scholarly journals Habitat percolation transition undermines sustainability in social-ecological agricultural systems

2021 ◽  
Author(s):  
Diego Bengochea Paz ◽  
Kirsten Henderson ◽  
Michel Loreau
Keyword(s):  
Population Size ◽  
Human Population ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
Natural Habitat ◽  
Agricultural Expansion ◽  
Percolation Transition ◽  
Effective Measure ◽  
Landscape Degradation ◽  
Social Ecological

Steady increases in human population size and resource consumption are driving rampant agricultural expansion and intensification. Habitat loss caused by agriculture puts the integrity of ecosystems at risk, and threatens the persistence of human societies that rely on ecosystem services. We develop a spatially explicit model describing the coupled dynamics of an agricultural landscape and human population size to study the effect of different land-use management strategies, defined by agricultural clustering and intensification, on the sustainability of the social-ecological system. We show how agricultural expansion can cause natural habitat to undergo a percolation transition leading to abrupt habitat fragmentation that feedbacks on human's decision making, aggravating landscape degradation. We found that agricultural intensification to spare land from conversion is a successful strategy only in highly natural landscapes, and that clustering agricultural land is the most effective measure to preserve large connected natural fragments, avoid severe fragmentation, and thus, enhance sustainability.

scholarly journals Habitat percolation transition undermines sustainability in social-ecological agricultural systems

2021 ◽  
Author(s):  
Diego Bengochea Paz ◽  
Kirsten Henderson ◽  
Michel Loreau
Keyword(s):  
Population Size ◽  
Habitat Loss ◽  
Human Population ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
Agricultural Landscapes ◽  
Agricultural Expansion ◽  
Percolation Transition ◽  
Effective Measure ◽  
Social Ecological

Steady increases in human population size and resource consumption levels are driving rampant agricultural expansion and intensification in some of the world’s most pristine ecosystems. Habitat loss caused by agriculture puts the integrity of ecosystems at risk, and as a consequence, threatens the persistence of human societies that rely on ecosystem services to produce resources. Here we develop a spatially explicit model describing the coupled dynamics of an agricultural landscape and human population size to study the effect of different land-use management strategies, defined by the levels of agricultural clustering and intensification, on the sustainability of the social-ecological system. We show how gradual agricultural expansion can cause natural habitat to undergo a percolation transition leading to abrupt habitat fragmentation that feedbacks on human’s decision making, causing faster agricultural expansion and aggravating habitat loss and fragmentation. We found that agricultural intensification to spare land from conversion is a successful strategy only in highly natural landscapes and that clustering agricultural land is the most effective measure to preserve landscape connectivity and avoid severe fragmentation. Our work highlights the importance of preserving large connected natural fragments in agricultural landscapes to enhance sustainability.

Global agricultural expansion

2017 ◽  
Author(s):  
Jonathan R. B. Fisher
Keyword(s):  
Land Use ◽  
Population Growth ◽  
Human Population ◽  
Agricultural Land ◽  
Natural Habitat ◽  
Agricultural Land Use ◽  
Agricultural Expansion ◽  
Global Trends ◽  
The World ◽  
National Trends

This chapter asks whether evidence supports the widely held belief that land used for agriculture around the world has continued to rapidly expand via conversion of natural habitat in response to the demands created by recent human population growth. Contrary to conventional wisdom, global agricultural land use peaked in 1998 and has since declined. While habitat continues to be cleared for agriculture, on a global net basis, more agricultural land has been converted to other uses than vice versa. This analysis also found that national trends in agricultural expansion are driven by factors other than population growth. Although this does not mean agriculture is “sustainable,” these findings challenge the dominant narrative around global agricultural expansion and highlight other important issues that must be addressed. Looking at data at national and subnational scales is essential to understand the implications of global trends in agriculture, where improvements and interventions are most needed.

scholarly journals Time-delayed biodiversity feedbacks and the sustainability of social-ecological systems

2017 ◽  
Author(s):  
A.-S. Lafuite ◽  
M. Loreau
Keyword(s):  
Ecosystem Services ◽  
Technological Change ◽  
Population Size ◽  
Demographic Transition ◽  
Human Population ◽  
Ecological Systems ◽  
Land Conversion ◽  
Social Ecological Systems ◽  
Social Ecological

