Understanding the influences of invasion on native
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Azul Calderon, Chenxi Lu, Kaira Hernandez, Thiyara Weerardena, Ysidro Vasquez
Invasive species pose a significant threat to many natural ecosystems worldwide and have negative impacts on the native biodiversity and functions of an ecosystem. These invasions are expected to increase due to climate change. Previous research has found that as native biodiversity in a system increases, the vulnerability to invasion decreases. However, other research has found that if the environment is suitable, both native and invasive species have the ability to increase in abundance, regardless of native biodiversity. The objective of this project was to understand how an ecosystem’s biodiversity affects the likelihood of invasive species taking over habitat and which mechanisms allow invasive species to take over habitat. We hypothesized that 1) native species abundance (percent coverage) is positively correlated with invasive species abundance, 2) native species richness (number of species) is negatively correlated with invasive species richness, 3) an ecosystem’s biodiversity does not affect invasive species chance in taking over habitat, and 4) higher precipitation will have a correlation with invasive species . We compared plant diversity data collected by NEON scientists in three sites in the Sierra National Forest that describes the estimated number of plant species found in different plots and throughfall precipitation at all three sites. Our results indicate that invasive species abundance is negatively correlated with native abundance, but invasive richness is positively correlated with native richness. However, precipitation had a negative correlation with both native and invasive species richness. Thus, the biodiversity of these ecosystems seems to not affect the likelihood of invasive species taking over, highlighting the complexity of ecological interactions. Understanding these dynamics is crucial for effective conservation and management strategies, as it provides valuable insights into how biodiversity influences the prevalence of invasive species in natural habitats. |
Space use in small mammals. |
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Elliot Adlof, Yvette Ayala, Gurleen Dhanoa, Jesus Fuentes, Alison Oliver
Small mammals are important prey species, can act as early indicators of impacts of habitat fragmentation and disturbance, and can carry pathogens that impact human health. Understanding the spatial ecology of small mammals can offer valuable insight into wildlife conservation efforts, habitat management, and species population dynamics. Here, we study the relationship between home range size, sex, and population density in deer mice (Peromyscus maniculatus). We used data from repeat mammal trap data across the 47 National Ecological Observatory Network (NEON) terrestrial field sites from 2013 to 2024. We found that home range size is inversely correlated with population density. We also found that males have larger home range sizes than females. This result aligns with previous studies suggesting that males often need larger territories for mating opportunities and resource acquisition. Future research can investigate if the relationship between home range size and sex is impacted by disturbances, such as fire and earthquakes, and if there is seasonal variation in home range size by sex. |
Ground beetle communities in evergreen and deciduous forests. |
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Ashley Moore, Richard Nava, Junhee Oh, Jules Thant
Forests are vital for regulating global temperature, serve as carbon sinks, and support economies, but threats such as climate change and mismanagement are shifting forest compositions. Forest composition, such as forest tree type, affects forest floors which are greatly shaped by leaf litter and plant debris, as they provide both nutrients and shelter for many organisms. Ground beetles rely on this important resource as prominent members of the forest floor. Ground beetles play a critical role in forest ecosystems, serving in nutrient cycling, decomposition, and overall ecosystem health, making their study essential for understanding biodiversity changes in forests under environmental stress. This research investigates how forest composition, specifically the dominance of evergreen and deciduous trees, influences ground beetle (Carabidae) communities. We predicted that deciduous forests, with their higher structural diversity and nutrient-rich leaf litter, would support greater ground beetle diversity, species richness and density compared to evergreen forests. We analyzed publicly available data from all 47 National Ecological Observatory Network (NEON) terrestrial sites, focusing on deciduous and evergreen forest plots. Ground beetle data was collected using pitfall traps, and metrics such as Shannon diversity, species richness, and beetle density were calculated. Nonparametric Wilcoxon tests were used to compare forest types, accounting for the non-normal distribution of data. Deciduous forests had significantly higher ground beetle diversity, species richness, and beetle density than evergreen forests. These results support the hypothesis that deciduous forests create better habitats for ground beetles underscoring the ecological significance of leaf litter quality and habitat heterogeneity in possibly shaping these communities. While the results align with expectations, the continental scale of the analysis highlights the importance of regional and site-specific variations. Future studies should directly investigate how microhabitat variables such as leaf litter nutrient composition, soil temperature, and moisture influence ground beetle communities. Additionally, exploring how beetle feeding niches (e.g., carnivores vs. detritivores) vary across forest types could uncover broader ecological impacts. Understanding how tree composition impacts ground beetle communities can inform forest management strategies aimed at conserving biodiversity and maintaining ecosystem functions in the face of climate change and habitat alterations. |