Ecological Niche Modeling Research Papers (original) (raw)
Understanding the origin and maintenance of phenotypic variation, particularly across a continuous spatial distribution, represents a key challenge in evolutionary biology. For this, animal venoms represent ideal study systems: they are... more
Understanding the origin and maintenance of phenotypic variation, particularly across a continuous spatial distribution, represents a key challenge in evolutionary biology. For this, animal venoms represent ideal study systems: they are complex, variable, yet easily quantifiable molecular phenotypes with a clear function. Rattlesnakes display tremendous variation in their venom composition, mostly through strongly dichotomous venom strategies, which may even coexist within a single species. Here, through dense, widespread population-level sampling of the Mojave rattlesnake, Crotalus scutulatus, we show that genomic structural variation at multiple loci underlies extreme geographical variation in venom composition, which is maintained despite extensive gene flow. Unexpectedly, neither diet composition nor neutral population structure explain venom variation. Instead, venom divergence is strongly correlated with environmental conditions. Individual toxin genes correlate with distinct environmental factors, suggesting that different selective pressures can act on individual loci independently of their co-expression patterns or genomic proximity. Our results challenge common assumptions about diet composition as the key selective driver of snake venom evolution and emphasize how the interplay between genomic architecture and local scale spatial heterogeneity in selective pressures may facilitate the retention of adaptive functional polymorphisms across a continuous space.
- by and +3
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- Evolutionary Biology, Genetics, Genomics, Transcriptomics
Mine associated wastewater is characteristically elevated in metals and other contaminants and has been conventionally treated with costly chemical applications. The development of passive treatment systems such as wetlands, which employ... more
Mine associated wastewater is characteristically elevated in metals and other contaminants and has been conventionally treated with costly chemical applications. The development of passive treatment systems such as wetlands, which employ both biotic and abiotic processes, has been recognized as an economically feasible, ecologically acceptable treatment technology in the last decade. Not only can constructed wetlands provide an efficient facility
The Perote ground squirrel ( Xerospermophilus perotensis ) is an endangered microendemic species, restricted to a closed basin between the Mexican states of Puebla, Tlaxcala, and Veracruz. Information on its natural history is still... more
The Perote ground squirrel ( Xerospermophilus
perotensis ) is an endangered microendemic species,
restricted to a closed basin between the Mexican states of
Puebla, Tlaxcala, and Veracruz. Information on its natural
history is still limited, and there are no previous predation
records for this species. Herein, we report a predation
event on a Perote ground squirrel by a prairie falcon
( Falco mexicanus ) and discuss how we determined the
taxonomic identity of the recovered prey remains.
Prehistoric water management in the northern US Southwest was integral to successful subsistence. On the Mesa Verde cuesta in southwestern Colorado, several types of water management features have been identified in the archaeological... more
Prehistoric water management in the northern US Southwest was integral to successful subsistence. On the Mesa Verde cuesta in southwestern Colorado, several types of water management features have been identified in the archaeological record, but research into these features has typically focused on the efficacy of reservoirs—a large-scale, labor-intensive, and community-oriented means of collecting and storing water. This focus on large-scale water management features has largely ignored the productive potential of small-scale and low-cost strategies for water management executed by individual households. There is considerable evidence, for example, that extensive check dam networks were constructed and used on the Mesa Verde cuesta, but their actual utility as a small-scale risk-aversion strategy to resource stress has not systematically been explored. This paper identifies all ephemeral drainages on the Mesa Verde cuesta where check dam construction was possible, then applies a maize growing niche model to estimate total yields from check dam farming plots for each year from AD 890–1285. A demographic reconstruction is then used to estimate the percentage of the total cuesta population that could have been supported using only check dam maize yields through time. Results suggest that check dam farming could have supplied a reliable source of surplus annual maize sufficient for household storage needs even during the most populous time periods across the cuesta landscape.
