and ecological questions being asked. However, our overall recommendation to researchers investigating viral ecology and evolution is to pair both approaches to maximize their respective benefits.ADm-mTTAXM3aVZwCyoroCBVideo

Distribution and habitat use by the Audouin's Gull (Ichthyaetus audouinii) in anthropized environments

Human activities provide wildlife with highly abundant and predictable food subsidies, which can affect population dynamics and have wide-ranging ecological impacts. A key ecological question is how species adapt their foraging behaviour to capitalize on these new feeding opportunities. We investigate habitat use by Audouin's Gulls (Ichthyaetus audouinii) off the Western Mediterranean Sea, an opportunistic seabird that has recently expanded to diverse breeding colonies subjected to varying degrees of human influence. By combining GPS tracking, remote sensing, and GIS, we assessed the resource selection and habitat preferences of gulls from five colonies across their breeding latitudinal range, including interactions with industrial fisheries. Overall, the use of terrestrial habitats was slightly higher (57 % of total positions) compared to the marine environment (42 %), with individuals preferentially feeding on urban and related areas or fishing ports. However, habitat utilization varied among studied colonies, likely in response to contrasting food availability and accessibility of human related food resources on land (e.g., agriculture and livestock areas, landfills or rice fields). At sea, individuals largely distributed over highly productive and persistent marine areas with intense fishing pressure. Individuals also adapted their daily activity patterns to match food availability: gulls preferentially feed on the marine environment during the night, while the use of terrestrial habitats increases during daylight hours. Individuals' daily activity patterns also matched that for the two main fishing gears operating in the area: diurnal trawlers and nocturnal purse-seiners. Our findings offer perspectives on the reliance of opportunistic seabird species on anthropogenic food subsidies and inform on potential implications for the conservation and management of these under changes in fishing policies (EU discard ban). Broadly, we provide further insights on how this species can adapt to changing environments.

Keystone species in an urban environment: Do raptors control the Mexican gray squirrel in Mexico City?

Urbanization has forced animals to respond to novel environments. One of the basic questions in urban ecology is if ecological processes that occur in natural conditions also occur in urban environments. In natural ecosystems, key predators can limit prey abundance and have a widespread effect on trophic levels. Here, we examine a predator-prey interaction in Mexico City, an urban ecosystem where prey can be evaluated in the presence or absence of apex predators. Nearly all original ecosystems in Mexico City have been transformed for human purposes. Many of the green spaces in the city contain populations of the Mexican gray squirrel, a species native to this area. These green spaces are also inhabited by different species of raptors, the most frequent being Harris's hawk, Cooper's hawk, and sharp-shinned hawk. Little is known about the interactions between raptors and squirrels, particularly how different environmental factors influence this ecological relationship. We do know, however, that raptors prey on squirrels. We predicted that in parks where raptors were present, there would be fewer squirrels than in parks where there were no raptors. We studied the relationship between raptors and squirrels using occupancy models, which also allowed us to evaluate environmental factors that affect the presence of both squirrels and raptors. We also tested if the presence of raptors influenced the occupancy probability of squirrels, and vice versa. Lastly, we estimated the abundance of squirrels in parks, both where raptors were present and where they were absent. Contrary to our predictions, in our first two sampling periods we found a positive relationship between the presence of raptors and squirrel abundance, but this relationship was absent during our second two survey periods, which was due to a decline in squirrel abundance in parks where raptors were present. These results suggest that predator-prey interactions occur in urban settings much as they do under natural conditions, but that other factors unique to urbanization can also impact the abundance of raptors and squirrels. Our findings also suggest that raptors might be an effective means of controlling squirrel populations under some conditions.

Characterizing a stable five-species microbial community for use in experimental evolution and ecology.

Model microbial communities are regularly used to test ecological and evolutionary theory as they are easy to manipulate and have fast generation times, allowing for large-scale, high-throughput experiments. A key assumption for most model microbial communities is that they stably coexist, but this is rarely tested experimentally. Here we report the (dis)assembly of a five-species microbial community from a metacommunity of soil microbes that can be used for future experiments. Using reciprocal invasion-from-rare experiments we show that all species can coexist and we demonstrate that the community is stable for a long time (~600 generations). Crucially for future work, we show that each species can be identified by their plate morphologies, even after >1 year in co-culture. We characterise pairwise species interactions and produce high-quality reference genomes for each species. This stable five-species community can be used to test key questions in microbial ecology and evolution.

