Niche Research Papers - Academia.edu (original) (raw)

Resumen en: The significant purpose of the author in the Introduction of a research article is to convince the reader about the importance of the work to be presente...

The bicentennial celebration of the inception of Frankenstein invites the present view of Victor Frankenstein and his fateful deci- sion to destroy an unfinished female creature. The act itself was impulsive (caused by a “sensation of... more

The bicentennial celebration of the inception of Frankenstein invites the present view of Victor Frankenstein and his fateful deci- sion to destroy an unfinished female creature. The act itself was impulsive (caused by a “sensation of madness”), but it was preceded by agonized reasoning that would be familiar to any student of ecology or evolutionary biology. Here, we present a formal treatment of Frankenstein’s reasoning and show that his rationale for denying a mate to his male creation has empirical justification. Our results suggest that the decision was prudent because it averted our own extinction by competitive exclusion. We conclude by suggesting that the central horror of Mary Shelley’s novel lies in its prescient command of foundational concepts in ecology and evolution.

When does a human being begin to exist? We argue that it is possible, through a combination of biological fact and philosophical analysis, to provide a definitive answer to this question. We lay down a set of conditions for being a human... more

When does a human being begin to exist? We argue that it is possible, through a combination of biological fact and philosophical analysis, to provide a definitive answer to this question. We lay down a set of conditions for being a human being, and we determine when, in the course of normal fetal development, these conditions are first satisfied.

The availability of detailed environmental data, together with inexpensive and powerful computers, has fueled a rapid increase in predictive modeling of species environmental requirements and geographic distributions. For some species,... more

The availability of detailed environmental data, together with inexpensive and powerful computers, has fueled a rapid increase in predictive modeling of species environmental requirements and geographic distributions. For some species, detailed presence/absence occurrence data are available, allowing the use of a variety of standard statistical techniques. However, absence data are not available for most species. In this paper, we introduce the use of the maximum entropy method (Maxent) for modeling species geographic distributions with presence-only data. Maxent is a general-purpose machine learning method with a simple and precise mathematical formulation, and it has a number of aspects that make it well-suited for species distribution modeling. In order to investigate the efficacy of the method, here we perform a continental-scale case study using two Neotropical mammals: a lowland species of sloth, Bradypus variegatus, and a small montane murid rodent, Microryzomys minutus. We compared Maxent predictions with those of a commonly used presence-only modeling method, the Genetic Algorithm for Rule-Set Prediction (GARP). We made predictions on 10 random subsets of the occurrence records for both species, and then used the remaining localities for testing. Both algorithms provided reasonable estimates of the species' range, far superior to the shaded outline maps available in field guides. All models were significantly better than random in both binomial tests of omission and receiver operating characteristic (ROC) analyses. The area under the ROC curve (AUC) was almost always higher for Maxent, indicating better discrimination of suitable versus unsuitable areas for the species. The Maxent modeling approach can be used in its present form for many applications with presence-only datasets, and merits further research and development.

The multi-level perspective (MLP) is a prominent transition framework. The MLP posits that transitions come about through interaction processes within and among three analytical levels: niches, socio-technical regimes and a... more

The multi-level perspective (MLP) is a prominent transition framework. The MLP posits that transitions come about through interaction processes within and among three analytical levels: niches, socio-technical regimes and a socio-technical landscape. This systematic review provides an overview on the use of the MLP in research on agro-food sustainability transitions. In particular, it analyses the understanding, conceptualisation and operationalisation of niches, regimes and landscapes. Niches considered in the selected papers include agro-ecology, organic agriculture, permaculture, conservation agriculture, integrated farming, and alternative food networks. Regime refers to industrial, conventional agriculture. The researched regime is often not clearly described and its operationalisation is a matter of deliberation. Landscape level is generally overlooked; when it is considered it refers to international trends and developments. Many scholars highlight the inadequacy of transition pathways in the MLP for the agro-food sector. Moreover, transition impacts are rarely addressed and the research field generally overlooks the analysis of the sustainability of niches and, consequently, of transitions. Research on transitions in the agro-food sector borrows from the MLP its generalizability and poor empirical operationalisation of niche, regime and landscape concepts. Therefore, integrative conceptualisation and operationalisation of the MLP elements is required to accommodate the complexity of sustainability transition processes and the peculiarities of the agro-food system.

The contribution of deterministic and stochastic processes to species coexistence is widely debated. With the introduction of powerful statistical techniques, we can now better characterise different sources of uncertainty when... more

The contribution of deterministic and stochastic processes to species coexistence is widely debated. With the
introduction of powerful statistical techniques, we can now better characterise different sources of uncertainty
when quantifying niche differentiation. The theoretical literature on the effect of stochasticity on coexistence,
however, is often ignored by field ecologists because of its technical nature and difficulties in its application.
In this review, we examine how different sources of variability in population dynamics contribute to
coexistence. Unfortunately, few general rules emerge among the different models that have been studied to
date. Nonetheless, we believe that a greater understanding is possible, based on the integration of coexistence
and population extinction risk theories. There are two conditions for coexistence in the presence of
environmental and demographic variability: (1) the average per capita growth rates of all coexisting species must
be positive when at low densities, and (2) these growth rates must be strong enough to overcome negative
random events potentially pushing densities to extinction. We propose that critical tests for species coexistence
must account for niche differentiation arising from this variability and should be based explicitly on notions of
stability and ecological drift.

