The colonial tunicate Clavelina lepadiformis is a recent invader to the northwest Atlantic and has the potential to cause ecological and economic harm. This paper provides a review of the biological and ecological characteristics of C. lepadiformis, and hypothesizes the likely mechanisms of introduction, establishment and future expansion. The intent of this paper is to provide a consolidated source of information for marine ecosystem managers and provide a starting point for developing a management strategy, should one be desired. Although C. lepadiformis is not currently a management challenge because of the limited range of the invasion in North America; the similarities between C. lepadiformis and other tunicate invaders, and the proximity of incipient populations to boating, shipping, aquaculture, and energy infrastructure suggest future economic burden of this new invader. Other regions such as the west coast of North America and New Zealand may be at risk for invasion by C. lepadiformis.

Aquatic invasive species decrease yields and increase costs in aquaculture operations worldwide. Anecdotal evidence from Prince Edward Island (PEI, Canada) estuaries suggested that recruitment of the non-indigenous solitary tunicate Ciona intestinalis may be lower on aquaculture gear where colonial tunicates (Botryllus schlosseri and Botrylloides violaceus) are already present. We tested this interspecific competition hypothesis by comparing C. intestinalis recruitment on un-fouled settlement plates to those pre-settled with Botryllus schlosseri or Botrylloides violaceus. C. intestinalis occurred on all plates after 2 month, but it was much more abundant (~80% coverage) on unfouled plates than on pre-settled plates (<10% coverage). However, C. intestinalis showed higher individual growth on pre-settled plates than on unfouled plates. High reproductive potential for C. intestinalis appears to result in rapid recruitment to control plates, but this may be impeded on pre-settled plates due to competition for space, negative settlement cues produced by the colonial tunicates, allelopathy or overgrowth.

Invasive alien species (IAS) cause environmental and economical problems. How to effectively manage all IAS at a large area is a challenge. Hypotheses about IAS (such as the “human activity” hypothesis, the “biotic acceptance” and the “biotic resistance”) have been proposed from numerous studies. Here the state of Alabama in USA, widely occupied by IAS, is used as a case study for characterizing the emergent patterns of IAS. The results indicate that most IAS are located in metropolitan areas and in the Black Belt area which is a historical intensive land use area. There are positive relationships between the richness of IAS and the change of human population, the species richness and the number of endangered species, as well as the total road length and farmland area across Alabama. This study partially supports the above three hypotheses and provides a general pattern of local IAS. Based on possible processes related with IAS, some implications for strategically managing local IAS are discussed.

Biological invasions are one of the most pervasive environmental threats to native ecosystems worldwide. The spontaneous spread of saltcedar is a particular threat to biodiversity conservation in arid and semiarid environments. In Argentina, three species belonging to this genus have been recognized as invaders. The aim of the present study was to identify main dispersal vectors and pathways to refine risk analysis and increase our ability to predict new areas at risk of Tamarix establishment. We surveyed and categorized 223 populations, 39% as invasive, 26% as established, 21% as contained and 14% as detected in nature . Dispersion of saltcedar was found to be associated with watercourses and human-driven disturbances; in addition roads were found to be relevant for the introduction of propagules in new environments. Considering the potential impact of saltcedar invasion and that it is an easily wind-dispersed invasive, it is necessary to implement strategies to monitor dispersal pathways and take actions to eliminate invasion foci, particularly in vulnerable and high-conservation value areas.

Invasive alien species, once they made entry into a region or country, often become difficult to eradicate and it appears that they have come to stay. Worse still, their adverse effects on the native biodiversity are enormous and they are considered ecologically harmful. Agricultural and economic losses to invasive species are comparatively high. Mechanical control is expensive and difficult in some terrains; chemical control is also expensive, requires constant application and has its environmental implications, while biological control is mirred with mixed failures and successes. This paper reviewed that economic exploitation of some notorious invasive species in other countries – such as Sudan, Ethiopia, India, Senegal, Mali and the Gambia – and how this had helped reduce the spread of these invasives and at the same time, became source of income to the poor people. It is believed that adopting this concept in Nigeria will create incentives for harvesting invasive species with more commitment, while it is an indirect way of controlling them. Furthermore, harvesting could be labour intensive, thus creating jobs for people, while it provides additional means of income for rural people, which is a key adaptation strategy for climate change.

The nematode endoparasite, Hexametra angusticaecoides Chabaud and Brygoo, is an intestinal and coelomic nematode known only from lizards and snakes. Herein, we provide a list of all known hosts to date, and document a new host, the Madagascar leaf-nosed snake, Langaha madagascariensis Bonnaterre (Lamprophiidae). Because the known paratenic hosts (mosquitos, midges, and cockroaches) of Hexametra angusticaecoides are all extremely common in Florida, as well as Florida having the highest number of established non-native amphibians and reptiles in the entire world, this should be a concern to biologists and conservationists regarding imported animals for the pet trade.