A 200-year perspective on alternative stable state theory and lake management from a biomanipulated shallow lake

Climate sets the potential biomass of trees and physiologists have made considerable progress in understanding and predicting that potential and applying it in global vegetation models. The problem is in understanding and predicting tree cover where it is far from the climate potential. Vast areas of non-forested vegetation occur where climates are suitable for forests. Arguments over why forests are absent, ongoing for over a century, are generally polarized between favouring bottom-up factors (resource constraints) or top-down factors (herbivory, predation, fire). There is increasing support for hypotheses invoking the interaction between the two. This chapter introduces the key hypotheses, their assumptions and predictions. Trophic ecology is a useful framework for exploring departures from the climate potential for trees, focussing explicitly on regulation by consumers, including fire. Alternative stable state theory is emerging as particularly appropriate for explaining forest/non-forest mosaics with each state maintained by positive feedbacks to the preferred environment.

Download Full-text

Different coastal marsh sites reflect similar topographic conditions for bare patches and vegetation recovery

10.5194/esurf-2020-56 ◽

2020 ◽

Author(s):

Chen Wang ◽

Lennert Schepers ◽

Matthew L. Kirwan ◽

Enrica Belluco ◽

Andrea D'Alpaos ◽

...

Keyword(s):

Stable State ◽

Venice Lagoon ◽

State Theory ◽

Sediment Supply ◽

Coastal Marsh ◽

Tidal Range ◽

Unstable State ◽

Stable States ◽

Alternative Stable State ◽

Subsequent Loss

Abstract. The presence of bare patches within otherwise vegetated coastal marshes is sometimes considered to be a symptom of marsh die-back and the subsequent loss of important ecosystem services. Here we studied the topographical conditions determining the presence and revegetation of bare patches in three marsh sites with contrasting tidal range, sediment supply and plant species: the Scheldt Estuary (the Netherlands), Venice Lagoon (Italy), and Blackwater Marshes (Maryland, USA). We analyzed topographic properties of bare patches, including elevation, size, distance and connectivity to channels based on GIS analyses of aerial and LIDAR imagery. Our results demonstrate that across the different marsh sites, bare patches connected to channels occur most frequently at the lowest elevations and farthest distance from the main channels. Bare patches disconnected from channels occur most frequently at intermediate elevations and distances from channels, and vegetated marshes dominate at highest elevations and shortest distances from channels. Revegetation in bare patches is observed in only one site with the highest tidal range and highest sediment availability, and preferentially occurs from the edges of small unconnected bare patches at intermediate elevations and intermediate distances from channels. Our results are discussed within the alternative stable state theory. We suggest the existence of two stable states, a high-elevated vegetated state close to channels that tends to remain high and vegetated, and a low-elevated state of bare connected patches far from channels that tends to remain bare, with an unstable state at intermediate channel distances where bare patches may form and rapidly become revegetated.

Download Full-text

Large herbivores suppress liana infestation in an African savanna

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2101676118 ◽

2021 ◽

Vol 118 (41) ◽

pp. e2101676118

Author(s):

Tyler C. Coverdale ◽

Ryan D. O’Connell ◽

Matthew C. Hutchinson ◽

Amanda Savagian ◽

Tyler R. Kartzinel ◽

...

Keyword(s):

Stable State ◽

Life Forms ◽

Tree Canopy ◽

Alternative Stable State ◽

African Savanna ◽

Large Herbivore ◽

Large Herbivores ◽

Woody Vines ◽

Plant Life Forms ◽

Canopy Area

African savannas are the last stronghold of diverse large-mammal communities, and a major focus of savanna ecology is to understand how these animals affect the relative abundance of trees and grasses. However, savannas support diverse plant life-forms, and human-induced changes in large-herbivore assemblages—declining wildlife populations and their displacement by livestock—may cause unexpected shifts in plant community composition. We investigated how herbivory affects the prevalence of lianas (woody vines) and their impact on trees in an East African savanna. Although scarce (<2% of tree canopy area) and defended by toxic latex, the dominant liana, Cynanchum viminale (Apocynaceae), was eaten by 15 wild large-herbivore species and was consumed in bulk by native browsers during experimental cafeteria trials. In contrast, domesticated ungulates rarely ate lianas. When we experimentally excluded all large herbivores for periods of 8 to 17 y (simulating extirpation), liana abundance increased dramatically, with up to 75% of trees infested. Piecewise exclusion of different-sized herbivores revealed functional complementarity among size classes in suppressing lianas. Liana infestation reduced tree growth and reproduction, but herbivores quickly cleared lianas from trees after the removal of 18-y-old exclosure fences (simulating rewilding). A simple model of liana contagion showed that, without herbivores, the long-term equilibrium could be either endemic (liana–tree coexistence) or an all-liana alternative stable state. We conclude that ongoing declines of wild large-herbivore populations will disrupt the structure and functioning of many African savannas in ways that have received little attention and that may not be mitigated by replacing wildlife with livestock.

