Horizontal Diversity Research Articles

An Extended Ecosystem Model for Understanding EE2 Indirect Effects on a Freshwater Food Web and its Ecosystem Function Resilience

Freshwater species are highly impacted by human activities and the consequences on ecosystem functioning are still not well understood. In the literature, a multitrophic perspective appears to be key to advance future biodiversity and ecosystem functioning (BEF) research. This paper aims at studying indirect effects of the synthetic hormone 17α-ethinylestradiol (EE2) on a freshwater food web by creating BEF links, through the interpretation of seasonal cycles and multitrophic interactions. An ecosystem model previously developed using experimental data from a unique whole-ecosystem study on EE2 was extended with the addition of Chaoborus, an omnivorous insect. During the experimental study, a collapse of fathead minnow was measured after one year of exposure. The simulation results showed that EE2 indirect effects on other fishes (horizontal diversity) and lower trophic levels (vertical diversity) were connected to multitrophic interactions with a top-down cascade effect. The results also demonstrated that adding an omnivorous, mid-trophic level group such as Chaoborus enhances resilience. Conversely, missing such a species means that the actual resilience of an ecosystem and its functioning cannot be properly simulated. Thus, the extended ecosystem model offers a tool that can help better understand what is happening after environmental perturbations, such as with EE2.

Coprophagous Hydrophilid Beetles (Coleoptera, Hydrophilidae, Sphaeridiinae) Distribution in the Polish Carpathians.

Research on coprophagous beetles of the Hydrophilidae family in the Polish Carpathians was conducted from 2011 to 2013. The beetles were caught using baited traps. The research sites were selected to take into account both the horizontal diversity of habitat conditions and the vertical diversity associated with elevation above sea level. During the study, 9589 coprophagous hydrophilid individuals were collected, representing 17 species and five genera. Two species that were new to Poland were found: Cercyon tatricus and Pachysternum capense. The vertical ranges of the individual species of coprophagous hydrophilid beetles within the Polish Carpathians were determined as well as the elevations above sea level, with the highest and lowest species richness of this group of insects. The capture of Pachysternum capense in the Tatra Mountains may indicate the existence of an unrecognized path of migration of small insects from Southern to Northern Europe. The route and mechanisms of their migration are discussed.

Characteristics of pekarangan in organic settlement and planned settlement along Ciliwung River riparian, Bogor Municipality, Indonesia

Riparian is part of the river that contributes to ecosystem preservation. There are green spaces in riparian that have many functions. One of the greens spaces in riparian is pekarangan. The purpose of this paper is to show the result of analyse characteristics of pekarangan in the organic settlements and planned settlements along the Ciliwung River riparian. The study area consists of three riparian zones in two types of settlements, organic settlements and planned settlements, i.e. the upper part (Kelurahan Katulampa); the middle part (Kelurahan Babakan Pasar and Kelurahan Sempur); and the lower part (Kelurahan Kedunghalang). Characteristics of pekarangan were analysed through the approach of size and zoning of pekarangan; vertical and horizontal diversity of plants; plant biodiversity; and types of pekarangan utilization. The results showed that the orientation of organic settlements tends to turn away from the river, while planned settlements face the river. The organic settlements and planned settlements, both have small pekarangan (<120 m2). The pekarangan productivity average of the Shannon-Wiener index in organic settlements was 3.76, while planned settlements were 4.11. The result of the study of all sites are typology of pekarangan in organic settlement and planned settlement.

Programas doctorales en Chile: una propuesta tipológica para interpretar su diversidad

Chile has experienced an accelerated development of doctoral programs. In recent years, the offer has doubled, and the variety of options has significantly expanded with the creation of programs in new areas of knowledge, in different territorial contexts, of an interdisciplinary nature, organized collaboratively among universities. The study seeks to describe and understand the diversity of this offer with the aim of enriching quality improvement initiatives for the programs. Through a cluster analysis, a typology of doctoral programs was constructed based on nine variables that account for four dimensions: inputs, processes, outputs and outcomes.The typology describes and reveals the horizontal diversity within the system, differing from the logic of other tools, such as rankings. The results show an offer organized around five types of programs: strong, consolidated, emerging, developing and weak. The diversity of the system has an ambivalent character: on the one hand, the development of programs in new areas of knowledge, in different territorial contexts and with new characteristics; on the other, the vast differences between the types of programs show that the system does not currently guarantee equivalent quality levels for doctoral students.

