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Ricardo Baldi

Centro Nacional Patagónico CONICET, IPEEC, Senior Researcher

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Universidad Autónoma de Madrid

Meredith Root-Bernstein

Aarhus University

National Scientific and Technical Research Council

Jonathan Dombrosky

Nicolás Fuentes

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Claudio A Moraga

University of Florida

Universidad de La Serena-Chile

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Papers by Ricardo Baldi

Scientific evidence does not support the translocation of guanacos in Argentina

Conservation Science and Practice, 2023

The Argentinian Ministry of Environment has approved the translocation of 45 guanacos from Southe... more The Argentinian Ministry of Environment has approved the translocation of 45 guanacos from Southern Patagonia to the Pampas region, a distance of 1500 km, as the initial phase toward future translocations into a National Park located in the Chaco region, another 1600 km further North. This decision raises concerns about the technical and ethical aspects of the translocation. Firstly, there is a lack of proper evaluation and scientific evidence to support the need, opportunity, and feasibility of this translocation. The guanaco population is currently over one million and is increasing, and genetic differences exist among local populations. The translocation could produce anthropogenic‐driven admixed populations, leading to genetic swamping and disrupting evolutionary processes. Second, there are ethical conflicts around managing
wild species populations that prioritize private objectives and disregard local, publicly funded science. Rewilding projects require a deep understanding of interacting ecosystem processes, and of the socio‐economic context. This management decision violates guiding principles for rewilding and should have followed proper scientific evaluation and transparent local consultation.

Past and Recent Effects of Livestock Activity on the Genetic Diversity and Population Structure of Native Guanaco Populations of Arid Patagonia

Animals, 2021

Determining the impacts of human activities on natural populations is important for biodiversity ... more Determining the impacts of human activities on natural populations is important for biodiversity conservation. In this paper, we study the past and more recent effects of urbanization and livestock activity on the genetic diversity and population structure of endemic guanaco
populations of the arid Monte and Patagonian Steppe of central Argentina. Our results reveal that urbanization, the installation of fences, and the competition from sheep grazing coincided with the isolation of several guanaco populations, especially in areas with the highest intensity of livestock activity. However, our genetic analyses suggest that a more recent increase in connectivity among groups is occurring. Our results highlight the importance of implementing conservation management
plans for natural populations in arid and human-intervened environments.

POTENTIAL CONTRIBUTIONS OF MAMMALS TO HUMAN WELL-BEING IN ARGENTINA

by Ricardo Baldi and anahi formoso

Mastozoología Neotropical, 2022

Mammals are key components of biodiversity mediating ecosystem functions, mainly because of the d... more Mammals are key components of biodiversity mediating ecosystem functions, mainly because of the diversity of forms and functions of this group. Understanding and making explicit the role of mammals underpinning Nature’s Contributions to People (NCP) or directly contributing to human well-being would help to inuence policy formulation towards sustainable development and nature conservation. Through a workshop held at the XXXII Jornadas Argentinas de Mastozoología and subsequent collaborative work, we compiled information related to Mammal’s Contributions to People in Argentina (MCP-Arg) based on participants’ interpretation of the available literature and their eld experience. Argentinian mammals contribute to 12 of the 18 dened NCPs. We derived numerous MCP-Arg from studies that focused mainly on ecological processes and conservation, revealing an information gap in MCP-Arg description, quantication, and mapping. All taxa contribute similarly to the overall contributions, highlighting the importance of preserving mammal diversity. Conservation should also be framed at the local community rather than regional scales, aiming to preserve ecological functioning and contributions to human well-being, especially within regulation contributions. Our results show destructive feedback between threats and habitat-related contributions, with habitat degradation being the greatest threat to mammalian contributions and habitat maintenance the most threatened one. Our research indicates that a substantial amount of knowledge about MCP-Arg is available through narratives and interpretations. Considering the NCP approach to mammalian research, we can make signicant contributions to both mammal conservation and human well-being

The Status of the World’s Land and Marine Mammals: Diversity, Threat, and Knowledge

Science, 2008

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomical... more Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world’s mammals. Data, compiled by 1700+ experts, cover all 5487 species,
including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific
developments and conservation action.

Abundance Estimates of the Lesser Rhea Rhea pennata pennata in the Argentine Patagonia: Conservation Implications

Frontiers in Ecology and Evolution, 2015

Living on the edge: Heterogeneity in vegetation type cover as key factor of the habitat occupied by Dolichotis patagonum at landscape scale

Journal of Arid Envirinments, 2017

There is an urgent need to characterize the relationships between endangered species and their ha... more There is an urgent need to characterize the relationships between endangered species and their habitats in response to the accelerating pace of habitat transformation by humans. Mara (Dolichotis patagonum) is a large rodent endemic to the Argentine semi-deserts. It has been classified as "Near Threatened" by IUCN mainly as the result of habitat loss. There is contradictory evidence about the impact of human activities on mara and further information is needed to develop effective conservation strategies. We describe the main environmental factors, both natural and human, that are associated with warren presence as an indicator of the habitat selected by maras at the landscape scale. Habitat selected by maras was characterized by a high proportion of bare soil, low b diversity, open herbaceous steppe, and proximity to fences. The relationship of warren presence to the proportion of shrubby steppe in the broader landscape was variable across environments being positive in grasslands, and negative in shrubbier habitats. This supports the hypothesis that mara's preference for open areas depends on the level of shrubs in the surrounding habitat. As a result, conservation efforts will need to be tailored to the amount and structure of vegetation in any given area.

