Implications For Ecological Interactions Research Articles

Volatile Organic Compound Emissions in the Changing Arctic

Arctic ecosystems have long been thought to be minimal sources of volatile organic compounds (VOCs) to the atmosphere because of their low plant biomass and cold temperatures. However, these ecosystems experience rapid climatic warming that alters vegetation composition. Tundra vegetation VOC emissions have stronger temperature dependency than current emission models estimate. Thus, warming, both directly and indirectly (via vegetation changes) likely increases the release and alters the blend of emitted plant volatiles, such as isoprene, monoterpenes, and sesquiterpenes, from Arctic ecosystems. Climate change also increases the pressure of both background herbivory and insect outbreaks. The resulting leaf damage induces the production of volatile defense compounds, and warming amplifies this response. Soils function as both sources and sinks of VOCs, and thawing permafrost is a hotspot for soil VOC emissions, contributing to ecosystem emissions if the VOCs bypass microbial uptake. Overall, Arctic VOC emissions are likely to increase in the future, with implications for ecological interactions and atmospheric composition.

The Variation of Chemical Constituents across Altitudes in the Himalayan Kumaon Region: Exploring Nature's Wonders

This article investigates the variation in chemical constituents at different altitudes in the Himalayan region, specifically focusing on the Kumaon region. The study aims to understand the impact of altitude on the chemical composition of plants and its implications for ecological interactions and human health. Extensive field surveys were conducted across various altitudes, and plant samples were collected for chemical analysis. The results revealed significant variations in the chemical constituents of plants at different altitudes, including secondary metabolites such as alkaloids, flavonoids, and phenolic compounds. The study also identified specific altitude-dependent patterns, with certain compounds being more abundant or absent at particular altitudes. These variations in chemical constituents can be attributed to environmental factors such as temperature, humidity, and solar radiation, which change with altitude. The findings highlight the importance of considering altitude as a key factor in studying the chemical ecology of the Himalayan region. Understanding these variations can have significant implications for conservation efforts, pharmaceutical research, and traditional medicine practices in the region. Further research is needed to explore the ecological and physiological mechanisms underlying these altitude-related variations in chemical constituents.

Mines over matter: Effects of foliar particulate matter on the herbivorous insect, Helicoverpa armigera

AbstractCoalmines, which are major contributors of particulate matter in the form of coal dust, are expanding globally into rural environments. However, ecological effects on organisms interacting with coal‐dusted foliage in mining landscapes are unknown. We tested how the behaviour, development and survival of a polyphageous insect herbivore, Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) is affected by consuming tomato leaves Lycopersicon esculentum laden with coal dust. We tested (a) feeding site establishment preference of neonates, (b) feeding behaviour and leaf consumption of late‐instar larvae, (c) survival of neonates and (d) survival and development of late‐instar larvae. We found that coal dust consumption increased the mortality of late‐instar larvae but did not influence their development. Despite long‐term implications for survival, late‐instar larvae did not adjust their feeding behaviour or the amount of leaf material consumed in response to foliar coal dust. Contrastingly, when neonate H. armigera were given a choice, they avoided establishing themselves on the coal‐dusted adaxial surface of leaves. Neonate mortality was 99% within 7 days, with no effect of coal dust. Our study provides the first data on the impact of coal dust on an insect herbivore. This has implications for ecological interactions in landscapes adjoining coalmines.

Evolved pesticide tolerance influences susceptibility to parasites in amphibians.