Horizontal diversity in test generation for high fault coverage

Determination of the most appropriate test set is critical for high fault coverage in testing of digital integrated circuits. Among black-box approaches, random testing is popular due to its simplicity and cost effectiveness. An extension to random testing is antirandom that improves fault detection by maximizing the distance of every subsequent test pattern from the set of previously applied test patterns. Antirandom testing uses total Hamming distance and total cartesian distance as distance metrics to maximize diversity in the testing sequence. However, the algorithm for the antirandom test set generation has two major issues. Firstly, there is no selection criteria defined when more than one test pattern candidates have the same maximum total Hamming distance and total cartesian distance. Secondly, determination of total Hamming distance and total Cartesian distance is computational intensive as it is a summation of individual Hamming distances and cartesian distances with all the previously selected test patterns. In this paper, two-dimensional Hamming distance is proposed to address the first issue. A novel concept of horizontal Hamming distance is introduced, which acts as a third criterion for test pattern selection. Fault simulations on ISCAS'85 and ISCAS'89 benchmark circuits have shown that employing horizontal Hamming distance improves the effectiveness of pure antirandom in terms of fault coverage. Additionally, an alternative method for total Hamming distance calculations is proposed to reduce the computational intensity. The proposed method avoids summation of individual Hamming distances by keeping track of number of 0s and 1s applied at each inputs. As a result, up to 90 % of the computations are reduced.

Using food network unfolding to evaluate food-web complexity in terms of biodiversity: theory and applications.

Food-web complexity often hinders disentangling functionally relevant aspects of food-web structure and its relationships to biodiversity. Here, we present a theoretical framework to evaluate food-web complexity in terms of biodiversity. Food network unfolding is a theoretical method to transform a complex food web into a linear food chain based on ecosystem processes. Based on this method, we can define three biodiversity indices, horizontal diversity (DH ), vertical diversity (DV ) and range diversity (DR ), which are associated with the species diversity within each trophic level, diversity of trophic levels, and diversity in resource use, respectively. These indices are related to Shannon's diversity index (H'), where H'=DH +DV -DR . Application of the framework to three riverine macroinvertebrate communities revealed that D indices, calculated from biomass and stable isotope features, captured well the anthropogenic, seasonal, or other within-site changes in food-web structures that could not be captured with H' alone.

Reconceptualizing Autism: An Alternative Paradigm for Social Work Practice

ABSTRACTAutism is a complex, often misunderstood condition. More than a neurological disorder, autism can also be viewed as a different cognitive style or an alternative way of perceiving and reacting to the world. As more individuals on the autism spectrum are making themselves known, social workers must be open to using new paradigms to meet the needs of this unique population. This article explores how horizontal diversity and neurodiversity can be used to expand the ways social workers conceptualize autism and, consequently, how they work with persons on the autism spectrum and their families.

Is being connected to leaders always beneficial? Instrumental interaction and the development of social capital within organisational networks

ABSTRACTIndividuals not only have a natural tendency to interact with those who are demographically similar, but also have instrumental motives to contact diverse others and those of a higher status. This study investigates two kinds of instrumental interaction – horizontal diversity (the tendency to socialise with diverse others) and upper reachability (the tendency to socialise with high-status leaders) – in the development of social capital within organisations. The empirical results suggest that horizontal diversity predicts higher network centrality, but upper reachability has an inverted U-shaped effect. It is theoretically postulated that the mechanism by which instrumental interaction creates social capital. The results also suggest that the effect of upper reachability within organisational networks is much more complex than in general social networks, due to higher interdependence and competitiveness.

