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The fate of coral reef biodiversity could be predicted from the extant situation and understanding the possible temporal and spatial mechanisms. Among the many hypotheses explaining the biodiversity, the Intermediate Disturbance Hypothesis is the most often tested. It proposed that the frequencies and intensities of disturbance determine the biological species diversity of a habitat; here seasonal recruitment is not considered an important factor. We propose Seasonal Recruitment Hypothesis here with three important characteristics and predictions: there is different assemblages of recruitment after disturbance in different seasons; the following succession is lead by these initial assemblages and thus have different patches for spaces created in different seasons. Mosaic of patches, each with different history, combined to form a high diversity ecosystem of coral reefs. In this investigation, the first hypothesis that recruitment assemblage is different among season, is tested. The study site is located in the coral reef of Kenting in southern Taiwan. We put out recruitment panels to simulate space generated after disturbance, at two-month intervals; then we checked the abundance of sessile fauna on the inside and outside surface of plates. A total of 17 zoological taxa was identified and numbered. Then Primer was used to ordinate the assemblages of recruitment from different seasons. A significant seasonal effect was found. Thus the first stage of the Seasonal Recruitment Hypothesis was supported.

This study examined the participation rates and performance results of students with emotional disturbance (ED) in a statewide reading assessment. Public school districts in Texas use the Texas Assessment of Knowledge and Skills (TAKS) test in assessing the reading performance of their students in grades 3 through 8 and in grade 10. Factors of gender, ethnicity, cognitive ability, school level socio-economic status and instructional setting in reading were examined. This study found that 58% of students with emotional disturbance enrolled in grades 3 through 8 and in grade 10 participated in the 2007 TAKS reading assessment. Implications include differences by sub grouping of students with ED. This study also found that 44 % of those students with emotional and behavioral disorders enrolled in the grades who took the test met proficiency standards on the TAKS reading assessment in 2007. Chi square analysis showed that there is a significant relationship between students’ instructional setting in reading and both their participation in and their performance on the TAKS Reading Assessment. Logistic regression analyses results showed that instructional setting in reading can be used as a predictor of both a student’s participation in and performance on the TAKS Reading Assessment.

There is a large body of research showing that sleep disorders are becoming more prevalent, especially in developing children in the United States. The negative effects of sleep disorders are well researched in adults. One such negative effect is the connection between sleep disorders and mental health disorders. Though this connection is well researched in adults, less is known about the connection between sleep disorders and mental health in developing children. The primary purpose of this paper is to review existing literature on the negative effects of sleep disorders, the causes of sleep disorders in children, and how sleep disorders may affect the mental well-being of developing teenagers in their time of vulnerability.

Disturbance plays integral role in the vegetative communities and succession in northern Alberta. Fire is the most common natural disturbance, and oil industry disturbance is a rapidly increasing anthropogenic disturbance on the landscape. In situ extraction of deep oil sands is increasing across Alberta, and with it, minimum disturbance sites used for seismic exploration and natural gas extraction also increase. To determine how these sites recover after disturbance, a 21 year chronosequence was established to address the following questions: 1) How do the plant communities differ between natural bogs, recently burned bogs, and bogs disturbed by `minimum disturbance petroleum industry activities? 2) How do the environmental conditions compare between undisturbed bogs, burned bogs, and bogs disturbed by `minimum disturbance' petroleum industry activities? 3) What is the revegetation pathway of minimum disturbance sites disturbed over the 21 year period? 4) What is the revegetation pathway of the burned bogs over the 21 year disturbance span? and 5) How does the (anthropogenic) minimum disturbance revegetation pathway compare to that of the (natural) fire disturbed bogs? To answer these questions 55 stands were sampled. The plant species were identified and abundance recorded, water chemistry was analyzed, shade recorded, depth to water measured, and oldest trees aged. Bog plant communities and environmental conditions at sites surveyed are similar to one another. Burned bogs were also similar in chemistry, vegetation, and physical traits of the sites. Minimum disturbance sites were quite varied in plant species and environmental conditions studied. A minimum disturbance revegetation could not be determined due to the amount variation in plant species and abundances between minimum disturbance sites of the same age. Burned bogs showed more predictable species interactions: Polytrichum strictum establishes early and subsequently declines. Sphagnum fuscum becomes dominant between 15 and 20 years after disturbance, and Picea mariana returns to burned sites between 1 and 5 years after fire and continues to increase in density. Minimum disturbance sites do not recover in a predictable manner, and some sites become rich fens. It is not clear if these sites will return to the pre-disturbance mature bog community, but burned bogs have a community closely resembling a mature bog after 20 years of revegetation. Documentation of pre-disturbance conditions and operational protocols is recommended in order to further understand sources of cation rich waters that could yield rich fen habitats.

