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Alien plant invasions are a major threat to biodiversity and ecosystem functioning in South Africa's Cape Floristic Region (CFR). Large-scale government-funded management initiatives are underway to reduce the extent of invasions in this region. Among the many challenges are the huge spatial extent of the invasions and difficulties in coordinating management efforts across large areas of invaded land in private ownership. Very little information is available on the success of privately-funded alien plant control initiatives. This study investigated the effectiveness of one large project in reducing alien plant cover, the challenges faced and the costs associated with long-term clearing operations on privatelyowned land in the CFR. Results for the study area (Vergelegen) show that the cover of dense invasive plant stands declined by 70% over 10 years since management operations began, but that operations cost 3.6 times more than was originally estimated (ZAR 43.6 vs 12.19 million, respectively). The challenges associated with managing invasive alien plants (IAPs) on private land are very similar to those faced on state-owned land, with the efficiency of management being constrained by multiple interacting environmental and socio-economic factors. However some success in managing IAPs can be achieved by adhering to basic principles, including careful planning with clear achievable goals in mind, a commitment to stable long-term funding and regular monitoring. Most private land owners cannot afford the substantial investment of resources that would be required to clear large stands of IAPs and to ensure that cleared areas are maintained to prevent re-invasion, and finding ways to fund this remains a challenge. [ABSTRACT FROM AUTHOR]

The Global Biodiversity Information Facility (GBIF) is at the moment one of the largest and most widely used biodiversity databases. Nevertheless, there are still some limitations, e.g. in terms of plant species status (native vs. non-native) and geographic resolution of records. At the same time, it is well known that alien plant invasions in inland freshwaters can alter community structure, ecosystem functions and services with significant negative impacts on biodiversity and human activities. We assessed if the GBIF database has a geospatial homogeneous information for native and non-native aquatic plant species for South America and whether or not literature resources not yet digitalized (floras, checklists and other papers) could provide additional information. We selected a set of 40 native and 40 non-native aquatic species. These 80 species included a sub-set of 40 alien species previously evaluated with the USAqWRA scheme (US Aquatic Weed Risk Assessment). Species with non-reliable identification, duplicates of the same collection, records poorly georeferenced were removed from the dataset. New records were manually compiled through classical literature research. All the georeferenced records (GBIF + literature) were used for the mapping and the comparative analysis. As a result, we can conclude that the two datasets provide quite significantly different information and the combination of the two offers new information that would not exist in a single data source. Nevertheless, a careful [ABSTRACT FROM AUTHOR]

Japanese barberry (Berberis thunbergii DC) is a non-native shrub currently found in 31 states and four Canadian provinces. We examined the effectiveness of directed heating using 400,000 BTU backpack propane torches to control Japanese barberry infestations at two study areas in southern Connecticut. Each study area had eight 50-m × 50-m plots. Treatment combinations included a pre-leafout or post-leafout initial treatment with propane torches to reduce the size of established clumps and an early (late June), mid (early July), or late (late July) follow-up treatment to kill sprouts that developed from surviving root crowns. All treatment combinations were equally effective and reduced barberry abundance (a surrogate for cover) from 31% prior to treatment to only 0.5% the following autumn (i.e., a 98% reduction). All treatment combinations were also equally effective in reducing the size of surviving barberry to an average of only 11 cm compared with 74 cm for untreated clumps. Estimated labor costs using propane torches for both initial and follow-up treatment was 2.5 hr/ha for every 1% pretreatment abundance (e.g., 25 hr for a 1-ha stand with 10% abundance). Because timing of initial treatments (pre-leafout vs. post-leafout) and follow-up treatment (early, mid, late) were equally effective in reducing Japanese barberry abundance and height of surviving stems, initial treatments can be completed from March-June and follow-up treatments can be completed from June-August in southern New England. For habitat restoration projects on properties where herbicide use is restricted, directed heating with propane torches provides a non-chemical alternative that can effectively control invasive Japanese barberry. [ABSTRACT FROM AUTHOR]

1. Although habitat fragmentation and species invasions are widely recognized threats to biodiversity, few empirical studies have examined both threats together. Here we test the hypothesis that habitat fragmentation may limit the spread of invasive species across landscapes. 2. In central Texas, patches of herbaceous vegetation become increasingly fragmented (e.g. smaller and more isolated) as landscapes undergo woody plant encroachment. However, during this process, fragmentation and loss of herbaceous habitat are not completely correlated, which allowed us to separate the effects of fragmentation from the effects of habitat loss. 3. At three sites in central Texas, we recorded the occurrence of the invasive bunchgrass Bothriochloa ischaemum in randomly-located plots in herbaceous patches. We measured fragmentation of the herbaceous habitat around these plots at five scales, using aerial photographs. 4. Bothriochloa ischaemum occurrence was significantly negatively related to most aspects of fragmentation. These negative relationships were stronger after the effects of habitat loss were removed from the effects of fragmentation per se. 5. The strength of the negative relationship between B. ischaemum occurrence and fragmentation varied among sites, probably reflecting the influence of grazing and other management practices. 6. Synthesis and applications. Our results indicate that fragmentation, separated from habitat loss, can have positive as well as negative conservation effects. Fragmentation, if wisely used, could be a useful tool in the management of invasive plant species like B. ischaemum. Increasing the degree of habitat fragmentation may slow the spread of invasive species across landscapes. [ABSTRACT FROM AUTHOR]

1. Matrix population models are widely used to describe population dynamics, conduct population viability analyses and derive management recommendations for plant populations. For endangered or invasive species, management decisions are often based on small demographic data sets. Hence, there is a need for population models which accurately assess population performance from such small data sets. 2. We used demographic data on two perennial herbs with different life histories to compare the accuracy and precision of the traditional matrix population model and the recently developed integral projection model (IPM) in relation to the amount of data. 3. For large data sets both matrix models and IPMs produced identical estimates of population growth rate (λ). However, for small data sets containing fewer than 300 individuals, IPMs often produced smaller bias and variance for λ than matrix models despite different matrix structures and sampling techniques used to construct the matrix population models. 4. Synthesis and applications. Our results suggest that the smaller bias and variance of λ estimates make IPMs preferable to matrix population models for small demographic data sets with a few hundred individuals. These results are likely to be applicable to a wide range of herbaceous, perennial plant species where demographic fate can be modeled as a function of a continuous state variable such as size. We recommend the use of IPMs to assess population performance and management strategies particularly for endangered or invasive perennial herbs where little demographic data are available. [ABSTRACT FROM AUTHOR]