Denny Fernandez del Viso

Mona Island protects one of the most important remnants of Caribbean dry forests and hosts a high diversity of rare and endangered plant and animal species. Feral ungulates (goats and pigs) were introduced to the island ~500 y ago, and their populations may be threatening the conservation of Mona Island’s native biodiversity. In this study, we used permanent fenced and unfenced plots at 4 different depression-forest sites on Mona Island to assess long-term (10-y) understory vegetation dynamics and the potential responses of this vegetation stratum to ungulate exclusion. Depression forests on Mona Island are of particular interest because they hold the highest diversity of tree species on the island and are critical nesting habitats for the endangered Cyclura cornuta stejnegeri (Mona Island Rock Iguana). Overall, our results showed that understory vegetation at depression forests on Mona Island is very diverse and highly dynamic. In terms of composition and abundance, the understory ...

ABSTRACT QuestionDoes the presence of the exotic grass Megathyrsus maximus influence the abundance and richness of plant communities on Mona Island Reserve?LocationSemi-arid shrubland, Mona Island Reserve in the Caribbean Region, Puerto Rico.Methods We used a large-scale experiment and established plots with different management treatments of Megathyrsus (complete and partial grass removal) to evaluate the effects of grass removal on plant community composition, coupled with measurements of microclimatic characteristics at this site. To complement this experiment, we selected areas not invaded by this grass with similar geomorphological features. We performed vegetation surveys of plant species richness and abundance in all plots and compared temporal changes in vegetation among treatments during a period of 31 mo (from May 2007 to December 2009). We also analysed the associations between changes in species richness and plant abundance with changes in environmental conditions at the plot level and at the island level (precipitation and temperature). ResultsPlant abundance increased following grass removal but changes in abundance were not necessarily linear over time. Species richness was significantly higher in grass removal plots but differences resulted from a consistent decrease in richness in plots with Megathyrsus. Both abundance and richness were highly variable over time regardless of treatment. The evaluation of temporal community dynamics suggested that these may be driven by temporal changes in climate, and in the case of manipulated plots, by changes in microclimatic conditions. Even when new species arrived into plots following grass removal these failed to establish. An evaluation of successional trajectories showed that removing the invasive grass does not lead to communities that are more similar to non-invaded sites, most likely due to changes in precipitation dynamics.Conclusions Grass removal does not necessarily result in predictable successional changes in plant communities where natural regeneration is allowed to occur. Restoring grass-invaded areas in this semi-arid reserve to conditions that simulate current non-invaded sites would likely require restoration strategies that combine grass management with activities that facilitate the establishment of native species. This may be a general occurrence in grass-invaded areas in semi-arid regions.

