A phenological model of gypsy moth egg development is proposed that distinguishes three phases of egg development, prediapause, diapause and postdiapause. A technique of measuring respiration rates of individual eggs was developed and respiration rate was used as a physiological variable to distinguish the phases. The pattern of respiration rate provided strong evidence in support of three distinct developmental phases. Respiration rate developed embryos declined sharply as prediapause was entered and rose sharply when diapause was completed. When the effect of age on respiration rate was removed, temperature had a uniform effect on respiration rate throughout the egg stage. A 10°C decrease in temperature caused an approximate 0.4 fold decrease in respiration rate, indicating that eggs in diapause are as equally responsive to temperature as egg in a nondiapause phase. Developmental rate in prediapause was strongly temperature-dependent, and the relationship was described by a non-linear function. Prediapause duration was approximately 13 days at 31°C. The depletion of stored triglycerides was strongly linked to the completion of prediapause. Developmental rate in postdiapause was found to be temperature- and age-dependent. Developmental response to temperature was relatively weak and linear at the onset of postdiapause. As postdiapause advanced, the response became stronger and non-linear. The temperature- and age-dependent developmental response was fully described by the temperature-dependent developmental response at the onset of postdiapause, and by a temperature-dependent rate change parameter. / Ph. D.

Monitoring and understanding plant phenology is becoming an increasingly important way to identify and model global changes in vegetation life cycle events. Although numerous studies have used synoptically sensed data to study phenological patterns at the continental and global scale, relatively few have focused on characterizing the land surface phenology of specific ecosystems. Mountain environments provide excellent examples of how variations in topography, elevation, solar radiation, temperature, and spatial location affect vegetation phenology. High elevation biomes cover twenty percent of the Earth's land surface and provide essential resources to both the human and non-human population. These areas experience limited resource availability for plant growth, development, and reproduction, and are one of the first ecosystems to reflect the harmful impact of climate change. Despite this, the phenology of mountain ecosystems has historically been understudied due to the rough and variable terrain and inaccessibility of the area. Here, we use two MODIS/Terra satellite 16-day products, Vegetation Index and Nadir BRDF Adjusted Reflectance, to assess start of season (SOS) for the 2007 calendar year. Independent data for elevation, slope, aspect, solar radiation, and temperature as well as longitude and latitude were then related to the SOS output. Based on the results of these analyses, we found that SOS can be predicted with a significant R² (0.55-0.64) for each individual zone as well as the entire western mountain range. While both elevation and latitude have significant influences on the timing of SOS for all six study areas. When examined at the regional scale and accounting for aspect, SOS follows closely with Hopkins' findings in regard to both elevation and latitude. / Master of Science

The pine bark adelgid, Pineus strobi (Hemiptera: Adelgidae) is a native herbivore of eastern white pine, Pinus strobus (Pinales: Pinaceae), in eastern North America. It is a sessile insect that settles on P. strobus and inserts its stylet bundle to feed on the tree’s phloem. Although P. strobi is not considered a serious pest, it shares its range with the invasive hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae). Predators introduced as biological control agents of A. tsugae interact with P. strobi and its native predators, including Laricobius rubidus LeConte (Coleoptera: Derodontidae). Prior to this study, little work had been done to document the phenology or predators of P. strobi, particularly in its southern range. In the present study, the phenology of P. strobi is reported in southwestern Virginia. Patterns in overwintering population dynamics varied notably from those described from this species’ northern range. The number of annual generations could not be measured due to overlap following two distinct spring generations. Adult body size varied seasonally and was greatest in the spring. Variation between observations from the northern and southern ranges of P. strobi indicate phenological plasticity that informs biological control efforts and offers insight into implication of climatic effects on population dynamics of this and related species. Arthropod predators associated with P. strobi in forests of southwest Virginia were collected during a two-year survey. Morphology and DNA barcoding were used for identification. Species of predators found included: Laricobius rubidus (Coleoptera: Derodontidae), a native adelgid specialist, and two species from the dipteran family Chamaemyiidae, Leucopis piniperda Malloch and L. argenticollis Zetterstedt, which are adelgid specialists. Members of the families Cecidomyiidae, Coccinellidae, Chrysopidae, Hemerobiidae, and Syrphidae were also recovered. Most diverse were the Cecidomyiidae, with 15 different species inferred from their DNA barcodes. Additional work was performed to quantify supercooling points of L. rubidus collected from November – December 2016. These will be compared to those of other Laricobius species in a parallel study. Knowledge of this predator complex is beneficial to describing P. strobi ecology, and also with regard to potential biological control of invasive adelgids in the same region. / Ph. D.

