Natural Disturbances and Early Successional Habitats

White, Peter S.; Collins, Beverly; Wein, Gary

doi:10.1007/978-94-007-1620-9_3

Cited by 10 publications

(5 citation statements)

References 31 publications

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“…Rarely studied, however, is how pre-disturbance forest spatial patterns, including advance regeneration and the former overstory, influence the structure of post-disturbance stands. Although disturbances may be severe enough to erase pre-disturbance structural patterns [ 5 , 13 ], recent studies show persistent horizontal patterns after disturbances [ 6 , 8 ], and that such fidelity of pattern can persist for more than two centuries [ 14 – 15 ]. However, the drivers underlying this continuity of pattern and the consequences for early-seral stand structure and development are poorly understood.…”

Section: Introductionmentioning

confidence: 99%

Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

et al. 2015

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BackgroundSevere canopy-removing disturbances are native to many temperate forests and radically alter stand structure, but biotic legacies (surviving elements or patterns) can lend continuity to ecosystem function after such events. Poorly understood is the degree to which the structural complexity of an old-growth forest carries over to the next stand. We asked how pre-disturbance spatial pattern acts as a legacy to influence post-disturbance stand structure, and how this legacy influences the structural diversity within the early-seral stand.MethodsTwo stem-mapped one-hectare forest plots in the Czech Republic experienced a severe bark beetle outbreak, thus providing before-and-after data on spatial patterns in live and dead trees, crown projections, down logs, and herb cover.ResultsPost-disturbance stands were dominated by an advanced regeneration layer present before the disturbance. Both major species, Norway spruce (Picea abies) and rowan (Sorbus aucuparia), were strongly self-aggregated and also clustered to former canopy trees, pre-disturbance snags, stumps and logs, suggesting positive overstory to understory neighbourhood effects. Thus, although the disturbance dramatically reduced the stand’s height profile with ~100% mortality of the canopy layer, the spatial structure of post-disturbance stands still closely reflected the pre-disturbance structure. The former upper tree layer influenced advanced regeneration through microsite and light limitation. Under formerly dense canopies, regeneration density was high but relatively homogeneous in height; while in former small gaps with greater herb cover, regeneration density was lower but with greater heterogeneity in heights.ConclusionThese findings suggest that pre-disturbance spatial patterns of forests can persist through severe canopy-removing disturbance, and determine the spatial structure of the succeeding stand. Such patterns constitute a subtle but key legacy effect, promoting structural complexity in early-seral forests as well as variable successional pathways and rates. This influence suggests a continuity in spatial ecosystem structure that may well persist through multiple forest generations.

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Section: Introductionmentioning

confidence: 99%

Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

et al. 2015

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“…Increasing suppression of disturbance regimes, particularly fire, has altered species composition, and therefore trait expression (Nowacki & Abrams, ). Forests in the US are largely comprised of stands <100 years old following broad agricultural abandonment in the 20th century (White et al., ). Combined with continuous anthropogenic stressors such as a habitat fragmentation, urbanization, N deposition and climate change, this may mean disturbance characteristics are altered.…”

Section: Discussionmentioning

confidence: 99%

“…Second, different disturbance types (e.g. fire vs ice storm) variably impact forest understories where seedling communities exist (White et al., ). Certain disturbances may have high survivorship of pre‐disturbance seedlings that would continue to contribute to a RWM post‐disturbance, thereby masking the trait signal of new recruits.…”

Section: Discussionmentioning

confidence: 99%

“…In mature forest communities, light is the predominant limiting resource as mature trees form a closed canopy, reducing light at the ground level by as much as 99% (Canham, Finzi, Pacala, & Burbank, 1994). This asymmetric light competition limits the performance of seedlings and saplings, and forest disturbances that remove tree biomass promote species diversity across landscapes by increasing access to light and promoting the recruitment of disturbance-dependent species (White, Collins, & Wein, 2011). Recasting categories such as 'disturbance-dependent' into quantitative functional traits allows for more mechanistic inferences of the processes underlying community responses to disturbance (Mouillot, Graham, Villéger, Mason, & Bellwood, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Functional trait shifts after disturbance reveal broad‐scale variability in temperate forest regional recruitment processes

