×

UPSC Courses

DNA banner

DAILY NEWS ANALYSIS

GS-III :
  • 29 July, 2020

  • 5 Min Read

Source-sink dynamics

Source-sink dynamics

  • Source–sink dynamics is a theoretical model used by ecologists to describe how variation in habitat quality may affect the population growth or decline of organisms.
  • Since quality is likely to vary among patches of habitat, it is important to consider how a low quality patch might affect a population.
  • In this model, organisms occupy two patches of habitat.
  1. One patch, the source, is a high quality habitat that on average allows the population to increase.
  2. The second patch, the sink, is a very low-quality habitat that, on its own, would not be able to support a population.
  • However, if the excess of individuals produced in the source frequently moves to the sink, the sink population can persist indefinitely. Organisms are generally assumed to be able to distinguish between high and low-quality habitat and to prefer high-quality habitats.
  • However, the ecological trap theory describes the reasons why organisms may actually prefer sink patches over source patches.
  • Finally, the source-sink model implies that some habitat patches may be more important to the long-term survival of the population, and considering the presence of source-sink dynamics will help inform conservation decisions.
  • Recently tiger surveys in India has shown the tiger population in the source-sink in the ratio of 60:40. 33% of the tiger population in India lives outside its source i.e, tiger reserves.
  • It moves towards the sink due to a decline in the capacities of the tiger reserves to further hold the tiger population. 17/50 tiger reserves in India are going to achieve its maximum capacity to holf the tiger populations.

Ecological traps

  • Ecological traps are scenarios in which rapid environmental change leads organisms to prefer to settle in poor-quality habitats.
  • The concept stems from the idea that organisms that are actively selecting habitat must rely on environmental cues to help them identify high-quality habitat.
  • If either the habitat quality or the cue changes so that one does not reliably indicate the other, organisms may be lured into poor-quality habitat.
  • Ecological traps are thought to occur when the attractiveness of a habitat increases disproportionately in relation to its value for survival and reproduction.
  • The result is preference of falsely attractive habitat and a general avoidance of high-quality but less-attractive habitats.

For example, Indigo buntings typically nest in shrubby habitat or broken forest transitions between closed canopy forest and open field. Human activity can create 'sharper', more abrupt forest edges and buntings prefer to nest along these edges. However, these artificial sharp forest edges also concentrate the movement of predators which predate their nests. In this way, Buntings prefer to nest in highly altered habitats where their nest success is lowest

Source: TH/WIKI


India–Azerbaijan

A year after tensions arising from Operation Sindoor, India and Azerbaijan have taken steps to restore and normalise bilateral relations. The 6th round of Foreign Office Consultations, held in Baku, marked the first such engagement since 2022, signaling renewed diplomatic momentum. Recent Diplomatic Engagement During the consultations, bo

India–Australia Economic Cooperation and Trade Agreem

The India–Australia Economic Cooperation and Trade Agreement has completed four years since its signing. Both countries now aim to build on this progress through strengthened collaboration and ambitious targets, including reaching AUD 100 billion in bilateral trade by 2030. What is the India–Australia Economic Cooperation and Tra

ADR Report on Political Funding

A recent report by the Association for Democratic Reforms (ADR) analyses donations of ?20,000 or more declared to the Election Commission of India (ECI) by national political parties for FY 2024–25, highlighting transparency and accountability in political financing. Key Findings Massive Funding Surge Total donations to nationa

Maritime Chokepoints

Maritime chokepoints are narrow channels along global shipping routes where maritime traffic is concentrated. These points are geopolitically and economically critical, as they handle a large proportion of global trade, especially energy shipments. Current Relevance Over two-thirds of seaborne energy trade passes through a handful o

US-Israel-Iran War

Following the launch of Operation Epic Fury (U.S.) and Operation Roaring Lion (Israel), the geopolitical landscape has shifted fundamentally with the confirmed death of Iran’s Supreme Leader, Ayatollah Ali Khamenei.Iran retaliated through Operation True Promise 4, launching missile attacks against Israel and nearby Gulf states. The escala

DNA

05 Apr,2026

Toppers

Search By Date

Newsletter Subscription
SMS Alerts

Important Links

UPSC GS Mains Crash Course - RAW