BIOL214Z Ecology - Mick Hanley [1]

Question 1

What is Ecology?

Answer 1

Krebs (1972) defined it as “the scientific study of the processes regulating the distribution and abundance of organisms and the interactions among them”

Question 2

Define population

Answer 2

A group of individuals of a single species that live in a particular area and interact with one another.

Question 3

Define community

Answer 3

An association of populations of different species in the same area.

Question 4

Define Ecosystem

Answer 4

A community of organisms plus their physical environment.

Question 5

Ecology can be studied at which 2 scales?

Answer 5

Spatial and temporal

Question 6

Why is biodiversity important?

Answer 6

Food security
Medicine
Life support

Question 7

How can biodiversity improve food security?

Answer 7

Wild crop plant ecotypes offer a rich genetic diversity to protect commercial varieties, so maintaining genetic biodiversity is very important to combat threats like diseases.

Question 8

What is Ecosystem Function

Answer 8

the capacity of natural processes and components to provide goods and services that satisfy human needs directly or indirectly

Question 9

What are Ecosystem Services

Answer 9

Provides a way to identify economically important aspects of biodiversity.

Question 10

Large blue butterfly study
(a conservation umbrella)

Answer 10

spitzer et al (2009)

-intricate predatory relationship with ants (Myrmica)

-UK pop wiped out by infrasture and lack of sheep grazing

-Comparing species richness in different areas (occupied, unoccupied and third)

-166 sites, carpathian chain czech republic

-Zig-Zag walk method with semi quantified abundance scale

-Redundancy analysis- vegetation to butterflys

• western slopes- highest butterfly number shows higher vegetation unbundance/ and species

Question 11

Ecosystem values paper
(making decisions)

Answer 11

Wallace (2007)

-Paper discusses classification of ecosystems services that provide a framework for decisions in natural resource management

• Tackles current problems with classification and builds a consistent logic
• types of service:
  Provisioning (food, fibre, water)
  regulating (air quality reg, climate)
  cultural (spiritual/religion, ecotourism)
  Supporting (photosynthesis, soil formation)

-Key fullfillments:
Adequate resources (ex- nutricious food snd enough of it
protection from predators, disease, parasites (low enough threat)
Benign physical and chemical enviroment
Socio/cultural fulfilement

Conclusion- underpin effective natural resource decisions, including trade-offs. However, the above discussion has shown that it is essential to clearly separate means (processes) and ends (services) when classifying ecosystem services.
And that socio/cultural enviroments arent a 1 fit all category

Question 12

Portfolio effect/ functional groups

Answer 12

diversification of species doing different things in different ways= stability

Question 13

Sampling effect

Answer 13

more species equals a higher chance a competitive species will use resources better and stop invasability

Question 14

Complementarity

Answer 14

each species occupies a niche so no space for invasion

Question 15

invasives:

definitions
characteristics
invasion concepts
ecosystem processes

Answer 15

a global phenomenon- influence in human transport across the globe

australian species growing in south africa and being a major pest species over there. Futhermore european species cause disruption in australia

Question 16

semantics (pest species term)

Answer 16

pest= any organsim that humans equates to be of a newsence value. Transmit diseases, compete for food etc. But still could be native.

non-native or alien species- a species growing outside of its native range, could arrive by deliberate or accident.

invasive species-any non-native organism that affects the habitats they invade

Question 17

Housefly:
pest species

Answer 17

common pest around human habitation
100 pathogen species, worms, typhoid, chollera.

their feeding method: vectoring pathogens

land on food, their saliva from their guts, partly digest externally and then suck this back up digestive liquid. Great vector for travelling things in and out of the fly, and through depositing faeces due ot high ingestion rates.

native to europe but just a pest

Question 18

Sycamore tree
example of non-native/alien

Answer 18

middle ages introduction: can colonise rapidly (helicoptering seeds). Traditionally seen asa threat to woodland biodiverty due to its colonisation ability.

But it supports a range of novel species. Such as epiphytes, herbivores and ground flora.

Is it an accident they didnt get a chance to re-invade because of the landbridge, between britian and europe closure due to the last ice age?

