1. SCIENCE 1.12 Investigate the biological impact of an event on a New Zealand ecosystem. Internal – 4 credits

2. What are we thinking about? There are numerous events which affect New Zealand’s ecosystem, from short storms to long-term climate fluctuations, from slow erosion to sudden landslides, from creeping evolution to the sudden introduction of foreign species. You will study one event and the biological impact that event has had on an ecosystem. Our ecosystem is the Kaimanawa ranges ecosystem Our event is the a human action – the introduction of the Kaimanawa wild horses You will look at the changes in environmental factors due to the introduction of the horses. And how these environmental changes effect organisms within the ecosystem and the ecosystem as a whole.

3. But before we start….. We need to talk about some of the terminology that we will be using and that you need to think about when you write up your report. Some of the terms: 1.Ecosystem 2.Habitat 3.Environmental factors, abiotic and biotic 4.Ecological nice 5.Organism 6.Population 7.Biological community

4. Ecosystem Definition: All the organisms living in an area and all the environmental factors that affect them. This means that an ecosystem can be a tiny piece of decaying fruit or as large as the Southern Ocean. What are some examples of Ecosystems that you can think of?

5. Some examples of ecosystems A mountain

6. Alpine tussock grassland Lammermoor range, Otago

7. Alpine tussock grassland ecosystem Alpine rock and snow Large rivers Tussock grasslands Rock outcrops

8. Kaimanawa ranges sub-alpine ecosystem

9. Ocean ecosystem

10. Pasture ecosystem

11. Mangrove ecosystem The removal of mangroves growing on a tidal mudflat may increase the effect of waves, leading to greater erosion of the coastline, which may lead to the death of more mangroves.

12. Some others Sand dunes Native forest grasslands Tidal areas such as mangroves, mud flats, rocky shores

13. Communities in ecosystems Mountain ecosystem Alpine rock and snow Alpine tussock Steep mountain streams Isolated forests Native and introduced grasses What sort of communities do you think you could find in the Kaimanawa Ecosystem?

14. Communities Ecosystems are made of the habitat (non-living) and communities within it (living organisms). Defined as all the organisms living in an area and the relationship between them. All the plants and animals living in an area, being part of a complex food web are all heavily reliant on each other. Relationships can be so strong that the presence or absence of one key species can change a whole community. Think of the Kaimanawa Ecosystem, how has the addition of the horses into the community impacted other organisms in the community? Has it become part of the food web? What could result from it’s integration?

15. Population Group of individuals of the same species living together in the same area at the same time. They can be large or small. Eg, takahe in the Murchison Mountains Rainbow trout in Lake Taupo Kiwi in Rotoiti National Park Kaimanawa horses in Kaimanawa ranges

16. Species A group of organisms that can interbreed to produce fertile offspring. Members of the same species belong to the same gene pool and are reproductively isolated from other species. This means that they can’t breed successfully with other species.

17. Habitat The habitat is the place where an organism lives. Usually includes all the physical features of the environment, eg, the habitat of the black mussel is the mid-tidal zone of the rocky shore What is the habitat of the kaimanawa horses?

18. Adaptations Inherited characteristics that enable organisms to survive or to reproduce effectively. Every adaptation has a purpose. Structural – eg wings on a tui are for flight Physiological – digestive enzymes enable food to be broken down quickly Behavioural – migration of oyster catches between the North and South Islands allows food stocks to regenerate in both places

19. Ecological Niche The role or way of life of an organism in its biological community. The niche is a combination of where the organism lives, its habitat, and how it lives there, its adaptations. Name the organism Describe its way of life – feeding habits and patterns of activity (nocturnal? Diurnal? Migratory?) Describe its adaptations to its feeding habitat and activity patterns Describe other adaptations to its particular habitat and way of life. Each species has a unique niche and two species can not occupy the same niche - competition

20. Environment Surroundings of an organism and includes all the factors that act on an organism. They can be living or non living.

21. Environmental factors The event (introduction of horses) will have caused a change in environmental factors. You will need to identify what environmental factors have changed and are causing the change in organisms. Ecosystems are often controlled by one factor in particular, such as the length of time spent in sea water on a rocky shore. But there are also many other interactions happening in an ecosystem. What do you think could be some of the environmental changes that may have occurred as a result of introduced horses?

22. Abiotic and biotic Biotic factors – living factors, including interactions between organisms, such as supply of food, competitions, predation, parasitism and disease. Abiotic factors – non-living, physical factors such as moisture levels, wind speed, wave action, temperature, oxygen levels and light intensity. After watching the videos, make a list of some of the biotic factors you can think of that could be part of the environmental factors in the Kaimanawa area Make a list of the abiotic factors that could be associated.

23. Interrelationships The interrelationships between species and between individuals are a key aspect of biological communities. The relationships may be important biotic factors in the environment. The availability of food and the actions of herbivores and predators are important in determining the presence and abundance of organisms in the community. Predation is an important factor in controlling the size and density of populations of prey species, typically herbivores.

24. Feeding relationships Where an organisms fits in the food web of the community is important. Any change to the density or distribution of one organism in the food web can impact other organisms that rely on it for food. Competition for food can lead to a reduction in survival rate of an organism or cause the organism to move elsewhere for food. Horses are herbivores. There are no carnivores in New Zealand that naturally predate on them to control their numbers.

