Ecological Systems Model Research Articles

Creating Safe Space for Undocumented Students: Building on Politically Unstable Ground

This article presents a case study that examines how undocumented students created a safe space for themselves on their college campus and how that space was ultimately institutionalized by the university. It also considers the politically vulnerable position of undocumented youth in such endeavors. Drawing from Bronfenbrenner's ecological systems model, the analysis provided here examines the micro and macro contexts that facilitate and impede the development of safe space for undocumented students.

ENVIRONMENTAL MANAGEMENT AS A COMPONENT OF AN INTEGRATED MANAGEMENT SYSTEM FOR GAS CONDENSATE AND OIL PROCESSING ENTERPRISES

Розглянуто результати діяльності та етапи впровадження різних заходів екологічної політики підприємства на прикладі Шебелинського відділення з переробки газового конденсату та нафти. Запропоновано структурну схему моделі системи екологічного управління як важливої складової інтегрованої системи управління підприємства з перероблення газового конденсату та нафти на основі залучення наукової літератури, нормативно-правових документів з застосуванням структурно-логічного методу, систематизації та узагальнення та методів змістовного та порівняльного аналізу. Розглянуті особливості впровадження міжнародних екологічних стандартів серії ISO 9000 та ISO 14000 щодо створення інтегровано системи управління. Доведено, розроблення і впровадження на підприємстві з перероблення газового конденсату та нафти інтегрованої системи управління надає деякі переваги, зокрема підвищення загальної конкурентоспроможності продукції та адаптації до ринкових умов, формування екологічної політики, та підходів до ефективного використання ресурсів. Формування інтегрованої системи управління відбувається впродовж чотирьох основних етапів, це планування, впровадження, перевірка та коригування. Невід’ємною складовою процесу формування інтегрованої системи управління є використання у комплексі процесного та системного підходу. Застосування адитивної моделі та моделі одночасного інтегрування дало змогу при поступовому впровадженні створити єдину систему управління на основі вимог різних стандартів та значно зменшити обсяг документації.

Multilocus phylogeny of Gryllus field crickets (Orthoptera: Gryllidae: Gryllinae) utilizing anchored hybrid enrichment.

We present the first comprehensive molecular phylogeny of Gryllus field cricket species found in the United States and Canada, select additional named Gryllus species found in Mexico and the Bahamas, plus the European field cricket G. campestris Linnaeus and the Afro-Eurasian cricket G. bimaculatus De Geer. Acheta, Teleogryllus, and Nigrogryllus were used as outgroups. Anchored hybrid enrichment was used to generate 492,531 base pairs of DNA sequence from 563 loci. RAxML analysis of concatenated sequence data and Astral analysis of gene trees gave broadly congruent results, especially for older branches and overall tree structure. The North American Gryllus are monophyletic with respect to the two Old World taxa; certain sub-groups show rapid recent divergence. This is the first Anchored Hybrid Enrichment study of an insect group done for closely related species within a single genus, and the results illustrate the challenges of reconstructing the evolutionary history of young rapidly diverged taxa when both incomplete lineage sorting and probable hybridization are at play. Because Gryllus field crickets have been used extensively as a model system in evolutionary ecology, behavior, neuro-physiology, speciation, and life-history and life-cycle evolution, these results will help inform, interpret, and guide future research in these areas.

Restoration in the face of changing climate: importance of persistence, priority effects, and species diversity

Grasslands are extensive, surprisingly biodiverse, highly altered by humans, and not as well protected as other biomes. Restoration provides an opportunity to reverse degradation and increase local biodiversity. Here, I review emerging issues that will become increasingly important to the science and practice of restoration ecology. First, the global change dilemma. Restorations typically target species that were dominant before the Industrial Revolution, in effect, looking back in time. However, increasing atmospheric CO2 and methane, temperature, and nutrients, which are already having significant effects, will result in novel conditions that are unlike the past. Biotic introductions have occurred concurrently with climate change, altering the seed bank and propagule pressure from surroundings. Designing seed mixes with high diversity will increase the likelihood that species will be present that respond favorably to changes. Second, more research is needed on persistence as a long‐term measure of stability. What is perhaps most important to restoration is how persistent restorations are on decade to century scales, and restorations are now of sufficient quantity and age to test questions about persistence. Third, the importance of stochastic processes due to priority effects has been supported by recent studies and have challenged the deterministic assembly model. Target species establishment could be improved by changing the order of introduction of species. Finally, grasslands provide many ecosystem services to society, including nutrient capture, food production, carbon storage, tourism and recreation, and nectar and pollen production. Grasslands are important culturally as outdoor science laboratories. For these reasons, I suggest that grasslands provide an excellent model system for restoration ecology.

