Response of pumas (Puma concolor) to migration of their primary prey in Patagonia

The significance of partial migration for food web and ecosystem dynamics

Migration is ubiquitous and can strongly shape food webs and ecosystems. Less familiar, however, is that the majority of life cycle, seasonal and diel migrations in nature are partial migrations: only a fraction of the population migrates while the other individuals remain in their resident ecosystem. Here, we demonstrate different impacts of partial migration rendering it fundamental to our understanding of the significance of migration for food web and ecosystem dynamics. First, partial migration affects the spatiotemporal distribution of individuals and the food web and ecosystem-level processes they drive differently than expected under full migration. Second, whether an individual migrates or not is regularly correlated with morphological, physiological, and/or behavioural traits that shape its food-web and ecosystem-level impacts. Third, food web and ecosystem dynamics can drive the fraction of the population migrating, enabling the potential for feedbacks between the causes and consequences of migration within and across ecosystems. These impacts, individually and in combination, can yield unintuitive effects of migration and drive the dynamics, diversity and functions of ecosystems. By presenting the first full integration of partial migration and trophic (meta-)community and (meta-)ecosystem ecology, we provide a roadmap for studying how migration affects and is affected by ecosystem dynamics in a changing world.

Phenological drivers of ungulate migration in South America: characterizing the movement and seasonal habitat use of guanacos

BACKGROUND

Migration is a widespread strategy among ungulates to cope with seasonality. Phenology, especially in seasonally snow-covered landscapes featuring "white waves" of snow accumulation and "green waves" of plant green-up, is a phenomenon that many migratory ungulates navigate. Guanacos (Lama guanicoe) are native camelids to South America and might be the last ungulate in South America that migrates. However, a detailed description of guanacos´ migratory attributes, including whether they surf or jump phenological waves is lacking.

METHODS

We quantified the migratory movements of 21 adult guanacos over three years in Patagonia, Argentina. We analyzed annual movement patterns using net squared displacement (NSD) and home range overlap and quantified snow and vegetation phenology via remotely sensed products.

RESULTS

We found that 74% of the individual guanacos exhibited altitudinal migrations. For migratory guanacos, we observed fidelity of migratory ranges and residence time, but flexibility around migration propensity, timing, and duration of migration. The scarce vegetation and arid conditions within our study area seemed to prevent guanacos from surfing green waves; instead, guanacos appeared to avoid white waves.

CONCLUSION

Our study shows that guanaco elevational migration is driven by a combination of vegetation availability and snow cover, reveals behavioral plasticity of their migration, and highlights the importance of snow phenology as a driver of ungulate migrations.

Loss of Migratory Traditions Makes the Endangered Patagonian Huemul Deer a Year-Round Refugee in Its Summer Habitat

The huemul (Hippocamelus bisulcus) is endangered, with 1500 deer split into >100 subpopulations along 2000 km of Andes. Currently occupied areas are claimed-erroneously, to be critical prime habitats. We analyzed historical spatiotemporal behavior since current patterns represent only a fraction of pre-Columbian ones. Given the limited knowledge, the first group (n = 6) in Argentina was radio-marked to examine spatial behavior. Historically, huemul resided year-round in winter ranges, while some migrated seasonally, some using grasslands >200 km east of their current presence, reaching the Atlantic. Moreover, huemul anatomy is adapted to open unforested habitats, also corroborated by spotless fawns. Extreme naivety towards humans resulted in early extirpation on many winter ranges—preferentially occupied by humans, resulting in refugee huemul on surrounding mountain summer ranges. Radio-marked huemul remained in small ranges with minimal altitudinal movements, as known from other subpopulations. However, these resident areas documented here are typical summer ranges as evidenced by past migrations, and current usage for livestock. The huemul is the only cervid known to use mountain summer ranges year-round in reaction to anthropogenic activities. Losing migratory traditions is a major threat, and may explain their presently prevalent skeletal diseases, reduced longevity, and lacking recolonizations for most remaining huemul subpopulations.

