1. Applied Terrestrial Ecology (WAP 416)
Lecture notes by Mrs M M Ngwenya or
(Office no. NSB 33)

2. Course Objectives
Build-up applied knowledge relating to the earth and its inhabitants, the relationships between organisms and their environments focusing on the ecosystem concept, structure and functioning of ecological systems, processes and factors .
Determining the structure and functioning of large mammal communities and interactions between them.
Acquire an understanding of ecological principles as they apply to large mammals.
Examines responses of systems to changing environmental conditions and applies knowledge to conservation and management issues.
Course goal: to expose students to basic concepts that are important in large mammal ecology.
The specific objectives are:
To enhance the students' appreciation of principles, concepts and processes in large mammal ecology.
To explain general concepts and principles that form the foundation of ecology.
To develop interdisciplinary knowledge that links an understanding of ecology and applying ecological knowledge to sustainable use of natural resources.
To develop an appreciation of the paradigm shifts in wildlife management and the determinants of large mammal structure.
To provide examples and explain how general ecological concepts apply to field assessment and experimentation in natural resources management. 

3. Course Outline Course introduction and important definitions
Wildlife management and adaptive management
Body size and large mammal ecology
Population ecology and regulation
Foraging theory, Optimal foraging theory
Community interactions
Ecosystem modeling- different types of models
Determinants of community structure- rainfall and soil nutrient status; herbivory
Biomass and production in relation to rainfall and primary production
Impact on vegetation
Effects on other herbivores
Concept of carrying capacity
Methods of determining carrying capacity
Applications and problems
Overpopulation and management of locally abundant animals
Case studies
Wildlife censusing methods
Planning for wildlife management- process, use and hierarchy of planning

4. Large mammals What are large mammals? Why large mammal ecology?
What characteristics are affected by body size?
Large mammals mgt issues?

5. Definitions
Wildlife – all forms of life of aquatic and terrestrial flora and fauna indigenous to an area and found in their naturally associated environments and they range from micro-organisms to large species.
 Wildlife management – the sum total of all actions taken in the conservation of all wildlife resources. Wildlife management actions taken depend on the scope of management and objectives of the ecologist/resource manager.
Wildlife management is a part of wildlife conservation.
Conservation- the protection maintenance, rehabilitation, restoration and enhancement of wildlife and includes the management of the use of wildlife to ensure sustainability of such use.

6. Wildlife Conservation
Involves all professional and lay activities to achieve wise use of resources.
What is wise use of resources?
Aldo Leopold, “man living in harmony with the land.” What is harmony?
Wise use and harmony are subjective and they do not describe the activities constituting the terms.
Conservation: scientific and socio-economic sectors.
Professional activities:
Education: legislation, extension, training of professionals, public policy
Administration: public opinions, communicate locally, regionally & internationally, set goals and budgets.
Wildlife Management: habitat manipulation, population management
Wildlife research: environmental & animal properties and interactions
Law enforcement: monitor illegal activities, prevent violation of laws

7. Wildlife Management It is a part of wildlife conservation.
Wildlife management actions taken depend on the scope of management and objectives of the ecologist/resource manager.
Depends on ecological principles used to understand the processes that lead to change e.g restoration of degraded ecosystems imply that ecologists understand the linkages between processes of degradation, land use and restoration of degraded ecosystems.
Assumed understanding of the building blocks (key ideas linked through ecological processes that management can use to alter direction of change).

8. Understanding Building Blocks
Managers in a protected area are concerned about the increased impact of off-road activities. This problem can have several hypotheses e.g.
H1. Acts negatively & affects the breeding of large cats/
H2. Contributes to the degradation of vegetation through compaction of soils and vegetation.
The 2 hypotheses have different building blocks. Identify other hypotheses and the building blocks you could use to test hypothesis.

9. Adaptive Management vs Wildlife Management
Wildlife mgt assumes understanding of ecosystems and employs principles to enhance them, adaptive mgt is a new approach to resource mgt.
Its management that establishes measurable objectives, both in ecosystem function and social desires, increases current levels of data gathering by managing scientifically, monitoring and adjusting management practices to meet changes in ecosystem capacity or social demands. Its key characteristics are:
Uses a trial and error approach.
Recognizes that predictive models in ecology are difficult.
Accepts that resource mgt is a difficult field as variation is embedded within ecosystems.
Accommodates the unpredictable interactions between people and ecosystems as they evolve together.
States that rules and mgt criteria must be flexible enough to changing biophysical events and changing human goals.
Integrates feedback loops into wildlife mgt and allows for incremental changes instead of major readjustments in practices after a long time.
Regards wildlife mgt policies as “experiments” to learn from and emphasizes the importance of feedbacks from the environment in shaping policy.

10. Community Interactions
Complicated ecological interactions at various levels are the basis for management.
Interactions are the driving force in natural selection and occur between:
Animal- animal
Plant- plant
Animal – plant
Climate – plant
Climate – animal
Give examples of interactions. 
Interactions may be beneficial, detrimental or maybe neutral in some instances.
Intra-specific interactions may cause physiological and behavioral changes (stress, social pressure, aggression, submission), which act as spacing mechanisms, whilst inter-specific interactions give rise to the niche theory (recall fundamental and realized niche).

11. Climatic Effects
Exemplified by the Serengeti large herbivore populations, which have adapted to the rainfall patterns through seasonal migrations.
During the wet season (nov to may), the herbivores feed on the more arid short-grass plains. Wildebeest and zebra give birth during this period when the protein content of grass is high for the milk-producing females.
When the short grasses on the ridge tops dry out, zebra and buffalo move down the catena, followed by wildebeest and other species. In this grazing succession, the larger animals remove the coarse material leaving the lower grasses, which are more favorable for the smaller animals.
Larger species are unselective and meet energy needs on low quality diets whilst smaller herbivores can sustain themselves on higher quality food remnants.
Herbivore coexistence is achieved through differences in sizes and the need for different amounts and qualities of food.
Above is called forage facilitation with each herbivore migration facilitating the grazing of other species: elephant, buffalo, zebra, wildebeest etc. changes in habitat productivity have resulted in herbivores learning to track these changes in primary productivity with accuracy. 

12. Herbivores and Herbivory
Herbivores face changes in habitat productivity and have learnt to track changes in primary productivity with accuracy.
Large herbivores are divided into those that feed on grass and herbs and those that feed on woody vegetation.
Herbivores have significant impact on grassland composition and tree structure.
Herbivores increase the nitrogen content of soil through urination and defecation i.e. they facilitate nutrient cycling. 

13. Large Mammal Ecology Play an important role in ecosystems.
Control ecosystem processes and are in turn controlled by them.
Mega-herbivore populations interact with the environment and other species of plants and animals and important interaction include:
The predatory and disturbing impacts of herbivores on vegetation.
Competitive and mutualistic interactions among herbivore species.
The consequences of changes in species representation for ecosystem structure and function. 

14. Feeding Habits
African ungulates (hoofed) are separated ecologically by the proportion of woody browse and grass in the diet.
Herbivores can be pure browsers e.g. giraffe; mixed feeders e.g. elephants, impala and pure grazers such as white rhino, wildebeest and zebras.
There is a gradation from grazers to browsers depending on environmental conditions. Although diet separation occurs, there is a high degree of overlap.
Sub partitioning of food resources based on plant species, growth stage, height and tissues eaten e.g. young animals, pregnant or lactating females have high nutritional requirements.
Classification of the herbivores into feeding habits depends on mouth morphology, stomach structure and digestive physiology i.e. adaptation to breakdown and digest fibrous material.

15. Table 1: Ecological groups of African Ungulates
Feeding type and mean adult weight
grazers
Mixed feeders
browsers
Large
> 1000kg
White rhino
Medium kg
Buffalo
Small
<100kg
Nyala
Put the following animals into the groups given in the table:
Hippotamus, impala, zebra, giraffe, bushbuck, tsessebe, warthog, eland, black rhino, waterbuck, wildebeeste, reedbuck, roan, elephant, kudu, sable .