We propose a multivariate approach to the study of geographic species distribution which does not require absence data. Building on Hutchinson's concept of the ecological niche, this factor analysis compares, in the multidimensional space... more

We propose a multivariate approach to the study of geographic species distribution which does not require absence data. Building on Hutchinson's concept of the ecological niche, this factor analysis compares, in the multidimensional space of ecological variables, the distribution of the localities where the focal species was observed to a reference set describing the whole study area. The first factor extracted maximizes the marginality of the focal species, defined as the ecological distance between the species optimum and the mean habitat within the reference area. The other factors maximize the specialization of this focal species, defined as the ratio of the ecological variance in mean habitat to that observed for the focal species. Eigenvectors and eigenvalues are readily interpreted and can be used to build habitat-suitability maps. This approach is recommended in situations where absence data are not available (many data banks), unreliable (most cryptic or rare species), or meaningless (invaders). We provide an illustration and validation of the method for the alpine ibex, a species reintroduced in Switzerland which presumably has not yet recolonized its entire range.

The present study was carried out from 2001 to 2005, with the objective of analyzing the diet of Leopardus geoffroyi in extreme southern Brazil, through analyses of stomach contents and scats. The importance of each prey type found in the... more

The present study was carried out from 2001 to 2005, with the objective of analyzing the diet of Leopardus geoffroyi in extreme southern Brazil, through analyses of stomach contents and scats. The importance of each prey type found in the scats (n=66) was determined from the frequency of occurrence and percentage of occurrence. In the stomachs (n=9), the importance of each prey was determined using Pianka's index of relative importance (IRI). The food spectrum of L. geoffroyi included mammals, birds, serpents, amphibians and insects. Mammals were the most abundant items, present in 95.5% of the scats and representing 74.4% of the total prey, reaching an IRI of 13296.3 in the stomachs. The principal prey types found in the stomachs and scats were small rodents (Cavia spp., Oligoryzomys spp., Necromys spp. and Holochilus brasiliensis) and large-sized rodents (Myocastor coypus), of terrestrial, arboreal or semi-aquatic habit. Probably, the high percentage of these prey items in the diet is related to their availability and abundance. The index of niche breadth was low in both the stomach and scat analyses (respectively, Bsta=0.18 and 0.17), demonstrating the high degree of specialization of these cats.Die Fressgewohnheiten der Kleinfleckkatze (Leopardus geoffroyi) im südlichen BrasilienLeopardus geoffroyi ist eine kleine Katze, die in den gemäßigten und subtropischen Breiten Südamerikas zu Hause ist. Sie ist sowohl in Brasilien als auch weltweit auf der Liste der bedrohten Arten zu finden. Im Staat Rio Grande do Sul wird sie im Status „vulnerable” geführt. Die aktuelle Studie, die von 2001 bis 2005 durchgefuehrt wurde, hatte zum Ziel, die Ernährungsgewohnheiten von Leopardus geoffroyi anhand von Mageninhalten und Kot zu analysieren. Die Wichtigkeit jeder Beuteart, die im Kot gefunden wurde (n=66), wurde anhand der Häufigkeit ihres Vorkommens (Prozentsatz des Kots, der einen bestimmten Beuteanteil enthielt) und des Prozentsatzes ihres Vorkommens (Prozentsatz der Gesamtnahrungsmittelanteile) bestimmt. In den Mägen (n=9) wurde der Wert jedes Beutetieres mit dem Piankas Index des relativen Wertes (IRI) festgestellt. Das Nahrungsspektrum von L. geoffroyi enthielt Säugetiere, Vögel, Schlangen, Amphibien und Insekten. Säugetiere machten den grössten Anteil aus. Sie waren in 95.5% des Kots vorhanden und stellten 74.4% der erbeuteten Tiere dar. Damit erreichten sie einen Wert von relativer Bedeutung von 13296.3 in den Mägen. Die Hauptbeutetiere, die in den Mägen und im Kot gefunden wurden, waren kleine Nagetiere (Cavia spp., Oligoryzomys spp., Necromys spp. und Holochilus brasiliensis) und mittlere Nagetiere (Myocastor coypus), mit terrestrischem Lebensraum, auf Bäumen oder in Feuchtgebieten lebend. Wahrscheinlich steht der hohe Anteil dieser Beuteart in Zusammenhang mit ihre hohen Verfügbarkeit. Der Wert an anderen Beutetieren war in den Magen- und Kotanalysen niedrig (jeweils, Bsta=0.18 and 0.17). Damit wird der hohe Grad der Spezialisierung in der Ernährungsweise der Wildkatze deutlich.

Mechanistic models of community assembly state that biotic and abiotic filters constrain species establishment through selection on their functional traits. Predicting this assembly process is hampered because few studies directly... more

Mechanistic models of community assembly state that biotic and abiotic filters constrain species establishment through selection on their functional traits. Predicting this assembly process is hampered because few studies directly incorporate environmental measurements and scale up from species to community level and because the functional traits' significance is environment dependent. We analyzed community assembly by measuring structure, environmental conditions, and species traits of secondary forests in a species-rich tropical system. We found, as hypothesized, that community structure shaped the local environment and that strong relationships existed between this environment and the traits of the most successful species of the regeneration communities. Path and multivariate analyses showed that temperature and leaf traits that regulate it were the most important factors of community differentiation. Comparisons between the trait composition of the forest's regeneration, juvenile, and adult communities showed a consistent community assembly pattern. These results allowed us to identify the major functional traits and environmental factors involved in the assembly of dry-forest communities and demonstrate that environmental filtering is a predictable and fundamental process of community assembly, even in a complex system such as a tropical forest.

