Community Dynamics of Seed Rain in Mixed Evergreen Broad-leaved and Deciduous Forests in a Subtropical Mountain of Central China

Abstract Seed dispersal has key implications for community dynamics and restoration ecology. However, estimating seed rain (the number and diversity of seeds arriving in a given area) is challenging, and the lack of standardization in measurement prevents cross-site comparisons. Seed trap effectiveness and accuracy of seed sorting methods are key components of seed rain estimates in need of standardization. We propose and describe a standardized protocol for evaluating the effectiveness of two seed trap types (sticky and funnel traps) and the accuracy of a seed sorting method. We used widely available seeds (arugula, quinoa, sesame and sunflower) to produce a gradient of seed size, weight and colour. Proof-of-concept was tested in a tropical grassland, where traps were set for 30 days. Our results suggest that we underestimate dispersal of seeds with less than 2 mm width that can be easily mistaken for debris and soil particles or that fail to adhere to sticky traps. Seeds on sticky traps may be more vulnerable to removal by wind and rain, whereas seeds in funnel traps are more susceptible to decay. We found no evidence of observer bias on seed sorting for funnel trap samples. However, accuracy on seed sorting for funnel trap samples tended to decline for seeds with less than 2 mm width, suggesting a size-dependence in seed retrieval success. Our standardized protocol addressing trap effectiveness and seed sorting methods will increase the reliability of data obtained in seed rain studies and allow more reliable comparisons between datasets.

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Similarity between seed rain and neighbouring mature tree communities in an old-growth temperate forest

Journal of Forestry Research ◽

10.1007/s11676-019-01027-3 ◽

2019 ◽

Vol 31 (6) ◽

pp. 2435-2444

Author(s):

Yunyun Wang ◽

Jalene M. LaMontagne ◽

Fei Lin ◽

Zuoqiang Yuan ◽

Ji Ye ◽

...

Keyword(s):

Seed Dispersal ◽

Temperate Forest ◽

Community Dynamics ◽

Basal Area ◽

Seed Rain ◽

Mature Trees ◽

Data Set ◽

Deposition Patterns ◽

Tree Communities ◽

Tree Traits

Abstract Seed distribution and deposition patterns around parent trees are strongly affected by functional traits and therefore influence the development of plant communities. To assess the limitations of seed dispersal and the extent to which diaspore and neighbouring parental traits explain seed rain, we used a 9-year seed data set based on 150 seed traps in a 25-ha area of a temperate forest in the Changbai Mountain. Among 480,598 seeds belonging to 12 families, 17 genera, and 26 species were identified, only 54% of the species with mature trees in the community were represented in seeds collected over the 9 years, indicating a limitation in seed dispersal. Understory species were most limited; overstory species were least limited. Species with wind-dispersed seed had the least limitation, while the lowest similarity in species richness was for animal-dispersed species followed by gravity-dispersed species; fleshy-fruited species had stronger dispersal limitations than dry-fruited species. Generalized linear mixed models showed that relative basal area had a significant positive effect on seed abundance in traps, while the contribution of diaspore traits was low for nearly all groups. These results suggest that tree traits had the strongest contribution to seed dispersal and deposition for all functional groups examined here. These findings strengthen the knowledge that tree traits are key in explaining seed deposition patterns, at least at the primary dispersal stage. This improved knowledge of sources of seeds that are dispersed could facilitate greater understanding of seedling and community dynamics in temperate forests.

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Vegetation structure and greenness in Central Africa from Modis multi-temporal data

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0309 ◽

2013 ◽

Vol 368 (1625) ◽

pp. 20120309 ◽

Cited By ~ 43

Author(s):

Valéry Gond ◽

Adeline Fayolle ◽

Alexandre Pennec ◽

Guillaume Cornu ◽

Philippe Mayaux ◽

...

Keyword(s):

Vegetation Index ◽

Community Dynamics ◽

Regional Scale ◽

Congo Basin ◽

Deciduous Forests ◽

Environmental Drivers ◽

Vegetation Types ◽

Forest Types ◽

Evergreen Forests ◽

Multi Temporal

African forests within the Congo Basin are generally mapped at a regional scale as broad-leaved evergreen forests, with the main distinction being between terra-firme and swamp forest types. At the same time, commercial forest inventories, as well as national maps, have highlighted a strong spatial heterogeneity of forest types. A detailed vegetation map generated using consistent methods is needed to inform decision makers about spatial forest organization and their relationships with environmental drivers in the context of global change. We propose a multi-temporal remotely sensed data approach to characterize vegetation types using vegetation index annual profiles. The classifications identified 22 vegetation types (six savannas, two swamp forests, 14 forest types) improving existing vegetation maps. Among forest types, we showed strong variations in stand structure and deciduousness, identifying (i) two blocks of dense evergreen forests located in the western part of the study area and in the central part on sandy soils; (ii) semi-deciduous forests are located in the Sangha River interval which has experienced past fragmentation and human activities. For all vegetation types enhanced vegetation index profiles were highly seasonal and strongly correlated to rainfall and to a lesser extent, to light regimes. These results are of importance to predict spatial variations of carbon stocks and fluxes, because evergreen/deciduous forests (i) have contrasted annual dynamics of photosynthetic activity and foliar water content and (ii) differ in community dynamics and ecosystem processes.

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