Many ecologists and conservation biologists use species distribution models to predict where species should live based on factors like temperature, precipitation, and habitat. This technique is really important for species or habitats that are hard to sample. If we want to conserve or protect these species, we need to have better information about where they live, thus we use models. However, using a survey of the literature from 2003-2015 we found that these studies are mostly being done in: 1) terrestrial systems (over 85%; few in marine or freshwater ecosystems), 2) North America or Europe (few studies in Africa, Asia), and 3) on plants, birds, or mammals (few on fish, amphibians, reptiles). We also found that scientists have been slow to incorporate factors into models that could greatly affect species distributions, such as dispersal and interactions with other species (e.g., competition, predation). Importantly, very few studies reported the results of the models with and without these biological factors, making it difficult to know how important these factors might be now and in the future. Additionally, nearly half of studies did not use the model to predict where species might live in the future given climate change predictions, which we consider a missed opportunity. Lastly, with a limited set of studies, we found that the overall size of the study area (i.e., extent) and the cell size used in the model (i.e., grain) did not have an effect on the importance of dispersal and species interactions. However, with a small sample size, we interpret this outcome cautiously and encourage scientists planning to use these models to carefully consider decisions about study extent and grain size.
Take home message: Conservation decisions could be driven by incomplete information – we need models of underrepresented ecosystems, taxa, and regions; models that consider the effects of climate change; and models that are more biologically realistic and robust.
Check out the paper published in PLoS One here.
Research was funded by the National Science Foundation. The Ecological Society of America sponsored an early career workshop in 2013 that initiated this international collaboration of scientists from USA, Taiwan, and Israel.
Every year the Harvard Forest Long Term Ecological Research Site hosts an annual symposium of all scientists who work at the forest that has been studied for over 100 years in Petersham, Massachusetts. This year Dr. Sydne Record presented her insights on the value of long term ecological experiments and postdoc Dr. John Grady presented a poster on his work on energy partitioning in forests.
The highlight of the day for Sydne was meeting up with Tess McCabe (BMC ’15, former Harvard Forest REU) who is working on her PhD in the Dietze Lab at Boston University.
When forests change, do the ants that live there change, too?
This is the question that Dr. Sydne Record (Bryn Mawr Biology), Tempest McCabe (BMC ‘16), and others asked in their latest paper “Identifying foundation species in North American forests using long-term data on ant assemblage structure”. This paper formed the foundation of Tess McCabe’s senior thesis in Biology and was the focus of her summer Research Experiences for Undergraduates internship at Harvard Forest funded by the National Science Foundation and Bryn Mawr’s LILAC Program. Tess is now a pursuing her PhD at Boston University.
Ants provide a lot of different services to forests; ants aerate soils, decompose wood, and disperse seeds. However, these services depend on the different community diversity of ants. Dr. Record and colleagues wondered if the death of trees within a forest would change the number of species in that forest or the number of services the ant community provided.
To test this, Record and colleagues collected ants at two sites: one with oaks removed at the Black Rock Forest Future of Oak Forests Experiment and one with hemlocks removed at the Harvard Forest Hemlock Removal Experiment. Then for twelve years, they looked at how ant community diversity changed compared to the same oak and eastern hemlock forests without the tree-removals.
They found that the way the ant community changed depended on the type of forest. When eastern hemlocks were lost, the ant community changed taxonomically and in some of the services the ant community could provide. When oaks were lost, the ant community did not change in terms of species composition or the services that they provide to the forest ecosystem. These results support the hypothesis that eastern hemlock is a foundation species.
Dr. Record’s work implies that different trees have different levels of influence over their surrounding ecosystem. The paper suggests that eastern hemlock defines its ecosystem, and that removing eastern hemlocks has effects that cascade down to the ant-level. Removing an oak has fewer effects. Understanding how the loss of particular tree species will affect an ecosystem is essential for conservation efforts.
Last week Dr. Sydne Record and postdoc John Grady returned from a great week in Santa Barbara, CA at the National Center for Ecological Analysis and Synthesis. This was the second meeting of the NASA BIOxGEO working group led by Sydne. The goal of the working group is to better understand how remotely sensed geodiversity data products can be used to predict biodiversity hot and cold spots across spatial scales.
Read, Q.D., B. Baiser, J. Grady, P.L. Zarnetske, S. Record, J. Belmaker, and L. Beaudrot. 2018. Tropical bird species have narrower body-size niches. Biology Letters 14 (1), 20170453.
Why do species in the tropics appear to be more sensitive to small changes in their environment? This is a question that has puzzled ecologists for generations. Two famous papers from fifty years ago explored this topic. One suggested that species closer to the equator tend to have more specialized diet requirements, and the other observed that environments near the equator have very stable climates, so that species that live there cannot tolerate big swings in temperature. Those ideas led us to predict that bird species outside the tropics would vary more in their body size than birds in the tropics. We tackled that question by compiling bird specimen data from museums worldwide and comparing pairs of sister species. In each pair, one of which lives in the tropics and the other closer to the poles, we compared how much the body size varied. We found that tropical birds indeed have less variable body sizes, supporting our prediction and suggesting that tropical birds will be more susceptible to ongoing human-caused environmental changes.
This research is supported by a grant from the National Science Foundation. Quentin Read and John Grady are postdoctoral fellows co-mentored by Dr. Record (Bryn Mawr) and Dr. Zarnetske (Michigan State University).
Applications are now open for the 2018 Harvard Forest Summer Research Program, an opportunity for college and university students across the U.S. to participate in 11 weeks (May 21-August 3, 2018) of paid, independent research. Dr. Record has two projects that students can join this summer:
This has been a busy couple months of communicating science for the Record Lab! In September, Kalaina Thorne (BMC ’18) presented her summer research from Harvard Forest at the Young Researcher’s Conference at the University of Maryland College Park. Kalaina received special funding from the Alliance for Diversity in Science and Engineering to attend the conference. Postdoctoral fellow John Grady presented an invited seminar at Michigan State University’s Hanover Seminar Series in the Department of Forestry in October. Dr. Record presented on a panel on data science at all women colleges at the American Statistical Association’s Women in Data Sciences conference in La Jolla, California in October.
Dr. Sydne Record and postdoc Dr. John Grady presented their work on NSF and NASA funded projects at the Ecological Society of America’s Annual Meeting in Portland, OR last week. A highlight of the meeting for Sydne was catching up over lunch with Tess McCabe (BMC ’16) at a local farmer’s market. Tess is currently a graduate student at Boston University.
Kalaina Thorne (BMC ’18) joined Dr. Sydne Record and postdoc Dr. John Grady at Harvard Forest this summer to do field research as part of the Harvad Forest Summer Research Experiences for Undergraduates Program. Check out Kalaina’s blog post here: http://harvardforest.fas.harvard.edu/blog/what%E2%80%99s-out-there-small-yet-large-study-harvard-forest . Kalaina was a total rock star and tagged over 1300 seedlings as part of a new project within the Harvard Forest ForestGeo plot that is within the National Ecological Observatory Network (NEON) footprint at Harvard Forest and is also part of a greater global Smithsonian network of forest plots (http://www.forestgeo.si.edu/).
As the semester wraps up, we’re excited to head out into the field! Kya Hoerr is headed to Penn State for an REU on agroecology. Kalaina is headed to an REU at Harvard Forest with Sydne and John.