16. Animal distribution
It is dependent on the dominant vegetation categories such that the different ecological regions are associated with specific herbivores resulting in different percentages of herbivore biomasses in each herbivore group as shown in the table 2.
NB. Elephant and buffalo used in table 2 are from the National Park from which the data on ungulate densities was taken. The estimated percentage of these two species, therefore are based on data from other areas of the National Parks Estate for which best estimates are available.

17. Table 2: Percentage of total herbivore metabolic biomass in each herbivore group, according to the dominant vegetation type
Vegetation category
Body size
Grazers
Mixed
Browser
Total
Miombo woodland
(principally regions 2 & 3)
Large
Medium
Small 15 18 5 3 44 1 4 63 28 9
Mixed wood land
(principally region 4) 10 36 7 6 48 39 13
Mopane savanna
(principally region 5) 33 21 45 27

18. Feeding Preferences
The ecological classification into grazers, browsers and mixed feeders is a poor descriptive terminology and more appropriate classification would be:
Bulk and roughage eaters (BRE) – characterized by capacious stomach filled to capacity with relatively low quality food composed mostly of grass.
Concentrate selectors – characterized by small stomachs filled only to 50-60% of their capacity with concentrated food composed mostly of the leaves, flowers and fruits of forbs, shrubs and trees.
Intermediate feeders - characterized by an ability to adapt in different seasons and areas towards one or the other of the above 2 feeding types.
NB. Body size has an important influence on the ecology of herbivores as it affects the bodily or metabolic energy, nutrient requirements and energy requirements of an organism.

19. Metabolic Rate (MR)
MR – amount of energy required by an organism per unit time.
Basal MR – minimum amount of energy an organism needs to respire to maintain life when the body is at rest/ minimal amount of energy expenditure needed by an animal to maintain vital processes.
Daily energy expenditure – energy requirement for locomotion, thermoregulation, growth and reproduction over 24hours. It is usually about 1.5 to 3 times the BMR.
The most important factor affecting MR is size. Generally large animals need more energy each day to live but MR is not directly proportional to body mass.

20. Calculating MR
The slope for BMR is actually shallower than the steeper directional relationship one i.e an animal 10X heavier does not need 10X as much food/day. This relationship is expressed by the allometric equation:
BMR = a (body mass)b
Where b is the slope of the line and tends to be close to 0.75 and because b is less than 1, larger animals need less energy per day relative to their body mass than smaller animals.
BMR = 70 * W075 kcal
Absolute Met. Rate = 70 * W075 * 1.5 kcal/day = Daily Energy Expenditure
While there are sex differences and individuals vary, the equation gives the
average/mean standard basal metabolism of a variety of mammals.
The specific MR or daily energy expenditure per unit live mass:
SMR = 70 * W075 * 1.5 kcal/kg /day W

21. Limits Imposed on Body Size
As body weight increases, the weight specific metabolic rate decreases. Therefore small animals have a higher metabolic rate per unit of body weight than large ones. Weight specific rates of small endotherms rise so rapidly that below a certain size, they could not meet energy demands. The world’s smallest mammal, shrew-mouse of Africa Suncus etruscus weighs on average about 2gm.
Caused by the ratio of surface area to body mass or volume such that an animal loses heat to the env. in proportion to the S.A exposed. Given the same environmental conditions, a large animal loses proportionately less heat to the environment than a small one – large animals have smaller SA/V ratio than smaller ones and lose less heat to the environment.
To maintain a constant internal ToC , small animals have to burn energy rapidly.

22. Application to herbivores
Small ungulates face a higher relative energy and nutrient need than large ungulates- need a relatively high intake or should ingest high quality food. However, the low absolute requirements of small animals enable them to feed selectively on high quality food.
This relationship became known as the Jarman-Bell principle which generally states that smaller organisms require higher quality diets because of higher metabolic rates per unit of body tissue.
Larger animals have lower relative energy requirements, eat bulky low nutrient foods increased gastro-intestinal tract (GIT), allows them to use forage of lower quality (longer ingesta passage rates).
Elephant are mixed feeders but browse is less abundant than grass, but is more nutritious. An elephant takes more time to get 10kg of browse than 10kg of grass. Easily fills stomach with grass.  

23. Feeding Behaviour
Behavior is action that alters the relationship between an organism and its environment.
Behavior may occur as a result of
an external stimulus (e.g., sight of a predator)
internal stimulus (e.g., hunger)
or, more often, a mixture of the two (e.g., mating behavior )
Foraging for food is a crucial behavior for animals. Like all behavior, it requires the interaction of many components.

24. Foraging Behaviour
Foraging behavior refers to all “ food related activities” including looking for, processing and traveling between food sources or patches.
Herbivores employ various strategies to meet their energy requirements – foraging strategy i.e. manner in which animals seek food and allocate time and effort in obtaining it.
Food resources are distributed in patches across the landscape in an uneven manner and patches vary in size and the quality and quantity of resource so the predator needs to locate profitable items.

25. Foraging Theory
Energetically unprofitable to spend time where forage densities are low such that animals want to maximize energy gain:
Net energy gain = energy from food intake – energy expended
The optimal foraging theory (OFT), leads to a better understanding of foraging behavior. Although it was different in detail, it demonstrated the need for a model where food item selection of animals could be understood as an evolutionary construct, which maximizes the net energy, gained per unit feeding time.
Robert MacArthur and Eric Pianka in 1966 first proposed an optimal foraging theory, arguing that because of the key importance of successful foraging to an individual's survival, it should be possible to predict foraging behaviour by using decision theory to determine the behaviour that would be shown by an "optimal forager" - one with perfect knowledge of what to do to maximise usable food intake

26. Optimal Foraging Theory
Attempts to explain predator behavior since no predator eats everything available- due to habitat and size constraints, but even within habitats, predators eat only a proportion of what is available.
E is the amount of energy (calories) from a prey item. h is the handling time which includes capture, killing, eating and digesting. h starts once the prey has been spotted. E/h is therefore the profitability of the prey item.
Animals typically eat the most profitable prey types more than would be expected by chance (will appear in the diet more often than it is encountered in the environment).
Predators do not, however, eat only the most profitable prey types.
Other prey types may be easier to find, and E is not the only nutritional requirement. Toxins may be present in many prey types, & variability of diet prevent a toxin from reaching dangerous levels.

27. OFT cont’d
The predator attempts to maximize E/(h+s), where s is the search time involved. For a range of prey, the predators average intake rate is Eaverage/(haverage+saverage). Where Eaverage is the average E of all prey items in the diet, haverage is the average handling time and saverage is the average search time.
A predator that finds a new food item has two choices. It can eat the new item, and profitability is Enew/hnew or it can leave it and search for an item already in its diet, where profitability is Eaverage/(haverage+saverage). The predator should eat this new item when Enew/hnew ≥ Eaverage/(haverage+saverage) because the new item increases Eaverage/(haverage+saverage).
Note: - Predators with short haverage and long saverage should be generalists and include a wide range of items.

28. Cont’d
Specialists have a longer haverage and saverage , they are choosy. Lions, e.g. have a very low saverage but a high haverage , which can be prohibitively large for some prey individuals- pick out the sick and old.
Predators should be generalists in unproductive environments and specialists in productive environments.
Predator- prey co-evolution makes it non-profitable for a prey item to be included in the diet, since many anti-predator defenses increase handling time e.g. porcupine quills, crypsis and other predator avoidance behaviors.

29. Cont’d
When predator density increases, the search time for food items depends on the density of the prey.
Handling time, is species specific. At low prey densities the predator is searching most of the time and eating every prey item it finds & at high prey densities, each new prey item is caught almost immediately. The predator spends almost all of its time catching, eating or digesting the prey. It chooses only those individuals with the highest E/h.
Departures from optimality often help to identify constraints either in the animal's behavioral or cognitive repertoire, or in the environment, that had not previously been suspected.
Identification of constraints identified results in foraging behavior often approaching the optimal pattern (even if it is not identical to it).
Herbivores often encounter forage that is largely indigestible, of low nutritional value and patchily distributed- Great variability in food composition.

