Lucas B. Fortini

Modeling Hawaiian Ecosystem Degradation due to Invasive Plants under Current and Future Climates

Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with <0.7 niche overlap (Warrens I) and relatively discriminative distributions (Area Under the Curve >0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.

Large-Scale Range Collapse of Hawaiian Forest Birds under Climate Change and the Need 21st Century Conservation Options

Hawaiian forest birds serve as an ideal group to explore the extent of climate change impacts on at-risk species. Avian malaria constrains many remaining Hawaiian forest bird species to high elevations where temperatures are too cool for malaria’s life cycle and its principal mosquito vector. The impact of climate change on Hawaiian forest birds has been a recent focus of Hawaiian conservation biology, and has centered on the links between climate and avian malaria. To elucidate the differential impacts of projected climate shifts on species with known varying niches, disease resistance and tolerance, we use a comprehensive database of species sightings, regional climate projections and ensemble distribution models to project distribution shifts for all Hawaiian forest bird species. We illustrate that, under a likely scenario of continued disease-driven distribution limitation, all 10 species with highly reliable models (mostly narrow-ranged, single-island endemics) are expected to lose >50% of their range by 2100. Of those, three are expected to lose all range and three others are expected to lose >90% of their range. Projected range loss was smaller for several of the more widespread species; however improved data and models are necessary to refine future projections. Like other at-risk species, Hawaiian forest birds have specific habitat requirements that limit the possibility of range expansion for most species, as projected expansion is frequently in areas where forest habitat is presently not available (such as recent lava flows). Given the large projected range losses for all species, protecting high elevation forest alone is not an adequate long-term strategy for many species under climate change. We describe the types of additional conservation actions practitioners will likely need to consider, while providing results to help with such considerations.

Palynological composition of a Lower Cretaceous South American tropical sequence: Climatic implications and diversity comparisons with other latitudes

PREMISE OF THE STUDY Reconstruction of floristic patterns during the early diversification of angiosperms is impeded by the scarce fossil record, especially in tropical latitudes. Here we collected quantitative palynological data from a stratigraphic sequence in tropical South America to provide floristic and climatic insights into such tropical environments during the Early Cretaceous. METHODS We reconstructed the floristic composition of an Aptian-Albian tropical sequence from central Colombia using quantitative palynology (rarefied species richness and abundance) and used it to infer its predominant climatic conditions. Additionally, we compared our results with available quantitative data from three other sequences encompassing 70 floristic assemblages to determine latitudinal diversity patterns. KEY RESULTS Abundance of humidity indicators was higher than that of aridity indicators (61% vs. 10%). Additionally, we found an angiosperm latitudinal diversity gradient (LDG) for the Aptian, but not for the Albian, and an inverted LDG of the overall diversity for the Albian. Angiosperm species turnover during the Albian, however, was higher in humid tropics. CONCLUSIONS There were humid climates in northwestern South America during the Aptian-Albian interval contrary to the widespread aridity expected for the tropical belt. The Albian inverted overall LDG is produced by a faster increase in per-sample angiosperm and pteridophyte diversity in temperate latitudes. However, humid tropical sequences had higher rates of floristic turnover suggesting a higher degree of morphological variation than in temperate regions.

Modeling the complex impacts of timber harvests to find optimal management regimes for Amazon tidal floodplain forests

At the Amazon estuary, the oldest logging frontier in the Amazon, no studies have comprehensively explored the potential long-term population and yield consequences of multiple timber harvests over time. Matrix population modeling is one way to simulate long-term impacts of tree harvests, but this approach has often ignored common impacts of tree harvests including incidental damage, changes in post-harvest demography, shifts in the distribution of merchantable trees, and shifts in stand composition. We designed a matrix-based forest management model that incorporates these harvest-related impacts so resulting simulations reflect forest stand dynamics under repeated timber harvests as well as the realities of local smallholder timber management systems. Using a wide range of values for management criteria (e.g., length of cutting cycle, minimum cut diameter), we projected the long-term population dynamics and yields of hundreds of timber management regimes in the Amazon estuary, where small-scale, unmechanized logging is an important economic activity. These results were then compared to find optimal stand-level and species-specific sustainable timber management (STM) regimes using a set of timber yield and population growth indicators. Prospects for STM in Amazonian tidal floodplain forests are better than for many other tropical forests. However, generally high stock recovery rates between harvests are due to the comparatively high projected mean annualized yields from fast-growing species that effectively counterbalance the projected yield declines from other species. For Amazonian tidal floodplain forests, national management guidelines provide neither the highest yields nor the highest sustained population growth for species under management. Our research shows that management guidelines specific to a region’s ecological settings can be further refined to consider differences in species demographic responses to repeated harvests. In principle, such fine-tuned management guidelines could make management more attractive, thus bridging the currently prevalent gap between tropical timber management practice and regulation.

