Effects of extreme land fragmentation on wildlife and livestock population abundance and distribution

Introgression and disruption of migration routes have shaped the genetic integrity of wildebeest populations

The blue wildebeest (Connochaetes taurinus) is a keystone species in savanna ecosystems from southern to eastern Africa, and is well known for its spectacular migrations and locally extreme abundance. In contrast, the black wildebeest (C. gnou) is endemic to southern Africa, barely escaped extinction in the 1900s and is feared to be in danger of genetic swamping from the blue wildebeest. Despite the ecological importance of the wildebeest, there is a lack of understanding of how its unique migratory ecology has affected its gene flow, genetic structure and phylogeography. Here, we analyze whole genomes from 121 blue and 22 black wildebeest across the genus' range. We find discrete genetic structure consistent with the morphologically defined subspecies. Unexpectedly, our analyses reveal no signs of recent interspecific admixture, but rather a late Pleistocene introgression of black wildebeest into the southern blue wildebeest populations. Finally, we find that migratory blue wildebeest populations exhibit a combination of long-range panmixia, higher genetic diversity and lower inbreeding levels compared to neighboring populations whose migration has recently been disrupted. These findings provide crucial insights into the evolutionary history of the wildebeest, and tangible genetic evidence for the negative effects of anthropogenic activities on highly migratory ungulates.

Worse sleep and increased energy expenditure yet no movement changes in sub-urban wild boar experiencing an influx of human visitors (anthropulse) during the COVID-19 pandemic

Expansion of urban areas, landscape transformation and increasing human outdoor activities strongly affect wildlife behaviour. The outbreak of the COVID-19 pandemic in particular led to drastic changes in human behaviour, exposing wildlife around the world to either reduced or increased human presence, potentially altering animal behaviour. Here, we investigate behavioural responses of wild boar (Sus scrofa) to changing numbers of human visitors to a suburban forest near Prague, Czech Republic, during the first 2.5 years of the COVID-19 epidemic (April 2019-November 2021). We used bio-logging and movement data of 63 GPS-collared wild boar and human visitation data based on an automatic counter installed in the field. We hypothesised that higher levels of human leisure activity will have a disturbing effect on wild boar behaviour manifested in increased movements and ranging, energy spent, and disrupted sleep patterns. Interestingly, whilst the number of people visiting the forest varied by two orders of magnitude (from 36 to 3431 people weekly), even high levels of human presence (>2000 visitors per week) did not affect weekly distance travelled, home range size, and maximum displacement of wild boar. Instead, individuals spent 41 % more energy at high levels of human presence (>2000 visitors per week), with more erratic sleep patterns, characterised by shorter and more frequent sleeping bouts. Our results highlight multifaceted effects of increased human activities ('anthropulses'), such as those related to COVID-19 countermeasures, on animal behaviour. High human pressure may not affect animal movements or habitat use, especially in highly adaptable species such as wild boar, but may disrupt animal activity rhythms, with potentially detrimental fitness consequences. Such subtle behavioural responses can be overlooked if using only standard tracking technology.

New land tenure fences are still cropping up in the Greater Mara

Expanding and intensifying anthropogenic land use is one of the greatest drivers of changes of biodiversity loss and political inequality worldwide. In the Greater Mara, Kenya, a trend of private land enclosure is currently happening, led by smallholders wishing to protect and uphold their land titles. Here we expand on previous work by Løvschal et al. quantifying the rapid, large-scale development of fencing infrastructure that began in 1985 but has increased by 170% from 2010 onwards. We provide fine-scale analysis of the spatial and temporal trends in fencing using high-resolution Sentinel-2 imagery. The formally unprotected regions have distinctly more fences than the rest of the Mara, one experiencing a 740% increase in fenced land in four years. Conservancies have an effect in stemming fencing but fences crop up within and along conservancy boundaries. We estimate the actual geographical coverage of the fences in the Mara to be 130,277 ha (19% of the total region) using an error margin of 8%, derived by calibrating our satellite mapping with ground-truth data. The study suggests the need for revising community-based eco-conservation efforts and pursuing a richer understanding of the socio-political and historical dynamics underlying this phenomenon.

