A Method for Monitoring Long‐Term Population Trends: An Example Using Rare Arctic‐Alpine Plants

Lesica, Peter; Steele, Brian M.

doi:10.2307/2269491

Cited by 17 publications

(13 citation statements)

References 37 publications

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“…1991). This approach has been used to account for the multivariate nature of the data (site × year) using data collected from repeated measurements on the same experimental plots (Kent & Coker 1992; Guo & Brown 1996; Lesica & Steele 1996). Richness data were square root ( x + 0.5) and density data log ( x + 1) transformed prior to analysis.…”

Section: Methodsmentioning

confidence: 99%

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Morgan

2001

Journal of Ecology

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1 Seedling recruitment was followed from 1993 to 1996 in four remnant Themeda triandra grassland sites in south-eastern Australia subjected to different long-term fire histories (1-, 2-, 4-year fire intervals, unburnt > 10 years). Multivariate analyses were used to separate the effects of site and year on recruitment and community dynamics. 2 Exotic species (mostly annual monocots such as Aira spp., Briza minor and Juncus capitatus ) dominated the seedling flora at all sites in all years. Seedlings of most native species were absent or rare in all years, despite their abundance in the standing flora. 3 Seedling recruitment (richness and density) in the long unburnt grassland was significantly less than in burnt sites in all years. Hence, the seedling floristic composition of this site was substantially different from all other sites on PCA axis 1, which did not differ in all years. 4 Amongst burnt sites, some differences in the annual seedling cohort were evident on PCA axes 2 and 3, but these were due to small differences in the relative abundance rather than the composition of recruiting species. Seedling recruitment was not cued or promoted by fire but rather, seedling density was influenced by, and interacted with, yearly (presumably rainfall) variation. 5 Amongst the native species seen as seedlings, yearly emergence occurred in some cases (14 of 24 species) but always at low densities (< 10 seedlings/0.25 m 2 ). Seedling survival amongst native species varied from nil (0%) to high (> 60%), with most mortality occurring in early summer. 6 The temporal and spatial variation observed in seedling regeneration suggests that long-term native species coexistence may be promoted by differences in the 'regeneration niche'. Seedling regeneration, however, has minimal impact on the short-term dynamic of this community, whose conservation requires maintenance of the existing 'bud-and tuber-bank' of native species.

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Section: Methodsmentioning

confidence: 99%

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Morgan

2001

Journal of Ecology

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“…Long-term trends in species abundances are often obscured by short-term £uctuations (Lesica & Steele, 1996) and for this reason, it is di⁄cult to interpret the observed changes.…”

Section: Species'changes After 45 Yearsmentioning

confidence: 99%

Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores

et al. 2005

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An historical data set, collected in 1958 by Southward and Crisp, was used as a baseline for detecting change in the abundances of species in the rocky intertidal of Ireland. In 2003, the abundances of each of 27 species was assessed using the same methodologies (ACFOR [which stands for the categories: abundant, common, frequent, occasional and rare] abundance scales) at 63 shores examined in the historical study.Comparison of the ACFOR data over a 45-year period, between the historical survey and re-survey, showed statistically signi¢cant changes in the abundances of 12 of the 27 species examined. Two species (one classed as northern and one introduced) increased signi¢cantly in abundance while ten species (¢ve classed as northern, one classed as southern and four broadly distributed) decreased in abundance. The possible reasons for the changes in species abundances were assessed not only in the context of anthropogenic e¡ects, such as climate change and commercial exploitation, but also of operator error. The error or di¡erences recorded among operators (i.e. research scientists) when assessing species abundance using ACFOR categories was quanti¢ed on four shores. Signi¢cant change detected in three of the 12 species fell within the margin of operator error. This e¡ect of operator may have also contributed to the results of no change in the other 15 species between the two census periods. It was not possible to determine the e¡ect of operator on our results, which can increase the occurrence of a false positive (Type 1) or of a false negative (Type 2) outcome.

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“…Hence, alpine plants are considered to be sensitive to climate warming (Lesica & Steele, 1996;Kö rner, 2003). This assumption is supported by an increasing number of observational studies (Walther et al, 2002;Walther, 2003).…”

Section: Introductionmentioning

confidence: 99%

Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA^* master site Schrankogel, Tyrol, Austria

Pauli

Gottfried

Reiter

et al. 2006

Global Change Biology

419

356

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High mountain ecosystems are defined by low temperatures and are therefore considered to react sensitively to climate warming. Responding to observed changes in plant species richness on high peaks of the European Alps, an extensive setup of 1 m Â 1 m permanent plots was established at the alpine-nival ecotone (between 2900 and 3450 m) on Mount Schrankogel, a GLORIA master site in the central Tyrolean Alps, Austria, in 1994. Recording was repeated in a representative selection of 362 quadrats in 2004. Ten years after the first recording, we observed an average change in vascular plant species richness from 11.4 to 12.7 species per plot, an increase of 11.8% (or of at least 10.6% at a 95% confidence level). The increase in species richness involved 23 species (about 43% of all taxa found at the ecotone), comprising both alpine and nival species and was pronouncedly higher in plots with subnival/nival vegetation than in plots with alpine grassland vegetation. Only three species showed a decrease in plot occupancy: one was an annual species, one was rare, and one a common nival plant that decreased in one part of the area but increased in the uppermost part. Species cover changed in relation to altitudinal preferences of species, showing significant declines of all subnival to nival plants, whereas alpine pioneer species increased in cover. Recent climate warming in the Alps, which has been twice as high as the global average, is considered to be the primary driver of the observed differential changes in species cover. Our results indicate an ongoing range contraction of subnival to nival species at their rear (i.e. lower) edge and a concurrent expansion of alpine pioneer species at their leading edge. Although this was expected from predictive distribution models and different temperature-related habitat preferences of alpine and nival species, we provide first evidence on -most likely -warming-induced species declines in the high European Alps. The projected acceleration of climate warming raises concerns that this phenomenon could become the major threat to biodiversity in high mountains.

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A Method for Monitoring Long‐Term Population Trends: An Example Using Rare Arctic‐Alpine Plants

Cited by 17 publications

References 37 publications

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores

Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA^* master site Schrankogel, Tyrol, Austria

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A Method for Monitoring Long‐Term Population Trends: An Example Using Rare Arctic‐Alpine Plants

Cited by 17 publications

References 37 publications

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Seedling recruitment patterns over 4 years in an Australian perennial grassland community with different fire histories

Using historical data to detect temporal changes in the abundances of intertidal species on Irish shores

Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA* master site Schrankogel, Tyrol, Austria

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Signals of range expansions and contractions of vascular plants in the high Alps: observations (1994–2004) at the GLORIA^* master site Schrankogel, Tyrol, Austria