Breeding success of the endemic mara Dolichotis patagonum in relation to habitat selection: Conservation implications

Journal of Arid Environments, 2007

Although maras (Dolichotis patagonum) are among the most representative mammals of South America,... more Although maras (Dolichotis patagonum) are among the most representative mammals of South America, knowledge on the ecological processes affecting their conservation is scarce. In particular, the study of habitat requirements and its relationship with breeding success is necessary to identify possible threats and develop conservation action for this endemic mammal. I investigated habitat selection patterns by maras and their relationship with breeding success in Penı´nsula Valde´s, Argentine Patagonia. Maras bred from mid-August to late December, and they tended to build the breeding warrens in open, grass-dominated habitats more than expected while avoided closed habitats dominated by taller shrubs. Mean number of breeding adults per warren was 4.26, while mean number of pups born per warren was 4.46. Overall, 30 (45%) of 67 pups survived until the 6th week of life, but pups born in warrens located in open habitats survived significantly better than pups born in warrens located in closed habitats (50% vs. 30% of the pups born). As grass-dominated areas uphold the highest densities of domestic sheep and habitat modification due to overgrazing is a widespread process across arid Patagonia, effects on the availability of suitable breeding sites for maras are likely to occur and require further investigation. r

Analysis of the spatial variation in the abundance of lesser rheas using density surface models

by Ricardo Baldi and Romina D'Agostino

Wildlife Research, 2018

Context. The study of the spatial variation in abundance of wild populations and the identificati... more Context. The study of the spatial variation in abundance of wild populations and the identification of factors explaining the observed patterns are key both to understand aspects of basic ecology and the effects of human activities. This is usually difficult to evaluate for low-density and widely distributed species, such as the lesser rhea (Rhea pennata pennata), an endemic bird from South America. Recent advances in spatial modelling such as the density surface models (DSM) combine distance-sampling procedures with modelling techniques to produce maps of spatial variation in abundance, and its relationship with predictive variables.

Modeling the spatial structure of the endemic mara (Dolichotis patagonum) across modified landscapes

PeerJ, 2019

Across modified landscapes, anthropic factors can affect habitat selection by animals and consequ... more Across modified landscapes, anthropic factors can affect habitat selection by animals and consequently their abundance and distribution patterns. The study of the spatial structure of wild populations is crucial to gain knowledge on species' response to habitat quality, and a key for the design and implementation of conservation actions. This is particularly important for a low-density and widely distributed species such as the mara (Dolichotis patagonum), a large rodent endemic to Argentina across the Monte and Patagonian drylands where extensive sheep ranching predominates. We aimed to assess the spatial variation in the abundance of maras and to identify the natural and anthropic factors influencing the observed patterns in Península Valdés, a representative landscape of Patagonia. We conducted ground surveys during the austral autumn from 2015 to 2017. We built density surface models to account for the variation in mara abundance, and obtained a map of mara density at a resolution of four km 2 . We estimated an overall density of 0.93 maras.km -2 for the prediction area of 3,476 km 2 . The location of ranch buildings, indicators of human presence, had a strong positive effect on the abundance of maras, while the significant contribution of the geographic longitude suggested that mara density increases with higher rainfall. Although human presence favored mara abundance, presumably by providing protection against predators, it is likely that the association could bring negative consequences for maras and other species. The use of spatial models allowed us to provide the first estimate of mara abundance at a landscape scale and its spatial variation at a high resolution. Our approach can contribute to the assessment of mara population abundance and the factors shaping its spatial structure elsewhere across the species range, all crucial attributes to identify and prioritize conservation actions.

Choosing what is left. The spatial structure of a wild herbivore population within a livestock dominated landscape

PeerJ, 2020

Shrublands and grasslands comprise over 30% of the land surface and are among the most exploited ... more Shrublands and grasslands comprise over 30% of the land surface and are among the most exploited ecosystems for livestock production. Across natural landscapes, the distribution and abundance of wild herbivores are affected by interspecific competition for foraging resources, hunting and the development of infrastructure among other factors. In Argentine Patagonia, the abundance of domestic sheep grazing on native vegetation outnumbers the widely distributed guanaco (Lama guanicoe) and sheep ranching monopolizes the most productive lands. In this work, we aimed to assess the spatial variation in the abundance of guanacos in Península Valdés, a representative landscape of Patagonia, investigating the incidence of natural and human-related factors. We conducted ground surveys during the austral autumn in 2017 totaling 383.4 km along areas with and without sheep ranching. We built density surface models to account for the variation in guanaco abundance and obtained a map of guanaco density at a resolution of 4 km2. We estimated an overall density of 11.71 guanacos.km−2 for a prediction area of 3,196 km2, although the density of guanacos tripled in areas where sheep ranching was terminated
(in around 20% of the surface of Península Valdés) compared to areas with
sheep. Guanacos were more abundant at lower values of primary productivity
and sheep stocking rates and further from inhabited ranch buildings, suggesting competition with sheep and conflict with humans. Although guanacos selected open, grass-dominated habitats across sheep-free sites, fences dividing properties and paddocks played a significant role in the spatial structure of their population in Península Valdés affecting negatively the abundance of guanacos. Our results indicate that actions to improve habitat connectivity for guanacos, favor the coexistence among guanacos and sheep ranching, and promote responsible
human activities and attitudes towards wildlife are needed.

The impact of conservation on the status of the world's vertebrates

Science (New York, N.Y.), Jan 10, 2010

Ecological drivers of guanaco recruitment: variable carrying capacity and density dependence

Oecologia, 2014

fluctuates in response to climatic variation, and that these fluctuations have relevant consequen... more fluctuates in response to climatic variation, and that these fluctuations have relevant consequences for herbivore dynamics, such as amplifying density dependence in drier years. We conclude that including the coupling between environmental variability in resources and density dependence is crucial to model ungulate population dynamics; to overlook temporal changes in carrying capacity may even mask density dependence as well as other important processes.

