Browsing by Author "Alonso Vega, J. M."

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Exploring the role of access regimes over an economically important intertidal kelp species
    (2021) Gonzalez-Roca, Fernando; Gelcich, Stefan; Perez-Ruzafa, Angel; Alonso Vega, J. M.; Vasquez, Julio A.
    Achieving sustainable use of kelps is key for small-scale fishers' livelihoods and biodiversity. During the last three decades, Chile has implemented different policy approaches to manage kelps. Unfortunately, assessments of the biological impacts of these management regimes have not received the attention they deserve. In this study, we explore biomass, density, size structure and holdfast diameter/stipe length relation of the kelp Lessonia spp., associated to a territorial user rights policy, which grant exclusive access to fishers, and a regional management plan policy which defines control rules in what were historically de facto open access areas. We compare these with marine protected areas where harvesting is banned, thus serving as a benchmark. The study was performed along the coast of two of the main kelp harvesting regions of Chile. The analyses, performed in two time periods, shows that biomass is greater inside areas managed through territorial user rights and in marine protected areas compared to areas where regional management plans have been implemented, which perform in a similar way to open access sites. Enforcement is a key driver of kelp response. Densities of recruits and juveniles are higher in areas where harvesting and gathering are allowed, whilst adult plants have higher density in marine protected areas. In all cases, kelps have become denser after eleven years. The holdfast diameter/stipe length relation provides an indicator of protection efficiency: stricter regulatory measures are related to larger holdfast diameters and shorter stipes. We conclude that, in general, territorial user rights policies and marine protected areas have contributed to the conservation of wild intertidal Lessonia populations. Results highlight the potential of the regional management plans policy to improve kelp management, but it will probably need important adjustments to enhance enforcement and compliance. In addition management innovations such as rotational harvest strategies could provide an important complement which should be further assessed.
  • No Thumbnail Available
    Item
    The importance of having two species instead of one in kelp management: the Lessonia nigrescens species complex
    (2011) Tellier, Florence; Alonso Vega, J. M.; Broitman, Bernardo R.; Vasquez, Julio A.; Valero, Myriam; Faugeron, Sylvain
    Natural resource management requires extensive knowledge of the biology of the organisms and their responses to ecological and anthropogenic processes. While species are commonly used as management units, the presence of cryptic species morphologically indistinguishable, but with different biological characteristics may hinder the design of appropriate management and conservation measures. Thus, correctly assigning individuals to species is of particular importance and challenges current management approaches in seaweeds, which are highly plastic morphologically. After a synthesis of the species definitions, we show an example of the challenges of managing cryptic species with the Chilean kelp Lessonia nigrescens. We review phylogenetic, biological and ecological evidence indicating that this economically important intertidal species is composed of two cryptic species. In the face of increasing global demand for kelp, an intensified impact of harvesting pressure is observed around the region where both cryptic species find their northern and southern edge of their geographic distributions, around 30 S. We recommend special management strategies targeting harvested areas around such range edge populations. Our synthesis highlights the importance of having two species that are ecologically and genetically different. In addition, the cryptic species may diverge in biochemical composition, opening new perspectives for the alginates' industry. The capacity of conservation and management programs to correctly distinguish new species is of particular importance as numerous cryptic species are constantly being discovered in seaweeds, including kelps.