30. OFT Application
There are many versions of optimal foraging theory that are relevant to different foraging situation. These include:
The optimal diet model, which describes the behavior of a forager that encounters different types of prey and must choose which to attack
Patch selection theory (spatial choice), which describes the behavior of a forager whose prey is concentrated in small areas with a significant travel time between them
Central place foraging theory, which describes the behavior of a forager that must return to a particular place in order to consume its food, or perhaps to hoard it or feed it to a mate or offspring.

31. Optimal Diet Selection
The 4 optimal economic decisions pertaining to the optimal diet model are that a herbivore should:
Prefer the most profitable forage i.e. one that yields the greatest net energy gain.
Feed more selectively when food items are abundant
Include less profitable items in the diet when the most profitable foods are scarce.
Ignore unprofitable items, however abundant when profitable forage/ food items are abundant.

32. Cont’d
The optimal diet rules may not apply under natural conditions because of food preferences and animals may not always choose larger, more profitable animals over small ones.
Food preference is the extent to which a food is consumed relative to its availability, and some foods are more preferred than others.
Preferred food items are different from principal foods – items eaten in greatest quantities by an animal population as Principal not exactly the preferred food.

33. Spatial Choice
Positions animal in a landscape prior to selecting plant spp or parts from an aggregate of available plants.
Landscape characterized by physiognomic and thermic features of a mgt unit which influences animal mvt patterns.
Unit is characterised by boundaries and distribution of plant communities, degree of accessibility and distribution of water, thermal and mineral areas.
Animals through experience understand the nature of landscape and seasonality of desirable spp.
The more experienced the animal is the greater its ability to optimize grazing tactics.
Animals are limited by water availability and landscape terrain.
Foraging preferred sites have high utilization:herbage mass ratio and grazing avoided areas contain low value food or are inaccessible to animals.

34. Optimal Patch Selection
The 4 optimal economic decisions pertaining to the patch selection model/foraging efficiency are that a herbivore in a heterogeneous environment should:
Concentrate foraging activity in the most productive patches.
Stay in those patches until their profitability falls to a level equal to the average for the foraging area as a whole.
Leave the patch once it has been reduced to a level of average productivity.
Ignore patches of low productivity

35. Utilization Time
How long should a herbivore remain in a habitat patch seeking food?
Graph provides theoretical answer:
 The curve represents the cumulative amount of food harvested relative to the time in the patch. Straight line (tangent) represents average food intake per unit time for the habitat as a whole. Beyond this net food gain declines below average- herbivore’s optimal time to seek a more profitable patch. Model predicts that as travel time between patches increases, herbivore remains in patch longer to balance energy lost in travel.
Length of stay related to richness of food patch, time required to get there and t to extract resource. Initially high rate of extraction and energy gain but as t progresses, the abundance of resource declines until its not profitable for herbivore.
Too long a stay depletes resource and leaving too soon, resource not utilized efficiently.

36. Body Size and Popn Regulation
Major differences exist between the processes of population regulation in small mammals (under 30kg) and those in larger mammals.
Regulation attributed to 2 types of factors:
Density-dependent regulation – cc, limited resources, increased competition etc
Density-independent influences – climatic conditions, moisture, Temp etc

37. Regulating Factors
Two paradigms that interact to affect populations. These influences reflect on the population’s resilience or rate at which it returns to equilibrium after a disturbance.
Resilience is strongly influenced by reproductive rate, which is affected by body size:
Small bodied animals have shorter lives/die early, good colonizers, generalists, don’t reach cc, large number of offspring, minimal parental care, reproduce faster and recover from losses quickly – high resilience. These are r-selected animals i.e. r from rate of increase in logistic curve.
Large bodied animals possess more stability about equilibrium level, reproduce slowly and require a long time to return to equilibrium, attain and remain more/less at cc, competitive, poor colonizers, specialists, and fewer offspring. These are K-selected species and K from cc.

38. Cont’d
Small mammals are regulated by intrinsic mechanisms (higher post natal losses, reduced litter size, age at first parturition) before food becomes limiting.
In contrast, large mammals are regulated by extrinsic factors such as direct effects of food limitations on survival and reproduction.

39. Large Mammal Popn Growth
It has been predicted that megaherbivores in favorable habitats exhibit an eruptive oscillation pattern subdivided into 4 stages:
Initial phase of rapid expansion with high fecundity and low mortality with vegetation condition deteriorating towards the end of the period.
Temporary stabilization as population reaches then exceeds cc of the habitat, vegetation degradation accelerated and animal condition declines.
Phase of rapid decline in numbers as population adjusts to lowered cc brought about by impacts on food resources.
Final phase of stabilization in the degraded habitat at a density lower than that reached during earlier stages.
Use a graph to illustrate these stages. 

40. Cyclic Plant-Herbivore Relationship
As herbivore population increases, vegetation biomass decreases and as herbivores decline, vegetation increases. Eventually vegetation growth and herbivore consumption reach a steady state/eqm with the woody browse.
Oscillations caused by plant-herbivore interactions. Exhibit time lag between vegetation recovery and growth & decline of herbivore, herbivore feeding on future vegetation growth.
Plants are able to recover because they have an ungrazable reserve biomass, but if grazed to a point where the reserve is too sparse to maintain production, they become extinct.
Herbivore declines allow vegetation to recover and herbivore increases again and the 2 populations approach/reach eqm, the vegetation with grazing pressure and the herbivore with its food supply.

41. Deviations from Predictions
Large mammals rarely do this. Typically, populations overshoot this equilibrium and equilibrate in a series of dampened oscillations unless further perturbations occur.
In some circumstances, oscillations form a stable limit cycle. Occasionally, populations crash after greatly exceeding carrying capacity e.g. the elephant population in Tsavo National Park.
In Hwange National Park, the elephant population has increased to densities that exert a major impact on tree populations, which shows that no stable eqm is reached with vegn.

42. Hypotheses
Several hypotheses have been proposed to explain why elephant populations fail to stabilize before severe damage is done to the habitat:
Range compression – restricted habitat as a result of hunting, settlement and other human disturbances.
Population eruption following cessation of ivory hunting resulting in overshooting K.
Elimination of human predation.

43. Thus the response of a population is as much the outcome of historical events as it is of current management practices.
Note: This pattern of herbivore increase to densities to which they overexploit and depress their own food resources is unstable & seems incompatible with large, K-selected animals like elephants.

44. Other Regulating Factors
Dispersal and predation dampen population oscillations, lowers the peak biomass level attained and hence reduce the impact of herbivores on the vegetation.
The 2 alleviate vegetation over-utilization. Once, these patterns were considered qualitatively different but they have similar effects- remove animals/depress density below saturation level set by nutritional limits.

45. Species Survival
K-selected species are adapted to habitats close to their cc i.e. scarce resources and competition results in high mortalities in young age classes.
The short generation time of small mammals mean that fluctuations occur in the adult age groups as resource availability varies.
Differences are important for conservation as efforts are directed towards the larger animals that have low reproductive rates and poor dispersal rates- but vulnerability to extinction varies between species with the common ones less vulnerable than restricted ones.

46. Species Extinction
Extinction is a natural process and many species are disappearing today without being discovered – estimated at 100 species per day.
Extinctions result from deaths that exceed births; emigration that exceeds immigration and small populations where females of reproductive age have smaller chances of meeting a fertile male i.e. the size of the breeding population/effective population size is always smaller than the actual population.
Small populations are prone to inbreeding – mating among close relatives; and genetic drift – random fluctuation in allele frequency over time due to chance alone without any influence by natural selection.