The Humpty Dumpty Effect on Planet Earth

Humans have treated the earth harshly. Degradation of extant ecosystems leaves little chance that they might function as they have in the past. Putting back the pieces and restoring what once existed is no longer possible even with re-wildling—an effect analogous to the Humpty Dumpty parable. However, we do have conservation successes after concerted efforts related to habitat protection, species and ecosystem restoration, and planning. While the changes to Earth's biosphere are grave, necessitating immediate and exhaustive action, our Humpty Dumpty world reassembles with progressive conservation victories at all regional scales from local to global which should lead to a modicum of optimism rather than despair. We suggest that to be truly effective our work as academic scientists must be more than publishing in scholarly journals. At the least, this should include changes in how success is measured in science and how university tenure is awarded.

Daily activity pattern of pumas (Puma concolor) and their potential prey in a tropical cloud forest of Colombia

Ecosystems in the northern Andes face unprecedented habitat loss. Pumas are the top predators in the region and exert key ecological functions, such as population control and resource facilitation. However, little is known about the temporal niche of the species or its effects on behaviour of prey in the tropics. We hypothesized that there is a link between the activity patterns of pumas and their prey in a cloud forest of the Central Andes of Colombia. We installed 61 camera traps to estimate the degree of overlap between the daily activity curves of pumas and seven potential prey species, using conditional kernel density functions. Pumas, armadillos, mountain pacas, and white–eared opossums were mainly nocturnal, with little crepuscular activity and high temporal overlap. Central American agouti, mountain coati, little red brocket deer, and Cauca guan displayed a predominantly diurnal activity and temporal partitioning with pumas. As opportunistic predators, pumas were able to maximize foraging efficiency by preying on the crepuscular and nocturnal species. Conservation of this highland predator will largely depend on the suitable management of its native prey.

Puma (Puma concolor) in the Neighborhood? Records Near Human Settlements and Insights into Human-Carnivore Coexistence in Central Chile

Simple Summary

The presence of carnivores near human settlements is a poorly studied topic that generates concern and perception of risk in some human communities, especially for medium to large felids. Apart from the conflict of the potential predation of livestock, there is the insecurity perception of a potential attack on people. To gain a better understanding of how, when, and how close pumas approached human settlements, we analyze 51 puma records near populated areas over eight years in central Chile. The results show that pumas approached human-populated areas; in 23.5% of the records pumas are found between 0 and 999 m from the nearest human settlement, 25.5% are between 1000 and 4999 m, and 51% are over 5000 m. We associate puma records with landscape features, such as mountain ranges, land-use, road, and urban infrastructure; and based on previous knowledge of puma biology, behavior, and habitat preference, we identify their area of occupation and the potential biological corridor used for their movements from the Andes Range to the coast. Our results show the adaptability of pumas to human-dominated landscapes, and their capacity to overcome landscape barriers, such as human infrastructure, contributing to a better understanding of the population dynamics in the study area. Studies on human–carnivore coexistence, through formulas that consider local realities and the reduction of implicit risks for humans, are urgently needed, both globally and locally, and likely the only way to secure the long-term conservation of pumas in human-dominated landscapes.

Abstract

The wildland–urban interface lies at the confluence of human-dominated and wild landscapes—creating a number of management and conservation challenges. Wildlife sightings near human settlements have appeared to increase in the last years. This article reports 51 records of presences, sightings, and livestock attacks of Puma concolor, a large-sized felid, collected from 2012 to 2020 across the O’Higgins region in central Chile. Puma records were concentrated in the east of the region in the Andes Range and foothills (90%). The number of puma records is higher in the last four to six years than in previously studied years. Of the 51 records, 23.5% are between 0 and 999 m from the nearest human settlement (classified as very close), 25.5% are between 1000 and 4999 m (moderately close), and 51% are over 5000 m (distant). Most of the sightings are recorded in the summer (35%) and spring (29%). We identify an area of approximately 9000 km² of suitable habitat as the most probable corridor effectively connecting pumas moving between eastern and western areas, encompassing the Angostura de Paine mountain range. Our results contribute to the understanding of the presence and movements of P. concolor near urban areas and human settlements, confirming their persistence in and adaptation to human-dominated landscapes. We also provide insights into human–carnivore coexistence in the current global context in the densely populated central Chile.