Diversity and Diversification of Higher Education: Trends, Challenges and Policies

Most current discussions of diversity within higher education systems focus on comparing and contrasting universities located at different positions in the vertical rankings hierarchy. This paper innovates by identifying trends and patterns in horizontal diversification—i. e., diversity of types of study programs, educational concepts, and specializations—and ultimately reaches the conclusion that the current frenzy over rankings is causing quality to be unevenly distributed throughout higher education systems and undermining the concept of “the wisdom of the many.” It begins by distinguishing between the various types of diversity. It then describes various educational reforms and attempts to engineer horizontal diversity across Europe. A discussion follows about the origins of ranking systems and how they took root and gained currency in Europe, where informal differences between universities had previously been seen as trivial and secondary to formal differences, and the possible damaging implications such rankings might have for the quality of education throughout the entire world. Higher education policymakers, the paper concludes, must deliberately focus on bolstering the quality of all educational institutions, not just those with the highest rankings.

Management approaches of conservation areas: Differences in woody vegetation structure in a private and a national reserve

Management approaches taken in protected areas will affect their ability and effectiveness to conserve biodiversity. MalaMala (a concession within Sabi Sand Wildtuin, a private game reserve), and an adjacent area in the Kruger National Park (Kruger, statutory protected area) in South Africa provide a comparison of different types of conservation management. We measured three-dimensional woody vegetation structure, as an integral component of biodiversity, across 6200ha in the two reserves using a LiDAR (Light-Detection-and-Ranging) sensor. We compared how different management approaches in the two reserves affected woody structural diversity. Vertical canopy diversity was measured using: i) percent cover of woody vegetation extracted from LiDAR canopy height models, ii) a volumetric pixel (voxel) approach to extract 3D vertical canopy-height profiles; and iii) horizontal diversity using landscape metrics. MalaMala had higher vegetation density than Kruger in the <3m (2.5 times) and >6m (2.7 times) height classes. This vegetation was in the form of larger, more cohesive patches as a result of the legacy of previous land-use (cattle ranching) and current management practices (bush clearing) and the recent increase in megaherbivores. Length of exposure to, and recent higher densities of, megaherbivores (particularly elephants) has altered the density of tall trees in the two reserves, thus affecting structural heterogeneity and associated habitat options for small-bodied vertebrates. These differences in vegetation structure are exacerbated by current management practices (e.g. bush-clearing and fire regime), with potential implications for faunal biodiversity conservation across a wide range of scales.

FORMULATION OF SUSTAINABLE AGRO FORESTRY MODELS FOR NORTH CENTRAL DRY ZONE OF SRI LANKA

Increase of human population and clearing of forests for their requirements has been alocal as well as global environmental crisis. In Sri Lanka, forest cover has dwindled at analarming rate from 70% in 1990 to 22% as of present. Deforestation and degradation ofland due to many reasons including poverty related land management practices such asshifting cultivation and forest encroachments, conversion of forest estate to other moreeconomically profitable land uses are some of the reasons for the loss of forest. agroforestryhas been identified all over the world as an appropriate alternative which providessustainabilityAccording to the Forestry Sector master Plan (1995) the necessity of utilizing the sparsely·used scrub lands for agroforestry ventures to improve the tree cover and socio-economicstatus of the people has been identified. Forest Department too in its Participatory ForestryProject has ventured into establishment of farmers woodlots with the active participation ofcommunities and this programme is wide spread in many parts of the country especially inthe dry zone. However, the composition of these farmers woodlots still not complete toincorporate diversity and sustainability. Therefore, the objective of this present study is toformulate sustainable tree-crop models for a wide range of land classes in the north centraldry zone of Sri LankaIpalogama divisional Secretariat in Anuradhapura District was identified for the study.Field studies were done in handsomely selected 3 traditional tank based villages namelySangattewa, Puliyankulama and Dampeleassagama . Information was gathered through aquestionnaire survey, field visits and personnel interviews with villagers. Randomelyselected 44 households or 14.8% of the total households in the 3 villages were subjected tothe survey. The species composition and vertical and horizontal diversity, lightrequirements, multiple uses, financial returns/ha, prevalence of local/indigenous treespecies and farmer's choice were taken into consideration in the formulation of theagroforestry models for the various land classes sampled egoAlluvial plains, middle slopesand upper slopes etc.

