Agroecosystems and Rangelands

Question 1

Agroecosystem

Answer 1

a conceptual construct used to describe a geographically and functionally coherent domain of agricultural activity (includes living and non-living components and interactions between them)

Question 2

agroecosystems services to agriculture

Answer 2

genetic resources
pest control
pollination
soil structure and fertility enhancement

Question 3

agroecosystem services from agriculture

Answer 3

provisioning services (food,fuel…), soil conservation, habitat provision

Question 4

agroecosystems disservices to agriculture

Answer 4

past damage
pathogen outbreaks
competion for resources

Question 5

agroecosystems disservices from agriculture

Answer 5

habitat degredation
soil degredation
water quality degredation

Question 6

agroecology

Answer 6

the application of ecological principles to agricultural systems and practices

Question 7

goals of agroecology

Answer 7

enhance ecosystem services through sustainable management of natural resources
reduce imputs to reduce costs and ecological footprint
increase value through social license

Question 8

weed control

Answer 8

continuous cover reduces barer ground for establishment
diverse crop rotations may increase competition for weeds
allelopathic plants may supress weeds

Question 9

pest supression

Answer 9

promoting predators and parasitoids can reduce pest outbreaks (reduce pest application, adjacent natural areas)
diverse cropping can dilute effects of species-specific pests

Question 10

How does diversity help grasslands be productive

Answer 10

inhances productivity in both dry and normal years
driven by presence of drought tolerant plants, increased soil organic matter, and drought resistant soil biota

Question 11

most ecosystems are _________ by ___________ in plant diversity

Answer 11

enhanced, increases

Question 12

What are grassland ecozones determined by?

Answer 12

precipitation (greatest effect) and temperature

Question 13

when do grasses first appear in the fossil record

Answer 13

55 MYA

Question 14

Major expansion of grasslands

Answer 14

happened worldwide between 4-7 MY ago
Tropical C4 grasslands become wiespread due to declining atmospheric CO2 levels and related diversification of C4 spp.

Question 15

co-evolution between grasses and grazers

Answer 15

many grasses have silica in cells, which makes them grainy. mammalian herbivores developed high crowned teeth to allow their teeth to grow as they wear down

Question 16

Grassland controlled fires

Answer 16

prevents encroachment of woody plants into grasslands. Fire return intervals can be very short

Question 17

How are grassland plants fire resistant?

Answer 17

perennial plants keppmost nutrients and essential organs belowground. As long as it doesnt get really hot, they will just grow right back

Question 18

How many hectares of grasslands are converted to farmland?

Answer 18

23 million

Question 19

range health

Answer 19

the ability of rangelads to maintain function and services

Question 20

rangeland services

Answer 20

forage for livestock and wildlife
wildlife habitat
carbon sequestration
soil conservation

Question 21

how is range health assessed in Saskatchewan

Answer 21

species composition
vegetation structure
invasive species
site/soil stability
hydrological function and soil protection

Question 22

tools to maintain range health

Answer 22

appropriate stocking rates
rotational grazing
prescribed fire
invasive plant management