Crop damage by vertebrates in Latin America: current knowledge and potential future management directions

Background

Crop farming contributes to one of the most extensive land use activities in the world, and cropland areas continue to rise. Many vertebrate species feed on crops, which has caused an increase in human-wildlife conflicts in croplands. Crop-feeding damages the economy of local communities and causes retaliation against the responsible vertebrates in several forms, including lethal practices such as hunting and poisoning. Lethal control may cause the local extirpation of some species, affecting ecological processes and patterns. Therefore, it is necessary to find non-lethal alternatives that can protect both local economies and wildlife. Research has been conducted in Africa and Asia, focusing on elephants and primates, and the effectiveness of some non-lethal alternatives, such as chili-based repellents and beehives, is being investigated. However, there has been very little research on this topic in Central and South America. The goal of this review is to assess the current knowledge on crop damage by vertebrates in Central and South America and indicate future research directions.

Survey methodology

We reviewed the available scientific literature reporting crop damage by vertebrates in Central and South America, and the Caribbean, published between 1980 and 2020, through systematic searches on Web of Science, Scopus, and Google Scholar. We analyzed the temporal and geographical distributions of the studies, the crops and vertebrate species these studies considered, the crop protection techniques used, and their effectiveness.

Results

We retrieved only 113 studies on crop damage by vertebrates in Latin America, but there was an increasing trend in the number of studies published over time. Most of the studies were conducted in Brazil, Argentina, Mexico, and Costa Rica. Four orders of mammals (Rodentia, Carnivora, Artiodactyla, and Primates) and four orders of birds (Passeriformes, Columbiformes, Psittaciformes, and Anseriformes) were the most common groups of crop-feeding vertebrates. The most prominent crop was corn, which was featured in 49% of the studies. Other notable crops include rice, sorghum, and sugarcane. The most reported method for protecting crops was lethal control through hunting or poisoning. Non-lethal techniques were found to be less prevalent. Less than half of the studies that mentioned the use of protection techniques indicated their effectiveness, and only 10 studies evaluated it by performing scientific experiments and reporting their results.

Conclusions

Central and South America is still underrepresented in research on vertebrate crop-feeding. There is a need for experimentation-based robust research to find crop protection techniques that minimize harm to vertebrates while effectively reducing damage to crops. While this is being studied, habitat loss and fragmentation need to be halted to prevent the native vertebrates from turning to crops for food.

Increasing Anthropogenic Disturbance Restricts Wildebeest Movement Across East African Grazing Systems

The ability to move is essential for animals to find mates, escape predation, and meet energy and water demands. This is especially important across grazing systems where vegetation productivity can vary drastically between seasons or years. With grasslands undergoing significant changes due to climate change and anthropogenic development, there is an urgent need to determine the relative impacts of these pressures on the movement capacity of native herbivores. To measure these impacts, we fitted 36 white-bearded wildebeest (Connochaetes taurinus) with GPS collars across three study areas in southern Kenya (Amboseli Basin, Athi-Kaputiei Plains, and Mara) to test the relationship between movement (e.g., directional persistence, speed, home range crossing time) and gradients of vegetation productivity (i.e., NDVI) and anthropogenic disturbance. As expected, wildebeest moved the most (21.0 km day–1; CI: 18.7–23.3) across areas where movement was facilitated by low human footprint and necessitated by low vegetation productivity (Amboseli Basin). However, in areas with moderate vegetation productivity (Athi-Kaputiei Plains), wildebeest moved the least (13.3 km day–1; CI: 11.0–15.5). This deviation from expectations was largely explained by impediments to movement associated with a large human footprint. Notably, the movements of wildebeest in this area were also less directed than the other study populations, suggesting that anthropogenic disturbance (i.e., roads, fences, and the expansion of settlements) impacts the ability of wildebeest to move and access available resources. In areas with high vegetation productivity and moderate human footprint (Mara), we observed intermediate levels of daily movement (14.2 km day–1; CI: 12.3–16.1). Wildebeest across each of the study systems used grassland habitats outside of protected areas extensively, highlighting the importance of unprotected landscapes for conserving mobile species. These results provide unique insights into the interactive effects of climate and anthropogenic development on the movements of a dominant herbivore in East Africa and present a cautionary tale for the development of grazing ecosystems elsewhere.