Exotic Prey Facilitate Coexistence between Pumas and Culpeo Foxes in the Andes of Central Chile

Coexistence between species with similar ecological niches implies species must segregate along one or more niche axes to survive. Space, time, and trophic resources are regarded as the principal axes upon which species segregate. We examined segregation along these niche axes to determine mechanisms underlying coexistence between the two main predators, puma (Puma concolor) and culpeo foxes (Lycalopex culpaeus) in the Andes of Central Chile. We used occupancy modeling to examine space use and overlap, Kernel Density Estimation to determine temporal activity patterns and overlap, and analysis of prey remains in feces to assess diet breadth and similarity. We found high spatial overlap and positive associations between detection of the carnivores lending little support for spatial segregation. Similarly, we found high nocturnal, temporal overlap between pumas and foxes that matched peaks in activity of prey. In contrast, we found relatively low dietary overlap indicating niche segregation likely occurs along the dietary axis. The Puma diet was dominated by introduced, exotic hares and foxes appeared to shift away from hares to rabbits, small mammals, and seeds. Given that lagomorphs are the main dietary resource for pumas in particular, management decisions regarding the control or eradication of such exotic species could negatively affected puma survival.

Zooming in on mechanistic predator-prey ecology: Integrating camera traps with experimental methods to reveal the drivers of ecological interactions

Camera trap technology has galvanized the study of predator-prey ecology in wild animal communities by expanding the scale and diversity of predator-prey interactions that can be analysed. While observational data from systematic camera arrays have informed inferences on the spatiotemporal outcomes of predator-prey interactions, the capacity for observational studies to identify mechanistic drivers of species interactions is limited. Experimental study designs that utilize camera traps uniquely allow for testing hypothesized mechanisms that drive predator and prey behaviour, incorporating environmental realism not possible in the laboratory while benefiting from the distinct capacity of camera traps to generate large datasets from multiple species with minimal observer interference. However, such pairings of camera traps with experimental methods remain underutilized. We review recent advances in the experimental application of camera traps to investigate fundamental mechanisms underlying predator-prey ecology and present a conceptual guide for designing experimental camera trap studies. Only 9% of camera trap studies on predator-prey ecology in our review use experimental methods, but the application of experimental approaches is increasing. To illustrate the utility of camera trap-based experiments using a case study, we propose a study design that integrates observational and experimental techniques to test a perennial question in predator-prey ecology: how prey balance foraging and safety, as formalized by the risk allocation hypothesis. We discuss applications of camera trap-based experiments to evaluate the diversity of anthropogenic influences on wildlife communities globally. Finally, we review challenges to conducting experimental camera trap studies. Experimental camera trap studies have already begun to play an important role in understanding the predator-prey ecology of free-living animals, and such methods will become increasingly critical to quantifying drivers of community interactions in a rapidly changing world. We recommend increased application of experimental methods in the study of predator and prey responses to humans, synanthropic and invasive species, and other anthropogenic disturbances.

Fragmentation and low density as major conservation challenges for the southernmost populations of the European wildcat

Knowledge of population dynamics of threatened species in the wild is key to effective conservation actions. However, at present, there are many examples of endangered animals for which their current situation is unknown, and not just in remote areas and less developed countries. We have explored this topic by studying the paradigmatic case of the European wildcat (Felis silvestris silvestris), an endangered small carnivore whose status has been subjectively established on the basis of non-systematic approaches and opportunistic records. Little is known about its demographic situation, prompting the need for information to improve conservation measures. However, the secretive behaviour of felines along with its low density in natural conditions have prevented the gathering of sufficient data. We developed a field sampling strategy for one of the largest populations (Andalusia, South Spain, 87,268 km2), based on a logistically viable systematic non-intrusive survey by camera-trapping. This study offers the first large-scale estimation for any European wildcat population, based on analytical approaches applied on Species Distribution Models. A hierarchical approach based on a Maxent model for distribution estimation was used, along with Generalised Linear Models for density estimation from explicit spatial capture-recapture data. Our results show that the distribution range is smaller and more highly fragmented than previously assumed. The overall estimated density was very low (0.069 ±0.0019 wildcats/km2) and the protected areas network seems to be insufficient to cover a significant part of the population or a viable nucleus in demographic terms. Indeed, the most important areas remain unprotected. Our main recommendations are to improve the protected area network and/or vigilance programs in hunting estates, in addition to studying and improving connectivity between the main population patches.