Phylogenomic data reveal reticulation and incongruence among mitochondrial candidate species in Dusky Salamanders (Desmognathus)

Gene flow between evolutionarily distinct lineages is increasingly recognized as a common occurrence. Such processes distort our ability to diagnose and delimit species, as well as confound attempts to estimate phylogenetic relationships. A conspicuous example is Dusky Salamanders (Desmognathus), a common model-system for ecology, evolution, and behavior. Only 22 species are described, 7 in the last 40 years. However, mitochondrial datasets indicate the presence of up to 45 “candidate species” and multiple paraphyletic taxa presenting a complex history of reticulation. Some authors have even suggested that the search for species boundaries in the group may be in vain. Here, we analyze nuclear and mitochondrial data containing 161 individuals from at least 49 distinct evolutionary lineages that we treat as candidate species. Concatenated and species-tree methods do not estimate fully resolved relationships among these taxa. Comparing topologies and applying methods for estimating phylogenetic networks, we find strong support for numerous instances of hybridization throughout the history of the group. We suggest that these processes may be more common than previously thought across the phylogeography-phylogenetics continuum, and that while the search for species boundaries in Desmognathus may not be in vain, it will be complicated by factors such as crypsis, parallelism, and gene-flow.

Monitoring biodiversity in the Anthropocene using remote sensing in species distribution models

In the face of the growing challenges brought about by human activities, effective planning and decision-making in biodiversity and ecosystem conservation, restoration, and sustainable development are urgently needed. Ecological models can play a key role in supporting this need and helping to safeguard the natural assets that underpin human wellbeing and support life on land and below water (United Nations Sustainable Development Goals; SDG 15 & 14). The urgency and complexity of safeguarding forest (SDG 15.2) and mountain ecosystems (SDG 15.4), for example, and halting decline in biodiversity (SDG 15.5) in the Anthropocene requires a re-envisioning of how ecological models can best support the comprehensive assessments of biodiversity and its change that are required for successful action.A key opportunity to advance ecological modeling for both predictive and explanatory purposes arises through a collaboration between ecologists and the Earth observation community, and a close integration of remote sensing and species distribution models. Remote sensing products have the capacity to provide continuous spatiotemporal information about key factors driving the distribution of organisms, therefore improving both the use and accuracy of these models for management and planning.Here we first survey the literature on remote sensing data products available to ecological modelers interested in improving predictions of species range dynamics under global change. We specifically explore the key biophysical processes underlying the distribution of species in the Anthropocene including climate variability, changes in land cover, and disturbances. We then discuss potential synergies between the ecological modeling and remote sensing communities, and highlight opportunities to close the data and conceptual gaps that currently impede a more effective application of remote sensing for the monitoring and modeling of ecological systems. Specific attention is given to how potential collaborations between the two communities could lead to new opportunities to report on progress towards global agendas - such as the Agenda 2030 for sustainable development of the United Nations or the Post-2020 Global Biodiversity Framework of the Convention for Biological Diversity, and help guide conservation and management strategies towards sustainability.

Model systems to elucidate minimum requirements for protected areas networks

In conservation biology there have been varying answers to the question of “How much land to protect?” Simulation models using decision-support software such as Marxan show that the answer is sensitive to target type and amount, and issues of scale. We used a novel model system for landscape ecology to test empirically whether the minimum conservation requirements to represent all species at least once are consistent across replicate landscapes, and if not, whether these minimum conservation requirements are linked to biodiversity patterns. Our model system of replicated microcosms could be scaled to larger systems once patterns and mechanisms are better understood. We found that the minimum representation requirements for lichen species along the microlandscapes of tree trunks were remarkably consistent (4–6 planning units) across 24 balsam fir trees in a single stand, as well as for 21 more widely dispersed fir and yellow birch trees. Variation in minimum number of planning units required correlated positively with gamma diversity. Our results demonstrate that model landscapes are useful to determine whether minimum representation requirements are consistent across different landscapes, as well as what factors (life history, diversity patterns, dispersal strategies) affect variation in these conservation requirements. This system holds promise for further investigation into factors that should be considered when developing conservation designs, thus yielding scientifically-defensible requirements that can be applied more broadly.