This paper argues that evolutionary thinking and modeling can contribute to the emerging research on sustainability transitions and their management. Evolutionary theory provides a range of concepts and mechanisms that are useful in... more

This paper argues that evolutionary thinking and modeling can contribute to the emerging research on sustainability transitions and their management. Evolutionary theory provides a range of concepts and mechanisms that are useful in making existing theorizing about transitions more precise and complete. In particular, we will discuss how the multi-level, multi-phase, co-evolutionary, and social learning dynamics underlying transitions can be addressed in evolutionary models. In addition, evolutionary theorizing offers suggestions for extending current theoretical frameworks of transitions. Group selection provides a good example. We review the small set of formal evolutionary models of sustainability transitions, and show that existing formal evolutionary models of technological, social and institutional change can provide useful inputs to transition research and management.

Manipulative field experiments assessing the importance of interspecific competition on the dynamics of parasitoid populations and the impact of multiple parasitoids on host populations are virtually absent from the ecological literature.... more

Manipulative field experiments assessing the importance of interspecific competition on the dynamics of parasitoid populations and the impact of multiple parasitoids on host populations are virtually absent from the ecological literature. We report findings from such experiments assessing competitive interactions among three species of parasitoids (Hymenoptera: Aphelinidae) of the silverleaf whitefly Bemisia argentifolii Bellows & Perring (Homoptera: Aleyrodidae), a pestiferous species of worldwide importance. The parasitoids used in the study (Encarsia pergandiella Howard, Eretmocerus mundus Mercet, and Encarsia formosa Gahan) encompass the range of life histories found within Aphelinidae, and they exhibit a high degree of niche overlap. The objectives of our studies were (1) to investigate the occurrence of interspecific competition among the whitefly parasitoids, (2) to quantify shifts in resource utilization patterns as influenced by experimental manipulations of the parasitoid assemblage, and (3) to assess the impact of interspecific competition on the ability of the parasitoids to suppress their host populations.

In spite of tremendous advances in medicine, many retinal neurodegenerative diseases are still destined to result in blindness. The advances in stem cell therapy (SCT) in the last decade are very promising in this regard. Currently, the... more

In spite of tremendous advances in medicine, many retinal neurodegenerative diseases are still destined to result in blindness. The advances in stem cell therapy (SCT) in the last decade are very promising in this regard. Currently, the successful results in the use of embryonic stem cells (ESC) in patients with Stargardt and age-related macular degeneration (AMD) are encouraging; but cautious optimism is strongly advised. There are still several important challenges even from basic molecular mechanisms which need to be overcome in order for SCT to be a viable option for physicians. This article summarizes the current status and future prospects of SCT in retinal neurodegenerative disease.

Diet is a fundamental aspect of the ecological niche of amphibians and usually varies intra-specifically in response to extrinsic environmental and intrinsic individual factors. Phenotypic variations among individuals can generate... more

Diet is a fundamental aspect of the ecological niche of amphibians and
usually varies intra-specifically in response to extrinsic environmental and intrinsic
individual factors. Phenotypic variations among individuals can generate
intrapopulation differences in trophic resource use, which could have important
ecological and evolutionary implications in amphibian populations. Here, we
studied the intrapopulation dietary variation of the frog Pseudopaludicola pusilla
in an anthropic savanna of the Colombian Caribbean region, considering the
effects of seasonality and sex on the size, amount, prey composition and dietary
individual specialization. We collected 44 adult frogs during the dry season and
46 during the rainy season and analyzed their stomach contents to determine
their dietary composition. Our results indicate that P. pusilla is a generalist and
opportunist predator, feeding mainly on insects of the orders Orthoptera,
Coleoptera and Hymenoptera, which were the most important prey categories
due to their numeric, volumetric and frequency contributions. We observed
seasonal variations regarding volumetric prey composition and the importance
value of each prey category in the populational diet. Individuals of P. pusilla
consume more prey items during the rainy season and bigger prey during the dry
season, but the volume of stomach contents did not vary seasonally. Males and
females of P. pusilla consumed a similar number of prey items, but females
ingested more voluminous prey and had greater volumes of stomach contents
than males. Additionally, we observed a pattern of dietary individual specialization,
which was not related to morphological trade-offs and did not differ among
seasons. These findings contribute to the understanding of the seasonal dynamics of the use of trophic resources by anurans and the effect of sex on dietary characteristics of P. pusilla, in environments strongly influenced by climatic seasonality.

To elucidate whether dipterocarp species, dominant late-successional species of tropical forests in Southeast Asia, actually have a disadvantage when planted on open site in terms of their photosynthetic characteristics, we investigated... more

To elucidate whether dipterocarp species, dominant late-successional species of tropical forests in Southeast Asia, actually have a disadvantage when planted on open site in terms of their photosynthetic characteristics, we investigated photosynthesis in dipterocarp seedlings planted in the open on degraded sandy soils in southern Thailand. These species were compared with seedlings of Acacia mangium Willd., a fast-growing tropical leguminous tree, which is often planted on degraded open site in Southeast Asia. The dipterocarp seedlings had an irradiance-saturated net photosynthetic rate (P N ), stomatal conductance (g s ), carboxylation efficiency, and photosynthetic capacity comparable to or superior to those of A. mangium. In particular, seedlings of Dipterocarpus obtusifolius Teijsm. ex Miq. showed an irradiance-saturated P N of 21 µmol m -2 s -1 , a value higher than any previously reported for a dipterocarp species, accompanied by high g s (0.7 mol m -2 s -1 ) and high photosynthetic capacity. Thus dipterocarp species do not necessarily have a disadvantage in terms of their photosynthetic characteristics on open sites with degraded sandy soils. Abbrevations: C i -internal CO 2 concentration; Chl -chlorophyll; g s -stomatal conductance; P N -net photosynthetic rate; PPFDphotosynthetic photon flux density; PS2 -photosystem 2; R D -dark respiration rate.

