Cranes in the marsh

I spent a lot of time on I-95 this Thanksgiving weekend. A lot of time. However, in the throng of grumpy travellers, there was a happy sight for which I was thankful. And this small delight came when I least expected it - when traversing the badly degraded Hackensack Meadowlands, which is generally, for me, a mournful crossing. The sight: cranes on the marsh. Not avian cranes...construction cranes!

There is a massive restoration taking place on the Richard Kane Wetlands, where the Meadowlands Conservation Trust and EarthMark Mitigation Services are removing invasive Phragmites, reconnecting tidal creeks, and planting salt marsh grasses on >200 acres of brackish marsh. The area is large - the photo below (a good one, no? I was pleased with it.) does not capture the full area being restored. This work is financed as a "mitigation bank" - companies or agents (in this case, mostly transportation agencies) degrading or destroying wetlands in other places compensate by paying for the restoration improvements. It is positive that this approach can fund truly large scale restoration efforts. However, these positive advances come at the cost of continued wetland degradation and destruction elsewhere. Is this tradeoff the best option for funding restorations?

marsh restoration in the Gulf of Mexico

Here is a photo of the type of wave protection being put on salt marsh restorations in the Gulf of Mexico, like the ones referred to in Rusty Feagin's comment. Thanks for the photo, Rusty!

Mangrove restoration suggestion

My collaborator, Brian Silliman, and I published a comment this month in the British scientific journal Ambio about incorporating into mangrove restoration design plans the natural capacity of wetland plants to reduce environmental stress for them and their neighbors . Here is an excerpt (references omitted):

Using Facilitation Theory to Enhance Mangrove Restoration

Most mangrove restorations around the world, including the Philippines example, plant mangroves as single seedlings, evenly spaced, in rows. This configuration is based on the assumption that competition among seedlings needs to be minimized to foster establishment and growth. Thus seedlings need to be spaced well away from each other to maximize light availability and minimize competition between neighbors. However, whereas light availability can be a limiting factor at later stages in mangrove forest development, the limiting growth factors at the initial stages of mangrove establishment are edaphic stressors, such as low redox potential and high soil salinity, as recognized by the Samson and Rollon. Because coastal wetland plants engineer the substrate to ameliorate these harmful conditions, an effect that increases with wetland plant density, seedlings are likely to exhibit positive, not negative, density dependence because of the facilitative effects of neighbors on ameliorating anoxic soil conditions.

Ecological theory and wetland experiments both predict that mangrove seedlings have a far better chance of survival if they are planted in clusters of several seedlings rather than plantation style. Planting seedlings in clusters will likely allow the necessary positive feedbacks to take root in the absence of adult plant roots or pneumatophores. For example, a black mangrove restoration in Mexico that planted five-seedling clusters resulted in notably high survival of planted seedlings (74%) after 4 years, despite being planted in a mudflat environment. Mangrove seedlings frequently suffer high rates of mortality, and clustered or redundant plantings allow surviving seedlings to compensate for lost neighbors. Nurse plants, which can serve the same purpose in a restoration as seedling clusters, promoting the facilitative species interactions that ameliorate abiotic stress, have also been found to improve mangrove restoration success. Higher plant densities have also been found to reduce herbivory on susceptible, young plants in other saline wetland environments.

10,000 lakes...in Florida?

There has been debate about the value of secondary forest, and I have read similar debate about the equivalency of restored ecosystems to their natural counterparts. But what about another common semi-natural system, artificial lakes?

My grandmother lives in Florida in a condo development with an artificial lake behind her building. I’ve observed that, in Florida, there are many, many grandmothers who live adjacent to many, many artificial lakes. I’m not sure if the lakes are usually stocked with fish or not, but I’ve seen a good deal of birds around these lakes, such as the pictured group of white ibises, Eudocimus albus, and the cattle egret, Bubulcus ibis, below.

The abundance of waterbirds suggests some ecosystem value from artificial lakes. Some ecologists argue that birds are good indicators of community health (though probably not these birds, which are quite common in disturbed systems).

However, these lakes must be quite eutrophied. They are generally adjacent to well-trimmed lawns and golf courses that I presume are well-fertilized. A close-up photo of the lakewater nearshore shows a thick algal slime in the lake. To sum up: These artificial lakes are probably crappy habitat, but at least there are a lot of them…