Predator-free space, functional responses and invasions.

1. Predator–prey interactions are mediated by the structural complexity of habitats, but disentangling the many facets of structure that contribute to this mediation remains elusive. In a world replete with altered landscapes and biological invasions, determining how structure mediates the interactions between predators and novel prey will contribute to our understanding of invasions and predator–prey dynamics in general.
2. Here, using simplified experimental arenas, we manipulate predator-free space, whilst holding surface area and volume constant, to quantify the effects on predator–prey interactions between two resident gammarid predators and an invasive prey, the Ponto-Caspian corophiid Chelicorophium curvispinum.
3. Systematically increasing predator-free space alters the functional responses (the relationship between prey density and consumption rate) of the amphipod predators by reducing attack rates and lengthening handling times. Crucially, functional response shape also changes subtly from destabilizing Type II towards stabilizing Type III, such that small increases in predator-free space to result in significant reductions in prey consumption at low prey densities.
4. Habitats with superficially similar structural complexity can have considerably divergent consequences for prey population stability in general and, particularly, for invasive prey establishing at low densities in novel habitats.

Forecasting invasions: resource use by mussels informs invasion patterns along the South African coast

Invasive species are often more able to rapidly and efficiently utilise resources than natives, and comparing per capita resource use at different resource densities among invaders and trophically analogous natives could allow for reliable predictions of invasiveness. In South Africa, invasion by the Mediterranean mussel Mytilus galloprovincialis has transformed wave-exposed shores, negatively affecting native mussel species. Currently, South Africa is experiencing a second mussel invasion with the recent detection of the South American Semimytilus algosus. We tested per capita uptake of an algal resource by invading M. galloprovincialis, S. algosus, and the native Aulacomya atra at different algal concentrations and temperatures, representing the west and south coasts of South Africa, to examine whether their per capita resource use could be a predictor of their spread and subsequent invasiveness. Regardless of temperature, M. galloprovincialis was the most efficient consumer, significantly reducing algal cells compared to the other species when the resource was presented in both low and high starting densities. Furthermore, these findings aligned with a greater biomass of M. galloprovincialis on the shore in comparison with the other species. Resource use by the new invader S. algosus was dependent on the density of resource and, although this species was efficient at low algal concentrations at cooler temperatures, this pattern broke down at higher algal densities. This was once more reflected in lower biomass in surveys of this species along the cool west coast. We therefore forecast that S. algosus will be become established along the south coast; however, we also predict that M. galloprovincialis will maintain dominance on these shores.

Broadside reporting the Fenian Invasion of Canada, June 2, 1866

The Fenians were a group intent on securing Irish independence from England. The movement had its origins in Ireland in1857, under the leadership of James Stephens, with the assistance of John O'Mahony, an American who had raised funds for the cause. The American branch of this movement was especially successful, having raised $500 000 and enlisting about 10 000 American Civil War veterans. The group split into two separate factions, one desiring an invasion of Canada and the other preferring an uprising in Ireland. It soon became apparent that an uprising in Ireland was not imminent, and a decision was made to invade Canada. In April, 1866, a raid was launched against New Brunswick. It proved unsuccessful, and another raid was attempted on June 1, 1866, this time in Ridgeway, near Fort Erie, Ontario. The Canadian militiamen were defeated, but the Fenians subsequently withdrew. A third incident occurred on June 7, this time at Missisquoi Bay in Quebec, when the Fenians crossed the border, remained there for 2 days, and withdrew. A failed uprising in Ireland in 1867 signaled the demise of the movement. The Fenian threat helped to promote a sense of union among Canadians and provided an incentive for Confederation.

Broadside Reporting the Fenian Invasion of Canada, June 3 1866

The collection consists of 6 broadsides reporting the events of the Fenian invasion of Canada on June 2 and 3, 1866. This broadside is titled Globe Extra and is from the evening of June 3rd, 1866. Some of the headings include: "Numerous Fenian Prisoners in our Hands", "All Quiet at Sarnia!" and "Further from Montreal! Troops Leaving for the Front".

Broadside Reporting the Fenian Invasion of Canada, June 4 1866

The collection consists of 6 broadsides reporting the events of the Fenian invasion of Canada on June 2 and 3, 1866. Three of the broadsides are titled Leader Extra, two are titled Globe Extra, and the last is titled News Extra. This one is titled Leader Extra and leads with the heading "Fenian Prisoners Twenty-One of them in Toronto Jail. Also included, "Latest American Reports: Interesting News from the East".

Broadside Reporting the Fenian Invasion, June 2 1866

The collection consists of 6 broadsides reporting the events of the Fenian invasion of Canada on June 2 and 3, 1866. Three of the broadsides are titled Leader Extra, two are titled Globe Extra, and the last is titled News Extra. This one is titled Leader Extra and begins with 2nd edition and ends with 8th edition. The headings include: "First Engagement: Our Gallant Volunteers foremost in the Attack", "Victory! Victory!", "Fenian Leader Shot", Battle at Fort Erie".

Broadside Reporting the Fenian Invasion, June 3 1866

The collection consists of 6 broadsides reporting the events of the Fenian invasion of Canada on June 2 and 3, 1866. Three of the broadsides are titled Leader Extra, two are titled Globe Extra, and the last is titled News Extra. This one is titled "Globe Extra!" and headings include "Colonel Peacock's Force", "Col. Lowry Joins Col. Peacock with Reinforcements", "Colonel Dennis' Skirmish", "Colonel Booker's Skirmish!", "Fenian Movements at Ogdensburg", "Tereatened Raid at St. Albans", "Preparations at Cornwall!", "Latest! Bad News! The Fenians Escaped! The Whole Horde Fled Across the River."