Strategies for Conducting Research Using an Integrated Approach to
Natural Resource Management
Many of the environmental challenges we face are
so complex that it almost seems impossible to identify the heart of the
problem, let alone identify and prioritize solutions, trade-offs, and potential
conflicts for the given problem. My advice is to always start by taking a step
back to attempt to see the 25,000 foot view before diving into the specific
problems. This type of approach enables you to identify all of the parts of the
problem before you start to understand each part individually and then together as
an entire system. This is often referred to as a systems approach with the goal
of ensuring that every perspective is considered and addressed throughout the
planning process. Another important aspect at this stage in the planning
process is to attempt to remain as open as possible to all of the information
you come across and evaluate each piece of information on its own merits. This
will allow you to remain as unbiased as possible during the information
gathering stage of the planning process.
At this stage of the game, you need to
understand what the issues are, who the stakeholders are, and what the
overlapping and competing issues that contribute to the issue at hand are.
Before you meet with a stakeholder group or attempt to identify and prioritize
the issues, it is pertinent to conduct a detailed assessment of the history of the
problem, identify the historical conflicts between stakeholders, understand past
planning efforts, and identify trends for the future. The following case
study is an assessment of the combined impacts of climate change and invasive
species on island ecosystems. It provided the necessary background information
needed to develop an integrated strategic plan that was later used to develop
projects for biodiversity conservation, as well as identify potential impacts
to island ecosystems from the combined effects of climate change and invasive
species.
This case study is a summary of the expected
impacts from climate change on islands, from invasive species on islands, and
their likely combined effects. Additionally, the assessment reviews the social,
political, and economic effects of both climate change and invasive species on island
biodiversity. This information was used to help inform the stakeholder
working group, set priorities that were rooted in science, and educate the
stakeholders so that they were contributing to the strategic plan in an
effective manner. Moreover, this type of inclusive assessment allowed us to
ensure that each stakeholders concerns and needs were taken into consideration
during the strategic planning process.
As usual, I welcome your comments or questions. Thank you, Gabrielle
Outlining the Combined
Effects of Climate Change and Invasive Species on Islands
Expected Impacts from Climate Change
to Marine Life and Small Islands
·
Many important coastal habitats that provide
benefits to human society and the environment alike are also highly likely to
experience severe declines.
·
Higher sea level and warmer ocean temperatures
can alter ocean circulation and current flow, increase the frequency and intensity
of storms, alter habitat, and impact weather worldwide (Baker et al. 2008,
Carpenter et al. 2008, Bakun 1990, Nicholls et al. 1999, and Bindoff et al.
2007).
·
Despite the differences in erosion potential
along the world’s coastlines, there has been a dramatic increase in coastal
erosion over the last two decades (Morton et al. 2004) and this is expected to
continue as sea level rises (Brown and McLachlan 2002) and storm frequency and
severity increase.
·
Rising sea level is most threatening to low
lying island nations and the delta populations of South and Southeastern Asia
and the Nile Delta in Africa (Nicholls et al. 2007 and Nicholls et al. 1999).
·
Many climate change impacts are likely to affect
island communities in both the Caribbean and Pacific, including higher sea
levels, more powerful tropical storms (such as hurricanes in the Atlantic and
typhoons in the Pacific), and warmer, more acidic coastal waters. Unique island
ecosystems, such as coral reefs and mangrove forests, are already facing stress
from human development and pollution, making them particularly sensitive to additional
stresses from climate chance (USGCRP 2009).
·
Islands are home to unique ecosystems and
species that provide economic opportunities, safety, nourishment, and cultural
value to island communities (USGCRP 2009 and Mimura et al. 2007).
·
The loss and inundation of other coastal
habitats, such as mangroves, from sea level rise and storm surge could endanger
species that use these habitats for nesting, nursing, and nutrients (USGCRP
2009).
·
Climate change may enhance conditions that facilitate
the spread of invasive species and marine and terrestrial pathogens and
diseases, which would affect and island’s natural ecosystem and biodiversity
(Mimura et al. 2007).