Ecological Correlates of Group-Size Variation in a Resource-Defense Ungulate, the Sedentary Guanaco

PLoS ONE, 2014

For large herbivores, predation-risk, habitat structure and population density are often reported... more For large herbivores, predation-risk, habitat structure and population density are often reported as major determinants of group size variation within and between species. However, whether the underlying causes of these relationships imply an ecological adaptation or are the result of a purely mechanistic process in which fusion and fragmentation events only depend on the rate of group meeting, is still under debate. The aim of this study was to model guanaco family and bachelor group sizes in contrasting ecological settings in order to test hypotheses regarding the adaptive significance of group-size variation. We surveyed guanaco group sizes within three wildlife reserves located in eastern Patagonia where guanacos occupy a mosaic of grasslands and shrublands. Two of these reserves have been free from predators for decades while in the third, pumas often prey on guanacos. All locations have experienced important changes in guanaco abundance throughout the study offering the opportunity to test for density effects. We found that bachelor group size increased with increasing density, as expected by the mechanistic approach, but was independent of habitat structure or predation risk. In contrast, the smaller and territorial family groups were larger in the predator-exposed than in the predator-free locations, and were larger in open grasslands than in shrublands. However, the influence of population density on these social units was very weak. Therefore, family group data supported the adaptive significance of group-size variation but did not support the mechanistic idea. Yet, the magnitude of the effects was small and between-population variation in family group size after controlling for habitat and predation was negligible, suggesting that plasticity of these social units is considerably low. Our results showed that different social units might respond differentially to local ecological conditions, supporting two contrasting hypotheses in a single species, and highlight the importance of taking into account the proximate interests and constraints to which group members may be exposed to when deriving predictions about group-size variation.

Response of guanacos Lama guanicoe to changes in land management in Península Valdés, Argentine Patagonia: conservation implications

Oryx, 2012

Response of guanacos Lama guanicoe to changes in land management in Península Valdé s, Argentine ... more Response of guanacos Lama guanicoe to changes in land management in Península Valdé s, Argentine Patagonia: conservation implications M a r í a V i r g i n i a B u r g i , A n d r e a M a r i n o , M a r í a V i c t o r i a R o d r í g u e z G u s t a v o P a z o s and R i c a r d o B a l d i Abstract The guanaco Lama guanicoe was the only large native herbivore widely distributed across Patagonia until the introduction of domestic sheep Ovis aries. Guanacos have declined because of competition with sheep for forage, high hunting pressure and habitat degradation. Península Valdés is a protected area where sheep ranching is the predominant activity. A ranch formerly dedicated to sheep production was converted into a private wildlife reserve, from which all the sheep were removed in 2005. We studied changes in guanaco abundance inside and outside the reserve after sheep removal, and also plant cover of various vegetation types. We found that guanaco abundance was higher inside than outside the reserve, and increased by three-fold within 3 years. Total plant cover and grass cover were higher inside than outside the reserve. Our results showed that guanacos reacted rapidly to changes in management, and suggest that even at a high density guanacos would not be as damaging to the vegetation as sheep. Although management changes resulted in significant changes in guanaco abundance locally, the size of a protected area influences the persistence of wild populations. A large herbivore such as the guanaco needs to be managed across large areas. We believe it is necessary to implement a management plan for Península Valdés that allows for the coexistence of sustainable livestock production and healthy wildlife populations.

Sex-related spatial patterns of Poa ligularis in relation to shrub patch occurrence in northern Patagonia

Journal of Vegetation Science, 2000

Poa ligularis is a dioecious species and a valuable forage plant which is widespread in the arid ... more Poa ligularis is a dioecious species and a valuable forage plant which is widespread in the arid steppe of northern Patagonia (Argentina). The vegetation in these areas consists of a system of perennial plant patches alternating with bare soil areas defining contrasting micro-environments. We hypothesized that (1) male and female individuals of P. ligularis are spatially segregated in different micro-environments, (2) the intensity of spatial segregation of sexes depends on plant structure and (3) spatial segregation of sexes is enhanced by competitive interactions between the sexes within the vegetation patches. We analysed the spatial distribution of female and male individuals in relation to the spatial pattern of vegetation in two areas differing in their vegetation structure. The location of P. ligularis within patches where either male, female or both sexes occurred was also analysed. The results indicate that different patterns of spatial distribution of sexes of P. ligularis may be found at the community level depending on the dominant life forms and geometric structure of plant patches. Where patches are of a lower height, with a high internal patch cover, individuals of both sexes are concentrated within patch canopies. In sites characterized by large, tall patches and less internal patch cover suitable microsites for female and male P. ligularis occur both within and outside the patch with males located at further distances from the patch edge. Where the patch is large and tall enough to allow the establishment of males and females at relatively high numbers, males occupy the patch periphery or even colonize the interpatch bare soil. These spatial patterns are consistent with selective traits in which females better tolerate intraspecific competition than males, while males tolerate wider fluctuations in the physical environment (soil moisture, nitrogen availability, wind intensity, etc.).