The spotted lanternfly, Lycorma delicatula (White) (Hemiptera: Fulgoridae), is a new invasive insect from Asia that is currently spreading in the Mid-Atlantic region of the US, where it has become a pest of economic concern for many industries in their invaded range. The purpose of this research was to document L. delicatula phenology in Virginia, their feeding impact to trees, and to test a rearing protocol in quarantine laboratory conditions. First, using field plots and weekly observational surveys, L. delicatula phenology was documented in 2019 and 2020 in Winchester, Virginia. I showed that L. delicatula were active from late April into November for each sampling year, and that the timing of life stage events varied only slightly between years. I also calculated cumulative average growing degree days for each life stage event using a lower developmental threshold of 10°C. Additionally, I confirmed that the host range of L. delicatula narrows as they progress through development. These results will help growers and land managers develop integrated pest management plans targeting L. delicatula. Second, dendrochronological methods were used to quantify L. delicatula feeding injury to Ailanthus altissima (Miller) Swingle (Sapindales: Simaroubaceae), Juglans nigra L. (Fagales: Juglandaceae), and Liriodendron tulipifera L. (Magnoliales: Magnoliaceae). Two sites in Pennsylvania that have experienced high populations and heavy feeding pressure from L. delicatula since 2016 were used to collect tree cores for analysis. I found evidence suggesting L. delicatula is capable of reducing the growth of A. altissima, but did not find the same evidence in the wood of the other tree species tested. Additionally, I found evidence that systemic insecticide treatments may reduce or prevent damage to A. altissima fed on by L. delicatula. Additional dendrochronological studies on the damage inflicted by L. delicatula feeding could shed light on the long-term impact of this new invasive tree pest. Lastly, a protocol for rearing L. delicatula was tested inside Virginia Tech's Insect Quarantine Laboratory. Three different cuttings of A. altissima (apical meristems, epicormic shoots, and field collected foliage) were tested to determine the best food source for L. delicatula in quarantine laboratory conditions. Overall, I did not find a significant difference between food treatments, however a greater proportion of third instars developed into fourth instars in the apical meristem treatment. I suggest future L. delicatula rearing research include the use of potted plants and/or multiple species. Though I had low success in rearing adult L. delicatula to produce egg masses, this method may prove useful for rearing early instars from eggs or sustaining field collected specimens for short durations. Research expanding our knowledge of L. delicatula will help us reach our goal of more effectively managing this pest species in the future. / Master of Science in Life Sciences / The spotted lanternfly, Lycorma delicatula (White), is a new invasive pest species impacting the eastern and northeastern regions of the United States. This insect uses its straw-like mouth parts to feed on the sap of many different plants including fruit trees, grapes, and several important ornamental and timber trees. Though they do not bite or sting, feeding can result in wilting, the growth of sooty mold, and sometimes plant mortality, making them an economic and nuisance pest in their invaded range. This research primarily focused on studying the timing of the spotted lanternfly's life cycle, feeding impact to trees, and a method for raising them in the laboratory for research purposes. The life-cycle of the spotted lanternfly was documented over two growing seasons in Winchester, VA and the timing of each life stage was shown to be similar between years. Additionally, it was confirmed that the spotted lanternfly feeds on fewer host species as it develops into an adult. Tree-ring analysis was used to identify spotted lanternfly feeding injury to tree-of-heaven, black walnut, and tulip poplar. I found evidence suggesting spotted lanternfly feeding can cause reduced growth in tree-of-heaven, but did not find similar evidence in the other species tested. A laboratory colony of spotted lanternflies would prove beneficial for additional research on this insect. I tested three different types of branches cut from the tree-of-heaven to identify the best food source for spotted lanternfly in laboratory conditions. The findings of this research will help develop pest management strategies to reduce the impact of this new pest in the US.