Identifying opportunities for long-lasting habitat conservation and restoration in Hawaii’s shifting climate

Conservation efforts in isolated archipelagos such as Hawaii often focus on habitat-based conservation and restoration efforts that benefit multiple species. Unfortunately, identifying locations where such efforts are safer from climatic shifts is still challenging. We aimed to provide a method to approximate these potential habitat shifts for similar data- and research-limited contexts. We modeled the relationship between climate and the potential distribution of native biomes across the Hawaiian archipelago to provide a first approximation of potential native biome shifts under end-of-century projected climate. Our correlative model circumvents the lack of data necessary for the parameterization of mechanistic vegetation models in isolated and data-poor islands. We identified locations consistently expected to remain the same in terms of the native biome compatibility by the end of the century with a robust evaluation of sources of uncertainty in our projections. Our results show that, despite large differences in climate projections considered, 35% of the areas considered are consistently projected to maintain their current compatibility to native biomes. By integrating our native biome compatibility projections with maps of current actual cover, we identified areas ideal for long-term habitat conservation and restoration. Our modeling approach can be used with relatively simple data; offers multiple forms of projection confidence estimates, model calibration, and variable selection routines; and is compatible with ensemble projections. This method is not only applicable to potential native cover, as done in this study, but to any set of vegetation classes that are related to environmental predictors available for modeling.

Beyond exposure, sensitivity and adaptive capacity: a response based ecological framework to assess species climate change vulnerability

As the impacts of global climate change on species are increasingly evident, there is a clear need to adapt conservation efforts worldwide. Species vulnerability assessments (VAs) are increasingly used to summarize all relevant information to determine a species’ potential vulnerability to climate change and are frequently the first step in informing climate adaptation efforts. VAs commonly integrate multiple sources of information by utilizing a framework that distinguishes factors relevant to species exposure, sensitivity, and adaptive capacity. However, this framework was originally developed for human systems, and its use to evaluate species vulnerability has serious practical and theoretical limitations. By instead defining vulnerability as the degree to which a species is unable to exhibit any of the responses necessary for persistence under climate change (i.e., toleration of projected changes, migration to new climate-compatible areas, enduring in microrefugia, and evolutionary adaptation), we can bring VAs into the realm of ecological science without applying borrowed abstract concepts that have consistently challenged species-centric research and management. This response-based framework to assess species vulnerability to climate change allows better integration of relevant ecological data and past research, yielding results with much clearer implications for conservation and research prioritization.

Floristic and climatic reconstructions of two Lower Cretaceous successions from Peru

ABSTRACT Climate during the Early Cretaceous in tropical South America has often been reconstructed as arid. However, some areas seem to have been humid. We reconstructed the floristic composition of two tropical stratigraphic successions in Peru using quantitative palynology (rarefied species richness and abundance), and used the abundance of aridity vs. humidity indicator species to infer the predominant climate conditions of this region. The Berriasian to Hauterivian La Merced succession was dominated by fern spores and was predominantly humid. The Albian Aguas Frias succession yielded rich palynofloras, with 127 species, and also indicates predominantly humid conditions. These results support the hypothesis that the west margin of South America was humid during the Early Cretaceous, thus improving the tropical climate reconstructions during the Cretaceous severe global warming episodes.

Multiple threats: Partitioning climate predictions from existing habitat and species stressors