Trophic complexity enhances ecosystem functioning in an aquatic detritus‐based model system

1. Understanding the functional significance of species interactions in ecosystems has become a major challenge as biodiversity declines rapidly worldwide. Ecosystem consequences arising from the loss of diversity either within trophic levels (horizontal diversity) or across trophic levels (vertical diversity) are well documented. However, simultaneous losses of species at different trophic levels may also result in interactive effects, with potentially complex outcomes for ecosystem functioning. 2. Because of logistical constraints, the outcomes of such interactions have been difficult to assess in experiments involving large metazoan species. Here, we take advantage of a detritus-based model system to experimentally assess the consequences of biodiversity change within both horizontal and vertical food-web components on leaf-litter decomposition, a fundamental process in a wide range of ecosystems. 3. Our concurrent manipulation of fungal decomposer diversity (0, 1 or 5 species), detritivore diversity (0, 1 or 3 species), and the presence of predatory fish scent showed that trophic complexity is key to eliciting diversity effects on ecosystem functioning. Specifically, although fungi and detritivores tended to promote decomposition individually, rates were highest in the most complete community where all trophic levels were represented at the highest possible species richness. In part, the effects were trait-mediated, reflected in the contrasting foraging responses of the detritivore species to predator scent. 4. Our results thus highlight the importance of interactive effects of simultaneous species loss within multiple trophic levels on ecosystem functioning. If a common phenomenon, this outcome suggests that functional ecosystem impairment resulting from widespread biodiversity loss could be more severe than inferred from previous experiments confined to varying diversity within single trophic levels.

Disturbing the pedagogical status quo: LLN and vocational teachers working together

When language, literacy and numeracy (LLN) teachers work together with vocational teachers as a team, not only do students improve their course outcomes in terms of completions and employment, but the pedagogical practices of both teachers can change and improve. In this article, we begin to explore some of the issues and provide examples of pedagogical changes, linking them with research on interdisciplinary teacher teams in other education sectors that draw on activity theory, and higher education studies of “academic literacies”. This article draws on a recent national study of the integration of LLN in the delivery of vocational education and training (VET) courses in Australia in which interviews with over 50 VET teachers and managers provided insights into the pedagogies that emerge when LLN teachers and vocational teachers work as a team. Particularly significant is the relative status of the teachers working together and the cultural and historical practices that enforce or challenge this. Pedagogical changes are encouraged in situations where teachers have equal status and their respective specialist disciplinary expertise is in a relationship of horizontal diversity to each other.

Spatial heterogeneity and the distribution of bromeliad pollinators in the Atlantic Forest

Interactions between plants and their pollinators are influenced by environmental heterogeneity, resulting in small-scale variations in interactions. This may influence pollinator co-existence and plant reproductive success. This study, conducted at the Estação Biológica de Santa Lúcia (EBSL), a remnant of the Atlantic Forest in southeastern Brazil, investigated the effect of small-scale spatial variations on the interactions between bromeliads and their pollinators. Overall, hummingbirds pollinated 19 of 23 bromeliad species, of which 11 were also pollinated by bees and/or butterflies. However, spatial heterogeneity unrelated to the spatial location of plots or bromeliad species abundance influenced the presence of pollinators. Hummingbirds were the most ubiquitous pollinators at the high-elevation transect, with insect participation clearly declining as transect elevation increased. In the redundancy analysis, the presence of the hummingbird species Phaethornis eurynome, Phaethornis squalidus, Ramphodon naevius, and Thalurania glaucopis, and the butterfly species Heliconius erato and Heliconius nattereri in each plot was correlated with environmental factors such as bromeliad and tree abundance, and was also correlated with horizontal diversity. Since plant-pollinator interactions varied within the environmental mosaics at the study site, this small-scale environmental heterogeneity may relax competition among pollinators, and may explain the high diversity of bromeliads and pollinators generally found in the Atlantic Forest.