Nursamsi I, Partasasmita R, Cundaningsih N, Ramadhani HS. 2018. Modeling the predicted suitable habitat distribution of Javan hawk-eagle Nisaetus bartelsi in the Java Island, Indonesia. Biodiversitas 19: 1539-1551. Javan hawk-eagle... more
Nursamsi I, Partasasmita R, Cundaningsih N, Ramadhani HS. 2018. Modeling the predicted suitable habitat distribution of Javan hawk-eagle Nisaetus bartelsi in the Java Island, Indonesia. Biodiversitas 19: 1539-1551. Javan hawk-eagle (Nisaetus bartelsi) is an endemic raptor of Java Island. The conservation status of Javan hawk-eagle (JHE) according to IUCN is endangered (EN) and included in CITES Appendix II list, and this species is also protected by the Indonesian government law based on act no. 5, year 1990. The position of Javan hawk-eagle as a top predator is now very threatened by habitat fragmentation, wildlife trade, and the declining quality of its habitat. The primary purpose of this study was to give preliminary information about the distribution of predicted suitable habitat for JHE as a means of finding potential releasing sites, as an evaluation for habitat protection, and even as an option for the development of new JHE protected areas. However, mapping the spatial distribution of potential habitat for JHE using terrestrial survey is problematic because it requires enormous time, fund, and human resources. The most possible approach is by using Ecological Niche Modeling (ENM)/species distribution modeling (SDM). In this study, modeling exercise was conducted by using a maximum entropy method as an adaptation from Maxent software ver. 3.4.1, with the utilization of JHE-nest coordinate data and 16 environmental variables datasets as the main input. The predicted suitable habitat distribution map has shown a good match with historical and present records of JHE and has fairly succeeded in capturing a wide range of habitat patches from tiny spots to quite large suitable habitat. Modeling results also showed that altitude, annual mean temperature, and two types of land cover (closed shrub, and forest area) are considered to be most important variables affecting the distribution of potential habitat for JHE. Moreover, about 17.77% (23,209 km 2) area of Java Island has been projected to be suitable for Havan Hawk-Eagle's habitat, which mostly spread in mountainous areas while also appear in several lowland areas. This study suggests the importance of topographic, climatic, and land cover as pivotal predictors in determining the suitability of habitat for JHE. This study also shows that the modeling results have a good match with the historical records of JHE across the island, which suggests the overall accuracy of the model.
Aquatic invasive species are a major threat to native freshwater ecosystems and cause enormous ecological and economic damage worldwide. Didymosphenia geminata (Lyngbye) M. Schmidt is an emerging invasive aquatic species that is spreading... more
Aquatic invasive species are a major threat to native freshwater ecosystems and cause enormous ecological and economic damage worldwide.
Didymosphenia geminata (Lyngbye) M. Schmidt is an emerging invasive aquatic species that is spreading aggressively in Southern South America.
Using niche analysis and species distribution models (SDMs), we examined niche requirements of D. geminata using climatic, topographic, and
biological variables. We compared the realized niche of the species in the United States (US) with the niche in Chile. Within Chile, we also
examined the environmental conditions (environmental envelopes) of rivers with and without this alga, to assess whether this species has the
potential to colonize more rivers. Finally, we compared the SDMs from the US and Chile projected to Chile. Results showed that the potential
distribution of D. geminata varied significantly between US and Chile. The US-based model predicted a geographic distribution in Chile which
ranged from 32º to 55º S latitude while the Chile-based model predicted suitable habitats only from 36° to 48º S, and not so in the coastal ranges nor
in Southern Patagonia ( ̴ 52–55°S). In Chile, we found no differences in the environmental envelopes of the invaded and uninvaded rivers, thus
suggesting that this species has even more suitable habitats to invade. These results can be used for prioritizing survey sites in Southern Chile for an
early detection and management of D. geminata and for the conservation of native flora and fauna in freshwater ecosystems in Chile.
In the last two decades, interest in species distribution models (SDMs) of plants and animals has grown dramatically. Recent advances in SDMs allow us to potentially forecast anthropogenic effects on patterns of biodiversity at different... more
In the last two decades, interest in species distribution models (SDMs) of plants and animals has grown dramatically. Recent advances in SDMs allow us to potentially forecast anthropogenic effects on patterns of biodiversity at different spatial scales. However, some limitations still preclude the use of SDMs in many theoretical and practical applications. Here, we provide an overview of recent advances in this field, discuss the ecological principles and assumptions underpinning SDMs, and highlight critical limitations and decisions inherent in the construction and evaluation of SDMs. Particular emphasis is given to the use of SDMs for the assessment of climate change impacts and conservation management issues. We suggest new avenues for incorporating species migration, population dynamics, biotic interactions and community ecology into SDMs at multiple spatial scales. Addressing all these issues requires a better integration of SDMs with ecological theory.
Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta (Gaertn. f.) forests in Nepal. We also related varieties of diversity... more
Diversity and regeneration of woody species were investigated in two ecological niches viz. gap and intact vegetation in old-growth seasonally dry Shorea robusta (Gaertn. f.) forests in Nepal. We also related varieties of diversity measures and regeneration attributes to gap characteristics. Stem density of tree and shrub components is higher in the gap than in the intact vegetation. Seedling densities of S. robusta and Terminalia alata (B. Heyne ex Roth.) are higher in the gap than in the intact vegetation, while contrary result is observed for T. bellirica (Gaertn. ex Roxb.) and Syzigium cumini (L. Skeels) in term of seedling density. The complement of Simpson index, Evenness index, and species-individual ratio in the seedling layer are lower in the gap than the intact vegetation. Gap size can explain species richness and species establishment rate. Gaps created by multiple tree falls in different years have higher seedling density of S. robusta than gaps created by single and/or multiple tree falls in the same year. In conclusion, gaps maintain species diversity by increasing seedling density, and favor regeneration of Sal forests. In addition to gap size, other gap attributes also affect species diversity and regeneration.
Ecological Niche Modelling (ENM) is widely used to depict species potential occurrence according to environmental variables under different climatic scenarios. We tested the ENM approach to infer past range dynamics of cork oak, a... more
Ecological Niche Modelling (ENM) is widely used to depict species potential occurrence according to environmental variables under different climatic scenarios. We tested the ENM approach to infer past range dynamics of cork oak, a keystone species of the Mediterranean Biome, from 130 ka to the present time. Hindcasting implications would deal with a better species risk assessment and conservation management for the future. We modelled present and past occurrence of cork oak using seven ENM algorithms, starting from 63,733 spatially unique presence points at 30 arc-second resolution. Fourteen environmental variables were used and four time slices were considered (Last Interglacial, Last Glacial Maximum, mid-Holocene and present time). A threshold-independent evaluation of the goodness-of-fit of the models was evaluated by means of ROC curve and fossil or historical evidences were used to validate the results.
Four weighted average maps depicted the dynamics of area suitability for cork oak in the last 130 ka.
The derived species autoecology allowed its long-term occurrence in the Mediterranean without striking range reduction or shifting. Fossil and historical post-processing validation support the modelled past spatial extension and a neglected species presence at Levantine until the recent time.
Despite the severe climatic oscillation since the Last Glacial Maximum, cork oak potential distribution area experienced limited range changes, confirming its strong link with the Mediterranean Basin. The ecological amplitude of Quercus suber could be therefore adopted as a reference to trace the Mediterranean bioclimate area. A better knowledge of the past events of Mediterranean vegetation, a wider range of study species and environmental determinants are essential to inform us about its current state, its sensitivity to human impact and the potential responses to future changes.
- by Soumia FAHD and +1
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- Earth Sciences, Conservation, West Africa, Arid environments
Geophagy is well known among some Neotropical parrots. The clay apparently adsorbs dietary toxins and/or provides supplemental nutrients. We used location data and 23 environmental layers to develop a predictive model of claylick... more
Geophagy is well known among some Neotropical parrots. The clay apparently adsorbs dietary toxins and/or provides
supplemental nutrients. We used location data and 23 environmental layers to develop a predictive model of claylick
distribution using Maxent software. We related species characteristics to claylick use and examined how parrot
assemblages using claylicks changed with distance from the centre of claylick distribution. Fifty-two parrot claylicks
were reported from an area of ca 4 million km2 but over 50% were restricted to a 35 000 km2 region of southeast
Peru and northern Bolivia. Claylicks were strongly associated with moist forest on younger (B65 millions of yr)
geological formations and exposed river banks. The predictive model of claylick distribution matched our reported
range well, with precipitation of warmest quarter, land cover, temperature seasonality, and distance from the ocean
being most important predictors of claylick presence. Twenty-six of the region’s 46 parrot species visited claylicks.
