Ramiro Daniel CregoSmithsonian Institution · Smithsonian Conservation Biology Institute
Ramiro Daniel Crego
PhD
I am currently a postdoctoral researcher, looking for opportunities to continue developing my academic career.
About
44
Publications
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Introduction
I am Ramiro D. Crego, an ecologist from Argentina. My research interests are in the field of ecology and conservation biology. I am interested in the most fundamental state variables in ecology, distribution and abundance of species, and how these state variables respond to rapid global changes. These include, invasive species, climate change and different human activities, such as, livestock production. My work has had an emphasis on birds and mammals inhabiting semi-arid grasslands of Argentina and Kenya, and temperate forests in southern Chile. In my studies I use a combination of field data collection, remote sensing and advance modeling techniques. Results from different studies have a main focus on creating information that can help managers to make science-based decisions.
Additional affiliations
July 2018 - present
January 2015 - January 2015
June 2013 - December 2017
Education
May 2010 - December 2012
February 2002 - December 2008
Publications
Publications (44)
With ecosystems increasingly having co-occurring invasive species, it is becoming more important to understand invasive species interactions. At the southern end of the Americas, American beavers (Castor canadensis), muskrats (Ondatra zibethicus), and American mink (Neovison vison), were independently introduced. We used generalized linear models t...
Private lands are critical for maintaining biodiversity beyond protected areas. Across Kenyan rangelands, wild herbivores frequently coexist with people and their livestock. Human population and livestock numbers are projected to increase dramatically over the coming decades. Therefore, a better understanding of wildlife-livestock interactions and...
Aim
Google Earth Engine (GEE) is a free Web‐based spatial analysis platform that requires only a web browser and an Internet connection to programmatically access and analyse data from its multi‐petabyte catalog of regularly updated satellite imagery (e.g. MODIS, Landsat, Sentinel) and other geospatial datasets. The high computing capacity of GEE c...
![Trends in (a) annual mean vicuña densities [95% CI] from distance...](publication/358679988/figure/fig1/AS:1148725569290240@1650888926370/Trends-in-a-annual-mean-vicuna-densities-95-CI-from-distance-sampling-transects_Q320.jpg)
Disease outbreaks induced by humans increasingly threaten wildlife communities worldwide. Like predators, pathogens can be key top‐down forces in ecosystems, initiating trophic cascades that may alter food webs. An outbreak of mange in a remote Andean protected area caused a dramatic population decline in a mammalian herbivore (the vicuña), creatin...
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...
Over a quarter of the world's land surface is grazed by cattle and other livestock, which are replacing wild herbivores and widely regarded as drivers of global biodiversity declines. The effects of livestock presence versus absence on wild herbivores are well documented. However, the environmental context-specific effects of cattle stocking rate o...
Understanding how wildlife interacts with human activities across non-protected areas are critical for conservation. This is especially true for ungulates that inhabit human-dominated landscapes outside the protected area system in Nepal, where wildlife often coexists with livestock. Here we investigated how elevation, agricultural land, distance f...
La Reserva de Biosfera Cabo de Hornos (RBCH) alberga una biodiversidad y tipos
de ecosistemas únicos a nivel mundial. Éstos han sido mucho menos estudiados que
sus homólogos, los ecosistemas subpolares del hemisferio norte. El objetivo de este
trabajo es presentar por primera vez una detallada descripción de los marcados
gradientes climáticos de la...
Movement ecologists have witnessed a rapid increase in the amount of animal position data collected over the past few decades, as well as a concomitant increase in the availability of ecologically relevant remotely sensed data. Many researchers, however, lack the computing resources necessary to incorporate the vast spatiotemporal aspects of datase...
The extinction of 80% of megaherbivore (>1,000 kg) species towards the end of the Pleistocene altered vegetation structure, fire dynamics, and nutrient cycling worldwide. Ecologists have proposed (re)introducing megaherbivores or their ecological analogues to restore lost ecosystem functions and reinforce extant but declining megaherbivore populati...
ContextReduced connectivity across grassland ecosystems can impair their functional heterogeneity and negatively impact large herbivore populations. Maintaining landscape connectivity across human-dominated rangelands is therefore a key conservation priority.Objective
Integrate data on large herbivore occurrence and species richness with analyses o...
