Forest Management in an Era of Biotic Homogenization

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Forest Management in an Era of Biotic
Homogenization
Zafar A. Reshi Department of Botany, University
of Kashmir, Srinagar-190 006 Jammu Kashmir,
India E-mail zreshi_at_yahoo.com
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PROLOGUE

• Biological invasions are a key component of
  global environmental change .
• Ranked as second major threat to biodiversity
• Alter structure and function of ecosystems
• Cause Biotic Globalization ( or Homogenization)
• Cause heavy ecological and economic damage which
  is estimated as US 1.4 trillion per annum
  close to 5 of GDP (GISP, 2009) and 12 billion
  per year for Europe (Kettunen et al. 2008)

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• What is Biotic Homogenization?
• Biotic homogenization (or BH) refers to the
  process by which the genetic, taxonomic or
  functional similarities of regional biotas
  increase over time. It is a multifaceted process
  that encompasses species invasions, extinctions
  and environmental alterations, focusing on how
  the identities of species (or their genetic or
  functional attributes) change over space and
  time.

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• Genetic homogenization
• It is used to describe an increase in the genetic
  similarity of gene pools over time resulting from
  intra- and inter-specific hybridization.
• Genetic homogenization via the dilution of native
  gene pools by invading exotic genes may be
  pervasive, and is likely to be associated with a
  number of ecological and evolutionary effects.

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• Taxonomic homogenization
• It refers to an increase in the phylogenetic
  similarity of biota over time owing to the
  establishment of cosmopolitan species and
  extirpation of endemic species.
• Taxonomic homogenization has been the primary
  focus of previous research and is used
  interchangeably with the term biotic
  homogenization throughout the literature.

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• Functional homogenization
• It is defined as an increase in the functional
  similarity of biotas over time associated with
  the establishment of species with similar roles
  in the ecosystem (e.g. high redundancy of
  functional forms or traits) and the loss of
  species possessing unique functional roles.

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The ecological and economic damage due to IAS is
the rationale for the selection of Trends in
Invasive Alien Species as one of 22 Headline
Indicators to measure progress towards the
Convention on Biological Diversitys target of
reducing the rate of loss of biodiversity by
2010. The framework for assessing progress by
2010 has seven focal areas with goals and
sub-targets for each area, as well as a number of
Headline Indicators.
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• Headline indicator Trends in invasive alien
  species
• Trends in what?
• Number of alien invasive species per country
  across different ecosystems
• Number of IAS-management plans in place (per
  country)
• Number of countries party to IAS-relevant
  international agreements
• Targets under the indicator are
• Pathways for major potential alien invasive
  species controlled
• Management plans in place for major alien
  species that threaten ecosystems, habitats or
  species

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• IAS and forest ecosystems
• Invasion ecology has traditionally focused on
  alien plant species with early successional
  life-history traits, adapted to colonize areas
  following disturbance.
• This focus neglects the types of plants most
  likely to invade established communities,
  particularly forests.

contd.
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• Key questions
• Are forests effectively immune to invasion even
  by alien species with late successional
  life-history traits, especially shade tolerance?
• Are late-successional plants essentially
  non-invasive, suggesting a fundamental trade-off
  between invasive and competitive life-history
  traits?

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Important Caveat
The early succesional dominance of invasion
ecology theory is overstated. Instead, many
alien species with late successional life-history
traits, especially shade tolerance have been
reported to be invasive.
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Source Martin et al. 2009.
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Database of shade-tolerant forest
invasives http//landscapeecology.agsci.colostat
e.edu/research/invasives/forest_invaders/forestinv
asives.html You can add additional species to
this database of shade-tolerant forest
invasives.
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We need to prepare a database of invasive alien
species STRUCTURE OF THE DATABASE

• Origin Native or Alien
• Historical records (scientific literature)
• Biogeographical studies (Centre of diversity)
• Evolutionary studies (Centre of origin)

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• Pathways and Vectors
• Intentional
• Released (Deliberately released into the wild)
• Escaped (Escaped into wild)
• Forestry, Ornamental, Agricultural, etc.
• Unintentional
• Unaided
• Transported Seed containments
• Minimum Residence Time
• (Earliest record of the alien species in
  scientific literature with correctly
• identified specimen cited and deposited in
  recognized herbaria and museums).
• Relevance for studies on lag phase and future
  prediction.

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• Stage of Invasion Stages II-V, with explicit
  mention of spatial scale.

• SPECIES INVASIVENESS
• Taxonomic affiliation
• Invasive elsewhere
• Mode of reproduction
• Mode of dispersal
• Propagule pressure
• Herbivory
• Allelopathy
• Growth form
• Mycorrhizal association

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• Elevational range
• Maxima and minima of altitude at which alien
  species is known to occur in India.
• Latitudinal range
• Information valuable for whether alien taxa
  occurs in Tropical,
• Subtropical, Temperate or Alpine climates.
• (Applications in spatial modeling and climate
  matching models)

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Taxonomic composition of the alien flora of
the Kashmir Himalaya
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Number of alien plant species at different stages
of invasion
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378
304
104
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Distribution of alien plant species in different
elevation zones
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Invasion process and management options
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Acknowledgements Organizers and sponsors for
financial support and invitation to attend this
workshop.
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Thank you