Because ecosystems throughout the globe are contaminated with pesticides, there is a need to understand how natural populations cope with pesticides and the implications for ecological interactions. From an evolutionary perspective, there is evidence that pesticide tolerance can be achieved via two mechanisms: selection for constitutive tolerance over multiple generations or by inducing tolerance within a single generation via phenotypic plasticity. While both mechanisms can allow organisms to persist in contaminated environments, they might result in different performance trade‐offs including population susceptibility to parasites. We have identified 15 wood frog populations that exist along a gradient from close to agriculture and high, constitutive pesticide tolerance to far from agriculture and inducible pesticide tolerance. Using these populations, we investigated the relationship between evolutionary responses to the common insecticide carbaryl and host susceptibility to the trematode Echinoparyphium lineage 3 and ranavirus using laboratory exposure assays. For Echinoparyphium, we discovered that wood frog populations living closer to agriculture with high, constitutive tolerance experienced lower loads than populations living far from agriculture with inducible pesticide tolerance. For ranavirus, we found no relationship between the mechanism of evolved pesticide tolerance and survival, but populations living closer to agriculture with high, constitutive tolerance experienced higher viral loads than populations far from agriculture with inducible tolerance. Land use and mechanisms of evolved pesticide tolerance were associated with susceptibility to parasites, but the direction of the relationship is dependent on the type of parasite, underscoring the complexity between land use and disease outcomes. Collectively, our results demonstrate that evolved pesticide tolerance can indirectly influence host–parasite interactions and underscores the importance of including evolutionary processes in ecotoxicological studies.

Long-term responses of sandy beach crustaceans to the effects of coastal armouring after the 2010 Maule earthquake in South Central Chile

Earthquakes and tsunamis are large physical disturbances frequently striking the coast of Chile with dramatic effects on intertidal habitats. Armouring structures built as societal responses to beach erosion and shoreline retreat are also responsible of coastal squeeze and habitat loss. The ecological implications of interactions between coastal armouring and earthquakes have recently started to be studied for beach ecosystems. How long interactive impacts persist is still unclear because monitoring after disturbance generally extends for a few months. During five years after the Maule earthquake (South Central Chile, February 27th 2010) we monitored the variability in population abundances of the most common crustacean inhabitants of different beach zones (i.e. upper, medium, and lower intertidal) at two armoured (one concrete seawall and one rocky revetment) and one unarmoured sites along the sandy beach of Llico. Beach morphology changed after the earthquake-mediated uplift, restoring upper- and mid-shore armoured levels that were rapidly colonized by typical crustacean species. However, post-earthquake increasing human activities affected the colonization process of sandy beach crustaceans in front of the seawall. Lower-shore crab Emerita analoga was the less affected by armouring structures, and it was the only crustacean species present at the three sites before and after the earthquake. This study shows that field sampling carried out promptly after major disturbances, and monitoring of the affected sites long after the disturbance is gone are effective approaches to increase the knowledge on the interactive effects of large-scale natural phenomena and artificial defences on beach ecology.

Doubled volatile organic compound emissions from subarctic tundra under simulated climate warming

*Biogenic volatile organic compound (BVOC) emissions from arctic ecosystems are important in view of their role in global atmospheric chemistry and unknown feedbacks to global warming. These cold ecosystems are hotspots of climate warming, which will be more severe here than averaged over the globe. We assess the effects of climatic warming on non-methane BVOC emissions from a subarctic heath. *We performed ecosystem-based chamber measurements and gas chromatography-mass spectrometry (GC-MS) analyses of the BVOCs collected on adsorbent over two growing seasons at a wet subarctic tundra heath hosting a long-term warming and mountain birch (Betula pubescens ssp. czerepanovii) litter addition experiment. *The relatively low emissions of monoterpenes and sesquiterpenes were doubled in response to an air temperature increment of only 1.9-2.5 degrees C, while litter addition had a minor influence. BVOC emissions were seasonal, and warming combined with litter addition triggered emissions of specific compounds. *The unexpectedly high rate of release of BVOCs measured in this conservative warming scenario is far above the estimates produced by the current models, which underlines the importance of a focus on BVOC emissions during climate change. The observed changes have implications for ecological interactions and feedback effects on climate change via impacts on aerosol formation and indirect greenhouse effects.

Do genetically modified plants impact arbuscular mycorrhizal fungi?