Landscape Dynamics (landDX) an open-access spatial-temporal database for the Kenya-Tanzania borderlands

The savannas of the Kenya-Tanzania borderland cover >100,000 km² and is one of the most important regions globally for biodiversity conservation, particularly large mammals. The region also supports >1 million pastoralists and their livestock. In these systems, resources for both large mammals and pastoralists are highly variable in space and time and thus require connected landscapes. However, ongoing fragmentation of (semi-)natural vegetation by smallholder fencing and expansion of agriculture threatens this social-ecological system. Spatial data on fences and agricultural expansion are localized and dispersed among data owners and databases. Here, we synthesized data from several research groups and conservation NGOs and present the first release of the Landscape Dynamics (landDX) spatial-temporal database, covering ~30,000 km² of southern Kenya. The data includes 31,000 livestock enclosures, nearly 40,000 kilometres of fencing, and 1,500 km² of agricultural land. We provide caveats and interpretation of the different methodologies used. These data are useful to answer fundamental ecological questions, to quantify the rate of change of ecosystem function and wildlife populations, for conservation and livestock management, and for local and governmental spatial planning.

Measurement(s)	livestock enclosures • agriculture • fence
Technology Type(s)	digital curation
Sample Characteristic - Environment	savanna
Sample Characteristic - Location	East Africa

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.16828204

Examining Drivers of Divergence in Recorded and Perceived Human-Carnivore Conflict Hotspots by Integrating Participatory and Ecological Data

Human-carnivore conflict is a global challenge with complex and context-specific causes and consequences. While spatial analyses can use ecological principles to predict patterns of conflict, solutions to mitigate conflict must also be locally adaptable, sustainable, and culturally-sensitive. In Nakuru County, Kenya, rapid development and land subdivision have exacerbated conflict by isolating wildlife in protected areas that are increasingly adjacent to human settlements. In an effort to understand local perspectives on carnivore conflict, and to apply this information toward locally-based conservations actions, we conducted gender-stratified interviews and participatory mapping sessions with 378 people in 16 villages near two ecologically isolated protected areas in Kenya: Lake Nakuru National Park and Soysambu Conservancy. Specifically, we developed a method for associating interview responses and demographic information with spatial participatory data to examine how local perceptions of conflict compared to spatially-explicit records of livestock depredation in the region from 2010 to 2018. We mapped kernel densities of recorded and perceived risk of human-carnivore conflict and then tested for potential social and ecological predictors of divergences found between the two datasets. Mismatched hotspots of observed and perceived risk of conflict were correlated with several ecological and socioeconomic factors. Regions with higher NDVI exhibited more perceived conflict, while the opposite held true for verified conflict. Road density was positively correlated with both types of conflict, and both types of conflict increased closer to protected areas. Livestock ownership, visitation to Lake Nakuru National Park, if the participant's child walked to school, and male gender identity were associated with more perceived conflict reports. Education level and national park visitation were associated with more positive attitudes toward carnivores. Our results show that while observed and perceived conflict may ultimately be equally important for understanding and managing human-carnivore conflict, they may be driven by markedly different social and ecological processes. We suggest that integrating the spatially explicit experiences and perspectives of local communities with more traditional ecological methods is critical to identifying lasting and socially just forms of conflict mitigation.