Question 19

invasive species:
silver carp

Answer 19

much be charcaterised by having a environmental or eclogical impact.

Introduded to europe from asia as an attempt to control algal growth, from euthropication.

high population grown capacity

varacious appetite: 40 times own body weight in a day, distrubt the plankton-based food chain

getting closer to the great lake system, this holds 20% of global freshwater.

Question 20

invasive species definition:

Answer 20

any non-native species with adverse economic environmental or ecological impacts

Question 21

characteristics of invasive species

what makes an effective invasive species?

weeds example

Answer 21

good coloniser of disturbed ground, respond to distrubance ( often human activity)

genetic variation- can take advantage of many different environmental situations can take advantage of lots of environmental scenarios

variation within indivduals- grown and flowering highly plastic (within the indivudal adaptable to the environmental scenario) and can adapt to the situation that they are in specifically

highly fecund (lots of seeds) high dispersive, and seeds can lay dormant until right situation occurs- this could be through disturbance.

vegetative reproduction (water hyersynth) small plants detatching and forming their own smaller colony

toxicity to grazers and other plants- secrete chemicals that will effect other plant species

Question 22

weed species map on to life history strat and resource allocation?

Question 23

round goby-
rapid population spread through europe and into north america, originally native to brackish water near the caspian sea. Natural change to behaviour and biology.

Started to invade freshwater (dnieper) populations

Brown & Stepien (2009 Molecular Ecology)

https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1365-294X.2008.04014.x

Answer 23

can move on its own as well as ships ballast. (human involvement)
shipping to north america, baltic sea.

can move on its own as well as human involvemnet. Individuals are highly plastic…they can tollerate lots of different water conditions (brackish to fresh). Thus giving the species the ability to move quickly

substantial genetic variation that was enchancced in the states by multiple founding populations

high fecund (lots of eggs) and male show nest-guarding behaviour.
Adult fish also tend to eat other fish eggs to outcompete.

study:
We analyse its genetic diversity and divergence patterns among 25 North American (N = 744) and 22 Eurasian (N = 414) locations using mitochondrial DNA cytochrome b gene sequences and seven nuclear microsatellite loci in order to: (i) identify the invasion’s founding source(s), (ii) test for founder effects, (iii) evaluate whether the invasive range is genetically heterogeneous, and (iv) determine whether fringe and central areas differ in genetic diversity

live fast, die young, be adaptable, dont get eaten

Question 24

round goby:
paper showed comparison between laods in native and north american goby populations

https://bioone.org/journals/journal-of-vertebrate-biology/volume-70/issue-4/jvb.21050/Non-native-gobies-share-predominantly-immature-parasites-with-local-fish/10.25225/jvb.21050.full

Answer 24

shows a similar trend to the flowers.
fish from great lakes had fewer parasites then native range-fish (ERH)

EICA- not yet demo in animals

Question 25

invasion concepts
models to show how the characterstics map on ecologically to the rapid spread in new environments

Question 26

Enemy release hypothesis

example
carpenter & cappuccino (2005)
https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2745.2005.00973.x

Answer 26

any introduced species (out of its native range) have been removed from normal predators such as pathogens or herbivore control. Therefore they are free from natural controls

a decrease in regulations by natural enemies resulting in increased distribution potential and abundance in new habitats.

carpenter & cappuccino.

We tested the enemy release hypothesis for invasiveness using field surveys of herbivory on 39 exotic and 30 native plant species growing in natural areas near Ottawa, Canada, and found that exotics suffered less herbivory than natives.
showed that non-native suffered less herbivory then plants ranked as less invasive.

Invasion potential and being attacked by native herbivores show, show a pos correalation

Question 27

EICA Hypothesis

i.e. the Evolution of Increased Competitive Ability

less represented as it takes a long time to monitor:
https://www.researchgate.net/publication/222192817_Comparison_of_life_history_traits_between_invasive_and_native_populations_of_purple_loosestrife_Lythrum_salicaria_using_nonlinear_mixed_effects_model

Answer 27

comes from plant defence theory.

plant defence theory suggets that poorly defended by fast growing genotypes should be most favoured if herbiory is reduced.
evolution should choose for ability to grow quickly and reproduction not plant defence.