ABUNDANCIA Y DISTRIBUCIÓN DEL GUANACO (Lama guanicoe), EN EL NE DEL CHUBUT, PATAGONIA ARGENTINA

3 Fundación Patagonia Natural. Marcos A. Zar 760, (9120) Puerto Madryn, Chubut. TEL/FAX: (0965) 7... more

Social effects of space availability on the breeding behaviour of elephant seals in Patagonia

Animal Behaviour, 1996

The Patagonian breeding colony of southern elephant seals,Mirounga leonina, of Penı́nsula Valdés,... more The Patagonian breeding colony of southern elephant seals,Mirounga leonina, of Penı́nsula Valdés, Argentina is characterized by long, continuous, homogeneous and spacious beaches. Reproduction in this colony occurs at the lowest group densities reported for the species. The availability of ample space resulted in the dispersion of reproductive females along 160 km of coastline, with a range of 0–300 reproductive individuals per km. Females grouped together in small harems (median=11 females, range 2–122,N=432), and individual distance between females was one to two female body lengths. Body contact within the harem was rare. Consequently, agonistic interactions (AIs) between females and female aggression (Ag) towards alien pups occurred infrequently (median rate=4 AIs/female per 100 h and 1 Ag/pup per 100 h, respectively). Pup mortality rate was low for an elephant seal rookery (3.5% for 3487 pups). Most dead pups were stillborn, and only three of 38 pups whose cause of mortality could be determined died from trauma or starvation following mother–pup separation. Female dispersal allowed many males to have access to females. About 45% of all males of reproductive size in the colony (about 1000 individuals) had a harem. Most adult males mated with receptive females. Low-density breeding conditions benefited female reproductive success through an increase in pup survival. Female dispersal resulted in small harem size, however, and limited the potential for polygyny. 1996 The Association for the Study of Animal Behaviour

BREEDING BIOLOGY OF SOUTHERN ELEPHANT SEALS IN PATAGONIA

Marine Mammal Science, 1993

Abstract: Elephant seals breed in Patagonia (Península Valdés, Argentina) from late August to ear... more Abstract: Elephant seals breed in Patagonia (Península Valdés, Argentina) from late August to early November, reaching peak numbers during the first week in October. Observations of this population over the past ten years yielded similar results. Eighty percent of the pups were born by 2 October. Most (96%) of 663 females marked during three breeding seasons gave birth to a pup. Females stayed on land a mean of 28 d, gave birth 6 d after arrival, nursed their pups for 22 d, and copulated a mean of 2.5 times 20 d after parturition and 2 d before departure. Copulations peaked during the third week in October. Males spent 57–80 d on land fasting and defending harems of up to 134 females (median 11–13 females, depending on year). Most (96%) marked females that gave birth (n= 636) also weaned their pups successfully. Pup sex ratio was unity. Harems were smaller and breeding occurred about three weeks earlier in Patagonia than in other colonies. Thermal conditions, day length and food availability may explain clines in the timing of breeding events between populations, Other parameters of the breeding season for the expanding Patagonia colony are similar to those for declining southern elephant seal populations elsewhere.

Guanacos and sheep: evidence for continuing competition in arid Patagonia

Oecologia, 2001

Guanacos (Lama guanicoe) are the only wild ungulate species widely distributed across the Patagon... more Guanacos (Lama guanicoe) are the only wild ungulate species widely distributed across the Patagonian steppe and have undergone a precipitous population decline since the introduction of domestic sheep (Ovis aries) 100 years ago. There has been speculation that sheep ranching may have played a major role in guanaco population decline after monopolising the most productive land because of competition for forage plants. Our aim in this work was to estimate guanaco abundance and account for its variation across nine different sites, two seasons and two years. We conducted over 100 ground surveys of both guanacos and sheep and estimated the availability of the preferred plant species both animal species might select in their diet. We found that (1) sheep densities were up to 23 times higher than guanaco densities in sympatric conditions, (2) at a protected site without sheep, guanaco density was one order of magnitude higher than at the rest of the sites, (3) across nine different sites, sheep densities alone accounted for around 60% of the variation in guanaco abundance, (4) guanaco densities were negatively related to both total plant cover and availability of the preferred plant species in their diet, which were both positively associated with sheep density, and (5) within-site changes in guanaco densities between seasons and years were negatively related to changes in sheep densities. Our results are consistent with predictions on interspecific competition for food resources, although we cannot rule out possible effects of other human-related activities influencing guanaco abundance. We conclude that sheep compete with guanacos for forage in arid Patagonia.

HIGH POTENTIAL FOR COMPETITION BETWEEN GUANACOS AND SHEEP IN PATAGONIA

Journal of Wildlife Management, 2004

Guanacos (Lama guanicoe) are the largest native Artiodactyl in South America, and the most widely... more Guanacos (Lama guanicoe) are the largest native Artiodactyl in South America, and the most widely distributed. In arid Patagonia, densities are low and negatively related to domestic sheep numbers in space and time consistent with interspecific competition theory. Although guanacos and domestic sheep have been described as intermediate feeders sharing food resources, no studies have been conducted to compare their diets in sympatric conditions and explore whether the potential exists for direct interspecific competition. We assessed the diet of both species across 9 different sites and 2 seasons by microhistological analysis of fecal samples. We found that (1) guanacos and sheep are generalist herbivores feeding on a wide range of plant species; (2) both are intermediate feeders able to include both monocotyledoneous and dicotyledoneous plants in their diet; (3) both are able to change their diets seasonally; and (4) food niche overlap is high, particularly in summer when food resources are more scarce than in spring. We conclude that the potential for competition between guanacos and sheep is high and could have played a major role in the demise of guanacos. Consequently, current management practices focused on maximizing sheep numbers are not compatible with the recovery of guanaco populations.