Spatial distribution of rotifers (Rotifera) in monospecies beds of invasive Vallisneria spiralis L. in heated lakes

Abstract Species abundance and richness of rotifer communities occupying monospecies beds of Vallisneria was studied in Lake Licheńskie included in the open cooling system of heat and power stations. Differences were found in rotifer numbers, species composition and diversity between sampling points within the same location and between the locations. Factors that seem to be responsible for the high diversity of rotifer communities inhabiting Vallisneria beds are: large-scale horizontal diversity (between macrophyte patches), small-scale horizontal diversity (within patches) and the high vulnerability of Vallisneria epiphyton to disturbances caused by wave action.

Comparative study of gas accumulations in the Permian Changxing reefs and Triassic Feixianguan oolitic reservoirs between Longgang and Luojiazhai-Puguang in the Sichuan Basin

Reef and oolitic gas reservoirs in the Permian Changxing and Triassic Feixianguan formations have been discovered in both the Luojiazhai-Puguang and Longgang areas of the Sichuan Basin, but the accumulation scale, abundance and distribution patterns differ greatly. In fact, the two areas have more differences than they have similarities. Similarities include: (1) the lithology, properties and types of porosity of the reef and oolitic reservoirs are primarily consistent in the two areas; (2) well-developed regional caprocks that seal the fluid system; and (3) accumulation process histories, with liquid hydrocarbon charging at an early stage, cracking into gas at a high to over-mature stage, adjustment of gas reservoirs at an uplifting stage, and final reservoir generation at a late stage. Differences include: (1) gas accumulations in the Luojiazhai-Puguang area that are dominated by oil-type cracked gas, with multiple and sufficient gas sources, contrasting with gas accumulations in the Longgang area that are dominated by coal-sourced gas with insufficient gas sources; (2) heterogeneity and horizontal diversity of reservoirs in the Longgang area that are stronger than in the Luojiazhai-Puguang area; and (3) the development of deep and large faults in the Luojiazhai-Puguang area that link source, reservoir and migration pathways, contrasting with poorly developed faults in Longgang area, where laterally variable fractures are the major migration pathway. Because of these differences, abundant large-scale structurally-controlled gas accumulations are developed in the Luojiazhai-Puguang area, whereas lithology plays a more important role in gas accumulation in the Longgang area where accumulations are smaller-scale and have lower gas-bearing abundance. We suggest that future exploration for reef and oolitic gas accumulations should be strengthened in NE Sichuan and NW Sichuan Jiulongshan. In particular, the transitional zone between Longgang and Kaijiang-Liangping Bay has the best potential for new discoveries.

Curriculum as Colonizer: (Asian) American Education in the Current U.S. Context

Background/Context The United States is currently undergoing a period of unprecedented immigration, with the majority of new arrivals coming from Asia and Latin America, not Europe. Asian Americans and Pacific Islanders (APIs) represent the fastest growing racial group in the United States, and schools are again being asked to socialize newcomer students, many of whom are APIs. Yet, even as the United States becomes more racially diverse, the national mindset regarding immigrants and immigration ranges from ambivalent to increasingly (and currently) hostile, and is often contradictory. “American” typically is imagined as “White,” and perceptions of APIs and people of color as “other” remain cemented in our collective psyche. It is this sociohistorical-political context that frames the education and socialization of Asian American citizens, immigrants, and their children. Objective/Focus As APIs are absorbed into the fabric of society, how will they define themselves? How will they be defined? This article begins by deconstructing the social category Asian and Pacific Islander in order to reveal the immense diversity contained under this label. The discussion illuminates both the horizontal diversity of APIs—differences between ethnic groups, and vertical diversity—differences within ethnic groups, to underscore the insufficiency of the API label. Against the diverse backdrop that APIs truly (re)present, (Asian) American education framed by three curricular contexts in the United States—the major reforms of the 2001 No Child Left Behind Act, culturally relevant pedagogy, and the “model minority” mythology—is theorized using postcolonial theory as an analytic lens. The article concludes with thoughts on how APIs can resist domination and what might be sites of resistance in schools or society. Research Design This is an analytic essay that examines both historical and contemporary educational and policy contexts. Conclusions/Recommendations Curriculum, defined not simply as subject matter content and instructional procedures, but as a tool of acculturation and a depository of (U.S.) national and cultural values, has the power to emancipate or colonize. Each of the three curricular contexts in the United States—the major reforms of the No Child Left Behind Act, culturally relevant pedagogy, and the “model minority” mythology—exemplify the role Curriculum plays in defining, silencing, and/or marginalizing APIs. Imagined sites of resistance against Curriculum as colonizer include this very page, where one voice deliberately pushes back against the obfuscation of fixed realities layered onto people of Asian descent in the United States, the reexamination and revision(ing) of teacher preparation curricula, and the larger policy arena.

