Forest cover and connectivity impact seed dispersal networks

Habitat fragmentation reduces connectivity in landscapes. This lowered connectivity can negatively impact seed dispersal, which relies on the ability of species to move (or be moved) through the landscape. In tropical forests, this impact can be observed in the interactions between frugivorous (fruit eating) birds and plants.

One way to measure this impact is phylogenetic diversity, which can be used as a way of quantifying the loss of evolutionary information that results from these environmental changes. Network interactions are another way to track the impact of environmental changes on communities. Habitat loss leads to declines in the amount of evolutionary divergence and influences the robustness of network interactions.

Monteiro, E.C., Pizo, M.A., Vancine, M.H. and Ribeiro, M.C. 2021. Forest cover and connectivity have pervasive effects on the maintenance of evolutionary distinct interactions in seed dispersal networks. Oikos. DOI: 10.1111/oik.08240.

The Atlantic Forest in South America is one of the top five global biodiversity hotspots in the world and the second largest rainforest in the Americas. Credit: Bjørn Christian Tørrissen

Well-preserved habitats ideally have more connections and/or interactions among species in a network or ecosystem. Networks with fewer interactions are at a higher risk for coextinction of species. Quantifying the impact landscape changes have on phylogenetic diversity and network interactions (essential to seed dispersal and other ecological processes) is imperative in order to make well informed management decisions.

A recent review examines how forest cover and functional connectivity impact the phylogenetic diversity of plants and frugivorous birds in the Atlantic Forest of South America. An analysis of journal articles, data repositories, and grey literature (such as theses and dissertations) shows that high forest cover correlates with high plant phylogenetic diversity. Additionally, high functional connectivity correlates with high bird phylogenetic diversity, and greater network robustness is observed in areas of high plant and bird phylogenetic diversity.

Phylogenetic diversity is a good indicator of biodiversity and ecosystem function, which are two goals of restoration and ecosystem management. Forest restoration efforts are essential to increase functional connectivity of landscapes. Forested areas with high functional connectivity have higher phylogenetic diversity compared to less connected or isolated forest patches. Considering fragment size, forest cover, and functional connectivity are important when making management decisions. This study provides evidence to support the importance of maintaining large forest patches and clusters of functionally connected areas with significant phylogenetic diversity that can ensure interaction networks with high levels of robustness.

State	Year	Policy	Description
New Hampshire	2026	SB592	Enables regional, conservation, and energy resource planning for habitat strongholds and wildlife corridors
New Hampshire	2019	SB200	Requires the New Hampshire Department of Transportation to consider fish and wildlife crossings and mitigation measures in all future road and culvert projects
New Hampshire	2016	SB376	Requires the fish and game department to identify existing and needed wildlife corridors connecting wildlife habitats in the state and to make recommendations for legislative changes

State	Year	Policy	Description
Maine	2023	LD258	Appropriates $7.5 million to Department of Transportation to improve roadways with potential adaptations for wildlife
Maine	2023	LD1881	Establishes compensation fee program relating to fish and wildlife habitats and associated corridors, including compensation paid by solar energy development
Maine	2023	LD508	Requires Department of Environmental Protection to review its permitting laws concerning climate change, habitat connectivity, ecological resilience, and coastal environments

State	Year	Policy	Description
New Jersey	2025	S3618	Directs state agencies to develop a Wildlife Corridor Action Plan
New Jersey	2024	S3916/A5486	Expands eligibility for existing wildlife fencing programs by including farmers leasing farmland
New Jersey	2007	NJAC7:13	Requires the state to incorporate wildlife crossings or a natural bank for terrestrial threatened and endangered species and/or species of concern when a new bridge or culvert project would cause habitat fragmentation

State	Year	Policy	Description
New Mexico	2023	SB72	Appropriates money to new Wildlife Corridors Fund for implementation of wildlife crossing projects under New Mexico Wildlife Corridor Action Plan
New Mexico	2022	HB 2	Allocates funding for projects to reduce wildlife-vehicle collisions and allows the Department of Transportation and Department of Game to implement their Wildlife Corridors Action Plan
New Mexico	2019	SB 228	Requires the creation of a Wildlife Corridor Action Plan that includes comprehensive guidance to agencies for identifying, prioritizing and maintaining important areas for wildlife movement

State	Year	Policy	Description
Washington	2023	HB1216/SB5196	Requires Department of Ecology to prepare environmental impact statements for clean energy projects that consider impacts to habitat connectivity and wildlife migration corridors
Washington	2022	SB5689	Provides funding for US 97 Wildlife Crossing Improvements project
Washington	2019	SEO 1031.02	Recognizes the effect of roadways in creating barriers to wildlife movement, breeding, and migrations; the Washington State Department of Transportation will promote and support Practical Solutions and Planning and Environmental Linkages to integrate habitat connectivity and biodiversity plans; will make use of the highway prioritization map known as Habitat Connectivity Investment Priorities; and will corporate and coordinate with other agencies involved in wildlife habitat protection, specifically along highways

Connecting Science to Conservation

Forest cover and connectivity impact seed dispersal networks

Monteiro, E.C., Pizo, M.A., Vancine, M.H. and Ribeiro, M.C. 2021. Forest cover and connectivity have pervasive effects on the maintenance of evolutionary distinct interactions in seed dispersal networks. Oikos. DOI: 10.1111/oik.08240.