Impacts from Invasive Species on
Island Ecosystems
·
The Earth has approximately 100,000 islands many
of which are important biodiversity hotspots made up of fragile ecosystems that
are home to some of the most unique species in the world (CBD 2010). Island
ecosystems are key areas for biodiversity conservation worldwide since they
represent less than 5% of the planet’s land mass, yet are home to 39% of
critically endangered species (Whittaker 1998, Diamond 1985, 1989, Olson 1989).
Island species are more susceptible to environmental stressors that cause
extinctions as a result of their small population sizes and limited habitat
availability. In addition, island species have adapted in isolated environments
making them particularly vulnerable to impacts from invasive species (Diamond
1985, 1989, Olson 1989).
·
It is widely accepted that the natural world is
facing a very high rate of species extinction (Raup 1988), that most recent
extinctions can be directly attributed to human activity (Diamond 1989), and
that for ethical, cultural, aesthetic, and economic reasons this current rate
of extinction is cause for considerable concern (Ehrlich 1988, Ledec and
Goodland 1988). One of the major worldwide causes of anthropogenic extinctions
is the introduction of invasive species. Of the 245 recorded animal species
extinctions since 1500, 75% were species endemic to islands (World Conservation
Monitoring Centre 1992). Invasive species were at least partially responsible
for a minimum of 54% of documented island extinctions, based on the 170 island
species for which the cause of extinction is known (Ricketts et al. 2005).
·
The effects of invasive species on islands
accounts for 80% of all species extinctions recorded so far. Half of these
recorded extinctions were caused by invasive alien vertebrates (IAV) such as
rats, mice, pigs, goats, etc. Rodents (rats and mice), the most prolific of all
invasive vertebrates, are estimated to have been introduced to more than 80% of
the world’s islands as the result of human activities. Invasive species
continue to invade new islands today with the ever-increasing movement of
people and goods around the world. When introduced to islands, invasive species
upset an island’s natural equilibrium and severely impact native plants and
animals that lack adaptations to protect themselves from the intruders. There
is a relatively simple, efficient, and cost effective solution to this
island-species extinction crisis: when invasive species are removed from
islands, native plants, animals, and ecosystems recover with little or no
additional intervention. Combined with effective biosecurity, the eradication
of invasive species is one of the most effective ways to protect threatened
island biodiversity.
How do Invasive Species aggravate the
effects of Climate Change on biodiversity?
·
Climate change and invasive species are
considered by many scientists to be the greatest threats to biodiversity by the
21st Century. Climate change is projected to negatively impact
global GDP by as much as 20%, while invasive species are expected to impact the
GDP by as much as 5% of the global economy in the coming years. The combined
effect of climate change and invasive species is estimated to be around 25% of
the global economy by 2050 with the greatest impacts expected to occur on small
islands (Burgiel and Muir 2010).
·
The effects of invasive species are expected to
be exacerbated with a changing climate by creating conditions that favor
species that are highly adaptable and resilient to change, like invasive
species (UNEP 2006). For example, Hellman et al. 2008 found that extreme
weather events, shifting currents, and altered circulation patterns could
enhance invasive species ability to disperse to new areas where they will
likely have an advantage in overcoming biotic constraints and outcompeting
native species. Researchers in New Zealand are concerned that invasive mammals
like black rats, which are key drivers of the extinction rates of native
species, are highly likely to adversely impact biodiversity conservation and
ecosystem function with the combined effects of climate change (Tompkins et al.
2013). The Australian Invasive Species Council has identified five likely
combined effects of climate change and invasive species to the native biota in
Australia including the following (Invasive Species Council 2009):
1.
Range changes due to new temperature and
precipitation patterns
§
Hill et al. 2013 has determined that climate
change is decreasing the productivity of Antarctic krill by decreasing the
overall concentration of chlorophyll-a. Antarctic krill accounts for
approximately 85% of Antarctic fur seal, 76% of grey-headed albatross, and 12%
of wandering albatross diets. Any degradation of Antarctic krill growth habitat
is likely to have consequences on predators on South Georgia Island, which
could cause serious declines in their population.
2.