47. Causes of Extinction
The impact of large herbivores on the habitat results in FRAGMENTATION- small isolated habitats, which result in inbreeding and genetic drift, and reduces resilience of populations.
With isolation, the population’s sex and age structure is important in ensuring that there is a minimum viable existing.
Extinctions begin with isolated local ones and when enval conditions deteriorate, the spp is unable to replace itself.
Small isolated popns persist as non-reproducing members before succumbing to starvation and predation.
Small popns are subject to inbreeding and genetic drift reducing its ability to withstand enval conditions.
Define the terms inbreeding and genetic drift.

48. Types of Extinction
Deterministic extinction – result of some force or change from which there is no escape e.g. the Cretaceous-Tertiary extinctions (period of massive changes long ago when earth was covered by shallow seas, marked by rise of angiosperms and extinction of dinosaurs; evolution of birds and appearance of primitive mammals); destruction of habitat local or regional scale
Stochastic extinction- result of normal random changes within the popn (demographic) or env. Normally don’t destroy a popn, but thin it out. Smaller popn faces an increased risk of extinction.

49. Stochastic Events
Demographic stochasticity- chance variations in individual births & deaths.
Enval stochasticity- adverse enval changes caused by deterioration in enval quality. If all members are affected equally, the popn maybe reduced to a level at which demographic stochasticity takes over.
Continuation of a popn at low levels depends upon the size of individuals, mode of reproduction, longevity and seed bank in plants.
The extinction vortex shows how a combination of factors feed on another and accelerate the spp toward extinction.

50. Extinction Vortex
Popn size Enval variation (habitat loss, reduced cc) Demographic variation (age structure, reduced birth rate) genetic impoverishment (inbreeding, juvenile deaths) Endangered popn

51. Survivorship Curves
Depicts age-specific mortality. Obtained by plotting the no. of individuals of a particular age group against time.
Survivorship and mortality information provides leads in determining the causes of death and ultimately the processes that affect the population dynamics of a given spp.
3 hypothesized survivorship curves have been recognized. Identify and illustrate them.

52. Modelling
Models are used to explain or predict the behavior of ecosystems & wildlife.
Major appeal is the predictive power e.g. rainfall & vegn biomass model used to predict animal biomass that can be supported in a given env.
Simplify rlns in complex biological systems involving interrelationships of different species.
A good model captures essential details and leaves out non-essential details.
A model is as good as the data & assumptions on which it is based. There are some uncertainties.

53. Terminology in Modelling
Common terms compare opposites.
Exogenous vs endogenous
Static vs dynamic
Eqm vs diseqm or non-eqm
Deterministic vs stochastic
Exogenous variables are determined or set outside the model (independent).
Endogenous- set in the model (dependent)
Value of endogenous variable changes when the exogenous variable changes e.g. animal biomass depends on rainfall amount.

54. Static vs Dynamic
A static model does not account for time. Identifies the before and after outcomes but does not trace the path that the model takes to move from one eqm position to another.
A dynamic model contains time as a variable that can be used to trace how the model moves from one eqm position to the next.

55. Eqm vs Diseqm Eqm models reach a stable position- convergent models.
Diseqm models have no tendency to reach stable position- divergent model.

56. Deterministic Model
Deterministic model- takes no account of random events and gives a reproducible result.
Assumes an outcome is certain.
Solved by numerical analysis or computer simulation
Described by sets of differential equations.
Appropriate where there are large numbers of individuals & its assumed that the importance of statistical variations in the average behaviour of the system is relatively unimportant.
Assumption may not be valid.

57. Stochastic Models Governed by laws of probability.
Describes a sequence of outcomes from a particular initial event and prob of each set of developments to occur through time.
The same process can produce a variety of results.
Appropriate where either the no. of individuals is small or there is reason to expect random events to have an important influence on the behaviour of the system.
More useful when taking individuals as discrete units rather than continuous variables.
Includes a random element & takes account of behavioural factors.

58. Deterministic vs Stochastic
Deterministic model is based on a fixed value based on literature.
Based on a randomly selected value from prob.
In most biological systems the no. of spp involved & the interactions btwn them mean that analytical soln for stochastic models will not be feasible.
Repeated/many runs of computer simulations for deterministic model with different realisations give a picture of the central tendency and dispersion of outliers.
Stochastic is more realistic than deterministic e.g. a person’s consumption is not only dependent on their income but influenced by factors such as age, time year, tastes, style etc- parameters difficult to measure (take time)

59. Population Modelling
Large no.of factors interact in determining the size of animal populations: rainfall affects food supply; inter& intra-specific competitions, diseases, accidents, predation etc.
Logistic growth model tries to predict outcomes of various interactions within the community i.e. predicts K using a deterministic model.
Enval factors vary and realistic ecological modelling should incorporate the prob of such events occurring thru stochastic models.
Dynamic savanna systems can’t be adequately managed using deterministic models as disturbances occur due to biotic, abiotic or a combination of the 2 factors.

60. Ecosystem Models
Required to understand and be able to predict the outcome of interactions of trees, fire, elephants, browsers, grazers &grasses.
Developed to aid understanding of research results & provide mgt guidance.
Models are tested against current and past observations.
Needed to address mgt issues such as the effects of anti-poaching patrols, controlled burning, tourist use, culling prog.
Ecosystem simulation models are required if we are to understand and be able to predict interactions over time.
Look at the design of the area, migratory patterns of animals, human impact on the system, rainfall received (wet & dry season), inside & outside park.

61. Impacts Of Herbivores on Community Structure
Megaherbivores interact with & other spp of plants & animals and eles, rhinos, hippos etc. modify vegn structure.
Herbivores have direct impacts on vegn- consume plant parts; damage vegn- remove leaves, bark, break branches, depress growth or cause plant mortality during tree-feeling and uprooting.
Control height range (vulnerable to fires), expose trees to wood-boring beetles, fungal infections and other pathogens, felling fatal if plant can’t coppice.
Removal of plant cover makes soil vulnerable- compaction & erosion, reduce resources for regrowth & cause overall decline in plant abundance.

62. Elephant- Loxodonta africana
Pluck grass, forbs & creepers, uprooting them, stripping leaves, fruits, twigs or bark form woody trees & shrubs.
Impacts depend on spp, level of damage, season, ele densities, period damage is sustained & interactive effects of other factors e.g. fire, rainfall, soil properties etc.
Change woody spp composition e.g. in Sengwa Research Area A. tortilis & G. flavescens declined due to felling, debarking & uprooting.
Change vegn structure (physiognomy) as old mature trees escape damage & spp regeneration suppressed e.g F.albida in Mana Pools.
Baobab Adansonia digitata is susceptible to ele damage (soft, pithy wood) & declines occurred widely but baobabs in Zambezi valley escaped due to inaccessibility of trees on the steep escarpment.
Mopane in Sengwa affected thru woody plant biomass reductions- coppice regeneration hleped.

63. Ele Impacts Cont’d
Miombo woodland (Brachystegia & Julbernadia) in Chizarira & Zambezi area killed due to felling, ringbarking & uprooting.
When ele densities exceed 0.5per sq.km, savanna woodlands are converted to shrublands. Bird spp diversity is correlated to foliage ht diversity & bushbuck which prefer thickets –vely affected.
Less preferred spp increase in abundance. Reduce impacts thru dispersal to other areas & culling???
Densities < 0.5 per sq.km have beneficial effects- open up canopies- encourage faster growing plants (gap colonizers) early seral spp; better forage quality (coppice regrowth) & repeated heavy browsing stresses plants (reduce deterrents) by interfering with plant anti-herbivory chemistry.
Disperse seeds for many plants.
Eventually eles will affect their habitat resulting in popn crushes. Some say popn eruptions are episodic/temporary with seasons.