Genetic structure and biogeographic history of the Bicknell’s Thrush/ Gray-cheeked Thrush species complex

AbstractWe examined species limits, admixture, and genetic structure among populations in the Bicknell’s Thrush (Catharus bicknelli)–Gray-cheeked Thrush (C. minimus) species complex to establish the geographic and temporal context of speciation in this group, which is a model system in ecology and a high conservation priority. We obtained mitochondrial ND2 sequences from 186 Bicknell’s Thrushes, 77 Gray-cheeked Thrushes, and 55 individuals of their closest relative, the Veery (C. fuscescens), and genotyped a subset of individuals (n = 72) at 5,633 anonymous single nucleotide polymorphic (SNP) loci. Between-species sequence divergence was an order of magnitude greater than divergence within each species, divergence was dated to the late Pleistocene (420 kbp) based on Bayesian coalescence estimation, and a coalescent model (IMa) revealed almost no gene flow between species based on ND2. SNP data were consistent with mitochondrial results and revealed low levels of admixture among species (3 of 37 Bicknell’s Thrushes, no Gray-cheeked Thrushes, and no Veeries were >2% admixed). Species distribution models projected to the Last Glacial Maximum suggest that Bicknell’s Thrush and Gray-cheeked Thrush resided in primarily allopatric refugia in the late Pleistocene, consistent with the genetic data that support reproductive isolation over an extended period of time. Our genetic data suggest that both species underwent demographic expansions, possibly as they expanded out of Pleistocene refugia into their current ranges. We conclude that Bicknell’s Thrush and Gray-cheeked Thrush are 2 distinct species-level lineages despite low levels of Gray-cheeked Thrush introgression in Bicknell’s Thrushes, and divergence has been maintained by a long history of allopatry in subtly different habitats. Their unique phylogeography among boreal forest birds indicates that either cryptic species breaks in eastern North America are still undiscovered, or another factor, such as divergent natural selection, high migratory connectivity, or interspecific competition, played a role in their divergence.

Understanding interactions between urban development policies and GHG emissions: A case study in Stockholm\xa0Region

Human-induced urban growth and sprawl have implications for greenhouse gas (GHG) emissions that may not be included in conventional GHG accounting methods. Improved understanding of this issue requires use of interactive, spatial-explicit social–ecological systems modeling. This paper develops a comprehensive approach to modeling GHG emissions from urban developments, considering Stockholm County, Sweden as a case study. GHG projections to 2040 with a social–ecological system model yield overall greater emissions than simple extrapolations in official climate action planning. The most pronounced difference in emissions (39% higher) from energy use single-residence buildings resulting from urban sprawl. And this difference is not accounted for in the simple extrapolations. Scenario results indicate that a zoning policy, restricting urban development in certain areas, can mitigate 72% of the total emission effects of the model-projected urban sprawl. The study outcomes include a decision support interface for communicating results and policy implications with policymakers.

Revealing Complex Ecological Dynamics via Symbolic Regression.

Understanding the dynamics of complex ecosystems is a necessary step to maintain and control them. Yet, reverse-engineering ecological dynamics remains challenging largely due to the very broad class of dynamics that ecosystems may take. Here, this challenge is tackled through symbolic regression, a machine learning method that automatically reverse-engineers both the model structure and parameters from temporal data. How combining symbolic regression with a "dictionary" of possible ecological functional responses opens the door to correctly reverse-engineering ecosystem dynamics, even in the case of poorly informative data, is shown. This strategy is validated using both synthetic and experimental data, and it is found that this strategy is promising for the systematic modeling of complex ecological systems.

Thumper the Infinitesimal Rabbit: A Fictionalist Perspective on Some “Unimaginable” Model Systems in Biology

Fictionalists believe that scientific models are about model systems that are imaginary. Michael Weisberg has claimed that fictionalism is indefensible because many scientific models are about model systems that are unimaginable. According to a certain account of imagination, what Weisberg says is plausible. According to another, more defensible account of imagination, it is not. I discuss these issues within the context of an allegedly unimaginable model system in ecology, but the conclusions I draw are more general. I then describe how fictionalism should be recast in order to deal with Weisberg’s critique.