Species differed greatly in their lick use, but body size, dietary breadth, abundance and other traits were poor
predictors of lick use. We are confident that our survey identified the distribution of major parrot claylicks in South
America, although less conspicuous parrot geophagy may occur elsewhere. We suggest that claylick distribution
reflects both underlying geology (allowing claylick formation in only some regions) and the physiological need for
geophagy among parrots in different parts of the continent. Data on the latter are inconclusive, but we argue that
parrot claylick distribution supports the contention that geophagy is related more to sodium deficiencies than to
protection from dietary toxins.
Le concept de niche imprègne l’écologie. Comme le concept de fitness en biologie évolutive, c’est un concept central, au sens parfois peu explicité, apte à subir des glissements, jusqu’à finalement pouvoir être qualifié de tautologique... more
Le concept de niche imprègne l’écologie. Comme le concept de fitness en biologie évolutive, c’est un concept central, au sens parfois peu explicité, apte à subir des glissements, jusqu’à finalement pouvoir être qualifié de tautologique (Griesemer 1992). Comme définition préliminaire, disons, sans préciser davantage, que la niche est ce qui décrit l’écologie d’une espèce, ce qui peut signifier son rôle dans l’écosystème, son habitat, etc. Le concept, inspiré par la biologie darwinienne, a connu une fortune croissante au cours du XXe siècle, à la croisée des disciplines écologiques en développement, avant de tomber en disgrâce dans les années 1980 (Chase & Leibold 2003). Dans une première partie, nous retraçons l’histoire du concept et de ses sens, de ses diverses fortunes et infortunes. Dans une deuxième partie, nous examinons plus précisément les rapports que le concept entretient avec les explications de la coexistence et de la diversité. Dans une troisième partie, nous exposons la récente controverse entre la théorie basée sur le concept de niche et la théorie neutre, et discutons son bien-fondé. En conclusion, nous revenons sur les vertus et difficultés des différents sens du concept.
- by Richard Sibly and +1
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- Water, Calcium, Ecology, Daphnia
This paper describes a series of experiments in creating autonomous drawing robots that generate aesthetically interesting and engaging drawings. Based on a previous method for multiple software agents that mimic the biological process of... more
This paper describes a series of experiments in creating autonomous drawing robots that generate aesthetically interesting and engaging drawings. Based on a previous method for multiple software agents that mimic the biological process of niche construction, the challenge in this project was to re-interpret the implementation of a set of evolving software agents into a physical robotic system. In this new robotic system, individual robots try to reinforce a particular niche defined by the density of the lines drawn underneath them. The paper also outlines the role of environmental interactions in determining the style of drawing produced.
Although the role of macroinvertebrates in the nutrient cycling of the Indo-Pacific mangrove ecosystems is now a paradigm of ecological research, most of the research and scientific assumptions deal with decapod crustaceans alone.... more
Although the role of macroinvertebrates in the nutrient cycling of the Indo-Pacific mangrove ecosystems is now a paradigm of ecological research, most of the research and scientific assumptions deal with decapod crustaceans alone. However, decapods are not the only representatives of mangrove macrobenthos and in certain mangals they are surely outnumbered by gastropods, especially by potamidids of the genus Terebralia. This paper aims at bridging the gap in the knowledge of the ecological role of the largest and most abundant potamidid species of the Indo-Pacific mangals, the semiterrestrial T. palustris. In particular we studied size structure and distribution in relation to micro-environmental factors and feeding ecology, both in terms of diet composition and grazing rate, of two populations of this gastropod colonising a Kenyan mangrove creek. In contrast to what has been described by various authors concerning other mangals, in our study site juveniles and adults of T. palustris were present throughout the whole forest, from the landward belt to the seaward fringe, locally reaching very high densities at various levels. Both life stages showed a preference for patches characterised by soil with high organic content; thus the habitat of juveniles largely overlapped with that of the adults, although they are known to occupy different ecological niches. Indeed, gut-content analysis confirmed that juveniles are detritivorous and adults are mainly leaf-litter consumers. In situ experiments on the grazing activity of the adult snails showed that, in contrast to the litter-consuming crabs, they feed in every light and tidal condition, for an hourly consumption rate of ~0.65 g per snail. Considering an average density of about 10.5 adults m−2, it is estimated that a total of 10.5 leaves m−2 are removed by adult snails in each tidal cycle (i.e. about every 6 h). T. palustris is the only leaf consumer capable of searching for food under water during high tide and is responsible for the removal of a great quantity of mangrove litter. The results of the present study strongly suggest that T. palustris plays a major role in the food web, mangrove litter degradation and nutrient cycling of the Kenyan mangal.