Goals and Intended Outcome: The goals are to: 1) create and validate a set of instructional materials designed to develop and assess process skills important in conservation biology and other integrative fields, and 2) pilot developed teaching and assessment materials in diverse classroom settings. We expect to increase our understanding of how to promote data analysis, critical thinking, and oral communication skills in students. Methods and Strategies: After creation and validation of instructional materials designed to develop and assess critical thinking, data analysis, and oral communication, we are piloting the materials in a diverse group of academic institutions across the US. Each faculty participant implements a set of instructional materials for a particular skill during two separate semesters of the same course. Evaluation Methods and Results: Our evaluation plan includes formative and summative evaluation activities and the application of diverse tools, both quantitative and qualitative. Project personnel are undertaking ongoing project evaluation with input from project advisers. An evaluation specialist will evaluate the project at mid-point and at its conclusion. Dissemination: We are working with 18 faculty members from diverse academic institutions across the US, including Puerto Rico and the Virgin Islands. In the future, we will make instructional units available to a broader audience of faculty members and conservation trainers through the NCEP website (ncep.amnh.org) Impact: Through this project, faculty members participated collaboratively in the development of teaching and assessment materials. By implementing these materials in their courses, faculty participants are not only learning about their students’ development of process skills, they are also learning about their own teaching practices. In terms of students, this project intends to increase students’ proficiency with process skills important in conservation biology. They will do this through a series of exercises and classroom discussion as well as through self-reflection about the targeted skill. Challenges: Participating faculty found our original experimental design of teaching and assessing more than one skill at a time to be logistically challenging. We adjusted the design to implement teaching and assessment materials for only one skill at a time. This modification did not change the overall goal of the project. Also, faculty members’ participation on the development and validation of the teaching materials was less that expected. Project personnel spent more time than planned working on these tasks. Expected Outcomes: In this comparative, multi-year study we will gather new evidence on teaching and assessment approaches that can help develop process skills in undergraduate students. We expect that classroom implementation of the developed teaching and assessment materials will lead to positive gains in students’ proficiency in critical thinking, data analysis and oral communication skills as well as increased discipline-specific content knowledge. We expect the magnitude of student skill gains will be greater in intensive vs. light teaching intervention treatments. Overall, we expect to increase our understanding of how to promote data analysis, critical thinking, and oral communication skills in undergraduate students. Data Impact: The instructional unit for each skill consists of pre/post student self-assessments, two exercises with rubrics for evaluation of student performance, and pre/post exercise content assessments. We use these tools to measure gains in students’ self-confidence on the skill, in the process skill, and in their knowledge of specific content. We use these tools in two classroom settings: one with an intensive classroom discussion and another with an individual student reflection on the skill. Comparisons between these settings will allow us to determine the effects of teaching intervention on students’ gains in the skill. We will also assess gains in faculty through pre/post questionnaires. Collection Methods: We are working with 18 faculty members who are implementing one of the instructional units in their courses. Six professors are using the instructional unit that targets critical thinking skills, seven the one for data analysis skills, and five for oral communication skills. Each faculty member will implement these units in two separate semesters, one with an intensive classroom discussion and another with an individual student reflection. Key Findings: To date we have results from students using instructional units on data analysis with an intensive classroom discussion (DA; N=104), oral communication with individual student reflection (OC; N=84) and critical thinking with both individual student reflection (CT; N=78) and intensive classroom discussion (N=42). For all three skills we find that students improve in skill performance. However, the degree of improvement varied among skills…

Background/Question/Methods Understanding and conserving the biosphere increasingly requires proficiency in skills including critical thinking, data analysis, oral communication, broad synthesis of information and teamwork across diverse groups. However, a real concern exists that US undergraduate science students do not currently develop these important process skills needed as professionals. First, our work asks “how can we best ‘operationalize’ teaching of process skills?” Second, we must also discover how to evaluate development of specific process skills in our students. Such assessment allows us to determine if we have succeeded in teaching these skills with a gain or loss in content understanding. Here, we present the design and preliminary results of a recently launched experimental study aimed at these two tasks. The study brings together faculty from diverse institutions and professional conservation biologists to create and validate a set of instructional materials for pr...

Background/Question/Methods The fast pace of biological data generated nowadays calls for our biology students to be proficient in quantitative skills such as data analysis. This study examined how well undergraduate students can develop data analysis skills relevant to ecology and conservation biology over the course of a single semester. Students completed two data analysis exercises, pre and post self-assessments of confidence in data analysis skills, a classroom discussion, and pre/post content assessments. The two data analysis exercises were adapted from the free online teaching modules on the Network of Conservation Educators and Practitioners website (www.ncep.amnh.org). Between the first exercise (a demography problem involving palm harvests and parrots) and second exercise (calculating diversity indices for spider communities), a data analysis teaching intervention was administered in all classes. Instructional and assessment materials were created and validated by 24 cons...

The effective preservation and sustainable use of ecosystems is a complex endeavor that requires proficiency in skills of critical thinking, data analysis, oral communication, broad synthesis of information and teamwork across diverse groups. However, there is concern that US undergraduate science students do not currently develop these fundamental process skills they will need as professionals. In this study, we investigate how we can best 'operationalize'the teaching of process skills and how we can assess their development in ...