Scientific evidence does not support the translocation of guanacos in Argentina

Conservation Science and Practice, 2023

The Argentinian Ministry of Environment has approved the translocation of 45 guanacos from Southe... more The Argentinian Ministry of Environment has approved the translocation of 45 guanacos from Southern Patagonia to the Pampas region, a distance of 1500 km, as the initial phase toward future translocations into a National Park located in the Chaco region, another 1600 km further North. This decision raises concerns about the technical and ethical aspects of the translocation. Firstly, there is a lack of proper evaluation and scientific evidence to support the need, opportunity, and feasibility of this translocation. The guanaco population is currently over one million and is increasing, and genetic differences exist among local populations. The translocation could produce anthropogenic‐driven admixed populations, leading to genetic swamping and disrupting evolutionary processes. Second, there are ethical conflicts around managing
wild species populations that prioritize private objectives and disregard local, publicly funded science. Rewilding projects require a deep understanding of interacting ecosystem processes, and of the socio‐economic context. This management decision violates guiding principles for rewilding and should have followed proper scientific evaluation and transparent local consultation.

Past and Recent Effects of Livestock Activity on the Genetic Diversity and Population Structure of Native Guanaco Populations of Arid Patagonia

Animals, 2021

Determining the impacts of human activities on natural populations is important for biodiversity ... more Determining the impacts of human activities on natural populations is important for biodiversity conservation. In this paper, we study the past and more recent effects of urbanization and livestock activity on the genetic diversity and population structure of endemic guanaco
populations of the arid Monte and Patagonian Steppe of central Argentina. Our results reveal that urbanization, the installation of fences, and the competition from sheep grazing coincided with the isolation of several guanaco populations, especially in areas with the highest intensity of livestock activity. However, our genetic analyses suggest that a more recent increase in connectivity among groups is occurring. Our results highlight the importance of implementing conservation management
plans for natural populations in arid and human-intervened environments.

POTENTIAL CONTRIBUTIONS OF MAMMALS TO HUMAN WELL-BEING IN ARGENTINA

by Ricardo Baldi and anahi formoso

Mastozoología Neotropical, 2022

Mammals are key components of biodiversity mediating ecosystem functions, mainly because of the d... more Mammals are key components of biodiversity mediating ecosystem functions, mainly because of the diversity of forms and functions of this group. Understanding and making explicit the role of mammals underpinning Nature’s Contributions to People (NCP) or directly contributing to human well-being would help to inuence policy formulation towards sustainable development and nature conservation. Through a workshop held at the XXXII Jornadas Argentinas de Mastozoología and subsequent collaborative work, we compiled information related to Mammal’s Contributions to People in Argentina (MCP-Arg) based on participants’ interpretation of the available literature and their eld experience. Argentinian mammals contribute to 12 of the 18 dened NCPs. We derived numerous MCP-Arg from studies that focused mainly on ecological processes and conservation, revealing an information gap in MCP-Arg description, quantication, and mapping. All taxa contribute similarly to the overall contributions, highlighting the importance of preserving mammal diversity. Conservation should also be framed at the local community rather than regional scales, aiming to preserve ecological functioning and contributions to human well-being, especially within regulation contributions. Our results show destructive feedback between threats and habitat-related contributions, with habitat degradation being the greatest threat to mammalian contributions and habitat maintenance the most threatened one. Our research indicates that a substantial amount of knowledge about MCP-Arg is available through narratives and interpretations. Considering the NCP approach to mammalian research, we can make signicant contributions to both mammal conservation and human well-being

The Status of the World’s Land and Marine Mammals: Diversity, Threat, and Knowledge

Science, 2008

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomical... more Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world’s mammals. Data, compiled by 1700+ experts, cover all 5487 species,
including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific
developments and conservation action.

Abundance Estimates of the Lesser Rhea Rhea pennata pennata in the Argentine Patagonia: Conservation Implications

Frontiers in Ecology and Evolution, 2015

Living on the edge: Heterogeneity in vegetation type cover as key factor of the habitat occupied by Dolichotis patagonum at landscape scale

Journal of Arid Envirinments, 2017

There is an urgent need to characterize the relationships between endangered species and their ha... more There is an urgent need to characterize the relationships between endangered species and their habitats in response to the accelerating pace of habitat transformation by humans. Mara (Dolichotis patagonum) is a large rodent endemic to the Argentine semi-deserts. It has been classified as "Near Threatened" by IUCN mainly as the result of habitat loss. There is contradictory evidence about the impact of human activities on mara and further information is needed to develop effective conservation strategies. We describe the main environmental factors, both natural and human, that are associated with warren presence as an indicator of the habitat selected by maras at the landscape scale. Habitat selected by maras was characterized by a high proportion of bare soil, low b diversity, open herbaceous steppe, and proximity to fences. The relationship of warren presence to the proportion of shrubby steppe in the broader landscape was variable across environments being positive in grasslands, and negative in shrubbier habitats. This supports the hypothesis that mara's preference for open areas depends on the level of shrubs in the surrounding habitat. As a result, conservation efforts will need to be tailored to the amount and structure of vegetation in any given area.

Breeding success of the endemic mara Dolichotis patagonum in relation to habitat selection: Conservation implications

Journal of Arid Environments, 2007

Although maras (Dolichotis patagonum) are among the most representative mammals of South America,... more Although maras (Dolichotis patagonum) are among the most representative mammals of South America, knowledge on the ecological processes affecting their conservation is scarce. In particular, the study of habitat requirements and its relationship with breeding success is necessary to identify possible threats and develop conservation action for this endemic mammal. I investigated habitat selection patterns by maras and their relationship with breeding success in Penı´nsula Valde´s, Argentine Patagonia. Maras bred from mid-August to late December, and they tended to build the breeding warrens in open, grass-dominated habitats more than expected while avoided closed habitats dominated by taller shrubs. Mean number of breeding adults per warren was 4.26, while mean number of pups born per warren was 4.46. Overall, 30 (45%) of 67 pups survived until the 6th week of life, but pups born in warrens located in open habitats survived significantly better than pups born in warrens located in closed habitats (50% vs. 30% of the pups born). As grass-dominated areas uphold the highest densities of domestic sheep and habitat modification due to overgrazing is a widespread process across arid Patagonia, effects on the availability of suitable breeding sites for maras are likely to occur and require further investigation. r

