Restoration Project

Centro Interdisciplinario de Ciencias Marinas - Isla Asuncion

Restoration Objective:

The objective of this study was to test whether giant kelp forests in southern Baja California, Mexico could be restored using transplantation of juvenile plants or seeding with sporophylls. This could speed up the recovery of kelp forests, which supply food to important fishery species (e.g. abalone) and raw material for alginate production.

Site Selection Criteria:

The selected site was inhabited by Eisenia arborea, and had rocky substrata, moderate wave action, and was near to a sea lion colony, which may reduce fish grazing on transplanted giant kelp.

Cause Of Decline:

The giant kelp, Macrocystis pyrifera, forms extensive forests in the North Pacific. This kelp forms important marine forests as they provide habitat, have high productivity and support commercial industry. The size of giant kelp forests varies greatly due to environmental disturbances such as El Niño. Kelp forests were devastated in California in the 1982/1983 El Niño and subsequent storms.

Key Reasons For Decline:

Heatwave

Scientific Paper

Restoration techniques for Macrocystis pyrifera (Phaeophyceae) populations at the southern limit of their distribution in Mexico

G. Hernandez-Carmona, O. Garcia, D. Robledo, M. Foster, , Botanica Marina, Vol. 43.https://doi.org/10.1515/BOT.2000.029

Organisation:

Centro Interdisciplinario de Ciencias Marinas

Site Observations:

Observation Date

1st Apr 1997 – 1st Jul 1997

Action Summary:

In April 1997, at least 50 mature reproductive blades per quadrat were collected from adult M. pyrifera and placed in cages. The sporophylls were transported to the experimental site in a wet, cool dark insulated box and placed in the cages according to treatment every month. The seeding technique was tested in a fully orthogonal-block design with three factors with two levels (factors: ± sporophylls addition, ± Eisenia arborea and ± understory algae).

Lessons Learned:

Combining transplanting juveniles with seeding dispersal during spring may result in more effective restoration.

Project Outcomes:

New recruits of M. pyrifera were only found in quadrats that had been seeded with sporophylls, and not in control sites. The concentration of Macrocystis pyrifera sporophytes was particularly high on the cages and on the horizontal edges and flat areas of the concrete base.

Nature of Disturbance:

El Niño conditions caused the mortality of all recruits from seeding quadrats before they reached adulthood.

Key Reasons For Decline:

Heatwave

Area of Restoration (In Square Metres)

0.9

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Juvenile Kelp Count

33100
Transplant Info:
Source:Wild
Costings:
Cost Year:2000
Cost Currency:USD

Observation Date

1st Feb 1987 – 1st Aug 1987

Action Summary:

Juvenile M. pyrifera sporophytes were attached to Eisenia arborea stumps seasonally over a two-year period. After cutting E. arborea stipes, the holdfasts of Macrocystis pyrifera were tied to Eisenia arborea stumps with thick rubber bands.

Lessons Learned:

Combining transplanting juveniles with seeding dispersal during spring may result in more effective restoration.

Project Outcomes:

The first quadrat was set in winter 1988. After 3 months, 41% of transplants survived, while 27% survived until summer 1988. In spring 1988, the second quadrat was transplanted. 7% of transplants only survived to the next season (summer 1988) and 40% survived until winter 1989. The third quadrat was transplanted in summer 1988. Of these, 10% survived to winter of 1989. The remaining transplants survived into autumn 1989 and became adults. At the end of the experiment, all quadrats had a healthy canopy of M. pyrifera covering a total area of 1875 m2.

Key Reasons For Decline:

Heatwave

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Percent Survival

6.3796
%
100
%
Transplant Info:
Adherence Method:Existing Holdfast
Life Stage:Juveniles
Source:Wild
Costings:
Cost Year:2000
Cost Currency:USD
Total Cost:5,500