Las reservas de la biosfera tienen entre sus funciones apoyar la investigación científica, educación, capacitación y monitoreo. En la Reserva de la Biosfera Cabo de Hornos (RBCH), creada el año 2005, estas funciones se han cumplido desde la conformación del Parque Etnobotánico Omora el año 2000 y con su implementación, el año 2008, como sitio co-fu...
Nest predation by invasive mammalian predators can cause major impacts on native bird populations. The American Mink (Neovison vison) was recently introduced in Navarino Island, southern Chile, where it established itself as a new terrestrial mesopredator on the island, with documented impacts on waterfowls' breeding success. However, little is kno...
Biocultural conservation increasingly requires transdisciplinary collaborations, which includes different disciplines, institutions and actors. The collaboration between scientists and the Chilean Navy has been an effective way to address this requirement. This inter-institutional collaboration between the Navy and the Sub-Antarctic Biocultural Con...
Background
Birds can maximize their reproductive success through careful selection of nest-sites. The ‘total-foliage’ hypothesis predicts that nests concealed in vegetation should have higher survival. We propose an additional hypothesis, the ‘predator proximity’ hypothesis, which states that nests placed farther from predators would have higher su...
The southernmost archipelago of the Americas is dominated by invasive mammals that outnumber their native counterparts. Despite the relatively low ability of most invasive mammals to cross cold sea water channels, invaders are apparently colonizing new islands. Our objective was to provide an assessment of the expansion of invasive mammals within t...
Abstract
Background: There is limited knowledge about the breeding strategies of birds inhabiting in South American temperate forests. This is particularly true for open-cup forest passerines breeding at high latitudes (> 42°). To better understand the ecology of these species, in this study we described and compared the breeding strategies
(i.e.,...
Over one-quarter of the Earth’s land surface is used as rangeland for grazing domestic livestock. Rangelands are the dominantland use in Laikipia County, Kenya, which is also a global biodiversity hotspot for birds and large mammals. Our objective was to disentangle
the influences of climatic and anthropogenic drivers on vegetation trends in Laikip...
Species with wide breeding ranges have evolved different breeding strategies at different latitudes. Most
passerines breeding in the South American temperate forest biome (30-55 S) have wide breeding ranges;
however, most studies have been conducted in its northern region (30-42°S). Here for the first time, and
during three breeding seasons (201...
El Antropoceno está marcado por un pervasivo proceso de homogeneización biocultural que conlleva pérdidas de biodiversidad y de culturas. Dicha homogeneización se evidencia en el caso de algunas invasiones biológicas. La ética biocultural procura contrarrestar tal homogeneización. Para este fin se ha diseñado una aproximación metodología denominada...
The success of an invasive species depends in part on its niche and the new niche opportunities that such species may find in the invaded habitat. Niche opportunities can be understood as the potential provided by a community to an invasive species to expand its niche by changes in habitat use, behavior, or diet, that favors population growth, refl...
Invasive predators are responsible for the extinction of numerous island species worldwide. The naïve prey hypothesis suggests that the lack of co-evolutionary history between native prey and introduced predators results in the absence of behavioral responses to avoid predation. The lack of terrestrial mammal predators is a core feature of islands...
At the southern end of the Americas exist one of the last pristine ecosystems in the world, the sub-Antarctic Magellanic forests ecoregion, protected by the Cape Horn Biosphere Reserve (CHBR). Despite its remote location, the CHBR has been subject to the growing influences of globalization, a process that has driven cultural, biotic, and economic t...
In this study, we explored “niche expansion” in the invasive American mink population that established on Navarino Island, southern Chile, in the late 1990s by using multi-season occupancy models.
Se reporta la presencia de dos especies de Vespula para la Reserva de Biosfera Cabo de Hornos. Las características taxonómicas para su identificación y los registros geográficos de ambas especies en la RBCH. Se analizan y sugieren estrategias de control y un programa de educación ambiental. Además se menciona el primer registro de Bombus terrestris...
La avispa común Vespula vulgaris (Linnaeus 1758) es una especie introducida en el Hemisferio Sur que ha sido registrada en Australia, Nueva Zelanda, Tasmania, Argentina y Chile central. Este trabajo documenta la presencia de V. vulgaris en la isla Navarino, Reserva de la Biósfera Cabo de Hornos, sur de Chile.
Background/Question/Methods
Invasive species are a major driver of biodiversity loss, even in remote regions of the world. Negative impacts on invaded ecosystems can be more severe when two or more invasive species act synergistically (invasional meltdown). At the southern end of the Americas, three species that naturally interact in their native r...