64. Impacts of Hippopotamus Hippotamus amphibius
Convert areas of medium tall grass cover to a mosaic of tall & short grasses or lawnlike grasses.
Increase terrace erosion & bush encroachment due to redn in fire. Palatable grass spp Themeda triandra; Heteropogon contortus & Cenchrus ciliaris maybe replaced by unpalatable Sporobolus pyramidalis & other creeping spp.
Trampling compacts soil structure, impacts of raindrops on bare soils increase erosion & reduce water infiltration.
Greatest impact is on relative abundance of grass species.

65. Impacts of Giraffe Giraffa camelopardalis
Greatest impact is on favoured spp of A. tortilis, Z. mucronata sausage tree Kigelia africana & Strychnos madagascariensis.
maintain trees at browse hts not exceeding 3m.
The canopy shapes of trees were changed by heavy browsing & the time taken trees to grow (above 3m) beyond fire susceptible ht classes was changed from 8yrs to 21yrs for A tortilis & 4yrs to 19yrs for A xanthphloea.
Exposed to anthrax when it eats soil where B anthracis spores persist in soil, carcasses and bones. Infection is dose dependent.

66. Impacts of Black rhino Diceros bicornis
Hook lipped. Browse woody scrub under 1m in ht esp acacias and may consume over 50% of the above ground parts in this ht range. Also eats fruits.
In arid areas obtains water from succulents e.g. Euphorbia spp. Water-independent.
May push over other tree spp and may convert a dense shrub thicket into open dwarf shrublands.

67. Impacts of White Rhino Ceratotherium simum
Impacts similar to that of hippos- convert medium tall grass spp to short-grass communities.
Sheet erosion is prominent in the sparsely grassed areas and gullies also expand in extent.
Requires water to be close by. Sometimes eats soil to obtain minerals.
The effects of the large ungulates are accelerated by other factors such as fire frequency, rainfall received etc.

68. Interactions with Other Herbivores
Interactions of large herbivores on each other result from being potential competitors for food resources.
Effective competition results from sharing common food resources in short supply.
Compounded by responses to weather fluctuations or other external causes.
Interactions maybe thru facilitative grazing.
Either effect can be exhibited depending on vegn types, density ranges and time scales.

69. Determinants of Community Structure
The densities of plants & herbivores vary widely within & btwn yrs in response to enval fluctuations esp rainfall.
Natural popns of large savanna mammals are close to limits set by their food resources.
Close rln btwn total biomass of large herbivores and mean annual rainfall in wildlife areas receiving low-medium annual rainfall (Coe, Cumming & Phillipson, 1976)-Predict long term cc
Rln based on fact that primary prodn is positively related to mean annual rainfall.
y = 1.552X-0.62 where y= log total herbivore biomass (kg per sq km) and X= log mean annual rainfall (mm per yr)
Hypothesis: for most savanna ecosystems, it is possible to establish statistically sig.rlns which permit prediction from rainfall data of large herbivore biomasses, their prodn (secondary) and energy expenditure.

70. Deviations from Predictions
Bell (1982) modified Coe et.al’s prediction by suggesting that the total large herbivore biomass increases with rainfall on soils of high nutrient (volcanic) & medium content as mean annual rainfall increases from less than 200mm to about 820mm per annum.
On low nutrient soils (basement siltations & granitic shields, biomass increases with mean annual rainfall of about 700mm and then declines as rainfall increases further.
Bell showed that herbivore biomass/rainfall rln is modified by geomorphology thru its influence on the availability of soil nutrients.
Coe et.al had not included basement geology areas with rainfall > 800mm/yr.
Besides quantity of available plant biomass, herbivores are also influenced by the quality of the vegn e.g. the Miombo woodlands receiving mean annual rainfall of mm supported low herbivore biomass. Why is this so?

71. Classes of Savannas Tropical savannas fall into 2 distinct classes:
Arid, eutrophic- high soil nutrient availability, relatively low rainfall & low biomass of high quality vegn.
Moist, dystrophic- low soil nutrient availability, high rainfall & a high biomass of poor quality vegn.
Arid savannas support a high total biomass of large herbivores & moist support a low biomass of large herbivores.
Coe et.al’s tve rln btwn herbivore biomass & rainfall was for the arid, eutrophic areas.

72. Types of Herbivores
Arid savanna herbivores- biomass increases on highly nutrient soils with rainfall upto 820mm & declines as rainfall increases further. Dominated by grazers, mixed feeders and browsers like eles, zebra, buffalo, giraffe, black rhino, eland .
Moist savanna spp- show a linear rln btwn biomass & mean annual rainfall over the full range on soils of low nutrient e.g roan, hartebeeste, warthog, bushbuck, oribi, sable, waterbuck. Mainly highly selective grazers with low biomasses. Distinguished by showing tve correlation btwn biomass & rainfall even in high rainfall areas.

73. Savanna Spp From the rlns of individual herbivores, it can be
concluded that:
The total biomass of arid savanna species is tvely related to rainfall in arid, eutrophic savannas, but tends to decline with increasing rainfall in moist dystrophic savannas with no overall rln btwn biomass & rainfall apparent for low nutrient status soils.
The total biomass of moist savannas species shows a similar rln to rainfall for soils of high and low nutrient status over the full range of rainfall.

74. Points to Note About Rainfall/Biomass Rlns of Large Herbivores
tve correlation btwn total large herbivore biomass & rainfall (Coe et al., 1976) applies in general to individual herbivore spp (worked for 19 out of 23 herbivore spp).
Individual spp lack precision becoz estimates were based on short time intervals which can fluctuate in the long term in response to complex interactions btwn factors like weather, vegn, fire & other members of the herbivore community.
Total herbivore biomass rln is valid for individual reserves/parks but variations occur within habitats locally due to habitat preferences of spp- effects most pronounced for spp with narrow habitat preferences e.g waterbuck which prefer riverine areas, also oryx and Grant’s gazelle adapted to arid conditions.
Low total herbivore biomass in moist, dystrophic savannas of West Africa although caused by vegn quality may also be due to hunting pressure & intense human use of west African savannas.

75. Mgt of ungulates
Resource managers use research findings to intervene in community ecology. Debates surround various types of mgt activities- utilitarian to preservationist approaches.

76. Case Study 1- Tsavo NP
When Kenya’s Tsavo NP was established in 1948, it was densely vegetated with eles & rhinos major attractants.
Pple were evicted from land & wildlife viewing was the only permitted land use.
Managers took a hands-off approach- let nature take its course expecting that the park wld continue to support trees, eles and rhinos.
Late 1950s, evidence of habitat degradation from eles but mgt argued it was part of the natural cycle- continued with minimum intervention until severe droughts in 1960 & early 1970 resulted in thousands of rhinos and eles dying.
By 1973, grasslands replaced woody vegn & grazing spp e.g zebra, gazelle increased.
Parks are characterised by too many wild animals and high human-wildlife conflict.

77. Case Study 2- KNP
In South Africa’s Kruger NP.managers followed a strategy- human intervention to control the balance of nature by culling lions, eles and ungulates.
Construct water supplies, burn vegn & control diseases.
Actions aimed at maintaining original habitats and spp.
Highly manipulative style exploring eqm thinking.

78. Case Study 3- Sustainable Utilization
Based on sustainable ecosystem approach seeking to integrate resource conservation with use.
Does not focus on products but on conserving the processed that sustain healthy ecosystems.
Grounded in the flux-of-nature viewpoint with people an integral part of the flux.

79. Carrying Capacity
Land, water & other NRs in any area can only support a limited no. or density of pple, cattle or other animal spp.
Defns:
Max no. of individuals of a given spp that a particular env supports sustainably (without deterioration of habitat) assuming that there are no changes in that env.
No. of animals of a given spp that can subsist on a unit area and produce at a required rate over a specified period, usually a season, yr or longer.
Maximum possible stocking of herbivores that an area can support on a sustainable basis (FAO, 1998).
Rate of forage production = forage consumption
Popn is in eqm with its env.