Eica: less represented as it takes a long time. Some hints at a shift in adaptive traits

joshi & tielborger (2012)
compared plant size and susceptibility to herbivory in native european and introduced north american loosestrife populations

plants grown in common conditions in germany- the north american variety grew larger as expected because putting resources into plant growth instead of herbivore defence.
Thus the na showed more herbivory then european. Rapid resource aquisitation and reduced herbiovore defence

Question 28

kvach and stepien

compared parasite loads in native and north american goby populations

Answer 28

fish from the great lakes had fewer parasites then the native fish (ERH)

evidence that enemy release hypothesis is occuring.

EICA not yet demonstrated in animals

Question 29

conceptial models allow:

characteristics displayed by non native with the potential the species have to establish and become pests in this new area.
invasive potential reinforced by the escape of their natural enemys (ERH)

free from natural enemies so now can work on EICA and becoming more competitive in this new area

Question 30

ecological impacts

Answer 30

numerous examples in the literature where the introduction of a species to a new region causes the decline or loss of native species.

-competiton, exploitation

Question 31

subtle interactions:

invasion meltdown

Answer 31

the process by which the negative impacts induced on native ecosystems by one or more non-indigenous species are exaggerated by interactions with another species.

Question 32

lack et al
example of invasion impacts

Answer 32

ants (technomyrmex albipes)
were introduced to to indian island ocnea.

the ant deters attacks on the native plant ( leucaena) its main herbivore (decrease in plant growth and seed produciton when the ants are excluded).

native plant (taccada)- the ants aid the herbivore by protecting sap-suckling bugs from predation
(therefore removal of ants aids plant growth)

conclusions:
ants protect invasives plants but main herbivores but exacerbates the effects of herbivory on the native.
thus helping the non native plant species (leucaena) further invade into the enviornment

Question 33

look at honey bees in australia.

invasion meltdown: mechanism that shows disruption.

Facilliate pollination of invasive weed species. As these non native honey bees facilitate their pollination

Question 34

topics covered so far:

-predator prey
-island biogeography theory
-tropic structuring
- trait expression

-defined invasive species and characteristics
- how and why they spread theories
-ecosystem services that could be effected.

Question 35

sheehy et al 2018
exposure to predation by recovering pine martens is highly asymmetrial.

shared enemies

Answer 35

Pine martens (looks like a stout) find it harder to predate smaller Red squirrels (they can get to smaller branches)
Reduced Grey numbers free’s Reds from resource competition and reduces infection by squirrelpox virus

Question 36

habitat loss:
habitats & ecosystem services
pollinator decline & loss
halting pollinator decline

Answer 36

global habitat loss: greatest loss of biodiversity

80% of land service has been transformed by human activity
60% of earths ecosystems are seen as degraded.
(mea 2005) shows this- grasslands and woodlands highly affected

loss of habitat on ecosystem services- reduces provisioning and cultural services.

Loss of mangrove habitat (1/3 pre industrial) of mangroves since 1980-

*vital for coastal protection root systems good for wave attenuation (storm energy taken out by tangeled web of moangrove roots) sediments trapping abilty, nutrient cycling, carbon sequestration, habitat for fish species (nursery)

estimated $1.billion of ecosystem services provison is provided by mangrove habitat (therefore this money would be needed to restore this)

Question 37

key habitats
(costanza et al)
for ES

Answer 37

25% loss- tropical forest value: $3.8 trillion for raw materials, c-sequest, genetic resources. Old estimates.

30% loss- sea grass beds: nutrient cycling, wave attenuation, fish nursery= $3.8 trillion (costanza et al)

25%- sand dunes: sediment supply, wave attenuation, recreation for human well being.
Lose sediment supply in one area, loss in another.