25. Competition Competition occurs when resources are in short supply. Competition is important in determining the presence, size, and density of population in a community. Intraspecific – between members of the same species Interspecific – between members of different species. This is harmful to both species involved. Plants compete for light, space, water, nutrients. Weeds can be a problem competing with native plants. Animals mostly compete for space, food, water, shelter, nesting sites.

26. A biological impact A biological impact could be a change in the number (density) or range (diversity) of organisms. This change could have an impact on the ecosystem as a whole, effecting food chains and food webs, etc. When you consider a impact, you don’t make a judgement whether it is good or bad, you just consider data, evidence and known facts. What are some biological impacts that could be occurring as a result of the introduction of the horses?

27. Combined effects Within an ecosystem if one factor is changed, it can have an effect on other factors. Can you think of any examples?

28. Human effects on ecosystems Humans can have a direct or indirect effect on an ecosystem. For example, humans can spill oil which may cover a shoreline with thick, black crude oil. The fact that humans did it, makes it a biotic effect, but the effect on the shore will be due to abiotic factors such as reduced oxygen levels, lower light levels or an increase in the levels of toxic chemicals.

29. Indicator species Organisms have preferences and limits for environmental factors and where they want to live. An indicator species is one whose numbers are sensitive to environmental threat, and which can be used to indicate the state of health of that environment. When we know what effects a species, we can use their number, health and distribution to identify issues in an ecosystem. Do you know any of these?

30. Plant indicators Because plants can’t move, they are good indicators. They are affected by the nutrients and water that their roots can obtain. Plants will then show the effects of ground disturbance, like that caused by being trod on all the time. (especially from above) Trampling by horses? Could this be an issue and how? See if you can find some plant species that are being trampled by the horses which could have an impact on the ecosystem as a whole (impact on the food web)

31. Insect indicators Insects are widespread and involved in nearly every community relationship including decomposition of forest litter, pollination, parasitism and predation. Also important food sources for birds, lizards, tuatara and freshwater fish. Insect larvae are often found in streams, their abundance indicates a lack of pollutants and good oxygen levels. How might this relate to the Kaimanawa Ecosystem?

32. Some examples of indicator species Woodrose – a parasitic flowering plant Forest health in parts of the North Island If there is lack of woodrose, it indicates presence of browsers, native pollinators, seed dispersers and host trees. Kiwi lack of kiwi indicates an abundance of mammalian predators

33. Most destructive species in NZ What do you think is the most destructive species in NZ?

34. Probably humans! Why? We have altered nearly every Ecosystem in New Zealand. We have introduced over 32 mammals, 33 birds, 3 amphibians, 18 fish, 33 reptiles, thousands of species of invertebrates, plants and micro-organisms into New Zealand who have all had an affect on Ecosystems, eg, rat, possum, goat and wild horses.

35. Introduced species Of all of the species introduced, many didn’t survive, thankfully! Eg, Zebra, camel, squirrels. Of those that survived, many became major pests within a few years. To exterminate little ones such as rabbits and hares their natural predators were introduced – weasels, ferrets and stoats. Larger pests such as deer and pigs were shot as their natural predators (wolves, tigers, lions) were too dangerous! Really? Didn’t work well – what do you think was the consequence? One of the worst is the possum along with many plants

36. 1. Environmental Factors Describe how the event changed environmental factors in the ecosystem you are investigating. You need to find information on at least two factors. Eg, In the stream that ran through native bush, average water temp was 15C during the sampling period. In the stream in the industrial area, average water temp was 17C Organisms need to be adapted to environmental factors to survive, so if they change, an organism may be affected. see hand out. What sort of environmental factors do you think the horse could impact?

37. 2. Changes to environment Explain how the introduced horses changed the environment: Eg, the suspended particles in the water in the stream in the industrialised area contributed to heating the water as the particles warmed up. There is less dissolved oxygen in warm water than in cold. The warmth of the water in the stream in the industrialised area meant there could be little dissolved oxygen in that part of the stream. You can consider changes to light intensity, pH, amount of moisture, stream clarity, temperature, oxygen levels, shelter, food availability, competition, composition of substrate (soil) etc.

38. 3. Impact – effect on population of organisms. Explain how these changes have had an impact on the organisms in the ecosystem (2) You can discuss diversity and density of species (plants or animals) that have been effected here. – eg, changes in population numbers, distribution of organisms, density of populations, size of organisms in a population, age structure of population, key species, feeding relationships, interrelationships (eg, mutualism, parasitism)

39. 4. Implications for ecosystem The implications that the changes have for the ecosystem as a whole can be discussed here. Consider changes in biodiversity, food chains/webs, energy flow, nutrient cycles, density and distribution patterns, presence or absence of key species, substrate. You need to link your findings and biological ideas into a comprehensive discussion of the biological impact of the event on the ecosystem. Make causal links – constantly explaining how or why one change caused another change. Also discuss the implications of these changes for the organisms and the ecosystem.

40. Ecosystem – impact of removal of some species Habitat destruction Few organisms in food web Links may be removed Decreased stability of web Likely loss of biodiversity as plants die out and animals die or migrate Remember to compare the ecosystem with and without the horses and use data, photos – evidence to support it.