Many endemic tree species have important scientific, ecological and economic value but the scarcity of information about their biological and ecological features makes it difficult to develop conservation strategies for them. A four-step... more
Many endemic tree species have important scientific, ecological and economic value but the scarcity of information about their biological and ecological features makes it difficult to develop conservation strategies for them. A four-step approach is presented to address this problem, based on the analysis of data collected in a limited-duration field study: (1) Data collected are used to analyse the ecological niche, population structure and regeneration status of the species in question. (2) Several IUCN Red List (RL) parameters, useful for assessing the species’ risk of extinction, are measured, including population counts, number of locations, extent and area of occurrence. (3) The IUCN RL parameters are used together with the other information gathered to set preliminary conservation priorities. (4) The analysis of utilization pattern is used to develop conservation actions specific to the environmental and socio-economic context. To test the applicability of this approach Boswellia spp. of Socotra island were analysed. Ground-rooted species (B. ameero, B. elongata and B. socotrana) were the most abundant and widespread and, according to the spatial analysis, were characterised by a geo-altitudinal zonation. However, the Weibull functions fitted on their stem diameters, and the absence or presence of only a small number of saplings highlighted a poor regeneration status. In the absence of conservation actions, these species will probably be subject to a progressive decline because of uncontrolled grazing. Of the four cliff-rooted species, which grow in sites that are less accessible to livestock, two (B. popoviana and B. dioscorides) were of lower conservation priority and may become the most numerically abundant. Conversely, the other two (B. nana and B. bullata), which may be threatened by stochastic events because of their reduced populations and small number of locations, were considered of very high priority. Different conservation actions were then identified for each species. In particular, for Boswellia species producing gum, the conservation-through-use action was discussed as a potential option.
- by Fabio Attorre and +1
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- Spatial Analysis, Ecology, Biodiversity, Ecological Niche Modeling
The diversity of life is ultimately generated by evolution, and much attention has focused on the rapid evolution of ecological traits. Yet, the tendency for many ecological traits to instead remain similar over time [niche conservatism... more
The diversity of life is ultimately generated by evolution, and much attention has focused on the rapid evolution of ecological traits. Yet, the tendency for many ecological traits to instead remain similar over time [niche conservatism (NC)] has many consequences for the fundamental patterns and processes studied in ecology and conservation biology. Here, we describe the mounting evidence for the importance of NC to major topics in ecology (e.g. species richness, ecosystem function) and conservation (e.g. climate change, invasive species). We also review other areas where it may be important but has generally been overlooked, in both ecology (e.g. food webs, disease ecology, mutualistic interactions) and conservation (e.g. habitat modification). We summarize methods for testing for NC, and suggest that a commonly used and advocated method (involving a test for phylogenetic signal) is potentially problematic, and describe alternative approaches. We suggest that considering NC: (1) focuses attention on the within-species processes that cause traits to be conserved over time, (2) emphasizes connections between questions and research areas that are not obviously related (e.g. invasives, global warming, tropical richness), and (3) suggests new areas for research (e.g. why are some clades largely nocturnal? why do related species share diseases?).
Species distribution model is the term most frequently used in ecological modelling, but other authors used instead predictive habitat distribution model or species-habitat models. A consensual ecological modelling terminology that avoids... more
Species distribution model is the term most frequently used in ecological modelling, but other authors used instead predictive habitat distribution model or species-habitat models. A consensual ecological modelling terminology that avoids misunderstandings and takes into account the ecological niche theory does not exist at present. Moreover, different studies differ in the type of niche that is represented by similar distribution models. I propose to use as standard ecological modelling terminology the terms “ecological niche”, “potential niche”, “realized niche” models (for modelling their respective niches), and “habitat suitability map” (for the output of the niche models). Therefore, the user can understand more easily that models always forecast species’ niche and relate more closely the different types of niche models.► Species distribution model is the term most frequently used in ecological modelling. ► I propose a standard ecological modelling terminology for avoiding misunderstandings. ► The term ecological niche model includes mechanistic and correlative models. ► The terms potential and realized niche models are for the respective species niches. ► Habitat suitability map should be used for the output of the models.