Master of Science / Department of Biology / Jack Cully, Jr. / Disturbance is defined as any discrete event that disrupts ecosystem, community, or population structure and changes resources, substrate availability, or the physical environment. Habitat use by an organism is based on its perception of where to maximize its own fitness, and can be altered in response to disturbance-induced changes in resources, substrate, or physical features modified by disturbance. Disturbance-induced changes to vegetation structure reshape a small mammal’s surrounding physical environment and/or resources, and may influence its utilization of an area. Effective wildlife and resource management is dependent on a thorough understanding of how individual species and communities utilize their surroundings and how disturbance affects a species’ response to changes in its surroundings. We investigated seasonal habitat associations of three small mammal species and for overall species diversity across a gradient of military combat-vehicle disturbance intensities at the Fort Riley Military Reservation, Kansas. Deer mouse (Peromyscus maniculatus) abundance did not vary across a categorical gradient of disturbance created by military-combat vehicles, regardless of season. Western harvest mouse (Reithrodontomys megalotis) abundance was associated with more highly disturbed areas irrespective of season. Prairie vole (Microtus ochrogaster) abundance was associated with habitat that was less disturbed in the spring but more highly disturbed in the fall. Shannon diversity of the small mammal community was higher in the more highly disturbed areas regardless of season. This research shows that small mammals respond to disturbances created by military training with combat vehicles in a species-specific manner, and indicates that there may be differences in the effects of military training versus natural or agricultural disturbances on the abundance and diversity of small mammals. This is an important consideration given that the Department of Defense manages more than 12 million ha of land in the United States, and is charged under the Sikes Act with conserving natural resources on these lands, including biological diversity. Thus, the findings of other ecological research on the effects of disturbance on small mammals may not be directly applicable to the types of disturbances that occur on military lands, which underscores the need for further research on the specific effects of military-training activities on species’ responses.

The objective of this study was to examine the distribution of exotic plants and determine the potential threats in the mixedwood section of the boreal forest. The invasion of exotic plants into natural areas is a growing concern among ecologists. Exotic species have no previous exposure to the invaded area and have been introduced, either intentionally or accidentally, by humans. These plants have the potential to suppress surrounding vegetation and acquire the majority of available resources. This dominance alters important ecosystem functions and negatively affects ecosystem structure and composition. This study examined three types of land use (roadside right-of-way maintenance, timber harvesting and wildfire) to identify the density, frequency and cover of exotic plants within the mixedwood forest. There were also separate categories of the time since disturbance (re-current, recent and mature) for each disturbance type. Data were collected in the summer field seasons of 2000 and 2001 in and nearby the Prince Albert Model Forest (approximately 70 km north of Prince Albert, Saskatchewan). Surveying was completed in mature forest, harvested and wildfire areas using 10 x 10 m quadrats. These quadrats were adjacent to or remote from roadside right-of-ways that were deliberately seeded with exotic species. Seeding the right-of-ways with exotic species occurred along principal and secondary highways. Surveying was also conducted within roadside right-of-ways using 1 x 1 m quadrats. These quadrats were adjacent to the recently disturbed and mature quadrats surveyed in the previous year. Each plant species observed in the quadrats had a cover value assigned, while stem counts were also conducted for exotic species. A total of 23 exotic species were observed within the quadrats. The exotic herb species belong to the Gramineae (9 species), Leguminosae (7), Compositae (5) families with one species each in Plantaginaceae and Boraginaceae. No exotic trees or shrubs were observed within the study sites. Areas that were recently disturbed either by timber harvesting or wildfire had 6 different exotic species with an average density of 0.2 ± 0.1 stems/m2 and a frequency of 72 %. Similar exotic frequencies and species in both recently harvested and burned survey sites suggests that these disturbances have a comparable affect on exotic distributions. Exotic species capable of wind dispersal had the highest frequencies in the recently disturbed survey sites. Common dandelion (Taraxacum officinale) had a frequency of 57 %, perennial sow thistle (Sonchus arvensis) was observed in 38 % of the sites and annual hawksbeard (Crepis tectorum) was at 25 %. Mature forest had a lower population of exotic plants, with only 2 exotic species observed. Taraxacum officinale and Canada bluegrass (Poa compressa) were observed in 13 % of the mature quadrats with an average density of 0.002 ± 0.002 stems/m2. The right-of-way quadrats contained the highest amount of exotics with 22 observed species. The average density of exotic species in roadside right-of-ways was 117 ± 22 stems/m2 with 94 % of the quadrats containing at least one exotic plant. The deliberate introduction, frequency of disturbance and the physical environment of roadside right-of-ways appear to influence the distribution of exotic plant species. The most frequently observed exotic species in the right-of-way areas were Taraxacum officinale (observed in 73 % of the quadrats at 8 stems/m2) followed by alsike clover (Trifolium hybridum at 45 % and 17 stems/m2), Sonchus arvensis (43 % and 4 stems/m2), creeping red fescue (Festuca rubra at 36 % and 31 stems/m2) and smooth brome grass (Bromus inermis at 31 % and 17 stems/m2). These species are either common in urban areas, agricultural weeds or have been deliberately seeded into right-of-way areas. The distribution of exotic species suggests that land use contributes to increased densities and frequencies of exotic plants. Each exotic species observed was ranked according to a system developed by Hiebert and Stubbendieck (1993). The ranking system was used to determine the current and potential threat of exotic plant species to become detrimental to ecosystem structure, composition and function. The ranking identified 14 species that were a lesser threat and easy to control, 8 species that were a lesser threat and hard to control, and one species, Bromus inermis, that was ranked as a serious threat and hard to control. Additional monitoring is required as the species observed in this study may be exhibiting a lag phase of population expansion, which typically precedes an exponential increase. Other species (scentless chamomile (Matricaria perforata) and caragana (Caragana arborescens)) that were not observed in the study area, but are known to occur within the region, are also a concern with respect to future exotic species invasions. Anticipated climatic changes are also expected to increase the distribution of exotic species as changes to environmental attributes will produce a longer growing season and increased plant growth and productivity.