La Reserva de la Biosfera Cabo de Hornos (RBCH) se ubica en el extremo sur del continente sudamericano. Dado el gran remanente de vegetacion nativa, junto a la baja fragmentacion y baja densidad-poblacional humana, la region se encuentra catalogada como una de las ultimas 24 areas pristinas del planeta (Mittermeier et al. 2003). La RBCH esta embebi...
The American mink (Neovison vison) has been described as one of the worst invasive species in the northern hemisphere. Although some studies on the mink exist for the southern hemisphere, aside from impacts on marine and freshwater birds, its effect on other components of the biota is not well understood. Here, as a result of 3 different studies, w...
The long-term socio-ecological research (LTSER) study sites should integrate theoretical and applied research to effectively confront global socio-environmental change. For a socio-ecological integration beyond the socio-economic approach that prevails today in LTSER networks worldwide, in the southernmost site of the LTSER-Chile network (Omora Par...
Background/Question/Methods
Invasive species are a significant component of global change, affecting native species, communities and ecosystems around the world. Among the most vulnerable are islands, where the introduction and establishment of mammalian predators are considered a major threat to native species. Here we report on a study conducte...
Climate change is predicted to be a major threat for biodiversity and, from a conservation prospective, it is important to understand how ecosystems may respond to that change. Predicted climate change effects on the distribution of meadows in the arid and semi-arid Argentinean Patagonia by 2050 were assessed for change trends and areas of desertif...
We used and evaluated the effectiveness of a hand-capture technique to capture and mark neonatal vicuñas (Vicugna vicugna) at San Guillermo National Park, west-central Argentina. We captured and marked 98 neonates during 5–31 January, 2008–2010. Capture success was 92% (106 attempts), with stationary marking teams being 2.5 times as successful in d...
RESUMEN.— En este trabajo se propone una técnica para estimar la densidad del Inambú Común (Nothura maculosa) y evaluar cuantitativamente sus tendencias poblacionales en ambientes de pastizal. Se estimó la densidad del Inambú Común en la sierras de Tandil, provincia de Buenos Aires, mediante dos técnicas: transectas de ancho variable y transectas d...
Questions
Questions (5)
Hi all
It is the second time my C drive is deleted completely when running Linkage Mapper Tool for connectivity analysis on GIS. Apparently it happened when setting the project directory directly to the C drive.
Did anybody else encounter this crazy problem? At least this time I was prepared and had a back up. The annoying thing is that is also deleted all my drop box folders!
I am just wandering if this is a common issue and if not just to warn you all about it.
Ramiro
I am looking specifically into a GAMM model now, but I think this is relevant for all families of mixed-effect models.
Hi,
I have been trying to find an answer to this question without success. Maybe, some one can help me.
I have been fitting dynamic occupancy models. I tested the most complex model with a Goodness-of-fit test as recommended by (MacKenzie & Bailey 2004; MacKenzie et al. 2006) and obtained no evidence of lack of fit (p>0.05) and c-hat= 1.17. I know c-hat should be 1 and if it is >1 data is probably over dispersed. However, how much higher than 1 is evidence of over dispersion? I have not seen a single model (GLMs) with a c-hat value of just 1, and I am wondering whether or not I should conduct model selection with QAIC, as my c-hat value is pretty close to 1.
I will appreciate very much a response.
Ramiro
Hi. I have count data from camera traps and want to assess if there is a relationship between capture rate and a covariable. When i standardize counts per number of trap nights, the variable gets continuous. Is it okay to run GLM with Poisson or negative binomial dist even my count data is now continuous? If not, is there a way around this problem?
Hi,
Working on model selection using AIC criterion, I just found this interesting paper from Arnold (2009), recommending to use 85% CI instead of the common used 95% CI when reporting model parameter estimates.
Arnold, T.W. (2009) Uninformative Parameters and Model Selection Using Akaike’s Information Criterion. Journal of Wildlife Management, 74, 1175–1178. (attached)
I am surprised that even it is a good argument and published several years ago, I have seen so far only one paper reporting CI at 85%. It could be that I do not read much, even I think I do, or that I missed something that could be wrong in Arnold's argument.
I wonder if someone with more experience could give me a thought about it, and if I should report 85% CI or 95% CI and interpret results accordingly,
Many thanks,
Ramiro
Projects
Project (1)