Yeung, Fai Fai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 212-243). / Abstracts in English and Chinese. / Acknowledgements --- p.i / Abstract (English) --- p.iv / Abstract (Chinese) --- p.x / Contents --- p.xiv / List of Tables --- p.xxii / List of Figures --- p.xxiv / Chapter Chapter 1 --- General Introduction --- p.1 / Chapter I.1 --- General Ideal and Background on Seasonality and Phenology --- p.1 / Chapter I.I.1 --- Seasonality Study of Terrestrial Plant --- p.2 / Chapter I.I.2 --- Study on Seasonality of Marine Algae --- p.3 / Chapter I.2 --- Life History and Seasonality of Sargassum spp --- p.4 / Chapter I.2.1 --- Why Study Sargassum seasonality --- p.5 / Chapter I.2.2 --- Spatial and Temporal Variations in Seasonality of Sargassum spp --- p.6 / Chapter I.2.2.1 --- Differences in seasonality based on locality --- p.7 / Chapter I.2.2.2 --- Interspecific differences in seasonality --- p.7 / Chapter I.2.2.3 --- Intra-specific differences in seasonality --- p.8 / Chapter I.2.3 --- Studies on Seasonality of Sargassum spp. in Hong Kong --- p.9 / Chapter I.3 --- Photosynthesis of Seaweeds --- p.11 / Chapter I.3.1 --- Photosynthesis - Ecophysiological Indicator for Seasonality --- p.11 / Chapter I.3.2 --- Photosynthesis in Different Parts of Seaweeds --- p.13 / Chapter I.3.3 --- New Methodology to Study Photosynthesis --- p.15 / Chapter I.4. --- Scope and Significance of this Thesis Research --- p.16 / Chapter I.4.1 --- General Objectives --- p.17 / Chapter I.4.2 --- Study Organisms --- p.17 / Chapter I.4.2.1 --- Sargassum hemiphyllum (Turner) C Agardh --- p.18 / Chapter I.4.2.1 --- Sargassum siliquastrum (Turner) C Agardh --- p.18 / Chapter I.4.3 --- Study Site --- p.19 / Chapter I.4.3.1 --- Lung Lok Shui (LLS) --- p.19 / Chapter I.4.3.2 --- Lung Yue Tsui (LYT) --- p.19 / Chapter I.4.3.3 --- Lo Fu Ngan (LFN； --- p.20 / Chapter I.4.3.4 --- Lung Ha Wan (LHW) --- p.21 / Chapter I.4.3.5 --- Clear Water Bay (CWB) --- p.21 / Chapter I.4.3.6 --- Tai Tam Wan --- p.21 / Chapter I.4.3.6.1 --- Tai Tam Wan (rock shore) (TTW(rs)) --- p.21 / Chapter I.4.3.6.2 --- Tai Tam Wan (sea school) (TTW (ss)) --- p.21 / Chapter I.5 --- Organization Chart --- p.22 / Chapter Chapter 2 --- Comparative Seasonality of Sargassum siliquastrum and S hemiphyllum in Hong Kong S.A.R --- p.35 / Chapter II.1 --- Introduction --- p.35 / Chapter II.2 --- Materials and Methods --- p.39 / Chapter II.2.1 --- Study Sites --- p.39 / Chapter II.2.2 --- Seasonal Variation in Size and Reproductive Status of Sargassum Plants --- p.39 / Chapter II.2.3 --- "Seasonal Variation in Growth Rates, Population Structures and Densities" --- p.42 / Chapter II.2.4 --- Comparisons between Populations of Sargassum spp --- p.43 / Chapter II.2.5 --- Seasonal Changes in Environmental Parameters --- p.44 / Chapter II.2.6 --- Statistical Analysis --- p.45 / Chapter II.3 --- Results --- p.46 / Chapter II.3.1 --- Seasonality of S. siliquastrum along the Latitudinal Gradient from North to South of Hong Kong --- p.46 / Chapter II.3.1.1 --- Seasonal variation of mean thallus length --- p.46 / Chapter II.3.1.2 --- Seasonality in reproduction --- p.47 / Chapter II. 3.1.3 --- Growth rates --- p.49 / Chapter II.3.1.4 --- Seasonal variations in mean density --- p.50 / Chapter II. 3.1.5 --- Population structure --- p.51 / Chapter II.3.2 --- Seasonality of S. siliquastrum along the Vertical Gradient of Different Depths --- p.56 / Chapter II.3.2.1 --- Seasonal variation of mean thallus length --- p.56 / Chapter II. 3.2.2 --- Seasonality of reproduction --- p.56 / Chapter II.3.2.3 --- Growth rates --- p.57 / Chapter II.3.2.4 --- Seasonal variations in mean density --- p.58 / Chapter II.3.2.5 --- Population Structure --- p.59 / Chapter II.3.3 --- Seasonality of S. hemiphyllum along the Latitudinal Gradient from North to South of Hong Kong --- p.63 / Chapter II. 3.3.1 --- Seasonal variation of mean thallus length --- p.63 / Chapter II. 3.3.2 --- Percentage of reproductive plants --- p.63 / Chapter II.3.3.3 --- Growth rates --- p.64 / Chapter II.3.4 --- Comparison of Seasonality between S siliquastrum and S. hemiphyllum --- p.64 / Chapter II.3.5 --- Comparison of Environmental Parameters among Sites --- p.66 / Chapter II.4 --- Discussion --- p.69 / Chapter II.4.1 --- Inter-specific Comparison on Sargassum phenology --- p.69 / Chapter II.4.2 --- Intra-specific Comparison on Sargassum phenology --- p.73 / Chapter II.4.2.1 --- Comparison along regional scale (> 100kms) geographical range --- p.73 / Chapter II. 4.2.2 --- Comparison along meso-scale (< 100kms) geographical range --- p.77 / Chapter II. 4.2.2.1 --- Comparison along meso-scale latitudinal gradient 一 S. siliquastrum --- p.78 / Chapter II.4.2.2.2 --- Comparison along meso-scale latitudinal gradient - S. hemiphyllum --- p.82 / Chapter II. 4.2.2.3 --- Comparison along vertical depth gradient - S. siliquastrum --- p.87 / Chapter II.5 --- Summary --- p.91 / Chapter Chapter 3 --- Photosynthetic activities of Sargassum siliquastrum and S hemiphyllum in Hong Kong S.A.R --- p.125 / Chapter