Method
Contenido
La práctica de la restauración ecológica consiste en inducir una mínima perturbación (o secuencia de perturbaciones) en el espacio degradado con el fin de desencadenar un proceso espontáneo de reconfiguración del sistema en la dirección deseada. No existen recetas extrapolables. Es decir, lo que resulta exitoso en un enclave puede ser un clamoroso fracaso en otro lugar de características aparentemente semejantes. Es por ello que cada proyecto de restauración ecológica se inicia con un diagnóstico ecológico específico e individualizado. No existen, tampoco, técnicas específicas de restauración ecológica, y así la solución propuesta puede ir desde la reconfiguración del relieve hasta simplemente el esparcimiento de piedras, desde la plantación de ejemplares de especies arbóreas hasta la tala y destoconado de árboles adultos, desde la siembra a voleo al restablecimiento de las redes de aves dispersoras de frutos y semillas. Las conclusiones de cada diagnóstico permiten la aplicación de técnicas conocidas o el desarrollo de otras nuevas. En definitiva, el método de la restauración ecológica consiste en gestionar el margen de incertidumbre asociada al manejo de sistemas complejos y dinámicos apoyándose en tres principios fundamentales: el papel del pasado como motor de cambios presentes y futuros, el funcionamiento de los ecosistemas y paisajes a través de las escalas espaciotemporales, y nuestra capacidad como humanos de aprender de la respuesta de los sistemas complejos a manipulaciones experimentales. De esos principios derivan las tres prácticas que conforman el ejercicio de la restauración ecológica: la selección o construcción del referente histórico, el desbloqueo de procesos ecológicos, y la implementación del proyecto siguiendo un modelo de gestión adaptativa.
La reparación de los ecosistemas degradados es una tarea compleja que requiere de una inversión significativa de tiempo, recursos y conocimiento, comprensión de contextos sociales específicos y riesgos, participación adecuada de las partes interesadas y monitoreo adecuado para el manejo adaptativo.[9] Las buenas prácticas de restauración requieren de varios pasos metodológicos, flexibles según el ecosistema que se quiera restaurar. Los Estándares reconocen que un diseño apropiado requiere:.
- Conocer y analizar el ecosistema a restaurar, tanto en su biodiversidad como en funcionamiento. Se sugiere involucrar a todas las partes interesadas en la restauración de un determinado sitio o ecosistema (sector académico, ciudadanos, sector gubernamental, ONGs, etc) para utilizar distintos tipos de conocimientos (cultural, académico, legal, etc.).
- Analizar el nivel de degradación presente en la zona a restaurar.
- Establecer el ecosistema de referencia (nativo) y verificar sus atributos para determinar las actividades a realizar, las variables o indicadores a medir para luego poder monitorear y estimar el grado de restauración logrado en el tiempo.
- Pensar el potencial de restauración en el contexto al que se quiere llegar en cada caso, tratando de buscar el nivel más alto de recuperación. Revisar las posibilidades, como reformas o mejoras del ecosistema a restaurar.
- Fijar objetivos y metas a alcanzar y proponer variables o indicadores a medir para estimar el éxito de la restauración o del aspecto a mejorar.
- Una vez que haya determinado el nivel de degradación, el estado de riesgo ecológico y las necesidades de la biodiversidad, se podrá comenzar a identificar y priorizar las áreas de restauración.
- Calcule la importancia relativa que le otorgará al secuestro de carbono, la biodiversidad y el costo-efectividad en la priorización de las áreas de restauración.
Historical reference
The goal of ecological restoration is not to return to the past. It is not recovering the original situation. Simply because going back to the past is thermodynamically impossible and any severe environmental degradation entails an irreversible net loss. However, what happened in the past remains, at least partially, encoded and stored in the structure and functioning of ecosystems and landscapes. This fraction of remaining information is called 'ecological memory'.[10] Part of this memory can persist latently, and be expressed or activated in the future, and part persists in active processes that originated in the past and are projected into the future.