Question 38

shifts in habitat that has effected pollinator servcie provision.

global pollinator crisis?
(bees)

*Gallai et al (2009 Ecological Economics 68: 810–821)

https://www.sciencedirect.com/science/article/pii/S0921800908002942

Answer 38

the decline in bumble bee diversity and abundance linked to habitat loss together.
As well as changes in the management of honey bee colonies and diseases.

why does a lack of pollinators matter?
Essential for crop production:
crop production (bean, fruit family, wild flower) all used to set seed, thus produce crop
ES= $153 bil (2005)

allied services also at risk

Economic valuation of the vulnerability of world agriculture confronted with pollinator decline:

1) the contribution of insect pollination to the world agricultural output economic value,

2) the vulnerability of world agriculture in the face of pollinator decline. We used a bioeconomic approach, which integrated the production dependence ratio on pollinators, for the 100 crops used directly for human food worldwide as listed by FAO.

Question 39

increased used to nenicotinoids and pesticide use could be the reason for pollinator decline?-

pesticides
watch lecture
wwwyoutube.com/watch?v=WDkpVWzFnK0

Whitehorn et al 2012 Science 336: 351-352

Answer 39

Neonicotinoid insecticides have been implicated in these declines because they occur at trace levels in the nectar and pollen of crop plants. We exposed colonies of the bumble bee Bombus terrestris in the laboratory to field-realistic levels of the neonicotinoid imidacloprid, then allowed them to develop naturally under field conditions. Treated colonies had a significantly reduced growth rate and suffered an 85% reduction in production of new queens compared with control colonies. Given the scale of use of neonicotinoids, we suggest that they may be having a considerable negative impact on wild bumble bee populations across the developed world.

Question 40

chemical imputs on pollinator abudance and diversity

plymouth study:
compared bumblebee abundance either side of arable hedgerows

Answer 40

Hanley & Wilkins (2015) compared bumblebee abundance either side of arable hedgerows

in devon and cornwall- margins facing the roadside tended to have a higher level of bees present. Then the margins that faced the crop.

Road facing tend to have more flowers and more flowering species.
Red campion (mean abundance) is more common on the road facing side then crop facing (an important pollinator)

herbicides also favour for fast growing chemical imputs fertilliser use tends to favour fast growing species like grasses and nettles etc the hedgerow creates a barrier between the flowers and the pesticides

Question 41

How changes in farming methods since WW2 have effected pollinators:

-increase in pesticidges
-cultivation of silage,
loss of 97% of flower rich meadows

76% reduction in bumble bee forage since 1978. Less hedgerows therefore no nesting capabilities.

Answer 41

https://besjournals.onlinelibrary.wiley.com/doi/10.1111/j.1365-2664.2006.01249.x
paper:
Comparing the efficacy of agri-environment schemes to enhance bumble bee abundance and diversity on arable field margins

Question 42

importance of forage

goulson et al (2005)
specialist feeding

Answer 42

certain bumblebees are fussy eaters and rely on specific species to feed on.b.humils-92% members of the facaeae (pea family)
large preference for fabaceae

Question 43

fabacea specalists only collect pollen from these sorts species:

-fabaceae and similar looking flowers with high protein content

hanley et al (2008 functional ecology)
species like red clover, have high protein levels (30%) and the loss of meadows have effected plant species.

Question 44

lepidoptera (other pollinators) also declined.

uk moth species linked to habitat loss, increased use of pesticides again.

fox et al (2013)

Answer 44

study looked at micromoth species from meta data spanning from 1970’s to now to register abundance.

260 declined, 160 increased.
most species associated with low nitrogen and open environments decreased.

Question 45

how do you stop the decline?
land use options

Answer 45

agri-environment schemes (AES)
provide finacial incentives to farmers

3 levels (entry, organic, higher)
farmers can enter ecological stringent cerfitication schemes to aid pollinator provision
(www.conservationgrade.org)

AES options include:

EF4/OEFA:
small strips of pollen and nectar flower rich areas

EB1-2/OEB1-2: reduced cutting
enhanced hedgerow management.

To facility less disturbance to nesting and hybernating bumble bees

Question 46

higher level ESS grassland options

Answer 46

HK6- maintain existing spaces (paying farmers for good practice)

HK7-restoration former species rich to new semi-natural

HK8- creation of semi natural grassland from scratch

Question 47

how good are AES options at encouraging pollinators?