In the recent past, availability of large data sets of species presences has increased by orders of magnitude. This, together with developments in geographical information systems and statistical methods, has enabled scientists to... more

In the recent past, availability of large data sets of species presences has increased by orders of magnitude. This, together with developments in geographical information systems and statistical methods, has enabled scientists to calculate, for thousands of species, the environmental conditions of their distributional areas. The profiles thus obtained are obviously related to niche concepts in the Grinnell tradition, and separated from those in Elton’s tradition. I argue that it is useful to define Grinnellian and Eltonian niches on the basis of the types of variables used to calculate them, the natural spatial scale at which they can be measured, and the dispersal of the individuals over the environment. I use set theory notation and analogies derived from population ecology theory to obtain formal definitions of areas of distribution and several types of niches. This brings clarity to several practical and fundamental questions in macroecology and biogeography.

Tree and shrub integration has been promoted as a means of enhancing rural livelihoods through sustaining watershed provision of services and products, especially in Ethiopia. However, research to support this effort has been limited.... more

Tree and shrub integration has been promoted as a means of enhancing rural livelihoods through sustaining watershed provision of services and products, especially in Ethiopia. However, research to support this effort has been limited. This study was conducted in Borodo watershed in central Ethiopia, to identify constraints to the process of tree and shrub integration in the watersheds. A household survey was conducted, supplemented with focus group discussions (FGDs), key informant interview and field observations. A total of 31tree and 11 shrub species were identified in different niches in the watershed. The key constraints to tree and shrub species integration included shortage of arable land, soil cracking, free grazing, lack of seedlings of desired species and water-logging. The main catalysts to the integration were availability of information on improved integration and cash for investment in the required activities, easy land certification and market opportunity for tree and...

The multi-level perspective (MLP) is a prominent transition framework. The MLP posits that transitions come about through interaction processes within and among three analytical levels: niches, socio-technical regimes and a... more

The multi-level perspective (MLP) is a prominent transition framework. The MLP posits that transitions come about through interaction processes within and among three analytical levels: niches, socio-technical regimes and a socio-technical landscape. This systematic review provides an overview on the use of the MLP in research on agro-food sustainability transitions. In particular, it analyses the understanding, conceptualisation and operationalisation of niches, regimes and landscapes. Niches considered in the selected papers include agro-ecology, organic agriculture, permaculture, conservation agriculture, integrated farming, and alternative food networks. Regime refers to industrial, conventional agriculture. The researched regime is often not clearly described and its operationalisation is a matter of deliberation. Landscape level is generally overlooked; when it is considered it refers to international trends and developments. Many scholars highlight the inadequacy of transitio...

Traditional classifications of developmental patterns of marine benthic invertebrates are based on combinations of embryological (direct or indirect development) and ecological (such as nutritional source or habitat) characteristics.... more

Traditional classifications of developmental patterns of marine benthic invertebrates are based on combinations of embryological (direct or indirect development) and ecological (such as nutritional source or habitat) characteristics. Different schemes have been proposed for different reasons, relating to ecology, evolution and / or development. However, these classifications contain interconnected characters that do not efficiently discriminate between developmental patterns and, thus, do not fully apply to either ecological or embryological studies. An ecological multifactor classification based on three independent two-state characters (pelagic / benthic, free / protected, and feeding / non-feeding) is proposed. It discriminates between eight developmental patterns and can encompass any ecological pattern of development among marine benthic invertebrates.

The Mahalanobis distances have been introduced in habitat selection studies for the estimation of environmental suitability maps (ESMs). The pixels of raster maps of a given area correspond to points in the multidimensional space defined... more

The Mahalanobis distances have been introduced in habitat selection studies for the estimation of environmental suitability maps (ESMs). The pixels of raster maps of a given area correspond to points in the multidimensional space defined by the mapped environmental variables (ecological space). The Mahalanobis distances measure the distances in this space between these points and the mean of the ecological niche (i.e., the hypothesized optimum for the species) regarding the structure of the niche. The map of these distances over the area of interest is an estimated ESM. Several authors recently noted that the use of a single optimum for the niche of a species may lead to biased predictions of animal occurrence. They proposed to use instead a minimum set of basic habitat requirements, found by partitioning the Mahalanobis distances into a restricted set of biologically meaningful axes. However, the statistical approach they proposed does not take into account the environmental conditions on the area where the niche was sampled (i.e., the environmental availability), and we show that including this availability is necessary. We used their approach as a basis to develop a new exploratory tool, the Mahalanobis distance factor analysis (MADIFA), which performs an additive partitioning of the Mahalanobis distances taking into account this availability. The basic habitat requirements of a species can be derived from the axes of the MADIFA. This method can also be used to compute ESMs using only this small number of basic requirements, therefore including only the biologically relevant information. We also prove that the MADIFA is complementary to the commonly used ecological-niche factor analysis (ENFA). We used the MADIFA method to analyze the niche of the chamois Rupicapra rupicapra in a mountainous area. This method adds to the existing set of tools for the description of the niche.

0[ Ecomorphological studies have described local bat communities as densely!packed species assemblages arising from non!deterministic processes[ Together with the obser! vation that insectivorous bats readily exploit patchy\ often... more

