Biology subjects

Ignacio C Fernandez

Publications and source records attributed to Ignacio C Fernandez.

3 recordsLinked to original sources

bioRxiv2016

MaxEnt′s parameter configuration and small samples: Are we paying attention to recommendations?

Environmental niche modeling (ENM) is commonly used to develop probabilistic maps of species distribution. Among available ENM techniques, MaxEnt has become one of the most popular tools for modeling species distribution, with hundreds of peer-reviewed articles published each year. MaxEnts popularity is mainly due to the use of a graphical interface and automatic parameter configuration capabilities. However, recent studies have shown that using the default automatic configuration may not be always appropriate because it can produce non-optimal models; particularly when dealing with a small number of species presence points. Thus, the recommendation is to evaluate the best potential combination of parameters (feature classes and regularization multiplier) to select the most appropriate model. In this work we reviewed 244 articles from 142 journals between 2013 and 2015 to assess whether researchers are following recommendations to avoid using the default parameter configuration when dealing with small sample sizes, or if they are using MaxEnt as a \"black box tool\". Our results show that in only 16% of analyzed articles authors evaluated best feature classes, in 6.9% evaluated best regularization multipliers, and in a meager 3.7% evaluated simultaneously both parameters before producing the definitive distribution model. These results are worrying, because publications are potentially reporting over-complex or over-simplistic models that can undermine the applicability of their results. Of particular importance are studies used to inform policy making. Therefore, researchers, practitioners, reviewers and editors need to be very judicious when dealing with MaxEnt, particularly when the modelling process is based on small sample sizes.

Ecology↗

bioRxiv2015

Prioritization of sites for plant species restoration in the Chilean Biodiversity Hotspot: A spatial multi-criteria decision analysis approach

Various initiatives to identify global priority areas for conservation have been developed over the last 20 years (e.g. Biodiversity Hotspots). However, translating this information to actionable local scales has proven to be a major task, highlighting the necessity of efforts to bridge the global-scale priority areas with local-based conservation actions. Furthermore, as these global priority areas are increasingly threatened by climate change and by the loss and alteration of their natural habitats, developing additional efforts to identify priority areas for restoration activities is becoming an urgent task. In this study we used a Spatial Multi-Criteria Decision Analysis (SMCDA) approach to help optimize the selection of sites for restoration initiatives of two endemic threatened flora species of the \"Chilean Winter Rainfall-Valdivian Forest\" Hotspot. Our approach takes advantage of freely GIS software, niche modeling tools, and available geospatial databases, in an effort to provide an affordable methodology to bridge global-scale priority areas with local actionable restoration scales. We used a set of weighting scenarios to evaluate the potential effects of short-term vs long-term planning perspective in prioritization results. The generated SMCDA was helpful for evaluating, identifying and prioritizing best suitable areas for restoration of the assessed species. The method proved to be simple, transparent, cost effective and flexible enough to be easily replicable on different ecosystems. This approach could be useful for prioritizing regional-scale areas for species restoration in Chile, as well as in other countries with restricted budgets for conservation efforts.

Ecology↗

bioRxiv2015

Combining niche modelling, land use-change, and genetic information to assess the conservation status of Pouteria splendens populations in Central Chile

BackgroundPouteria splendens (lucumo chileno) is an endemic shrub to the coastal areas of Central Chile classified as Endangered and Rare by the Chilean threatened species list, but as Lower Risk (LR) by IUCN. Based in historical records some authors have hypothesized that P. splendens originally formed a large metapopulation, but due to habitat loss and fragmentation these populations have been reduced to two main areas separated by 100 km, neither of both currently protected by the Chilean system of protected areas. Knowledge about this species is scarce and no studies have provided evidence to support the large metapopulation hypothesis. This gap of knowledge limits our availability to gauge the real urgency to conserve remaining P. splendens populations, which can generate tragic consequences in light of the increasing land-use change and climatic change that are facing these populations. In this study we combined niche modelling, land-use information, future climatic scenarios, and conservation genetics techniques, to test the hypothesis of a potential original large metapopulation, evaluate the role of land-use change in population decline, assess the threats this species may face in the future, and combine the generated information to re-assess its conservation status using the IUCN criteria.\n\nResultsOur results show that locations with P. splendens are fewer than described in the literature. Results from the niche modelling and genetic analyses support the hypothesis of an originally large metapopulation that was recently reduced and fragmented by anthropogenic land-use change. Future climate change could increase the range of suitable habitats for P. splendens towards inland areas; however the high level of fragmentation of these new areas is expected to preclude colonization processes.\n\nConclusionsBased on our results we recommend urgent actions towards the conservation of this species, including (1) re-evaluating its current IUCN conservation status and reclassifying it as Endangered (EN), and (2) take immediate actions to develop strategies that effectively protect the remaining populations.

Ecology↗