The objective of this study was to examine the distribution of exotic plants and determine the potential threats in the mixedwood section of the boreal forest. The invasion of exotic plants into natural areas is a growing concern among ecologists. Exotic species have no previous exposure to the invaded area and have been introduced, either intentionally or accidentally, by humans. These plants have the potential to suppress surrounding vegetation and acquire the majority of available resources. This dominance alters important ecosystem functions and negatively affects ecosystem structure and composition. This study examined three types of land use (roadside right-of-way maintenance, timber harvesting and wildfire) to identify the density, frequency and cover of exotic plants within the mixedwood forest. There were also separate categories of the time since disturbance (re-current, recent and mature) for each disturbance type. Data were collected in the summer field seasons of 2000 and 2001 in and nearby the Prince Albert Model Forest (approximately 70 km north of Prince Albert, Saskatchewan). Surveying was completed in mature forest, harvested and wildfire areas using 10 x 10 m quadrats. These quadrats were adjacent to or remote from roadside right-of-ways that were deliberately seeded with exotic species. Seeding the right-of-ways with exotic species occurred along principal and secondary highways. Surveying was also conducted within roadside right-of-ways using 1 x 1 m quadrats. These quadrats were adjacent to the recently disturbed and mature quadrats surveyed in the previous year. Each plant species observed in the quadrats had a cover value assigned, while stem counts were also conducted for exotic species. A total of 23 exotic species were observed within the quadrats. The exotic herb species belong to the Gramineae (9 species), Leguminosae (7), Compositae (5) families with one species each in Plantaginaceae and Boraginaceae. No exotic trees or shrubs were observed within the study sites. Areas that were recently disturbed either by timber harvesting or wildfire had 6 different exotic species with an average density of 0.2 ± 0.1 stems/m2 and a frequency of 72 %. Similar exotic frequencies and species in both recently harvested and burned survey sites suggests that these disturbances have a comparable affect on exotic distributions. Exotic species capable of wind dispersal had the highest frequencies in the recently disturbed survey sites. Common dandelion (Taraxacum officinale) had a frequency of 57 %, perennial sow thistle (Sonchus arvensis) was observed in 38 % of the sites and annual hawksbeard (Crepis tectorum) was at 25 %. Mature forest had a lower population of exotic plants, with only 2 exotic species observed. Taraxacum officinale and Canada bluegrass (Poa compressa) were observed in 13 % of the mature quadrats with an average density of 0.002 ± 0.002 stems/m2. The right-of-way quadrats contained the highest amount of exotics with 22 observed species. The average density of exotic species in roadside right-of-ways was 117 ± 22 stems/m2 with 94 % of the quadrats containing at least one exotic plant. The deliberate introduction, frequency of disturbance and the physical environment of roadside right-of-ways appear to influence the distribution of exotic plant species. The most frequently observed exotic species in the right-of-way areas were Taraxacum officinale (observed in 73 % of the quadrats at 8 stems/m2) followed by alsike clover (Trifolium hybridum at 45 % and 17 stems/m2), Sonchus arvensis (43 % and 4 stems/m2), creeping red fescue (Festuca rubra at 36 % and 31 stems/m2) and smooth brome grass (Bromus inermis at 31 % and 17 stems/m2). These species are either common in urban areas, agricultural weeds or have been deliberately seeded into right-of-way areas. The distribution of exotic species suggests that land use contributes to increased densities and frequencies of exotic plants. Each exotic species observed was ranked according to a system developed by Hiebert and Stubbendieck (1993). The ranking system was used to determine the current and potential threat of exotic plant species to become detrimental to ecosystem structure, composition and function. The ranking identified 14 species that were a lesser threat and easy to control, 8 species that were a lesser threat and hard to control, and one species, Bromus inermis, that was ranked as a serious threat and hard to control. Additional monitoring is required as the species observed in this study may be exhibiting a lag phase of population expansion, which typically precedes an exponential increase. Other species (scentless chamomile (Matricaria perforata) and caragana (Caragana arborescens)) that were not observed in the study area, but are known to occur within the region, are also a concern with respect to future exotic species invasions. Anticipated climatic changes are also expected to increase the distribution of exotic species as changes to environmental attributes will produce a longer growing season and increased plant growth and productivity.