0[ Ecomorphological studies have described local bat communities as densely!packed species assemblages arising from non!deterministic processes[ Together with the obser! vation that insectivorous bats readily exploit patchy\ often unlimited trophic resources\ this has even led to the claim that partitioning of niche space may be absent[ However\ the paucity of data on resource exploitation per se among bat guilds rarely allows these assertions to be veri_ed[ In particular\ the mechanisms allowing the co! existence of similar species have proved di.cult to determine[ 1[ As a subset of an insectivorous guild\ the vespertilionid bats Myotis myotis and M[ blythii o}er an opportunity to examine this question[ Genetically closely!related\ they are morphologically almost identical[ Yet\ as established by faecal analysis\ they exploit distinct trophic niches\ preying upon ground! and grass!dwelling prey taxa\ respectively[ The distinct habitat requirements of their basic prey suggest that eco! logical segregation may stem primarily from a di}erential allocation of foraging space[ 2[ The present study tests the hypothesis that sympatric M[ myotis and M[ blythii segregate spatially to an extent which prevents competitive interference[ I performed radio!tracking on Swiss sympatric populations[ Using multivariate analyses and ran! domized contingency table procedures\ I looked for "i# habitat overlap and overall inter!speci_c di}erences in habitat choice\ and "ii# the habitat preferences exhibited by individuals when foraging within their own feeding areas[ 3[ Primary foraging habitats were largely species!speci_c[ Not only were they spatially segregated\ but they also di}ered structurally[ All habitats selected by M[ myotis o}ered a high accessibility to ground!dwelling prey "freshly!cut meadows\ mown grass in intensively cultivated orchards\ forests without undergrowth#\ whereas grassland predominated in all habitats of M[ blythii "steppe\ unmown meadows\ pastures#[ This corroborates the predictions drawn from dietary niches[ 4[ This study shows that re_ned mechanisms of resource partitioning\ not predictable by the study of morphological characters or echolocation alone\ may still account for the organization of parts of insectivorous bat guilds[ It also supports the view that habitat selection may prove to be a major mode of resource allocation amongst similar insectivorous bats\ particularly for species exploiting limited food supplies[

A number of recognized shortfalls currently exist in biology. Th ey are related to 1) a disparity between the species described and the actual number of species; 2) uncertainties in species ’ geographical distribution; 3) scarcity of... more

A number of recognized shortfalls currently exist in biology. Th ey are related to 1) a disparity between the species
described and the actual number of species; 2) uncertainties in species ’ geographical distribution; 3) scarcity of species
abundance data and 4) a lack of evolutionary data. Here, we discuss how attempts to solve the Eltonian shortfall (scarcity
of knowledge about intra- and interspecifi c interactions, responses of species to environment and the eff ects of species on
ecosystems) based on functional ecology must be aware of the pitfalls of using a Grinnellian view (broad scale) to address
local questions (Eltonian scale). Since the characterization of species ’ requirements and their eff ects on the environment
(Eltonian niche) is based on functional traits, it is important to recognize that the Grinnellian niche is focused on the
requirements but not the eff ect of species on a given habitat. By neglecting the dichotomy between the Eltonian and
Grinnellian niches, choosing traits based on large-scale datasets to address local questions to describe the niche of a species
may lead to two pitfalls. Th e fi rst applies to situations where traits that may predict potential distribution and coexistence
at large scales (Grinnellian view) are often not suitable for explaining coexistence at local scales (Eltonian view). Since the
Eltonian niche comprises the requirements and impacts of species at a local scale, the second pitfall is that the selection
of traits only based on their signifi cance at coarse scales may ignore the distinction between response and eff ect traits.
We present a theoretical framework that explores the Eltonian shortfall, and discuss possible solutions. We provide a
conceptual basis to aid in the choice of traits with respect to niche concepts and population ecology for dealing with the
Eltonian shortfall.

Common buffelgrass (Cenchrus ciliaris L.) was studied in a field experiment under two fertility levels (0 or 50 kg N ha -1 ), two cutting heights (5 or 15 cm above ground level), two cutting frequencies (21 or 42 days), during a 126 day... more

Common buffelgrass (Cenchrus ciliaris L.) was studied in a field experiment under two fertility levels (0 or 50 kg N ha -1 ), two cutting heights (5 or 15 cm above ground level), two cutting frequencies (21 or 42 days), during a 126 day growing season. Results showed significant highest yields with the least frequent, more severe defoliation. The highest fertility environment was favourable for yield productivity, ash and crude protein content. The effect of the intensity and frequency of defoliation suggests the need to impose appropriate defoliation stress to obtain high yield with better quality.

A lineage of 12 arid land shrubby species in the gymnosperm genus Ephedra (Gnetales) from North America is used to evaluate the influence of climate on speciation. With a long evolutionary history, and a well documented fossil record this... more

A lineage of 12 arid land shrubby species in the gymnosperm genus Ephedra (Gnetales) from North America is used to evaluate the influence of climate on speciation. With a long evolutionary history, and a well documented fossil record this lineage is an ideal model for understanding the process of speciation under a niche conservatism scenario. Using seven DNA molecular markers, Bayesian inference is carried out to uncover sister species and to estimate time of divergence of the lineages. Ecological niche models are generated for four parapatric and sympatric sister species and two analyses of niche evolution are performed, one based on ecological niche models and another using raw data and multivariate analysis. As previous analyses suggest, the diversification of North America Ephedra species may be the result of a recent secondary radiation. Both parapatric and sympatric species diverged mostly in a scenario of climatic niche conservatism. However, we also found strong evidence for niche divergence for one of the sister species pairs (E. californica–E. trifurca). Moreover, the multivariate analysis found environmental differences for some variables between sister species. The estimated divergence time of three pairs of sister species distributed in southwestern North America (E. cutleri–E. aspera, E. californica–E. trifurca and E. torreyana–E. viridis) is inferred to have occurred in the Late Miocene to Pliocene and for the sister species pair E. antisyphilitica–E. coryi distributed in the southern United States and northeastern Mexico, it was inferred from the Pliocene to Pleistocene. The orogenetic and climatic changes documented for these regions related to expansion of arid lands, may have contributed to the diversification in North American Ephedra, rather than adaptations to new climatic conditions.► We inferred relationships and divergence time of North America Ephedra species. ► We compared climatic conditions of sister species using tests of niche evolution. ► Our results mostly suggest climatic niche conservatism, with one exception. ► Divergence time coincides with an increase of arid lands in North America. ► We suggest that diversification is related to habitat expansion.