Does chemistry make a difference? Milkweed butterfly sequestered cardenolides as a defense against parasitoid wasps

Plant allelochemicals have important roles in plant defense as well as ecological and co-evolutionary dynamics within tri-trophic systems of plants, herbivores, and natural enemies. Milkweed butterflies represent a model system for chemical ecology because they sequester cardenolides semi-proportionally to the concentration in their host plants, yet little is known about the role of sequestered cardenolides in interactions with invertebrate natural enemies. We experimentally tested the preference and performance of two species of parasitic wasps (Pteromalus cassotis Walker and Pteromalus puparum Linnaeus) on milkweed butterfly pupae (monarchs, Danaus plexippus Linnaeus, and Euploea core Cramer) reared on plants to contain variable concentrations of sequestered cardenolides. We measured host survival and parasitoid reproductive success to determine whether greater concentrations of herbivore-sequestered plant toxins provide a defensive benefit or influence parasitoid success. We found that P. puparum was unable to develop from monarchs, regardless of toxicity. Monarchs containing more cardenolides (those fed Asclepias curassavica) were more likely to survive encounters with P. cassotis than those containing fewer cardenolides (fed Asclepias incarnata), but only because this parasitoid was less likely to attack more toxic monarchs. Once attacked, host toxicity had no effect on the likelihood of monarch survival nor the emergence of parasitoids. Host toxicity affected parasitoid performance in more subtle ways, however, decreasing P. cassotis brood size and survival to adulthood. When attacking cardenolide-free E. core pupae, P. cassotis reproduced successfully, but P. puparum did not, suggesting that milkweed butterflies may employ other defenses against parasitoids, perhaps in addition to cardenolides.

Needle exchange programmes in Visegrad countries: a comparative case study of structural factors in effective service delivery

BackgroundHarm reduction services, despite their proved effectiveness in the prevention of infectious diseases, are still underdeveloped in several European states. The situation in the Visegrad Group countries is especially interesting. Notwithstanding the shared history, culture and political situation in the last decades, there are significant differences in the state of harm reduction between the countries.MethodsThe research applies the ecological systems model to identify the structural barriers and facilitators affecting organisations providing needle exchange services. It uses a comparative multiple case study design with embedded units of analysis complemented by within-case analysis to establish the relationship between the number and scope of identified factors and the performance of needle exchange services. The qualitative data were collected through semi-structured interviews with professionals working in needle exchange services in the Czech Republic, Poland, Slovakia and Hungary. Additionally, relevant documents, reports and online sources were analysed.ResultsA total of 24 themes (structural factors) were identified across 11 categories on 3 levels (mesosystem, exosystem, macrosystem). The list includes themes related to the broader society, politics and policy on state and local level, frameworks and amounts of funding, the situation on the education labour market, and attitudes of local communities, among others. The data shows that in the Czech Republic, many facilitators can be identified. In the three remaining countries, on the contrary, one can observe mostly barriers in NSP services delivery.ConclusionsThe study addresses a highly unexplored topic of the functioning of harm reduction organisations in East-Central Europe. It sheds light on the environment of analysed services, identifying a number of structural factors in effective service delivery in the Czech Republic, Poland, Slovakia and Hungary. The research confirms the significant role of the barriers and facilitators in the services’ performance. It highlights the relationships between various elements of the needle exchange programmes’ environment, suggesting holistic strategies for addressing them. It also provides a potential starting point for further research.

Toward a Developmental Science of Politics.

Toward a Developmental Science of Politics.

What five insects told us about how a native plant copes with real-world problems

What five insects told us about how a native plant copes with real-world problems

Priming and filtering of antiherbivore defences among Nicotiana attenuata plants connected by mycorrhizal networks.

Arbuscular mycorrhizal fungi (AMF) establish symbiotic associations with a majority of terrestrial plants to form underground common mycorrhizal networks (CMNs) that connect neighbouring plants. Because Nicotiana attenuata plants do not respond to herbivory-elicited volatiles from neighbours, we used this ecological model system to evaluate if CMNs function in interplant transmission of herbivory-elicited responses. A mesocosm system was designed to establish and remove CMNs linking N.attenuata plants to examine the herbivory-elicited metabolic and hormone responses in CMNs-connected "receiver" plants after the elicitation of "donor" plants by wounding (W) treated with Manduca sexta larval oral secretions (OS). AMF colonization increased constitutive jasmonate (JA and JA-Ile) levels in N.attenuata roots but did not affect well-characterized JAs-regulated defensive metabolites in systemic leaves. Interestingly, larger JAs bursts, and higher levels of several amino acids and particular sectors of hydroxygeranyllinalool diterpene glycoside metabolism were elevated in the leaves of W+OS-elicited "receivers" with CMN connections with "donors" that had been W+OS-elicited 6hr previously. Our results demonstrate that AMF colonization alone does not enhance systemic defence responses but that sectors of systemic responses in leaves can be primed by CMNs, suggesting that CMNs can transmit and even filter defence signalling among connected plants.

