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Our research centered on developing the Conservation Science and Technology Identity (CSTI) instruments as an empirical way to measure STEM identities and the intersection of identity constructs such as competence, performance, recognition, and ways of seeing and being. The surveys were used in a large funded multi‐year project for teens and adults learning geospatial technologies and conservation science to use in intergenerational community conservation projects. We investigated whether an informal STEM learning program was developing new STEM identities or advancing well‐developed identities. The instruments' content validity was determined through a vetting process from national STEM identity research experts. Reliability was estimated with Cronbach coefficient alpha. Mann‐Whitney and Wilcoxon Signed Rank tests were used to determine participants' STEM identities and the workshop's effect on specific identity constructs. We found teens and adults had historically similar STEM identities, with stronger conservation science than technology. Both science and technology competences, as well as technology ways of seeing and being, significantly increased, suggesting CSTI can be a valuable instrument in empirically assessing STEM identities. [ABSTRACT FROM AUTHOR]

Aim We present a model to account for self-assembly of the slough–ridge–tree island patterned landscape of the central Everglades in southern Florida via feedbacks among landforms, hydrology, vegetation and biogeochemistry. We test aspects of this model by analysing vegetation composition in relation to local and landscape-level drivers. Location We quantified vegetation composition and environmental characteristics in central Water Conservation Area (WCA) 3A, southern WCA-3A and southern WCA-3B in southern Florida, based on their divergence in water management and flow regimes over the past 50 years. Methods In 562 quadrats, we estimated species coverages and quantified maximum, minimum and average water depth, soil depth to bedrock, normalized difference vegetation index (NDVI) and proximity to the nearest tree island. We used non-metric multi-dimensional scaling (NMS) to relate compositional variation to local and landscape-level factors, and evaluated environmental differences among eight a priori vegetation types viaanova. Results Water depth and hydroperiod decreased from sloughs to ridges to tree islands, but regions also differed significantly in the abundance of several community types and the hydroregimes characterizing them. NMS revealed two significant axes of compositional variation, tied to local gradients of water depth and correlated factors, and to a landscape-scale gradient of proximity to tall tree islands. Sawgrass height and soil thickness increased toward higher ridges, and NDVI was greatest on tree islands. Main conclusions This study supports four components of our model: positive feedback of local substrate height on itself, woody plant invasion and subsequent P transport and concentration by top predators nesting on taller tree islands, compositional shifts in sites close to tree islands due to nutrient leakage, and flow-induced feedback against total raised area. Regional divergence in the relationship of community types to current hydroregimes appears to reflect a lag of a few years after shifts in water management; a longer lag would be expected for shifts in landscape patterning. Both local and landscape-level drivers appear to shape vegetation composition and soil thickness in the central Everglades. [ABSTRACT FROM AUTHOR]

Lygodium microphyllum(Cav.) R. Br. (Lygodiaceae) is a climbing fern that is becoming one of the worst non-indigenous invasive plant species in the greater Everglades ecosystem of southern Florida, USA. We examined the fern across a range of scales including the seasonality of its spore production, its height growth within infested sites and its community ecology. These attributes, combined with a series of aerial transects that identifiedL. microphylluminfestations across southern Florida, were used to develop a spatial model to predict its future spread in the Everglades landscape. The model shows that this non-indigenous invader could become widely established throughout the Everglades by 2014. Although several factors, such as release from natural enemies, may help explain the invasion success ofL. microphyllum, it appears likely that traits related to its reproduction, such as propagule pressure, and its ability to grow in a low-light understorey environment, may be among the most important in explaining its ability to invade both disturbed and undisturbed areas far from source populations. [ABSTRACT FROM AUTHOR]

Examines the effect of culture system and population source on sexual expression and sporophyte production for two invasive fern species in Florida. Evidence showing that both the Lygodium microphyllum and the Lygodium japonicum were capable of intragametophytic selfing; Percentage of both species studied that produced sporophytes; Ability of the Lygodium microphyllum to display the ability to reproduce via intergametophytic crossing.

Evaluates the use of cold plasma chemistry technology in modifying seed germination performance. Delay in germination; Dependence of the degree of delay on the amount of coating applied; Result of treating seeds with cyclohexane; Mode of action of the plasma coating.