We applied two-photon polymerization to fabricate 3D synthetic niches arranged in complex patterns to study the effect of mechano-topological parameters on morphology, renewal and differentiation of rat mesenchymal stromal cells. Niches... more

We applied two-photon polymerization to fabricate 3D synthetic niches arranged in complex patterns to study the effect of mechano-topological parameters on morphology, renewal and differentiation of rat mesenchymal stromal cells. Niches were formed in a photoresist with low auto-fluorescence, which enabled the clear visualization of the fluorescence emission of the markers used for biological diagnostics within the internal niche structure. The niches were structurally stable in culture up to three weeks. At three weeks of expansion in the niches, cell density increased by almost 10-fold and was 67% greater than in monolayer culture. Evidence of lineage commitment was observed in monolayer culture surrounding the structural niches, and within cell aggregates, but not inside the niches. Thus, structural niches were able not only to direct stem cell homing and colony formation, but also to guide aggregate formation, providing increased surface-to-volume ratios and space for stem cells to adhere and renew, respectively.

Understanding evolutionary mechanisms is fundamental to a balanced biological education, yet practical demonstrations are rarely considered. In this paper we describe a bacterial liquid microcosm which can be used to demonstrate aspects... more

Understanding evolutionary mechanisms is fundamental to a balanced biological education, yet practical demonstrations are rarely considered. In this paper we describe a bacterial liquid microcosm which can be used to demonstrate aspects of evolution, namely adaptive radiation, niche colonisation and competitive fitness. In microcosms inoculated with Pseudomonas fluorescens SBW25, evolved mutants such as the Wrinkly Spreader (WS) rapidly arise to form biofilms covering the air–liquid (A–L) interface. WS are readily isolated due to a distinctive colony morphology and reach 30% of the population within five days. When re‐inoculated into static microcosms, WS preferentially colonises the A–L interface by producing a biofilm, demonstrating a niche preference distinct from the ancestral SBW25 which grows throughout the liquid column. This ability provides the WS with a 2.5× competitive fitness advantage over the non‐biofilm forming ancestral SBW25. However, WS and SBW25 have similar fitness in shaken microcosms where biofilms cannot form. These practical demonstrations of WS evolution, suitable for secondary or tertiary‐level classes, can be linked with a literature‐based review of the underlying molecular biology of the WS phenotype to provide a true exemplar of the modern evolutionary synthesis, the current paradigm in evolutionary biology.

Ecological specialisation concerns all species and underlies many major ecological and evolutionary patterns. Yet its status as a unifying concept is not always appreciated because of its similarity to concepts of the niche, the many... more

Ecological specialisation concerns all species and underlies many major ecological and evolutionary patterns.
Yet its status as a unifying concept is not always appreciated because of its similarity to concepts of the niche,
the many levels of biological phenomena to which it applies, and the complexity of the mechanisms influencing
it. The evolution of specialisation requires the coupling of constraints on adaptive evolution with covariation
of genotype and environmental performance. This covariation itself depends upon organismal properties
such as dispersal behaviour and life history and complexity in the environment stemming from factors such
as species interactions and spatio-temporal heterogeneity in resources. Here, we develop a view on
specialisation that integrates across the range of biological phenomena with the goal of developing a more
predictive conceptual framework that specifically accounts for the importance of biotic complexity and
coevolutionary events.

Political parties advocating transhumanist ideas have recently sprung up in a great number of countries, supported by rapid technological and scientific progress. This article examines whether any of the various frameworks of niche party... more

Political parties advocating transhumanist ideas have recently sprung up in a great number of countries, supported by rapid technological and scientific progress. This article examines whether any of the various frameworks of niche party theory can adequately describe transhumanist parties. It is discussed how the nicheness of transhumanist parties can be conceptualized. After determining the common set of issues that ideologically diverse transhumanist political organizations accentuate, this article conducts a qualitative analysis to justify the "proto-nicheness" of transhumanist parties within the spatial and salience theories. Two new accounts will be put forward based on Bischof 's consumer market analogy and Hughes's three-dimensional conceptualization of contemporary politics.

Stable carbon isotope analysis of fossil tooth enamel carbonate, and oxygen isotope analysis of bone or enamel phosphate, are established tools for palaeodietary and palaeoclimatic reconstruction, respectively. 13 C / 12 C ratios provide... more

Stable carbon isotope analysis of fossil tooth enamel carbonate, and oxygen isotope analysis of bone or enamel phosphate, are established tools for palaeodietary and palaeoclimatic reconstruction, respectively. 13 C / 12 C ratios provide evidence of an animal’s diet and phosphate-based 18 O / 16 O values are used to establish palaeotemperature proxies. Recent studies of fossil enamel suggest that biogenic 18 O / 16 O signals are also retained in the carbonate compartment, despite assumptions that 18 O / 16 O ratios from apatite carbonate are highly susceptible to exchange during fossilization. Here, we re-examine existing enamel carbonate 18 O / 16 O data from the rich fossil assemblages of Swartkrans and Equus Cave. We find patterns that can be interpreted in terms of drinking behaviour, diet, and physiology. In general, herbivores that drink little are more enriched than those that drink frequently, while carnivores are depleted compared with herbivores. Thus, we can increase our ...

Niche construction and empowerment through sociopolitical work. A metaanalysis of six lowcarbon technology cases Article (Accepted Version) http://sro.sussex.ac.uk Raven, Rob, Kern, Florian, Verhees, Bram and Smith, Adrian (2016) Niche... more

Niche construction and empowerment through sociopolitical work. A metaanalysis of six lowcarbon technology cases Article (Accepted Version) http://sro.sussex.ac.uk Raven, Rob, Kern, Florian, Verhees, Bram and Smith, Adrian (2016) Niche construction and empowerment through socio-political work. A meta-analysis of six low-carbon technology cases.