III.l. --- Introduction --- p.125 / Chapter III.2. --- Materials and Methods --- p.128 / Chapter III.2.1 --- Seasonal Variation in Photosynthetic Activities of Sargassum spp. (Field Monitoring) --- p.128 / Chapter III.2.2 --- Seasonal Variation in Photosynthetic Activities of Sargassum spp. (Laboratory Measurement) --- p.130 / Chapter III.3 --- Results --- p.131 / Chapter III.3.1 --- Initial Preliminary Testing on Sampling Size for PAM Measurement --- p.131 / Chapter III.3.2 --- Seasonal Variations of Effective Quantum Yield (Field Monitoring) --- p.131 / Chapter III. 3.2.1 --- Intra-specific comparison along latitudinal gradient from north to south of Hong Kong 一 S siliquastrum --- p.131 / Chapter III. 3.2.2 --- Intra-specific comparison along latitudinal gradient from north to south of Hong Kong 一 S hemiphyllum --- p.134 / Chapter III.3.2.3 --- Intra-specific comparison along vertical depth gradient - S. siliquastrum --- p.136 / Chapter III.3.3 --- Seasonal Variations of Maximum Quantum Yield (Laboratory Measurement) and Comparative Photosynthesis of Different Parts of Sargassum spp --- p.137 / Chapter III.4 --- Discussion --- p.139 / Chapter III.4.1 --- Seasonal Photosynthetic Performances of S siliquastrum and S. hemiphyllum --- p.139 / Chapter III.4.2 --- Different level of Photosynthesis in Various Parts of Sargassum spp --- p.146 / Chapter III.4.3 --- Comparative Photosynthesis from Different Depths --- p.153 / Chapter III.5. --- Summary --- p.155 / Chapter Chapter 4 --- Transplantation Experiment --- p.172 / Chapter IV.l. --- Introduction --- p.172 / Chapter VI.2. --- Materials and Methods --- p.174 / Chapter IV.2.1 --- Reciprocal Transplantation for S. siliquastrum --- p.174 / Chapter IV.2.2 --- Reciprocal Transplantation for S. hemiphyllum --- p.176 / Chapter VI.3. --- Results --- p.178 / Chapter IV.3.1 --- Reciprocal Transplantation for S. siliquastrum --- p.178 / Chapter IV.3.1.1 --- Mean thallus length --- p.178 / Chapter IV.3.1.2 --- Percentage of reproductive plants --- p.181 / Chapter IV.3.1.3 --- Photosynthetic effective quantum yield --- p.182 / Chapter IV.3.1.4 --- Survivorship --- p.183 / Chapter IV.3.2 --- Reciprocal Transplantation for S. hemiphyllum --- p.184 / Chapter IV.3.2. 1 --- Mean thallus length --- p.184 / Chapter IV.3.2.2 --- Percentage of reproductive plants --- p.185 / Chapter IV.3.2.3 --- Photosynthetic effective quantum yield --- p.186 / Chapter IV.3.2.4 --- Survivorship --- p.187 / Chapter IV.4 --- Discussion --- p.187 / Chapter IV.4.1 --- Transplantation Experiment for S. siliquastrum --- p.188 / Chapter IV.4.2 --- Transplantation Experiment for S. hemiphyllum --- p.192 / Chapter IV.5 --- Summary --- p.196 / Chapter Chapter 5 --- Summary and Conclusion --- p.204 / References --- p.212

The phenology of the three exotic pine bark beetles present in South Africa was determined in the south-western Cape Province. Results from weekly trapping of adult beetles using trap-logs over a period of five years showed that the different species had activity peaks at different times of the year. Hylastes angustatus was the most consistent with 95% of the beetles captured in September and October. The Orthotomicus erosus activity peak was more variable but always occurred in the summer months (October to February) when 84% of the beetles were captured. Hylurgus ligniperda was the most variable, being found in every month of the year, although an autumn peak representing 37% of the beetles occurred in April/May. Activity peaks of each species coincided with distinct climatic conditions. Buried and partially-buried pine logs placed vertically in the soil to simulate roots and stems of seedlings were used to determine the colonisation sites of the three bark beetle species. Ninety-eight percent of O. erosus beetles were found in the protruding parts of the logs while 86% of H. ligniperda beetles were found mainly below soil level. H. angustatus were intermediate, entering the logs at or just below the soil interface but colonising mainly the buried parts in which 64% of the beetles were found. Both H. angustatus and H. ligniperda were able to detect and colonise logs buried horizontally at depths of 400mm, but O. erosus beetles were unable to do so. For adequate protection of seedlings from bark beetles, insecticide should be applied to both stems and roots. The phenology of the indigenous pine needle feeders Oosomus varius (Curculionidae) and Prasoidea sericea (Chrysomelidae) was determined by counting, at weekly intervals, the number of beetles present on 10 young pine trees. The O. varius activity peak occurred in August where 42% of all beetles were active, with 87% of the beetles present in July, August and September. P. sericea also had their activity peak in August when 60% of all beetles were active, but with August and September alone accounting for 87% of the beetles. The occurrence of the activity peaks was consistent each year over the five-year study period. This information facilitates the correct timing of prophylactic insecticide sprays.

