C1 Experimental eradication of minnows from high mountain lakes (HCl3110) using chemical methods

Mechanical methods should be considered the first option whenever a fish eradication action is planned in mountain lakes. However, there are environmental and biological constraints (lake size, habitat complexity, presence of minnows) which limit their applicability and, in this case, alternative methods are needed. The possibility of developing a safe protocol for the use of piscicides is a strategic step to reverse fish invasion effects in mountain lakes.

Action C.1 involves the application of rotenone treatments in three lakes in the Pyrenees. C.1 is an experimental conservation action, explicitly designed to quantify both the efficacy and side effects of rotenone, and will be associated to rigorous monitoring programme (Actions D1-D4).

C2 Non-native fish eradication from high mountain lakes (HCI 3110 and 3130) and tributary streams using non-chemical methods

The efficacy of mechanical eradication has been demonstrated for small to medium-sized lakes containing trout and other salmonids (Alps, Pyrenees and other non-EU mountain ranges) and for small lakes with minnows (Pyrenees). The aim of this action is to extend the applicability of mechanical fish eradication methods to a larger array of lakes (in terms of size and habitat complexity) and to optimize eradication protocols in terms of cost and effort.

Action C.2 will eradicate alien fish from diverse lakes:

• Minnow eradication in 5 lakes in a new geographical context (Alps)
• Experimental minnow eradication in a new ecological context from 4 medium-large lakes (Pyrenees)
• Application of rapid trout eradication protocols in 11 lakes (Alps and Pyrenees)

C3 Selective mowing of hay meadows (HCls 6410 and 6520) to restore their biodiversity and those accompanying mires (HCls 4020* and 7230)

C.3 involves the restoration of biodiversity loss through mowing on two sites in the Pyrenees and the drawing up of a Management Plan aimed at conservation authorities, local and regional administration and protected areas which can be used when dealing with abandoned wet hay meadows.

The conservation action will be based on the combination of mowing, removal of biomass (harvesting) and extensive livestock farming. These practices will be combined to restore the complex mosaic of conditions which promotes diverse and well-structured habitats.

C4 Livestock management and assisted plant migration for restoring natural values in mires, meadows and lakes (HICs 3130, 6230, 6410, 6520, 7110, 7140, 7220, 7230 and 91D0)

Livestock overgrazing causes serious damage in mires. These effects can be reversed by reducing grazing pressures, which can be temporary although, for severely damaged habitats, total livestock exclusion may be necessary.

Under grazing exclusion or reduced pressure, habitats are expected to undergo natural recovery (passive restoration). Additionally, this recovery can be boosted through assisted plan migration.

Action C.4 will also address the problem of disturbance of habitats by hikers and livestock trampling.

Specifically, action C.4 includes 3 sub-actions:

• Passive restoration combining temporary and permanent livestock exclusion in several Spanish and Italian mires.
• Active restoration: assisted plant migration in the most degraded Pyrenean mire areas, transplanting selected structural plant species from the local pool. At the end of the project a Management plan on active restoration through assisted plant migration under overgrazing pressure will be drafted.
• Petrifying spring restoration, preventing the passage of livestock and tourists creating an alternative path and restoring the affected area.

C5 Forest clearcutting for restoring mires (HCIs 6230* 7110*,7230 and 91D0)

Afforestation in mires is accelerating due to land abandonment, together with rising temperatures and longer summer dry spells. Trees in mires increase transpiration and cause drawdown of the water table, and also biodiversity in mires is strongly affected by the shading caused by the tree canopy as it reduces the relative light intensity.

In order to address this situation, clearcutting actions will be undertaken in Action C.5 to enhance the conservation of mires on three Pyrenean sites. On two of the sites the action will be performed by professional brigades and on the third, the clearcutting has been designed as a participative activity (citizen science) involving volunteers.

At the end of the Action, a management plan will be drafted, including best practices in clearcutting under contrasting environmental conditions.