AbstractThe sustainability of coupled social-ecological systems (SESs) hinges on their long-term ecological dynamics. Land conversion generates extinction and functioning debts, i.e. a time-delayed loss of species and associated ecosystem services. Sustainability theory, however, has not so far considered the long-term consequences of these ecological debts on SESs. We investigate this question using a dynamical model that couples human demography, technological change and biodiversity. Human population growth drives land conversion, which in turn reduces biodiversity-dependent ecosystem services to agricultural production (ecological feedback). Technological change brings about a demographic transition leading to a population equilibrium. When the ecological feedback is delayed in time, some SESs experience population overshoots followed by large reductions in biodiversity, human population size and well-being, which we call environmental crises. Using a sustainability criterion that captures the vulnerability of an SES to such crises, we show that some of the characteristics common to modern SESs (e.g. high production efficiency and labor intensity, concave-down ecological relationships) are detrimental to their long-term sustainability. Maintaining sustainability thus requires strong counteracting forces, such as the demographic transition and land-use management. To this end, we provide integrative sustainability thresholds for land conversion, biodiversity loss and human population size - each threshold being related to the others through the economic, technological, demographic and ecological parameters of the SES. Numerical simulations show that remaining within these sustainable boundaries prevents environmental crises from occurring. By capturing the long-term ecological and socioeconomic drivers of SESs, our theoretical approach proposes a new way to define integrative conservation objectives that ensure the long-term sustainability of our planet.

scholarly journals GMSE: an R package for generalised management strategy evaluation

2017 ◽  
Author(s):  
A. Bradley Duthie ◽  
Jeremy J. Cusack ◽  
Isabel L. Jones ◽  
Jeroen Minderman ◽  
Erlend B. Nilsen ◽  
...  
Keyword(s):  
Management Strategy ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
R Package ◽  
List Type ◽  
Management Scenarios ◽  
Management Strategy Evaluation ◽  
Social Ecological ◽  
Strategy Evaluation ◽  
Key Aspects

AbstractManagement strategy evaluation (MSE) is a powerful tool for simulating all key aspects of natural resource management under conditions of uncertainty.We present the R package GMSE, which applies genetic algorithms to provide a generalised tool for simulating adaptive decision-making management scenarios between stakeholders with competing objectives under complex social-ecological interactions and uncertainty.GMSE models can be agent-based and spatially explicit, incorporating a high degree of realism through mechanistic modelling of links and feedbacks among stakeholders and with the ecosystem; additionally, user-defined sub-models can also be incorporated as functions into the broader GMSE framework.We show how GMSE simulates a social-ecological system using the example of an adaptively managed waterfowl population on an agricultural landscape; simulated waterfowl exploit agricultural land, causing conflict between conservation interests and the interest of food producers maximising their crop yield.The R package GMSE is open source under GNU Public License; source code and documents are freely available on GitHub.

scholarly journals Remarkable Population Resilience in a North African Endemic Damselfly in the Face of Rapid Agricultural Transformation

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 353
Author(s):  
Rassim Khelifa ◽  
Hayat Mahdjoub ◽  
Affef Baaloudj ◽  
Robert A. Cannings ◽  
Michael J. Samways
Keyword(s):  
Land Cover ◽  
Agricultural Land ◽  
Large Population ◽  
Agricultural Practices ◽  
Agricultural Expansion ◽  
North African ◽  
Natural Habitats ◽  
Agricultural Transformation ◽  
The Face ◽  
Terrestrial Habitats

Agriculture can be pervasive in its effect on wild nature, affecting various types of natural habitats, including lotic ecosystems. Here, we assess the extent of agricultural expansion on lotic systems in Northern Africa (Algeria, Tunisia, and Morocco) and document its overlap with the distribution of an endemic damselfly, Platycnemis subdilatata Selys, using species distribution modeling. We found that agricultural land cover increased by 321% in the region between 1992 and 2005, and, in particular, the main watercourses experienced an increase in agricultural land cover from 21.4% in 1992 to 78.1% in 2005, together with an increase in the intensity of 226% in agricultural practices. We used capture–mark–recapture (CMR) surveys in terrestrial habitats surrounding a stream bordered by grassland and cropland in northeastern Algeria to determine demographic parameters and population size, as well as cropland occupancy. CMR modeling showed that the recapture and survival probabilities had an average of 0.14 (95%CI: 0.14–0.17) and 0.86 (0.85–0.87), respectively. We estimated a relatively large population of P. subdilatata (~1750 individuals) in terrestrial habitats. The occupancy of terrestrial habitats by adults was spatially structured by age. Our data suggest that P. subdilatata has survived agricultural expansion and intensification better than other local odonate species, mainly because it can occupy transformed landscapes, such as croplands and grasslands.

scholarly journals A Place-Based Approach to Agricultural Nonmaterial Intangible Cultural Ecosystem Service Values