Drought, desertification and poverty: A geospatial analysis of snakebite envenoming in the Caatinga biome of Brazil

Epidemiological data on snakebite in the Brazilian state of Ceará are scarce, as the only report on this subject was last published in 1997. However, according to the Brazilian system of recording disease incidents (Sistema de Informação de Agravos de Notificação [SINAN]), more than 13,000 snakebites have been registered since 2001 in the state of Ceará, making this disease an important public health issue. In the present study, we evaluate the influence of environmental changes, including drought and desertification, on the risk of snakebite envenoming in the Brazilian northeastern state of Ceará. We compare public data on snakebites from Brazilian Epidemiological Surveillance System (DATASUS), rainfall records, advanced desertification maps, pastures and socioeconomic information of the 184 municipals in Ceará between 2001 and 2017. During the period of investigation, 8,945 snakebites were recorded, the majority (93.8%) of which involved venomous snakes. Almost half of the municipals (48%) had 100 incidences or more per 100,000 inhabitants. Data collected also highlight month-to-month occurrences of snakebites, with trends to rise shortly after the onset of precipitation, peaking in July and then trending downward as rainfall decreases, reaching the lowest level in December. We deduce an inverse relationship between Human Development Index (HDI) and snakebites per area. Spearman correlation and principal component analysis support the hypothesis that water scarcity and desertification are linked to increased risk of snakebite envenoming. Our study indicates that besides poverty, dry and desertified areas represent risk factors associated with increased incidence of snakebite envenoming in the state of Ceará.

The Shrinking Resource Base of Pastoralism: Saami Reindeer Husbandry in a Climate of Change

The productive performance of large ungulates in extensive pastoral grazing systems is modulated simultaneously by the effects of climate change and human intervention independent of climate change. The latter includes the expansion of private, civil and military activity and infrastructure and the erosion of land rights. We used Saami reindeer husbandry in Norway as a model in which to examine trends in, and to compare the influence of, both effects on a pastoral grazing system. Downscaled projections of mean annual temperature over the principal winter pasture area (Finnmarksvidda) closely matched empirical observations across 34 years to 2018. The area, therefore, is not only warming but seems likely to continue to do so. Warming notwithstanding, 50-year (1969–2018) records of local weather (temperature, precipitation and characteristics of the snowpack) demonstrate considerable annual and decadal variation which also seems likely to continue and alternately to amplify and to counter net warming. Warming, moreover, has both positive and negative effects on ecosystem services that influence reindeer. The effects of climate change on reindeer pastoralism are evidently neither temporally nor spatially uniform, nor indeed is the role of climate change as a driver of change in pastoralism even clear. The effects of human intervention on the system, by contrast, are clear and largely negative. Gradual liberalization of grazing rights from the 18th Century has been countered by extensive loss of reindeer pasture. Access to ~50% of traditional winter pasture was lost in the 19th Century owing to the closure of international borders to the passage of herders and their reindeer. Subsequent to this the area of undisturbed pasture within Norway has decreased by 71%. Loss of pasture due to piecemeal development of infrastructure and to administrative encroachment that erodes herders' freedom of action on the land that remains to them, are the principal threats to reindeer husbandry in Norway today. These tangible effects far exceed the putative effects of current climate change on the system. The situation confronting Saami reindeer pastoralism is not unique: loss of pasture and administrative, economic, legal and social constraints bedevil extensive pastoral grazing systems across the globe.

The plasticity of ungulate migration in a changing world

Migratory ungulates are thought to be declining globally because their dependence on large landscapes renders them highly vulnerable to environmental change. Yet recent studies reveal that many ungulate species can adjust their migration propensity in response to changing environmental conditions to potentially improve population persistence. In addition to the question of whether to migrate, decisions of where and when to migrate appear equally fundamental to individual migration tactics, but these three dimensions of plasticity have rarely been explored together. Here, we expand the concept of migratory plasticity beyond individual switches in migration propensity to also include spatial and temporal adjustments to migration patterns. We develop a novel typological framework that delineates every potential change type within the three dimensions, then use this framework to guide a literature review. We discuss broad patterns in migratory plasticity, potential drivers of migration change, and research gaps in the current understanding of this trait. Our result reveals 127 migration change events in direct response to natural and human-induced environmental changes across 27 ungulate species. Species that appeared in multiple studies showed multiple types of change, with some exhibiting the full spectrum of migratory plasticity. This result highlights that multidimensional migratory plasticity is pervasive in ungulates, even as the manifestation of plasticity varies case by case. However, studies thus far have rarely been able to determine the fitness outcomes of different types of migration change, likely due to the scarcity of long-term individual-based demographic monitoring as well as measurements encompassing a full behavioral continuum and environmental gradient for any given species. Recognizing and documenting the full spectrum of migratory plasticity marks the first step for the field of migration ecology to employ quantitative methods, such as reaction norms, to predict migration change along environmental gradients. Closer monitoring for changes in migratory propensity, routes, and timing may improve the efficacy of conservation strategies and management actions in a rapidly changing world.