Download Full-text

Path-dependent institutions drive alternative stable states in conservation

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1806852116 ◽

2018 ◽

Vol 116 (2) ◽

pp. 689-694 ◽

Cited By ~ 9

Author(s):

Edward W. Tekwa ◽

Eli P. Fenichel ◽

Simon A. Levin ◽

Malin L. Pinsky

Keyword(s):

Renewable Resources ◽

Path Dependence ◽

Alternative Stable States ◽

Stable State ◽

Empirical Support ◽

Stable States ◽

Alternative Stable State ◽

Important Challenge ◽

Quantitative Analyses ◽

Path Dependent

Understanding why some renewable resources are overharvested while others are conserved remains an important challenge. Most explanations focus on institutional or ecological differences among resources. Here, we provide theoretical and empirical evidence that conservation and overharvest can be alternative stable states within the same exclusive-resource management system because of path-dependent processes, including slow institutional adaptation. Surprisingly, this theory predicts that the alternative states of strong conservation or overharvest are most likely for resources that were previously thought to be easily conserved under optimal management or even open access. Quantitative analyses of harvest rates from 217 intensely managed fisheries supports the predictions. Fisheries’ harvest rates also showed transient dynamics characteristic of path dependence, as well as convergence to the alternative stable state after unexpected transitions. This statistical evidence for path dependence differs from previous empirical support that was based largely on case studies, experiments, and distributional analyses. Alternative stable states in conservation appear likely outcomes for many cooperatively managed renewable resources, which implies that achieving conservation outcomes hinges on harnessing existing policy tools to navigate transitions.

Download Full-text

The long-term changes in food web structure and ecosystem functioning of a shallow lake: Implications for the lake management

Journal of Environmental Management ◽

10.1016/j.jenvman.2021.113804 ◽

2022 ◽

Vol 301 ◽

pp. 113804

Author(s):

Xiaoxin Zhang ◽

Yujun Yi ◽

Zhifeng Yang

Keyword(s):

Food Web ◽

Shallow Lake ◽

Ecosystem Functioning ◽

Lake Management ◽

Food Web Structure ◽

Web Structure ◽

Long Term Changes

Download Full-text

Mesocosm experiment reveals a strong positive effect of snail presence on macrophyte growth, resulting from control of epiphyton and nuisance filamentous algae: Implications for shallow lake management

The Science of The Total Environment ◽

10.1016/j.scitotenv.2019.135958 ◽

2020 ◽

Vol 705 ◽

pp. 135958 ◽

Cited By ~ 4

Author(s):

Liu Yang ◽

Hu He ◽

Baohua Guan ◽

Jinlei Yu ◽

Zongbao Yao ◽

...

Keyword(s):

Shallow Lake ◽

Lake Management ◽

Mesocosm Experiment ◽

Filamentous Algae ◽

Macrophyte Growth ◽

Positive Effect

Download Full-text

The alternative stable state concept and the management of Apennine mountain ponds

Aquatic Conservation Marine and Freshwater Ecosystems ◽

10.1002/aqc.749 ◽

2005 ◽

Vol 15 (6) ◽

pp. 625-634 ◽

Cited By ~ 8

Author(s):

Antonio Ruggiero ◽

Angelo G. Solimini ◽

Gianmaria Carchini

Keyword(s):

Stable State ◽

Alternative Stable State

Download Full-text

Too much, too soon? A review of the effects of increasing wildfire frequency on tree mortality and regeneration in temperate eucalypt forests

International Journal of Wildland Fire ◽

10.1071/wf15010 ◽

2016 ◽

Vol 25 (8) ◽

pp. 831 ◽

Cited By ~ 75

Author(s):

Thomas A. Fairman ◽

Craig R. Nitschke ◽

Lauren T. Bennett

Keyword(s):

Tree Mortality ◽

Stable State ◽

Alternative Stable State ◽

Juvenile Period ◽

Eucalypt Forest ◽

Eastern Australia ◽

State Changes ◽

State Models ◽

Eucalypt Forests ◽

In Fire

In temperate Australia, wildfires are predicted to be more frequent and severe under climate change. This could lead to marked changes in tree mortality and regeneration in the region’s predominant eucalypt forests, which have been burned repeatedly by extensive wildfires in the period 2003–14. Recent studies have applied alternative stable state models to select ‘fire sensitive’ forest types, but comparable models have not been rigorously examined in relation to the more extensive ‘fire tolerant’ forests in the region. We review the effects of increasing wildfire frequency on tree mortality and regeneration in temperate forests of Victoria, south-eastern Australia, based on the functional traits of the dominant eucalypts: those that are typically killed by wildfire to regenerate from seed (‘obligate seeders’) and those that mostly survive to resprout (‘resprouters’). In Victoria, over 4.3 million ha of eucalypt forest has been burned by wildfire in the last decade (2003–14), roughly equivalent to the cumulative area burned in the previous 50 years (1952–2002; 4.4 million ha). This increased wildfire activity has occurred regardless of several advancements in fire management, and has resulted in over 350 000 ha of eucalypt forest being burned twice or more by wildfire at short (≤11 year) intervals. Historical and recent evidence indicates that recurrent wildfires threaten the persistence of the ‘fire sensitive’ obligate seeder eucalypt forests, which can facilitate a shift to non-forest states if successive fires occur within the trees’ primary juvenile period (1–20 years). Our review also highlights potential for structural and state changes in the ‘fire tolerant’ resprouter forests, particularly if recurrent severe wildfires kill seedlings and increase tree mortality. We present conceptual models of state changes in temperate eucalypt forests with increasing wildfire frequency, and highlight knowledge gaps relating to the development and persistence of alternative states driven by changes in fire regimes.

Download Full-text