Subtropical deforestation in Latin America is thought to be driven by demand for agricultural land, particularly to grow soybeans. However, existing remote sensing methods that can differentiate crop types to verify this hypothesis require high spatial or spectral resolution data, or extensive ground truth information to develop training sites, none of which are freely available for much of the world. I developed a new method of crop classification based on the phenological signatures of crops extracted from multi-temporal MODIS vegetation indices. I tested and refined this method using the USDA Cropland Data Layer from Kansas, USA as a reference. I then applied the method to classify crop types for a study site in Pellegrini, Santiago Del Estero, Argentina. The results show that this method is unable to effectively separate summer crops in Pellegrini, but can differentiate summer crops and non-summer crops. Unmet assumptions about agricultural practices are primarily responsible for the ineffective summer crop classification, underlining the need for researchers to have a complete understanding of ground conditions when designing a remote sensing analysis.

Phenology is an integrative science that comprises the study of recurring biological activities or events. In an era of rapidly changing climate, the relationship between the timing of those events and environmental cues such as temperature, snowmelt, water availability, or day length are of particular interest. This article provides an overview of the observer-based plant phenology sampling conducted by the U.S. National Ecological Observatory Network (NEON), the resulting data, and the rationale behind the design. Trained technicians will conduct regular in situ observations of plant phenology at all terrestrial NEON sites for the 30-yr life of the observatory. Standardized and coordinated data across the network of sites can be used to quantify the direction and magnitude of the relationships between phenology and environmental forcings, as well as the degree to which these relationships vary among sites, among species, among phenophases, and through time. Vegetation at NEON sites will also be monitored with tower-based cameras, satellite remote sensing, and annual high-resolution airborne remote sensing. Ground-based measurements can be used to calibrate and improve satellite-derived phenometrics. NEON's phenology monitoring design is complementary to existing phenology research efforts and citizen science initiatives throughout the world and will produce interoperable data. By collocating plant phenology observations with a suite of additional meteorological, biophysical, and ecological measurements (e.g., climate, carbon flux, plant productivity, population dynamics of consumers) at 47 terrestrial sites, the NEON design will enable continental-scale inference about the status, trends, causes, and ecological consequences of phenological change.

Thesis (MSc)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: Species’ seasonal behaviour is of paramount importance in understanding community functioning and dynamics. Recently, plant phenology has further gained significance as a reliable indicator of climate change impacts. Despite the importance of understanding plant dynamics, there are relatively few plant phenological records for the sub-Antarctic region, and where records exist they are often not extensive. Sub-Antarctic Marion Island, typical of Southern Ocean Islands, offers a useful setting for addressing these knowledge gaps. This study documented the vegetative and reproductive phenologies (or aggregate phenological patterns) of twelve indigenous and three alien vascular plant species on the island. The phenological differences among the species and distinct seasonal groupings (e.g. early, intermediate and late species) were examined. I also investigated the phenological differences among the indigenous and alien plant species. Furthermore, the onset of selected reproductive phenophases from the current records was compared with historical records for determining the extent of climate change-related alterations in phenology. Phenological data were collected fortnightly on five, 5 m x 5 m permanent plots per species (except for a few species) for a full growing season. Thus the sample size is n = 5 for all plant species except for Crassula moschata (n = 4), Juncus effusus (n=4) and Rumex acetosella (n=1). Sites of the same species were separated by at least 500 m except for the alien plant, Juncus effusus, where all four known populations were selected despite two of these