80. Managing CC
CC may be increased by investment or mgt, but still sets limit to popn size or level of economic activity.
Thus CC is a fn (determined by many factors) of:
veld or pasture mgt ii. Trampling effects
Water-point distribution
Food supply
Availability & amount of palatable and nutritious plant species
vi. Competition
vii. Animal behaviour etc.

81. Effect of Food Quality & Quantity
Factors relate to food intake, based on the energy requirements & ability to fulfil them.
The inverse rln btwn unit live mass & quality of preferred diet implies capacity of a rangeland to support ungulates is expected to be highest for large, BRE and least for small CS
Prediction also based on live mass & dietary quality and quantity affecting social org.- smaller animals requiring conc food are less gregarious than large ungulates which tolerate fibrous food.
How does body size affect capacity to support ungulates?

82. Body Size & CC
Capacity to support ungulates is high for large sized and largely grazing spp and low for small sized & mainly browsing spp- social org, habitat specific etc.
Although grass is of low quality, it is abundant on African rangelands & high quality browse is limited.
Note: food is not the only limiting factor to ungulate popns, but its an important factor limiting popn growth.

83. CC of habitat
Eland
Buffalo
Giraffe
Live
mass
Selectivity
In feeding
(BRE)
Oribi
Dikdik
(IF)
Steenbok
(CS)
Requirement for conc food
Diagrammatic presentation of CC of grasslands & woodlands for ungulates in relation to
Live mass, relative requirement for conc food & selectivity in feeding.

84. Basis for CC
Exponential growth curve not biologically realistic- no popn can grow indefinitely.
Env not constant & resources such as food & space are limited.
Logistic growth pattern shows the natural limits to popn growth.
At low density, popn grows uninhibited in exponential way & growth decreasing as resources become more limiting.
At maximum densities, the popn approaches a stable eqm limit, K the CC.
Recall the eqns for the logistic and exponential growth patterns.

85. Logistic Growth Pattern
The multiplier ([K-N/K] or [1-N/K]) is the unutilised opportunity for popn growth.
Differential eqn for the logistic curve implies:
rate of increase of a popn over a unit of time =
Potential increase of popn*unutilized resources.
When N is low, multiplier approximates 1 as most of the resources are unutilized.
When N approaches K, multiplier approximates 0 as most resources are utilized.
If N>K, then dN/dt becomes –ve and N declines towards K.
What are the assumptions of the logistic growth pattern?

86. Types of CC
There are 2 types of CC illustrated by overview of rln btwn plant & wild herbivore popns at alternative stocking densities.
Economic CC
Animal biomass/
Unit area or
Standing crop of
animals
Offtake curve
Standing crop of plants

87. Cont’d
Offtake curve (sustained yield) represents the different levels at which animals can be harvested.
Depends on rate of increase.
Doesn’t mean holding popn at ecological CC as rate of increase is zero then.
The maximum sustained yield (MSY) occurs when growth rate of herbivore is at maximum.
MSY intercepts isocline curve at about ½ to 2/3 of stocking density at K- economic CC.

88. Types of CC cont’d
Top curve marks all technically feasible combinations of plant & animal densities in a hypothetical grazing system.
Far left of horizontal axis shows a habitat with a small herbivore popn & a large standing crop of plants- most botanically rich position with greatest spp diversity & vegetative biomass.
As animal popn increases, edible plant biomass declines. In an undisturbed grazing system, the increase in animal numbers will eventually be checked by declining availability of natural forage.
Prodn of forage = rate of consumption (K or ecological CC).

89. Characteristics of Ecological CC
Rate of prodn of edible forage= rate of consumption by herbivores.
Neither herbivores nor the rangeland are in a good condition.
Animals’ death rate = birth rate.
Pure preservationist’s understanding of CC.
Ecological CC= Max CC= Potential CC=
subsistence density

90. Characteristics of Economic CC
Commercial or financial optimum.
Value of total offtake minus prodn costs is maximized.
Animals have a reproductive and survival rate.
The animals are in a good condition.
Fewer animals than ecological CC which are healthier with dense vegn.
Understanding of CC by livestock and game ranchers.
Optimum density= Economic CC

91. Importance of CC
CC means interpreted differently depending on goal- livestock prodn, habitat conservation or wildlife mgt.
Methodologies for estimation may provide reliable estimate in one ecological zone and less reliable figures in a region with greater annual forage variability.
Despite conflicting interpretations CC is central to conservation & wildlife mgt because:
Where the goal is conservation for non-consumptive use, the difference btwn the CC estimate and actual density provides index of conservation success & effort required in law enforcement.
Cc estimate provides indication of area’s potential for tourism.
Where goal is consumptive use, CC estimate contributes to determination of sustainable offtake quotas & economic potential for harvesting.
Where goal is regulation/control, CC estimate indicates effort & cost required to reduce popn to specified level.

92. Assumptions for Estimating CC
Commonly based on assumption that livestock require a daily dry matter intake (DM) equivalent to 2.5-3% of their metabolic body weight.
To increase accuracy btwn forage supply & demand, 3 quantities must be adjusted for:
Grazing efficiency (proportion of total herbage harvested).
Forage loss (trampling & decomposition). In arid lands up to 50% of annual prodn is lost.
Proper use factor (PUF)- maximum proportion of forage grazed without rangeland deterioration. PUF has many uncertainties, allowable use factor (AUF) is used- 30 to 50% of herbaceous biomass.
NB. These parameters are difficult to determine for wild ungulates & other approaches have been proposed to estimate CC.

93. Methods of Estimating CC
1. The Analytical Approach
Aims at constructing est based on the components of the plant-herbivore system e.g. maintenance, growth requirements, basal heat prodn of diff herbivores & the quality of the vegn under various conditions.
Challenges:
Converting vegn prodn est into animal stocking rates.
No simple rln btwn total plant prodn & herbivore prodn (affected by quality, herbivore preferences etc.)
Ability of herbivores to convert vegn into animals biomass differs according to digestive physiology, body size etc.

94. 2. Comparative Approach
Based on assumption that areas with similar physical & biological features have similar CC.
Compare area with unknown CC with known.
Depends on 2 sets of factors:
Methods of classifying land units to assess similarity shld be correctly identified- vegn types, rainfall, soil type, surface water availability.
Correct measurement of animal biomasses to be stocked.
Challenges:
a) est of wildlife densities & biomasses are usually inaccurate & unreliable.
b) Most areas are subject to an unmeasured illegal offtake in addition to legal offtake, thus many areas don’t meet logistic growth assumptions.
c) Variable spp composition will result in some spp being absent from faunal composition.

95. 3. Manipulative Approach
Based on the idea that the response of plant herbivore system to manipulation (increase or decrease in offtake) can determine the shape of the zero isocline & where potential CC is.
Human intervention determines eqm & numerous equilibria are possible, depending on the mgt goals & levels of animal harvesting prescribed by these goals- characterised by lower no’s of herbivores & higher levels of accessible forage biomass than at the subsistence density or ecological CC.
Makes use of system models to est CC as the whole system is monitored for change in response to some form of manipulation in order for the particulars of the model to express themselves.

96. Manipulative approach cont’d
Advantages
Contributes to an in-depth understanding of the system.
Embodies the concept of adaptive mgt & uses mgt activities to improve conservation methods.
Provides info on harvesting rates which is often the reason for estimating CC.
appropriate for progressive fine tuning of the CC est after a broad est has been made using the comparative approach.

97. Complications in Applying CC
Eruptions- popns exceed CC when suddenly released from a constraint (hunting, H2O shortage or competition). Super abundant food supply & increases rapidly.
Oscillations- plant-herbivore rln results in stable limit cycles as there is a slow mutual response btwn the 2 resulting in prolonged oscillations.
Variability in savanna ecosystems- climatic, resource dynamics, ecosystem resilience, spatial variability, mgt objectives. Works in relatively stable temperate envs.

