Study

Transient patterns in the assembly of vernal pool plant communities

  • Published source details Collinge S.K. & Ray C. (2009) Transient patterns in the assembly of vernal pool plant communities. Ecology, 90, 3313-3323

Actions

This study is summarised as evidence for the following.

Action Category

Excavate freshwater pools

Action Link
Marsh and Swamp Conservation

Introduce seeds of non-woody plants: freshwater wetlands

Action Link
Marsh and Swamp Conservation
  1. Excavate freshwater pools

    A replicated, site comparison study in 1998–2008 of 64 ephemeral pools on an air force base in California, USA (Collinge & Ray 2009) reported that excavated pools were colonized by five native, pool-characteristic plant species, but that these were less abundant than in nearby natural pools. Abundance of the five species peaked eight years after excavation, with a total frequency (summed across all species) of 5%. Over the eight years, individual species had a frequency of 0–21% in excavated pools, compared to 5–48% in nearby natural pools. Methods: In December 1999, sixty-four ephemeral pools were excavated in recently farmed grassland. The pools were 25–100 m2 and <150 m from natural pools. These pools were not sown with any seeds, but the surface was lightly raked. The frequency of five focal species (native species characteristic of Californian ephemeral pools) was recorded using grids of one hundred 2.5-cm2 cells. One grid was surveyed in some (number not specified) natural pools on the base in 1998 and 1999, and in each excavated pool in spring 2002–2008. This study was based on the same pools as (5).

    (Summarised by: Nigel Taylor)

  2. Introduce seeds of non-woody plants: freshwater wetlands

    A replicated, controlled, site comparison study in 1999–2008 in 256 excavated ephemeral pools on one air force base in California, USA (Collinge & Ray 2009) found that plots sown with seeds of five native, pool-characteristic herb species contained a greater abundance of these species than unsown plots. In seven of seven years, the combined frequency of the five pool-characteristic plants was greater in sown plots (3–19%) than unsown plots (<1–5%). The same was true in 30 of 35 comparisons for the individual species (sown: <1–44%; unsown: <0–21%). For comparison, the frequency of each species in nearby natural pools was 5–48%. Three of four analyzed species also strongly benefitted from “priority effects”: they were more frequent in pools where they were sown in the first year of the study than in pools where they were sown in the second year, after other species (see original paper for data). Methods: Between 1999 and 2001, seeds of five focal herb species (native species characteristic of Californian ephemeral pools) were sown onto 192 plots (each 0.25 m2 and in a separate excavated pool). Of these, 128 were sown with a mix of five species (600 seeds/plot, over 1–2 years) and 64 were sown with a single species (100–300 seeds/plot, over 1–3 years). The mixed-species plots received one of two planting orders (species A+B+C then species A+D+E, or species A+D+E then species A+B+C). Sixty-four additional plots (pools) were not sown. Each spring between 2002 and 2008, the frequency of the five focal species was recorded in each plot, using a grid of one hundred 2.5-cm2 cells. Some natural pools (number not specified) on the base were also surveyed in 1998 and 1999. This study was based on the same pools as (10).

    (Summarised by: Nigel Taylor)

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