Page 1. BIOTROPICA 23(4a): 393-399 1991 Changes in Light Availability Following Hurricane Hugo in a Subtropical Montane Forest in Puerto Rico1 Denny S. Fernandez and Ned Fetcher Department of Biology, University of Puerto Rico, Rio Piedras, Puerto Rico 00931, USA ...

The demographic dynamics of plant populations will depend on the relative role of density-dependent versus density-independent factors on population reg- ulation. Density-independent factors (i.e. changes in climate, fire, hurricanes) will affect plant survival and reproduction within a population in a manner that is independent of the density of individuals. 

Page 1. PHYSIOLOGIA PLANTARUM 94: 560-565. 1995 Primed in Denmark - all rights reserved Chronic photoinhibition in seedlings of tropical trees Yolanda Castro, Ned Fetcher and Denny S. Fernandez Castro, Y., Fetcher N. and Fernandez, DS 1995. ...

ABSTRACT Hurricanes are a major factor influencing forest structure and have been linked to higher incidences of multiple‐stemmed trees in Caribbean dry forests relative to the continent. In Sept 1998, category 3 Hurricane Georges passed over Mona Island. This island, unlike others in the Caribbean, has had feral goats for five centuries. In this study we addressed the following questions: (i) what are the short‐term (4 mo) and long‐term (10 yr) responses of Mona Island's dry forests to hurricane disturbance in terms of forest structure and tree mortality; and (ii) is there any effect of goat exclusion on the recovery process and forest structure after the hurricane? In this study we used long‐term monitoring of fenced and unfenced plots to evaluate the interplay between goat herbivory and hurricane effects on tree‐community structural dynamics. We found that differences in structure between Mona Island's dry forest and other tropical dry forests are related to changes in species composition that may have been triggered by introduced goats.

ABSTRACT QuestionDoes the presence of the exotic grass Megathyrsus maximus influence the abundance and richness of plant communities on Mona Island Reserve?LocationSemi-arid shrubland, Mona Island Reserve in the Caribbean Region, Puerto Rico.Methods We used a large-scale experiment and established plots with different management treatments of Megathyrsus (complete and partial grass removal) to evaluate the effects of grass removal on plant community composition, coupled with measurements of microclimatic characteristics at this site. To complement this experiment, we selected areas not invaded by this grass with similar geomorphological features. We performed vegetation surveys of plant species richness and abundance in all plots and compared temporal changes in vegetation among treatments during a period of 31 mo (from May 2007 to December 2009). We also analysed the associations between changes in species richness and plant abundance with changes in environmental conditions at the plot level and at the island level (precipitation and temperature). ResultsPlant abundance increased following grass removal but changes in abundance were not necessarily linear over time. Species richness was significantly higher in grass removal plots but differences resulted from a consistent decrease in richness in plots with Megathyrsus. Both abundance and richness were highly variable over time regardless of treatment. The evaluation of temporal community dynamics suggested that these may be driven by temporal changes in climate, and in the case of manipulated plots, by changes in microclimatic conditions. Even when new species arrived into plots following grass removal these failed to establish. An evaluation of successional trajectories showed that removing the invasive grass does not lead to communities that are more similar to non-invaded sites, most likely due to changes in precipitation dynamics.Conclusions Grass removal does not necessarily result in predictable successional changes in plant communities where natural regeneration is allowed to occur. Restoring grass-invaded areas in this semi-arid reserve to conditions that simulate current non-invaded sites would likely require restoration strategies that combine grass management with activities that facilitate the establishment of native species. This may be a general occurrence in grass-invaded areas in semi-arid regions.

Page 1. BIOTROPICA 23(4a): 393-399 1991 Changes in Light Availability Following Hurricane Hugo in a Subtropical Montane Forest in Puerto Rico1 Denny S. Fernandez and Ned Fetcher Department of Biology, University of Puerto Rico, Rio Piedras, Puerto Rico 00931, USA ...