Decomposition

© 2012 Pearson Education, Inc. Respiration Grazer system Decomposer system Net primary productivity Dead organic matter (a) Forest (b) Grassland From terrestrial catchment (d) Stream community (c) Phytoplankton community Respiration Grazer system Decomposer system Net primary productivity Dead organic matter Respiration Grazer system Decomposer system Net primary productivity Dead organic matter Respiration Grazer system Decomposer system Net primary productivity Dead organic matter Figure 21.22

We used litter baskets to measure the timing of L. maackii litter input. -Timing is the same as natives, except for a late- season pulse

- Invasive species litter, native species litter, in bags. - The bags were under or away from honeysuckle shrubs - Measured: (1) mass loss (2) nitrogen loss (3) microbial community dynamics

-Decomposition rates for L. maackii much faster than for native species. -This implies accelerated nutrient cycling.

Nitrogen loss very rapid

Phospholipid Fatty Acid (PLFA-microbial) assay (membrane biochemical markers, gives a view into community composition) Analyzed using Principle Components Analysis (PCA) Microbial community analysis Honeysuckle samples at 1 month differentiate from native species Microbial community dynamics

-Throughout the decomposition sequence, L. maackii remains distinct. -Microbial succession? Microbial community dynamics

Energy, nutrients, habitat substrate Terrestrial inputs (autumn)

Energy, nutrients, habitat substrate Basal resource for aquatic organisms Bottom-up regulation of aquatic foodwebs Terrestrial inputs (autumn)

Energy, nutrients, habitat substrate Basal resource for aquatic organisms Bottom-up regulation of aquatic foodwebs Predator Shredder Filtering-Collector Scraper Gathering-Collector Terrestrial inputs (autumn)

Field Observations:

…to determine the impacts of terrestrial invasive shrub, L. maackii, on aquatic ecosystems Cross system subsidies and in-stream organic matter processing Aquatic macroinvertebrate community

Methods: Leaf Breakdown Predator ShredderFiltering- collector ScraperGathering- collector ash free dry mass (AFDM) 1) Invasive: L. maackii 2) Native: Fraxinus & Platanus 3) Mix: Lonicera, Fraxinus & Platanus Treatments

Honeysuckle leaf breakdown was 4-5x faster compared to native leaf packs (P < 0.01) Fig. 1 Linear regression models of ln leaf material remaining (as AFDM) over ADD to determine decay coefficients (k) for native, invasive and mix leaf packs in three 3 rd order steams of southwestern Ohio, USA. Letter comparisons are between treatments and were from one-way ANOVA analyses based on mean, sample size, and standard error from linear regression models Fig. 4: Leaf litter remaining for leaf packs composed of L. maackii, native, and a L. maackii-native mix in three headwater streams of southwestern Ohio. Significant differences of Bonferroni post-tests (P < 0.05) after two- way ANOVA are represented with different letters between treatments within each sampling day.

Gathering-Collectors significantly dominated the FFG within L. maackii leaf packs (P < 0.01) There were differences in the abundance pattern of FFG between leaf pack treatments Aquatic macroinvertebrate functional feeding group colonization of L. maackii, mix and native leaf packs in 3 headwater streams. Taken from McNeish et al (2012).

Methods: Riparian Restoration Invasive Native

Methods: Riparian Restoration Removal Control Macroinvertebrate community 160 m Flow

Total Macroinvertebrate Density

The mass remaining after a decomposition process for leaf materials often is a function of lignin concentration.

Red maple litter decomposes at different rates, at different location….why?

I am an ecologist…..