Question

how did horseshoe crab and red knot system that is undergoing upgrading after being downgraded due to human alteration of the trophic structure?

Answer 1

The Red knots are a group of birds that travels from tropical and temperate conditions in the winter all the way to the Arctic for breeding.During their migration,The horseshoe crabs near the Delware bay is a chief souce of food for these birds.The eggs of the horse shoe crabs provide a rich diet to the red knot birds.This is important for the birds to attain enough health and energy to survive the harsh conditions of the artic.The eggs have rich lipid content and are so an easy and nutrient rich source of food

Human intervention and harvesting of the crabs in large quantities for various purposes such as baiting, medical research and development caused a rapid decline in the crab population. Horseshoe crabs were harvested for the antibacterial properties of their blood , for the hemocyanin pigment which is a copper based oxygen transporter and also for the  Amebocytes in them which are fast reacting.This caused a rapid decline in the population.

The climatic changes affected the breeding of the horseshoe crabs. The mating of the crabs depend upon the lunar cycles,temperature,wave action etc..Due to the rise in water temperature and changes in the wave patterns the mating time of the crabs changes and thus there occured a mismatch betwen the visiting times of the redknot and the mateing of the crabs.This lead to non availibility of the eggs.This indeed affected the Redknot population and they declined in their numbers.