What led to the dramatic decline in the biodiversity of agricultural crop species?

The decline in biodiversity led to habitat degradation: conversion, fragmentation, intrusion, simplification and also, pollution, invasive species, climate change, over hunting or overgrazing. Habitat degradation fragmentation which people conquered landscape makes geometrically organized reinforcements that often contrast highly with neighboring patches. The predisposition is to shrink the size of forest parcels. Habitat degradation simplification which decrease biodiversity and human use of habitats simplifies them which taking fallen logs for firewood could be removing a habitat that several microscopic species depend on. Tree diversity deterioration when a forest is coped for a specific species of a tree. Channelizing streams decreases the diversity of fish and invertebrates. Habitat degradation conversion which natural zones are transformed to farms, housing subdivisions, malls, marinas, and industrial centers and habitat degradation intrusion which wind mills, telephone polls, lights attract birds that migrate at night and kill them and between 5 and 50 million killed.