Wilfahrt

2018

J Vegetation Science

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Question Decreased above‐ground biomass and subsequent changes in resource availability exert a strong influence on seedling recruitment in post‐disturbance forests. Ecological trade‐offs underlie recruitment processes, as species vary in resource allocation, dispersal and stress tolerance strategies. Functional traits that indicate resource acquisition–conservation trade‐offs include leaf N content, wood density, maximum height, shade tolerance and drought tolerance, while seed mass can indicate species’ dispersal strategies. This study looks for generality in post‐disturbance trait responses, and asks whether these responses are additionally constrained or amplified by disturbance characteristics, climate and ecological provinces. Location Eastern US temperate forests. Methods I leveraged a longitudinal, continental‐scale database of post‐disturbance forests to examine recruitment dynamics. Using multivariate, hierarchical Bayesian models, I examined how disturbance affects the traits of seedling layer communities where recruitment dynamics should be most evident, and compared this to undisturbed communities. I also examined how the traits underlying trade‐off axes varied across disturbance properties, ecological provinces and climatic gradients. Results All traits except leaf N showed significant, study‐wide shifts in disturbed communities consistent with expectations of post‐disturbance stands. In undisturbed plots, all traits had significant shifts in the opposite direction to those observed in disturbed plots, except leaf N and drought tolerance, where no change was observed. Disturbance severity increased the magnitude of response of several, but not all, trait responses in disturbed plots. The traits that had significant shifts were idiosyncratic across ecological provinces, indicating unique processes influencing disturbance responses across the system. Moreover, while climate strongly correlated with all traits prior to disturbance in the initial sampling periods, it was not correlated with disturbance responses. Conclusions This study demonstrates general, biome‐wide trait shifts towards resource acquisition and bet‐hedging dispersal strategies in post‐disturbance forest seedling communities. At finer spatial scales, the traits underlying these trade‐offs varied, indicating that disturbance‐dependent species differ in life‐history strategies across the system. This variation across ecological provinces appears independent of temperature and precipitation, suggesting that unmeasured abiotic or biotic variables influence recruitment. Seedling recruitment is critical in shaping future adult tree communities, and this study reveals large‐scale contingencies in trait patterns associated with this process.

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“…Forest disturbances maintain and drive successional changes in species composition [1], and are known to impact the strength of forest carbon sinks [2,3], hydrologic dynamics [4,5], and nutrient cycling and retention [6,7]. Further, disturbance from insect and pathogen outbreaks, drought, and fire may be increasing in frequency and severity due to changes in climate [8,9].…”

Section: Introductionmentioning

confidence: 99%

Patch-Based Forest Change Detection from Landsat Time Series

Hughes

Kaylor

Hayes

2017

Forests

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Abstract:In the species-rich and structurally complex forests of the Eastern United States, disturbance events are often partial and therefore difficult to detect using remote sensing methods. Here we present a set of new algorithms, collectively called Vegetation Regeneration and Disturbance Estimates through Time (VeRDET), which employ a novel patch-based approach to detect periods of vegetation disturbance, stability, and growth from the historical Landsat image records. VeRDET generates a yearly clear-sky composite from satellite imagery, calculates a spectral vegetation index for each pixel in that composite, spatially segments the vegetation index image into patches, temporally divides the time series into differently sloped segments, and then labels those segments as disturbed, stable, or regenerating. Segmentation at both the spatial and temporal steps are performed using total variation regularization, an algorithm originally designed for signal denoising. This study explores VeRDET's effectiveness in detecting forest change using four vegetation indices and two parameters controlling the spatial and temporal scales of segmentation within a calibration region. We then evaluate algorithm effectiveness within a 386,000 km 2 area in the Eastern United States where VeRDET has overall error of 23% and omission error across disturbances ranging from 22% to 78% depending on agent.

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Natural Disturbances and Early Successional Habitats

Cited by 10 publications

References 31 publications

Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

Legacy of Pre-Disturbance Spatial Pattern Determines Early Structural Diversity following Severe Disturbance in Montane Spruce Forests

Functional trait shifts after disturbance reveal broad‐scale variability in temperate forest regional recruitment processes

Patch-Based Forest Change Detection from Landsat Time Series

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