Analysis of the spatial variation in the abundance of lesser rheas using density surface models

by Ricardo Baldi and Romina D'Agostino

Wildlife Research, 2018

Context. The study of the spatial variation in abundance of wild populations and the identificati... more Context. The study of the spatial variation in abundance of wild populations and the identification of factors explaining the observed patterns are key both to understand aspects of basic ecology and the effects of human activities. This is usually difficult to evaluate for low-density and widely distributed species, such as the lesser rhea (Rhea pennata pennata), an endemic bird from South America. Recent advances in spatial modelling such as the density surface models (DSM) combine distance-sampling procedures with modelling techniques to produce maps of spatial variation in abundance, and its relationship with predictive variables.

Modeling the spatial structure of the endemic mara (Dolichotis patagonum) across modified landscapes

PeerJ, 2019

Across modified landscapes, anthropic factors can affect habitat selection by animals and consequ... more Across modified landscapes, anthropic factors can affect habitat selection by animals and consequently their abundance and distribution patterns. The study of the spatial structure of wild populations is crucial to gain knowledge on species' response to habitat quality, and a key for the design and implementation of conservation actions. This is particularly important for a low-density and widely distributed species such as the mara (Dolichotis patagonum), a large rodent endemic to Argentina across the Monte and Patagonian drylands where extensive sheep ranching predominates. We aimed to assess the spatial variation in the abundance of maras and to identify the natural and anthropic factors influencing the observed patterns in Península Valdés, a representative landscape of Patagonia. We conducted ground surveys during the austral autumn from 2015 to 2017. We built density surface models to account for the variation in mara abundance, and obtained a map of mara density at a resolution of four km 2 . We estimated an overall density of 0.93 maras.km -2 for the prediction area of 3,476 km 2 . The location of ranch buildings, indicators of human presence, had a strong positive effect on the abundance of maras, while the significant contribution of the geographic longitude suggested that mara density increases with higher rainfall. Although human presence favored mara abundance, presumably by providing protection against predators, it is likely that the association could bring negative consequences for maras and other species. The use of spatial models allowed us to provide the first estimate of mara abundance at a landscape scale and its spatial variation at a high resolution. Our approach can contribute to the assessment of mara population abundance and the factors shaping its spatial structure elsewhere across the species range, all crucial attributes to identify and prioritize conservation actions.

Choosing what is left. The spatial structure of a wild herbivore population within a livestock dominated landscape

PeerJ, 2020

Shrublands and grasslands comprise over 30% of the land surface and are among the most exploited ... more Shrublands and grasslands comprise over 30% of the land surface and are among the most exploited ecosystems for livestock production. Across natural landscapes, the distribution and abundance of wild herbivores are affected by interspecific competition for foraging resources, hunting and the development of infrastructure among other factors. In Argentine Patagonia, the abundance of domestic sheep grazing on native vegetation outnumbers the widely distributed guanaco (Lama guanicoe) and sheep ranching monopolizes the most productive lands. In this work, we aimed to assess the spatial variation in the abundance of guanacos in Península Valdés, a representative landscape of Patagonia, investigating the incidence of natural and human-related factors. We conducted ground surveys during the austral autumn in 2017 totaling 383.4 km along areas with and without sheep ranching. We built density surface models to account for the variation in guanaco abundance and obtained a map of guanaco density at a resolution of 4 km2. We estimated an overall density of 11.71 guanacos.km−2 for a prediction area of 3,196 km2, although the density of guanacos tripled in areas where sheep ranching was terminated
(in around 20% of the surface of Península Valdés) compared to areas with
sheep. Guanacos were more abundant at lower values of primary productivity
and sheep stocking rates and further from inhabited ranch buildings, suggesting competition with sheep and conflict with humans. Although guanacos selected open, grass-dominated habitats across sheep-free sites, fences dividing properties and paddocks played a significant role in the spatial structure of their population in Península Valdés affecting negatively the abundance of guanacos. Our results indicate that actions to improve habitat connectivity for guanacos, favor the coexistence among guanacos and sheep ranching, and promote responsible
human activities and attitudes towards wildlife are needed.

The impact of conservation on the status of the world's vertebrates

Science (New York, N.Y.), Jan 10, 2010

Ecological drivers of guanaco recruitment: variable carrying capacity and density dependence

Oecologia, 2014

fluctuates in response to climatic variation, and that these fluctuations have relevant consequen... more fluctuates in response to climatic variation, and that these fluctuations have relevant consequences for herbivore dynamics, such as amplifying density dependence in drier years. We conclude that including the coupling between environmental variability in resources and density dependence is crucial to model ungulate population dynamics; to overlook temporal changes in carrying capacity may even mask density dependence as well as other important processes.