Genetic and demographic history define a conservation strategy for earth's most endangered pinniped, the Mediterranean monk seal Monachus monachus

The Mediterranean monk seal (Monachus monachus) is a flagship species for marine conservation, but important aspects of its life history remain unknown. Concerns over imminent extinction motivated a nuclear DNA study of the species in its largest continuous subpopulation in the eastern Mediterranean Sea. Despite recent evidence of partial subpopulation recovery, we demonstrate that there is no reason for complacency, as the species still shares several traits that are characteristic of a critically endangered species: Mediterranean monk seals in the eastern Mediterranean survive in three isolated and genetically depauperate population clusters, with small effective population sizes and high levels of inbreeding. Our results indicated male philopatry over short distances, which is unexpected for a polygynous mammal. Such a pattern may be explained by the species' unique breeding behavior, in which males defend aquatic territories near breeding sites, while females are often forced to search for new pupping areas. Immediate action is necessary to reverse the downward spiral of population decline, inbreeding accumulation and loss of genetic diversity. We propose concrete conservation measures for the Mediterranean monk seal focusing on reducing anthropogenic threats, increasing the population size and genetic diversity, and thus improving the long-term prospects of survival.

Fence Ecology: Frameworks for Understanding the Ecological Effects of Fences

Investigations of the links between human infrastructure and ecological change have provided eye-opening insights into humanity's environmental impacts and contributed to global environmental policies. Fences are globally ubiquitous, yet they are often omitted from discussions of anthropogenic impacts. In the present article, we address this gap through a systematic literature review on the ecological effects of fences. Our overview provides five major takeaways: 1) an operational definition of fencing to structure future research, 2) an estimate of fence densities in the western United States to emphasize the challenges of accounting for fences in human-footprint mapping, 3) a framework exhibiting the ecological winners and losers that fences produce, 4) a typology of fence effects across ecological scales to guide research, and 5) a summary of research trends and biases that suggest that fence effects have been underestimated. Through highlighting past research and offering frameworks for the future, we aim with this work to formalize the nascent field of fence ecology.

Methods for Monitoring Large Terrestrial Animals in the Wild

Reliable information about wildlife is absolutely important for making informed management decisions. The issues with the effectiveness of the control and monitoring of both large and small wild animals are relevant to assess and protect the world’s biodiversity. Monitoring becomes part of the methods in wildlife ecology for observation, assessment, and forecasting of the human environment. World practice reveals the potential of the joint application of both proven traditional and modern technologies using specialized equipment to organize environmental control and management processes. Monitoring large terrestrial animals require an individual approach due to their low density and larger habitat. Elk/moose are such animals. This work aims to evaluate the methods for monitoring large wild animals, suitable for controlling the number of elk/moose in the framework of nature conservation activities. Using different models allows determining the population size without affecting the animals and without significant financial costs. Although, the accuracy of each model is determined by its postulates implementation and initial conditions that need statistical data. Depending on the geographical, climatic, and economic conditions in each territory, it is possible to use different tools and equipment (e.g., cameras, GPS sensors, and unmanned aerial vehicles), a flexible variation of which will allow reaching the golden mean between the desires and capabilities of researchers.

