Multiple equilibria in metapopulation dynamics

Hanski, Ilkka; Pöyry, Juha; Pakkala, Timo; Kuussaari, Mikko

doi:10.1038/377618a0

Cited by 140 publications

(104 citation statements)

References 23 publications

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“…The best examples are studies of various butter£y metapopulations. On the one hand, British butter£y populations do not show an obvious decline in spatial synchrony with distance (Sutcli¡e et al 1996), while on the other, Finnish butter£y populations display substantial asynchrony on a local scale, but seem to be synchronized over the entire metapopulation (Hanski et al 1995). There is also evidence of synchronous butter£y extinctions in response to single climatic events (Ehrlich et al 1980;Pollard & Yates 1993;Sutcli¡e et al 1996;Thomas et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Extinction dynamics and the regional persistence of a tree frog metapopulation

Carlson

Edenhamn

2000

Proc. R. Soc. Lond. B

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The concept of a metapopulation acknowledges local extinctions as a natural part of the dynamics of a patchily distributed population. However, if extinctions are not balanced by recolonizations or if there is a high degree of spatial synchrony of local extinctions, this poses a threat to and will reduce the metapopulation persistence time. Here we show that, in a metapopulation network of 378 pond patches used by the tree frog (Hyla arborea), even though extinctions are frequent (mean extinction probability p eˆ0 .24) they pose no threat to the metapopulation as they are balanced by recolonizations ( p cˆ0 .33). In any one year there was a pattern of large populations tending to persist while small populations became extinct. The total number of individuals belonging to populations that went extinct was small (5 5%) compared with those populations that persisted. A spatial autocorrelation analysis indicated no clustering of local extinctions. The tree frog metapopulation studied consisted of a set of larger, persistent populations mixed with smaller populations characterized by high turnover dynamics.

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Section: Discussionmentioning

confidence: 99%

Extinction dynamics and the regional persistence of a tree frog metapopulation

Carlson

Edenhamn

2000

Proc. R. Soc. Lond. B

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“…For many organisms, this pattern is exacerbated by decreases in population density with decreasing fragment area (Bowers & Matter, 1997 ;Connor et al, 2000), although for invertebrates such a simple generalisation cannot be made because of inconsistent results in the literature Matter, 2000;Steffan-Dewenter & Tscharntke, 2000;Krauss et al, 2003a). Irrespective of variability in the density-area relationship between species, small fragment area imposes a maximum limit on population size that leaves species vulnerable to local extinction (Lande, 1993;Hanski et al, 1995 ;Amarasekare, 1998 ;Burkey, 1999;Brook, Burgman & Frankham, 2000;Brook et al, 2002). The underlying mechanisms driving this relationship can be divided into four categories (Shaffer, 1981): (1) environmental stochasticity, (2) demographic stochasticity, (3) natural catastrophes and (4) reduced genetic diversity (see also review by .…”

Section: Isolationmentioning

confidence: 99%

Confounding factors in the detection of species responses to habitat fragmentation

2005

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Habitat loss has pervasive and disruptive impacts on biodiversity in habitat remnants. The magnitude of the ecological impacts of habitat loss can be exacerbated by the spatial arrangement -or fragmentation -of remaining habitat. Fragmentation per se is a landscape-level phenomenon in which species that survive in habitat remnants are confronted with a modified environment of reduced area, increased isolation and novel ecological boundaries. The implications of this for individual organisms are many and varied, because species with differing life history strategies are differentially affected by habitat fragmentation. Here, we review the extensive literature on species responses to habitat fragmentation, and detail the numerous ways in which confounding factors have either masked the detection, or prevented the manifestation, of predicted fragmentation effects.Large numbers of empirical studies continue to document changes in species richness with decreasing habitat area, with positive, negative and no relationships regularly reported. The debate surrounding such widely contrasting results is beginning to be resolved by findings that the expected positive species-area relationship can be masked by matrix-derived spatial subsidies of resources to fragment-dwelling species and by the invasion of matrix-dwelling species into habitat edges. Significant advances have been made recently in our understanding of how species interactions are altered at habitat edges as a result of these changes. Interestingly, changes in biotic and abiotic parameters at edges also make ecological processes more variable than in habitat interiors. Individuals are more likely to encounter habitat edges in fragments with convoluted shapes, leading to increased turnover and variability in population size than in fragments that are compact in shape. Habitat isolation in both space and time disrupts species distribution patterns, with consequent effects on metapopulation dynamics and the genetic structure of fragment-dwelling populations. Again, the matrix habitat is a strong determinant of fragmentation effects within remnants because of its role in regulating dispersal and dispersalrelated mortality, the provision of spatial subsidies and the potential mediation of edge-related microclimatic gradients.We show that confounding factors can mask many fragmentation effects. For instance, there are multiple ways in which species traits like trophic level, dispersal ability and degree of habitat specialisation influence specieslevel responses. The temporal scale of investigation may have a strong influence on the results of a study, with short-term crowding effects eventually giving way to long-term extinction debts. Moreover, many fragmentation effects like changes in genetic, morphological or behavioural traits of species require time to appear. By contrast, synergistic interactions of fragmentation with climate change, human-altered disturbance regimes, species interactions and other drivers of population decline may magnify the impacts...