Impacts of defoliation on the growth and physiology of sugar maple (Acer saccharum Marsh.) and trembling aspen (Populus tremuloides Michx.) were examined in ambient and CO2-enriched atmospheres. Saplings were grown for 70 d in controlled environments, wherein CO2 mole fractions averaged either 356 μmol mol ¹ or 645 μmol mol ¹, under a PPF of 500 μmol m ² s ¹. On day 49 of the study, 50e2 a of the leaf area was removed from a subset of each species in both CO2 environments. Relative growth rate (RGR) and its physiological and morphological determinants were monitored before and after defoliation. For non-defoliated saplings of both species, a slight stimulation of non (c. 5 D c) in elevated CO2 led to a modest increase (9 11 %) in final sapling weight. In the case of maple, the minimal growth response corresponded with minor CO2 effects on specific leaf area (SLA) and leaf weight ratio (LWR), and an apparent CO2-induced down-regulation of photosynthetic metabolism. For aspen, the CO2 stimulation of photosynthesis was largely offset by a decrease in SLA. Responses to defoliation differed markedly between species and CO2 environments. Defoliation decreased maple RGR in ambient CO2, whereas the opposite occurred in elevated CO2. The latter led to complete recovery of plant weight (compensation), and was attributed to a defoliation-induced increase in carbon allocation to new leaves, along with a reversal of photosynthetic CO2 acclimation in that foliage. In both environments, aspen RGH increased after defoliation, facilitating almost full compensation. Defoliation increased light penetration into the aspen canopy, and it was estimated that the resultant stimulation of photosynthesis in lower leaves would have more than offset the concomitant decrease in LWR. CO2 enrichment might substantially enhance the ability of certain tree species to recover from herbivory. Moreover, responses to elevated CO2 might he largest in the presence of stresses, such as herbivory, that decrease plant source:sink ratios. [ABSTRACT FROM AUTHOR]

Due to their different physiological effects, elevated carbon dioxide and elevated ozone might have interactive Impacts on plants, and differentially so on plants differing in photosynthetic pathway and growth rate. To test Several hypotheses related to these issues, we examined the physiological, morphological and growth responses of Six perennial species grown at various atmospheric concentrations of carbon dioxide and ozone. The species involved (two C3 trees: Populus tremuloides Michx., Quercus rubra L.; two C2 grasses: Agropyron smithii Rybd., Koeleria cristataL.; two C4 grasses: Bouteloua curtipendula Michx., Schizachyrium scoparium Michx.) differed in growth form, stomatal conductance and photosynthetic pathway. In situ photosynthesis, relative growth rate (RGR) and its determinants (leaf area ratio, specific leaf area, leaf weight ratio and root weight ratio) were determined via sequential harvests of seedlings that were grown in all combinations of 366 or 672 μmol mol-1 CO2 and 3 or 95 nmol mol-1 O3 over a 101-d period. Elevated CO2 had minimal effect on either photosynthesis or RGR. By Contrast, RGR for all six species was lower in high O3 concentrations at ambient CO2, significantly so in A. smithii and P. tremuloides. Five of the six species also exhibited reductions in in situ photosynthesis at ambient CO2 in high-O3-grown compared with low-O3-grown plants. For all species, these O3-induced reductions in RGR and Photosynthesis were absent in the elevated CO2 environment. Root weight ratio was significantly reduced by elevated O3 in A. smithii and P. tremuloides in ambient but not elevated CO2. Species with high stomatal Conductance were the most susceptible to oxidant injury, while those with low stomatal conductance, such as the C4 species and Q. rubra, were not as detrimentally affected by O3. Elevated levels of CO2 will reduce stomatal Conductance and O3 uptake, and might therefore reduce the potential for oxidant damage. However, there wan Stronger relationship of the percent reduction in whole-plant mass due to O3, related to the ratio of photosynthesis to Stomatal conductance. In general, results of this study of six functionally diverse plant species suggest that O3 Pollution effects on carbon balance and growth are likely to he ameliorated by elevated concentrations of atmospheric CO2. [ABSTRACT FROM AUTHOR]

Seedlings of three species native to central North America, a C3 tree, Populus tremuloides Michx., a C3 grass, Agropyron smithii Rybd., and a C4 grass, Bouteloua curtipendula Michx., were grown in all eight combinations of two levels each of CO2, O3 and nitrogen (N) for 58 days in a controlled environment. Treatment levels consisted of 360 or 674 μmol mol‐1 CO2, 3 or 92 nmol mol‐1 O3, and 0.5 or 6.0 mM N. In situ photosynthesis and relative growth rate (RGR) and its determinants were obtained at each of three sequential harvests, and leaf dark respiration was measured at the second and third harvests. In all three species, plants grown in high N had significantly greater whole‐plant mass, RGR and photosynthesis than plants grown in low N. Within a N treatment, elevated CO2 did not significantly enhance any of these parameters nor did it affect leaf respiration. However, plants of all three species grown in elevated CO2 had lower stomatal conductance compared to ambient CO2‐exposed plants. Seedlings of P. tremuloides (in both N treatments) and B. curtipendula (in high N) had significant ozone‐induced reductions in whole‐plant mass and RGR in ambient but not under elevated CO2. This negative O3 impact on RGR in ambient CO2 was related to increased leaf dark respiration, decreased photosynthesis and/or decreased leaf area ratio, none of which were noted in high O3 treatments in the elevated CO2 environment. In contrast, A. smithii was marginally negatively affected by high O3. [ABSTRACT FROM AUTHOR]