Although there is an increase in research into how narrative identity interrelates with embodiment, the mechanisms underlying this interplay are hardly addressed. In this paper, I target this hiatus in the literature by proposing two... more

Although there is an increase in research into how narrative identity interrelates with embodiment, the mechanisms underlying this interplay are hardly addressed. In this paper, I target this hiatus in the literature by proposing two mechanisms that can help to (non-exhaustively) elucidate the dynamic interplay of narrative identity and embodiment. I start by briefly sketching the debate so far and then go on to argue that the way narrative self-understanding affects our embodiment can be understood on the model of narrative self-programming. After that I turn to the other side of the interaction. Drawing on research in ecological psychology and phenomenology, I show how embodiment affects our narrative self-understanding through the way in which we engage with affordances in our narrative background. After that I highlight the dynamic and recursive character of this interplay. I end with some conclusions and unresolved issues.

This paper argues that evolutionary thinking and modeling can contribute to the emerging research on sustainability transitions and their management. Evolutionary theory provides a range of concepts and mechanisms that are useful in... more

This paper argues that evolutionary thinking and modeling can contribute to the emerging research on sustainability transitions and their management. Evolutionary theory provides a range of concepts and mechanisms that are useful in making existing theorizing about transitions more precise and complete. In particular, we will discuss how the multi-level, multi-phase, co-evolutionary, and social learning dynamics underlying transitions can be addressed in evolutionary models. In addition, evolutionary theorizing offers suggestions for extending current theoretical frameworks of transitions. Group selection provides a good example. We review the small set of formal evolutionary models of sustainability transitions, and show that existing formal evolutionary models of technological, social and institutional change can provide useful inputs to transition research and management.

1Studies seeking to explain local patterns of diversity have typically relied on niche explanations, reflected in correlations with local environmental conditions, or neutral theory, invoking dispersal processes and speciation.2We used... more

1Studies seeking to explain local patterns of diversity have typically relied on niche explanations, reflected in correlations with local environmental conditions, or neutral theory, invoking dispersal processes and speciation.2We used macroinvertebrate community data from 10 streams that varied independently in local ecological conditions and spatial proximity. Neutral theory predicts that similarity in communities will be negatively associated with distance between sites, while niche theory suggests that community similarity will be positively associated with similarity in local ecological conditions.3Similarity in total invertebrate, grazer and predator assemblages showed negative relationships with distance and, for grazers and predators, positive relationships with local ecological conditions. However, the best model predicting community similarity in all three cases included aspects of both local ecological conditions and distance between sites.4When assemblages were analysed according to dispersal ability, high-dispersal species were shown to be freely accessing all sites and community similarity was not well predicted by either local ecology or spatial separation. Assemblages of species with low and moderate dispersal ability were best predicted by combined models, including distance between sites and local ecological factors.5The results suggest that the perceived dichotomy between neutral and local environmental processes in determining local patterns of diversity may not be useful. Neutral and niche processes structured these communities differentially depending on trophic level and species traits.6We emphasize the potential for both dispersal processes and local environmental conditions to explain local patterns of diversity.Studies seeking to explain local patterns of diversity have typically relied on niche explanations, reflected in correlations with local environmental conditions, or neutral theory, invoking dispersal processes and speciation.We used macroinvertebrate community data from 10 streams that varied independently in local ecological conditions and spatial proximity. Neutral theory predicts that similarity in communities will be negatively associated with distance between sites, while niche theory suggests that community similarity will be positively associated with similarity in local ecological conditions.Similarity in total invertebrate, grazer and predator assemblages showed negative relationships with distance and, for grazers and predators, positive relationships with local ecological conditions. However, the best model predicting community similarity in all three cases included aspects of both local ecological conditions and distance between sites.When assemblages were analysed according to dispersal ability, high-dispersal species were shown to be freely accessing all sites and community similarity was not well predicted by either local ecology or spatial separation. Assemblages of species with low and moderate dispersal ability were best predicted by combined models, including distance between sites and local ecological factors.The results suggest that the perceived dichotomy between neutral and local environmental processes in determining local patterns of diversity may not be useful. Neutral and niche processes structured these communities differentially depending on trophic level and species traits.We emphasize the potential for both dispersal processes and local environmental conditions to explain local patterns of diversity.

We derived physiological models that accurately predicted extinctions of Mexican and other lizards. Clusella-Trullas and Chown argue that global forecasts are unreliable without incorporating variance in microenvironmental temperatures, T... more

We derived physiological models that accurately predicted extinctions of Mexican and other lizards. Clusella-Trullas and Chown argue that global forecasts are unreliable without incorporating variance in microenvironmental temperatures, T e . Here, we show that T e variance is small relative to T e increases from climate warming. Thus, extinction forecasts are reliable ( R ¯ 2 = 0.72 ) even without T e variance data.