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“…However, when scale or genetic diversity falls "too far," ecosystems or constituent species can tip downward into an alternate less desirable state, including the limiting (and absorbing) state of extinction. Environmental scientists have worked tirelessly at identifying and understanding thresholds in ecological systems in order that they might help resource managers avoid catastrophic collapse of biodiversity (13)(14)(15).…”

Section: Definitions and Conceptsmentioning

confidence: 99%

On biodiversity conservation and poverty traps

Barrett

Travis

Dasgupta

2011

Proc. Natl. Acad. Sci. U.S.A.

269

167

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This paper introduces a special feature on biodiversity conservation and poverty traps. We define and explain the core concepts and then identify four distinct classes of mechanisms that define important interlinkages between biodiversity and poverty. The multiplicity of candidate mechanisms underscores a major challenge in designing policy appropriate across settings. This framework is then used to introduce the ensuing set of papers, which empirically explore these various mechanisms linking poverty traps and biodiversity conservation.development | ecosystem | natural resources | sustainability | wildlife S temming biodiversity loss and reducing poverty are global challenges of the first order, enshrined in both the Convention on Biological Diversity and the Millennium Development Goals, agreed by virtually all countries over the past decade. The world is nonetheless struggling to meet the ambitions expressed in those global accords. The World Wide Fund for Nature International finds that the earth's wildlife populations have declined by a third over the past 35 y alone but by even more, 60%, in poorer tropical regions (1). The rate and magnitude of these losses will define the earth's sixth mass extinction period unless we quickly reverse this decline (2). Meanwhile, leaving aside the remarkable case of China, the number of people living in extreme poverty increased by more than 30% from 1981 to 2004 and now surpasses 1 billion (3).The persistence of extreme poverty and continued rapid loss of biodiversity appear intimately related. Extreme poverty and biodiversity hot spots are geographically coincident, concentrated in rural areas where livelihoods depend disproportionately on natural capital embodied in forests, rangelands, soils, water, and wildlife. Colocation naturally gives rise to closely coupled human-managed ecosystems that are in a precarious balance at best. Lack of resources, institutions, and governance structures often leaves local people illequipped to institute mechanisms to ensure long-term resource maintenance. Compounding this problem, the conditions of the human and nonhuman species within ecosystems coevolve in response to subtle shifts in any of several subsystems.Despite the importance of this coevolutionary relationship, connections between poverty traps and biodiversity conservation remain remarkably underexplored, not only in formal theorizing* but especially empirically. We have surprisingly little observational or experimental detail describing interactions in closely coupled human and natural systems in the rural tropics. In the absence of rigorous evidence on the synergies or tradeoffs between biodiversity conservation and escape from poverty traps, opinion and untested hypotheses predominate and crucial linkages are too often overlooked. Conservationists typically ignore the predictable consequences of human agency; people adapt behaviors in response to changes in environmental management, often generating unintended consequences that undermine conservation objectives (6). Simi...

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Multiple equilibria in metapopulation dynamics

Cited by 140 publications

References 23 publications

Extinction dynamics and the regional persistence of a tree frog metapopulation

Extinction dynamics and the regional persistence of a tree frog metapopulation

Confounding factors in the detection of species responses to habitat fragmentation

On biodiversity conservation and poverty traps

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