Increased opportunity for invasive species
incursion into new areas during extreme or abrupt weather events
§
Cook et al. 2010 has linked the glacial retreat
on South Georgia Island with the increased incursion rate of rats into
previously unoccupied areas of the island as a direct result of glacial retreat.
This risk has serious implications for the important breeding populations of
ground nesting seabirds on the island.
3.
Increased susceptibility of native species to
invasive species
§
A USGS 2006 report has determined that native
Hawaiian birds are being decimated by avian malaria and pox transmitted by
introduced mosquitoes. Invasive feral pigs exacerbate the problem by providing
habitat for mosquito larvae by feeding on tree fern trunks. It has been
determined that by reducing artificial larval habitat and removing feral pigs
the mosquito population will be effectively reduced, which is the best hope for
limiting disease transmission.
4.
Increased chance of biosecurity breach with
human responses to climate change
§
There are few if any documented cases of
incursion as a result of conservation or restoration efforts; however, humans
are the primary cause of the spread of invasive species. Witmer et al. 2011,
summarized some of the reasons why human caused incursion are likely to occur:
·
People often cannot distinguish between native
and invasive species
·
People are unaware of how their quality of life,
economy, biodiversity, and conservation can be significantly affected by
invasive species
·
Many people believe in the sanctity of all life
whether invasive or not and do not want invasives removed
·
Many people have an inherent dislike or distrust
of the use of chemicals and toxicants even though they may be necessary tools
for invasive species management
5.
Increases in carbon emissions by removing native
vegetation that sequesters carbon
§
Godson 2008 assessed the risk that invasive
rabbits have on vegetation in Australia and evaluated their potential to
decrease carbon sequestration. Research found that 2 rabbits per hectare can
decrease plant regeneration by 75%. Furthermore, there are concerns that an
increasing rabbit population will create a high risk of rabbits consuming
seedlings that were planted for carbon sequestration.
·
Climate change is also likely to shift predator
prey behavior through habitat modification, rising sea temperatures, ocean
acidification, shifting marine and terrestrial community structures, and
altered migratory patterns. These projected changes can lead to prey switching
potentially increasing the threat to native species from both climate change
and invasive species.
1.
Iverson et al. 2014 recorded drops in prey
fitness under changing predatory pressures. In particular, they found that
polar bears were increasing predation pressure on Arctic seabirds with the loss
of suitable marine mammal prey.
2.
These types of shifting patterns that are likely
to affect all migratory and marine species will be exacerbated by the negative
effects of invasive species. Furthermore, it is predicted that the multiple and
varied effects of climate change will affect every pillar of biodiversity and
that sensitive species, that are often found on islands, are likely to exceed
their ecosystem thresholds or “tipping point” potentially resulting in
extinction (Rinawati et al. 2013). Species that have reached a tipping point
can respond in three ways: change, move, or die.
·
In order to minimize the likely outcome of many
island dependent species from reaching their ecological tipping point, an
integrated holistic approach to conservation and management of climate change
and invasive species is essential to increase the resilience and adaptability
of native species (Burgiel and Muir 2010). The Global Invasive Species
Programme identified three key messages that are fundamental in integrating invasive
species and climate change impacts across multiple sectors and regions. The key
messages include (Burgiel and Muir 2010):
1.
Climate change will have direct and indirect
impacts that will facilitate the introduction and spread of invasive species,
2.
Invasive species will likely increase the vulnerability
of ecosystems to adapt to other climate related stressors, as well as reduce
their carbon sequestration potential, and
3.
Using an adaptive ecosystem based approach, the
above pressures can be offset by preventing the introduction of new invasive species
and by eradicating and controlling the invasive species that are already
present.
·
Eradicating invasive species from islands will
have tremendous benefits for native species that are combating the combined
effects of invasive pressures with a changing climate. Stress is one of the
leading causes of species extinction and by eradicating invasive species from
islands, multiple stressors will be relieved simultaneously. Invasive species eradications
have a twofold benefit to impacted species by decreasing the direct and
indirect effects of invasive predators and increasing overall resilience of
biodiversity in the face of a changing climate.