populations being < 500 m apart. This study indicated that Marion Island plants grow throughout the year with no major peaks except in Azorella selago and Acaena magellanica which showed winter dormancy. However, reproduction in most plant species predominately occurred in spring and summer months. Pringlea antiscorbutica and Poa cookii were the first two species to set flower buds in September while most species dispersed their seeds in summer except for Agrostis magellanica and Crassula moschata which dispersed in early autumn. Distinct from most temperate systems, the reproductive seasonality displayed by Marion Island plant species is explained more by daylength than by temperature, perhaps due to the region’s typical thermal aseasonality. Interestingly, many cooccurring species and/or clades across the Falkland, Kerguelen, Macquarie and South Georgia Islands also showed similar flowering onset date to the Marion Island plants, further confirming their daylength sensitivity. However, other external factors seem to come into play at later events of reproduction. Consequently, fruit maturation time of similar species across the sub-Antarctic islands varied substantially despite the plants having flowered in the same month. Although plant species showed similar reproductive seasonality, there were significant differences among species phenologies i.e. phenophase timing, duration and peak occurrence dates. However, using 95% confidence intervals of Generalized Linear Models weighted means, and/or one-way ANOVA (Tukey post hoc test), three homogenous sets of species (early, late, or intermediate onsets) were identified based on flower bud, flowering and seed dispersal phenophase onset dates. The homogenous species groupings observed for flower buds also remained unchanged during flowering onset except for Cotula plumosa and Callitriche antarctica which switched groups. As for the seed dispersal timing, the pattern was not consistent with that of the flower bud and flowering onset homogenous groupings, except for Acaena magellanica and Agrostis magellanica which remained in the early and late groups, respectively. Conversely, in the case of the timing of other phenophases (pollen release, fruit set and fruit ripening), entire phenophase durations, and peak occurrence dates, species overlapped greatly, resulting in an unbroken progression or continuum of phenology among species. Similarly, the three alien plant species investigated here (Cerastium fontanum, Juncus effusus and Rumex acetosella) showed no consistent phenological differences from the rest of the species. However, a widespread alien plant species on Marion Island, C. fontanum, reproduced for most of the year, although its reproduction peak was in summer months as was the case for the rest of the species. This study also indicated that indigenous plant species have altered their reproductive phenologies since 1965. Although the response was species-specific, the majority of plant species significantly delayed the onset of reproductive activities in 2007 by comparison with 1965. However, it is not clear if the observed species response was caused by the now drier and warmer Marion Island climate or by discrepancies in reporting in the earlier studies and/or sampling differences between the recent and historical records. Therefore, these results should be taken with caution. In conclusion, this research provided a detailed phenological dynamics record for vascular plant species on the island. Over time these records may be used as a basis for monitoring and modelling the impact of climate on plant phenology on the island. / AFRIKAANSE OPSOMMING: Spesies se seisoenale gedrag is van die allergrootste belang in die begrip van gemeenskapsfunksionering en dinamika. Meer onlangs het plant fenologie verdere betekenis verwerf as ‘n betroubare indikator vir die impakte van klimaatsverandering. Ondanks die belangrikheid om plant dinamika te verstaan, is daar relatief min plant fenologiese rekords vir die sub-Antarktiese streek en waar rekords wel bestaan is dit dikwels nie omvangryk nie. Sub- Antarktiese Marion Eiland, tipies van Suidelike Oseaan Eilande, bied ‘n nuttige ligging om hierdie kennis gapings aan te spreek. Hierdie studie het die vegetatiewe en voorplantingsfenologieë (of gesamentlike fenologiese patrone) van elf inheemse en drie uitheemse vaatplantspesies op die eiland gedokumenteer. Die fenologiese verskille tussen die spesies en duidelike seisoenale groeperings (bv. vroeë, intermediêre en laat spesies) is ondersoek. Ek het ook die betekenisvolle fenologiese verskille tussen die