(carvel et al, 2007)

Answer 47

legume- based seeds

EF4-blocks of flowering rich areas within fields- produce many more flowers and brought more pollinators

EF3- late season mix provided earlier and later vital forage resources. Have to think about their life history prospects. As they need forage to start out
(stresses the impotance of seasonal flowering in the flower rich strips)

schemes are benefical to bumble bees but not necessarily other pollinators.

Question 48

reviewing ESS options

Answer 48

schemes have benefical to bumblebees but not any other species

many authors have reviewed ESS
some say there was no inpacts on bee/wasps and others say consevation grade schemes are better then AES

Question 49

mass flowering crops to the rescue?

Answer 49

oilseed rape comprises 11% in UK of land space.
Field beans take 4% both crops present flower rich resources for 2 to 3 weeks
(an important mass floral resource for pollinating insects)

bumblebee abundace in germany?
oil seed rape and bumblebee abundance

westphal et al (2003)
found that bumble density was greater in areas containing oilseed rape

herrmann et al (2007)
suggested increased nest size linked to Mass Flower Crop cultivation

Question 50

visits along transects:

plymouth undergrad:
visits from bees adjacent to MFC (bean) field margins. But only during the flowering times

Answer 50

recorded more bumble bees in hedgerows closer to bean flowering period but only for that amount of time.

Question 51

bioenergy crops (BECS)
dont produce useable pollinating crop but are much more flower rich. Are attracted to the foraging outputs and somewhere to live.

willow, poplar, miscanthus (grass)- dont create useable pollen and nectar through the year but are much more flower rich.

berkely et al

therefore strategic planting for ES?

Answer 51

likey that bees are attarcted the BECs for forage and hibernation/nesting sites

Question 52

reviewed:
*how habitat loss effects habitats and ES
*Focussing on pollinator decline
*focused on way to change land use/land use pollicy
*provide suitable habitat through the schemes- need to consdier hedgerow provision as well as flowering strips. So it takes into accoutn bee, moths

*cultivate more mass energy/bioenergy crops for pollinators

Question 53

over exploitation:

-pleistocene overkill
-megafauna and the ecosystem
-apex predators
-conservation issues to consider with rewilding

Question 54

anthropogenic exploitation

Answer 54

exploitation of biodiversity isnt new.

Large herbivores (mega fauna were globally common until 11k bp)
now only in saharan africa.

Question 55

malhi et al (2016)

shows the extent of mega fauna loss across the continent.

Location of mega- herbs and where they are still extant
data consistently show, although their have been species loss in africa. Most species have still faired better there

Question 56

overkill?

Answer 56

many debates if ovr exploitation has attributed to mega fauna death.
Where anthropogentic or climate change causes.

example:
9 moa species in new zealand have gone extinct, due to human hunting and habitat change. 600 years ago. (flightless bird species)

Question 57

pleistocene overkill and ecosystem processes.

heterogeneity they would have created:

Answer 57

*over exploitation by humans has a signifcant role in their demise.

*consuming large amounts of vegetation

*soil disturbance

• redistributing nutrients

*affecting behaviours of other animals

Question 58

mega fauna thrive in africa

they evolved in tandem with hominid species

only 2/44 sub-saharan genera have gone extinct since the ice age

Answer 58

african savannah- combination of open grassland and acacia thickets.

this is maintained by a combination of fire and grazing. Elephants are a keystone species

Question 59

the acacia cycle

Answer 59

first dispersed by elephants in their dung, most samplings are killed by fire and herbivory.

After a while the acacia will be consumed to the point where theres nothing left to burn and they will slowly start to be able to reform.

ungulates forced to migrate and look else where

once stablished in the absence of their predators, the growth of saplings can be rapid (reaching a metre tall within a month) been fertilised by the dung

spinesence develops which aids fire retardancy… thus aiding plant development under the thickets

elephants then return:
migrating elephants will mow down the entire area of even aged thickets. Pushing over to eat the green leaves at the top of the canopy.

smaller ungulate species then return to repress acacia development further

Question 60

elephants are savannah engineers
their absence would change the nature of the ecosystem greatly.