Spatio-Temporal Changes in Wildlife Habitat Quality in the Greater Serengeti Ecosystem

Understanding habitat quality and its dynamics is imperative for maintaining healthy wildlife populations and ecosystems. We mapped and evaluated changes in habitat quality (1975–2015) in the Greater Serengeti Ecosystem of northern Tanzania using the Integrated Valuation of Environmental Services and Tradeoffs (InVEST) model. This is the first habitat quality assessment of its kind for this ecosystem. We characterized changes in habitat quality in the ecosystem and in a 30 kilometer buffer area. Four habitat quality classes (poor, low, medium and high) were identified and their coverage quantified. Overall (1975–2015), habitat quality declined over time but at rates that were higher for habitats with lower protection level or lower initial quality. As a result, habitat quality deteriorated the most in the unprotected and human-dominated buffer area surrounding the ecosystem, at intermediate rates in the less heavily protected Wildlife Management Areas, Game Controlled Areas, Game Reserves and the Ngorongoro Conservation Area and the least in the most heavily protected Serengeti National Park. The deterioration in habitat quality over time was attributed primarily to anthropogenic activities and major land use policy changes. Effective implementation of land use plans, robust and far-sighted institutional arrangements, adaptive legal and policy instruments are essential to sustaining high habitat quality in contexts of rapid human population growth.

Herbivore corridors sustain genetic footprint in plant populations: a case for Spanish drove roads

Habitat fragmentation is one of the greatest threats to biodiversity conservation and ecosystem productivity mediated by direct human impact. Its consequences include genetic depauperation, comprising phenomena such as inbreeding depression or reduction in genetic diversity. While the capacity of wild and domestic herbivores to sustain long-distance seed dispersal has been proven, the impact of herbivore corridors in plant population genetics remains to be observed. We conducted this study in the Conquense Drove Road in Spain, where sustained use by livestock over centuries has involved transhumant herds passing twice a year en route to winter and summer pastures. We compared genetic diversity and inbreeding coefficients of Plantago lagopus populations along the drove road with populations in the surrounding agricultural matrix, at varying distances from human settlements. We observed significant differences in coefficients of inbreeding between the drove road and the agricultural matrix, as well as significant trends indicative of higher genetic diversity and population nestedness around human settlements. Trends for higher genetic diversity along drove roads may be present, although they were only marginally significant due to the available sample size. Our results illustrate a functional landscape with human settlements as dispersal hotspots, while the findings along the drove road confirm its role as a pollinator reservoir observed in other studies. Drove roads may possibly also function as linear structures that facilitate long-distance dispersal across the agricultural matrix, while local P. lagopus populations depend rather on short-distance seed dispersal. These results highlight the role of herbivore corridors for conserving the migration capacity of plants, and contribute towards understanding the role of seed dispersal and the spread of invasive species related to human activities.

Cross-boundary human impacts compromise the Serengeti-Mara ecosystem

Protected areas provide major benefits for humans in the form of ecosystem services, but landscape degradation by human activity at their edges may compromise their ecological functioning. Using multiple lines of evidence from 40 years of research in the Serengeti-Mara ecosystem, we find that such edge degradation has effectively “squeezed” wildlife into the core protected area and has altered the ecosystem’s dynamics even within this 40,000-square-kilometer ecosystem. This spatial cascade reduced resilience in the core and was mediated by the movement of grazers, which reduced grass fuel and fires, weakened the capacity of soils to sequester nutrients and carbon, and decreased the responsiveness of primary production to rainfall. Similar effects in other protected ecosystems worldwide may require rethinking of natural resource management outside protected areas.

Fencing bodes a rapid collapse of the unique Greater Mara ecosystem

With land privatization and fencing of thousands of hectares of communal grazing areas, East Africa is struggling with one of the most radical cultural and environmental changes in its history. The 668,500-hectare Greater Mara is of crucial importance for the great migrations of large mammals and for Maasai pastoralist culture. However, the magnitude and pace of these fencing processes in this area are almost completely unknown. We provide new evidence that fencing is appropriating land in this area at an unprecedented and accelerating speed and scale. By means of a mapped series of multispectral satellite imagery (1985-2016), we found that in the conservancies with the most fences, areal cover of fenced areas has increased with >20% since 2010. This has resulted in a situation where fencing is rapidly increasing across the Greater Mara, threatening to lead to the collapse of the entire ecosystem in the near future. Our results suggest that fencing is currently instantiating itself as a new permanent self-reinforcing process and is about to reach a critical point after which it is likely to amplify at an even quicker pace, incompatible with the region's role in the great wildebeest migration, wildlife generally, as well as traditional Maasai pastoralism.