Human Impact on Resources, Biodiversity, and Ecosystems

Types of Resources natural resources – goods and services provided for by nature renewable resources – replaced naturally in a reasonable amount of time non-renewable resources commons – resources owned by everyone

tragedy of the commons renewable common resources which tend to be over-exploited Why? “if I don’t use them then someone else will so it might as well be me”

exploitation of resources carrying capacity – the maximum size of a population that can be supported over the long term maximum sustainable yield (MSY) – the greatest “use” of a renewable resource

Human Impact on Biodiversity species biodiversity – the total number of different kinds of species genetic biodiversity – the total gene pool for a given species biosphere biodiversity – the total number of species in existence - known species: 2 million - unknown species: 3 – 50 million

Value of Biodiversity Why should we care about protecting other species? Food agriculture and meat production has led to a decline in species biodiversity as well as genetic biodiversity Medicine many modern medicines come from plant extracts * biopiracy

Value of Biodiversity cont. ecosystem sustainability the greater the biodiversity, the greater the stability * keystone species commercial value - ecotourism - recreation; hunting, fishing, wildlife watching - timber intrinsic value preservationist philosophy – existence of other species has value aside from any use we make of it

HIPPO

Human Causes of Biodiversity Decline habitat destruction deforestation, wetlands destruction, development introduction of exotic species most introduced species do not survive their new habitat – those that do, often out-compete native species (and are termed invasive)

human causes continued … overuse (hunting, fishing) * poaching pollution * climate change

Reduced Ranges Indian Tiger Range 100 years ago Range today (about 2,300 left) Fig. 9-8a, p. 191

Reduced Ranges Black Rhino Range in 1700 Range today (about 2,400 left) Fig. 9-8b, p. 191

Deliberately Introduced Species Purple looselife European starling African honeybee (“Killer bee”) Nutria Salt cedar (Tamarisk) Marine toad Water hyacinth Japanese beetle Hydrilla European wild boar (Feral pig) Fig. 9-11a, p. 193

Accidentally Introduced Species Sea lamprey (attached to lake trout) Argentina fire ant Brown tree snake Eurasian muffle Common pigeon (Rock dove) Formosan termite Zebra mussel Asian long-horned beetle Asian tiger mosquito Gypsy moth larvae Fig. 9-11b, p. 193

Kudzu Fig. 9-12, p. 194

Fire Ant Invasion 1918 2000 Fig. 9-13, p. 195

Extinction Threats from Poaching Profits of poaching Causes of poaching: food, fur, pets, traditional medicines, trophies, eliminating pests, etc. Bushmeat Illegal pets and decorative plants

Bushmeat Fig. 9-15, p. 196

Confiscated Products From Endangered Species Fig. 9-18, p. 199

Extinction Threats from Climate Change and Pollution Global Warming Pesticide threats DDT biomagnification (bioaccumulation)

Biomagnification of DDT DDT in fish-eating birds (ospreys) 25 ppm DDT in large fish (needle fish) 2 ppm DDT in small fish (minnows) 0.5 ppm DDT in zooplankton 0.04 ppm DDT in water 0.000003 ppm, or 3 ppt Fig. 9-16, p. 197

Litter Kills Seals Fig. 9-19, p. 200

Extinction background extinction rate - naturally occurring extinctions - 99 % of all species are now extinct local extinction extinction of a population but not an entire species species extinction - disappearance of an entire species - criteria for claiming this? mass extinction 5 major episodes of extinction in Earth’s past

Extinction Crisis Question the species-area relationship lose 50% of a habitat, lose 15% of the biodiversity found there fragmentation and edge effect carving up a habitat into several smaller pieces increases edge habitat, decreases interior habitat and results in a loss of biodiversity interior species, edge species

Fragmentation Cleared plots for grazing Highway Cleared plots for agriculture Fig. 8-10b, p. 161

Case Study: Amazonia satellite images are used to measure species loss – How? deforestation rate is slower than originally thought however, the pattern of deforestation (fragmentation) may be causing a faster loss of species primary (old growth) vs. secondary forests (less biodiversity)

Strategies for Protecting Biodiversity laws and treaties - CITES Convention on International Trade of Endangered Species - MMPA Marine Mammal Protection Act - ESA Endangered Species Act endangered, threatened, special concern captive breeding, zoos, game parks, cloning

Protecting Marine Biodiversity why do we use preservation techniques with some species (whales) and conservation techniques with other species (fish)? part of protecting biodiversity involves measuring populations and migratory patterns – how is that done with whales?

Case Study: Whale Preservation conservation vs. preservation commercial whaling IWC 1986 commercial whaling ban scientific whaling subsistence whaling

Study of Whales fluke prints satellite tags captivity