The development and use of genetically modified plants (GMPs), as well as their ecological risks have been a topic of considerable public debate since they were first released in 1996. To date, no consistent conclusions have been drawn dealing with ecological risks on soil microorganisms of GMPs for the present incompatible empirical data. Arbuscular mycorrhizal fungi (AMF), important in regulating aboveground and underground processes in ecosystems, are the most crucial soil microbial community worthy of being monitored in ecological risks assessment of GMPs for their sensitivity to environmental alterations (plant, soil, climatic factor etc.). Based on current data, we suggest that there is a temporal-spatial relevance between expression and rhizosphere secretion of anti-disease and insecticidal proteins (e.g., Bt-Bacillus thuringiensis toxins) in and outer roots, and AMF intraradical and extraradical growth and development. Therefore, taking Bt transgenic plants (BTPs) for example, Bt insecticidal proteins constitutive expression and rhizosphere release during cultivation of BTPs may damage some critical steps of the AMF symbiotic development. More important, these processes of BTPs coincide with the entire life cycle of AMF annually, which may impact the diversity of AMF after long-term cultivation period. It is proposed that interactions between GMPs and AMF should be preferentially studied as an indicator for ecological impacts of GMPs on soil microbial communities. In this review, advances in impacts of GMPs on AMF and the effect mechanisms were summarized, highlighting the possible ecological implications of interactions between GMPs and AMF in soil ecosystems.

Chemosensory signals in stream habitats: implications for ecological interactions

AbstractThe combination of varying aquatic habitats and flow regimes creates a complex stimulus environment from which sensory information can be extracted. Previous studies with crayfish in artificial stream settings have shown that altering the temporal and spatial structure of an odor plume modifies orientation behavior. Exposure to more temporally complex odor signals enables crayfish to locate food more efficiently. To link these studies to a more natural setting, we examined how odor signals are dispersed in 3 physically different habitats within the Maple River in Pellston, Michigan, USA, by simultaneously measuring flow patterns and odor plume characteristics. These microhabitats consisted of sections of the stream with gravel, transition (gravel and sand), or sand substrate. Flow measurements were taken using an Acoustic Doppler Velocimeter while simultaneous in situ odor plume measurements were made with an Epsilon electrochemical system. Flow had more turbulent energy in gravel and transition h...

Anthropogenic and climate forcing on the long-term changes of planktonic rotifers in Lake Geneva, Europe

Climatic and anthropogenic forcing on the long-term changes in the community of rotifers were investigated during the period 1969–98 in Lake Geneva. The results showed a cascade of links between large-scale climate indices and phosphorus concentrations, acting as main factors, and the long-term changes in the pelagic ecosystem in Lake Geneva. Accordingly, we identified substantial changes in the structure of the rotifer community related to changes of the food web at the study site during the last three decades. Furthermore, we identified an abrupt shift in ∼1987 in the size structure of the rotifer community, which was closely linked with both increase in water temperature and decrease in phosphorus. The observed ecological changes in phytoplankton variability and rotifer size structure are discussed in the framework of modification in the trophic state of Lake Geneva. Overall, these results deserve attention by showing that strong environmental changes in pelagic ecosystems affect not only the abundance of pelagic populations but also their size structure, which has implications for ecological interactions and coupling between low and high trophic levels. The size-based approach we have developed appears complementary to the taxonomic one (i.e. keystone species), and therefore it is a useful tool to assess long-term changes in the functioning of the plankton communities.

Diel movement patterns of the Hawaiian stingray, Dasyatis lata: implications for ecological interactions between sympatric elasmobranch species

The Hawaiian stingray, Dasyatis lata, is a common benthic elasmobranch in nearshore Hawaiian waters. Acoustic telemetry was used to track the movements of seven rays in Kaneohe Bay, Oahu, Hawaii. Rays were tracked continuously over 31–74 h periods. Geographical movements were analyzed to determine space utilization and rate of movement. Rays were found to utilize significantly larger activity spaces at night (0.83±0.70 km2) (mean±SD) than during the day (0.12±0.15 km2). Mean total activity space for rays tracked was 1.32±0.75 km2. Rates of movement were also significantly higher at night (0.34±0.30 km h-1) than during the day (0.15±0.22 km h-1). Average straight-line swimming speed was 0.64±0.16 km h-1, with a maximum observed swimming speed of 1.9 km h-1. Tidal stage had no effect on rate of movement. Comparison with previously published data on juvenile scalloped hammerhead sharks, Sphyrna lewini, in Kaneohe Bay revealed a high degree of overlap in habitat use and time of activity, suggesting possible ecological interactions between these two species.