98. Complications Cont’d
d. Enval fluctuations- plant & animal densities vary within & btwn yrs in response to enval fluctuations esp rainfall.
e. Emigration/immigration- influence eqm point. If animals are prevented from dispersing or forced to immigrate into an area, vegn is eroded leading to a crush or oscillations.
f. Predation- shld be known as it affects eqm position.
g. Interaction with other herbivores- spp interactions may be competitive, facilitative or have either effect on diff vegn types, density ranges and time scales.
h. Economic considerations- MSY is the most economic but other strategies give different views of CC.

99. Overpopulation
The zero-isocline curve indicates many points that can be perceived as optimum positions depending on mgt objectives.
Makes no sense to loosely talk about over-popn or over-exploitation of any resource.
Subjective as they indicate a particular viewpoint that may not be shared by others.
Term shld not be used independently, but the goal & purpose of exercise shld be stated.
Loosely, over-popn is having too many animals.
Important to know in what sense an area is overpopulated.

100. Classes of Over-popn
4 classes that are not exhaustive have been identified.
Animals threaten human life or livelihood- eg. Eles, baboons, mosquito. Presence inconvenient. Perception not shared by one unaffected. Human-wildlife conflict.
Animals depress densities of favoured spp
Animals too numerous for their own good- justification for sport-hunting.
System of plants & animals is off its eqm- ppn eruptions, habitat degradation. Based on ecological principles.
NB. Other classes usually erroneously presented as e.g. of last class.

101. Mgt of Locally Abundant Animals
Result of lack of predation & prevention of dispersion caused by fences or pple & associated activities close to park boundaries.
Cause habitat degradation.
Ele mgt in Zim has been well-documented in the principal ele ranges in the country (Mat N, Zambezi valley, Gonarezhou, Sebungwe etc).
Ele distr known due to aerial surveys &/or road strip counts.
Annual surveys done under the ELESMAP (Ele Survey & Monitoring Program)- regional program that harmonizes survey methodology & timing amongst the principal countries.
Zim popn above based on dry season surveys done when visibility is good & ele range is at its smallest.
Major culling operations done until 1989 & poaching in Zambezi valley stopped (Operation Safeguard Heritage) btwn % ppn increase , now 5% (redn poaching, no culling etc)

102. Key Ele Mgt Issues Impacts of eles on vegn
Ivory stockpiles- security, database mgt.
High costs of successfully protecting eles.
Maintenance of sustainable artificial water supplies.
Competition from other land use options.
Social rationale
What solns can you propose to these mgt problems?

103. CITES, Zim & Eles
African ele 1st listed under appendix II in 1978 & a quota system on ivory was established in 1985.
From , Zim exported about 100tonnes of ivory to the international market.
Illegal trade, smuggling overshot legal trade resulting in the 7th COP (Luisanne USA, 1989) putting back African eles on Appendix I.
Zim, Bots, Moza, Zambia & SA objected to the listing. Zim’s ppn was estimated at
At COP 10, June 1997 in Harare, Zim & other countries successfully won their proposal to downlist African ele because:
Best interest of elephant conservation
Would assist rural communities
Ban on ivory trade is punishment for ele conservation successes
Culling & related products benefit conservation and people.

104. Cont’d
Zim managed to sell 20t of raw ivory to Japan in 1998, but next proposal failed for Zim at COP 11 in Kigiri, Kenya- failed to meet MIKE stds.
In 2002 (COP 12) in Santiago, Chile, Zim failed but Bots, SA & Namibia were allowed to sell.
In Bangkok, Thailand (COP 13), Zim did not submit a proposal.
In the Netherlands, COP 14 Zim was not successful.
Zim was not selling to the international market bt to the domestic market.
What happened in 2010 at COP 15 in Quatar?

105. Case Study- Ele Mgt in HNP
HNP covers an area of sq.km & is cut off from the Zambezi river in the N & Gwayi in the east.
Annual rainfall is 630mm in the east & 400mm in the west. Kalahari sands cover about 2/3 of the park & support a diverse woody vegn ranging from Baikaiae plurijuga teak, Pterocarpus angolensis mukwa & Terminalia shrublands & narrow vleis in shallow depressions.
Communities are influenced by past logging, frost, fire & eles.
Remainder of the park is characterised by shallow basalt soils supporting C mopane & Combretum woodlands. Sodic soils are in the N-E.

106. Ele mgt in HNP
Aerial counts done annually, road strip counts & water hole counts. 5% growth model assumed beginning with 250 eles in 1930.
Ele problem was recorded in early 1960s & 1st culling operation took place in 1966 &1967 when 278 & 500 ele were killed from an est 5000 animals.
In 1971, popn was at & decided to remove 3000 of which 1364 was removed & operation contd with varying nos until 1986.
Policy adopted after 1974 was to maintain popn at
Culling was done in most susceptible habitats- edges of Kalahari sandveld & rainfall resulted in recovery of vegn.
A total of eles were culled until operation stopped in intl conventions, shortage of $ & manpower.
Critical issue is seasonal extremes of ele distribution e.g. in a survey 55% of eles were in 7% of the park & densities range from 2.4 to 16 eles/km2.

107. Policy & Options
Waterhole manipulation could spread eles, but soil features of some areas affect water quality.
Manipulation of water points was frustrated by war & currently by debates on impacts & lack of $.
Cont’d increase in ele no’s & habitat degradation require culling but intl regulations will resulting high costs being incurred which won’t be abated by revenue generation.
Limited habitat range rules out translocation.
Presently studies focus on vegn monitoring exercises & impacts on other herbivore popns.

108. Wildlife Censusing Techniques
Why count animals?
How many animals (animal popn)?
Where are they found?
When are they found?
Animals can be counted from the air or ground.
They are 3 broad methods- total count, sample count & index count.
Within each method they are different techniques & no ideal one since each has advs and disadvs in different situations.

109. Total Count/True Census
Direct count of all individuals in an area.
Ideal for territorial spps which are easily seen & heard and can be located in a specific areas.
Normally used for birds e.g. Intl. waterfowl census, roosting sites & breeding colonies.
Advs- gives true popn of spp.
Disadvs
More expensive than sample counts- impractical for large areas.
Level of precision can not be measured.
Time consuming in large areas.

110. Sampling Estimates Involves 2 basic assumptions:
Mortality & recruitment during the period of data collection are negligible or can be accounted for.
All members have equal prob of being counted & do not group by age, sex or some other characteristic.
Problem with assumptions- animals tend to occur in groups which are randomly distributed e.g. favour certain habitats, visibility varies, type & state of habitat, animal behaviour (large groups are difficult to count.
To accommodate these problems, area is divided into blocks or transects ( sample units) which are searched & counted after careful planning to account for uneven distribution.

111. Advantages & Disadvantages
Cost efficient & results more accurate esp if sample area is defined by a set of transects.
Navigation is simpler if area is stratified prior to the survey into density classes (high, medium, low)- obtain results with greater precision.
Precision can be measured.
Disadvs
Low levels of sampling result in low precision.
Require higher level of preparation & greater understanding of techniques being employed.
Level of random sampling error i.e. level of certainty or confidence on estimate e.g. 95% C.I for popn is % means that there is 95% confidence that true popn lies btwn 400 & 600 animals. Large C.I- result is imprecise..

112. Aerial Surveys
Area 1st divided into strata (subdivisions)- stratified survey.
Strata boundaries are drawn using previous survey results & knowledge of area.
Stratification increases precision of popn est & sampling intensity varies depending on where more eles are expected to be found.
Surveys are flown during the dry season when most trees are leafless & visibility is good.

113. Aerial Surveys
Parallel transects cut across enval gradients e.g. across rivers, valleys, hills etc.
1st transect is randomly located & distance transects vary with planned sampling intensity.
Ele carcasses are put in categories:
Fresh: intact, vulture droppings visible, vegn trampled, fluid stain on ground still visible. Likely to have died in last 3 mnths.
Recent: pieces of hide still attached. Skeleton partly seen. No vulture droppings & no trampled vegn. No fluid stain evident. Less than 1yr but since last rains 3-8 mnths.
Old: bones scattered & bleached. Probably died during or before last rains i.e. more than 8mnths & generally more than1yr & upto several yrs old.