Ecological memory is stored in the climate, in the relief, in the soil, and in communities of organisms, including human beings. This memory is the historical component of the resilience "Resilience (ecology)") of ecosystems. From this perspective, degradation implies a local loss of memory and the objective of ecological restoration would be to recover and induce the expression of this lost ecological memory in order to offer coherent and founded solutions to current problems and demands. In practice, the restorer orders and reconstructs with the vestiges of ecological memory the sequence of configurations that the degraded space has experienced throughout its history. This sequence constitutes what is known as "ecological trajectory" of the affected ecosystems. The restorer must, then, contrast the ecological trajectory with the current social demand of the inhabitants and social agents related to the space to be restored. Finally, from this contrast, the target configuration must be obtained, called 'historical reference', whose interest lies in serving as a guide to guide the design and execution of the technical solutions from the drafting phase to the monitoring phase of the restoration project.
Critical ecological processes
Severely degraded spaces do not recover spontaneously.[12][13] The ecological restorer intervenes in these environments by unblocking critical ecological processes with the intention that the system after the action evolves spontaneously in the desired direction. Thus, the restorer's strategy is not to impose a finished solution, but rather it is always developed under the maxim: "let the system do its job". Maxim initially stated in the context of the ecological restoration of riverbanks as "let the river do its work".[14] In this context, an ecological process is understood as any change - or set of changes - that takes place within the ecosystem.[15] These changes interact with the ecosystem structure, that is, with the elements that form the current architecture of the ecosystem, to generate the functions of the ecosystems.[2] The changes that affect molecules are nested in those that affect cells, and these in turn in the changes that affect tissues, and so on in organs, individuals, communities, ecosystems, landscapes, regions, etc. In general, these processes, or nested sets of changes, can be grouped into four blocks: erosion and soil stability, water flows and distribution, nutrient retention and recycling, and energy capture and transfer.[16] But for the purposes of ecological diagnosis it is much more explicit to group the processes according to their role in the ecosystem: triggering, transfer, reserve flows, pulses, losses and gains.[17] This model facilitates the 'reading' of the landscape and the visualization of the causes of the degradation of the space to be restored.[18].
For example, leaf litter accumulation plays an important role in a restoration process. Higher amounts of leaf litter maintain higher humidity levels, a key factor for plant establishment. The accumulation process depends on factors such as wind and the species composition of the forest. The litter found in primary forests is more abundant, deeper and contains more moisture than in secondary forests. In turn, the level of leaf litter accumulation is a factor that influences the type of fauna present in the soil. It is important to take these technical considerations into account when planning a restoration project.[19].
In the vision of ecological restoration, the idea that unblocking a critical ecological process triggers a sequence of spontaneous changes is supported by the conception of ecological processes as part of an integrated and hierarchical system, in which the levels that occupy a greater spatial extent are also those that reconfigure more slowly.[20] This is why the chances of a specific restoration project generating a more resilient system are greater when intervening on processes that link functions. ecosystems across different spatiotemporal scales.[21] For this reason, it is recommended that before designing the intervention at a local scale, the critical ecological processes are analyzed and contemplated following a zoom-type approach from the coarsest to the finest scales or detail.[22].
Adaptive management
Ecological restoration projects are structured from the perspective of adaptive management to face the challenge of working with complex systems whose degrees of freedom "Degrees of freedom (physics)") exceed our ability to accurately predict their behavior. Adaptive management is an iterative decision-making process aimed at managing the uncertainty associated with the temporal evolution of the restored space. From this vision, the project is not articulated based on deliverables or certifications of executed tasks, but rather in phases, each of which culminates with a decision-making point about how the next phase described in the project should be approached. Decision making is based on the measurement of specific indicators that inform about the functioning of the space to be restored. Using a medical simile, it is about evaluating how the "health" of the system evolves through specific tests, such as the evolution of sediment emission, the organic matter content of the soil, heavy metals in the leachate, or the composition of the plant communities, among many other possibilities to be selected for each case. This decision-making at the end of each phase is supported by the ecological restoration project, which must anticipate the possible responses, models or scenarios that describe the expected evolution of the system. It is evident that, depending on the magnitude of the objectives set and the degree of customer demand, uncertainty can be faced with different degrees of ambition within the adaptive management scheme. The challenge is to find the balance between acquiring new knowledge and shortening the execution time. This compromise between quality and deadlines generates a range of approaches that range from passive adaptive management based on a single model, to active adaptive management based on an experimental approach:.
It is recommended that the development of the ecological restoration project, structured following the adaptive management scheme, incorporates from the beginning the participation of the affected or interested social agents. This valuable contribution can lead to the identification of new sources of uncertainty, the articulation and visualization of alternative configurations of the ecosystem mosaic, and even a better definition of project objectives.