Maltreatment in Youth Sport: A Systemic Issue

The recent, highly publicized cases of maltreatment of athletes have garnered critical attention by the public at large and stakeholders in sport, alike. For many, these cases threaten popular views that sport contributes in important ways to positive youth development. The growing evidence showing that maltreatment occurs to youth sport participants highlights the need for safe, harm-free sport environments as a fundamental prerequisite for positive developments to be reaped. By unpacking the case study of USA Gymnastics and Dr. Larry Nassar’s abuses in this paper, the authors show that for athlete maltreatment to occur and be sustained across so many victims and so many years, more than a perpetrator is needed. The nature of the environment, from the interpersonal level to organizational policies and societal influences, contributes to the occurrence and perpetuation of athlete maltreatment. Using Bronfenbrenner’s ecological-systems model, the authors argue for a systemic approach to preventing and addressing athlete maltreatment. Recommendations are posed for safeguarding youth athletes and fostering the sporting conditions in which positive youth development can occur.

An adapted ecosystem model for inclusive early childhood education: a qualitative cross European study

ABSTRACT Early intervention for children vulnerable to exclusion is currently focused on the child’s effective inclusion in mainstream early childhood education. There is thus a search for developing a shared understanding of what constitutes quality inclusive preschool provision. This was the aim of a qualitative 3-year (2015–17) study of inclusive settings for children from 3 years to compulsory education across European countries, conducted by the European Agency for Special Needs and Inclusive Education. Data consisted of practitioner descriptions of 32 example inclusive preschools from 28 European countries, and more detailed data collected during short visits to eight of the example settings. Qualitative, thematic analysis identified 25 subthemes representing the perceived constituents of inclusive early childhood education provision. These were organised within a framework that intertwined the structure-process-outcome model with the ecological systems model. The resulting adapted ecosystem model for inclusive early childhood education comprises five dimensions: (1) the inclusive education outcomes, (2) processes, and (3) structural factors within the micro environment of the preschool; and the wider (4) inclusive structural factors at community, and (5) at national levels. The framework can be useful for practitioners as well as researchers and policy makers seeking to improve inclusive early childhood education provision.

Teacher’s Support and Student Involvement in Learning Activities on Enhancing Student Academic Achievement

This study aims to identify the level of teachers’ support and the involvement of students in learning activities to improve academic achievement of high school students. Teachers’ support refers to teaching activities in the classroom. Student involvement is seen from the aspect of student learning in the classroom. The conceptual framework of the study combines two theories and a model which are the theory or model of the human ecological system (Bronfenbrenner, 1979), social capital theory (Robert and Putnam, 2000) and aspiration model of the Malaysian Education System in the Malaysia Education Blueprint 2013–2025 (2013). This study is a survey using questionnaire for information. The sample was chosen randomly, involving a total of 200 form four students in Negeri Sembilan. The whole construct is at a high level of reliability of 0.926. This study uses descriptive analysis of mean and standard deviation using Statistical Packages for the Social Sciences (SPSS) Version 24. The results show that teachers’ support and student involvement in classroom learning activities are at moderate level. The implication of the study found that teachers and the school need to increase their efforts, programs and activities in improving student academic achievement.

Embryonic and larval development of the northern pike: An emerging fish model system for evo-devo research.

The northern pike, Esox lucius, is one of the largest temperate freshwater apex predators with a characteristic morphology: an elongated body with pelvic, dorsal, and anal fins located at the rear as a functional feature to sprint predation. However, the typical pike character is its head, which is characterized by a long, flattened snout, a well-armed mouth with numerous teeth, and large eyes characteristic of shallow water visual predators. Although the northern pike is becoming increasingly popular as a model system for ecology and evolutionary research, a detailed staging table has not yet been reported. In this study, we report the first comprehensive staging table for the northern pike, spanning from the one-cell stage to the freely-swimming juvenile stage. In addition to classical embryological descriptions, we use a DAPI staining to distinguish individual cells and embryonic structures during the early development. This dataset, in combination with the genomic and transcriptomic resources already available, serves as a foundation for in-depth mechanistic studies dealing with development using this species.