114. Requirements for Aerial Survey
Light aircraft with a radar altimeter (measures ht) & GPS.
Pilot, recorder in co-pilot seat & 2 observers.
Plane flies at 300ft (91.4m) above round level.
Each observer searches for eles in a strip of abt 150m wide. Other large animals are recorded such as buffalo, sable, giraffe, waterbuck, zebra eland as well as ele carcasses, poachers’ camps and domestic animals if census is outside NP.
Smaller spp distributions are mapped & useful indices of abundance obtained.

115. Advs and Disadvs
Advs:
Quick and efficient for extremely large wildlife areas.
Do not depend on ground access to the area.
Disadvs:
Expensive & require skilled personnel & ideal observers shld be willing, experienced, have good eyesight & are immune to air sickness- speed of aircraft, transects width & skill of observers have sig. effects on popn estimates.
Aircraft crashes are usually fatal.
Not useful for smaller antelopes and predators.

116. Line Transects/Walked Transects
A transect or line of known length is set out randomly in an area.
Transect is walked & individual animals are observed along the line.
Line transect method provides an index rather than absolute measure of density. Varied so that animals on either side of the line are noted & perpendicular distance from line to point of sighting (sighting/flushing distance) & sighting angle measured.
Technique is then referred to as distance sampling.
2(Average perpendicular distance)* transect length= Area
Density in transect= no. of animals/area
Popn size = density* total area
NB. Data can be fed into a computer program TRANSECT or LINETRAN for easier calculation.

117. assumptions Animals are always seen- detection prob is 1.
Animals don’t move before being sighted & none is counted twice.
Sightings are independent events.
Distances & other measurements are accurate (Compass, anglometer and rangefinder).

118. Advs & Disadvs Advs: Easy to use and relatively cheap.
Walked transects allow for a greater range of animals to be seen.
Allows for the participation of more pple.
Disadvs:
Defining a straight line is a problem.
Getting accurate measurements of distances & angles.
Observers are in close contact with wildlife which is potentially dangerous.
Needs a lot of transects & pple for sample area & proportion of total area not to be very small.

119. Road Strip Count
Vehicle used in a selected network of roads in the wildlife area.
Observers sit at the back of the vehicle & count all animals seen & measure sighting distance from road & sighting angle.
Sample area is calculated from as in walked transects. If size of area is known, total popn can be estimated. Computer package DISTANCE can be used for analysis.
Advs: provide est for most spp than aerial surveys.
Disadvs:
need a well established road system.
Road system shld cut across all habitats
Analysis can be complicated.
Vehicle makes it relatively expensive.

120. Mark-Recapture Sampling
Based on trapping, marking & releasing a known no. of marked individuals into the popn & later recapturing individuals from the popn after an appropriate interval of time/ re-observation without actual recapture.
Sampling provides info on the recapture of marked individuals & proportions of marked & unmarked individuals captured at each sampling time.
Estimate of total popn obtained from ratio of marked to unmarked individuals in the sample which reflect the same ratio for the popn.
NB. Estimate is for time the marked individuals are released in the popn and not the time of recapture.

121. Assumptions All individuals have an equal chance of being captured.
Ration of marked to unmarked individuals remains the same from time of capture to time of recapture.
Marked individuals redistribute themselves homogenously thruout the popn with respect to unmarked ones.
Marked individuals do not lose marks.
The popn is closed (no emigration or immigration).
N.B as popns are dynamic, researcher shld know features of the popn and adjust accordingly. These include reproductive history, mortality patterns, effects of marking on animal behaviour, patterns of mvts & bias of age and sex on prob of capture.

122. Lincoln-Petersen Model
N:M::n:R equivalent to N/M=n/R or N= nM/R Where: M= no. of marked in the precensus R= no. of marked animals trapped in the census period. n = total animals trapped in the census period. N= the popn estimate. The prob of capture on any given occasion is: p= R/n SE= N* square root of (N-M)(N-n)/Mn(N-1) 95% C.I= N SE N.B: a large std error and wide C.I are a result of a small number of recaptures and a small sample size.

123. INDICES
Based on counts from animal signs (dens, burrows, nests, tracks), calls, roadside counts etc and give an indirect measurement of the status of the popn in the area.
Results do not give estimates of absolute popns, but indicate trends from year to year and from habitat to habitat.

124. Types of Index Techniques
Call counts- bird calls or audio playbacks.
Counting pellets or faecal groups
Index of abundance
Index of trophy quality
Index of hunting effort
Index of “hunting success rate”

125. Management Planning
The various challenges facing resource managers demand for planning in the mgt of the Parks & Wildlife Estate.
Planning is a strategic, operational, decision-making method that is systematic, comprehensive, accountable & efficient.
Takes logical steps, includes all relevant issues by including stakeholder participation.
Conducted at various levels (hierarchy of planning) resulting in different types of plans to be produced.

126. Types of Plans
Master plan for the Parks & Wildlife Estate- national strategy, gvt positions on mgt policy. Signed by responsible minister.
Mgt plans for national parks and other units- detailed guidance for the mgt of individual NPs/other units. Reviewed after 5yrs or sooner (adaptive mgt).
Annual implementation plans & budgets- describe how the mgt plans/activities are implemented in the coming yr & financial requirements.
Species mgt plans- spp of special importance. Guide national mgt of spp e.g. ele, rhino, croc, ostrich, wilddog etc.

127. Sections of Mgt Plan Role, process, monitoring & revision of plan.
Goals & objectives of the mgt unit.
Background info & current status- size, location, history, env, climate, topography, soils, water, vegn, wildlife etc.
Regional land use, park facilities & other land dvpts, land status, visitor use.
Zoning with guidelines for use & mgt.
Ecological mgt objectives & plans for vegn, water, fire, wildlife, monitoring & research etc.
Visitor use mgt, objectives & plans including facilities dvpt.
Law enforcement.
Infrastructure dvpt & maintenance.
Staffing
Financial mgt including expected revenues & expenditure.
Annexes & more detailed info on topics.

128. Steps in Mgt Planning Project initiation Issues identification
Formulate goals & objectives
Data collection
Identify & analyse options
Recommend & select preferred options
Prepare implementation strategies detailed plans.
Plan adoption
Plan production
Plan implementation & reviewing

129. Monitoring
Parks Estate managed according to the principle of adaptive mgt.
Links research & monitoring to mgt activities.
Assesses effects of mgt actions, monitors them & evaluates them in relation to intended objectives.
Future mgt actions are modified accordingly so as to achieve mgt goals & objectives.
Monitoring takes place on an annual basis for important programs & resources, & needed changes implemented the following yr.
For each resource or mgt topic, specify verifiable objectives, parameters to monitor to determine whether objs are met & limits of acceptable change in parameters.
If threshold levels are exceeded, mgt actions are changed accordingly- adaptive mgt approach.

130. Example of adaptive mgt process
Monitor /count popn
Set quota
Harvest quota
Monitor/count
Check no’s trends
Adjust quota accordingly
Restart process i.e. go back to counting

131. Monitoring Frequency
Monitoring provides feedback to management in time for action to be taken.
Long intervals between successive surveys diminish the possibility of understanding the changes that have occurred.
This is the basis of adaptive management.
Frequency of monitoring depends on:
Perceived rates of change in the ecosystem
Sensitivity of the areas or species
Availability of resources

132. CONCLUSION
Management should be based on making well-informed decisions.
Managers vary in their intensity of management.
Management is dynamic, goal-oriented and should be cyclic & incremental.
Large mammals should be managed by a resource manager who understands ecological principles and is willing to learn from the environment.
Mgt of large mammals has to a large extent been the backbone of wildlife mgt in Zimbabwe.