2020 ◽  
Vol 12 (2) ◽  
pp. 699 ◽  
Author(s):  
Joy R. Petway ◽  
Yu-Pin Lin ◽  
Rainer F. Wunderlich
Keyword(s):  
Land Cover ◽  
Ecosystem Service ◽  
Agricultural Landscape ◽  
Agricultural Land ◽  
Environmental Data ◽  
Farming Practices ◽  
Environmental Characteristics ◽  
Cultural Ecosystem Service ◽  
Context Specific ◽  
Landscape Biodiversity

Though agricultural landscape biodiversity and ecosystem service (ES) conservation is crucial to sustainability, agricultural land is often underrepresented in ES studies, while cultural ES associated with agricultural land is often limited to aesthetic and tourism recreation value only. This study mapped 7 nonmaterial-intangible cultural ES (NICE) valuations of 34 rural farmers in western Taiwan using the Social Values for Ecosystem Services (SolVES) methodology, to show the effect of farming practices on NICE valuations. However, rather than a direct causal relationship between the environmental characteristics that underpin ES, and respondents’ ES valuations, we found that environmental data is not explanatory enough for causality within a socio-ecological production landscape where one type of land cover type (a micro mosaic of agricultural land cover) predominates. To compensate, we used a place-based approach with Google Maps data to create context-specific data to inform our assessment of NICE valuations. Based on 338 mapped points of 7 NICE valuations distributed among 6 areas within the landscape, we compared 2 groups of farmers and found that farmers’ valuations about their landscape were better understood when accounting for both the landscape’s cultural places and environmental characteristics, rather than environmental characteristics alone. Further, farmers’ experience and knowledge influenced their NICE valuations such that farm areas were found to be sources of multiple NICE benefits demonstrating that farming practices may influence ES valuation in general.

Plasma vitellogenin in male teleost fish from 43 rivers worldwide is correlated with upstream human population size

2010 ◽  
Vol 158 (10) ◽  
pp. 3279-3284 ◽  
Author(s):  
Jean-Pierre W. Desforges ◽  
Brendan D.L. Peachey ◽  
Pauline M. Sanderson ◽  
Paul A. White ◽  
Jules M. Blais
Keyword(s):  
Population Size ◽  
Teleost Fish ◽  
Human Population

A semi-hybrid model for malaria with limited superinfection

1998 ◽  
Vol 30 (04) ◽  
pp. 1027-1057 ◽  
Author(s):  
Philippe Picard
Keyword(s):  
Stochastic Model ◽  
Population Size ◽  
Hybrid Model ◽  
Human Population ◽  
Threshold Level ◽  
The Other ◽  
The Difference ◽  
The One

Modelling malaria with consistency necessitates the introduction of at least two families of interconnected processes. Even in a Markovian context the simplest fully stochastic model is intractable and is usually transformed into a hybrid model, by supposing that these two families are stochastically independent and linked only through two deterministic connections. A model closer to the fully stochastic model is presented here, where one of the two families is subordinated to the other and just a unique deterministic connection is required. For this model a threshold theorem can be proved but the threshold level is not the one obtained in a hybrid model. The difference disappears only when the human population size approaches infinity.

scholarly journals Evaluation of dog population in an urban area of Southeastern Brazil

1997 ◽  
Vol 31 (3) ◽  
pp. 308-309 ◽  
Author(s):  
Cáris M. Nunes ◽  
Dejanira de A. Martines ◽  
Stélios Fikaris ◽  
Luzia H. Queiróz
Keyword(s):  
Population Size ◽  
Urban Area ◽  
Human Population ◽  
Total Population ◽  
Southeastern Brazil ◽  
Control Programs ◽  
Paulo State ◽  
Vaccination Campaigns ◽  
Rabies Vaccination ◽  
Size And Structure

Planning control programs, for diseases such as rabies requires information on the size and structure of the dog and cat population. In order to evaluate the dog population of the urban area of Araçatuba city, S. Paulo State, Brazil, a survey was conducted using a questionnaire to interview members of households. Eighty-eight districts were visited (37,778 houses) and the interview was possible at 77.93% of these. Human population size evaluated was 113,157 inhabitants. Houses that owned animals represented 55.2%, 26,926 of the animals concerned were dogs and 5,755 were cats. Of the dogs, 56.64% were 1-4 year olds and males represented 56.2% of the total population. Dog: person ratio was estimated at 2.8 dogs to every 10 persons, almost 3 times the ratio hitherto estimated and used in the planning of rabies vaccination campaigns.

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