T study was to determine if MaxEnt is useful for establishing the most suitable areas for the reintroduction of a wildlife species, the Iberian ibex (Capra pyrenaica). This method uses partial data (presence-only); thus, its reliability can be doubtful compared to models that use presence-absence data (general linearized model). This paper seeks to compare these models from their graphical representations (spatial correlation) instead of using the traditional comparisons of the statistics that they generate. We determined the potentiality of the territory via binomial logistic regression (GLM) and the graphical representation of the territory suitability with presence data only (MaxEnt). To compare both results, correlation analyses were performed. The most suitable areas for the species are similar although they were extended in GLM Model. In both cases, the variables of altitude, anthropogenic influence, and vegetation/stoniness are relevant for the presence of the species. The correlation analyses performed showed a strong relationship between both models. These results suggest that the use of the species’ presence-only distribution modelling employing MaxEnt is useful for defining the preferred locations of the species and can replace the absence-presence methods when information on the absence of the species is lacking.Climate Change is not a stationary phenomenon; it moves from time to time, it represents a major threat to mountainous biodiversity and to ecosystem integrity. The present study is an attempt to identify the current knowledge gap and the effects of climate change on mountainous biodiversity, a special reference to the Gilgit-Baltistan is briefly reviewed. Measuring the impact of climate change on mountain biodiversity is quite challenging, because climate change interacts with every phenomenon of ecosystem. The scale of this change is so large and very adverse so strongly connected to ecosystem services, and all communities who use natural resources. This study aims to provide the evidences on the basis of previous literature, in particular context to mountain biodiversity of Gilgit-Baltistan (GB). Mountains of Gilgit-Baltistan have most fragile ecosystem and are more vulnerable to climate change. These mountains host variety of wild fauna and flora, with many endangered species of the world. There are still many gaps in our knowledge of literature we studied because very little research has been conducted in Gilgit-Baltistan about climate change particular to biodiversity. Recommendations are made for increased research efforts in future this including jointly monitoring programs, climate change models and ecological research. Understanding the impact of climate change particular to biodiversity of GB is very important for sustainable management of these natural resources. The Government organizations, NGOs and the research agencies must fill the knowledge gap, so that it will help them for policy making, which will be based on scientific findings and research based.M Zoanthid taxonomy is typically based on polyp structure and coenenchyme characteristics. Their morphological identification is still understudied. Zoanthids were seen to increase in the past decade and covered almost entire intertidal zone, however their diversity was unknown and extensive work was then carried out. The coastal area of entire Gujarat state was studied. Rocky intertidal zone was surveyed monthly and Zoanthids were recorded. Morphological diversity was studied for the colour of oral disc and the polyp structure and colony morphology. Colour card technique was utilized for Zoanthids, which proves to be an effective tool for the assessment of zoanthid and their colour morphs. 25 colour morphs of Zoanthus sansibaricus, 5 of Z. aff. sociatus, 5 of Z. vietnamensis, 2 of Z. kuroshio, 4 of Palythoa mutuki, 2 of P. heliodidscus, 3 of P. tuberculosa. Site wise distribution showed that Zoanthids from Marine National Park exhibited more of Fluorescent colour morphs and rest showed more of different colour patterns. Rocky intertidal zone of Sutrapada showed maximum diversity and Okha showed least diversity. Colony patterns taken as attributes for the study of diversity resulted in understanding the utilization of the substratum. Flat and bulbous colonies of Palythoa tuberculosa and stoloniferous colonies of Zoanthus spp. and Palythoa mutuki and P. heliodiscus were recorded. It was concluded that substratum played a major role in understanding the colony pattern and showed that there was species wise change in colony pattern. The paper will describe about the morphology of both the polyp and colony.M Zoanthid taxonomy is typically based on polyp structure and coenenchyme characteristics. Their morphological identification is still understudied. Zoanthids were seen to increase in the past decade and covered almost entire intertidal zone, however their diversity was unknown and extensive work was then carried out. The coastal area of entire Gujarat state was studied. Rocky intertidal zone was surveyed monthly and Zoanthids were recorded. Morphological diversity was studied for the colour of oral disc and the polyp structure and colony morphology. Colour card technique was utilized for Zoanthids, which proves to be an effective tool for the assessment of zoanthid and their colour morphs. 25 colour morphs of Zoanthus sansibaricus, 5 of Z. aff. sociatus, 5 of Z. vietnamensis, 2 of Z. kuroshio, 4 of Palythoa mutuki, 2 of P. heliodidscus, 3 of P. tuberculosa. Site wise distribution showed that Zoanthids from Marine National Park exhibited more of Fluorescent colour morphs and rest showed more of different colour patterns. Rocky intertidal zone of Sutrapada showed maximum diversity and Okha showed least diversity. Colony patterns taken as attributes for the study of diversity resulted in understanding the utilization of the substratum. Flat and bulbous colonies of Palythoa tuberculosa and stoloniferous colonies of Zoanthus spp. and Palythoa mutuki and P. heliodiscus were recorded. It was concluded that substratum played a major role in understanding the colony pattern and showed that there was species wise change in colony pattern. The paper will describe about the morphology of both the polyp and colony.