Ecological Correlates of Group-Size Variation in a Resource-Defense Ungulate, the Sedentary Guanaco

PLoS ONE, 2014

For large herbivores, predation-risk, habitat structure and population density are often reported... more For large herbivores, predation-risk, habitat structure and population density are often reported as major determinants of group size variation within and between species. However, whether the underlying causes of these relationships imply an ecological adaptation or are the result of a purely mechanistic process in which fusion and fragmentation events only depend on the rate of group meeting, is still under debate. The aim of this study was to model guanaco family and bachelor group sizes in contrasting ecological settings in order to test hypotheses regarding the adaptive significance of group-size variation. We surveyed guanaco group sizes within three wildlife reserves located in eastern Patagonia where guanacos occupy a mosaic of grasslands and shrublands. Two of these reserves have been free from predators for decades while in the third, pumas often prey on guanacos. All locations have experienced important changes in guanaco abundance throughout the study offering the opportunity to test for density effects. We found that bachelor group size increased with increasing density, as expected by the mechanistic approach, but was independent of habitat structure or predation risk. In contrast, the smaller and territorial family groups were larger in the predator-exposed than in the predator-free locations, and were larger in open grasslands than in shrublands. However, the influence of population density on these social units was very weak. Therefore, family group data supported the adaptive significance of group-size variation but did not support the mechanistic idea. Yet, the magnitude of the effects was small and between-population variation in family group size after controlling for habitat and predation was negligible, suggesting that plasticity of these social units is considerably low. Our results showed that different social units might respond differentially to local ecological conditions, supporting two contrasting hypotheses in a single species, and highlight the importance of taking into account the proximate interests and constraints to which group members may be exposed to when deriving predictions about group-size variation.

Response of guanacos Lama guanicoe to changes in land management in Península Valdés, Argentine Patagonia: conservation implications

Oryx, 2012

Response of guanacos Lama guanicoe to changes in land management in Península Valdé s, Argentine ... more Response of guanacos Lama guanicoe to changes in land management in Península Valdé s, Argentine Patagonia: conservation implications M a r í a V i r g i n i a B u r g i , A n d r e a M a r i n o , M a r í a V i c t o r i a R o d r í g u e z G u s t a v o P a z o s and R i c a r d o B a l d i Abstract The guanaco Lama guanicoe was the only large native herbivore widely distributed across Patagonia until the introduction of domestic sheep Ovis aries. Guanacos have declined because of competition with sheep for forage, high hunting pressure and habitat degradation. Península Valdés is a protected area where sheep ranching is the predominant activity. A ranch formerly dedicated to sheep production was converted into a private wildlife reserve, from which all the sheep were removed in 2005. We studied changes in guanaco abundance inside and outside the reserve after sheep removal, and also plant cover of various vegetation types. We found that guanaco abundance was higher inside than outside the reserve, and increased by three-fold within 3 years. Total plant cover and grass cover were higher inside than outside the reserve. Our results showed that guanacos reacted rapidly to changes in management, and suggest that even at a high density guanacos would not be as damaging to the vegetation as sheep. Although management changes resulted in significant changes in guanaco abundance locally, the size of a protected area influences the persistence of wild populations. A large herbivore such as the guanaco needs to be managed across large areas. We believe it is necessary to implement a management plan for Península Valdés that allows for the coexistence of sustainable livestock production and healthy wildlife populations.

Sex-related spatial patterns of Poa ligularis in relation to shrub patch occurrence in northern Patagonia

Journal of Vegetation Science, 2000

Poa ligularis is a dioecious species and a valuable forage plant which is widespread in the arid ... more Poa ligularis is a dioecious species and a valuable forage plant which is widespread in the arid steppe of northern Patagonia (Argentina). The vegetation in these areas consists of a system of perennial plant patches alternating with bare soil areas defining contrasting micro-environments. We hypothesized that (1) male and female individuals of P. ligularis are spatially segregated in different micro-environments, (2) the intensity of spatial segregation of sexes depends on plant structure and (3) spatial segregation of sexes is enhanced by competitive interactions between the sexes within the vegetation patches. We analysed the spatial distribution of female and male individuals in relation to the spatial pattern of vegetation in two areas differing in their vegetation structure. The location of P. ligularis within patches where either male, female or both sexes occurred was also analysed. The results indicate that different patterns of spatial distribution of sexes of P. ligularis may be found at the community level depending on the dominant life forms and geometric structure of plant patches. Where patches are of a lower height, with a high internal patch cover, individuals of both sexes are concentrated within patch canopies. In sites characterized by large, tall patches and less internal patch cover suitable microsites for female and male P. ligularis occur both within and outside the patch with males located at further distances from the patch edge. Where the patch is large and tall enough to allow the establishment of males and females at relatively high numbers, males occupy the patch periphery or even colonize the interpatch bare soil. These spatial patterns are consistent with selective traits in which females better tolerate intraspecific competition than males, while males tolerate wider fluctuations in the physical environment (soil moisture, nitrogen availability, wind intensity, etc.).

ABUNDANCIA Y DISTRIBUCIÓN DEL GUANACO (Lama guanicoe), EN EL NE DEL CHUBUT, PATAGONIA ARGENTINA

3 Fundación Patagonia Natural. Marcos A. Zar 760, (9120) Puerto Madryn, Chubut. TEL/FAX: (0965) 7... more

Social effects of space availability on the breeding behaviour of elephant seals in Patagonia

Animal Behaviour, 1996

The Patagonian breeding colony of southern elephant seals,Mirounga leonina, of Penı́nsula Valdés,... more The Patagonian breeding colony of southern elephant seals,Mirounga leonina, of Penı́nsula Valdés, Argentina is characterized by long, continuous, homogeneous and spacious beaches. Reproduction in this colony occurs at the lowest group densities reported for the species. The availability of ample space resulted in the dispersion of reproductive females along 160 km of coastline, with a range of 0–300 reproductive individuals per km. Females grouped together in small harems (median=11 females, range 2–122,N=432), and individual distance between females was one to two female body lengths. Body contact within the harem was rare. Consequently, agonistic interactions (AIs) between females and female aggression (Ag) towards alien pups occurred infrequently (median rate=4 AIs/female per 100 h and 1 Ag/pup per 100 h, respectively). Pup mortality rate was low for an elephant seal rookery (3.5% for 3487 pups). Most dead pups were stillborn, and only three of 38 pups whose cause of mortality could be determined died from trauma or starvation following mother–pup separation. Female dispersal allowed many males to have access to females. About 45% of all males of reproductive size in the colony (about 1000 individuals) had a harem. Most adult males mated with receptive females. Low-density breeding conditions benefited female reproductive success through an increase in pup survival. Female dispersal resulted in small harem size, however, and limited the potential for polygyny. 1996 The Association for the Study of Animal Behaviour

