Background : Old fields are abandoned agricultural areas that are undergoing secondary succession. A variety of factors influence the assembly, invasibility, and species turnover during secondary succession in old fields. Old fields are important ecological research locations as an increasing amount of agricultural land is abandoned worldwide. Objectives : 1) To determine if exotic and native "invaders" display differences in invasion success in an old field, and 2) To observe how native and exotic species abundances change over the course of secondary succession under predictable disturbance regimes and resource levels with regards to the Core-Satellite Species (CSS) hypothesis. Methods : An old field located in southern Illinois subject to three levels of fertilization (control, annually fertilized, and fertilized every 5 years) crossed with three levels of mowing treatments (control, spring mowed, and spring/fall mowed) established in 1996 was used to test objectives Seedlings of C3 grasses (native and exotic) were planted within one fertilizer treatment to compare invasion success. Species composition data (species occurrence and abundance at three heights) in all blocks were previously collected from 1996 to 2002 and the sample plots were resampled in 2013. Species sampled in 2013 were assigned to core or satellite categories per the CSS hypothesis. Results : Invading exotic seedlings had higher survivorship than invading native seedlings from the same functional group within the same fertilizer level, and added fertilizer increased seedling survivorship. The number of core and satellite species varied early after experiment establishment in 1996 but has since leveled off, and the ratio of exotic to native species cover at heights <1m ratio was affected by an interaction between mowing treatment and time. The species occupancy distribution of all species in 2013 was not bimodally distributed, but the occupancy distribution of exotic species in 2013 was bimodally distributed.The community composition of the plots varied among blocks, but was affected by an interaction between fertilizer treatment and mowing. Conclusions : Exotic invading grass seedlings in a successional community were relatively more successful than native invading grass seedlings. However, overall survivorship of all invading grass seedlings was low, a typical finding in grasslands. The identity of core and satellite species continued to fluctuate through time following 17 years of secondary succession. Resource availability and disturbance regime affects on community composition throughout secondary succession, and may result in many alternative stable states. This research supports the `CSS' and `parallel dynamics' hypotheses and indicates that presence of exotic species within a community does not necessarily facilitate invasion by new exotic species.

Risk and tracking error budgeting was originally adopted by large institutional investors, including pension funds, plan sponsors, foundations, and endowments. More recently, risk and tracking error budgeting have gained popularity among financial advisors, multi-managers, fund of funds managers, high net worth individuals as well as retail investors. These techniques contribute to the portfolio optimisation process by limiting the extent to which a portfolio can deviate from its benchmark with regards to risk and tracking error. This is an ambitious paper that attempts to determine the optimal strategy to practically implement risk and tracking error budgeting as a portfolio optimisation technique in South Africa. This study attempts to bridge the gap between active, passive, and smart-beta investment management styles by introducing a low-cost portfolio construction technique, for core-satellite portfolio management, which contributes to the risk and tracking error budgeting process. Core-satellite portfolios are designed to expose the portfolio to a low-cost primary “core” consisting of passive and enhanced index funds, thus systematic risk “beta”, limiting the tracking error of the portfolio. The secondary “satellite” component is allocated to active and smart-beta managers to exploit expected excess return “alpha”. The primary aim of this research is to construct a rule-based product range of core-satellite portfolios called “replica portfolios”. The product range builds on the foundation of the Association for Savings &amp; Investments South Africa (ASISA) framework. The study identifies three “target portfolios” from ASISA's framework, namely (1) High Risk: SA General Equity, (2) Medium Risk: SA Multi-Asset High Equity and (3) Low Risk: SA Multi-Asset Low Equity. Through this framework, active managers from each category are shortlisted using a Sharpe and Information Ratio filter. A secondary filtering technique, namely Returns Based Style Analysis (RBSA) is used to determine the style, R-squared and alpha-generating ability of active managers versus the passive asset classes and style indices they seek to replicate. Applying Euler's theorem for homogenous functions, we decompose the risk of the coresatellite portfolio into the risk contributed by each of its components. The primary mandate of the core-satellite portfolios in the product range is to allocate risk and tracking error efficiently across several investment management styles and asset classes in order to maximise returns while remaining within the specified risk parameters. iii The results highlighted that active managers, after fees, predominantly failed to outperform their benchmarks and passive building blocks, as identified through RBSA over the sample period (October 2009 – September 2019). However, only a small number of active managers generated superior risk-adjusted returns and were included in the core-satellite range of products. This study recommends to investors that they exploit the “hot-hands effect” by investing in specialised, benchmark agnostic active managers who consistently produce superior risk-adjusted returns. By blending active, passive and smart-beta strategies, investors are exposed to less total risk, less risk per holding and a lower tracking error. The three coresatellite portfolios developed in this study generated absolute and risk-adjusted returns that are more significant than their active and passive counterparts. Fee arbitrage was derived through the range of core-satellite products, resulting in tangible alpha over the sample period. The study encourages investors to use smart-beta strategies alongside active and passive funds since it improves Sharpe and Information ratios while enhancing the original portfolio's characteristics.