What Is Animal Prehistory?

This paper engages animal archaeologies with key debates in animal history. Animal archaeology is currently and primarily framed as a multi-species venture, and a brief review of its disciplinary genealogies illustrates dominant foci on questions of ecology and (posthuman) ontology. I argue that this situation, paradoxically, has led archaeologists to largely neglect the challenges of the historical animal. To overcome this constriction, animal archaeology needs to conceive of itself also as a critical and conceptual project—coevally celebrating and problematizing the notion of “the animal.” Importantly, this project pivots to questions of historicity, with regard to both its animal subjects of study and animal scholarship itself. I position “animal prehistory” as a strategic lens to bring to the fore and interrogate these unattended animal specificities and articulate them with long-standing concerns in animal history. I suggest this can proffer a new, exciting field of inquiry and exchange for both historians and archaeologists.

The diversity of ants in moderately isolated islands of Japan: towards understanding of factors affecting their colonisation success

ABSTRACT How species diversity is determined is an old question in community ecology but is not yet well understood. Island biotas offer opportunities to address this issue. Here, the ant fauna was studied in five moderately isolated islands of Japan and compared with those in reference regions on the nearby main islands to assess whether ants’ ecological characteristics affect their island colonisation success. Species that were more abundant in the reference regions were more frequently found on the islands, suggesting that ant communities on these islands are likely to have a nested subset structure. Species inhabiting both forests and open lands tended to occur more frequently in the study islands at least than those exclusively inhabiting forests, but this difference was not significant. In addition, nest sites and worker body size did not have significant effects on their occurrence in these islands. These results seem to suggest that the study islands as a whole offer various environments that support a variety of ant species with different ecological characteristics. It is suggested in this study that island size affects the species richness, as has often been reported.

Anthropogenic disturbance and competitive avoidance shape the coexistence pattern of macaque species in tropical forests

AbstractThe factors that enable the coexistence of closely related species remain a major question in ecology, particularly in human‐disturbed habitats. The effects of anthropogenic disturbance and interspecific competition can exacerbate the decline in populations of competing species. The adoption of different strategies in responding to anthropogenic disturbances and competitive avoidances may create opportunities for competing species to coexist. However, few studies have explored how disturbance and competition interact to shape species coexistence. In this study, we conducted long‐term and large‐scale camera trap surveys comprising 540 sampling sites from 2017 to 2021 at Xishuangbanna, southwestern China, and deployed a spatiotemporal analysis framework to determine the effect of anthropogenic disturbances and competitive avoidances on the coexistence of three sympatric macaque species: Assamese macaque (Macaca assamensis; MA), northern pig‐tailed macaque (M. leonina; ML), and rhesus macaque (M. mulatta; MM). Macaque species exhibited diverse responses to different types of anthropogenic disturbances. The occurrence probability of MM was positively associated with distance to road and relative abundance of human occurrence, and negatively associated with distance to cropland, which reduces the likelihood of sympatry between MM and the other two species due to their opposing responses to road, cropland, and human occurrence. Conversely, the similar responses to road and cropland increase the sympatry between MA and ML. Three macaque species did not avoid each other through shifting space use or their overall daily activity pattern. However, they delayed using the shared site after other species used it to avoid confrontation. We provide evidence that (1) the spatial co‐occurrence pattern of sympatric macaque species was determined by anthropogenic disturbances rather than by competitive spatial avoidance and (2) fine‐scale temporary avoidance is the strategy to alleviate their interspecific competition. These results enhance our understanding of the underlying mechanisms leading to species coexistence of nonhuman primates in human‐disturbed habitats.

Thinking and Unthinking the Present: Philosophy after Foucault

What might a contemporary philosophical practice after and following Foucault look like? After briefly analyzing Foucault’s rather ambiguous stance towards academic philosophy in his posthumously published Le discours philosophique, we argue for continuing his historico-philosophical practice of diagnosing the present. This means taking up his analytic heuristic (with its three dimensions of power, knowledge and subjectivity) rather than his more concrete diagnostic concepts and the specific historical results they yield. We argue that the common methodological operation on each of the three axis is to shift the perspective from the given legitimacies, norms, identities and selves to their historical, conflict-ridden emergence. Practicing philosophy in this way allows developing Foucauldian contributions in two contemporary philosophical debates: critical ontology and political epistemology. While ontology and epistemology might seem surprising fields to work in for philosophers inspired by and critically loyal to Foucault, we attempt to dispel these reservations and illustrate the stakes in both debates, pointing to the urgent issues of ecological questions and of the problematization of untruths in politics respectively.