Related Posts

About the Author: Hazel Anderson

State	Year	Policy	Description
Colorado	2026	SB141	Creates optional collision prevention fee to fund wildlife safe passage projects
Colorado	2025	HB1093	Restricts local limits on residential density unless offset elsewhere, exempts areas near wildlife crossings, and allows municipalities to seek judicial review of land use initiatives
Colorado	2023	SB 23-092	Encourages minimal impacts to wildlife migration corridors when constructing solar panel farms
Colorado	2023	SB 214	Appropriates funding to the Colorado Wildlife Safe Passages Fund for wildlife crossing projects
Colorado	2022	SB22-151	Creates a $5 million fund for measures that reduce wildlife-vehicle collisions and reconnect habitat fragmented by roads
Colorado	2022	HB22-1072	Expands the scope of Habitat Partnership Program to fund efforts to conserve wildlife migration
Colorado	2021	SJR 21-021	Aims to protect and enhance habitat connectivity in the state through the establishment of a working group to develop state policies on corridors, as well as the commission of a report on state corridors and voluntary policies to support willing landowners in improving connectivity
Colorado	2019	EO 11	Directs Colorado agencies to identify policy, regulatory, and legislative opportunities to ensure the ongoing conservation of seasonal big game habitat and migration corridors
Colorado	2018	SB 18-143	States explicit goals for Division of Parks and Wildlife to invest in habitat conservation and wildlife crossings

State	Year	Policy	Description
California	2026	SB1250	Requires the Department of Transportation (Caltrans) to include wildlife connectivity corridors and needs into its infrastructure project planning
California	2024	AB1889	Requires counties and municipalities to conserve wildlife corridors when planning new developments
California	2023	AB1760	Calls for a statewide analysis of wildlife corridors and connectivity to support conservation planning and climate change adaptation activities.
California	2023	SB145	Outlines provisions for transportation-related environmental mitigation, including funding for wildlife corridors, property and credit purchases for mitigation, reporting requirements, and mandates for wildlife crossings along Interstate 15.
California	2023	SB101	Provides funding for wildlife corridors and open spaces, including projects to improve connectivity and reduce barriers between habitat areas.
California	2022	AB2344	Establishes a state program to address roads with high wildlife-vehicle collisions, authorizes Caltrans to develop standalone wildlife connectivity projects, mandates an inventory and prioritization system for critical areas, and requires integration of wildlife passage features into relevant road designs.
California	2022	AB1384	Requires agencies to address vulnerabilities in Safeguarding California Plans, including protecting and enhancing wildlife corridors
California	2021	SB790	Approves compensatory mitigation credits for wildlife connectivity actions
California	2021	AB1183	Establishes the California Desert Conservation Program to protect biodiversity, including the protection and enhancement of habitat connectivity
California	2021	AB128	Appropriates funding for wildlife crossing projects, including the Liberty Canyon crossing for mountain lions
California	2015	AB 498	Amends the California Fish and Game Code to encourage, wherever feasible, voluntary steps to protect the functioning of wildlife corridors
California	2014	AB1471	Provides funds to the Sacramento- San Joaquin Delta Conservancy, in part to protect and restore aquatic, wetland, and migratory bird ecosystems including corridors.
California	2008	AB2785	Orders Dept. of Fish & Wildlife to investigate, study, and identify key wildlife corridors and linkages within the state, and to make those areas public

State	Year	Policy	Description
Florida	2024	SB1638	Dedicates annual funding to land purchases, conservation easements, and trail maintenance within Florida Wildlife Corridor
Florida	2023	HB1379	Creates annual appropriation to acquire lands that complete certain linkages and are under high population stress within Florida Wildlife Corridor
Florida	2023	SB2500 sec.146	Provides funding to buy Ocala to Osceola (“O2O”) Wildlife Corridor
Florida	2021	SB976	Tasks state agencies with maintaining wildlife connectivity and designates Florida Wildlife Corridor as an existing physical, geographically defined area
Florida	2021	SB2500	Appropriates $300 million to acquire lands to conserve Florida Wildlife Corridor
Florida	2019	SB7068	Creates a "Multi-use Corridors of Regional Economic Significance Program" that includes protection of wildlife corridors as an intended benefit
Florida	2008	SB542	Amends Florida Forever Act statues to include goals of connecting linkage corridors
Florida	2001	SB1468	Amends Florida Forever Act to establish that land acquisitions should include complete landscape linkages and corridors
Florida	1999	S908	Creates Florida Forever Program, with increased protection of lands that protect threatened or endangered species and plans to create a statewide system of connected landscape linkages

Forest cover and connectivity impact seed dispersal networks

Monteiro, E.C., Pizo, M.A., Vancine, M.H. and Ribeiro, M.C. 2021. Forest cover and connectivity have pervasive effects on the maintenance of evolutionary distinct interactions in seed dispersal networks. Oikos. DOI: 10.1111/oik.08240.

Related Posts

Habitat fragmentation reduces amphibian defense against disease

Fragmentation limits the natural regeneration of tropical forests

Big cats and big connectivity

Bridging the gap between large-scale connectivity and local management actions

Questioning the effectiveness of corridors for seed dispersal

About the Author: Hazel Anderson