Therefore intermediate disturbance hypothesis comes into play

Answer 60

thickets vs grassland
as a consequence of light vs shade demanding grasses

elephant activity also effect ungulate behaviour.
many of them activly avoid thickets and prefer open grassland areas.
As predators use thickers as cover to smbush prey.

Question 61

complex interactions

so besides their direct effect on plant communities they are also effecting predator prey interactions

Question 62

predators impact on ecosystems

Answer 62

wolves in scotland: high deer densities with a cobination of sheep grazing theirs a big shift in tree composition

Question 63

return of wolves to yellowstone

Answer 63

wolves were hunted to extinction in 1920’s

*return in mid 1990’s. Immediate effect on deer populations and their foraging behaviour.

*browsing areas declined and tree height increased.

*increase in aspen height along rivers as predators have a better chance here, tken to higher up the valley on hills

Question 64

Further impacts

Answer 64

lots of tree species increased

other herbivore species such as bison also increased as they dont experience as much competition

Question 65

tropic cascases example

birds also increase )perching bird species)
as increase in tree growth and cover

thus showing the impact of over exploitation on biodiversiy

Question 66

rewilding

suggested as an option to re-establish lots megafauna.
Therefore try to return everything to proper ecosystem function

Question 67

problems with rewilding?

Answer 67

only can be reeastbalished with keystone species. A lot of these are extinct so they cannot be returned. Therefore using proxy species.

Therefore taking biota out of their now habitat and putting them in another.

Question 68

herbivore reintroduction

what are the effects on the vegetation?

A lot of these ecosystems have already been subject to other anthropogenic change

Answer 68

reintroduction of tool elf in LA-

biggest effect was on annual species (both on native and non-native)

grass species saw a positive change

had both diserable and undiserable effect.

Disturbunce hypothesis

Question 69

rewilding

many be onway to restablishing ecosystem fucntion

but have no way of knowing what happened before, cant say if the new introduction will benefit the ecosystem or not

Question 70

pollution:
impacts on ecosystem, pattern and complex.

Resources and the plant community

impacts of terrestiral nitrogen on ecosystems

Answer 70

the most diverse floras are assoicated with low nutreint soils

Western south africa:
-high alpha diversity- up to 130 species per 1000m2
-high beta diversity (turnover)- changing soils, frequent fire, long evoultionary history.

Due to leaching the soils are dedicent in: nitrogen, phosphorus, molybdenum, copper

Question 71

why do low nutrient soil supply more species?

Answer 71

park grass experiment in 1856
had 89 different plots varying in nutrient treatments.

plant species richness, biomass and pH are related; community composition responds to climatic perturbation and nutrient additions; soil is acidified and corrected by liming.

the study also showed a putative case of the evolution of reproductive isolation by reinforcement
expierment showed vegetation responds to increased fertility.

higher nitrogen levels= more plant diversity but less species richness.
cow slips, oat grass.

Question 72

Why does this happen?

Answer 72

low fertility- many species can co-exist as because superior predators are unable to dominate.
Therefore co-existence.

under higher nutrient conditions these stronger competitors dominate and eliminate inferior species.

Question 73

how do plants outcompete?

Answer 73

plant size increases so space decreases
plant height increases so light decreases

Question 74

Therefore resource avalibility alters the plant community situation.

Question 75

Nitrogen is all around us

Answer 75

All organisms face the issue of obtaining nitrogen.
80% of air we breathe is N2 its in an unreactive form therefore unobtainable.

obtainable organic compounds: reactive nitrogen species: urea, ammonia etc.

Question 76

3 natural processes by which unreactive nitrogen and be incorporated into ecosystems.

Answer 76

1. Biological n-fixation: bacteria living free from or associated with plants (ES costana)
2. mineralisation: occurs via weathering, decomposition
3. atmospheric depositon

Question 77

a history of nitrogen

Answer 77

the amount of nitrogen deposition has doubled since industrilaisation.
From the atmposhere to the biosphere.

where?
some is from industrial sources, whilst the rest agriculture: nitrogen fertilizers, cultivation of nitrogen fixing crops.
20o million t yr= only part of this is defitrified.