BREEDING BIOLOGY OF SOUTHERN ELEPHANT SEALS IN PATAGONIA

Marine Mammal Science, 1993

Abstract: Elephant seals breed in Patagonia (Península Valdés, Argentina) from late August to ear... more Abstract: Elephant seals breed in Patagonia (Península Valdés, Argentina) from late August to early November, reaching peak numbers during the first week in October. Observations of this population over the past ten years yielded similar results. Eighty percent of the pups were born by 2 October. Most (96%) of 663 females marked during three breeding seasons gave birth to a pup. Females stayed on land a mean of 28 d, gave birth 6 d after arrival, nursed their pups for 22 d, and copulated a mean of 2.5 times 20 d after parturition and 2 d before departure. Copulations peaked during the third week in October. Males spent 57–80 d on land fasting and defending harems of up to 134 females (median 11–13 females, depending on year). Most (96%) marked females that gave birth (n= 636) also weaned their pups successfully. Pup sex ratio was unity. Harems were smaller and breeding occurred about three weeks earlier in Patagonia than in other colonies. Thermal conditions, day length and food availability may explain clines in the timing of breeding events between populations, Other parameters of the breeding season for the expanding Patagonia colony are similar to those for declining southern elephant seal populations elsewhere.

Guanacos and sheep: evidence for continuing competition in arid Patagonia

Oecologia, 2001

Guanacos (Lama guanicoe) are the only wild ungulate species widely distributed across the Patagon... more Guanacos (Lama guanicoe) are the only wild ungulate species widely distributed across the Patagonian steppe and have undergone a precipitous population decline since the introduction of domestic sheep (Ovis aries) 100 years ago. There has been speculation that sheep ranching may have played a major role in guanaco population decline after monopolising the most productive land because of competition for forage plants. Our aim in this work was to estimate guanaco abundance and account for its variation across nine different sites, two seasons and two years. We conducted over 100 ground surveys of both guanacos and sheep and estimated the availability of the preferred plant species both animal species might select in their diet. We found that (1) sheep densities were up to 23 times higher than guanaco densities in sympatric conditions, (2) at a protected site without sheep, guanaco density was one order of magnitude higher than at the rest of the sites, (3) across nine different sites, sheep densities alone accounted for around 60% of the variation in guanaco abundance, (4) guanaco densities were negatively related to both total plant cover and availability of the preferred plant species in their diet, which were both positively associated with sheep density, and (5) within-site changes in guanaco densities between seasons and years were negatively related to changes in sheep densities. Our results are consistent with predictions on interspecific competition for food resources, although we cannot rule out possible effects of other human-related activities influencing guanaco abundance. We conclude that sheep compete with guanacos for forage in arid Patagonia.

HIGH POTENTIAL FOR COMPETITION BETWEEN GUANACOS AND SHEEP IN PATAGONIA

Journal of Wildlife Management, 2004

Guanacos (Lama guanicoe) are the largest native Artiodactyl in South America, and the most widely... more Guanacos (Lama guanicoe) are the largest native Artiodactyl in South America, and the most widely distributed. In arid Patagonia, densities are low and negatively related to domestic sheep numbers in space and time consistent with interspecific competition theory. Although guanacos and domestic sheep have been described as intermediate feeders sharing food resources, no studies have been conducted to compare their diets in sympatric conditions and explore whether the potential exists for direct interspecific competition. We assessed the diet of both species across 9 different sites and 2 seasons by microhistological analysis of fecal samples. We found that (1) guanacos and sheep are generalist herbivores feeding on a wide range of plant species; (2) both are intermediate feeders able to include both monocotyledoneous and dicotyledoneous plants in their diet; (3) both are able to change their diets seasonally; and (4) food niche overlap is high, particularly in summer when food resources are more scarce than in spring. We conclude that the potential for competition between guanacos and sheep is high and could have played a major role in the demise of guanacos. Consequently, current management practices focused on maximizing sheep numbers are not compatible with the recovery of guanaco populations.

Animal Diversity, Distribution and Conservation

P. Bouza and A. Bilmes (eds.), Late Cenozoic of Península Valdés, Patagonia, Argentina, 2017

In this chapter, we summarize the ecological information available on the species of arthropods, ... more In this chapter, we summarize the ecological information available on the species of arthropods, reptiles, terrestrial birds and mammals known to occur at Península Valdés, within the context of the Monte and Patagonia eco-regions. Two hundred species of insects and spiders, 12 species of reptiles, 139 species of birds and 23 species of native mammals inhabit today the island-like peninsula. We describe the community structure, distribution and abundance of the different taxa according to current knowledge. As the Península Valdés region is a World Natural Heritage Site and a provincial protected area of high importance for the conservation of biodiversity and the regional economy, we found relevant to summarize knowledge on the effects of human activities on different components of biodiversity. Habitat degradation, grazing by domestic sheep and poaching are major 263 threats to wildlife, although Península Valdés still harbours some of the most abundant populations of wild species in Patagonia. It is a priority to implement the management plan available for Península Valdés, taking into account the interactions between biodiversity, the different human activities and the physical environment. At the same time, it is necessary to identify and implement actions to conserve wild species and habitats, and also to develop programmes for the coexistence of responsible human activities and healthy wildlife populations.