inheemse en uitheemse plantspesies ondersoek. Voorts, die aanvang van gekose voortplanting feno-fases van huidige rekords is vergelyk met historiese rekords om die mate van klimaatsverandering verbandhoudende veranderings in die fenologie te bepaal. Fenologiese data is twee weekliks ingesamel op vyf, 5 m x 5 m permanente plotte per spesie (behalwe vir ‘n paar spesies) vir ‘n volle groei seisoen. Dus, die insamelings grootte is n = 5 vir al die plantspesies behalwe vir C. moschata (n = 4), Juncus effusus (n=4) en Rumex acetosella (n=1). Persele vir dieselfde spesies is geskei deur ten minste 500 m, behalwe vir die uitheemse plant, Juncus effusus, waar al vier populasies wat bekend is gekies is, ten spyte daarvan dat twee van hierdie populasies < 500 m uitmekaar is. Hierdie studie het aangedui dat Marion Eiland plante regdeur die jaar groei, met geen belangrike spitstye nie, behalwe in Azorella selago en Acaena magellanica wat ‘n winter rusperiode wys. Hoe ookal, voortplanting in meeste van die plantspesies het hoofsaaklik voorgekom tussen die lente en somermaande. Pringlea antiscorbutica en Poa cookii was die eerste twee spesies om blomknoppe uit te stoot in September, terwyl die meeste spesies hulle sade versprei het gedurende die somer, behalwe vir Agrostis magellanica en Crassula moschata wat versprei het in vroeg herfs. Duidelik van meeste gematigde sisteme, word die voortplanting seisoenaliteit, getoon deur die Marion Eiland plantspesies, verduidelik meer deur daglengte as deur temperatuur, moontlik weens die streek se tipiese termiese a-seisoenaliteit. Interessant, baie spesies en/of afstameling-groeperings wat saam aangtref word dwarsoor die Falkland, Kerguelen, Macquarie en Suid Georgia Eilande wys ook soortgelyke bloei aanvangsdatums as die Marion Eiland plante, nog meer bevestigend van hulle dag-lengte sensitieweteit. Hoe ookal, ander eksterne faktore blyk betrokke te raak by latere gebeure van voortplanting. Gevolglik het vrug rypwordingstyd van dieselfde spesies oor die sub-Antarktiek noemenswaardig verskil, ten spyte daarvan dat die plante in dieselfde maand geblom het. Alhoewel plantspesies dieselfde voortplanting seisoenaliteit gewys het, was daar ‘n noemenswaardige veskil tussen spesie fenologieë, m. a. w. feno-fase tydsberekenning, tydsduur en spits voorkomsdatums. Hoe ookal, deur gebruik te maak van 95% betroubaarheid intervalle van Algemene Lineêre Modelle gewigte gemiddelde en/of een rigting ANOVA (Turkey post hoc toets), is drie homogene stelle van spesies (vroeë, laat en intermediêre aanvang) geïdentifiseer gebasseer op blomknop, bloei en saad verspreiding feno-fase aanvangsdatums. Die homogene spesie groeperings waargeneem op blomknoppe het ook onveranderd gebly gedurende bloei aanvang behalwe vir Cotula plumosa en Crassula antarctica wat groepe geruil het. Vir die saadverspreiding tydsberekenning was die patroon nie konstant met die van die blomknop en bloei aanvang homogene groepe nie, behalwe vir Acaena magellanica en Agrostis magellanica wat in die vroeë en laat groepe respektiewelik gebly het. Omgekeerd, in die geval van tydsberekenning van ander feno-fases (stuifmeel vrysetelling, vrugwerp, vrugrypwording), volledige feno-fase tydsduur en spits voorkomsdatums het spesies grootliks oorvleuel, wat ‘n ongebroke vordering of deurlopendheid van fenologie tussen die spesies tot gevolg het. Ooreenkomstig het die drie uitheemse spesies wat hier ondersoek is (Cerastium fontanum, Juncus effusus en Rumex acetosella) geen bestendige fenologiese verskille van die res van die spesies gewys nie. Hoe ookal, ‘n wydverspreide uitheemse spesie op Marion Eiland, Cerastium fontanum, het deur die meeste van die jaar voortgeplant, hoewel met ‘n voorplanting spits in die somer maande soos die res van die spesies. Hierdie studie dui ook aan dat inheemse plantspesies hulle voortplanting fenologieë verander het sedert 1965. Alhoewel die reaksie spesiespesifiek was, het die meerderheid van die plantspesies hulle voortplanting aanvang aansienlik vertraag gedurende 2007 in vergelyking met 1965. Hoe ookal, dis nie duidelik of die waargeneemde spesie reaksie was as gevolg van die nou droër en warmer Marion Eiland klimaat of deur teenstrydighede in verslagewing gedurende die vroëre studies en/of insameling verskille tussen die onlangse en historiese rekords. Daarom moet hierdie resultate met versigtigheid hanteer word. In samevatting, hierdie navorsing voorsien ‘n gedetaileerde fenologiese dinamieka rekord vir vaatplantspesies op die eiland. Oor tyd kan hierdie rekords gebruik word as basis vir monitering en modellering van die impak van klimaat.