Reducing horizontal and vertical diversity in a foodweb triggers extinctions and impacts functions

Species loss can result in secondary extinctions and changes in ecosystem functions at distant trophic levels. Such effects of species loss are predicted to be affected by both the number of species lost within a trophic level (horizontal diversity) and the number of trophic levels lost (vertical diversity). We experimentally manipulated horizontal and vertical diversity within an aquatic insect community, and examined responses throughout the food web. Horizontal and vertical diversity both impacted ciliates: reduction of detritivorous insect diversity resulted in secondary extinctions and decreased density of ciliates, but only when an insect predator was simultaneously absent. Horizontal and vertical diversity differed in their effect on other foodweb processes, including detrital processing, predator growth, and densities of rotifers, flagellates and flatworms. These results caution that foodweb effects of multitrophic species loss may not be reliably predicted from manipulations of just one dimension of diversity.

Funding Diversity: Performance-based Funding Regimes as Drivers of Differentiation in Higher Education Systems

In most countries higher education institutions used to receive large portions of their funding by direct state allocation. For the past couple of decades this trust-based funding regime has been replaced by performance-based regimes. The article rests on the empirical observation that new funding regimes are increasingly becoming a policy instrument that is used to deal with resource allocation in growing higher education systems. It is argued that performance-based funding is used to promote vertical differentiation and functional specialization between institutions while at the same time secure horizontal diversity and pluralism within the system. The sweeping change is orchestrated by governments that are pressed by globalization to provide high-ranking, attractive institutions for hubs of innovation and competitiveness in knowledge-based economies. Advocates can be found among business and competitive universities, whereas reforms cause concern among other academics who perceive a loss of academic freedom and professional status.

The functional role of biodiversity in ecosystems: incorporating trophic complexity

Understanding how biodiversity affects functioning of ecosystems requires integrating diversity within trophic levels (horizontal diversity) and across trophic levels (vertical diversity, including food chain length and omnivory). We review theoretical and experimental progress toward this goal. Generally, experiments show that biomass and resource use increase similarly with horizontal diversity of either producers or consumers. Among prey, higher diversity often increases resistance to predation, due to increased probability of including inedible species and reduced efficiency of specialist predators confronted with diverse prey. Among predators, changing diversity can cascade to affect plant biomass, but the strength and sign of this effect depend on the degree of omnivory and prey behaviour. Horizontal and vertical diversity also interact: adding a trophic level can qualitatively change diversity effects at adjacent levels. Multitrophic interactions produce a richer variety of diversity-functioning relationships than the monotonic changes predicted for single trophic levels. This complexity depends on the degree of consumer dietary generalism, trade-offs between competitive ability and resistance to predation, intraguild predation and openness to migration. Although complementarity and selection effects occur in both animals and plants, few studies have conclusively documented the mechanisms mediating diversity effects. Understanding how biodiversity affects functioning of complex ecosystems will benefit from integrating theory and experiments with simulations and network-based approaches.