This is the first long-term, simultaneous, comparative study of three bamboo lemur species (Hapalemur griseus, H. aureus, and H. simus) at a site in southeasterncentral Madagascar where they occur in sympatry. At Talatakely, Ranomafana... more

This is the first long-term, simultaneous, comparative study of three bamboo lemur species (Hapalemur griseus, H. aureus, and H. simus) at a site in southeasterncentral Madagascar where they occur in sympatry. At Talatakely, Ranomafana National Park, the three Hapalemur spp. share overlapping home ranges. Hapalemur griseus has flexible group sizes, varying from three to nine individuals (n = 6). The home range of Hapalemur griseus averages 15 ha (n = 2). Hapalemur aureus forms family groups of <4 individuals (n = 3); they have a home range on average of 26 ha (n = 2). The single group of Hapalemur simus is composed of one or three adult males, two adult females, and their offspring; they occupy a home range of 62 ha. The three species of Hapalemur are year-round bamboo specialists: >88% of their diets consist of bamboo and grass in the Family Poaceae. Contrary to earlier findings, all three Hapalemur spp. consume the cynogenic parts-young leaf bases, young pseudopetioles, and young shoots-of the giant bamboo, Cathariostachys madagascariensis. They rely heavily on this plant, which comprises 72-95% of their diets. Hapalemur griseus and H. aureus consume similar proportions of bamboo vs. nonbamboo plants, though they differ in the species of bamboo they prefer. Hapalemur simus has the most distinct diet of the three bamboo lemurs. They exploit the young shoots of Cathariostachys madagascariensis during the austral summer rainy season, between November and April. From June to November, Hapalemur simus shifts its diet to eating the mature culm pith of Cathariostachys madagascariensis,-the proportion of pith represented in their diet reaches a maximum of 89% in October. Seasonal availability offood resources, feeding competition, and factors related to body size may provide Tan clues to the understanding of diet selection among the three sympatric Hapalemur spp.

Previous studies carried out in the DonÄ ana National Park reported that red foxes (Vulpes vulpes) were killed by Iberian lynxes (Lynx pardinus), whereas similar-sized Eurasian badgers (Meles meles) were not. Therefore, we predicted that... more

Previous studies carried out in the DonÄ ana National Park reported that red foxes (Vulpes vulpes) were killed by Iberian lynxes (Lynx pardinus), whereas similar-sized Eurasian badgers (Meles meles) were not. Therefore, we predicted that fox would avoid lynx predation risk by niche segregation whereas we did not expect such a segregation between badger and lynx. As an approach for evaluating our predictions, we compared their diet, activity patterns, and habitat use in an area of DonÄ ana where the three carnivores are sympatric. Lynxes preyed almost uniquely on European rabbits (Oryctolagus cuniculus), and though badgers and foxes were omnivorous, rabbits also were a major prey, resulting in high overlaps throughout the year. However, badgers preyed largely on small rabbits, whereas lynxes and foxes preyed mainly on medium-sized rabbits. There were also interspeci®c dierences in activity patterns. Maximum levels of activity among lynxes were during sunrise and dusk (49±67%). Foxes were most active during dusk and night (34±67%), and badgers were mainly nocturnal (53±87%). Though there were seasonal dierences in the amount of activity of each species, speci®c activity patterns changed little throughout the year. There was a strong dierence in annual habitat use by the three species (P < 0.0001). Lynxes used mainly the Mediterranean scrubland during both the active (P MAX ) and the resting (P MIN ) periods. During P MIN , foxes used the Mediterranean scrubland intensively (40% of locations on average), but during P MAX , they used the pastureland much more intensively despite this habitat being poorer in their main prey (rabbits). As a consequence, foxes and lynxes exhibited segregation in their habitat use during the active period. Badgers also used the Mediterranean scrubland intensively, especially during P MIN . There were no seasonal dierences in habitat use for lynx and fox, but there was for badgers (P < 0.015). Within the study area, the three species selected habitat suggesting they were sensitive to factors such as vegetation and prey abundance. However, in general, carnivore habitat use did not correlate with rabbit abundance. We propose that foxes avoided lynxes by using, during activity, habitats not frequented by lynxes, and that a low predation risk associated with the distinctive foraging mode of badgers may facilitate its coexistence with other carnivores.

Public accounting in the United States is a profession not only because it is defined as a profession by statute, but because it also fulfills a significant number of sociological criteria to be accepted as a profession. The recent... more

Public accounting in the United States is a profession not only because it is defined as a profession by statute, but because it also fulfills a significant number of sociological criteria to be accepted as a profession. The recent increase in the demand for ...

The European nightjar is one of the most endangered bird species in Switzerland. As its ecology in the country is poorly understood, we collected data on resource exploitation in the upper Rhoà ne valley (Alps). The diet of two adult... more

The European nightjar is one of the most endangered bird species in Switzerland. As its ecology in the country is poorly understood, we collected data on resource exploitation in the upper Rhoà ne valley (Alps). The diet of two adult birds and one nestling consisted primarily of moths (81 and 93% of biomass), which were also the most abundant prey sampled at the study site. Three radiotracked nightjars selectively exploited oak scrubland compared to vineyards and pine forests; vineyard monocultures harbour presumably insucient moth populations, whereas dense pine stands probably do not provide the¯ying and foraging requirements of nightjars. The survival of nightjars in Valais probably depends both on the existence of sucient populations of moths and on the availability of semi-open natural habitats, such as oak scrubland, which seem to oer the best suitable foraging and nesting places. #

This study examined species richness and relative abundance of eusocial Apidae in an insular region of rain-forest, southeastern Brazil. Sampling took place during one year, using an standardized method with entomological net, at sites of... more

This study examined species richness and relative abundance of eusocial Apidae in an insular region of rain-forest, southeastern Brazil. Sampling took place during one year, using an standardized method with entomological net, at sites of secondary growth habitats surrounded by Atlantic rain-forest. Thirteen species of eusocial Apidae were netted at flowers, over 80% of the captured individuals were meliponine species, although the presence of Apis mellifera, commonly dominant in Brazilian habitats. Foraging activity of these bee species were essentially non-seasonal, apparently affected by high humidity. The patterns in abundance and species richness observed in Ilha Grande differed with other studies conducted at tropical islands, which were characterized by the poverty of meliponine species.