Thesis (MScConEcol)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The fire-prone mediterranean-type climate regions of the world are immensely biodiverse. Changes in fire frequency due to anthropogenic ignitions and climate change are one of the factors threatening the plant diversity of these regions. Many postfire regeneration studies have focused on seedling recruitment, whereas much can still be learned about regeneration through resprouting. This project focused on resprouters after a fire and assessed if there are differences between the obligate (OS) and facultative (FS) resprouting life history types. OS species have to resprout after fire, as their seeds are not fire resistant and seedling recruitment takes place in fire-free periods, whereas FS species have the ability to resprout and recruit seedlings after a fire. My analyses found a significant difference in postfire resprout success between OS species and FS species, supporting the division of woody resprouting shrubs into these two life history types. OS species had minimal fire-related mortality and this was related to their ability to resprout early and vigorously after fire. OS species had no postfire mortality, which points to traits that enable them to endure the hot and dry summer months. The FS species varied in their response to fire and had greater fire induced mortality than the OS species. Postfire mortality (post-sprouting) was also greater compared to OS species, especially towards the end of the long dry summer suggesting a link to water stress. A postfire seedling survey of target FS, OS and non-sprouters (NS), revealed that NS species had seedling/adult ratios that were orders of magnitude higher ranging between 40-200 seedlings per adult against less than 1-10 seedlings per adults for FS, with OS species recruiting no seedlings directly postfire, as is consistent with their life history type. Although the NS species do not sprout and the FS species had some mortality, the population was at or above replacement two-year postfire on account of seedling recruitment. OS species maintained their pre-fire population by successfully resprouting and by experiencing almost no postfire mortality. These results provide strong justification for grouping woody resprouters into OS and FS species in future studies seeking to understand the underlying differences in postfire recovery. Postfire flowering phenology was also observed during the two year study period. Geophytes, mostly belonging to the Iridaceae and Orchidaceae were overrepresented within the first year postfire, many displaying fire-stimulated flowering. This suggests that some geophytes limit their reproductive cycle to the immediate postfire environment, when nutrients and light are abundant. Smaller resprouting shrubs generally flowered earlier than larger resprouting shrubs. Many non-sprouting shrubs did not reach maturity within the study period and those that did mostly belonged to the Fabaceae and Asteraceae families. This study added 71 species to the existing Paarl Mountain species list, including eight new red listed species, highlighting the importance of early postfire field surveys. / AFRIKAANSE OPSOMMING: Veldbrande is ‘n natuurlike verskynsel in die meditereense klimaatstreke van die wereld. Hierdie areas is ook bekend vir hulle ryk biodiversiteit. Veranderinge in die vuur frekwensie as gevolg van klimaatsverandering en veldbrande wat deur mense veroorsaak word, bedreig die plantdiversiteit van hierdie streke. Vorige veldbrandstudies het meestal gefokus op saailinge en daar bestaan ‘n groot leemte om regenerasie deur herspruiting beter te verstaan. Hierdie navorsingsprojek fokus op herspruiting van fynbos plante as ‘n oorlewingstrategie na ‘n veldbrand. Spesifiek word daar gekyk na verskille tussen verpligte (VH) en nie-verpligte (fakultatiewe) herspruiters (FH). VH spesies moet herspruit na vuur om hulle populasie stabiel te hou, aangesien hulle saad nie vuurbestand is nie. FH spesies het die vermoë om te herspruit sowel as saailinge te werf na ‘n brand. Die studie bevindinge dui op betekenisvolle verskille tussen hierdie twee lewensgeskiedenistipes en regverdig die groepering van houtagtige herspruiter spesies as VH of FH. VH het minimale mortaliteit getoon na die veldbrand. Bykans alle plante het vinnig en kragtig herspruit. VH besit ook eienskappe wat hulle in staat stel om die warm, droeë somers te oorleef. Die oorlewing van FH was wisselvallig, met mortaliteit as gevolg van direkte vuurskade en verdere mortaliteit gedurende die lang somermaande, moonlik as gevolg van water stress. ‘n Saailingstudie van VH, FH en ook nie-spruiters (NS) het getoon dat die saailing/volwasse verhoudings van NS ordes hoër is as die van FH. VH het geen saailinge direk na die vuur geproduseer nie. Twee jaar na die vuur was FH en NS saailing getalle steeds heelwat meer as die aantal volwasse plante wat dood is in die veldbrand. VH het hul populasie stabiliteit gehandhaaf deurdat alle volwasse plante suksesvol herspruit het. Hierdie bevindinge regverdig die verdeling van herspruitende fynbos spesies as VH of FH. Verdere studies is belangrik om die onderliggende ekofisiologiese verskille tussen die twee lewensgeskiedenistipes beter te verstaan. Die blompatrone van verskillende spesies is ook aangeteken tydens die tweejaar studieperiode. Bolplante, veral in die iris- (Iridaceae) en orgidee (Orchidaceae) families het oorheers gedurende die eerste jaar na die brand, aanduidend van ‘n vuur-gestimuleerde blompatroon. Sommige bolplante mag hul voorplantingssiklus beperk tot die periode direk na veldbrand, terwyl daar genoeg lig is en die grond verryk is met voedingsstowwe. Kleiner herspruitende struike het in die algemeen vroeër geblom as groter struike. Nieherspruitende struike het meestal nie seksuele volwassenheid bereik binne twee jaar na die veldbrand nie, buiten sommige in die ertjie- (Fabaceae) en asterfamilies (Asteraceae). Die studie het 71 nuwe spesies tot die bestaande Paarlberg spesielys gevoeg, waarvan agt rooidataspesies was, wat die waarde van plantopnames direk na ‘n veldbrand beklemtoon.