Knowledge about the current distribution of threatened and/or understudied species is a fundamental component of conservation biology. Mapping species distributions based on recent known occurrences is particularly important for those... more
Knowledge about the current distribution of
threatened and/or understudied species is a fundamental
component of conservation biology. Mapping species distributions
based on recent known occurrences is particularly
important for those that are rare or declining. Too
often, cryptic species go undetected throughout parts of
their range, whereas others just receive less research
attention. We used contemporary presence data for the
Pallas’s cat (Otocolobus manul), a small cryptic felid, to
characterize potential rangewide and regional habitat for
the species and identify those abiotic and biotic variables
most influencing its distribution. Several regions lacking
contemporary occurrence records contain potential habitat
for Pallas’s cats, including the Koh-i-Baba Mountains of
Afghanistan, Qinghai-Tibetan Plateau, steppes of Inner
Mongolia, Kunlun Mountains of China, and Tian Shan and
Pamir Mountains of Kyrgyzstan, Tajikistan, and China.
Some of these areas have not been included in prior rangewide
distribution assessments. The distribution of pikas
(Ochotona spp.), small mammals that likely represent a
critical prey species everywhere they are sympatric, was
the most important factor affecting the Pallas’s cat’s distribution.
This suggests Pallas’s cats may be prey specialists,
and that pika presence and habitat are critical
considerations for future Pallas’s cat surveys and in the
development of regional conservation actions.
Hundreds of marine organisms including algae, phytoplankton, zooplankton, sponges, Cnidarians, mollusks, worms, arthropods, and fish species have already migrated via the Suez Canal in Egypt since the Grand Opening in November 1869. The... more
Hundreds of marine organisms including algae, phytoplankton, zooplankton, sponges, Cnidarians, mollusks, worms, arthropods, and fish species have already migrated via the Suez Canal in Egypt since the Grand Opening in November 1869. The Lessepsian migration takes place mostly from the Red Sea to the Mediterranean. However, few species migrated in the opposite direction (the Anti-Lessepsian migration) (Golani and Ben-Tuvia, 1995; Golani et al., 2002). The factors that facilitate the mainly northwardly transport to the Mediterranean were well described by Por (1971, 1978) who claims that high salinity and high temperature in the Levant Basin of the Mediterranean increase the chances of success of Red Sea invaders. The fact that the Red Sea contains far more species when compared with the temperate fauna in the Mediterranean also contributes to the predominance of Red Sea organisms among Lessepsian migrants. In addition, the high salinities of the two bitter lakes along the canal, reaching 48‰ (Morcos and Messieh, 1973), make the traverse harder for Mediterranean than for Red Sea species, since the latter is considerably more saline. The fact that Indo-Pacific organisms show more versatile adaptation to various ecological niches helps them to compete successfully with Mediterranean species and occupy vacant ecological niches as well (Por, 1971). Other important reasons to the northern transport are the winds and the northward water current leading from the southern end of the canal to its north. These streams support species migration as animal eggs, larvae, and juveniles, and probably algal spores as well (Madl, 1999). International maritime traffic also plays an important role (as a transportation vector) conveying marine species all around the world through the ships ballast water (Nehring, 2002, 2005; Streftaris et al., 2005) or attached to the ships’ hulls (Verlaque et al., in press).