Question 78

synthetic nitrogen

Answer 78

the haber-process allows us to convert atmospheric N to ammonia.

therefore can create synthethic fertilisers therefore excess run off into ecosystems/ aquatic systems

post industrial- excess of man-made nitrogen sources

Question 78

impacts of additional nitrogen sources

Answer 78

cultural eutrophication- man made nutrient imputs into aquatic systems denote a change between plants/ animals and often algae

broad-scale eutrophication
norfolk broads- fertilliser runoff and sewage.
peak of phosphorous constrations in the river in the 1970’s.

signficant increases in algae plants and a decrease in plants.

phase 1- low nutrient= macrophytes dominate.
phase2- increased nutrients, still macrophytes with epiphytes
phase3- high nutrients shows high epiphytes and phytoplankton but macrophytes fazed out.

Question 79

effects on ecosystem

Answer 79

reduced macrophytes
abundance removed refugia for the zooplankton that fish eat

fish populations increase which control the phytoplankton.
this leads to a fish population crash after a while

phytoplankton thrives

Question 80

global eutrophication

Answer 80

*fertilliser/ sewage runoffs causing increased nutirent loading in esturays around the coast lines.
*not just an aquatic phenomina

Question 81

nitrate time bomb

ground water sources seeing acculimation of nitrogen

Answer 81

ascot et al 2017

vadose zone (interphase between soil surface and groundwater)

greater in north america, europe, asia.

Question 82

5 main impacts of of atmopheric nitrogen
2010

Answer 82

1. gas toxicity
2. toxic effect of nh2
   3.acidification
   4.impact on plant growth/competiton
   5.disruption of interactions (herbivory, mycorrhizae)

Question 83

troop and lerdau
(2004)

Answer 83

plant quality many change:

could be benefical for herbivore, increase in aa content, reduction of carbon secondary defence in the plant.

could be increase in nitrogen based secondary defences chemical

Question 84

community-level effects

Answer 84

any effects that the change of host plant quality have on the abudnace of herbivores could in turn have a selective impact on other plant communties. (selective impacts)

strauss in 1987
showed a change from beetles to aphids.

increased herbivory results in faster nutrient cycling.

Question 85

changes to the plant communtiy :

so what happens to the plant when we add more Nitrogen?

Answer 85

does species diversity change?
we know this from the field experiment.

Question 86

bbbink et al

Answer 86

different responses across different biomes

alpine: reduced shrub/bryophyte cover

boreal forest:
reduced shrub, increased graminoid.

mediterrranean forest:
dramatic change in lichens understory invasion by exotics.

tropical savannah: increase in sedges, loss of grasses and exotic grass invasion.

Question 87

summary of eggects

Answer 87

species diversity and species richness can vary depending on the ecosystem involved.

long history of n-deposition shifts many have already happened/ before ecologists started taking note.

but areas that havent seen much n-depo before such as alphine vegetation shows these predicted losses

Question 88

n-deposition in the UK

UKREATE- 14 experiments, habitats of high conservation value.

Answer 88

Clear responses were seen across the sites with the greatest sensitivity shown in cover and species richness of bryophytes and lichens.

Productivity was also increased at sites where N was the limiting nutrient, while flowering also showed high sensitivity, with increases and declines seen in dominant shrub and forb species, respectively.

impacts can ‘build up’ within an ecosystem such that even relatively low N deposition rates can result in ecological responses if continued for long enough.

Question 89

UK effects

Answer 89

vascular plant species
limited changes at realistic n deposition

bryophytes and lichens
negative sensitivity.
To experimental lichen addition.

due to a combination of firect toxicological effects but also due to an increase in vascular plant species growth.

Question 90

bryophytes and licnes

Answer 90

tendancy to focus on vascual rplants but these hold many important processes.

important role:
* water retentio (mosses, lock away flood water)
*locking away elivated nitrogen depositons (excess carbons, in peat that they form)
*therefore carbon sequestration