Network theory and migration: Avoiding misapplications and misinterpretations

Network analysis is becoming a popular tool for the study of animal movement. Proliferation of software enables researchers to use network measures without reflecting on the underlying mathematics and biology. One common use characterizing movement networks, such as migration, with centrality measures. Predominantly developed to evaluate social systems, these measures now appear in applications across disciplines that vary greatly in system properties. Each network measure has a very specific mathematical definition, with implicit assumptions about system properties to which they are applied that often make them inappropriate for migration. We report mismatches between mathematical assumptions and applications of network measures to migration, primarily with bird examples. For example, of 11 trajectory-transmission network-flow processes observed in the real world, only two are applicable to bird migration, neither of which allows valid application of classical centrality measures. We also identify misinterpretations of network measures, such as nodes with the highest degree centrality as locations where individuals intermingle. Other misinterpretations include that a high betweenness score translates to a node that is frequently used or is an important site along a main migratory route. Finally, networks are used in different ways, ranging from descriptive visualization to quantitative prediction and we identify common cases, such as migratory connectivity, where this leads to miscommunication. Network-theoretic approaches to answer ecological research and conservation questions associated with migration are numerous, but new measures need to be developed for animal migration. We provide a guide for researchers of animal movement for measure selection, development, and documentation.

Reading the Agrarian, National, and Ecological Questions in Contemporary Kisan Politics in Pakistan

In the 2010s, the Pakistan Kissan Ittehad (PKI) emerged in Punjab as a militant movement that brought together different fractions of agrarian producers against the IMF-proposed removal of electricity subsidies for agricultural tube wells. The article draws on fieldwork with the PKI in 2018–2019 to understand its trajectories since its contestation of one aspect of the agenda of structural reform. I argue that the analytical framework of “agrarian populism,” which has recently come back into use to understand agrarian politics, poses limitations in differentiating agrarian movements from each other. By focusing on how the PKI navigates the intersection between the agrarian, national, and ecological questions, the article shows how the movement has approached agrarian market reform, ecological crisis, and national development. Through this discussion, it undertakes a critical assessment of the PKI and situates it with longer histories of class differentiation, agrarian change, and ecological transformation.

Using joint species distribution modelling to identify climatic and non‐climatic drivers of Afrotropical ungulate distributions

The relative importance of the different processes that determine the distribution of species and the assembly of communities is a key question in ecology. The distribution of any individual species is affected by a wide range of environmental variables as well as through interactions with other species; the resulting distributions determine the pool of species available to form local communities at fine spatial scales. A challenge in community ecology is that these interactions (e.g. competition, facilitation, etc.) often are not directly measurable. Here, we used hierarchical modelling of species communities (HMSC), a recently developed framework for joint species distribution modelling, to estimate the role of biotic effects alongside environmental factors using latent variables. We investigate the role of these factors determining species distributions in communities of Artiodactyla, Perissodactyla and Proboscidea in the Afrotropics, an area of peak species richness for hoofed mammals. We also calculate pairwise trait dissimilarity between these species, from a mixture of morphological and behavioural traits, and investigate the relationship between dissimilarity and estimated residual co‐occurrence in the model. We find that while ungulate distributions appear to be predominantly determined (~ 70%) by climatic variables, such as precipitation, a substantial proportion of the variance in ungulate species distributions (~ 30%) can also be attributed to modelled latent variables that likely represent a combination of dispersal barriers and biotic factors. Although we find only a weak relationship between residual co‐occurrence and trait dissimilarity, we suggest that our results may show evidence that biotic factors, likely influenced by historical barriers to species dispersal, are important in determining species communities over a continental area. The HMSC framework can be used to provide insight into factors affecting community assembly at broad scales, and to make more powerful predictions about future species distributions as we enter an era of increasing impacts from anthropogenic change.