Ecnomiohyla miotympanum es una rana endémica de México, representativa de los ecosistemas montañosos, considerada como controlador de plagas e indicador de la calidad del hábitat. Son escasos los estudios en esta especie, se desconoce su... more
Ecnomiohyla miotympanum es una rana endémica de México, representativa de los ecosistemas montañosos, considerada como controlador de plagas e indicador de la calidad del hábitat. Son escasos los estudios en esta especie, se desconoce
su estatus de conservación y riesgo de extinción, por lo tanto los estudios de nicho ecológico son importantes para entender los parámetros ecológicos que esta especie requiere para el desarrollo de sus poblaciones y que apoyen los programas para el manejo de su hábitat. El objetivo de este estudio fue desarrollar y analizar el modelo de nicho ecológico de E. miotympanum mediante dos software DIVA-GIS y MaxEnt: estos programas usan datos de presencia de la especie y variables ambientales del polígono donde se desarrolla el estudio de la especie; la finalidad fue obtener de manera gráfica (mapa) las probabilidades de predicción e idoneidad del ambiente donde se desarrolla la especie; asimismo, se obtuvieron las variables ambientales de mayor importancia para el desarrollo del nicho ecológico de la especie. Un mapa fue desarrollado en DIVA-GIS para determinar la frecuencia de la presencia de E. miotympanum en los estados de la república mexicana, información que permitió ampliar su área de distribución reportada originalmente y se reportan nuevos registros para diferentes estados mexicanos. Otro mapa, denominado distribución actual, se elaboró con los puntos
georreferenciados para la especie que fueron obtenidos de la base de datos consultada. Tres mapas se elaboraron con MaxEnt usando el 30, 70 y 100% de los datos de presencia de la especie, determinando que la cantidad de muestras no afecta la predicción del modelo de nicho ecológico de la especie, por lo que el modelo resultó robusto. La precipitación fue la condición ambiental de más importancia del nicho ecológico de E. miotympanum, resultado de su biología y del hábitat en el que se desarrolla: bosque mesófilo de montaña. Se generaron recomendaciones de aquellas áreas prioritarias para la conservación de la especie in situ, que en consecuencia apoyará la conservación del hábitat de esta especie.
This article develops an analysis of disability according to which disabling conditions are properties of organisms embedded in sets of environments. We begin by presenting the three mainstream accounts of disability—the medical, social,... more
This article develops an analysis of disability according to which disabling conditions are properties of organisms embedded in sets of environments. We begin by presenting the three mainstream accounts of disability—the medical, social, and interactionist models—and rehearsing some known limitations. We argue that, because of their primary focus on etiology, all three models share, more or less implicitly, a problematic assumption. This is the tenet that disabilities are individual properties. The second part of the essay presents an 'ecological' interpretation of disability, inspired by classic and contemporary research on biological niches. Our proposal preserves many insights underlying extant approaches, while allowing a more accurate characterization of the nature and experience of disability. We conclude by drawing some general implications of our analysis.
This thesis is an investigation on the niche concept and related theoretical frameworks: niche theory and neutral theory in ecology, niche construction theory in evolutionary biology, and the stem cell niche in intraorganism ecology. The... more
This thesis is an investigation on the niche concept and related theoretical frameworks: niche theory and neutral theory in ecology, niche construction theory in evolutionary biology, and the stem cell niche in intraorganism ecology. The first chapter traces the history of the niche concept and compares niche theory to a competing theory, the neutral theory of biodiversity. The niche concept appears to be an explanans of species diversity and ecosystem structure. The second chapter compares standard evolutionary theory to the theory of niche construction, in which an organism can affect its environment and thus influence the selection to come. I show how to characterize this confrontation in terms of the time scales of the processes involved, which allows us to identify the range of validity truly unique to niche construction theory more explicitly than it has been in the past. The third chapter develops the research of the previous two chapters in the modeling of a gene therapy as a process of competition and ecological niche construction by cells. I present a family of models applied to different time scales of cellular dynamics , among which the careful modeler cannot choose without specific experimental results. I conclude on the conceptions of the relationship between an organism and its environment attached to the various facets of the concept.
Neanderthals and their predecessors co-existed with a number of large carnivores. Hence, the Neanderthal predatory niche was shaped by their co-existence with carnivores exploiting the same categories of prey. Here, I analyze cave hyena... more
Neanderthals and their predecessors co-existed with a number of large carnivores. Hence, the Neanderthal predatory niche was shaped by their co-existence with carnivores exploiting the same categories of prey. Here, I analyze cave hyena prey deposits and Neanderthal bone assemblages dating to MIS 3 and 4 to determine the degree of niche overlap between Neanderthals and large carnivores. The results suggest that although the exploited species overlap between Neanderthals and cave hyenas, the emphasis of exploitation was on different animal groups.